@@ -47,6 +47,13 @@ config IOSCHED_BFQ
processes according to their weights, regardless of the
device parameters and with any workload.
+config BFQ_GROUP_IOSCHED
+ bool "BFQ hierarchical scheduling support"
+ depends on IOSCHED_BFQ && BLK_CGROUP
+ default n
+ ---help---
+ Enable hierarchical scheduling in BFQ, using the blkio controller.
+
choice
prompt "Default I/O scheduler"
default DEFAULT_CFQ
@@ -34,9 +34,15 @@
* guarantee a low latency to non-I/O bound processes (the latter
* often belong to time-sensitive applications).
*
- * B-WF2Q+ is based on WF2Q+, which is described in [2], while the
- * augmented tree used here to implement B-WF2Q+ with O(log N)
- * complexity derives from the one introduced with EEVDF in [3].
+ * With respect to the version of BFQ presented in [1], and in the
+ * papers cited therein, this implementation adds a hierarchical
+ * extension based on H-WF2Q+. In this extension, also the service of
+ * whole groups of queues is scheduled using B-WF2Q+.
+ *
+ * B-WF2Q+ is based on WF2Q+, which is described in [2], together with
+ * H-WF2Q+, while the augmented tree used here to implement B-WF2Q+
+ * with O(log N) complexity derives from the one introduced with EEVDF
+ * in [3].
*
* [1] P. Valente, A. Avanzini, "Evolution of the BFQ Storage I/O
* Scheduler", Proceedings of the First Workshop on Mobile System
@@ -59,6 +65,7 @@
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/blkdev.h>
+#include <linux/cgroup.h>
#include <linux/elevator.h>
#include <linux/ktime.h>
#include <linux/rbtree.h>
@@ -78,7 +85,7 @@
#define BFQ_DEFAULT_QUEUE_IOPRIO 4
-#define BFQ_DEFAULT_GRP_WEIGHT 10
+#define BFQ_WEIGHT_LEGACY_DFL 100
#define BFQ_DEFAULT_GRP_IOPRIO 0
#define BFQ_DEFAULT_GRP_CLASS IOPRIO_CLASS_BE
@@ -110,10 +117,11 @@ struct bfq_service_tree {
* struct bfq_sched_data - multi-class scheduler.
*
* 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_in_service points to the active entity of the sched_data
- * service trees that will be scheduled next.
+ * ioprio_classes, and can be used either as a toplevel queue or as an
+ * intermediate queue on a hierarchical setup. @next_in_service
+ * points to the active entity of the sched_data service trees that
+ * will be scheduled next. It is used to reduce the number of steps
+ * needed for each hierarchical-schedule update.
*
* The supported ioprio_classes are the same as in CFQ, in descending
* priority order, IOPRIO_CLASS