diff --git a/core/linux-kirkwood/0001-block-bfq-attempt-to-fix-use-after-free-which-3.3.0-to-3.8.0.patch b/core/linux-kirkwood/0001-block-bfq-attempt-to-fix-use-after-free-which-3.3.0-to-3.8.0.patch new file mode 100644 index 000000000..fcf8883ca --- /dev/null +++ b/core/linux-kirkwood/0001-block-bfq-attempt-to-fix-use-after-free-which-3.3.0-to-3.8.0.patch @@ -0,0 +1,62 @@ +From 599be431332e31a25ebe203155fa18d34781c3d3 Mon Sep 17 00:00:00 2001 +From: Arianna Avanzini +Date: Tue, 5 Mar 2013 10:41:49 +0100 +Subject: [PATCH] block, bfq: attempt to fix use-after-free which affects SLUB + behavior (3.3.0 to 3.8.0) + +It may happen that a call to bfq_del_bfqq_busy() puts the last +reference taken on a queue and frees it. Subsequent accesses to that +same queue would result in a use-after-free. Make sure that a queue +that has just been deleted from busy is no more touched. +--- + block/bfq-iosched.c | 20 ++++++++++---------- + 1 file changed, 10 insertions(+), 10 deletions(-) + +diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c +index 9378b7d..e9a6514 100644 +--- a/block/bfq-iosched.c ++++ b/block/bfq-iosched.c +@@ -1244,14 +1244,23 @@ static void __bfq_bfqq_expire(struct bfq_data *bfqd, struct bfq_queue *bfqq) + + __bfq_bfqd_reset_active(bfqd); + ++ /* ++ * If this bfqq is shared between multiple processes, check ++ * to make sure that those processes are still issuing I/Os ++ * within the mean seek distance. If not, it may be time to ++ * break the queues apart again. ++ */ ++ if (bfq_bfqq_coop(bfqq) && BFQQ_SEEKY(bfqq)) ++ bfq_mark_bfqq_split_coop(bfqq); ++ + if (RB_EMPTY_ROOT(&bfqq->sort_list)) { +- bfq_del_bfqq_busy(bfqd, bfqq, 1); + /* + * overloading budget_timeout field to store when + * the queue remains with no backlog, used by + * the weight-raising mechanism + */ + bfqq->budget_timeout = jiffies ; ++ bfq_del_bfqq_busy(bfqd, bfqq, 1); + } else { + bfq_activate_bfqq(bfqd, bfqq); + /* +@@ -1259,15 +1268,6 @@ static void __bfq_bfqq_expire(struct bfq_data *bfqd, struct bfq_queue *bfqq) + */ + bfq_rq_pos_tree_add(bfqd, bfqq); + } +- +- /* +- * If this bfqq is shared between multiple processes, check +- * to make sure that those processes are still issuing I/Os +- * within the mean seek distance. If not, it may be time to +- * break the queues apart again. +- */ +- if (bfq_bfqq_coop(bfqq) && BFQQ_SEEKY(bfqq)) +- bfq_mark_bfqq_split_coop(bfqq); + } + + /** +-- +1.8.1.4 + diff --git a/core/linux-kirkwood/0001-block-cgroups-kconfig-build-bits-for-BFQ-v6-3.8.patch b/core/linux-kirkwood/0001-block-cgroups-kconfig-build-bits-for-BFQ-v6-3.8.patch new file mode 100644 index 000000000..80def3584 --- /dev/null +++ b/core/linux-kirkwood/0001-block-cgroups-kconfig-build-bits-for-BFQ-v6-3.8.patch @@ -0,0 +1,97 @@ +From 59fd22f37d9acfa07186a02bb1cd2d64785d82b1 Mon Sep 17 00:00:00 2001 +From: Arianna Avanzini +Date: Sat, 4 Feb 2012 10:55:51 +0100 +Subject: [PATCH 1/2] block: cgroups, kconfig, build bits for BFQ-v6-3.8 + +Update Kconfig.iosched and do the related Makefile changes to include +kernel configuration options for BFQ. Also add the bfqio controller +to the cgroups subsystem. + +Signed-off-by: Paolo Valente +Signed-off-by: Arianna Avanzini +--- + block/Kconfig.iosched | 26 ++++++++++++++++++++++++++ + block/Makefile | 1 + + include/linux/cgroup_subsys.h | 6 ++++++ + 3 files changed, 33 insertions(+) + +diff --git a/block/Kconfig.iosched b/block/Kconfig.iosched +index 421bef9..56474b2 100644 +--- a/block/Kconfig.iosched ++++ b/block/Kconfig.iosched +@@ -39,6 +39,28 @@ config CFQ_GROUP_IOSCHED + ---help--- + Enable group IO scheduling in CFQ. + ++config IOSCHED_BFQ ++ tristate "BFQ I/O scheduler" ++ depends on EXPERIMENTAL ++ default n ++ ---help--- ++ The BFQ I/O scheduler tries to distribute bandwidth among ++ all processes according to their weights. ++ It aims at distributing the bandwidth as desired, independently of ++ the disk parameters and with any workload. It also tries to ++ guarantee low latency to interactive and soft real-time ++ applications. If compiled built-in (saying Y here), BFQ can ++ be configured to support hierarchical scheduling. ++ ++config CGROUP_BFQIO ++ bool "BFQ hierarchical scheduling support" ++ depends on CGROUPS && IOSCHED_BFQ=y ++ default n ++ ---help--- ++ Enable hierarchical scheduling in BFQ, using the cgroups ++ filesystem interface. The name of the subsystem will be ++ bfqio. ++ + choice + prompt "Default I/O scheduler" + default DEFAULT_CFQ +@@ -52,6 +74,9 @@ choice + config DEFAULT_CFQ + bool "CFQ" if IOSCHED_CFQ=y + ++ config DEFAULT_BFQ ++ bool "BFQ" if IOSCHED_BFQ=y ++ + config DEFAULT_NOOP + bool "No-op" + +@@ -61,6 +86,7 @@ config DEFAULT_IOSCHED + string + default "deadline" if DEFAULT_DEADLINE + default "cfq" if DEFAULT_CFQ ++ default "bfq" if DEFAULT_BFQ + default "noop" if DEFAULT_NOOP + + endmenu +diff --git a/block/Makefile b/block/Makefile +index 39b76ba..c0d20fa 100644 +--- a/block/Makefile ++++ b/block/Makefile +@@ -15,6 +15,7 @@ obj-$(CONFIG_BLK_DEV_THROTTLING) += blk-throttle.o + obj-$(CONFIG_IOSCHED_NOOP) += noop-iosched.o + obj-$(CONFIG_IOSCHED_DEADLINE) += deadline-iosched.o + obj-$(CONFIG_IOSCHED_CFQ) += cfq-iosched.o ++obj-$(CONFIG_IOSCHED_BFQ) += bfq-iosched.o + + obj-$(CONFIG_BLOCK_COMPAT) += compat_ioctl.o + obj-$(CONFIG_BLK_DEV_INTEGRITY) += blk-integrity.o +diff --git a/include/linux/cgroup_subsys.h b/include/linux/cgroup_subsys.h +index f204a7a..b999bfa 100644 +--- a/include/linux/cgroup_subsys.h ++++ b/include/linux/cgroup_subsys.h +@@ -78,3 +78,9 @@ SUBSYS(hugetlb) + #endif + + /* */ ++ ++#ifdef CONFIG_CGROUP_BFQIO ++SUBSYS(bfqio) ++#endif ++ ++/* */ +-- +1.8.1.2 + diff --git a/core/linux-kirkwood/0002-block-introduce-the-BFQ-v6-I-O-sched-for-3.8.patch b/core/linux-kirkwood/0002-block-introduce-the-BFQ-v6-I-O-sched-for-3.8.patch new file mode 100644 index 000000000..7856f7323 --- /dev/null +++ b/core/linux-kirkwood/0002-block-introduce-the-BFQ-v6-I-O-sched-for-3.8.patch @@ -0,0 +1,5855 @@ +From d2ba3dc4196b2b1579f6ccbb64880e662684b8ba Mon Sep 17 00:00:00 2001 +From: Arianna Avanzini +Date: Sun, 5 Feb 2012 01:04:27 +0100 +Subject: [PATCH 2/2] block: introduce the BFQ-v6 I/O sched for 3.8 + +Add the BFQ-v6 I/O scheduler to 3.8. +The general structure is borrowed from CFQ, as much code. A (bfq_)queue is +associated to each task doing I/O on a device, and each time a scheduling +decision has to be made a queue is selected and served until it expires. + + - Slices are given in the service domain: tasks are assigned budgets, + measured in number of sectors. Once got the disk, a task must + however consume its assigned budget within a configurable maximum time + (by default, the maximum possible value of the budgets is automatically + computed to comply with this timeout). This allows the desired latency + vs "throughput boosting" tradeoff to be set. + + - Budgets are scheduled according to a variant of WF2Q+, implemented + using an augmented rb-tree to take eligibility into account while + preserving an O(log N) overall complexity. + + - A low-latency tunable is provided; if enabled, both interactive and soft + real-time applications are guaranteed very low latency. + + - Latency guarantees are preserved also in presence of NCQ. + + - Also with flash-based devices, a high throughput is achieved while + still preserving latency guarantees. + + - A useful feature borrowed from CFQ: static fallback queue for OOM. + + - Differently from CFQ, BFQ uses a unified mechanism (Early Queue Merge, + EQM) to get a sequential read pattern, and hence a high throughput, + with any set of processes performing interleaved I/O. EQM also + preserves low latency. The code for detecting whether two queues have + to be merged is a slightly modified version of the CFQ code for + detecting whether two queues belong to cooperating processes and whether + the service of a queue should be preempted to boost the throughput. + + - BFQ supports full hierarchical scheduling, exporting a cgroups + interface. Each node has a full scheduler, so each group can + be assigned its own ioprio (mapped to a weight, see next point) + and an ioprio_class. + + - If the cgroups interface is used, weights can be explictly assigned, + otherwise ioprio values are mapped to weights using the relation + weight = IOPRIO_BE_NR - ioprio. + + - ioprio classes are served in strict priority order, i.e., lower + priority queues are not served as long as there are higher priority + queues. Among queues in the same class the bandwidth is distributed + in proportion to the weight of each queue. A very thin extra bandwidth + is however guaranteed to the Idle class, to prevent it from starving. + +Signed-off-by: Paolo Valente +Signed-off-by: Arianna Avanzini +--- + block/bfq-cgroup.c | 838 ++++++++++++++ + block/bfq-ioc.c | 36 + + block/bfq-iosched.c | 3218 +++++++++++++++++++++++++++++++++++++++++++++++++++ + block/bfq-sched.c | 1044 +++++++++++++++++ + block/bfq.h | 617 ++++++++++ + 5 files changed, 5753 insertions(+) + create mode 100644 block/bfq-cgroup.c + create mode 100644 block/bfq-ioc.c + create mode 100644 block/bfq-iosched.c + create mode 100644 block/bfq-sched.c + create mode 100644 block/bfq.h + +diff --git a/block/bfq-cgroup.c b/block/bfq-cgroup.c +new file mode 100644 +index 0000000..1ae54d1 +--- /dev/null ++++ b/block/bfq-cgroup.c +@@ -0,0 +1,838 @@ ++/* ++ * BFQ: CGROUPS support. ++ * ++ * Based on ideas and code from CFQ: ++ * Copyright (C) 2003 Jens Axboe ++ * ++ * Copyright (C) 2008 Fabio Checconi ++ * Paolo Valente ++ * ++ * Copyright (C) 2010 Paolo Valente ++ * ++ * Licensed under the GPL-2 as detailed in the accompanying COPYING.BFQ file. ++ */ ++ ++#ifdef CONFIG_CGROUP_BFQIO ++static struct bfqio_cgroup bfqio_root_cgroup = { ++ .weight = BFQ_DEFAULT_GRP_WEIGHT, ++ .ioprio = BFQ_DEFAULT_GRP_IOPRIO, ++ .ioprio_class = BFQ_DEFAULT_GRP_CLASS, ++}; ++ ++static inline void bfq_init_entity(struct bfq_entity *entity, ++ struct bfq_group *bfqg) ++{ ++ entity->weight = entity->new_weight; ++ entity->orig_weight = entity->new_weight; ++ entity->ioprio = entity->new_ioprio; ++ entity->ioprio_class = entity->new_ioprio_class; ++ entity->parent = bfqg->my_entity; ++ entity->sched_data = &bfqg->sched_data; ++} ++ ++static struct bfqio_cgroup *cgroup_to_bfqio(struct cgroup *cgroup) ++{ ++ return container_of(cgroup_subsys_state(cgroup, bfqio_subsys_id), ++ struct bfqio_cgroup, css); ++} ++ ++/* ++ * Search the bfq_group for bfqd into the hash table (by now only a list) ++ * of bgrp. Must be called under rcu_read_lock(). ++ */ ++static struct bfq_group *bfqio_lookup_group(struct bfqio_cgroup *bgrp, ++ struct bfq_data *bfqd) ++{ ++ struct bfq_group *bfqg; ++ struct hlist_node *n; ++ void *key; ++ ++ hlist_for_each_entry_rcu(bfqg, n, &bgrp->group_data, group_node) { ++ key = rcu_dereference(bfqg->bfqd); ++ if (key == bfqd) ++ return bfqg; ++ } ++ ++ return NULL; ++} ++ ++static inline void bfq_group_init_entity(struct bfqio_cgroup *bgrp, ++ struct bfq_group *bfqg) ++{ ++ struct bfq_entity *entity = &bfqg->entity; ++ ++ entity->weight = entity->new_weight = bgrp->weight; ++ entity->orig_weight = entity->new_weight; ++ entity->ioprio = entity->new_ioprio = bgrp->ioprio; ++ entity->ioprio_class = entity->new_ioprio_class = bgrp->ioprio_class; ++ entity->ioprio_changed = 1; ++ entity->my_sched_data = &bfqg->sched_data; ++} ++ ++static inline void bfq_group_set_parent(struct bfq_group *bfqg, ++ struct bfq_group *parent) ++{ ++ struct bfq_entity *entity; ++ ++ BUG_ON(parent == NULL); ++ BUG_ON(bfqg == NULL); ++ ++ entity = &bfqg->entity; ++ entity->parent = parent->my_entity; ++ entity->sched_data = &parent->sched_data; ++} ++ ++/** ++ * bfq_group_chain_alloc - allocate a chain of groups. ++ * @bfqd: queue descriptor. ++ * @cgroup: the leaf cgroup this chain starts from. ++ * ++ * Allocate a chain of groups starting from the one belonging to ++ * @cgroup up to the root cgroup. Stop if a cgroup on the chain ++ * to the root has already an allocated group on @bfqd. ++ */ ++static struct bfq_group *bfq_group_chain_alloc(struct bfq_data *bfqd, ++ struct cgroup *cgroup) ++{ ++ struct bfqio_cgroup *bgrp; ++ struct bfq_group *bfqg, *prev = NULL, *leaf = NULL; ++ ++ for (; cgroup != NULL; cgroup = cgroup->parent) { ++ bgrp = cgroup_to_bfqio(cgroup); ++ ++ bfqg = bfqio_lookup_group(bgrp, bfqd); ++ if (bfqg != NULL) { ++ /* ++ * All the cgroups in the path from there to the ++ * root must have a bfq_group for bfqd, so we don't ++ * need any more allocations. ++ */ ++ break; ++ } ++ ++ bfqg = kzalloc(sizeof(*bfqg), GFP_ATOMIC); ++ if (bfqg == NULL) ++ goto cleanup; ++ ++ bfq_group_init_entity(bgrp, bfqg); ++ bfqg->my_entity = &bfqg->entity; ++ ++ if (leaf == NULL) { ++ leaf = bfqg; ++ prev = leaf; ++ } else { ++ bfq_group_set_parent(prev, bfqg); ++ /* ++ * Build a list of allocated nodes using the bfqd ++ * filed, that is still unused and will be initialized ++ * only after the node will be connected. ++ */ ++ prev->bfqd = bfqg; ++ prev = bfqg; ++ } ++ } ++ ++ return leaf; ++ ++cleanup: ++ while (leaf != NULL) { ++ prev = leaf; ++ leaf = leaf->bfqd; ++ kfree(prev); ++ } ++ ++ return NULL; ++} ++ ++/** ++ * bfq_group_chain_link - link an allocatd group chain to a cgroup hierarchy. ++ * @bfqd: the queue descriptor. ++ * @cgroup: the leaf cgroup to start from. ++ * @leaf: the leaf group (to be associated to @cgroup). ++ * ++ * Try to link a chain of groups to a cgroup hierarchy, connecting the ++ * nodes bottom-up, so we can be sure that when we find a cgroup in the ++ * hierarchy that already as a group associated to @bfqd all the nodes ++ * in the path to the root cgroup have one too. ++ * ++ * On locking: the queue lock protects the hierarchy (there is a hierarchy ++ * per device) while the bfqio_cgroup lock protects the list of groups ++ * belonging to the same cgroup. ++ */ ++static void bfq_group_chain_link(struct bfq_data *bfqd, struct cgroup *cgroup, ++ struct bfq_group *leaf) ++{ ++ struct bfqio_cgroup *bgrp; ++ struct bfq_group *bfqg, *next, *prev = NULL; ++ unsigned long flags; ++ ++ assert_spin_locked(bfqd->queue->queue_lock); ++ ++ for (; cgroup != NULL && leaf != NULL; cgroup = cgroup->parent) { ++ bgrp = cgroup_to_bfqio(cgroup); ++ next = leaf->bfqd; ++ ++ bfqg = bfqio_lookup_group(bgrp, bfqd); ++ BUG_ON(bfqg != NULL); ++ ++ spin_lock_irqsave(&bgrp->lock, flags); ++ ++ rcu_assign_pointer(leaf->bfqd, bfqd); ++ hlist_add_head_rcu(&leaf->group_node, &bgrp->group_data); ++ hlist_add_head(&leaf->bfqd_node, &bfqd->group_list); ++ ++ spin_unlock_irqrestore(&bgrp->lock, flags); ++ ++ prev = leaf; ++ leaf = next; ++ } ++ ++ BUG_ON(cgroup == NULL && leaf != NULL); ++ if (cgroup != NULL && prev != NULL) { ++ bgrp = cgroup_to_bfqio(cgroup); ++ bfqg = bfqio_lookup_group(bgrp, bfqd); ++ bfq_group_set_parent(prev, bfqg); ++ } ++} ++ ++/** ++ * bfq_find_alloc_group - return the group associated to @bfqd in @cgroup. ++ * @bfqd: queue descriptor. ++ * @cgroup: cgroup being searched for. ++ * ++ * Return a group associated to @bfqd in @cgroup, allocating one if ++ * necessary. When a group is returned all the cgroups in the path ++ * to the root have a group associated to @bfqd. ++ * ++ * If the allocation fails, return the root group: this breaks guarantees ++ * but is a safe fallbak. If this loss becames a problem it can be ++ * mitigated using the equivalent weight (given by the product of the ++ * weights of the groups in the path from @group to the root) in the ++ * root scheduler. ++ * ++ * We allocate all the missing nodes in the path from the leaf cgroup ++ * to the root and we connect the nodes only after all the allocations ++ * have been successful. ++ */ ++static struct bfq_group *bfq_find_alloc_group(struct bfq_data *bfqd, ++ struct cgroup *cgroup) ++{ ++ struct bfqio_cgroup *bgrp = cgroup_to_bfqio(cgroup); ++ struct bfq_group *bfqg; ++ ++ bfqg = bfqio_lookup_group(bgrp, bfqd); ++ if (bfqg != NULL) ++ return bfqg; ++ ++ bfqg = bfq_group_chain_alloc(bfqd, cgroup); ++ if (bfqg != NULL) ++ bfq_group_chain_link(bfqd, cgroup, bfqg); ++ else ++ bfqg = bfqd->root_group; ++ ++ return bfqg; ++} ++ ++/** ++ * bfq_bfqq_move - migrate @bfqq to @bfqg. ++ * @bfqd: queue descriptor. ++ * @bfqq: the queue to move. ++ * @entity: @bfqq's entity. ++ * @bfqg: the group to move to. ++ * ++ * Move @bfqq to @bfqg, deactivating it from its old group and reactivating ++ * it on the new one. Avoid putting the entity on the old group idle tree. ++ * ++ * Must be called under the queue lock; the cgroup owning @bfqg must ++ * not disappear (by now this just means that we are called under ++ * rcu_read_lock()). ++ */ ++static void bfq_bfqq_move(struct bfq_data *bfqd, struct bfq_queue *bfqq, ++ struct bfq_entity *entity, struct bfq_group *bfqg) ++{ ++ int busy, resume; ++ ++ busy = bfq_bfqq_busy(bfqq); ++ resume = !RB_EMPTY_ROOT(&bfqq->sort_list); ++ ++ BUG_ON(resume && !entity->on_st); ++ BUG_ON(busy && !resume && entity->on_st && bfqq != bfqd->active_queue); ++ ++ if (busy) { ++ BUG_ON(atomic_read(&bfqq->ref) < 2); ++ ++ if (!resume) ++ bfq_del_bfqq_busy(bfqd, bfqq, 0); ++ else ++ bfq_deactivate_bfqq(bfqd, bfqq, 0); ++ } else if (entity->on_st) ++ bfq_put_idle_entity(bfq_entity_service_tree(entity), entity); ++ ++ /* ++ * Here we use a reference to bfqg. We don't need a refcounter ++ * as the cgroup reference will not be dropped, so that its ++ * destroy() callback will not be invoked. ++ */ ++ entity->parent = bfqg->my_entity; ++ entity->sched_data = &bfqg->sched_data; ++ ++ if (busy && resume) ++ bfq_activate_bfqq(bfqd, bfqq); ++ ++ if (bfqd->active_queue == NULL && !bfqd->rq_in_driver) ++ bfq_schedule_dispatch(bfqd); ++} ++ ++/** ++ * __bfq_bic_change_cgroup - move @bic to @cgroup. ++ * @bfqd: the queue descriptor. ++ * @bic: the bic to move. ++ * @cgroup: the cgroup to move to. ++ * ++ * Move bic to cgroup, assuming that bfqd->queue is locked; the caller ++ * has to make sure that the reference to cgroup is valid across the call. ++ * ++ * NOTE: an alternative approach might have been to store the current ++ * cgroup in bfqq and getting a reference to it, reducing the lookup ++ * time here, at the price of slightly more complex code. ++ */ ++static struct bfq_group *__bfq_bic_change_cgroup(struct bfq_data *bfqd, ++ struct bfq_io_cq *bic, ++ struct cgroup *cgroup) ++{ ++ struct bfq_queue *async_bfqq = bic_to_bfqq(bic, 0); ++ struct bfq_queue *sync_bfqq = bic_to_bfqq(bic, 1); ++ struct bfq_entity *entity; ++ struct bfq_group *bfqg; ++ struct bfqio_cgroup *bgrp; ++ ++ bgrp = cgroup_to_bfqio(cgroup); ++ ++ bfqg = bfq_find_alloc_group(bfqd, cgroup); ++ if (async_bfqq != NULL) { ++ entity = &async_bfqq->entity; ++ ++ if (entity->sched_data != &bfqg->sched_data) { ++ bic_set_bfqq(bic, NULL, 0); ++ bfq_log_bfqq(bfqd, async_bfqq, ++ "bic_change_group: %p %d", ++ async_bfqq, atomic_read(&async_bfqq->ref)); ++ bfq_put_queue(async_bfqq); ++ } ++ } ++ ++ if (sync_bfqq != NULL) { ++ entity = &sync_bfqq->entity; ++ if (entity->sched_data != &bfqg->sched_data) ++ bfq_bfqq_move(bfqd, sync_bfqq, entity, bfqg); ++ } ++ ++ return bfqg; ++} ++ ++/** ++ * bfq_bic_change_cgroup - move @bic to @cgroup. ++ * @bic: the bic being migrated. ++ * @cgroup: the destination cgroup. ++ * ++ * When the task owning @bic is moved to @cgroup, @bic is immediately ++ * moved into its new parent group. ++ */ ++static void bfq_bic_change_cgroup(struct bfq_io_cq *bic, ++ struct cgroup *cgroup) ++{ ++ struct bfq_data *bfqd; ++ unsigned long uninitialized_var(flags); ++ ++ bfqd = bfq_get_bfqd_locked(&(bic->icq.q->elevator->elevator_data), &flags); ++ if (bfqd != NULL) { ++ __bfq_bic_change_cgroup(bfqd, bic, cgroup); ++ bfq_put_bfqd_unlock(bfqd, &flags); ++ } ++} ++ ++/** ++ * bfq_bic_update_cgroup - update the cgroup of @bic. ++ * @bic: the @bic to update. ++ * ++ * Make sure that @bic is enqueued in the cgroup of the current task. ++ * We need this in addition to moving bics during the cgroup attach ++ * phase because the task owning @bic could be at its first disk ++ * access or we may end up in the root cgroup as the result of a ++ * memory allocation failure and here we try to move to the right ++ * group. ++ * ++ * Must be called under the queue lock. It is safe to use the returned ++ * value even after the rcu_read_unlock() as the migration/destruction ++ * paths act under the queue lock too. IOW it is impossible to race with ++ * group migration/destruction and end up with an invalid group as: ++ * a) here cgroup has not yet been destroyed, nor its destroy callback ++ * has started execution, as current holds a reference to it, ++ * b) if it is destroyed after rcu_read_unlock() [after current is ++ * migrated to a different cgroup] its attach() callback will have ++ * taken care of remove all the references to the old cgroup data. ++ */ ++static struct bfq_group *bfq_bic_update_cgroup(struct bfq_io_cq *bic) ++{ ++ struct bfq_data *bfqd = bic_to_bfqd(bic); ++ struct bfq_group *bfqg; ++ struct cgroup *cgroup; ++ ++ BUG_ON(bfqd == NULL); ++ ++ rcu_read_lock(); ++ cgroup = task_cgroup(current, bfqio_subsys_id); ++ bfqg = __bfq_bic_change_cgroup(bfqd, bic, cgroup); ++ rcu_read_unlock(); ++ ++ return bfqg; ++} ++ ++/** ++ * bfq_flush_idle_tree - deactivate any entity on the idle tree of @st. ++ * @st: the service tree being flushed. ++ */ ++static inline void bfq_flush_idle_tree(struct bfq_service_tree *st) ++{ ++ struct bfq_entity *entity = st->first_idle; ++ ++ for (; entity != NULL; entity = st->first_idle) ++ __bfq_deactivate_entity(entity, 0); ++} ++ ++/** ++ * bfq_reparent_leaf_entity - move leaf entity to the root_group. ++ * @bfqd: the device data structure with the root group. ++ * @entity: the entity to move. ++ */ ++static inline void bfq_reparent_leaf_entity(struct bfq_data *bfqd, ++ struct bfq_entity *entity) ++{ ++ struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity); ++ ++ BUG_ON(bfqq == NULL); ++ bfq_bfqq_move(bfqd, bfqq, entity, bfqd->root_group); ++ return; ++} ++ ++/** ++ * bfq_reparent_active_entities - move to the root group all active entities. ++ * @bfqd: the device data structure with the root group. ++ * @bfqg: the group to move from. ++ * @st: the service tree with the entities. ++ * ++ * Needs queue_lock to be taken and reference to be valid over the call. ++ */ ++static inline void bfq_reparent_active_entities(struct bfq_data *bfqd, ++ struct bfq_group *bfqg, ++ struct bfq_service_tree *st) ++{ ++ struct rb_root *active = &st->active; ++ struct bfq_entity *entity = NULL; ++ ++ if (!RB_EMPTY_ROOT(&st->active)) ++ entity = bfq_entity_of(rb_first(active)); ++ ++ for (; entity != NULL ; entity = bfq_entity_of(rb_first(active))) ++ bfq_reparent_leaf_entity(bfqd, entity); ++ ++ if (bfqg->sched_data.active_entity != NULL) ++ bfq_reparent_leaf_entity(bfqd, bfqg->sched_data.active_entity); ++ ++ return; ++} ++ ++/** ++ * bfq_destroy_group - destroy @bfqg. ++ * @bgrp: the bfqio_cgroup containing @bfqg. ++ * @bfqg: the group being destroyed. ++ * ++ * Destroy @bfqg, making sure that it is not referenced from its parent. ++ */ ++static void bfq_destroy_group(struct bfqio_cgroup *bgrp, struct bfq_group *bfqg) ++{ ++ struct bfq_data *bfqd; ++ struct bfq_service_tree *st; ++ struct bfq_entity *entity = bfqg->my_entity; ++ unsigned long uninitialized_var(flags); ++ int i; ++ ++ hlist_del(&bfqg->group_node); ++ ++ /* ++ * Empty all service_trees belonging to this group before deactivating ++ * the group itself. ++ */ ++ for (i = 0; i < BFQ_IOPRIO_CLASSES; i++) { ++ st = bfqg->sched_data.service_tree + i; ++ ++ /* ++ * The idle tree may still contain bfq_queues belonging ++ * to exited task because they never migrated to a different ++ * cgroup from the one being destroyed now. Noone else ++ * can access them so it's safe to act without any lock. ++ */ ++ bfq_flush_idle_tree(st); ++ ++ /* ++ * It may happen that some queues are still active ++ * (busy) upon group destruction (if the corresponding ++ * processes have been forced to terminate). We move ++ * all the leaf entities corresponding to these queues ++ * to the root_group. ++ * Also, it may happen that the group has an entity ++ * under service, which is disconnected from the active ++ * tree: it must be moved, too. ++ * There is no need to put the sync queues, as the ++ * scheduler has taken no reference. ++ */ ++ bfqd = bfq_get_bfqd_locked(&bfqg->bfqd, &flags); ++ if (bfqd != NULL) { ++ bfq_reparent_active_entities(bfqd, bfqg, st); ++ bfq_put_bfqd_unlock(bfqd, &flags); ++ } ++ BUG_ON(!RB_EMPTY_ROOT(&st->active)); ++ BUG_ON(!RB_EMPTY_ROOT(&st->idle)); ++ } ++ BUG_ON(bfqg->sched_data.next_active != NULL); ++ BUG_ON(bfqg->sched_data.active_entity != NULL); ++ ++ /* ++ * We may race with device destruction, take extra care when ++ * dereferencing bfqg->bfqd. ++ */ ++ bfqd = bfq_get_bfqd_locked(&bfqg->bfqd, &flags); ++ if (bfqd != NULL) { ++ hlist_del(&bfqg->bfqd_node); ++ __bfq_deactivate_entity(entity, 0); ++ bfq_put_async_queues(bfqd, bfqg); ++ bfq_put_bfqd_unlock(bfqd, &flags); ++ } ++ BUG_ON(entity->tree != NULL); ++ ++ /* ++ * No need to defer the kfree() to the end of the RCU grace ++ * period: we are called from the destroy() callback of our ++ * cgroup, so we can be sure that noone is a) still using ++ * this cgroup or b) doing lookups in it. ++ */ ++ kfree(bfqg); ++} ++ ++/** ++ * bfq_disconnect_groups - diconnect @bfqd from all its groups. ++ * @bfqd: the device descriptor being exited. ++ * ++ * When the device exits we just make sure that no lookup can return ++ * the now unused group structures. They will be deallocated on cgroup ++ * destruction. ++ */ ++static void bfq_disconnect_groups(struct bfq_data *bfqd) ++{ ++ struct hlist_node *pos, *n; ++ struct bfq_group *bfqg; ++ ++ bfq_log(bfqd, "disconnect_groups beginning") ; ++ hlist_for_each_entry_safe(bfqg, pos, n, &bfqd->group_list, bfqd_node) { ++ hlist_del(&bfqg->bfqd_node); ++ ++ __bfq_deactivate_entity(bfqg->my_entity, 0); ++ ++ /* ++ * Don't remove from the group hash, just set an ++ * invalid key. No lookups can race with the ++ * assignment as bfqd is being destroyed; this ++ * implies also that new elements cannot be added ++ * to the list. ++ */ ++ rcu_assign_pointer(bfqg->bfqd, NULL); ++ ++ bfq_log(bfqd, "disconnect_groups: put async for group %p", ++ bfqg) ; ++ bfq_put_async_queues(bfqd, bfqg); ++ } ++} ++ ++static inline void bfq_free_root_group(struct bfq_data *bfqd) ++{ ++ struct bfqio_cgroup *bgrp = &bfqio_root_cgroup; ++ struct bfq_group *bfqg = bfqd->root_group; ++ ++ bfq_put_async_queues(bfqd, bfqg); ++ ++ spin_lock_irq(&bgrp->lock); ++ hlist_del_rcu(&bfqg->group_node); ++ spin_unlock_irq(&bgrp->lock); ++ ++ /* ++ * No need to synchronize_rcu() here: since the device is gone ++ * there cannot be any read-side access to its root_group. ++ */ ++ kfree(bfqg); ++} ++ ++static struct bfq_group *bfq_alloc_root_group(struct bfq_data *bfqd, int node) ++{ ++ struct bfq_group *bfqg; ++ struct bfqio_cgroup *bgrp; ++ int i; ++ ++ bfqg = kmalloc_node(sizeof(*bfqg), GFP_KERNEL | __GFP_ZERO, node); ++ if (bfqg == NULL) ++ return NULL; ++ ++ bfqg->entity.parent = NULL; ++ for (i = 0; i < BFQ_IOPRIO_CLASSES; i++) ++ bfqg->sched_data.service_tree[i] = BFQ_SERVICE_TREE_INIT; ++ ++ bgrp = &bfqio_root_cgroup; ++ spin_lock_irq(&bgrp->lock); ++ rcu_assign_pointer(bfqg->bfqd, bfqd); ++ hlist_add_head_rcu(&bfqg->group_node, &bgrp->group_data); ++ spin_unlock_irq(&bgrp->lock); ++ ++ return bfqg; ++} ++ ++#define SHOW_FUNCTION(__VAR) \ ++static u64 bfqio_cgroup_##__VAR##_read(struct cgroup *cgroup, \ ++ struct cftype *cftype) \ ++{ \ ++ struct bfqio_cgroup *bgrp; \ ++ u64 ret; \ ++ \ ++ if (!cgroup_lock_live_group(cgroup)) \ ++ return -ENODEV; \ ++ \ ++ bgrp = cgroup_to_bfqio(cgroup); \ ++ spin_lock_irq(&bgrp->lock); \ ++ ret = bgrp->__VAR; \ ++ spin_unlock_irq(&bgrp->lock); \ ++ \ ++ cgroup_unlock(); \ ++ \ ++ return ret; \ ++} ++ ++SHOW_FUNCTION(weight); ++SHOW_FUNCTION(ioprio); ++SHOW_FUNCTION(ioprio_class); ++#undef SHOW_FUNCTION ++ ++#define STORE_FUNCTION(__VAR, __MIN, __MAX) \ ++static int bfqio_cgroup_##__VAR##_write(struct cgroup *cgroup, \ ++ struct cftype *cftype, \ ++ u64 val) \ ++{ \ ++ struct bfqio_cgroup *bgrp; \ ++ struct bfq_group *bfqg; \ ++ struct hlist_node *n; \ ++ \ ++ if (val < (__MIN) || val > (__MAX)) \ ++ return -EINVAL; \ ++ \ ++ if (!cgroup_lock_live_group(cgroup)) \ ++ return -ENODEV; \ ++ \ ++ bgrp = cgroup_to_bfqio(cgroup); \ ++ \ ++ spin_lock_irq(&bgrp->lock); \ ++ bgrp->__VAR = (unsigned short)val; \ ++ hlist_for_each_entry(bfqg, n, &bgrp->group_data, group_node) { \ ++ bfqg->entity.new_##__VAR = (unsigned short)val; \ ++ smp_wmb(); \ ++ bfqg->entity.ioprio_changed = 1; \ ++ } \ ++ spin_unlock_irq(&bgrp->lock); \ ++ \ ++ cgroup_unlock(); \ ++ \ ++ return 0; \ ++} ++ ++STORE_FUNCTION(weight, BFQ_MIN_WEIGHT, BFQ_MAX_WEIGHT); ++STORE_FUNCTION(ioprio, 0, IOPRIO_BE_NR - 1); ++STORE_FUNCTION(ioprio_class, IOPRIO_CLASS_RT, IOPRIO_CLASS_IDLE); ++#undef STORE_FUNCTION ++ ++static struct cftype bfqio_files[] = { ++ { ++ .name = "weight", ++ .read_u64 = bfqio_cgroup_weight_read, ++ .write_u64 = bfqio_cgroup_weight_write, ++ }, ++ { ++ .name = "ioprio", ++ .read_u64 = bfqio_cgroup_ioprio_read, ++ .write_u64 = bfqio_cgroup_ioprio_write, ++ }, ++ { ++ .name = "ioprio_class", ++ .read_u64 = bfqio_cgroup_ioprio_class_read, ++ .write_u64 = bfqio_cgroup_ioprio_class_write, ++ }, ++ { }, /* terminate */ ++}; ++ ++static struct cgroup_subsys_state *bfqio_create(struct cgroup *cgroup) ++{ ++ struct bfqio_cgroup *bgrp; ++ ++ if (cgroup->parent != NULL) { ++ bgrp = kzalloc(sizeof(*bgrp), GFP_KERNEL); ++ if (bgrp == NULL) ++ return ERR_PTR(-ENOMEM); ++ } else ++ bgrp = &bfqio_root_cgroup; ++ ++ spin_lock_init(&bgrp->lock); ++ INIT_HLIST_HEAD(&bgrp->group_data); ++ bgrp->ioprio = BFQ_DEFAULT_GRP_IOPRIO; ++ bgrp->ioprio_class = BFQ_DEFAULT_GRP_CLASS; ++ ++ return &bgrp->css; ++} ++ ++/* ++ * We cannot support shared io contexts, as we have no means to support ++ * two tasks with the same ioc in two different groups without major rework ++ * of the main bic/bfqq data structures. By now we allow a task to change ++ * its cgroup only if it's the only owner of its ioc; the drawback of this ++ * behavior is that a group containing a task that forked using CLONE_IO ++ * will not be destroyed until the tasks sharing the ioc die. ++ */ ++static int bfqio_can_attach(struct cgroup *cgroup, struct cgroup_taskset *tset) ++{ ++ struct task_struct *task; ++ struct io_context *ioc; ++ int ret = 0; ++ ++ cgroup_taskset_for_each(task, cgroup, tset) { ++ /* task_lock() is needed to avoid races with exit_io_context() */ ++ task_lock(task); ++ ioc = task->io_context; ++ if (ioc != NULL && atomic_read(&ioc->nr_tasks) > 1) ++ /* ++ * ioc == NULL means that the task is either too young or ++ * exiting: if it has still no ioc the ioc can't be shared, ++ * if the task is exiting the attach will fail anyway, no ++ * matter what we return here. ++ */ ++ ret = -EINVAL; ++ task_unlock(task); ++ if (ret) ++ break; ++ } ++ ++ return ret; ++} ++ ++static void bfqio_attach(struct cgroup *cgroup, struct cgroup_taskset *tset) ++{ ++ struct task_struct *task; ++ struct io_context *ioc; ++ struct io_cq *icq; ++ struct hlist_node *n; ++ ++ /* ++ * IMPORTANT NOTE: The move of more than one process at a time to a ++ * new group has not yet been tested. ++ */ ++ cgroup_taskset_for_each(task, cgroup, tset) { ++ ioc = get_task_io_context(task, GFP_ATOMIC, NUMA_NO_NODE); ++ if (ioc) { ++ /* ++ * Handle cgroup change here. ++ */ ++ rcu_read_lock(); ++ hlist_for_each_entry_rcu(icq, n, &ioc->icq_list, ioc_node) ++ if (!strncmp(icq->q->elevator->type->elevator_name, ++ "bfq", ELV_NAME_MAX)) ++ bfq_bic_change_cgroup(icq_to_bic(icq), ++ cgroup); ++ rcu_read_unlock(); ++ put_io_context(ioc); ++ } ++ } ++} ++ ++static void bfqio_destroy(struct cgroup *cgroup) ++{ ++ struct bfqio_cgroup *bgrp = cgroup_to_bfqio(cgroup); ++ struct hlist_node *n, *tmp; ++ struct bfq_group *bfqg; ++ ++ /* ++ * Since we are destroying the cgroup, there are no more tasks ++ * referencing it, and all the RCU grace periods that may have ++ * referenced it are ended (as the destruction of the parent ++ * cgroup is RCU-safe); bgrp->group_data will not be accessed by ++ * anything else and we don't need any synchronization. ++ */ ++ hlist_for_each_entry_safe(bfqg, n, tmp, &bgrp->group_data, group_node) ++ bfq_destroy_group(bgrp, bfqg); ++ ++ BUG_ON(!hlist_empty(&bgrp->group_data)); ++ ++ kfree(bgrp); ++} ++ ++struct cgroup_subsys bfqio_subsys = { ++ .name = "bfqio", ++ .css_alloc = bfqio_create, ++ .can_attach = bfqio_can_attach, ++ .attach = bfqio_attach, ++ .css_free = bfqio_destroy, ++ .subsys_id = bfqio_subsys_id, ++ .base_cftypes = bfqio_files, ++}; ++#else ++static inline void bfq_init_entity(struct bfq_entity *entity, ++ struct bfq_group *bfqg) ++{ ++ entity->weight = entity->new_weight; ++ entity->orig_weight = entity->new_weight; ++ entity->ioprio = entity->new_ioprio; ++ entity->ioprio_class = entity->new_ioprio_class; ++ entity->sched_data = &bfqg->sched_data; ++} ++ ++static inline struct bfq_group * ++bfq_bic_update_cgroup(struct bfq_io_cq *bic) ++{ ++ struct bfq_data *bfqd = bic_to_bfqd(bic); ++ return bfqd->root_group; ++} ++ ++static inline void bfq_bfqq_move(struct bfq_data *bfqd, ++ struct bfq_queue *bfqq, ++ struct bfq_entity *entity, ++ struct bfq_group *bfqg) ++{ ++} ++ ++static inline void bfq_disconnect_groups(struct bfq_data *bfqd) ++{ ++ bfq_put_async_queues(bfqd, bfqd->root_group); ++} ++ ++static inline void bfq_free_root_group(struct bfq_data *bfqd) ++{ ++ kfree(bfqd->root_group); ++} ++ ++static struct bfq_group *bfq_alloc_root_group(struct bfq_data *bfqd, int node) ++{ ++ struct bfq_group *bfqg; ++ int i; ++ ++ bfqg = kmalloc_node(sizeof(*bfqg), GFP_KERNEL | __GFP_ZERO, node); ++ if (bfqg == NULL) ++ return NULL; ++ ++ for (i = 0; i < BFQ_IOPRIO_CLASSES; i++) ++ bfqg->sched_data.service_tree[i] = BFQ_SERVICE_TREE_INIT; ++ ++ return bfqg; ++} ++#endif +diff --git a/block/bfq-ioc.c b/block/bfq-ioc.c +new file mode 100644 +index 0000000..326e3ec +--- /dev/null ++++ b/block/bfq-ioc.c +@@ -0,0 +1,36 @@ ++/* ++ * BFQ: I/O context handling. ++ * ++ * Based on ideas and code from CFQ: ++ * Copyright (C) 2003 Jens Axboe ++ * ++ * Copyright (C) 2008 Fabio Checconi ++ * Paolo Valente ++ * ++ * Copyright (C) 2010 Paolo Valente ++ */ ++ ++/** ++ * icq_to_bic - convert iocontext queue structure to bfq_io_cq. ++ * @icq: the iocontext queue. ++ */ ++static inline struct bfq_io_cq *icq_to_bic(struct io_cq *icq) ++{ ++ /* bic->icq is the first member, %NULL will convert to %NULL */ ++ return container_of(icq, struct bfq_io_cq, icq); ++} ++ ++/** ++ * bfq_bic_lookup - search into @ioc a bic associated to @bfqd. ++ * @bfqd: the lookup key. ++ * @ioc: the io_context of the process doing I/O. ++ * ++ * Queue lock must be held. ++ */ ++static inline struct bfq_io_cq *bfq_bic_lookup(struct bfq_data *bfqd, ++ struct io_context *ioc) ++{ ++ if(ioc) ++ return icq_to_bic(ioc_lookup_icq(ioc, bfqd->queue)); ++ return NULL; ++} +diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c +new file mode 100644 +index 0000000..c9d57b0 +--- /dev/null ++++ b/block/bfq-iosched.c +@@ -0,0 +1,3218 @@ ++/* ++ * BFQ, or Budget Fair Queueing, disk scheduler. ++ * ++ * Based on ideas and code from CFQ: ++ * Copyright (C) 2003 Jens Axboe ++ * ++ * Copyright (C) 2008 Fabio Checconi ++ * Paolo Valente ++ * ++ * Copyright (C) 2010 Paolo Valente ++ * ++ * Licensed under the GPL-2 as detailed in the accompanying COPYING.BFQ file. ++ * ++ * BFQ is a proportional share disk scheduling algorithm based on the ++ * slice-by-slice service scheme of CFQ. But BFQ assigns budgets, ++ * measured in number of sectors, to tasks instead of time slices. ++ * The disk is not granted to the active task for a given time slice, ++ * but until it has exahusted its assigned budget. This change from ++ * the time to the service domain allows BFQ to distribute the disk ++ * bandwidth among tasks as desired, without any distortion due to ++ * ZBR, workload fluctuations or other factors. BFQ uses an ad hoc ++ * internal scheduler, called B-WF2Q+, to schedule tasks according to ++ * their budgets. Thanks to this accurate scheduler, BFQ can afford ++ * to assign high budgets to disk-bound non-seeky tasks (to boost the ++ * throughput), and yet guarantee low latencies to interactive and ++ * soft real-time applications. ++ * ++ * BFQ has been introduced in [1], where the interested reader can ++ * find an accurate description of the algorithm, the bandwidth ++ * distribution and latency guarantees it provides, plus formal proofs ++ * of all the properties. With respect to the algorithm presented in ++ * the paper, this implementation adds several little heuristics, and ++ * a hierarchical extension, based on H-WF2Q+. ++ * ++ * B-WF2Q+ is based on WF2Q+, that is described in [2], together with ++ * H-WF2Q+, while the augmented tree used to implement B-WF2Q+ with O(log N) ++ * complexity derives from the one introduced with EEVDF in [3]. ++ * ++ * [1] P. Valente and F. Checconi, ``High Throughput Disk Scheduling ++ * with Deterministic Guarantees on Bandwidth Distribution,'', ++ * IEEE Transactions on Computer, May 2010. ++ * ++ * http://algo.ing.unimo.it/people/paolo/disk_sched/bfq-techreport.pdf ++ * ++ * [2] Jon C.R. Bennett and H. Zhang, ``Hierarchical Packet Fair Queueing ++ * Algorithms,'' IEEE/ACM Transactions on Networking, 5(5):675-689, ++ * Oct 1997. ++ * ++ * http://www.cs.cmu.edu/~hzhang/papers/TON-97-Oct.ps.gz ++ * ++ * [3] I. Stoica and H. Abdel-Wahab, ``Earliest Eligible Virtual Deadline ++ * First: A Flexible and Accurate Mechanism for Proportional Share ++ * Resource Allocation,'' technical report. ++ * ++ * http://www.cs.berkeley.edu/~istoica/papers/eevdf-tr-95.pdf ++ */ ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include "bfq.h" ++#include "blk.h" ++ ++/* Max number of dispatches in one round of service. */ ++static const int bfq_quantum = 4; ++ ++/* Expiration time of sync (0) and async (1) requests, in jiffies. */ ++static const int bfq_fifo_expire[2] = { HZ / 4, HZ / 8 }; ++ ++/* Maximum backwards seek, in KiB. */ ++static const int bfq_back_max = 16 * 1024; ++ ++/* Penalty of a backwards seek, in number of sectors. */ ++static const int bfq_back_penalty = 2; ++ ++/* Idling period duration, in jiffies. */ ++static int bfq_slice_idle = HZ / 125; ++ ++/* Default maximum budget values, in sectors and number of requests. */ ++static const int bfq_default_max_budget = 16 * 1024; ++static const int bfq_max_budget_async_rq = 4; ++ ++/* ++ * Async to sync throughput distribution is controlled as follows: ++ * when an async request is served, the entity is charged the number ++ * of sectors of the request, multipled by the factor below ++ */ ++static const int bfq_async_charge_factor = 10; ++ ++/* Default timeout values, in jiffies, approximating CFQ defaults. */ ++static const int bfq_timeout_sync = HZ / 8; ++static int bfq_timeout_async = HZ / 25; ++ ++struct kmem_cache *bfq_pool; ++ ++/* Below this threshold (in ms), we consider thinktime immediate. */ ++#define BFQ_MIN_TT 2 ++ ++/* hw_tag detection: parallel requests threshold and min samples needed. */ ++#define BFQ_HW_QUEUE_THRESHOLD 4 ++#define BFQ_HW_QUEUE_SAMPLES 32 ++ ++#define BFQQ_SEEK_THR (sector_t)(8 * 1024) ++#define BFQQ_SEEKY(bfqq) ((bfqq)->seek_mean > BFQQ_SEEK_THR) ++ ++/* Min samples used for peak rate estimation (for autotuning). */ ++#define BFQ_PEAK_RATE_SAMPLES 32 ++ ++/* Shift used for peak rate fixed precision calculations. */ ++#define BFQ_RATE_SHIFT 16 ++ ++/* ++ * The duration of the weight raising for interactive applications is ++ * computed automatically (as default behaviour), using the following ++ * formula: duration = (R / r) * T, where r is the peak rate of the ++ * disk, and R and T are two reference parameters. In particular, R is ++ * the peak rate of a reference disk, and T is about the maximum time ++ * for starting popular large applications on that disk, under BFQ and ++ * while reading two files in parallel. Finally, BFQ uses two ++ * different pairs (R, T) depending on whether the disk is rotational ++ * or non-rotational. ++ */ ++#define T_rot (msecs_to_jiffies(5500)) ++#define T_nonrot (msecs_to_jiffies(2000)) ++/* Next two quantities are in sectors/usec, left-shifted by BFQ_RATE_SHIFT */ ++#define R_rot 17415 ++#define R_nonrot 34791 ++ ++#define BFQ_SERVICE_TREE_INIT ((struct bfq_service_tree) \ ++ { RB_ROOT, RB_ROOT, NULL, NULL, 0, 0 }) ++ ++#define RQ_BIC(rq) ((struct bfq_io_cq *) (rq)->elv.priv[0]) ++#define RQ_BFQQ(rq) ((rq)->elv.priv[1]) ++ ++static inline void bfq_schedule_dispatch(struct bfq_data *bfqd); ++ ++#include "bfq-ioc.c" ++#include "bfq-sched.c" ++#include "bfq-cgroup.c" ++ ++#define bfq_class_idle(bfqq) ((bfqq)->entity.ioprio_class ==\ ++ IOPRIO_CLASS_IDLE) ++#define bfq_class_rt(bfqq) ((bfqq)->entity.ioprio_class ==\ ++ IOPRIO_CLASS_RT) ++ ++#define bfq_sample_valid(samples) ((samples) > 80) ++ ++/* ++ * We regard a request as SYNC, if either it's a read or has the SYNC bit ++ * set (in which case it could also be a direct WRITE). ++ */ ++static inline int bfq_bio_sync(struct bio *bio) ++{ ++ if (bio_data_dir(bio) == READ || (bio->bi_rw & REQ_SYNC)) ++ return 1; ++ ++ return 0; ++} ++ ++/* ++ * Scheduler run of queue, if there are requests pending and no one in the ++ * driver that will restart queueing. ++ */ ++static inline void bfq_schedule_dispatch(struct bfq_data *bfqd) ++{ ++ if (bfqd->queued != 0) { ++ bfq_log(bfqd, "schedule dispatch"); ++ kblockd_schedule_work(bfqd->queue, &bfqd->unplug_work); ++ } ++} ++ ++/* ++ * Lifted from AS - choose which of rq1 and rq2 that is best served now. ++ * We choose the request that is closesr to the head right now. Distance ++ * behind the head is penalized and only allowed to a certain extent. ++ */ ++static struct request *bfq_choose_req(struct bfq_data *bfqd, ++ struct request *rq1, ++ struct request *rq2, ++ sector_t last) ++{ ++ sector_t s1, s2, d1 = 0, d2 = 0; ++ unsigned long back_max; ++#define BFQ_RQ1_WRAP 0x01 /* request 1 wraps */ ++#define BFQ_RQ2_WRAP 0x02 /* request 2 wraps */ ++ unsigned wrap = 0; /* bit mask: requests behind the disk head? */ ++ ++ if (rq1 == NULL || rq1 == rq2) ++ return rq2; ++ if (rq2 == NULL) ++ return rq1; ++ ++ if (rq_is_sync(rq1) && !rq_is_sync(rq2)) ++ return rq1; ++ else if (rq_is_sync(rq2) && !rq_is_sync(rq1)) ++ return rq2; ++ if ((rq1->cmd_flags & REQ_META) && !(rq2->cmd_flags & REQ_META)) ++ return rq1; ++ else if ((rq2->cmd_flags & REQ_META) && !(rq1->cmd_flags & REQ_META)) ++ return rq2; ++ ++ s1 = blk_rq_pos(rq1); ++ s2 = blk_rq_pos(rq2); ++ ++ /* ++ * By definition, 1KiB is 2 sectors. ++ */ ++ back_max = bfqd->bfq_back_max * 2; ++ ++ /* ++ * Strict one way elevator _except_ in the case where we allow ++ * short backward seeks which are biased as twice the cost of a ++ * similar forward seek. ++ */ ++ if (s1 >= last) ++ d1 = s1 - last; ++ else if (s1 + back_max >= last) ++ d1 = (last - s1) * bfqd->bfq_back_penalty; ++ else ++ wrap |= BFQ_RQ1_WRAP; ++ ++ if (s2 >= last) ++ d2 = s2 - last; ++ else if (s2 + back_max >= last) ++ d2 = (last - s2) * bfqd->bfq_back_penalty; ++ else ++ wrap |= BFQ_RQ2_WRAP; ++ ++ /* Found required data */ ++ ++ /* ++ * By doing switch() on the bit mask "wrap" we avoid having to ++ * check two variables for all permutations: --> faster! ++ */ ++ switch (wrap) { ++ case 0: /* common case for CFQ: rq1 and rq2 not wrapped */ ++ if (d1 < d2) ++ return rq1; ++ else if (d2 < d1) ++ return rq2; ++ else { ++ if (s1 >= s2) ++ return rq1; ++ else ++ return rq2; ++ } ++ ++ case BFQ_RQ2_WRAP: ++ return rq1; ++ case BFQ_RQ1_WRAP: ++ return rq2; ++ case (BFQ_RQ1_WRAP|BFQ_RQ2_WRAP): /* both rqs wrapped */ ++ default: ++ /* ++ * Since both rqs are wrapped, ++ * start with the one that's further behind head ++ * (--> only *one* back seek required), ++ * since back seek takes more time than forward. ++ */ ++ if (s1 <= s2) ++ return rq1; ++ else ++ return rq2; ++ } ++} ++ ++static struct bfq_queue * ++bfq_rq_pos_tree_lookup(struct bfq_data *bfqd, struct rb_root *root, ++ sector_t sector, struct rb_node **ret_parent, ++ struct rb_node ***rb_link) ++{ ++ struct rb_node **p, *parent; ++ struct bfq_queue *bfqq = NULL; ++ ++ parent = NULL; ++ p = &root->rb_node; ++ while (*p) { ++ struct rb_node **n; ++ ++ parent = *p; ++ bfqq = rb_entry(parent, struct bfq_queue, pos_node); ++ ++ /* ++ * Sort strictly based on sector. Smallest to the left, ++ * largest to the right. ++ */ ++ if (sector > blk_rq_pos(bfqq->next_rq)) ++ n = &(*p)->rb_right; ++ else if (sector < blk_rq_pos(bfqq->next_rq)) ++ n = &(*p)->rb_left; ++ else ++ break; ++ p = n; ++ bfqq = NULL; ++ } ++ ++ *ret_parent = parent; ++ if (rb_link) ++ *rb_link = p; ++ ++ bfq_log(bfqd, "rq_pos_tree_lookup %llu: returning %d", ++ (long long unsigned)sector, ++ bfqq != NULL ? bfqq->pid : 0); ++ ++ return bfqq; ++} ++ ++static void bfq_rq_pos_tree_add(struct bfq_data *bfqd, struct bfq_queue *bfqq) ++{ ++ struct rb_node **p, *parent; ++ struct bfq_queue *__bfqq; ++ ++ if (bfqq->pos_root != NULL) { ++ rb_erase(&bfqq->pos_node, bfqq->pos_root); ++ bfqq->pos_root = NULL; ++ } ++ ++ if (bfq_class_idle(bfqq)) ++ return; ++ if (!bfqq->next_rq) ++ return; ++ ++ bfqq->pos_root = &bfqd->rq_pos_tree; ++ __bfqq = bfq_rq_pos_tree_lookup(bfqd, bfqq->pos_root, ++ blk_rq_pos(bfqq->next_rq), &parent, &p); ++ if (__bfqq == NULL) { ++ rb_link_node(&bfqq->pos_node, parent, p); ++ rb_insert_color(&bfqq->pos_node, bfqq->pos_root); ++ } else ++ bfqq->pos_root = NULL; ++} ++ ++static struct request *bfq_find_next_rq(struct bfq_data *bfqd, ++ struct bfq_queue *bfqq, ++ struct request *last) ++{ ++ struct rb_node *rbnext = rb_next(&last->rb_node); ++ struct rb_node *rbprev = rb_prev(&last->rb_node); ++ struct request *next = NULL, *prev = NULL; ++ ++ BUG_ON(RB_EMPTY_NODE(&last->rb_node)); ++ ++ if (rbprev != NULL) ++ prev = rb_entry_rq(rbprev); ++ ++ if (rbnext != NULL) ++ next = rb_entry_rq(rbnext); ++ else { ++ rbnext = rb_first(&bfqq->sort_list); ++ if (rbnext && rbnext != &last->rb_node) ++ next = rb_entry_rq(rbnext); ++ } ++ ++ return bfq_choose_req(bfqd, next, prev, blk_rq_pos(last)); ++} ++ ++static void bfq_del_rq_rb(struct request *rq) ++{ ++ struct bfq_queue *bfqq = RQ_BFQQ(rq); ++ struct bfq_data *bfqd = bfqq->bfqd; ++ const int sync = rq_is_sync(rq); ++ ++ BUG_ON(bfqq->queued[sync] == 0); ++ bfqq->queued[sync]--; ++ bfqd->queued--; ++ ++ elv_rb_del(&bfqq->sort_list, rq); ++ ++ if (RB_EMPTY_ROOT(&bfqq->sort_list)) { ++ if (bfq_bfqq_busy(bfqq) && bfqq != bfqd->active_queue) ++ bfq_del_bfqq_busy(bfqd, bfqq, 1); ++ /* ++ * Remove queue from request-position tree as it is empty. ++ */ ++ if (bfqq->pos_root != NULL) { ++ rb_erase(&bfqq->pos_node, bfqq->pos_root); ++ bfqq->pos_root = NULL; ++ } ++ } ++} ++ ++/* see the definition of bfq_async_charge_factor for details */ ++static inline unsigned long bfq_serv_to_charge(struct request *rq, ++ struct bfq_queue *bfqq) ++{ ++ return blk_rq_sectors(rq) * ++ (1 + ((!bfq_bfqq_sync(bfqq)) * (bfqq->raising_coeff == 1) * ++ bfq_async_charge_factor)); ++} ++ ++/** ++ * bfq_updated_next_req - update the queue after a new next_rq selection. ++ * @bfqd: the device data the queue belongs to. ++ * @bfqq: the queue to update. ++ * ++ * If the first request of a queue changes we make sure that the queue ++ * has enough budget to serve at least its first request (if the ++ * request has grown). We do this because if the queue has not enough ++ * budget for its first request, it has to go through two dispatch ++ * rounds to actually get it dispatched. ++ */ ++static void bfq_updated_next_req(struct bfq_data *bfqd, ++ struct bfq_queue *bfqq) ++{ ++ struct bfq_entity *entity = &bfqq->entity; ++ struct bfq_service_tree *st = bfq_entity_service_tree(entity); ++ struct request *next_rq = bfqq->next_rq; ++ unsigned long new_budget; ++ ++ if (next_rq == NULL) ++ return; ++ ++ if (bfqq == bfqd->active_queue) ++ /* ++ * In order not to break guarantees, budgets cannot be ++ * changed after an entity has been selected. ++ */ ++ return; ++ ++ BUG_ON(entity->tree != &st->active); ++ BUG_ON(entity == entity->sched_data->active_entity); ++ ++ new_budget = max_t(unsigned long, bfqq->max_budget, ++ bfq_serv_to_charge(next_rq, bfqq)); ++ entity->budget = new_budget; ++ bfq_log_bfqq(bfqd, bfqq, "updated next rq: new budget %lu", new_budget); ++ bfq_activate_bfqq(bfqd, bfqq); ++} ++ ++static inline unsigned int bfq_wrais_duration(struct bfq_data *bfqd) ++{ ++ u64 dur; ++ ++ if (bfqd->bfq_raising_max_time > 0) ++ return bfqd->bfq_raising_max_time; ++ ++ dur = bfqd->RT_prod; ++ do_div(dur, bfqd->peak_rate); ++ ++ return dur; ++} ++ ++static inline void ++bfq_bfqq_resume_state(struct bfq_queue *bfqq, struct bfq_io_cq *bic) ++{ ++ if (bic->saved_idle_window) ++ bfq_mark_bfqq_idle_window(bfqq); ++ else ++ bfq_clear_bfqq_idle_window(bfqq); ++ if (bic->raising_time_left) { ++ /* ++ * Start a weight raising period with the duration given by ++ * the raising_time_left snapshot. ++ */ ++ bfqq->raising_coeff = bfqq->bfqd->bfq_raising_coeff; ++ bfqq->raising_cur_max_time = bic->raising_time_left; ++ bfqq->last_rais_start_finish = jiffies; ++ } ++} ++ ++/* ++ * Must be called with the queue_lock held. ++ */ ++static int bfqq_process_refs(struct bfq_queue *bfqq) ++{ ++ int process_refs, io_refs; ++ ++ io_refs = bfqq->allocated[READ] + bfqq->allocated[WRITE]; ++ process_refs = atomic_read(&bfqq->ref) - io_refs - bfqq->entity.on_st; ++ BUG_ON(process_refs < 0); ++ return process_refs; ++} ++ ++static void bfq_add_rq_rb(struct request *rq) ++{ ++ struct bfq_queue *bfqq = RQ_BFQQ(rq); ++ struct bfq_entity *entity = &bfqq->entity; ++ struct bfq_data *bfqd = bfqq->bfqd; ++ struct request *next_rq, *prev; ++ unsigned long old_raising_coeff = bfqq->raising_coeff; ++ int idle_for_long_time = bfqq->budget_timeout + ++ bfqd->bfq_raising_min_idle_time < jiffies; ++ ++ bfq_log_bfqq(bfqd, bfqq, "add_rq_rb %d", rq_is_sync(rq)); ++ bfqq->queued[rq_is_sync(rq)]++; ++ bfqd->queued++; ++ ++ elv_rb_add(&bfqq->sort_list, rq); ++ ++ /* ++ * Check if this request is a better next-serve candidate. ++ */ ++ prev = bfqq->next_rq; ++ next_rq = bfq_choose_req(bfqd, bfqq->next_rq, rq, bfqd->last_position); ++ BUG_ON(next_rq == NULL); ++ bfqq->next_rq = next_rq; ++ ++ /* ++ * Adjust priority tree position, if next_rq changes. ++ */ ++ if (prev != bfqq->next_rq) ++ bfq_rq_pos_tree_add(bfqd, bfqq); ++ ++ if (!bfq_bfqq_busy(bfqq)) { ++ int soft_rt = bfqd->bfq_raising_max_softrt_rate > 0 && ++ bfqq->soft_rt_next_start < jiffies; ++ entity->budget = max_t(unsigned long, bfqq->max_budget, ++ bfq_serv_to_charge(next_rq, bfqq)); ++ ++ if (! bfqd->low_latency) ++ goto add_bfqq_busy; ++ ++ if (bfq_bfqq_just_split(bfqq)) ++ goto set_ioprio_changed; ++ ++ /* ++ * If the queue: ++ * - is not being boosted, ++ * - has been idle for enough time, ++ * - is not a sync queue or is linked to a bfq_io_cq (it is ++ * shared "for its nature" or it is not shared and its ++ * requests have not been redirected to a shared queue) ++ * start a weight-raising period. ++ */ ++ if(old_raising_coeff == 1 && (idle_for_long_time || soft_rt) && ++ (!bfq_bfqq_sync(bfqq) || bfqq->bic != NULL)) { ++ bfqq->raising_coeff = bfqd->bfq_raising_coeff; ++ if (idle_for_long_time) ++ bfqq->raising_cur_max_time = ++ bfq_wrais_duration(bfqd); ++ else ++ bfqq->raising_cur_max_time = ++ bfqd->bfq_raising_rt_max_time; ++ bfq_log_bfqq(bfqd, bfqq, ++ "wrais starting at %llu msec," ++ "rais_max_time %u", ++ bfqq->last_rais_start_finish, ++ jiffies_to_msecs(bfqq-> ++ raising_cur_max_time)); ++ } else if (old_raising_coeff > 1) { ++ if (idle_for_long_time) ++ bfqq->raising_cur_max_time = ++ bfq_wrais_duration(bfqd); ++ else if (bfqq->raising_cur_max_time == ++ bfqd->bfq_raising_rt_max_time && ++ !soft_rt) { ++ bfqq->raising_coeff = 1; ++ bfq_log_bfqq(bfqd, bfqq, ++ "wrais ending at %llu msec," ++ "rais_max_time %u", ++ bfqq->last_rais_start_finish, ++ jiffies_to_msecs(bfqq-> ++ raising_cur_max_time)); ++ } ++ } ++set_ioprio_changed: ++ if (old_raising_coeff != bfqq->raising_coeff) ++ entity->ioprio_changed = 1; ++add_bfqq_busy: ++ bfq_add_bfqq_busy(bfqd, bfqq); ++ } else { ++ if(bfqd->low_latency && old_raising_coeff == 1 && ++ !rq_is_sync(rq) && ++ bfqq->last_rais_start_finish + ++ bfqd->bfq_raising_min_inter_arr_async < jiffies) { ++ bfqq->raising_coeff = bfqd->bfq_raising_coeff; ++ bfqq->raising_cur_max_time = bfq_wrais_duration(bfqd); ++ ++ entity->ioprio_changed = 1; ++ bfq_log_bfqq(bfqd, bfqq, ++ "non-idle wrais starting at %llu msec," ++ "rais_max_time %u", ++ bfqq->last_rais_start_finish, ++ jiffies_to_msecs(bfqq-> ++ raising_cur_max_time)); ++ } ++ bfq_updated_next_req(bfqd, bfqq); ++ } ++ ++ if(bfqd->low_latency && ++ (old_raising_coeff == 1 || bfqq->raising_coeff == 1 || ++ idle_for_long_time)) ++ bfqq->last_rais_start_finish = jiffies; ++} ++ ++static void bfq_reposition_rq_rb(struct bfq_queue *bfqq, struct request *rq) ++{ ++ elv_rb_del(&bfqq->sort_list, rq); ++ bfqq->queued[rq_is_sync(rq)]--; ++ bfqq->bfqd->queued--; ++ bfq_add_rq_rb(rq); ++} ++ ++static struct request *bfq_find_rq_fmerge(struct bfq_data *bfqd, ++ struct bio *bio) ++{ ++ struct task_struct *tsk = current; ++ struct bfq_io_cq *bic; ++ struct bfq_queue *bfqq; ++ ++ bic = bfq_bic_lookup(bfqd, tsk->io_context); ++ if (bic == NULL) ++ return NULL; ++ ++ bfqq = bic_to_bfqq(bic, bfq_bio_sync(bio)); ++ if (bfqq != NULL) { ++ sector_t sector = bio->bi_sector + bio_sectors(bio); ++ ++ return elv_rb_find(&bfqq->sort_list, sector); ++ } ++ ++ return NULL; ++} ++ ++static void bfq_activate_request(struct request_queue *q, struct request *rq) ++{ ++ struct bfq_data *bfqd = q->elevator->elevator_data; ++ ++ bfqd->rq_in_driver++; ++ bfqd->last_position = blk_rq_pos(rq) + blk_rq_sectors(rq); ++ bfq_log(bfqd, "activate_request: new bfqd->last_position %llu", ++ (long long unsigned)bfqd->last_position); ++} ++ ++static void bfq_deactivate_request(struct request_queue *q, struct request *rq) ++{ ++ struct bfq_data *bfqd = q->elevator->elevator_data; ++ ++ WARN_ON(bfqd->rq_in_driver == 0); ++ bfqd->rq_in_driver--; ++} ++ ++static void bfq_remove_request(struct request *rq) ++{ ++ struct bfq_queue *bfqq = RQ_BFQQ(rq); ++ struct bfq_data *bfqd = bfqq->bfqd; ++ ++ if (bfqq->next_rq == rq) { ++ bfqq->next_rq = bfq_find_next_rq(bfqd, bfqq, rq); ++ bfq_updated_next_req(bfqd, bfqq); ++ } ++ ++ list_del_init(&rq->queuelist); ++ bfq_del_rq_rb(rq); ++ ++ if (rq->cmd_flags & REQ_META) { ++ WARN_ON(bfqq->meta_pending == 0); ++ bfqq->meta_pending--; ++ } ++} ++ ++static int bfq_merge(struct request_queue *q, struct request **req, ++ struct bio *bio) ++{ ++ struct bfq_data *bfqd = q->elevator->elevator_data; ++ struct request *__rq; ++ ++ __rq = bfq_find_rq_fmerge(bfqd, bio); ++ if (__rq != NULL && elv_rq_merge_ok(__rq, bio)) { ++ *req = __rq; ++ return ELEVATOR_FRONT_MERGE; ++ } ++ ++ return ELEVATOR_NO_MERGE; ++} ++ ++static void bfq_merged_request(struct request_queue *q, struct request *req, ++ int type) ++{ ++ if (type == ELEVATOR_FRONT_MERGE) { ++ struct bfq_queue *bfqq = RQ_BFQQ(req); ++ ++ bfq_reposition_rq_rb(bfqq, req); ++ } ++} ++ ++static void bfq_merged_requests(struct request_queue *q, struct request *rq, ++ struct request *next) ++{ ++ struct bfq_queue *bfqq = RQ_BFQQ(rq); ++ ++ /* ++ * Reposition in fifo if next is older than rq. ++ */ ++ if (!list_empty(&rq->queuelist) && !list_empty(&next->queuelist) && ++ time_before(rq_fifo_time(next), rq_fifo_time(rq))) { ++ list_move(&rq->queuelist, &next->queuelist); ++ rq_set_fifo_time(rq, rq_fifo_time(next)); ++ } ++ ++ if (bfqq->next_rq == next) ++ bfqq->next_rq = rq; ++ ++ bfq_remove_request(next); ++} ++ ++static inline sector_t bfq_io_struct_pos(void *io_struct, bool request) ++{ ++ if (request) ++ return blk_rq_pos(io_struct); ++ else ++ return ((struct bio *)io_struct)->bi_sector; ++} ++ ++static inline sector_t bfq_dist_from(sector_t pos1, ++ sector_t pos2) ++{ ++ if (pos1 >= pos2) ++ return pos1 - pos2; ++ else ++ return pos2 - pos1; ++} ++ ++static inline int bfq_rq_close_to_sector(void *io_struct, bool request, ++ sector_t sector) ++{ ++ return bfq_dist_from(bfq_io_struct_pos(io_struct, request), sector) <= ++ BFQQ_SEEK_THR; ++} ++ ++static struct bfq_queue *bfqq_close(struct bfq_data *bfqd, sector_t sector) ++{ ++ struct rb_root *root = &bfqd->rq_pos_tree; ++ struct rb_node *parent, *node; ++ struct bfq_queue *__bfqq; ++ ++ if (RB_EMPTY_ROOT(root)) ++ return NULL; ++ ++ /* ++ * First, if we find a request starting at the end of the last ++ * request, choose it. ++ */ ++ __bfqq = bfq_rq_pos_tree_lookup(bfqd, root, sector, &parent, NULL); ++ if (__bfqq != NULL) ++ return __bfqq; ++ ++ /* ++ * If the exact sector wasn't found, the parent of the NULL leaf ++ * will contain the closest sector (rq_pos_tree sorted by next_request ++ * position). ++ */ ++ __bfqq = rb_entry(parent, struct bfq_queue, pos_node); ++ if (bfq_rq_close_to_sector(__bfqq->next_rq, true, sector)) ++ return __bfqq; ++ ++ if (blk_rq_pos(__bfqq->next_rq) < sector) ++ node = rb_next(&__bfqq->pos_node); ++ else ++ node = rb_prev(&__bfqq->pos_node); ++ if (node == NULL) ++ return NULL; ++ ++ __bfqq = rb_entry(node, struct bfq_queue, pos_node); ++ if (bfq_rq_close_to_sector(__bfqq->next_rq, true, sector)) ++ return __bfqq; ++ ++ return NULL; ++} ++ ++/* ++ * bfqd - obvious ++ * cur_bfqq - passed in so that we don't decide that the current queue ++ * is closely cooperating with itself ++ * sector - used as a reference point to search for a close queue ++ */ ++static struct bfq_queue *bfq_close_cooperator(struct bfq_data *bfqd, ++ struct bfq_queue *cur_bfqq, ++ sector_t sector) ++{ ++ struct bfq_queue *bfqq; ++ ++ if (bfq_class_idle(cur_bfqq)) ++ return NULL; ++ if (!bfq_bfqq_sync(cur_bfqq)) ++ return NULL; ++ if (BFQQ_SEEKY(cur_bfqq)) ++ return NULL; ++ ++ /* If device has only one backlogged bfq_queue, don't search. */ ++ if (bfqd->busy_queues == 1) ++ return NULL; ++ ++ /* ++ * We should notice if some of the queues are cooperating, e.g. ++ * working closely on the same area of the disk. In that case, ++ * we can group them together and don't waste time idling. ++ */ ++ bfqq = bfqq_close(bfqd, sector); ++ if (bfqq == NULL || bfqq == cur_bfqq) ++ return NULL; ++ ++ /* ++ * Do not merge queues from different bfq_groups. ++ */ ++ if (bfqq->entity.parent != cur_bfqq->entity.parent) ++ return NULL; ++ ++ /* ++ * It only makes sense to merge sync queues. ++ */ ++ if (!bfq_bfqq_sync(bfqq)) ++ return NULL; ++ if (BFQQ_SEEKY(bfqq)) ++ return NULL; ++ ++ /* ++ * Do not merge queues of different priority classes. ++ */ ++ if (bfq_class_rt(bfqq) != bfq_class_rt(cur_bfqq)) ++ return NULL; ++ ++ return bfqq; ++} ++ ++static struct bfq_queue * ++bfq_setup_merge(struct bfq_queue *bfqq, struct bfq_queue *new_bfqq) ++{ ++ int process_refs, new_process_refs; ++ struct bfq_queue *__bfqq; ++ ++ /* ++ * If there are no process references on the new_bfqq, then it is ++ * unsafe to follow the ->new_bfqq chain as other bfqq's in the chain ++ * may have dropped their last reference (not just their last process ++ * reference). ++ */ ++ if (!bfqq_process_refs(new_bfqq)) ++ return NULL; ++ ++ /* Avoid a circular list and skip interim queue merges. */ ++ while ((__bfqq = new_bfqq->new_bfqq)) { ++ if (__bfqq == bfqq) ++ return NULL; ++ new_bfqq = __bfqq; ++ } ++ ++ process_refs = bfqq_process_refs(bfqq); ++ new_process_refs = bfqq_process_refs(new_bfqq); ++ /* ++ * If the process for the bfqq has gone away, there is no ++ * sense in merging the queues. ++ */ ++ if (process_refs == 0 || new_process_refs == 0) ++ return NULL; ++ ++ bfq_log_bfqq(bfqq->bfqd, bfqq, "scheduling merge with queue %d", ++ new_bfqq->pid); ++ ++ /* ++ * Merging is just a redirection: the requests of the process owning ++ * one of the two queues are redirected to the other queue. The latter ++ * queue, in its turn, is set as shared if this is the first time that ++ * the requests of some process are redirected to it. ++ * ++ * We redirect bfqq to new_bfqq and not the opposite, because we ++ * are in the context of the process owning bfqq, hence we have the ++ * io_cq of this process. So we can immediately configure this io_cq ++ * to redirect the requests of the process to new_bfqq. ++ * ++ * NOTE, even if new_bfqq coincides with the active queue, the io_cq of ++ * new_bfqq is not available, because, if the active queue is shared, ++ * bfqd->active_bic may not point to the io_cq of the active queue. ++ * Redirecting the requests of the process owning bfqq to the currently ++ * active queue is in any case the best option, as we feed the active queue ++ * with new requests close to the last request served and, by doing so, ++ * hopefully increase the throughput. ++ */ ++ bfqq->new_bfqq = new_bfqq; ++ atomic_add(process_refs, &new_bfqq->ref); ++ return new_bfqq; ++} ++ ++/* ++ * Attempt to schedule a merge of bfqq with the currently active queue or ++ * with a close queue among the scheduled queues. ++ * Return NULL if no merge was scheduled, a pointer to the shared bfq_queue ++ * structure otherwise. ++ */ ++static struct bfq_queue * ++bfq_setup_cooperator(struct bfq_data *bfqd, struct bfq_queue *bfqq, ++ void *io_struct, bool request) ++{ ++ struct bfq_queue *active_bfqq, *new_bfqq; ++ ++ if (bfqq->new_bfqq) ++ return bfqq->new_bfqq; ++ ++ if (!io_struct) ++ return NULL; ++ ++ active_bfqq = bfqd->active_queue; ++ ++ if (active_bfqq == NULL || active_bfqq == bfqq || !bfqd->active_bic) ++ goto check_scheduled; ++ ++ if (bfq_class_idle(active_bfqq) || bfq_class_idle(bfqq)) ++ goto check_scheduled; ++ ++ if (bfq_class_rt(active_bfqq) != bfq_class_rt(bfqq)) ++ goto check_scheduled; ++ ++ if (active_bfqq->entity.parent != bfqq->entity.parent) ++ goto check_scheduled; ++ ++ if (bfq_rq_close_to_sector(io_struct, request, bfqd->last_position) && ++ bfq_bfqq_sync(active_bfqq) && bfq_bfqq_sync(bfqq)) ++ if ((new_bfqq = bfq_setup_merge(bfqq, active_bfqq))) ++ return new_bfqq; /* Merge with the active queue */ ++ ++ /* ++ * Check whether there is a cooperator among currently scheduled ++ * queues. The only thing we need is that the bio/request is not ++ * NULL, as we need it to establish whether a cooperator exists. ++ */ ++check_scheduled: ++ new_bfqq = bfq_close_cooperator(bfqd, bfqq, ++ bfq_io_struct_pos(io_struct, request)); ++ if (new_bfqq) ++ return bfq_setup_merge(bfqq, new_bfqq); ++ ++ return NULL; ++} ++ ++static inline void ++bfq_bfqq_save_state(struct bfq_queue *bfqq) ++{ ++ /* ++ * If bfqq->bic == NULL, the queue is already shared or its requests ++ * have already been redirected to a shared queue; both idle window ++ * and weight raising state have already been saved. Do nothing. ++ */ ++ if (bfqq->bic == NULL) ++ return; ++ if (bfqq->raising_coeff > 1) { ++ unsigned long wrais_duration = ++ jiffies - bfqq->last_rais_start_finish; ++ /* ++ * It may happen that a queue's weight raising period lasts ++ * longer than its raising_cur_max_time, as weight raising is ++ * handled only when a request is enqueued or dispatched (it ++ * does not use any timer). If the weight raising period is ++ * about to end, don't save it. ++ */ ++ if (bfqq->raising_cur_max_time <= wrais_duration) ++ bfqq->bic->raising_time_left = 0; ++ else ++ bfqq->bic->raising_time_left = ++ bfqq->raising_cur_max_time - wrais_duration; ++ /* ++ * The bfq_queue is becoming shared or the requests of the ++ * process owning the queue are being redirected to a shared ++ * queue. Stop the weight raising period of the queue, as in ++ * both cases it should not be owned by an interactive or soft ++ * real-time application. ++ */ ++ bfqq->raising_coeff = 1; ++ bfqq->entity.ioprio_changed = 1; ++ } else ++ bfqq->bic->raising_time_left = 0; ++ bfqq->bic->saved_idle_window = bfq_bfqq_idle_window(bfqq); ++} ++ ++static inline void ++bfq_get_bic_reference(struct bfq_queue *bfqq) ++{ ++ /* ++ * If bfqq->bic has a non-NULL value, the bic to which it belongs ++ * is about to begin using a shared bfq_queue. ++ */ ++ if (bfqq->bic) ++ atomic_long_inc(&bfqq->bic->icq.ioc->refcount); ++} ++ ++static void ++bfq_merge_bfqqs(struct bfq_data *bfqd, struct bfq_io_cq *bic, ++ struct bfq_queue *bfqq, struct bfq_queue *new_bfqq) ++{ ++ bfq_log_bfqq(bfqd, bfqq, "merging with queue %lu", ++ (long unsigned)new_bfqq->pid); ++ /* Save weight raising and idle window of the merged queues */ ++ bfq_bfqq_save_state(bfqq); ++ bfq_bfqq_save_state(new_bfqq); ++ /* ++ * Grab a reference to the bic, to prevent it from being destroyed ++ * before being possibly touched by a bfq_split_bfqq(). ++ */ ++ bfq_get_bic_reference(bfqq); ++ bfq_get_bic_reference(new_bfqq); ++ /* Merge queues (that is, let bic redirect its requests to new_bfqq) */ ++ bic_set_bfqq(bic, new_bfqq, 1); ++ bfq_mark_bfqq_coop(new_bfqq); ++ /* ++ * new_bfqq now belongs to at least two bics (it is a shared queue): set ++ * new_bfqq->bic to NULL. bfqq either: ++ * - does not belong to any bic any more, and hence bfqq->bic must ++ * be set to NULL, or ++ * - is a queue whose owning bics have already been redirected to a ++ * different queue, hence the queue is destined to not belong to any ++ * bic soon and bfqq->bic is already NULL (therefore the next ++ * assignment causes no harm). ++ */ ++ new_bfqq->bic = NULL; ++ bfqq->bic = NULL; ++ bfq_put_queue(bfqq); ++} ++ ++static int bfq_allow_merge(struct request_queue *q, struct request *rq, ++ struct bio *bio) ++{ ++ struct bfq_data *bfqd = q->elevator->elevator_data; ++ struct bfq_io_cq *bic; ++ struct bfq_queue *bfqq, *new_bfqq; ++ ++ /* ++ * Disallow merge of a sync bio into an async request. ++ */ ++ if (bfq_bio_sync(bio) && !rq_is_sync(rq)) ++ return 0; ++ ++ /* ++ * Lookup the bfqq that this bio will be queued with. Allow ++ * merge only if rq is queued there. ++ * Queue lock is held here. ++ */ ++ bic = bfq_bic_lookup(bfqd, current->io_context); ++ if (bic == NULL) ++ return 0; ++ ++ bfqq = bic_to_bfqq(bic, bfq_bio_sync(bio)); ++ /* ++ * We take advantage of this function to perform an early merge ++ * of the queues of possible cooperating processes. ++ */ ++ if (bfqq != NULL && ++ (new_bfqq = bfq_setup_cooperator(bfqd, bfqq, bio, false))) { ++ bfq_merge_bfqqs(bfqd, bic, bfqq, new_bfqq); ++ /* ++ * If we get here, the bio will be queued in the shared queue, ++ * i.e., new_bfqq, so use new_bfqq to decide whether bio and ++ * rq can be merged. ++ */ ++ bfqq = new_bfqq; ++ } ++ ++ return bfqq == RQ_BFQQ(rq); ++} ++ ++static void __bfq_set_active_queue(struct bfq_data *bfqd, ++ struct bfq_queue *bfqq) ++{ ++ if (bfqq != NULL) { ++ bfq_mark_bfqq_must_alloc(bfqq); ++ bfq_mark_bfqq_budget_new(bfqq); ++ bfq_clear_bfqq_fifo_expire(bfqq); ++ ++ bfqd->budgets_assigned = (bfqd->budgets_assigned*7 + 256) / 8; ++ ++ bfq_log_bfqq(bfqd, bfqq, "set_active_queue, cur-budget = %lu", ++ bfqq->entity.budget); ++ } ++ ++ bfqd->active_queue = bfqq; ++} ++ ++/* ++ * Get and set a new active queue for service. ++ */ ++static struct bfq_queue *bfq_set_active_queue(struct bfq_data *bfqd) ++{ ++ struct bfq_queue *bfqq = bfq_get_next_queue(bfqd); ++ ++ __bfq_set_active_queue(bfqd, bfqq); ++ return bfqq; ++} ++ ++/* ++ * If enough samples have been computed, return the current max budget ++ * stored in bfqd, which is dynamically updated according to the ++ * estimated disk peak rate; otherwise return the default max budget ++ */ ++static inline unsigned long bfq_max_budget(struct bfq_data *bfqd) ++{ ++ if (bfqd->budgets_assigned < 194) ++ return bfq_default_max_budget; ++ else ++ return bfqd->bfq_max_budget; ++} ++ ++/* ++ * Return min budget, which is a fraction of the current or default ++ * max budget (trying with 1/32) ++ */ ++static inline unsigned long bfq_min_budget(struct bfq_data *bfqd) ++{ ++ if (bfqd->budgets_assigned < 194) ++ return bfq_default_max_budget / 32; ++ else ++ return bfqd->bfq_max_budget / 32; ++} ++ ++/* ++ * Decides whether idling should be done for given device and ++ * given active queue. ++ */ ++static inline bool bfq_queue_nonrot_noidle(struct bfq_data *bfqd, ++ struct bfq_queue *active_bfqq) ++{ ++ if (active_bfqq == NULL) ++ return false; ++ /* ++ * If device is SSD it has no seek penalty, disable idling; but ++ * do so only if: ++ * - device does not support queuing, otherwise we still have ++ * a problem with sync vs async workloads; ++ * - the queue is not weight-raised, to preserve guarantees. ++ */ ++ return (blk_queue_nonrot(bfqd->queue) && bfqd->hw_tag && ++ active_bfqq->raising_coeff == 1); ++} ++ ++static void bfq_arm_slice_timer(struct bfq_data *bfqd) ++{ ++ struct bfq_queue *bfqq = bfqd->active_queue; ++ struct bfq_io_cq *bic; ++ unsigned long sl; ++ ++ WARN_ON(!RB_EMPTY_ROOT(&bfqq->sort_list)); ++ ++ if (bfq_queue_nonrot_noidle(bfqd, bfqq)) ++ return; ++ ++ /* Idling is disabled, either manually or by past process history. */ ++ if (bfqd->bfq_slice_idle == 0 || !bfq_bfqq_idle_window(bfqq)) ++ return; ++ ++ /* Tasks have exited, don't wait. */ ++ bic = bfqd->active_bic; ++ if (bic == NULL || atomic_read(&bic->icq.ioc->active_ref) == 0) ++ return; ++ ++ bfq_mark_bfqq_wait_request(bfqq); ++ ++ /* ++ * We don't want to idle for seeks, but we do want to allow ++ * fair distribution of slice time for a process doing back-to-back ++ * seeks. So allow a little bit of time for him to submit a new rq. ++ * ++ * To prevent processes with (partly) seeky workloads from ++ * being too ill-treated, grant them a small fraction of the ++ * assigned budget before reducing the waiting time to ++ * BFQ_MIN_TT. This happened to help reduce latency. ++ */ ++ sl = bfqd->bfq_slice_idle; ++ if (bfq_sample_valid(bfqq->seek_samples) && BFQQ_SEEKY(bfqq) && ++ bfqq->entity.service > bfq_max_budget(bfqd) / 8 && ++ bfqq->raising_coeff == 1) ++ sl = min(sl, msecs_to_jiffies(BFQ_MIN_TT)); ++ else if (bfqq->raising_coeff > 1) ++ sl = sl * 3; ++ bfqd->last_idling_start = ktime_get(); ++ mod_timer(&bfqd->idle_slice_timer, jiffies + sl); ++ bfq_log(bfqd, "arm idle: %u/%u ms", ++ jiffies_to_msecs(sl), jiffies_to_msecs(bfqd->bfq_slice_idle)); ++} ++ ++/* ++ * Set the maximum time for the active queue to consume its ++ * budget. This prevents seeky processes from lowering the disk ++ * throughput (always guaranteed with a time slice scheme as in CFQ). ++ */ ++static void bfq_set_budget_timeout(struct bfq_data *bfqd) ++{ ++ struct bfq_queue *bfqq = bfqd->active_queue; ++ unsigned int timeout_coeff; ++ if (bfqq->raising_cur_max_time == bfqd->bfq_raising_rt_max_time) ++ timeout_coeff = 1; ++ else ++ timeout_coeff = bfqq->entity.weight / bfqq->entity.orig_weight; ++ ++ bfqd->last_budget_start = ktime_get(); ++ ++ bfq_clear_bfqq_budget_new(bfqq); ++ bfqq->budget_timeout = jiffies + ++ bfqd->bfq_timeout[bfq_bfqq_sync(bfqq)] * timeout_coeff; ++ ++ bfq_log_bfqq(bfqd, bfqq, "set budget_timeout %u", ++ jiffies_to_msecs(bfqd->bfq_timeout[bfq_bfqq_sync(bfqq)] * ++ timeout_coeff)); ++} ++ ++/* ++ * Move request from internal lists to the request queue dispatch list. ++ */ ++static void bfq_dispatch_insert(struct request_queue *q, struct request *rq) ++{ ++ struct bfq_data *bfqd = q->elevator->elevator_data; ++ struct bfq_queue *bfqq = RQ_BFQQ(rq); ++ ++ bfq_remove_request(rq); ++ bfqq->dispatched++; ++ elv_dispatch_sort(q, rq); ++ ++ if (bfq_bfqq_sync(bfqq)) ++ bfqd->sync_flight++; ++} ++ ++/* ++ * Return expired entry, or NULL to just start from scratch in rbtree. ++ */ ++static struct request *bfq_check_fifo(struct bfq_queue *bfqq) ++{ ++ struct request *rq = NULL; ++ ++ if (bfq_bfqq_fifo_expire(bfqq)) ++ return NULL; ++ ++ bfq_mark_bfqq_fifo_expire(bfqq); ++ ++ if (list_empty(&bfqq->fifo)) ++ return NULL; ++ ++ rq = rq_entry_fifo(bfqq->fifo.next); ++ ++ if (time_before(jiffies, rq_fifo_time(rq))) ++ return NULL; ++ ++ return rq; ++} ++ ++static inline unsigned long bfq_bfqq_budget_left(struct bfq_queue *bfqq) ++{ ++ struct bfq_entity *entity = &bfqq->entity; ++ return entity->budget - entity->service; ++} ++ ++static void __bfq_bfqq_expire(struct bfq_data *bfqd, struct bfq_queue *bfqq) ++{ ++ BUG_ON(bfqq != bfqd->active_queue); ++ ++ __bfq_bfqd_reset_active(bfqd); ++ ++ if (RB_EMPTY_ROOT(&bfqq->sort_list)) { ++ bfq_del_bfqq_busy(bfqd, bfqq, 1); ++ /* ++ * overloading budget_timeout field to store when ++ * the queue remains with no backlog, used by ++ * the weight-raising mechanism ++ */ ++ bfqq->budget_timeout = jiffies ; ++ } else { ++ bfq_activate_bfqq(bfqd, bfqq); ++ /* ++ * Resort priority tree of potential close cooperators. ++ */ ++ bfq_rq_pos_tree_add(bfqd, bfqq); ++ } ++ ++ /* ++ * If this bfqq is shared between multiple processes, check ++ * to make sure that those processes are still issuing I/Os ++ * within the mean seek distance. If not, it may be time to ++ * break the queues apart again. ++ */ ++ if (bfq_bfqq_coop(bfqq) && BFQQ_SEEKY(bfqq)) ++ bfq_mark_bfqq_split_coop(bfqq); ++} ++ ++/** ++ * __bfq_bfqq_recalc_budget - try to adapt the budget to the @bfqq behavior. ++ * @bfqd: device data. ++ * @bfqq: queue to update. ++ * @reason: reason for expiration. ++ * ++ * Handle the feedback on @bfqq budget. See the body for detailed ++ * comments. ++ */ ++static void __bfq_bfqq_recalc_budget(struct bfq_data *bfqd, ++ struct bfq_queue *bfqq, ++ enum bfqq_expiration reason) ++{ ++ struct request *next_rq; ++ unsigned long budget, min_budget; ++ ++ budget = bfqq->max_budget; ++ min_budget = bfq_min_budget(bfqd); ++ ++ BUG_ON(bfqq != bfqd->active_queue); ++ ++ bfq_log_bfqq(bfqd, bfqq, "recalc_budg: last budg %lu, budg left %lu", ++ bfqq->entity.budget, bfq_bfqq_budget_left(bfqq)); ++ bfq_log_bfqq(bfqd, bfqq, "recalc_budg: last max_budg %lu, min budg %lu", ++ budget, bfq_min_budget(bfqd)); ++ bfq_log_bfqq(bfqd, bfqq, "recalc_budg: sync %d, seeky %d", ++ bfq_bfqq_sync(bfqq), BFQQ_SEEKY(bfqd->active_queue)); ++ ++ if (bfq_bfqq_sync(bfqq)) { ++ switch (reason) { ++ /* ++ * Caveat: in all the following cases we trade latency ++ * for throughput. ++ */ ++ case BFQ_BFQQ_TOO_IDLE: ++ /* ++ * This is the only case where we may reduce ++ * the budget: if there is no requets of the ++ * process still waiting for completion, then ++ * we assume (tentatively) that the timer has ++ * expired because the batch of requests of ++ * the process could have been served with a ++ * smaller budget. Hence, betting that ++ * process will behave in the same way when it ++ * becomes backlogged again, we reduce its ++ * next budget. As long as we guess right, ++ * this budget cut reduces the latency ++ * experienced by the process. ++ * ++ * However, if there are still outstanding ++ * requests, then the process may have not yet ++ * issued its next request just because it is ++ * still waiting for the completion of some of ++ * the still oustanding ones. So in this ++ * subcase we do not reduce its budget, on the ++ * contrary we increase it to possibly boost ++ * the throughput, as discussed in the ++ * comments to the BUDGET_TIMEOUT case. ++ */ ++ if (bfqq->dispatched > 0) /* still oustanding reqs */ ++ budget = min(budget * 2, bfqd->bfq_max_budget); ++ else { ++ if (budget > 5 * min_budget) ++ budget -= 4 * min_budget; ++ else ++ budget = min_budget; ++ } ++ break; ++ case BFQ_BFQQ_BUDGET_TIMEOUT: ++ /* ++ * We double the budget here because: 1) it ++ * gives the chance to boost the throughput if ++ * this is not a seeky process (which may have ++ * bumped into this timeout because of, e.g., ++ * ZBR), 2) together with charge_full_budget ++ * it helps give seeky processes higher ++ * timestamps, and hence be served less ++ * frequently. ++ */ ++ budget = min(budget * 2, bfqd->bfq_max_budget); ++ break; ++ case BFQ_BFQQ_BUDGET_EXHAUSTED: ++ /* ++ * The process still has backlog, and did not ++ * let either the budget timeout or the disk ++ * idling timeout expire. Hence it is not ++ * seeky, has a short thinktime and may be ++ * happy with a higher budget too. So ++ * definitely increase the budget of this good ++ * candidate to boost the disk throughput. ++ */ ++ budget = min(budget * 4, bfqd->bfq_max_budget); ++ break; ++ case BFQ_BFQQ_NO_MORE_REQUESTS: ++ /* ++ * Leave the budget unchanged. ++ */ ++ default: ++ return; ++ } ++ } else /* async queue */ ++ /* async queues get always the maximum possible budget ++ * (their ability to dispatch is limited by ++ * @bfqd->bfq_max_budget_async_rq). ++ */ ++ budget = bfqd->bfq_max_budget; ++ ++ bfqq->max_budget = budget; ++ ++ if (bfqd->budgets_assigned >= 194 && bfqd->bfq_user_max_budget == 0 && ++ bfqq->max_budget > bfqd->bfq_max_budget) ++ bfqq->max_budget = bfqd->bfq_max_budget; ++ ++ /* ++ * Make sure that we have enough budget for the next request. ++ * Since the finish time of the bfqq must be kept in sync with ++ * the budget, be sure to call __bfq_bfqq_expire() after the ++ * update. ++ */ ++ next_rq = bfqq->next_rq; ++ if (next_rq != NULL) ++ bfqq->entity.budget = max_t(unsigned long, bfqq->max_budget, ++ bfq_serv_to_charge(next_rq, bfqq)); ++ else ++ bfqq->entity.budget = bfqq->max_budget; ++ ++ bfq_log_bfqq(bfqd, bfqq, "head sect: %u, new budget %lu", ++ next_rq != NULL ? blk_rq_sectors(next_rq) : 0, ++ bfqq->entity.budget); ++} ++ ++static unsigned long bfq_calc_max_budget(u64 peak_rate, u64 timeout) ++{ ++ unsigned long max_budget; ++ ++ /* ++ * The max_budget calculated when autotuning is equal to the ++ * amount of sectors transfered in timeout_sync at the ++ * estimated peak rate. ++ */ ++ max_budget = (unsigned long)(peak_rate * 1000 * ++ timeout >> BFQ_RATE_SHIFT); ++ ++ return max_budget; ++} ++ ++/* ++ * In addition to updating the peak rate, checks whether the process ++ * is "slow", and returns 1 if so. This slow flag is used, in addition ++ * to the budget timeout, to reduce the amount of service provided to ++ * seeky processes, and hence reduce their chances to lower the ++ * throughput. See the code for more details. ++ */ ++static int bfq_update_peak_rate(struct bfq_data *bfqd, struct bfq_queue *bfqq, ++ int compensate, enum bfqq_expiration reason) ++{ ++ u64 bw, usecs, expected, timeout; ++ ktime_t delta; ++ int update = 0; ++ ++ if (!bfq_bfqq_sync(bfqq) || bfq_bfqq_budget_new(bfqq)) ++ return 0; ++ ++ if (compensate) ++ delta = bfqd->last_idling_start; ++ else ++ delta = ktime_get(); ++ delta = ktime_sub(delta, bfqd->last_budget_start); ++ usecs = ktime_to_us(delta); ++ ++ /* Don't trust short/unrealistic values. */ ++ if (usecs < 100 || usecs >= LONG_MAX) ++ return 0; ++ ++ /* ++ * Calculate the bandwidth for the last slice. We use a 64 bit ++ * value to store the peak rate, in sectors per usec in fixed ++ * point math. We do so to have enough precision in the estimate ++ * and to avoid overflows. ++ */ ++ bw = (u64)bfqq->entity.service << BFQ_RATE_SHIFT; ++ do_div(bw, (unsigned long)usecs); ++ ++ timeout = jiffies_to_msecs(bfqd->bfq_timeout[BLK_RW_SYNC]); ++ ++ /* ++ * Use only long (> 20ms) intervals to filter out spikes for ++ * the peak rate estimation. ++ */ ++ if (usecs > 20000) { ++ if (bw > bfqd->peak_rate || ++ (!BFQQ_SEEKY(bfqq) && ++ reason == BFQ_BFQQ_BUDGET_TIMEOUT)) { ++ bfq_log(bfqd, "measured bw =%llu", bw); ++ /* ++ * To smooth oscillations use a low-pass filter with ++ * alpha=7/8, i.e., ++ * new_rate = (7/8) * old_rate + (1/8) * bw ++ */ ++ do_div(bw, 8); ++ if (bw == 0) ++ return 0; ++ bfqd->peak_rate *= 7; ++ do_div(bfqd->peak_rate, 8); ++ bfqd->peak_rate += bw; ++ update = 1; ++ bfq_log(bfqd, "new peak_rate=%llu", bfqd->peak_rate); ++ } ++ ++ update |= bfqd->peak_rate_samples == BFQ_PEAK_RATE_SAMPLES - 1; ++ ++ if (bfqd->peak_rate_samples < BFQ_PEAK_RATE_SAMPLES) ++ bfqd->peak_rate_samples++; ++ ++ if (bfqd->peak_rate_samples == BFQ_PEAK_RATE_SAMPLES && ++ update && bfqd->bfq_user_max_budget == 0) { ++ bfqd->bfq_max_budget = ++ bfq_calc_max_budget(bfqd->peak_rate, timeout); ++ bfq_log(bfqd, "new max_budget=%lu", ++ bfqd->bfq_max_budget); ++ } ++ } ++ ++ /* ++ * If the process has been served for a too short time ++ * interval to let its possible sequential accesses prevail on ++ * the initial seek time needed to move the disk head on the ++ * first sector it requested, then give the process a chance ++ * and for the moment return false. ++ */ ++ if (bfqq->entity.budget <= bfq_max_budget(bfqd) / 8) ++ return 0; ++ ++ /* ++ * A process is considered ``slow'' (i.e., seeky, so that we ++ * cannot treat it fairly in the service domain, as it would ++ * slow down too much the other processes) if, when a slice ++ * ends for whatever reason, it has received service at a ++ * rate that would not be high enough to complete the budget ++ * before the budget timeout expiration. ++ */ ++ expected = bw * 1000 * timeout >> BFQ_RATE_SHIFT; ++ ++ /* ++ * Caveat: processes doing IO in the slower disk zones will ++ * tend to be slow(er) even if not seeky. And the estimated ++ * peak rate will actually be an average over the disk ++ * surface. Hence, to not be too harsh with unlucky processes, ++ * we keep a budget/3 margin of safety before declaring a ++ * process slow. ++ */ ++ return expected > (4 * bfqq->entity.budget) / 3; ++} ++ ++/** ++ * bfq_bfqq_expire - expire a queue. ++ * @bfqd: device owning the queue. ++ * @bfqq: the queue to expire. ++ * @compensate: if true, compensate for the time spent idling. ++ * @reason: the reason causing the expiration. ++ * ++ * ++ * If the process associated to the queue is slow (i.e., seeky), or in ++ * case of budget timeout, or, finally, if it is async, we ++ * artificially charge it an entire budget (independently of the ++ * actual service it received). As a consequence, the queue will get ++ * higher timestamps than the correct ones upon reactivation, and ++ * hence it will be rescheduled as if it had received more service ++ * than what it actually received. In the end, this class of processes ++ * will receive less service in proportion to how slowly they consume ++ * their budgets (and hence how seriously they tend to lower the ++ * throughput). ++ * ++ * In contrast, when a queue expires because it has been idling for ++ * too much or because it exhausted its budget, we do not touch the ++ * amount of service it has received. Hence when the queue will be ++ * reactivated and its timestamps updated, the latter will be in sync ++ * with the actual service received by the queue until expiration. ++ * ++ * Charging a full budget to the first type of queues and the exact ++ * service to the others has the effect of using the WF2Q+ policy to ++ * schedule the former on a timeslice basis, without violating the ++ * service domain guarantees of the latter. ++ */ ++static void bfq_bfqq_expire(struct bfq_data *bfqd, ++ struct bfq_queue *bfqq, ++ int compensate, ++ enum bfqq_expiration reason) ++{ ++ int slow; ++ BUG_ON(bfqq != bfqd->active_queue); ++ ++ /* Update disk peak rate for autotuning and check whether the ++ * process is slow (see bfq_update_peak_rate). ++ */ ++ slow = bfq_update_peak_rate(bfqd, bfqq, compensate, reason); ++ ++ /* ++ * As above explained, 'punish' slow (i.e., seeky), timed-out ++ * and async queues, to favor sequential sync workloads. ++ * ++ * Processes doing IO in the slower disk zones will tend to be ++ * slow(er) even if not seeky. Hence, since the estimated peak ++ * rate is actually an average over the disk surface, these ++ * processes may timeout just for bad luck. To avoid punishing ++ * them we do not charge a full budget to a process that ++ * succeeded in consuming at least 2/3 of its budget. ++ */ ++ if (slow || (reason == BFQ_BFQQ_BUDGET_TIMEOUT && ++ bfq_bfqq_budget_left(bfqq) >= bfqq->entity.budget / 3)) ++ bfq_bfqq_charge_full_budget(bfqq); ++ ++ if (bfqd->low_latency && bfqq->raising_coeff == 1) ++ bfqq->last_rais_start_finish = jiffies; ++ ++ if (bfqd->low_latency && bfqd->bfq_raising_max_softrt_rate > 0) { ++ if(reason != BFQ_BFQQ_BUDGET_TIMEOUT) ++ bfqq->soft_rt_next_start = ++ jiffies + ++ HZ * bfqq->entity.service / ++ bfqd->bfq_raising_max_softrt_rate; ++ else ++ bfqq->soft_rt_next_start = -1; /* infinity */ ++ } ++ bfq_log_bfqq(bfqd, bfqq, ++ "expire (%d, slow %d, num_disp %d, idle_win %d)", reason, slow, ++ bfqq->dispatched, bfq_bfqq_idle_window(bfqq)); ++ ++ /* Increase, decrease or leave budget unchanged according to reason */ ++ __bfq_bfqq_recalc_budget(bfqd, bfqq, reason); ++ __bfq_bfqq_expire(bfqd, bfqq); ++} ++ ++/* ++ * Budget timeout is not implemented through a dedicated timer, but ++ * just checked on request arrivals and completions, as well as on ++ * idle timer expirations. ++ */ ++static int bfq_bfqq_budget_timeout(struct bfq_queue *bfqq) ++{ ++ if (bfq_bfqq_budget_new(bfqq)) ++ return 0; ++ ++ if (time_before(jiffies, bfqq->budget_timeout)) ++ return 0; ++ ++ return 1; ++} ++ ++/* ++ * If we expire a queue that is waiting for the arrival of a new ++ * request, we may prevent the fictitious timestamp backshifting that ++ * allows the guarantees of the queue to be preserved (see [1] for ++ * this tricky aspect). Hence we return true only if this condition ++ * does not hold, or if the queue is slow enough to deserve only to be ++ * kicked off for preserving a high throughput. ++*/ ++static inline int bfq_may_expire_for_budg_timeout(struct bfq_queue *bfqq) ++{ ++ bfq_log_bfqq(bfqq->bfqd, bfqq, ++ "may_budget_timeout: wr %d left %d timeout %d", ++ bfq_bfqq_wait_request(bfqq), ++ bfq_bfqq_budget_left(bfqq) >= bfqq->entity.budget / 3, ++ bfq_bfqq_budget_timeout(bfqq)); ++ ++ return (!bfq_bfqq_wait_request(bfqq) || ++ bfq_bfqq_budget_left(bfqq) >= bfqq->entity.budget / 3) ++ && ++ bfq_bfqq_budget_timeout(bfqq); ++} ++ ++/* ++ * Select a queue for service. If we have a current active queue, ++ * check whether to continue servicing it, or retrieve and set a new one. ++ */ ++static struct bfq_queue *bfq_select_queue(struct bfq_data *bfqd) ++{ ++ struct bfq_queue *bfqq; ++ struct request *next_rq; ++ enum bfqq_expiration reason = BFQ_BFQQ_BUDGET_TIMEOUT; ++ ++ bfqq = bfqd->active_queue; ++ if (bfqq == NULL) ++ goto new_queue; ++ ++ bfq_log_bfqq(bfqd, bfqq, "select_queue: already active queue"); ++ ++ if (bfq_may_expire_for_budg_timeout(bfqq)) ++ goto expire; ++ ++ next_rq = bfqq->next_rq; ++ /* ++ * If bfqq has requests queued and it has enough budget left to ++ * serve them, keep the queue, otherwise expire it. ++ */ ++ if (next_rq != NULL) { ++ if (bfq_serv_to_charge(next_rq, bfqq) > ++ bfq_bfqq_budget_left(bfqq)) { ++ reason = BFQ_BFQQ_BUDGET_EXHAUSTED; ++ goto expire; ++ } else { ++ /* ++ * The idle timer may be pending because we may not ++ * disable disk idling even when a new request arrives ++ */ ++ if (timer_pending(&bfqd->idle_slice_timer)) { ++ /* ++ * If we get here: 1) at least a new request ++ * has arrived but we have not disabled the ++ * timer because the request was too small, ++ * 2) then the block layer has unplugged the ++ * device, causing the dispatch to be invoked. ++ * ++ * Since the device is unplugged, now the ++ * requests are probably large enough to ++ * provide a reasonable throughput. ++ * So we disable idling. ++ */ ++ bfq_clear_bfqq_wait_request(bfqq); ++ del_timer(&bfqd->idle_slice_timer); ++ } ++ goto keep_queue; ++ } ++ } ++ ++ /* ++ * No requests pending. If there is no cooperator, and the active ++ * queue still has requests in flight or is idling for a new request, ++ * then keep it. ++ */ ++ if (timer_pending(&bfqd->idle_slice_timer) || ++ (bfqq->dispatched != 0 && bfq_bfqq_idle_window(bfqq) && ++ !bfq_queue_nonrot_noidle(bfqd, bfqq))) { ++ bfqq = NULL; ++ goto keep_queue; ++ } ++ ++ reason = BFQ_BFQQ_NO_MORE_REQUESTS; ++expire: ++ bfq_bfqq_expire(bfqd, bfqq, 0, reason); ++new_queue: ++ bfqq = bfq_set_active_queue(bfqd); ++ bfq_log(bfqd, "select_queue: new queue %d returned", ++ bfqq != NULL ? bfqq->pid : 0); ++keep_queue: ++ return bfqq; ++} ++ ++static void update_raising_data(struct bfq_data *bfqd, struct bfq_queue *bfqq) ++{ ++ struct bfq_entity *entity = &bfqq->entity; ++ if (bfqq->raising_coeff > 1) { /* queue is being boosted */ ++ bfq_log_bfqq(bfqd, bfqq, ++ "raising period dur %u/%u msec, " ++ "old raising coeff %u, w %d(%d)", ++ jiffies_to_msecs(jiffies - ++ bfqq->last_rais_start_finish), ++ jiffies_to_msecs(bfqq->raising_cur_max_time), ++ bfqq->raising_coeff, ++ bfqq->entity.weight, bfqq->entity.orig_weight); ++ ++ BUG_ON(bfqq != bfqd->active_queue && entity->weight != ++ entity->orig_weight * bfqq->raising_coeff); ++ if(entity->ioprio_changed) ++ bfq_log_bfqq(bfqd, bfqq, ++ "WARN: pending prio change"); ++ /* ++ * If too much time has elapsed from the beginning ++ * of this weight-raising period and process is not soft ++ * real-time, stop it ++ */ ++ if (jiffies - bfqq->last_rais_start_finish > ++ bfqq->raising_cur_max_time) { ++ int soft_rt = bfqd->bfq_raising_max_softrt_rate > 0 && ++ bfqq->soft_rt_next_start < jiffies; ++ ++ bfqq->last_rais_start_finish = jiffies; ++ if (soft_rt) ++ bfqq->raising_cur_max_time = ++ bfqd->bfq_raising_rt_max_time; ++ else { ++ bfq_log_bfqq(bfqd, bfqq, ++ "wrais ending at %llu msec," ++ "rais_max_time %u", ++ bfqq->last_rais_start_finish, ++ jiffies_to_msecs(bfqq-> ++ raising_cur_max_time)); ++ bfqq->raising_coeff = 1; ++ entity->ioprio_changed = 1; ++ } ++ } ++ } ++ /* Update weight both if it must be raised and if it must be lowered */ ++ if ((entity->weight > entity->orig_weight) != (bfqq->raising_coeff > 1)) ++ __bfq_entity_update_weight_prio( ++ bfq_entity_service_tree(entity), ++ entity); ++} ++ ++ ++/* ++ * Dispatch one request from bfqq, moving it to the request queue ++ * dispatch list. ++ */ ++static int bfq_dispatch_request(struct bfq_data *bfqd, ++ struct bfq_queue *bfqq) ++{ ++ int dispatched = 0; ++ struct request *rq; ++ unsigned long service_to_charge; ++ ++ BUG_ON(RB_EMPTY_ROOT(&bfqq->sort_list)); ++ ++ /* Follow expired path, else get first next available. */ ++ rq = bfq_check_fifo(bfqq); ++ if (rq == NULL) ++ rq = bfqq->next_rq; ++ service_to_charge = bfq_serv_to_charge(rq, bfqq); ++ ++ if (service_to_charge > bfq_bfqq_budget_left(bfqq)) { ++ /* ++ * This may happen if the next rq is chosen ++ * in fifo order instead of sector order. ++ * The budget is properly dimensioned ++ * to be always sufficient to serve the next request ++ * only if it is chosen in sector order. The reason is ++ * that it would be quite inefficient and little useful ++ * to always make sure that the budget is large enough ++ * to serve even the possible next rq in fifo order. ++ * In fact, requests are seldom served in fifo order. ++ * ++ * Expire the queue for budget exhaustion, and ++ * make sure that the next act_budget is enough ++ * to serve the next request, even if it comes ++ * from the fifo expired path. ++ */ ++ bfqq->next_rq = rq; ++ /* ++ * Since this dispatch is failed, make sure that ++ * a new one will be performed ++ */ ++ if (!bfqd->rq_in_driver) ++ bfq_schedule_dispatch(bfqd); ++ goto expire; ++ } ++ ++ /* Finally, insert request into driver dispatch list. */ ++ bfq_bfqq_served(bfqq, service_to_charge); ++ bfq_dispatch_insert(bfqd->queue, rq); ++ ++ update_raising_data(bfqd, bfqq); ++ ++ bfq_log_bfqq(bfqd, bfqq, "dispatched %u sec req (%llu), " ++ "budg left %lu", ++ blk_rq_sectors(rq), ++ (long long unsigned)blk_rq_pos(rq), ++ bfq_bfqq_budget_left(bfqq)); ++ ++ dispatched++; ++ ++ if (bfqd->active_bic == NULL) { ++ atomic_long_inc(&RQ_BIC(rq)->icq.ioc->refcount); ++ bfqd->active_bic = RQ_BIC(rq); ++ } ++ ++ if (bfqd->busy_queues > 1 && ((!bfq_bfqq_sync(bfqq) && ++ dispatched >= bfqd->bfq_max_budget_async_rq) || ++ bfq_class_idle(bfqq))) ++ goto expire; ++ ++ return dispatched; ++ ++expire: ++ bfq_bfqq_expire(bfqd, bfqq, 0, BFQ_BFQQ_BUDGET_EXHAUSTED); ++ return dispatched; ++} ++ ++static int __bfq_forced_dispatch_bfqq(struct bfq_queue *bfqq) ++{ ++ int dispatched = 0; ++ ++ while (bfqq->next_rq != NULL) { ++ bfq_dispatch_insert(bfqq->bfqd->queue, bfqq->next_rq); ++ dispatched++; ++ } ++ ++ BUG_ON(!list_empty(&bfqq->fifo)); ++ return dispatched; ++} ++ ++/* ++ * Drain our current requests. Used for barriers and when switching ++ * io schedulers on-the-fly. ++ */ ++static int bfq_forced_dispatch(struct bfq_data *bfqd) ++{ ++ struct bfq_queue *bfqq, *n; ++ struct bfq_service_tree *st; ++ int dispatched = 0; ++ ++ bfqq = bfqd->active_queue; ++ if (bfqq != NULL) ++ __bfq_bfqq_expire(bfqd, bfqq); ++ ++ /* ++ * Loop through classes, and be careful to leave the scheduler ++ * in a consistent state, as feedback mechanisms and vtime ++ * updates cannot be disabled during the process. ++ */ ++ list_for_each_entry_safe(bfqq, n, &bfqd->active_list, bfqq_list) { ++ st = bfq_entity_service_tree(&bfqq->entity); ++ ++ dispatched += __bfq_forced_dispatch_bfqq(bfqq); ++ bfqq->max_budget = bfq_max_budget(bfqd); ++ ++ bfq_forget_idle(st); ++ } ++ ++ BUG_ON(bfqd->busy_queues != 0); ++ ++ return dispatched; ++} ++ ++static int bfq_dispatch_requests(struct request_queue *q, int force) ++{ ++ struct bfq_data *bfqd = q->elevator->elevator_data; ++ struct bfq_queue *bfqq; ++ int max_dispatch; ++ ++ bfq_log(bfqd, "dispatch requests: %d busy queues", bfqd->busy_queues); ++ if (bfqd->busy_queues == 0) ++ return 0; ++ ++ if (unlikely(force)) ++ return bfq_forced_dispatch(bfqd); ++ ++ if((bfqq = bfq_select_queue(bfqd)) == NULL) ++ return 0; ++ ++ max_dispatch = bfqd->bfq_quantum; ++ if (bfq_class_idle(bfqq)) ++ max_dispatch = 1; ++ ++ if (!bfq_bfqq_sync(bfqq)) ++ max_dispatch = bfqd->bfq_max_budget_async_rq; ++ ++ if (bfqq->dispatched >= max_dispatch) { ++ if (bfqd->busy_queues > 1) ++ return 0; ++ if (bfqq->dispatched >= 4 * max_dispatch) ++ return 0; ++ } ++ ++ if (bfqd->sync_flight != 0 && !bfq_bfqq_sync(bfqq)) ++ return 0; ++ ++ bfq_clear_bfqq_wait_request(bfqq); ++ BUG_ON(timer_pending(&bfqd->idle_slice_timer)); ++ ++ if (! bfq_dispatch_request(bfqd, bfqq)) ++ return 0; ++ ++ bfq_log_bfqq(bfqd, bfqq, "dispatched one request of %d" ++ "(max_disp %d)", bfqq->pid, max_dispatch); ++ ++ return 1; ++} ++ ++/* ++ * Task holds one reference to the queue, dropped when task exits. Each rq ++ * in-flight on this queue also holds a reference, dropped when rq is freed. ++ * ++ * Queue lock must be held here. ++ */ ++static void bfq_put_queue(struct bfq_queue *bfqq) ++{ ++ struct bfq_data *bfqd = bfqq->bfqd; ++ ++ BUG_ON(atomic_read(&bfqq->ref) <= 0); ++ ++ bfq_log_bfqq(bfqd, bfqq, "put_queue: %p %d", bfqq, ++ atomic_read(&bfqq->ref)); ++ if (!atomic_dec_and_test(&bfqq->ref)) ++ return; ++ ++ BUG_ON(rb_first(&bfqq->sort_list) != NULL); ++ BUG_ON(bfqq->allocated[READ] + bfqq->allocated[WRITE] != 0); ++ BUG_ON(bfqq->entity.tree != NULL); ++ BUG_ON(bfq_bfqq_busy(bfqq)); ++ BUG_ON(bfqd->active_queue == bfqq); ++ ++ bfq_log_bfqq(bfqd, bfqq, "put_queue: %p freed", bfqq); ++ ++ kmem_cache_free(bfq_pool, bfqq); ++} ++ ++static void bfq_put_cooperator(struct bfq_queue *bfqq) ++{ ++ struct bfq_queue *__bfqq, *next; ++ ++ /* ++ * If this queue was scheduled to merge with another queue, be ++ * sure to drop the reference taken on that queue (and others in ++ * the merge chain). See bfq_setup_merge and bfq_merge_bfqqs. ++ */ ++ __bfqq = bfqq->new_bfqq; ++ while (__bfqq) { ++ if (__bfqq == bfqq) { ++ WARN(1, "bfqq->new_bfqq loop detected.\n"); ++ break; ++ } ++ next = __bfqq->new_bfqq; ++ bfq_put_queue(__bfqq); ++ __bfqq = next; ++ } ++} ++ ++static void bfq_exit_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq) ++{ ++ if (bfqq == bfqd->active_queue) { ++ __bfq_bfqq_expire(bfqd, bfqq); ++ bfq_schedule_dispatch(bfqd); ++ } ++ ++ bfq_log_bfqq(bfqd, bfqq, "exit_bfqq: %p, %d", bfqq, ++ atomic_read(&bfqq->ref)); ++ ++ bfq_put_cooperator(bfqq); ++ ++ bfq_put_queue(bfqq); ++} ++ ++static void bfq_init_icq(struct io_cq *icq) ++{ ++ struct bfq_io_cq *bic = icq_to_bic(icq); ++ ++ bic->ttime.last_end_request = jiffies; ++ bic->raising_time_left = 0; ++} ++ ++static void bfq_exit_icq(struct io_cq *icq) ++{ ++ struct bfq_io_cq *bic = icq_to_bic(icq); ++ struct bfq_data *bfqd = bic_to_bfqd(bic); ++ ++ if (bic->bfqq[BLK_RW_ASYNC]) { ++ bfq_exit_bfqq(bfqd, bic->bfqq[BLK_RW_ASYNC]); ++ bic->bfqq[BLK_RW_ASYNC] = NULL; ++ } ++ ++ if (bic->bfqq[BLK_RW_SYNC]) { ++ /* ++ * If the bic is using a shared queue, put the reference ++ * taken on the io_context when the bic started using a ++ * shared bfq_queue. ++ */ ++ if (bfq_bfqq_coop(bic->bfqq[BLK_RW_SYNC])) ++ put_io_context(icq->ioc); ++ bfq_exit_bfqq(bfqd, bic->bfqq[BLK_RW_SYNC]); ++ bic->bfqq[BLK_RW_SYNC] = NULL; ++ } ++} ++ ++/* ++ * Update the entity prio values; note that the new values will not ++ * be used until the next (re)activation. ++ */ ++static void bfq_init_prio_data(struct bfq_queue *bfqq, struct bfq_io_cq *bic) ++{ ++ struct task_struct *tsk = current; ++ int ioprio_class; ++ ++ if (!bfq_bfqq_prio_changed(bfqq)) ++ return; ++ ++ ioprio_class = IOPRIO_PRIO_CLASS(bic->ioprio); ++ switch (ioprio_class) { ++ default: ++ printk(KERN_ERR "bfq: bad prio %x\n", ioprio_class); ++ case IOPRIO_CLASS_NONE: ++ /* ++ * No prio set, inherit CPU scheduling settings. ++ */ ++ bfqq->entity.new_ioprio = task_nice_ioprio(tsk); ++ bfqq->entity.new_ioprio_class = task_nice_ioclass(tsk); ++ break; ++ case IOPRIO_CLASS_RT: ++ bfqq->entity.new_ioprio = IOPRIO_PRIO_DATA(bic->ioprio); ++ bfqq->entity.new_ioprio_class = IOPRIO_CLASS_RT; ++ break; ++ case IOPRIO_CLASS_BE: ++ bfqq->entity.new_ioprio = IOPRIO_PRIO_DATA(bic->ioprio); ++ bfqq->entity.new_ioprio_class = IOPRIO_CLASS_BE; ++ break; ++ case IOPRIO_CLASS_IDLE: ++ bfqq->entity.new_ioprio_class = IOPRIO_CLASS_IDLE; ++ bfqq->entity.new_ioprio = 7; ++ bfq_clear_bfqq_idle_window(bfqq); ++ break; ++ } ++ ++ bfqq->entity.ioprio_changed = 1; ++ ++ /* ++ * Keep track of original prio settings in case we have to temporarily ++ * elevate the priority of this queue. ++ */ ++ bfqq->org_ioprio = bfqq->entity.new_ioprio; ++ bfq_clear_bfqq_prio_changed(bfqq); ++} ++ ++static void bfq_changed_ioprio(struct bfq_io_cq *bic) ++{ ++ struct bfq_data *bfqd; ++ struct bfq_queue *bfqq, *new_bfqq; ++ struct bfq_group *bfqg; ++ unsigned long uninitialized_var(flags); ++ int ioprio = bic->icq.ioc->ioprio; ++ ++ bfqd = bfq_get_bfqd_locked(&(bic->icq.q->elevator->elevator_data), &flags); ++ /* ++ * This condition may trigger on a newly created bic, be sure to drop the ++ * lock before returning. ++ */ ++ if (unlikely(bfqd == NULL) || likely(bic->ioprio == ioprio)) ++ goto out; ++ ++ bfqq = bic->bfqq[BLK_RW_ASYNC]; ++ if (bfqq != NULL) { ++ bfqg = container_of(bfqq->entity.sched_data, struct bfq_group, ++ sched_data); ++ new_bfqq = bfq_get_queue(bfqd, bfqg, BLK_RW_ASYNC, bic, ++ GFP_ATOMIC); ++ if (new_bfqq != NULL) { ++ bic->bfqq[BLK_RW_ASYNC] = new_bfqq; ++ bfq_log_bfqq(bfqd, bfqq, ++ "changed_ioprio: bfqq %p %d", ++ bfqq, atomic_read(&bfqq->ref)); ++ bfq_put_queue(bfqq); ++ } ++ } ++ ++ bfqq = bic->bfqq[BLK_RW_SYNC]; ++ if (bfqq != NULL) ++ bfq_mark_bfqq_prio_changed(bfqq); ++ ++ bic->ioprio = ioprio; ++ ++out: ++ bfq_put_bfqd_unlock(bfqd, &flags); ++} ++ ++static void bfq_init_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq, ++ pid_t pid, int is_sync) ++{ ++ RB_CLEAR_NODE(&bfqq->entity.rb_node); ++ INIT_LIST_HEAD(&bfqq->fifo); ++ ++ atomic_set(&bfqq->ref, 0); ++ bfqq->bfqd = bfqd; ++ ++ bfq_mark_bfqq_prio_changed(bfqq); ++ ++ if (is_sync) { ++ if (!bfq_class_idle(bfqq)) ++ bfq_mark_bfqq_idle_window(bfqq); ++ bfq_mark_bfqq_sync(bfqq); ++ } ++ ++ /* Tentative initial value to trade off between thr and lat */ ++ bfqq->max_budget = (2 * bfq_max_budget(bfqd)) / 3; ++ bfqq->pid = pid; ++ ++ bfqq->raising_coeff = 1; ++ bfqq->last_rais_start_finish = 0; ++ bfqq->soft_rt_next_start = -1; ++} ++ ++static struct bfq_queue *bfq_find_alloc_queue(struct bfq_data *bfqd, ++ struct bfq_group *bfqg, ++ int is_sync, ++ struct bfq_io_cq *bic, ++ gfp_t gfp_mask) ++{ ++ struct bfq_queue *bfqq, *new_bfqq = NULL; ++ ++retry: ++ /* bic always exists here */ ++ bfqq = bic_to_bfqq(bic, is_sync); ++ ++ /* ++ * Always try a new alloc if we fall back to the OOM bfqq ++ * originally, since it should just be a temporary situation. ++ */ ++ if (bfqq == NULL || bfqq == &bfqd->oom_bfqq) { ++ bfqq = NULL; ++ if (new_bfqq != NULL) { ++ bfqq = new_bfqq; ++ new_bfqq = NULL; ++ } else if (gfp_mask & __GFP_WAIT) { ++ spin_unlock_irq(bfqd->queue->queue_lock); ++ new_bfqq = kmem_cache_alloc_node(bfq_pool, ++ gfp_mask | __GFP_ZERO, ++ bfqd->queue->node); ++ spin_lock_irq(bfqd->queue->queue_lock); ++ if (new_bfqq != NULL) ++ goto retry; ++ } else { ++ bfqq = kmem_cache_alloc_node(bfq_pool, ++ gfp_mask | __GFP_ZERO, ++ bfqd->queue->node); ++ } ++ ++ if (bfqq != NULL) { ++ bfq_init_bfqq(bfqd, bfqq, current->pid, is_sync); ++ bfq_log_bfqq(bfqd, bfqq, "allocated"); ++ } else { ++ bfqq = &bfqd->oom_bfqq; ++ bfq_log_bfqq(bfqd, bfqq, "using oom bfqq"); ++ } ++ ++ bfq_init_prio_data(bfqq, bic); ++ bfq_init_entity(&bfqq->entity, bfqg); ++ } ++ ++ if (new_bfqq != NULL) ++ kmem_cache_free(bfq_pool, new_bfqq); ++ ++ return bfqq; ++} ++ ++static struct bfq_queue **bfq_async_queue_prio(struct bfq_data *bfqd, ++ struct bfq_group *bfqg, ++ int ioprio_class, int ioprio) ++{ ++ switch (ioprio_class) { ++ case IOPRIO_CLASS_RT: ++ return &bfqg->async_bfqq[0][ioprio]; ++ case IOPRIO_CLASS_NONE: ++ ioprio = IOPRIO_NORM; ++ /* fall through */ ++ case IOPRIO_CLASS_BE: ++ return &bfqg->async_bfqq[1][ioprio]; ++ case IOPRIO_CLASS_IDLE: ++ return &bfqg->async_idle_bfqq; ++ default: ++ BUG(); ++ } ++} ++ ++static struct bfq_queue *bfq_get_queue(struct bfq_data *bfqd, ++ struct bfq_group *bfqg, int is_sync, ++ struct bfq_io_cq *bic, gfp_t gfp_mask) ++{ ++ const int ioprio = IOPRIO_PRIO_DATA(bic->ioprio); ++ const int ioprio_class = IOPRIO_PRIO_CLASS(bic->ioprio); ++ struct bfq_queue **async_bfqq = NULL; ++ struct bfq_queue *bfqq = NULL; ++ ++ if (!is_sync) { ++ async_bfqq = bfq_async_queue_prio(bfqd, bfqg, ioprio_class, ++ ioprio); ++ bfqq = *async_bfqq; ++ } ++ ++ if (bfqq == NULL) ++ bfqq = bfq_find_alloc_queue(bfqd, bfqg, is_sync, bic, gfp_mask); ++ ++ /* ++ * Pin the queue now that it's allocated, scheduler exit will prune it. ++ */ ++ if (!is_sync && *async_bfqq == NULL) { ++ atomic_inc(&bfqq->ref); ++ bfq_log_bfqq(bfqd, bfqq, "get_queue, bfqq not in async: %p, %d", ++ bfqq, atomic_read(&bfqq->ref)); ++ *async_bfqq = bfqq; ++ } ++ ++ atomic_inc(&bfqq->ref); ++ bfq_log_bfqq(bfqd, bfqq, "get_queue, at end: %p, %d", bfqq, ++ atomic_read(&bfqq->ref)); ++ return bfqq; ++} ++ ++static void bfq_update_io_thinktime(struct bfq_data *bfqd, ++ struct bfq_io_cq *bic) ++{ ++ unsigned long elapsed = jiffies - bic->ttime.last_end_request; ++ unsigned long ttime = min(elapsed, 2UL * bfqd->bfq_slice_idle); ++ ++ bic->ttime.ttime_samples = (7*bic->ttime.ttime_samples + 256) / 8; ++ bic->ttime.ttime_total = (7*bic->ttime.ttime_total + 256*ttime) / 8; ++ bic->ttime.ttime_mean = (bic->ttime.ttime_total + 128) / bic->ttime.ttime_samples; ++} ++ ++static void bfq_update_io_seektime(struct bfq_data *bfqd, ++ struct bfq_queue *bfqq, ++ struct request *rq) ++{ ++ sector_t sdist; ++ u64 total; ++ ++ if (bfqq->last_request_pos < blk_rq_pos(rq)) ++ sdist = blk_rq_pos(rq) - bfqq->last_request_pos; ++ else ++ sdist = bfqq->last_request_pos - blk_rq_pos(rq); ++ ++ /* ++ * Don't allow the seek distance to get too large from the ++ * odd fragment, pagein, etc. ++ */ ++ if (bfqq->seek_samples == 0) /* first request, not really a seek */ ++ sdist = 0; ++ else if (bfqq->seek_samples <= 60) /* second & third seek */ ++ sdist = min(sdist, (bfqq->seek_mean * 4) + 2*1024*1024); ++ else ++ sdist = min(sdist, (bfqq->seek_mean * 4) + 2*1024*64); ++ ++ bfqq->seek_samples = (7*bfqq->seek_samples + 256) / 8; ++ bfqq->seek_total = (7*bfqq->seek_total + (u64)256*sdist) / 8; ++ total = bfqq->seek_total + (bfqq->seek_samples/2); ++ do_div(total, bfqq->seek_samples); ++ if (bfq_bfqq_coop(bfqq)) { ++ /* ++ * If the mean seektime increases for a (non-seeky) shared ++ * queue, some cooperator is likely to be idling too much. ++ * On the contrary, if it decreases, some cooperator has ++ * probably waked up. ++ * ++ */ ++ if ((sector_t)total < bfqq->seek_mean) ++ bfq_mark_bfqq_some_coop_idle(bfqq) ; ++ else if ((sector_t)total > bfqq->seek_mean) ++ bfq_clear_bfqq_some_coop_idle(bfqq) ; ++ } ++ bfqq->seek_mean = (sector_t)total; ++ ++ bfq_log_bfqq(bfqd, bfqq, "dist=%llu mean=%llu", (u64)sdist, ++ (u64)bfqq->seek_mean); ++} ++ ++/* ++ * Disable idle window if the process thinks too long or seeks so much that ++ * it doesn't matter. ++ */ ++static void bfq_update_idle_window(struct bfq_data *bfqd, ++ struct bfq_queue *bfqq, ++ struct bfq_io_cq *bic) ++{ ++ int enable_idle; ++ ++ /* Don't idle for async or idle io prio class. */ ++ if (!bfq_bfqq_sync(bfqq) || bfq_class_idle(bfqq)) ++ return; ++ ++ /* Idle window just restored, statistics are meaningless. */ ++ if (bfq_bfqq_just_split(bfqq)) ++ return; ++ ++ enable_idle = bfq_bfqq_idle_window(bfqq); ++ ++ if (atomic_read(&bic->icq.ioc->active_ref) == 0 || ++ bfqd->bfq_slice_idle == 0 || ++ (bfqd->hw_tag && BFQQ_SEEKY(bfqq) && ++ bfqq->raising_coeff == 1)) ++ enable_idle = 0; ++ else if (bfq_sample_valid(bic->ttime.ttime_samples)) { ++ if (bic->ttime.ttime_mean > bfqd->bfq_slice_idle && ++ bfqq->raising_coeff == 1) ++ enable_idle = 0; ++ else ++ enable_idle = 1; ++ } ++ bfq_log_bfqq(bfqd, bfqq, "update_idle_window: enable_idle %d", ++ enable_idle); ++ ++ if (enable_idle) ++ bfq_mark_bfqq_idle_window(bfqq); ++ else ++ bfq_clear_bfqq_idle_window(bfqq); ++} ++ ++/* ++ * Called when a new fs request (rq) is added to bfqq. Check if there's ++ * something we should do about it. ++ */ ++static void bfq_rq_enqueued(struct bfq_data *bfqd, struct bfq_queue *bfqq, ++ struct request *rq) ++{ ++ struct bfq_io_cq *bic = RQ_BIC(rq); ++ ++ if (rq->cmd_flags & REQ_META) ++ bfqq->meta_pending++; ++ ++ bfq_update_io_thinktime(bfqd, bic); ++ bfq_update_io_seektime(bfqd, bfqq, rq); ++ if (bfqq->entity.service > bfq_max_budget(bfqd) / 8 || ++ !BFQQ_SEEKY(bfqq)) ++ bfq_update_idle_window(bfqd, bfqq, bic); ++ bfq_clear_bfqq_just_split(bfqq); ++ ++ bfq_log_bfqq(bfqd, bfqq, ++ "rq_enqueued: idle_window=%d (seeky %d, mean %llu)", ++ bfq_bfqq_idle_window(bfqq), BFQQ_SEEKY(bfqq), ++ (long long unsigned)bfqq->seek_mean); ++ ++ bfqq->last_request_pos = blk_rq_pos(rq) + blk_rq_sectors(rq); ++ ++ if (bfqq == bfqd->active_queue) { ++ /* ++ * If there is just this request queued and the request ++ * is small, just exit. ++ * In this way, if the disk is being idled to wait for a new ++ * request from the active queue, we avoid unplugging the ++ * device now. ++ * ++ * By doing so, we spare the disk to be committed ++ * to serve just a small request. On the contrary, we wait for ++ * the block layer to decide when to unplug the device: ++ * hopefully, new requests will be merged to this ++ * one quickly, then the device will be unplugged ++ * and larger requests will be dispatched. ++ */ ++ if (bfqq->queued[rq_is_sync(rq)] == 1 && ++ blk_rq_sectors(rq) < 32) { ++ return; ++ } ++ if (bfq_bfqq_wait_request(bfqq)) { ++ /* ++ * If we are waiting for a request for this queue, let ++ * it rip immediately and flag that we must not expire ++ * this queue just now. ++ */ ++ bfq_clear_bfqq_wait_request(bfqq); ++ del_timer(&bfqd->idle_slice_timer); ++ /* ++ * Here we can safely expire the queue, in ++ * case of budget timeout, without wasting ++ * guarantees ++ */ ++ if (bfq_bfqq_budget_timeout(bfqq)) ++ bfq_bfqq_expire(bfqd, bfqq, 0, ++ BFQ_BFQQ_BUDGET_TIMEOUT); ++ __blk_run_queue(bfqd->queue); ++ } ++ } ++} ++ ++static void bfq_insert_request(struct request_queue *q, struct request *rq) ++{ ++ struct bfq_data *bfqd = q->elevator->elevator_data; ++ struct bfq_queue *bfqq = RQ_BFQQ(rq), *new_bfqq; ++ ++ assert_spin_locked(bfqd->queue->queue_lock); ++ ++ /* ++ * An unplug may trigger a requeue of a request from the device ++ * driver: make sure we are in process context while trying to ++ * merge two bfq_queues. ++ */ ++ if (!in_interrupt() && ++ (new_bfqq = bfq_setup_cooperator(bfqd, bfqq, rq, true))) { ++ if (bic_to_bfqq(RQ_BIC(rq), 1) != bfqq) ++ new_bfqq = bic_to_bfqq(RQ_BIC(rq), 1); ++ /* ++ * Release the request's reference to the old bfqq ++ * and make sure one is taken to the shared queue. ++ */ ++ new_bfqq->allocated[rq_data_dir(rq)]++; ++ bfqq->allocated[rq_data_dir(rq)]--; ++ atomic_inc(&new_bfqq->ref); ++ bfq_put_queue(bfqq); ++ if (bic_to_bfqq(RQ_BIC(rq), 1) == bfqq) ++ bfq_merge_bfqqs(bfqd, RQ_BIC(rq), bfqq, new_bfqq); ++ rq->elv.priv[1] = new_bfqq; ++ bfqq = new_bfqq; ++ } ++ ++ bfq_init_prio_data(bfqq, RQ_BIC(rq)); ++ ++ bfq_add_rq_rb(rq); ++ ++ rq_set_fifo_time(rq, jiffies + bfqd->bfq_fifo_expire[rq_is_sync(rq)]); ++ list_add_tail(&rq->queuelist, &bfqq->fifo); ++ ++ bfq_rq_enqueued(bfqd, bfqq, rq); ++} ++ ++static void bfq_update_hw_tag(struct bfq_data *bfqd) ++{ ++ bfqd->max_rq_in_driver = max(bfqd->max_rq_in_driver, ++ bfqd->rq_in_driver); ++ ++ if (bfqd->hw_tag == 1) ++ return; ++ ++ /* ++ * This sample is valid if the number of outstanding requests ++ * is large enough to allow a queueing behavior. Note that the ++ * sum is not exact, as it's not taking into account deactivated ++ * requests. ++ */ ++ if (bfqd->rq_in_driver + bfqd->queued < BFQ_HW_QUEUE_THRESHOLD) ++ return; ++ ++ if (bfqd->hw_tag_samples++ < BFQ_HW_QUEUE_SAMPLES) ++ return; ++ ++ bfqd->hw_tag = bfqd->max_rq_in_driver > BFQ_HW_QUEUE_THRESHOLD; ++ bfqd->max_rq_in_driver = 0; ++ bfqd->hw_tag_samples = 0; ++} ++ ++static void bfq_completed_request(struct request_queue *q, struct request *rq) ++{ ++ struct bfq_queue *bfqq = RQ_BFQQ(rq); ++ struct bfq_data *bfqd = bfqq->bfqd; ++ const int sync = rq_is_sync(rq); ++ ++ bfq_log_bfqq(bfqd, bfqq, "completed %u sects req (%d)", ++ blk_rq_sectors(rq), sync); ++ ++ bfq_update_hw_tag(bfqd); ++ ++ WARN_ON(!bfqd->rq_in_driver); ++ WARN_ON(!bfqq->dispatched); ++ bfqd->rq_in_driver--; ++ bfqq->dispatched--; ++ ++ if (bfq_bfqq_sync(bfqq)) ++ bfqd->sync_flight--; ++ ++ if (sync) ++ RQ_BIC(rq)->ttime.last_end_request = jiffies; ++ ++ /* ++ * If this is the active queue, check if it needs to be expired, ++ * or if we want to idle in case it has no pending requests. ++ */ ++ if (bfqd->active_queue == bfqq) { ++ if (bfq_bfqq_budget_new(bfqq)) ++ bfq_set_budget_timeout(bfqd); ++ ++ /* Idling is disabled also for cooperation issues: ++ * 1) there is a close cooperator for the queue, or ++ * 2) the queue is shared and some cooperator is likely ++ * to be idle (in this case, by not arming the idle timer, ++ * we try to slow down the queue, to prevent the zones ++ * of the disk accessed by the active cooperators to become ++ * too distant from the zone that will be accessed by the ++ * currently idle cooperators) ++ */ ++ if (bfq_may_expire_for_budg_timeout(bfqq)) ++ bfq_bfqq_expire(bfqd, bfqq, 0, BFQ_BFQQ_BUDGET_TIMEOUT); ++ else if (sync && ++ (bfqd->rq_in_driver == 0 || ++ bfqq->raising_coeff > 1) ++ && RB_EMPTY_ROOT(&bfqq->sort_list) ++ && !bfq_close_cooperator(bfqd, bfqq, bfqd->last_position) ++ && (!bfq_bfqq_coop(bfqq) || ++ !bfq_bfqq_some_coop_idle(bfqq))) ++ bfq_arm_slice_timer(bfqd); ++ } ++ ++ if (!bfqd->rq_in_driver) ++ bfq_schedule_dispatch(bfqd); ++} ++ ++static inline int __bfq_may_queue(struct bfq_queue *bfqq) ++{ ++ if (bfq_bfqq_wait_request(bfqq) && bfq_bfqq_must_alloc(bfqq)) { ++ bfq_clear_bfqq_must_alloc(bfqq); ++ return ELV_MQUEUE_MUST; ++ } ++ ++ return ELV_MQUEUE_MAY; ++} ++ ++static int bfq_may_queue(struct request_queue *q, int rw) ++{ ++ struct bfq_data *bfqd = q->elevator->elevator_data; ++ struct task_struct *tsk = current; ++ struct bfq_io_cq *bic; ++ struct bfq_queue *bfqq; ++ ++ /* ++ * Don't force setup of a queue from here, as a call to may_queue ++ * does not necessarily imply that a request actually will be queued. ++ * So just lookup a possibly existing queue, or return 'may queue' ++ * if that fails. ++ */ ++ bic = bfq_bic_lookup(bfqd, tsk->io_context); ++ if (bic == NULL) ++ return ELV_MQUEUE_MAY; ++ ++ bfqq = bic_to_bfqq(bic, rw_is_sync(rw)); ++ if (bfqq != NULL) { ++ bfq_init_prio_data(bfqq, bic); ++ ++ return __bfq_may_queue(bfqq); ++ } ++ ++ return ELV_MQUEUE_MAY; ++} ++ ++/* ++ * Queue lock held here. ++ */ ++static void bfq_put_request(struct request *rq) ++{ ++ struct bfq_queue *bfqq = RQ_BFQQ(rq); ++ ++ if (bfqq != NULL) { ++ const int rw = rq_data_dir(rq); ++ ++ BUG_ON(!bfqq->allocated[rw]); ++ bfqq->allocated[rw]--; ++ ++ rq->elv.priv[0] = NULL; ++ rq->elv.priv[1] = NULL; ++ ++ bfq_log_bfqq(bfqq->bfqd, bfqq, "put_request %p, %d", ++ bfqq, atomic_read(&bfqq->ref)); ++ bfq_put_queue(bfqq); ++ } ++} ++ ++/* ++ * Returns NULL if a new bfqq should be allocated, or the old bfqq if this ++ * was the last process referring to said bfqq. ++ */ ++static struct bfq_queue * ++bfq_split_bfqq(struct bfq_io_cq *bic, struct bfq_queue *bfqq) ++{ ++ bfq_log_bfqq(bfqq->bfqd, bfqq, "splitting queue"); ++ ++ put_io_context(bic->icq.ioc); ++ ++ if (bfqq_process_refs(bfqq) == 1) { ++ bfqq->pid = current->pid; ++ bfq_clear_bfqq_some_coop_idle(bfqq); ++ bfq_clear_bfqq_coop(bfqq); ++ bfq_clear_bfqq_split_coop(bfqq); ++ return bfqq; ++ } ++ ++ bic_set_bfqq(bic, NULL, 1); ++ ++ bfq_put_cooperator(bfqq); ++ ++ bfq_put_queue(bfqq); ++ return NULL; ++} ++ ++/* ++ * Allocate bfq data structures associated with this request. ++ */ ++static int bfq_set_request(struct request_queue *q, struct request *rq, ++ struct bio *bio, gfp_t gfp_mask) ++{ ++ struct bfq_data *bfqd = q->elevator->elevator_data; ++ struct bfq_io_cq *bic = icq_to_bic(rq->elv.icq); ++ const int rw = rq_data_dir(rq); ++ const int is_sync = rq_is_sync(rq); ++ struct bfq_queue *bfqq; ++ struct bfq_group *bfqg; ++ unsigned long flags; ++ bool split = false; ++ ++ might_sleep_if(gfp_mask & __GFP_WAIT); ++ ++ bfq_changed_ioprio(bic); ++ ++ spin_lock_irqsave(q->queue_lock, flags); ++ ++ if (bic == NULL) ++ goto queue_fail; ++ ++ bfqg = bfq_bic_update_cgroup(bic); ++ ++new_queue: ++ bfqq = bic_to_bfqq(bic, is_sync); ++ if (bfqq == NULL || bfqq == &bfqd->oom_bfqq) { ++ bfqq = bfq_get_queue(bfqd, bfqg, is_sync, bic, gfp_mask); ++ bic_set_bfqq(bic, bfqq, is_sync); ++ } else { ++ /* If the queue was seeky for too long, break it apart. */ ++ if (bfq_bfqq_coop(bfqq) && bfq_bfqq_split_coop(bfqq)) { ++ bfq_log_bfqq(bfqd, bfqq, "breaking apart bfqq"); ++ bfqq = bfq_split_bfqq(bic, bfqq); ++ split = true; ++ if (!bfqq) ++ goto new_queue; ++ } ++ } ++ ++ bfqq->allocated[rw]++; ++ atomic_inc(&bfqq->ref); ++ bfq_log_bfqq(bfqd, bfqq, "set_request: bfqq %p, %d", bfqq, ++ atomic_read(&bfqq->ref)); ++ ++ rq->elv.priv[0] = bic; ++ rq->elv.priv[1] = bfqq; ++ ++ /* ++ * If a bfq_queue has only one process reference, it is owned ++ * by only one bfq_io_cq: we can set the bic field of the ++ * bfq_queue to the address of that structure. Also, if the ++ * queue has just been split, mark a flag so that the ++ * information is available to the other scheduler hooks. ++ */ ++ if (bfqq_process_refs(bfqq) == 1) { ++ bfqq->bic = bic; ++ if (split) { ++ bfq_mark_bfqq_just_split(bfqq); ++ /* ++ * If the queue has just been split from a shared queue, ++ * restore the idle window and the possible weight ++ * raising period. ++ */ ++ bfq_bfqq_resume_state(bfqq, bic); ++ } ++ } ++ ++ spin_unlock_irqrestore(q->queue_lock, flags); ++ ++ return 0; ++ ++queue_fail: ++ bfq_schedule_dispatch(bfqd); ++ spin_unlock_irqrestore(q->queue_lock, flags); ++ ++ return 1; ++} ++ ++static void bfq_kick_queue(struct work_struct *work) ++{ ++ struct bfq_data *bfqd = ++ container_of(work, struct bfq_data, unplug_work); ++ struct request_queue *q = bfqd->queue; ++ ++ spin_lock_irq(q->queue_lock); ++ __blk_run_queue(q); ++ spin_unlock_irq(q->queue_lock); ++} ++ ++/* ++ * Handler of the expiration of the timer running if the active_queue ++ * is idling inside its time slice. ++ */ ++static void bfq_idle_slice_timer(unsigned long data) ++{ ++ struct bfq_data *bfqd = (struct bfq_data *)data; ++ struct bfq_queue *bfqq; ++ unsigned long flags; ++ enum bfqq_expiration reason; ++ ++ spin_lock_irqsave(bfqd->queue->queue_lock, flags); ++ ++ bfqq = bfqd->active_queue; ++ /* ++ * Theoretical race here: active_queue can be NULL or different ++ * from the queue that was idling if the timer handler spins on ++ * the queue_lock and a new request arrives for the current ++ * queue and there is a full dispatch cycle that changes the ++ * active_queue. This can hardly happen, but in the worst case ++ * we just expire a queue too early. ++ */ ++ if (bfqq != NULL) { ++ bfq_log_bfqq(bfqd, bfqq, "slice_timer expired"); ++ if (bfq_bfqq_budget_timeout(bfqq)) ++ /* ++ * Also here the queue can be safely expired ++ * for budget timeout without wasting ++ * guarantees ++ */ ++ reason = BFQ_BFQQ_BUDGET_TIMEOUT; ++ else if (bfqq->queued[0] == 0 && bfqq->queued[1] == 0) ++ /* ++ * The queue may not be empty upon timer expiration, ++ * because we may not disable the timer when the first ++ * request of the active queue arrives during ++ * disk idling ++ */ ++ reason = BFQ_BFQQ_TOO_IDLE; ++ else ++ goto schedule_dispatch; ++ ++ bfq_bfqq_expire(bfqd, bfqq, 1, reason); ++ } ++ ++schedule_dispatch: ++ bfq_schedule_dispatch(bfqd); ++ ++ spin_unlock_irqrestore(bfqd->queue->queue_lock, flags); ++} ++ ++static void bfq_shutdown_timer_wq(struct bfq_data *bfqd) ++{ ++ del_timer_sync(&bfqd->idle_slice_timer); ++ cancel_work_sync(&bfqd->unplug_work); ++} ++ ++static inline void __bfq_put_async_bfqq(struct bfq_data *bfqd, ++ struct bfq_queue **bfqq_ptr) ++{ ++ struct bfq_group *root_group = bfqd->root_group; ++ struct bfq_queue *bfqq = *bfqq_ptr; ++ ++ bfq_log(bfqd, "put_async_bfqq: %p", bfqq); ++ if (bfqq != NULL) { ++ bfq_bfqq_move(bfqd, bfqq, &bfqq->entity, root_group); ++ bfq_log_bfqq(bfqd, bfqq, "put_async_bfqq: putting %p, %d", ++ bfqq, atomic_read(&bfqq->ref)); ++ bfq_put_queue(bfqq); ++ *bfqq_ptr = NULL; ++ } ++} ++ ++/* ++ * Release all the bfqg references to its async queues. If we are ++ * deallocating the group these queues may still contain requests, so ++ * we reparent them to the root cgroup (i.e., the only one that will ++ * exist for sure untill all the requests on a device are gone). ++ */ ++static void bfq_put_async_queues(struct bfq_data *bfqd, struct bfq_group *bfqg) ++{ ++ int i, j; ++ ++ for (i = 0; i < 2; i++) ++ for (j = 0; j < IOPRIO_BE_NR; j++) ++ __bfq_put_async_bfqq(bfqd, &bfqg->async_bfqq[i][j]); ++ ++ __bfq_put_async_bfqq(bfqd, &bfqg->async_idle_bfqq); ++} ++ ++static void bfq_exit_queue(struct elevator_queue *e) ++{ ++ struct bfq_data *bfqd = e->elevator_data; ++ struct request_queue *q = bfqd->queue; ++ struct bfq_queue *bfqq, *n; ++ ++ bfq_shutdown_timer_wq(bfqd); ++ ++ spin_lock_irq(q->queue_lock); ++ ++ BUG_ON(bfqd->active_queue != NULL); ++ list_for_each_entry_safe(bfqq, n, &bfqd->idle_list, bfqq_list) ++ bfq_deactivate_bfqq(bfqd, bfqq, 0); ++ ++ bfq_disconnect_groups(bfqd); ++ spin_unlock_irq(q->queue_lock); ++ ++ bfq_shutdown_timer_wq(bfqd); ++ ++ synchronize_rcu(); ++ ++ BUG_ON(timer_pending(&bfqd->idle_slice_timer)); ++ ++ bfq_free_root_group(bfqd); ++ kfree(bfqd); ++} ++ ++static int bfq_init_queue(struct request_queue *q) ++{ ++ struct bfq_group *bfqg; ++ struct bfq_data *bfqd; ++ ++ bfqd = kmalloc_node(sizeof(*bfqd), GFP_KERNEL | __GFP_ZERO, q->node); ++ if (bfqd == NULL) ++ return -ENOMEM; ++ ++ /* ++ * Our fallback bfqq if bfq_find_alloc_queue() runs into OOM issues. ++ * Grab a permanent reference to it, so that the normal code flow ++ * will not attempt to free it. ++ */ ++ bfq_init_bfqq(bfqd, &bfqd->oom_bfqq, 1, 0); ++ atomic_inc(&bfqd->oom_bfqq.ref); ++ ++ bfqd->queue = q; ++ q->elevator->elevator_data = bfqd; ++ ++ bfqg = bfq_alloc_root_group(bfqd, q->node); ++ if (bfqg == NULL) { ++ kfree(bfqd); ++ return -ENOMEM; ++ } ++ ++ bfqd->root_group = bfqg; ++ ++ init_timer(&bfqd->idle_slice_timer); ++ bfqd->idle_slice_timer.function = bfq_idle_slice_timer; ++ bfqd->idle_slice_timer.data = (unsigned long)bfqd; ++ ++ bfqd->rq_pos_tree = RB_ROOT; ++ ++ INIT_WORK(&bfqd->unplug_work, bfq_kick_queue); ++ ++ INIT_LIST_HEAD(&bfqd->active_list); ++ INIT_LIST_HEAD(&bfqd->idle_list); ++ ++ bfqd->hw_tag = -1; ++ ++ bfqd->bfq_max_budget = bfq_default_max_budget; ++ ++ bfqd->bfq_quantum = bfq_quantum; ++ bfqd->bfq_fifo_expire[0] = bfq_fifo_expire[0]; ++ bfqd->bfq_fifo_expire[1] = bfq_fifo_expire[1]; ++ bfqd->bfq_back_max = bfq_back_max; ++ bfqd->bfq_back_penalty = bfq_back_penalty; ++ bfqd->bfq_slice_idle = bfq_slice_idle; ++ bfqd->bfq_class_idle_last_service = 0; ++ bfqd->bfq_max_budget_async_rq = bfq_max_budget_async_rq; ++ bfqd->bfq_timeout[BLK_RW_ASYNC] = bfq_timeout_async; ++ bfqd->bfq_timeout[BLK_RW_SYNC] = bfq_timeout_sync; ++ ++ bfqd->low_latency = true; ++ ++ bfqd->bfq_raising_coeff = 20; ++ bfqd->bfq_raising_rt_max_time = msecs_to_jiffies(300); ++ bfqd->bfq_raising_max_time = 0; ++ bfqd->bfq_raising_min_idle_time = msecs_to_jiffies(2000); ++ bfqd->bfq_raising_min_inter_arr_async = msecs_to_jiffies(500); ++ bfqd->bfq_raising_max_softrt_rate = 7000; ++ ++ /* Initially estimate the device's peak rate as the reference rate */ ++ if (blk_queue_nonrot(bfqd->queue)) { ++ bfqd->RT_prod = R_nonrot * T_nonrot; ++ bfqd->peak_rate = R_nonrot; ++ } else { ++ bfqd->RT_prod = R_rot * T_rot; ++ bfqd->peak_rate = R_rot; ++ } ++ ++ return 0; ++} ++ ++static void bfq_slab_kill(void) ++{ ++ if (bfq_pool != NULL) ++ kmem_cache_destroy(bfq_pool); ++} ++ ++static int __init bfq_slab_setup(void) ++{ ++ bfq_pool = KMEM_CACHE(bfq_queue, 0); ++ if (bfq_pool == NULL) ++ return -ENOMEM; ++ return 0; ++} ++ ++static ssize_t bfq_var_show(unsigned int var, char *page) ++{ ++ return sprintf(page, "%d\n", var); ++} ++ ++static ssize_t bfq_var_store(unsigned long *var, const char *page, size_t count) ++{ ++ unsigned long new_val; ++ int ret = strict_strtoul(page, 10, &new_val); ++ ++ if (ret == 0) ++ *var = new_val; ++ ++ return count; ++} ++ ++static ssize_t bfq_raising_max_time_show(struct elevator_queue *e, char *page) ++{ ++ struct bfq_data *bfqd = e->elevator_data; ++ return sprintf(page, "%d\n", bfqd->bfq_raising_max_time > 0 ? ++ bfqd->bfq_raising_max_time : ++ bfq_wrais_duration(bfqd)); ++} ++ ++static ssize_t bfq_weights_show(struct elevator_queue *e, char *page) ++{ ++ struct bfq_queue *bfqq; ++ struct bfq_data *bfqd = e->elevator_data; ++ ssize_t num_char = 0; ++ ++ num_char += sprintf(page + num_char, "Tot reqs queued %d\n\n", ++ bfqd->queued); ++ ++ spin_lock_irq(bfqd->queue->queue_lock); ++ ++ num_char += sprintf(page + num_char, "Active:\n"); ++ list_for_each_entry(bfqq, &bfqd->active_list, bfqq_list) { ++ num_char += sprintf(page + num_char, ++ "pid%d: weight %hu, nr_queued %d %d," ++ " dur %d/%u\n", ++ bfqq->pid, ++ bfqq->entity.weight, ++ bfqq->queued[0], ++ bfqq->queued[1], ++ jiffies_to_msecs(jiffies - ++ bfqq->last_rais_start_finish), ++ jiffies_to_msecs(bfqq->raising_cur_max_time)); ++ } ++ ++ num_char += sprintf(page + num_char, "Idle:\n"); ++ list_for_each_entry(bfqq, &bfqd->idle_list, bfqq_list) { ++ num_char += sprintf(page + num_char, ++ "pid%d: weight %hu, dur %d/%u\n", ++ bfqq->pid, ++ bfqq->entity.weight, ++ jiffies_to_msecs(jiffies - ++ bfqq->last_rais_start_finish), ++ jiffies_to_msecs(bfqq->raising_cur_max_time)); ++ } ++ ++ spin_unlock_irq(bfqd->queue->queue_lock); ++ ++ return num_char; ++} ++ ++#define SHOW_FUNCTION(__FUNC, __VAR, __CONV) \ ++static ssize_t __FUNC(struct elevator_queue *e, char *page) \ ++{ \ ++ struct bfq_data *bfqd = e->elevator_data; \ ++ unsigned int __data = __VAR; \ ++ if (__CONV) \ ++ __data = jiffies_to_msecs(__data); \ ++ return bfq_var_show(__data, (page)); \ ++} ++SHOW_FUNCTION(bfq_quantum_show, bfqd->bfq_quantum, 0); ++SHOW_FUNCTION(bfq_fifo_expire_sync_show, bfqd->bfq_fifo_expire[1], 1); ++SHOW_FUNCTION(bfq_fifo_expire_async_show, bfqd->bfq_fifo_expire[0], 1); ++SHOW_FUNCTION(bfq_back_seek_max_show, bfqd->bfq_back_max, 0); ++SHOW_FUNCTION(bfq_back_seek_penalty_show, bfqd->bfq_back_penalty, 0); ++SHOW_FUNCTION(bfq_slice_idle_show, bfqd->bfq_slice_idle, 1); ++SHOW_FUNCTION(bfq_max_budget_show, bfqd->bfq_user_max_budget, 0); ++SHOW_FUNCTION(bfq_max_budget_async_rq_show, bfqd->bfq_max_budget_async_rq, 0); ++SHOW_FUNCTION(bfq_timeout_sync_show, bfqd->bfq_timeout[BLK_RW_SYNC], 1); ++SHOW_FUNCTION(bfq_timeout_async_show, bfqd->bfq_timeout[BLK_RW_ASYNC], 1); ++SHOW_FUNCTION(bfq_low_latency_show, bfqd->low_latency, 0); ++SHOW_FUNCTION(bfq_raising_coeff_show, bfqd->bfq_raising_coeff, 0); ++SHOW_FUNCTION(bfq_raising_rt_max_time_show, bfqd->bfq_raising_rt_max_time, 1); ++SHOW_FUNCTION(bfq_raising_min_idle_time_show, bfqd->bfq_raising_min_idle_time, ++ 1); ++SHOW_FUNCTION(bfq_raising_min_inter_arr_async_show, ++ bfqd->bfq_raising_min_inter_arr_async, ++ 1); ++SHOW_FUNCTION(bfq_raising_max_softrt_rate_show, ++ bfqd->bfq_raising_max_softrt_rate, 0); ++#undef SHOW_FUNCTION ++ ++#define STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, __CONV) \ ++static ssize_t \ ++__FUNC(struct elevator_queue *e, const char *page, size_t count) \ ++{ \ ++ struct bfq_data *bfqd = e->elevator_data; \ ++ unsigned long __data; \ ++ int ret = bfq_var_store(&__data, (page), count); \ ++ if (__data < (MIN)) \ ++ __data = (MIN); \ ++ else if (__data > (MAX)) \ ++ __data = (MAX); \ ++ if (__CONV) \ ++ *(__PTR) = msecs_to_jiffies(__data); \ ++ else \ ++ *(__PTR) = __data; \ ++ return ret; \ ++} ++STORE_FUNCTION(bfq_quantum_store, &bfqd->bfq_quantum, 1, INT_MAX, 0); ++STORE_FUNCTION(bfq_fifo_expire_sync_store, &bfqd->bfq_fifo_expire[1], 1, ++ INT_MAX, 1); ++STORE_FUNCTION(bfq_fifo_expire_async_store, &bfqd->bfq_fifo_expire[0], 1, ++ INT_MAX, 1); ++STORE_FUNCTION(bfq_back_seek_max_store, &bfqd->bfq_back_max, 0, INT_MAX, 0); ++STORE_FUNCTION(bfq_back_seek_penalty_store, &bfqd->bfq_back_penalty, 1, ++ INT_MAX, 0); ++STORE_FUNCTION(bfq_slice_idle_store, &bfqd->bfq_slice_idle, 0, INT_MAX, 1); ++STORE_FUNCTION(bfq_max_budget_async_rq_store, &bfqd->bfq_max_budget_async_rq, ++ 1, INT_MAX, 0); ++STORE_FUNCTION(bfq_timeout_async_store, &bfqd->bfq_timeout[BLK_RW_ASYNC], 0, ++ INT_MAX, 1); ++STORE_FUNCTION(bfq_raising_coeff_store, &bfqd->bfq_raising_coeff, 1, ++ INT_MAX, 0); ++STORE_FUNCTION(bfq_raising_max_time_store, &bfqd->bfq_raising_max_time, 0, ++ INT_MAX, 1); ++STORE_FUNCTION(bfq_raising_rt_max_time_store, &bfqd->bfq_raising_rt_max_time, 0, ++ INT_MAX, 1); ++STORE_FUNCTION(bfq_raising_min_idle_time_store, ++ &bfqd->bfq_raising_min_idle_time, 0, INT_MAX, 1); ++STORE_FUNCTION(bfq_raising_min_inter_arr_async_store, ++ &bfqd->bfq_raising_min_inter_arr_async, 0, INT_MAX, 1); ++STORE_FUNCTION(bfq_raising_max_softrt_rate_store, ++ &bfqd->bfq_raising_max_softrt_rate, 0, INT_MAX, 0); ++#undef STORE_FUNCTION ++ ++/* do nothing for the moment */ ++static ssize_t bfq_weights_store(struct elevator_queue *e, ++ const char *page, size_t count) ++{ ++ return count; ++} ++ ++static inline unsigned long bfq_estimated_max_budget(struct bfq_data *bfqd) ++{ ++ u64 timeout = jiffies_to_msecs(bfqd->bfq_timeout[BLK_RW_SYNC]); ++ ++ if (bfqd->peak_rate_samples >= BFQ_PEAK_RATE_SAMPLES) ++ return bfq_calc_max_budget(bfqd->peak_rate, timeout); ++ else ++ return bfq_default_max_budget; ++} ++ ++static ssize_t bfq_max_budget_store(struct elevator_queue *e, ++ const char *page, size_t count) ++{ ++ struct bfq_data *bfqd = e->elevator_data; ++ unsigned long __data; ++ int ret = bfq_var_store(&__data, (page), count); ++ ++ if (__data == 0) ++ bfqd->bfq_max_budget = bfq_estimated_max_budget(bfqd); ++ else { ++ if (__data > INT_MAX) ++ __data = INT_MAX; ++ bfqd->bfq_max_budget = __data; ++ } ++ ++ bfqd->bfq_user_max_budget = __data; ++ ++ return ret; ++} ++ ++static ssize_t bfq_timeout_sync_store(struct elevator_queue *e, ++ const char *page, size_t count) ++{ ++ struct bfq_data *bfqd = e->elevator_data; ++ unsigned long __data; ++ int ret = bfq_var_store(&__data, (page), count); ++ ++ if (__data < 1) ++ __data = 1; ++ else if (__data > INT_MAX) ++ __data = INT_MAX; ++ ++ bfqd->bfq_timeout[BLK_RW_SYNC] = msecs_to_jiffies(__data); ++ if (bfqd->bfq_user_max_budget == 0) ++ bfqd->bfq_max_budget = bfq_estimated_max_budget(bfqd); ++ ++ return ret; ++} ++ ++static ssize_t bfq_low_latency_store(struct elevator_queue *e, ++ const char *page, size_t count) ++{ ++ struct bfq_data *bfqd = e->elevator_data; ++ unsigned long __data; ++ int ret = bfq_var_store(&__data, (page), count); ++ ++ if (__data > 1) ++ __data = 1; ++ bfqd->low_latency = __data; ++ ++ return ret; ++} ++ ++#define BFQ_ATTR(name) \ ++ __ATTR(name, S_IRUGO|S_IWUSR, bfq_##name##_show, bfq_##name##_store) ++ ++static struct elv_fs_entry bfq_attrs[] = { ++ BFQ_ATTR(quantum), ++ BFQ_ATTR(fifo_expire_sync), ++ BFQ_ATTR(fifo_expire_async), ++ BFQ_ATTR(back_seek_max), ++ BFQ_ATTR(back_seek_penalty), ++ BFQ_ATTR(slice_idle), ++ BFQ_ATTR(max_budget), ++ BFQ_ATTR(max_budget_async_rq), ++ BFQ_ATTR(timeout_sync), ++ BFQ_ATTR(timeout_async), ++ BFQ_ATTR(low_latency), ++ BFQ_ATTR(raising_coeff), ++ BFQ_ATTR(raising_max_time), ++ BFQ_ATTR(raising_rt_max_time), ++ BFQ_ATTR(raising_min_idle_time), ++ BFQ_ATTR(raising_min_inter_arr_async), ++ BFQ_ATTR(raising_max_softrt_rate), ++ BFQ_ATTR(weights), ++ __ATTR_NULL ++}; ++ ++static struct elevator_type iosched_bfq = { ++ .ops = { ++ .elevator_merge_fn = bfq_merge, ++ .elevator_merged_fn = bfq_merged_request, ++ .elevator_merge_req_fn = bfq_merged_requests, ++ .elevator_allow_merge_fn = bfq_allow_merge, ++ .elevator_dispatch_fn = bfq_dispatch_requests, ++ .elevator_add_req_fn = bfq_insert_request, ++ .elevator_activate_req_fn = bfq_activate_request, ++ .elevator_deactivate_req_fn = bfq_deactivate_request, ++ .elevator_completed_req_fn = bfq_completed_request, ++ .elevator_former_req_fn = elv_rb_former_request, ++ .elevator_latter_req_fn = elv_rb_latter_request, ++ .elevator_init_icq_fn = bfq_init_icq, ++ .elevator_exit_icq_fn = bfq_exit_icq, ++ .elevator_set_req_fn = bfq_set_request, ++ .elevator_put_req_fn = bfq_put_request, ++ .elevator_may_queue_fn = bfq_may_queue, ++ .elevator_init_fn = bfq_init_queue, ++ .elevator_exit_fn = bfq_exit_queue, ++ }, ++ .icq_size = sizeof(struct bfq_io_cq), ++ .icq_align = __alignof__(struct bfq_io_cq), ++ .elevator_attrs = bfq_attrs, ++ .elevator_name = "bfq", ++ .elevator_owner = THIS_MODULE, ++}; ++ ++static int __init bfq_init(void) ++{ ++ /* ++ * Can be 0 on HZ < 1000 setups. ++ */ ++ if (bfq_slice_idle == 0) ++ bfq_slice_idle = 1; ++ ++ if (bfq_timeout_async == 0) ++ bfq_timeout_async = 1; ++ ++ if (bfq_slab_setup()) ++ return -ENOMEM; ++ ++ elv_register(&iosched_bfq); ++ ++ return 0; ++} ++ ++static void __exit bfq_exit(void) ++{ ++ elv_unregister(&iosched_bfq); ++ bfq_slab_kill(); ++} ++ ++module_init(bfq_init); ++module_exit(bfq_exit); ++ ++MODULE_AUTHOR("Fabio Checconi, Paolo Valente"); ++MODULE_LICENSE("GPL"); ++MODULE_DESCRIPTION("Budget Fair Queueing IO scheduler"); +diff --git a/block/bfq-sched.c b/block/bfq-sched.c +new file mode 100644 +index 0000000..a0edaa2 +--- /dev/null ++++ b/block/bfq-sched.c +@@ -0,0 +1,1044 @@ ++/* ++ * BFQ: Hierarchical B-WF2Q+ scheduler. ++ * ++ * Based on ideas and code from CFQ: ++ * Copyright (C) 2003 Jens Axboe ++ * ++ * Copyright (C) 2008 Fabio Checconi ++ * Paolo Valente ++ * ++ * Copyright (C) 2010 Paolo Valente ++ */ ++ ++#ifdef CONFIG_CGROUP_BFQIO ++#define for_each_entity(entity) \ ++ for (; entity != NULL; entity = entity->parent) ++ ++#define for_each_entity_safe(entity, parent) \ ++ for (; entity && ({ parent = entity->parent; 1; }); entity = parent) ++ ++static struct bfq_entity *bfq_lookup_next_entity(struct bfq_sched_data *sd, ++ int extract, ++ struct bfq_data *bfqd); ++ ++static inline void bfq_update_budget(struct bfq_entity *next_active) ++{ ++ struct bfq_entity *bfqg_entity; ++ struct bfq_group *bfqg; ++ struct bfq_sched_data *group_sd; ++ ++ BUG_ON(next_active == NULL); ++ ++ group_sd = next_active->sched_data; ++ ++ bfqg = container_of(group_sd, struct bfq_group, sched_data); ++ /* ++ * bfq_group's my_entity field is not NULL only if the group ++ * is not the root group. We must not touch the root entity ++ * as it must never become an active entity. ++ */ ++ bfqg_entity = bfqg->my_entity; ++ if (bfqg_entity != NULL) ++ bfqg_entity->budget = next_active->budget; ++} ++ ++static int bfq_update_next_active(struct bfq_sched_data *sd) ++{ ++ struct bfq_entity *next_active; ++ ++ if (sd->active_entity != NULL) ++ /* will update/requeue at the end of service */ ++ return 0; ++ ++ /* ++ * NOTE: this can be improved in many ways, such as returning ++ * 1 (and thus propagating upwards the update) only when the ++ * budget changes, or caching the bfqq that will be scheduled ++ * next from this subtree. By now we worry more about ++ * correctness than about performance... ++ */ ++ next_active = bfq_lookup_next_entity(sd, 0, NULL); ++ sd->next_active = next_active; ++ ++ if (next_active != NULL) ++ bfq_update_budget(next_active); ++ ++ return 1; ++} ++ ++static inline void bfq_check_next_active(struct bfq_sched_data *sd, ++ struct bfq_entity *entity) ++{ ++ BUG_ON(sd->next_active != entity); ++} ++#else ++#define for_each_entity(entity) \ ++ for (; entity != NULL; entity = NULL) ++ ++#define for_each_entity_safe(entity, parent) \ ++ for (parent = NULL; entity != NULL; entity = parent) ++ ++static inline int bfq_update_next_active(struct bfq_sched_data *sd) ++{ ++ return 0; ++} ++ ++static inline void bfq_check_next_active(struct bfq_sched_data *sd, ++ struct bfq_entity *entity) ++{ ++} ++ ++static inline void bfq_update_budget(struct bfq_entity *next_active) ++{ ++} ++#endif ++ ++/* ++ * Shift for timestamp calculations. This actually limits the maximum ++ * service allowed in one timestamp delta (small shift values increase it), ++ * the maximum total weight that can be used for the queues in the system ++ * (big shift values increase it), and the period of virtual time wraparounds. ++ */ ++#define WFQ_SERVICE_SHIFT 22 ++ ++/** ++ * bfq_gt - compare two timestamps. ++ * @a: first ts. ++ * @b: second ts. ++ * ++ * Return @a > @b, dealing with wrapping correctly. ++ */ ++static inline int bfq_gt(u64 a, u64 b) ++{ ++ return (s64)(a - b) > 0; ++} ++ ++static inline struct bfq_queue *bfq_entity_to_bfqq(struct bfq_entity *entity) ++{ ++ struct bfq_queue *bfqq = NULL; ++ ++ BUG_ON(entity == NULL); ++ ++ if (entity->my_sched_data == NULL) ++ bfqq = container_of(entity, struct bfq_queue, entity); ++ ++ return bfqq; ++} ++ ++ ++/** ++ * bfq_delta - map service into the virtual time domain. ++ * @service: amount of service. ++ * @weight: scale factor (weight of an entity or weight sum). ++ */ ++static inline u64 bfq_delta(unsigned long service, ++ unsigned long weight) ++{ ++ u64 d = (u64)service << WFQ_SERVICE_SHIFT; ++ ++ do_div(d, weight); ++ return d; ++} ++ ++/** ++ * bfq_calc_finish - assign the finish time to an entity. ++ * @entity: the entity to act upon. ++ * @service: the service to be charged to the entity. ++ */ ++static inline void bfq_calc_finish(struct bfq_entity *entity, ++ unsigned long service) ++{ ++ struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity); ++ ++ BUG_ON(entity->weight == 0); ++ ++ entity->finish = entity->start + ++ bfq_delta(service, entity->weight); ++ ++ if (bfqq != NULL) { ++ bfq_log_bfqq(bfqq->bfqd, bfqq, ++ "calc_finish: serv %lu, w %d", ++ service, entity->weight); ++ bfq_log_bfqq(bfqq->bfqd, bfqq, ++ "calc_finish: start %llu, finish %llu, delta %llu", ++ entity->start, entity->finish, ++ bfq_delta(service, entity->weight)); ++ } ++} ++ ++/** ++ * bfq_entity_of - get an entity from a node. ++ * @node: the node field of the entity. ++ * ++ * Convert a node pointer to the relative entity. This is used only ++ * to simplify the logic of some functions and not as the generic ++ * conversion mechanism because, e.g., in the tree walking functions, ++ * the check for a %NULL value would be redundant. ++ */ ++static inline struct bfq_entity *bfq_entity_of(struct rb_node *node) ++{ ++ struct bfq_entity *entity = NULL; ++ ++ if (node != NULL) ++ entity = rb_entry(node, struct bfq_entity, rb_node); ++ ++ return entity; ++} ++ ++/** ++ * bfq_extract - remove an entity from a tree. ++ * @root: the tree root. ++ * @entity: the entity to remove. ++ */ ++static inline void bfq_extract(struct rb_root *root, ++ struct bfq_entity *entity) ++{ ++ BUG_ON(entity->tree != root); ++ ++ entity->tree = NULL; ++ rb_erase(&entity->rb_node, root); ++} ++ ++/** ++ * bfq_idle_extract - extract an entity from the idle tree. ++ * @st: the service tree of the owning @entity. ++ * @entity: the entity being removed. ++ */ ++static void bfq_idle_extract(struct bfq_service_tree *st, ++ struct bfq_entity *entity) ++{ ++ struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity); ++ struct rb_node *next; ++ ++ BUG_ON(entity->tree != &st->idle); ++ ++ if (entity == st->first_idle) { ++ next = rb_next(&entity->rb_node); ++ st->first_idle = bfq_entity_of(next); ++ } ++ ++ if (entity == st->last_idle) { ++ next = rb_prev(&entity->rb_node); ++ st->last_idle = bfq_entity_of(next); ++ } ++ ++ bfq_extract(&st->idle, entity); ++ ++ if (bfqq != NULL) ++ list_del(&bfqq->bfqq_list); ++} ++ ++/** ++ * bfq_insert - generic tree insertion. ++ * @root: tree root. ++ * @entity: entity to insert. ++ * ++ * This is used for the idle and the active tree, since they are both ++ * ordered by finish time. ++ */ ++static void bfq_insert(struct rb_root *root, struct bfq_entity *entity) ++{ ++ struct bfq_entity *entry; ++ struct rb_node **node = &root->rb_node; ++ struct rb_node *parent = NULL; ++ ++ BUG_ON(entity->tree != NULL); ++ ++ while (*node != NULL) { ++ parent = *node; ++ entry = rb_entry(parent, struct bfq_entity, rb_node); ++ ++ if (bfq_gt(entry->finish, entity->finish)) ++ node = &parent->rb_left; ++ else ++ node = &parent->rb_right; ++ } ++ ++ rb_link_node(&entity->rb_node, parent, node); ++ rb_insert_color(&entity->rb_node, root); ++ ++ entity->tree = root; ++} ++ ++/** ++ * bfq_update_min - update the min_start field of a entity. ++ * @entity: the entity to update. ++ * @node: one of its children. ++ * ++ * This function is called when @entity may store an invalid value for ++ * min_start due to updates to the active tree. The function assumes ++ * that the subtree rooted at @node (which may be its left or its right ++ * child) has a valid min_start value. ++ */ ++static inline void bfq_update_min(struct bfq_entity *entity, ++ struct rb_node *node) ++{ ++ struct bfq_entity *child; ++ ++ if (node != NULL) { ++ child = rb_entry(node, struct bfq_entity, rb_node); ++ if (bfq_gt(entity->min_start, child->min_start)) ++ entity->min_start = child->min_start; ++ } ++} ++ ++/** ++ * bfq_update_active_node - recalculate min_start. ++ * @node: the node to update. ++ * ++ * @node may have changed position or one of its children may have moved, ++ * this function updates its min_start value. The left and right subtrees ++ * are assumed to hold a correct min_start value. ++ */ ++static inline void bfq_update_active_node(struct rb_node *node) ++{ ++ struct bfq_entity *entity = rb_entry(node, struct bfq_entity, rb_node); ++ ++ entity->min_start = entity->start; ++ bfq_update_min(entity, node->rb_right); ++ bfq_update_min(entity, node->rb_left); ++} ++ ++/** ++ * bfq_update_active_tree - update min_start for the whole active tree. ++ * @node: the starting node. ++ * ++ * @node must be the deepest modified node after an update. This function ++ * updates its min_start using the values held by its children, assuming ++ * that they did not change, and then updates all the nodes that may have ++ * changed in the path to the root. The only nodes that may have changed ++ * are the ones in the path or their siblings. ++ */ ++static void bfq_update_active_tree(struct rb_node *node) ++{ ++ struct rb_node *parent; ++ ++up: ++ bfq_update_active_node(node); ++ ++ parent = rb_parent(node); ++ if (parent == NULL) ++ return; ++ ++ if (node == parent->rb_left && parent->rb_right != NULL) ++ bfq_update_active_node(parent->rb_right); ++ else if (parent->rb_left != NULL) ++ bfq_update_active_node(parent->rb_left); ++ ++ node = parent; ++ goto up; ++} ++ ++/** ++ * bfq_active_insert - insert an entity in the active tree of its group/device. ++ * @st: the service tree of the entity. ++ * @entity: the entity being inserted. ++ * ++ * The active tree is ordered by finish time, but an extra key is kept ++ * per each node, containing the minimum value for the start times of ++ * its children (and the node itself), so it's possible to search for ++ * the eligible node with the lowest finish time in logarithmic time. ++ */ ++static void bfq_active_insert(struct bfq_service_tree *st, ++ struct bfq_entity *entity) ++{ ++ struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity); ++ struct rb_node *node = &entity->rb_node; ++ ++ bfq_insert(&st->active, entity); ++ ++ if (node->rb_left != NULL) ++ node = node->rb_left; ++ else if (node->rb_right != NULL) ++ node = node->rb_right; ++ ++ bfq_update_active_tree(node); ++ ++ if (bfqq != NULL) ++ list_add(&bfqq->bfqq_list, &bfqq->bfqd->active_list); ++} ++ ++/** ++ * bfq_ioprio_to_weight - calc a weight from an ioprio. ++ * @ioprio: the ioprio value to convert. ++ */ ++static unsigned short bfq_ioprio_to_weight(int ioprio) ++{ ++ WARN_ON(ioprio < 0 || ioprio >= IOPRIO_BE_NR); ++ return IOPRIO_BE_NR - ioprio; ++} ++ ++/** ++ * bfq_weight_to_ioprio - calc an ioprio from a weight. ++ * @weight: the weight value to convert. ++ * ++ * To preserve as mush as possible the old only-ioprio user interface, ++ * 0 is used as an escape ioprio value for weights (numerically) equal or ++ * larger than IOPRIO_BE_NR ++ */ ++static unsigned short bfq_weight_to_ioprio(int weight) ++{ ++ WARN_ON(weight < BFQ_MIN_WEIGHT || weight > BFQ_MAX_WEIGHT); ++ return IOPRIO_BE_NR - weight < 0 ? 0 : IOPRIO_BE_NR - weight; ++} ++ ++static inline void bfq_get_entity(struct bfq_entity *entity) ++{ ++ struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity); ++ struct bfq_sched_data *sd; ++ ++ if (bfqq != NULL) { ++ sd = entity->sched_data; ++ atomic_inc(&bfqq->ref); ++ bfq_log_bfqq(bfqq->bfqd, bfqq, "get_entity: %p %d", ++ bfqq, atomic_read(&bfqq->ref)); ++ } ++} ++ ++/** ++ * bfq_find_deepest - find the deepest node that an extraction can modify. ++ * @node: the node being removed. ++ * ++ * Do the first step of an extraction in an rb tree, looking for the ++ * node that will replace @node, and returning the deepest node that ++ * the following modifications to the tree can touch. If @node is the ++ * last node in the tree return %NULL. ++ */ ++static struct rb_node *bfq_find_deepest(struct rb_node *node) ++{ ++ struct rb_node *deepest; ++ ++ if (node->rb_right == NULL && node->rb_left == NULL) ++ deepest = rb_parent(node); ++ else if (node->rb_right == NULL) ++ deepest = node->rb_left; ++ else if (node->rb_left == NULL) ++ deepest = node->rb_right; ++ else { ++ deepest = rb_next(node); ++ if (deepest->rb_right != NULL) ++ deepest = deepest->rb_right; ++ else if (rb_parent(deepest) != node) ++ deepest = rb_parent(deepest); ++ } ++ ++ return deepest; ++} ++ ++/** ++ * bfq_active_extract - remove an entity from the active tree. ++ * @st: the service_tree containing the tree. ++ * @entity: the entity being removed. ++ */ ++static void bfq_active_extract(struct bfq_service_tree *st, ++ struct bfq_entity *entity) ++{ ++ struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity); ++ struct rb_node *node; ++ ++ node = bfq_find_deepest(&entity->rb_node); ++ bfq_extract(&st->active, entity); ++ ++ if (node != NULL) ++ bfq_update_active_tree(node); ++ ++ if (bfqq != NULL) ++ list_del(&bfqq->bfqq_list); ++} ++ ++/** ++ * bfq_idle_insert - insert an entity into the idle tree. ++ * @st: the service tree containing the tree. ++ * @entity: the entity to insert. ++ */ ++static void bfq_idle_insert(struct bfq_service_tree *st, ++ struct bfq_entity *entity) ++{ ++ struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity); ++ struct bfq_entity *first_idle = st->first_idle; ++ struct bfq_entity *last_idle = st->last_idle; ++ ++ if (first_idle == NULL || bfq_gt(first_idle->finish, entity->finish)) ++ st->first_idle = entity; ++ if (last_idle == NULL || bfq_gt(entity->finish, last_idle->finish)) ++ st->last_idle = entity; ++ ++ bfq_insert(&st->idle, entity); ++ ++ if (bfqq != NULL) ++ list_add(&bfqq->bfqq_list, &bfqq->bfqd->idle_list); ++} ++ ++/** ++ * bfq_forget_entity - remove an entity from the wfq trees. ++ * @st: the service tree. ++ * @entity: the entity being removed. ++ * ++ * Update the device status and forget everything about @entity, putting ++ * the device reference to it, if it is a queue. Entities belonging to ++ * groups are not refcounted. ++ */ ++static void bfq_forget_entity(struct bfq_service_tree *st, ++ struct bfq_entity *entity) ++{ ++ struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity); ++ struct bfq_sched_data *sd; ++ ++ BUG_ON(!entity->on_st); ++ ++ entity->on_st = 0; ++ st->wsum -= entity->weight; ++ if (bfqq != NULL) { ++ sd = entity->sched_data; ++ bfq_log_bfqq(bfqq->bfqd, bfqq, "forget_entity: %p %d", ++ bfqq, atomic_read(&bfqq->ref)); ++ bfq_put_queue(bfqq); ++ } ++} ++ ++/** ++ * bfq_put_idle_entity - release the idle tree ref of an entity. ++ * @st: service tree for the entity. ++ * @entity: the entity being released. ++ */ ++static void bfq_put_idle_entity(struct bfq_service_tree *st, ++ struct bfq_entity *entity) ++{ ++ bfq_idle_extract(st, entity); ++ bfq_forget_entity(st, entity); ++} ++ ++/** ++ * bfq_forget_idle - update the idle tree if necessary. ++ * @st: the service tree to act upon. ++ * ++ * To preserve the global O(log N) complexity we only remove one entry here; ++ * as the idle tree will not grow indefinitely this can be done safely. ++ */ ++static void bfq_forget_idle(struct bfq_service_tree *st) ++{ ++ struct bfq_entity *first_idle = st->first_idle; ++ struct bfq_entity *last_idle = st->last_idle; ++ ++ if (RB_EMPTY_ROOT(&st->active) && last_idle != NULL && ++ !bfq_gt(last_idle->finish, st->vtime)) { ++ /* ++ * Forget the whole idle tree, increasing the vtime past ++ * the last finish time of idle entities. ++ */ ++ st->vtime = last_idle->finish; ++ } ++ ++ if (first_idle != NULL && !bfq_gt(first_idle->finish, st->vtime)) ++ bfq_put_idle_entity(st, first_idle); ++} ++ ++static struct bfq_service_tree * ++__bfq_entity_update_weight_prio(struct bfq_service_tree *old_st, ++ struct bfq_entity *entity) ++{ ++ struct bfq_service_tree *new_st = old_st; ++ ++ if (entity->ioprio_changed) { ++ struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity); ++ ++ BUG_ON(old_st->wsum < entity->weight); ++ old_st->wsum -= entity->weight; ++ ++ if (entity->new_weight != entity->orig_weight) { ++ entity->orig_weight = entity->new_weight; ++ entity->ioprio = ++ bfq_weight_to_ioprio(entity->orig_weight); ++ } else if (entity->new_ioprio != entity->ioprio) { ++ entity->ioprio = entity->new_ioprio; ++ entity->orig_weight = ++ bfq_ioprio_to_weight(entity->ioprio); ++ } else ++ entity->new_weight = entity->orig_weight = ++ bfq_ioprio_to_weight(entity->ioprio); ++ ++ entity->ioprio_class = entity->new_ioprio_class; ++ entity->ioprio_changed = 0; ++ ++ /* ++ * NOTE: here we may be changing the weight too early, ++ * this will cause unfairness. The correct approach ++ * would have required additional complexity to defer ++ * weight changes to the proper time instants (i.e., ++ * when entity->finish <= old_st->vtime). ++ */ ++ new_st = bfq_entity_service_tree(entity); ++ entity->weight = entity->orig_weight * ++ (bfqq != NULL ? bfqq->raising_coeff : 1); ++ new_st->wsum += entity->weight; ++ ++ if (new_st != old_st) ++ entity->start = new_st->vtime; ++ } ++ ++ return new_st; ++} ++ ++/** ++ * bfq_bfqq_served - update the scheduler status after selection for service. ++ * @bfqq: the queue being served. ++ * @served: bytes to transfer. ++ * ++ * NOTE: this can be optimized, as the timestamps of upper level entities ++ * are synchronized every time a new bfqq is selected for service. By now, ++ * we keep it to better check consistency. ++ */ ++static void bfq_bfqq_served(struct bfq_queue *bfqq, unsigned long served) ++{ ++ struct bfq_entity *entity = &bfqq->entity; ++ struct bfq_service_tree *st; ++ ++ for_each_entity(entity) { ++ st = bfq_entity_service_tree(entity); ++ ++ entity->service += served; ++ BUG_ON(entity->service > entity->budget); ++ BUG_ON(st->wsum == 0); ++ ++ st->vtime += bfq_delta(served, st->wsum); ++ bfq_forget_idle(st); ++ } ++ bfq_log_bfqq(bfqq->bfqd, bfqq, "bfqq_served %lu secs", served); ++} ++ ++/** ++ * bfq_bfqq_charge_full_budget - set the service to the entity budget. ++ * @bfqq: the queue that needs a service update. ++ * ++ * When it's not possible to be fair in the service domain, because ++ * a queue is not consuming its budget fast enough (the meaning of ++ * fast depends on the timeout parameter), we charge it a full ++ * budget. In this way we should obtain a sort of time-domain ++ * fairness among all the seeky/slow queues. ++ */ ++static inline void bfq_bfqq_charge_full_budget(struct bfq_queue *bfqq) ++{ ++ struct bfq_entity *entity = &bfqq->entity; ++ ++ bfq_log_bfqq(bfqq->bfqd, bfqq, "charge_full_budget"); ++ ++ bfq_bfqq_served(bfqq, entity->budget - entity->service); ++} ++ ++/** ++ * __bfq_activate_entity - activate an entity. ++ * @entity: the entity being activated. ++ * ++ * Called whenever an entity is activated, i.e., it is not active and one ++ * of its children receives a new request, or has to be reactivated due to ++ * budget exhaustion. It uses the current budget of the entity (and the ++ * service received if @entity is active) of the queue to calculate its ++ * timestamps. ++ */ ++static void __bfq_activate_entity(struct bfq_entity *entity) ++{ ++ struct bfq_sched_data *sd = entity->sched_data; ++ struct bfq_service_tree *st = bfq_entity_service_tree(entity); ++ ++ if (entity == sd->active_entity) { ++ BUG_ON(entity->tree != NULL); ++ /* ++ * If we are requeueing the current entity we have ++ * to take care of not charging to it service it has ++ * not received. ++ */ ++ bfq_calc_finish(entity, entity->service); ++ entity->start = entity->finish; ++ sd->active_entity = NULL; ++ } else if (entity->tree == &st->active) { ++ /* ++ * Requeueing an entity due to a change of some ++ * next_active entity below it. We reuse the old ++ * start time. ++ */ ++ bfq_active_extract(st, entity); ++ } else if (entity->tree == &st->idle) { ++ /* ++ * Must be on the idle tree, bfq_idle_extract() will ++ * check for that. ++ */ ++ bfq_idle_extract(st, entity); ++ entity->start = bfq_gt(st->vtime, entity->finish) ? ++ st->vtime : entity->finish; ++ } else { ++ /* ++ * The finish time of the entity may be invalid, and ++ * it is in the past for sure, otherwise the queue ++ * would have been on the idle tree. ++ */ ++ entity->start = st->vtime; ++ st->wsum += entity->weight; ++ bfq_get_entity(entity); ++ ++ BUG_ON(entity->on_st); ++ entity->on_st = 1; ++ } ++ ++ st = __bfq_entity_update_weight_prio(st, entity); ++ bfq_calc_finish(entity, entity->budget); ++ bfq_active_insert(st, entity); ++} ++ ++/** ++ * bfq_activate_entity - activate an entity and its ancestors if necessary. ++ * @entity: the entity to activate. ++ * ++ * Activate @entity and all the entities on the path from it to the root. ++ */ ++static void bfq_activate_entity(struct bfq_entity *entity) ++{ ++ struct bfq_sched_data *sd; ++ ++ for_each_entity(entity) { ++ __bfq_activate_entity(entity); ++ ++ sd = entity->sched_data; ++ if (!bfq_update_next_active(sd)) ++ /* ++ * No need to propagate the activation to the ++ * upper entities, as they will be updated when ++ * the active entity is rescheduled. ++ */ ++ break; ++ } ++} ++ ++/** ++ * __bfq_deactivate_entity - deactivate an entity from its service tree. ++ * @entity: the entity to deactivate. ++ * @requeue: if false, the entity will not be put into the idle tree. ++ * ++ * Deactivate an entity, independently from its previous state. If the ++ * entity was not on a service tree just return, otherwise if it is on ++ * any scheduler tree, extract it from that tree, and if necessary ++ * and if the caller did not specify @requeue, put it on the idle tree. ++ * ++ * Return %1 if the caller should update the entity hierarchy, i.e., ++ * if the entity was under service or if it was the next_active for ++ * its sched_data; return %0 otherwise. ++ */ ++static int __bfq_deactivate_entity(struct bfq_entity *entity, int requeue) ++{ ++ struct bfq_sched_data *sd = entity->sched_data; ++ struct bfq_service_tree *st = bfq_entity_service_tree(entity); ++ int was_active = entity == sd->active_entity; ++ int ret = 0; ++ ++ if (!entity->on_st) ++ return 0; ++ ++ BUG_ON(was_active && entity->tree != NULL); ++ ++ if (was_active) { ++ bfq_calc_finish(entity, entity->service); ++ sd->active_entity = NULL; ++ } else if (entity->tree == &st->active) ++ bfq_active_extract(st, entity); ++ else if (entity->tree == &st->idle) ++ bfq_idle_extract(st, entity); ++ else if (entity->tree != NULL) ++ BUG(); ++ ++ if (was_active || sd->next_active == entity) ++ ret = bfq_update_next_active(sd); ++ ++ if (!requeue || !bfq_gt(entity->finish, st->vtime)) ++ bfq_forget_entity(st, entity); ++ else ++ bfq_idle_insert(st, entity); ++ ++ BUG_ON(sd->active_entity == entity); ++ BUG_ON(sd->next_active == entity); ++ ++ return ret; ++} ++ ++/** ++ * bfq_deactivate_entity - deactivate an entity. ++ * @entity: the entity to deactivate. ++ * @requeue: true if the entity can be put on the idle tree ++ */ ++static void bfq_deactivate_entity(struct bfq_entity *entity, int requeue) ++{ ++ struct bfq_sched_data *sd; ++ struct bfq_entity *parent; ++ ++ for_each_entity_safe(entity, parent) { ++ sd = entity->sched_data; ++ ++ if (!__bfq_deactivate_entity(entity, requeue)) ++ /* ++ * The parent entity is still backlogged, and ++ * we don't need to update it as it is still ++ * under service. ++ */ ++ break; ++ ++ if (sd->next_active != NULL) ++ /* ++ * The parent entity is still backlogged and ++ * the budgets on the path towards the root ++ * need to be updated. ++ */ ++ goto update; ++ ++ /* ++ * If we reach there the parent is no more backlogged and ++ * we want to propagate the dequeue upwards. ++ */ ++ requeue = 1; ++ } ++ ++ return; ++ ++update: ++ entity = parent; ++ for_each_entity(entity) { ++ __bfq_activate_entity(entity); ++ ++ sd = entity->sched_data; ++ if (!bfq_update_next_active(sd)) ++ break; ++ } ++} ++ ++/** ++ * bfq_update_vtime - update vtime if necessary. ++ * @st: the service tree to act upon. ++ * ++ * If necessary update the service tree vtime to have at least one ++ * eligible entity, skipping to its start time. Assumes that the ++ * active tree of the device is not empty. ++ * ++ * NOTE: this hierarchical implementation updates vtimes quite often, ++ * we may end up with reactivated tasks getting timestamps after a ++ * vtime skip done because we needed a ->first_active entity on some ++ * intermediate node. ++ */ ++static void bfq_update_vtime(struct bfq_service_tree *st) ++{ ++ struct bfq_entity *entry; ++ struct rb_node *node = st->active.rb_node; ++ ++ entry = rb_entry(node, struct bfq_entity, rb_node); ++ if (bfq_gt(entry->min_start, st->vtime)) { ++ st->vtime = entry->min_start; ++ bfq_forget_idle(st); ++ } ++} ++ ++/** ++ * bfq_first_active - find the eligible entity with the smallest finish time ++ * @st: the service tree to select from. ++ * ++ * This function searches the first schedulable entity, starting from the ++ * root of the tree and going on the left every time on this side there is ++ * a subtree with at least one eligible (start >= vtime) entity. The path ++ * on the right is followed only if a) the left subtree contains no eligible ++ * entities and b) no eligible entity has been found yet. ++ */ ++static struct bfq_entity *bfq_first_active_entity(struct bfq_service_tree *st) ++{ ++ struct bfq_entity *entry, *first = NULL; ++ struct rb_node *node = st->active.rb_node; ++ ++ while (node != NULL) { ++ entry = rb_entry(node, struct bfq_entity, rb_node); ++left: ++ if (!bfq_gt(entry->start, st->vtime)) ++ first = entry; ++ ++ BUG_ON(bfq_gt(entry->min_start, st->vtime)); ++ ++ if (node->rb_left != NULL) { ++ entry = rb_entry(node->rb_left, ++ struct bfq_entity, rb_node); ++ if (!bfq_gt(entry->min_start, st->vtime)) { ++ node = node->rb_left; ++ goto left; ++ } ++ } ++ if (first != NULL) ++ break; ++ node = node->rb_right; ++ } ++ ++ BUG_ON(first == NULL && !RB_EMPTY_ROOT(&st->active)); ++ return first; ++} ++ ++/** ++ * __bfq_lookup_next_entity - return the first eligible entity in @st. ++ * @st: the service tree. ++ * ++ * Update the virtual time in @st and return the first eligible entity ++ * it contains. ++ */ ++static struct bfq_entity *__bfq_lookup_next_entity(struct bfq_service_tree *st, ++ bool force) ++{ ++ struct bfq_entity *entity, *new_next_active = NULL; ++ ++ if (RB_EMPTY_ROOT(&st->active)) ++ return NULL; ++ ++ bfq_update_vtime(st); ++ entity = bfq_first_active_entity(st); ++ BUG_ON(bfq_gt(entity->start, st->vtime)); ++ ++ /* ++ * If the chosen entity does not match with the sched_data's ++ * next_active and we are forcedly serving the IDLE priority ++ * class tree, bubble up budget update. ++ */ ++ if (unlikely(force && entity != entity->sched_data->next_active)) { ++ new_next_active = entity; ++ for_each_entity(new_next_active) ++ bfq_update_budget(new_next_active); ++ } ++ ++ return entity; ++} ++ ++/** ++ * bfq_lookup_next_entity - return the first eligible entity in @sd. ++ * @sd: the sched_data. ++ * @extract: if true the returned entity will be also extracted from @sd. ++ * ++ * NOTE: since we cache the next_active entity at each level of the ++ * hierarchy, the complexity of the lookup can be decreased with ++ * absolutely no effort just returning the cached next_active value; ++ * we prefer to do full lookups to test the consistency of * the data ++ * structures. ++ */ ++static struct bfq_entity *bfq_lookup_next_entity(struct bfq_sched_data *sd, ++ int extract, ++ struct bfq_data *bfqd) ++{ ++ struct bfq_service_tree *st = sd->service_tree; ++ struct bfq_entity *entity; ++ int i=0; ++ ++ BUG_ON(sd->active_entity != NULL); ++ ++ if (bfqd != NULL && ++ jiffies - bfqd->bfq_class_idle_last_service > BFQ_CL_IDLE_TIMEOUT) { ++ entity = __bfq_lookup_next_entity(st + BFQ_IOPRIO_CLASSES - 1, true); ++ if (entity != NULL) { ++ i = BFQ_IOPRIO_CLASSES - 1; ++ bfqd->bfq_class_idle_last_service = jiffies; ++ sd->next_active = entity; ++ } ++ } ++ for (; i < BFQ_IOPRIO_CLASSES; i++) { ++ entity = __bfq_lookup_next_entity(st + i, false); ++ if (entity != NULL) { ++ if (extract) { ++ bfq_check_next_active(sd, entity); ++ bfq_active_extract(st + i, entity); ++ sd->active_entity = entity; ++ sd->next_active = NULL; ++ } ++ break; ++ } ++ } ++ ++ return entity; ++} ++ ++/* ++ * Get next queue for service. ++ */ ++static struct bfq_queue *bfq_get_next_queue(struct bfq_data *bfqd) ++{ ++ struct bfq_entity *entity = NULL; ++ struct bfq_sched_data *sd; ++ struct bfq_queue *bfqq; ++ ++ BUG_ON(bfqd->active_queue != NULL); ++ ++ if (bfqd->busy_queues == 0) ++ return NULL; ++ ++ sd = &bfqd->root_group->sched_data; ++ for (; sd != NULL; sd = entity->my_sched_data) { ++ entity = bfq_lookup_next_entity(sd, 1, bfqd); ++ BUG_ON(entity == NULL); ++ entity->service = 0; ++ } ++ ++ bfqq = bfq_entity_to_bfqq(entity); ++ BUG_ON(bfqq == NULL); ++ ++ return bfqq; ++} ++ ++static void __bfq_bfqd_reset_active(struct bfq_data *bfqd) ++{ ++ if (bfqd->active_bic != NULL) { ++ put_io_context(bfqd->active_bic->icq.ioc); ++ bfqd->active_bic = NULL; ++ } ++ ++ bfqd->active_queue = NULL; ++ del_timer(&bfqd->idle_slice_timer); ++} ++ ++static void bfq_deactivate_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq, ++ int requeue) ++{ ++ struct bfq_entity *entity = &bfqq->entity; ++ ++ if (bfqq == bfqd->active_queue) ++ __bfq_bfqd_reset_active(bfqd); ++ ++ bfq_deactivate_entity(entity, requeue); ++} ++ ++static void bfq_activate_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq) ++{ ++ struct bfq_entity *entity = &bfqq->entity; ++ ++ bfq_activate_entity(entity); ++} ++ ++/* ++ * Called when the bfqq no longer has requests pending, remove it from ++ * the service tree. ++ */ ++static void bfq_del_bfqq_busy(struct bfq_data *bfqd, struct bfq_queue *bfqq, ++ int requeue) ++{ ++ BUG_ON(!bfq_bfqq_busy(bfqq)); ++ BUG_ON(!RB_EMPTY_ROOT(&bfqq->sort_list)); ++ ++ bfq_log_bfqq(bfqd, bfqq, "del from busy"); ++ ++ bfq_clear_bfqq_busy(bfqq); ++ ++ BUG_ON(bfqd->busy_queues == 0); ++ bfqd->busy_queues--; ++ ++ bfq_deactivate_bfqq(bfqd, bfqq, requeue); ++} ++ ++/* ++ * Called when an inactive queue receives a new request. ++ */ ++static void bfq_add_bfqq_busy(struct bfq_data *bfqd, struct bfq_queue *bfqq) ++{ ++ BUG_ON(bfq_bfqq_busy(bfqq)); ++ BUG_ON(bfqq == bfqd->active_queue); ++ ++ bfq_log_bfqq(bfqd, bfqq, "add to busy"); ++ ++ bfq_activate_bfqq(bfqd, bfqq); ++ ++ bfq_mark_bfqq_busy(bfqq); ++ bfqd->busy_queues++; ++} +diff --git a/block/bfq.h b/block/bfq.h +new file mode 100644 +index 0000000..ce3c474 +--- /dev/null ++++ b/block/bfq.h +@@ -0,0 +1,617 @@ ++/* ++ * BFQ-v5r1 for 3.7.0: data structures and common functions prototypes. ++ * ++ * Based on ideas and code from CFQ: ++ * Copyright (C) 2003 Jens Axboe ++ * ++ * Copyright (C) 2008 Fabio Checconi ++ * Paolo Valente ++ * ++ * Copyright (C) 2010 Paolo Valente ++ */ ++ ++#ifndef _BFQ_H ++#define _BFQ_H ++ ++#include ++#include ++#include ++#include ++ ++#define BFQ_IOPRIO_CLASSES 3 ++#define BFQ_CL_IDLE_TIMEOUT HZ/5 ++ ++#define BFQ_MIN_WEIGHT 1 ++#define BFQ_MAX_WEIGHT 1000 ++ ++#define BFQ_DEFAULT_GRP_WEIGHT 10 ++#define BFQ_DEFAULT_GRP_IOPRIO 0 ++#define BFQ_DEFAULT_GRP_CLASS IOPRIO_CLASS_BE ++ ++struct bfq_entity; ++ ++/** ++ * struct bfq_service_tree - per ioprio_class service tree. ++ * @active: tree for active entities (i.e., those backlogged). ++ * @idle: tree for idle entities (i.e., those not backlogged, with V <= F_i). ++ * @first_idle: idle entity with minimum F_i. ++ * @last_idle: idle entity with maximum F_i. ++ * @vtime: scheduler virtual time. ++ * @wsum: scheduler weight sum; active and idle entities contribute to it. ++ * ++ * Each service tree represents a B-WF2Q+ scheduler on its own. Each ++ * ioprio_class has its own independent scheduler, and so its own ++ * bfq_service_tree. All the fields are protected by the queue lock ++ * of the containing bfqd. ++ */ ++struct bfq_service_tree { ++ struct rb_root active; ++ struct rb_root idle; ++ ++ struct bfq_entity *first_idle; ++ struct bfq_entity *last_idle; ++ ++ u64 vtime; ++ unsigned long wsum; ++}; ++ ++/** ++ * struct bfq_sched_data - multi-class scheduler. ++ * @active_entity: entity under service. ++ * @next_active: head-of-the-line entity in the scheduler. ++ * @service_tree: array of service trees, one per ioprio_class. ++ * ++ * bfq_sched_data is the basic scheduler queue. It supports three ++ * ioprio_classes, and can be used either as a toplevel queue or as ++ * an intermediate queue on a hierarchical setup. ++ * @next_active points to the active entity of the sched_data service ++ * trees that will be scheduled next. ++ * ++ * The supported ioprio_classes are the same as in CFQ, in descending ++ * priority order, IOPRIO_CLASS_RT, IOPRIO_CLASS_BE, IOPRIO_CLASS_IDLE. ++ * Requests from higher priority queues are served before all the ++ * requests from lower priority queues; among requests of the same ++ * queue requests are served according to B-WF2Q+. ++ * All the fields are protected by the queue lock of the containing bfqd. ++ */ ++struct bfq_sched_data { ++ struct bfq_entity *active_entity; ++ struct bfq_entity *next_active; ++ struct bfq_service_tree service_tree[BFQ_IOPRIO_CLASSES]; ++}; ++ ++/** ++ * struct bfq_entity - schedulable entity. ++ * @rb_node: service_tree member. ++ * @on_st: flag, true if the entity is on a tree (either the active or ++ * the idle one of its service_tree). ++ * @finish: B-WF2Q+ finish timestamp (aka F_i). ++ * @start: B-WF2Q+ start timestamp (aka S_i). ++ * @tree: tree the entity is enqueued into; %NULL if not on a tree. ++ * @min_start: minimum start time of the (active) subtree rooted at ++ * this entity; used for O(log N) lookups into active trees. ++ * @service: service received during the last round of service. ++ * @budget: budget used to calculate F_i; F_i = S_i + @budget / @weight. ++ * @weight: weight of the queue ++ * @parent: parent entity, for hierarchical scheduling. ++ * @my_sched_data: for non-leaf nodes in the cgroup hierarchy, the ++ * associated scheduler queue, %NULL on leaf nodes. ++ * @sched_data: the scheduler queue this entity belongs to. ++ * @ioprio: the ioprio in use. ++ * @new_weight: when a weight change is requested, the new weight value. ++ * @orig_weight: original weight, used to implement weight boosting ++ * @new_ioprio: when an ioprio change is requested, the new ioprio value. ++ * @ioprio_class: the ioprio_class in use. ++ * @new_ioprio_class: when an ioprio_class change is requested, the new ++ * ioprio_class value. ++ * @ioprio_changed: flag, true when the user requested a weight, ioprio or ++ * ioprio_class change. ++ * ++ * A bfq_entity is used to represent either a bfq_queue (leaf node in the ++ * cgroup hierarchy) or a bfq_group into the upper level scheduler. Each ++ * entity belongs to the sched_data of the parent group in the cgroup ++ * hierarchy. Non-leaf entities have also their own sched_data, stored ++ * in @my_sched_data. ++ * ++ * Each entity stores independently its priority values; this would ++ * allow different weights on different devices, but this ++ * functionality is not exported to userspace by now. Priorities and ++ * weights are updated lazily, first storing the new values into the ++ * new_* fields, then setting the @ioprio_changed flag. As soon as ++ * there is a transition in the entity state that allows the priority ++ * update to take place the effective and the requested priority ++ * values are synchronized. ++ * ++ * Unless cgroups are used, the weight value is calculated from the ++ * ioprio to export the same interface as CFQ. When dealing with ++ * ``well-behaved'' queues (i.e., queues that do not spend too much ++ * time to consume their budget and have true sequential behavior, and ++ * when there are no external factors breaking anticipation) the ++ * relative weights at each level of the cgroups hierarchy should be ++ * guaranteed. All the fields are protected by the queue lock of the ++ * containing bfqd. ++ */ ++struct bfq_entity { ++ struct rb_node rb_node; ++ ++ int on_st; ++ ++ u64 finish; ++ u64 start; ++ ++ struct rb_root *tree; ++ ++ u64 min_start; ++ ++ unsigned long service, budget; ++ unsigned short weight, new_weight; ++ unsigned short orig_weight; ++ ++ struct bfq_entity *parent; ++ ++ struct bfq_sched_data *my_sched_data; ++ struct bfq_sched_data *sched_data; ++ ++ unsigned short ioprio, new_ioprio; ++ unsigned short ioprio_class, new_ioprio_class; ++ ++ int ioprio_changed; ++}; ++ ++struct bfq_group; ++ ++/** ++ * struct bfq_queue - leaf schedulable entity. ++ * @ref: reference counter. ++ * @bfqd: parent bfq_data. ++ * @new_bfqq: shared bfq_queue if queue is cooperating with ++ * one or more other queues. ++ * @pos_node: request-position tree member (see bfq_data's @rq_pos_tree). ++ * @pos_root: request-position tree root (see bfq_data's @rq_pos_tree). ++ * @sort_list: sorted list of pending requests. ++ * @next_rq: if fifo isn't expired, next request to serve. ++ * @queued: nr of requests queued in @sort_list. ++ * @allocated: currently allocated requests. ++ * @meta_pending: pending metadata requests. ++ * @fifo: fifo list of requests in sort_list. ++ * @entity: entity representing this queue in the scheduler. ++ * @max_budget: maximum budget allowed from the feedback mechanism. ++ * @budget_timeout: budget expiration (in jiffies). ++ * @dispatched: number of requests on the dispatch list or inside driver. ++ * @org_ioprio: saved ioprio during boosted periods. ++ * @flags: status flags. ++ * @bfqq_list: node for active/idle bfqq list inside our bfqd. ++ * @seek_samples: number of seeks sampled ++ * @seek_total: sum of the distances of the seeks sampled ++ * @seek_mean: mean seek distance ++ * @last_request_pos: position of the last request enqueued ++ * @pid: pid of the process owning the queue, used for logging purposes. ++ * @last_rais_start_time: last (idle -> weight-raised) transition attempt ++ * @raising_cur_max_time: current max raising time for this queue ++ * @bic: pointer to the bfq_io_cq owning the bfq_queue, set to %NULL if the ++ * queue is shared ++ * ++ * A bfq_queue is a leaf request queue; it can be associated to an io_context ++ * or more (if it is an async one). @cgroup holds a reference to the ++ * cgroup, to be sure that it does not disappear while a bfqq still ++ * references it (mostly to avoid races between request issuing and task ++ * migration followed by cgroup distruction). ++ * All the fields are protected by the queue lock of the containing bfqd. ++ */ ++struct bfq_queue { ++ atomic_t ref; ++ struct bfq_data *bfqd; ++ ++ /* fields for cooperating queues handling */ ++ struct bfq_queue *new_bfqq; ++ struct rb_node pos_node; ++ struct rb_root *pos_root; ++ ++ struct rb_root sort_list; ++ struct request *next_rq; ++ int queued[2]; ++ int allocated[2]; ++ int meta_pending; ++ struct list_head fifo; ++ ++ struct bfq_entity entity; ++ ++ unsigned long max_budget; ++ unsigned long budget_timeout; ++ ++ int dispatched; ++ ++ unsigned short org_ioprio; ++ ++ unsigned int flags; ++ ++ struct list_head bfqq_list; ++ ++ unsigned int seek_samples; ++ u64 seek_total; ++ sector_t seek_mean; ++ sector_t last_request_pos; ++ ++ pid_t pid; ++ struct bfq_io_cq *bic; ++ ++ /* weight-raising fields */ ++ unsigned int raising_cur_max_time; ++ u64 last_rais_start_finish, soft_rt_next_start; ++ unsigned int raising_coeff; ++}; ++ ++/** ++ * struct bfq_ttime - per process thinktime stats. ++ * @ttime_total: total process thinktime ++ * @ttime_samples: number of thinktime samples ++ * @ttime_mean: average process thinktime ++ */ ++struct bfq_ttime { ++ unsigned long last_end_request; ++ ++ unsigned long ttime_total; ++ unsigned long ttime_samples; ++ unsigned long ttime_mean; ++}; ++ ++/** ++ * struct bfq_io_cq - per (request_queue, io_context) structure. ++ * @icq: associated io_cq structure ++ * @bfqq: array of two process queues, the sync and the async ++ * @ttime: associated @bfq_ttime struct ++ * @raising_time_left: snapshot of the time left before weight raising ends ++ * for the sync queue associated to this process; this ++ * snapshot is taken to remember this value while the weight ++ * raising is suspended because the queue is merged with a ++ * shared queue, and is used to set @raising_cur_max_time ++ * when the queue is split from the shared queue and its ++ * weight is raised again ++ * @saved_idle_window: same purpose as the previous field for the idle window ++ */ ++struct bfq_io_cq { ++ struct io_cq icq; /* must be the first member */ ++ struct bfq_queue *bfqq[2]; ++ struct bfq_ttime ttime; ++ int ioprio; ++ ++ unsigned int raising_time_left; ++ unsigned int saved_idle_window; ++}; ++ ++/** ++ * struct bfq_data - per device data structure. ++ * @queue: request queue for the managed device. ++ * @root_group: root bfq_group for the device. ++ * @rq_pos_tree: rbtree sorted by next_request position, ++ * used when determining if two or more queues ++ * have interleaving requests (see bfq_close_cooperator). ++ * @busy_queues: number of bfq_queues containing requests (including the ++ * queue under service, even if it is idling). ++ * @queued: number of queued requests. ++ * @rq_in_driver: number of requests dispatched and waiting for completion. ++ * @sync_flight: number of sync requests in the driver. ++ * @max_rq_in_driver: max number of reqs in driver in the last @hw_tag_samples ++ * completed requests . ++ * @hw_tag_samples: nr of samples used to calculate hw_tag. ++ * @hw_tag: flag set to one if the driver is showing a queueing behavior. ++ * @budgets_assigned: number of budgets assigned. ++ * @idle_slice_timer: timer set when idling for the next sequential request ++ * from the queue under service. ++ * @unplug_work: delayed work to restart dispatching on the request queue. ++ * @active_queue: bfq_queue under service. ++ * @active_bic: bfq_io_cq (bic) associated with the @active_queue. ++ * @last_position: on-disk position of the last served request. ++ * @last_budget_start: beginning of the last budget. ++ * @last_idling_start: beginning of the last idle slice. ++ * @peak_rate: peak transfer rate observed for a budget. ++ * @peak_rate_samples: number of samples used to calculate @peak_rate. ++ * @bfq_max_budget: maximum budget allotted to a bfq_queue before rescheduling. ++ * @group_list: list of all the bfq_groups active on the device. ++ * @active_list: list of all the bfq_queues active on the device. ++ * @idle_list: list of all the bfq_queues idle on the device. ++ * @bfq_quantum: max number of requests dispatched per dispatch round. ++ * @bfq_fifo_expire: timeout for async/sync requests; when it expires ++ * requests are served in fifo order. ++ * @bfq_back_penalty: weight of backward seeks wrt forward ones. ++ * @bfq_back_max: maximum allowed backward seek. ++ * @bfq_slice_idle: maximum idling time. ++ * @bfq_user_max_budget: user-configured max budget value (0 for auto-tuning). ++ * @bfq_max_budget_async_rq: maximum budget (in nr of requests) allotted to ++ * async queues. ++ * @bfq_timeout: timeout for bfq_queues to consume their budget; used to ++ * to prevent seeky queues to impose long latencies to well ++ * behaved ones (this also implies that seeky queues cannot ++ * receive guarantees in the service domain; after a timeout ++ * they are charged for the whole allocated budget, to try ++ * to preserve a behavior reasonably fair among them, but ++ * without service-domain guarantees). ++ * @bfq_raising_coeff: Maximum factor by which the weight of a boosted ++ * queue is multiplied ++ * @bfq_raising_max_time: maximum duration of a weight-raising period (jiffies) ++ * @bfq_raising_rt_max_time: maximum duration for soft real-time processes ++ * @bfq_raising_min_idle_time: minimum idle period after which weight-raising ++ * may be reactivated for a queue (in jiffies) ++ * @bfq_raising_min_inter_arr_async: minimum period between request arrivals ++ * after which weight-raising may be ++ * reactivated for an already busy queue ++ * (in jiffies) ++ * @bfq_raising_max_softrt_rate: max service-rate for a soft real-time queue, ++ * sectors per seconds ++ * @RT_prod: cached value of the product R*T used for computing the maximum ++ * duration of the weight raising automatically ++ * @oom_bfqq: fallback dummy bfqq for extreme OOM conditions ++ * ++ * All the fields are protected by the @queue lock. ++ */ ++struct bfq_data { ++ struct request_queue *queue; ++ ++ struct bfq_group *root_group; ++ ++ struct rb_root rq_pos_tree; ++ ++ int busy_queues; ++ int queued; ++ int rq_in_driver; ++ int sync_flight; ++ ++ int max_rq_in_driver; ++ int hw_tag_samples; ++ int hw_tag; ++ ++ int budgets_assigned; ++ ++ struct timer_list idle_slice_timer; ++ struct work_struct unplug_work; ++ ++ struct bfq_queue *active_queue; ++ struct bfq_io_cq *active_bic; ++ ++ sector_t last_position; ++ ++ ktime_t last_budget_start; ++ ktime_t last_idling_start; ++ int peak_rate_samples; ++ u64 peak_rate; ++ unsigned long bfq_max_budget; ++ ++ struct hlist_head group_list; ++ struct list_head active_list; ++ struct list_head idle_list; ++ ++ unsigned int bfq_quantum; ++ unsigned int bfq_fifo_expire[2]; ++ unsigned int bfq_back_penalty; ++ unsigned int bfq_back_max; ++ unsigned int bfq_slice_idle; ++ u64 bfq_class_idle_last_service; ++ ++ unsigned int bfq_user_max_budget; ++ unsigned int bfq_max_budget_async_rq; ++ unsigned int bfq_timeout[2]; ++ ++ bool low_latency; ++ ++ /* parameters of the low_latency heuristics */ ++ unsigned int bfq_raising_coeff; ++ unsigned int bfq_raising_max_time; ++ unsigned int bfq_raising_rt_max_time; ++ unsigned int bfq_raising_min_idle_time; ++ unsigned int bfq_raising_min_inter_arr_async; ++ unsigned int bfq_raising_max_softrt_rate; ++ u64 RT_prod; ++ ++ struct bfq_queue oom_bfqq; ++}; ++ ++enum bfqq_state_flags { ++ BFQ_BFQQ_FLAG_busy = 0, /* has requests or is under service */ ++ BFQ_BFQQ_FLAG_wait_request, /* waiting for a request */ ++ BFQ_BFQQ_FLAG_must_alloc, /* must be allowed rq alloc */ ++ BFQ_BFQQ_FLAG_fifo_expire, /* FIFO checked in this slice */ ++ BFQ_BFQQ_FLAG_idle_window, /* slice idling enabled */ ++ BFQ_BFQQ_FLAG_prio_changed, /* task priority has changed */ ++ BFQ_BFQQ_FLAG_sync, /* synchronous queue */ ++ BFQ_BFQQ_FLAG_budget_new, /* no completion with this budget */ ++ BFQ_BFQQ_FLAG_coop, /* bfqq is shared */ ++ BFQ_BFQQ_FLAG_split_coop, /* shared bfqq will be splitted */ ++ BFQ_BFQQ_FLAG_some_coop_idle, /* some cooperator is inactive */ ++ BFQ_BFQQ_FLAG_just_split, /* queue has just been split */ ++}; ++ ++#define BFQ_BFQQ_FNS(name) \ ++static inline void bfq_mark_bfqq_##name(struct bfq_queue *bfqq) \ ++{ \ ++ (bfqq)->flags |= (1 << BFQ_BFQQ_FLAG_##name); \ ++} \ ++static inline void bfq_clear_bfqq_##name(struct bfq_queue *bfqq) \ ++{ \ ++ (bfqq)->flags &= ~(1 << BFQ_BFQQ_FLAG_##name); \ ++} \ ++static inline int bfq_bfqq_##name(const struct bfq_queue *bfqq) \ ++{ \ ++ return ((bfqq)->flags & (1 << BFQ_BFQQ_FLAG_##name)) != 0; \ ++} ++ ++BFQ_BFQQ_FNS(busy); ++BFQ_BFQQ_FNS(wait_request); ++BFQ_BFQQ_FNS(must_alloc); ++BFQ_BFQQ_FNS(fifo_expire); ++BFQ_BFQQ_FNS(idle_window); ++BFQ_BFQQ_FNS(prio_changed); ++BFQ_BFQQ_FNS(sync); ++BFQ_BFQQ_FNS(budget_new); ++BFQ_BFQQ_FNS(coop); ++BFQ_BFQQ_FNS(split_coop); ++BFQ_BFQQ_FNS(some_coop_idle); ++BFQ_BFQQ_FNS(just_split); ++#undef BFQ_BFQQ_FNS ++ ++/* Logging facilities. */ ++#define bfq_log_bfqq(bfqd, bfqq, fmt, args...) \ ++ blk_add_trace_msg((bfqd)->queue, "bfq%d " fmt, (bfqq)->pid, ##args) ++ ++#define bfq_log(bfqd, fmt, args...) \ ++ blk_add_trace_msg((bfqd)->queue, "bfq " fmt, ##args) ++ ++/* Expiration reasons. */ ++enum bfqq_expiration { ++ BFQ_BFQQ_TOO_IDLE = 0, /* queue has been idling for too long */ ++ BFQ_BFQQ_BUDGET_TIMEOUT, /* budget took too long to be used */ ++ BFQ_BFQQ_BUDGET_EXHAUSTED, /* budget consumed */ ++ BFQ_BFQQ_NO_MORE_REQUESTS, /* the queue has no more requests */ ++}; ++ ++#ifdef CONFIG_CGROUP_BFQIO ++/** ++ * struct bfq_group - per (device, cgroup) data structure. ++ * @entity: schedulable entity to insert into the parent group sched_data. ++ * @sched_data: own sched_data, to contain child entities (they may be ++ * both bfq_queues and bfq_groups). ++ * @group_node: node to be inserted into the bfqio_cgroup->group_data ++ * list of the containing cgroup's bfqio_cgroup. ++ * @bfqd_node: node to be inserted into the @bfqd->group_list list ++ * of the groups active on the same device; used for cleanup. ++ * @bfqd: the bfq_data for the device this group acts upon. ++ * @async_bfqq: array of async queues for all the tasks belonging to ++ * the group, one queue per ioprio value per ioprio_class, ++ * except for the idle class that has only one queue. ++ * @async_idle_bfqq: async queue for the idle class (ioprio is ignored). ++ * @my_entity: pointer to @entity, %NULL for the toplevel group; used ++ * to avoid too many special cases during group creation/migration. ++ * ++ * Each (device, cgroup) pair has its own bfq_group, i.e., for each cgroup ++ * there is a set of bfq_groups, each one collecting the lower-level ++ * entities belonging to the group that are acting on the same device. ++ * ++ * Locking works as follows: ++ * o @group_node is protected by the bfqio_cgroup lock, and is accessed ++ * via RCU from its readers. ++ * o @bfqd is protected by the queue lock, RCU is used to access it ++ * from the readers. ++ * o All the other fields are protected by the @bfqd queue lock. ++ */ ++struct bfq_group { ++ struct bfq_entity entity; ++ struct bfq_sched_data sched_data; ++ ++ struct hlist_node group_node; ++ struct hlist_node bfqd_node; ++ ++ void *bfqd; ++ ++ struct bfq_queue *async_bfqq[2][IOPRIO_BE_NR]; ++ struct bfq_queue *async_idle_bfqq; ++ ++ struct bfq_entity *my_entity; ++}; ++ ++/** ++ * struct bfqio_cgroup - bfq cgroup data structure. ++ * @css: subsystem state for bfq in the containing cgroup. ++ * @weight: cgroup weight. ++ * @ioprio: cgroup ioprio. ++ * @ioprio_class: cgroup ioprio_class. ++ * @lock: spinlock that protects @ioprio, @ioprio_class and @group_data. ++ * @group_data: list containing the bfq_group belonging to this cgroup. ++ * ++ * @group_data is accessed using RCU, with @lock protecting the updates, ++ * @ioprio and @ioprio_class are protected by @lock. ++ */ ++struct bfqio_cgroup { ++ struct cgroup_subsys_state css; ++ ++ unsigned short weight, ioprio, ioprio_class; ++ ++ spinlock_t lock; ++ struct hlist_head group_data; ++}; ++#else ++struct bfq_group { ++ struct bfq_sched_data sched_data; ++ ++ struct bfq_queue *async_bfqq[2][IOPRIO_BE_NR]; ++ struct bfq_queue *async_idle_bfqq; ++}; ++#endif ++ ++static inline struct bfq_service_tree * ++bfq_entity_service_tree(struct bfq_entity *entity) ++{ ++ struct bfq_sched_data *sched_data = entity->sched_data; ++ unsigned int idx = entity->ioprio_class - 1; ++ ++ BUG_ON(idx >= BFQ_IOPRIO_CLASSES); ++ BUG_ON(sched_data == NULL); ++ ++ return sched_data->service_tree + idx; ++} ++ ++static inline struct bfq_queue *bic_to_bfqq(struct bfq_io_cq *bic, ++ int is_sync) ++{ ++ return bic->bfqq[!!is_sync]; ++} ++ ++static inline void bic_set_bfqq(struct bfq_io_cq *bic, ++ struct bfq_queue *bfqq, int is_sync) ++{ ++ bic->bfqq[!!is_sync] = bfqq; ++} ++ ++static inline struct bfq_data *bic_to_bfqd(struct bfq_io_cq *bic) ++{ ++ return bic->icq.q->elevator->elevator_data; ++} ++ ++/** ++ * bfq_get_bfqd_locked - get a lock to a bfqd using a RCU protected pointer. ++ * @ptr: a pointer to a bfqd. ++ * @flags: storage for the flags to be saved. ++ * ++ * This function allows bfqg->bfqd to be protected by the ++ * queue lock of the bfqd they reference; the pointer is dereferenced ++ * under RCU, so the storage for bfqd is assured to be safe as long ++ * as the RCU read side critical section does not end. After the ++ * bfqd->queue->queue_lock is taken the pointer is rechecked, to be ++ * sure that no other writer accessed it. If we raced with a writer, ++ * the function returns NULL, with the queue unlocked, otherwise it ++ * returns the dereferenced pointer, with the queue locked. ++ */ ++static inline struct bfq_data *bfq_get_bfqd_locked(void **ptr, ++ unsigned long *flags) ++{ ++ struct bfq_data *bfqd; ++ ++ rcu_read_lock(); ++ bfqd = rcu_dereference(*(struct bfq_data **)ptr); ++ ++ if (bfqd != NULL) { ++ spin_lock_irqsave(bfqd->queue->queue_lock, *flags); ++ if (*ptr == bfqd) ++ goto out; ++ spin_unlock_irqrestore(bfqd->queue->queue_lock, *flags); ++ } ++ ++ bfqd = NULL; ++out: ++ rcu_read_unlock(); ++ return bfqd; ++} ++ ++static inline void bfq_put_bfqd_unlock(struct bfq_data *bfqd, ++ unsigned long *flags) ++{ ++ spin_unlock_irqrestore(bfqd->queue->queue_lock, *flags); ++} ++ ++static void bfq_changed_ioprio(struct bfq_io_cq *bic); ++static void bfq_put_queue(struct bfq_queue *bfqq); ++static void bfq_dispatch_insert(struct request_queue *q, struct request *rq); ++static struct bfq_queue *bfq_get_queue(struct bfq_data *bfqd, ++ struct bfq_group *bfqg, int is_sync, ++ struct bfq_io_cq *bic, gfp_t gfp_mask); ++static void bfq_put_async_queues(struct bfq_data *bfqd, struct bfq_group *bfqg); ++static void bfq_exit_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq); ++#endif +-- +1.8.1.2 +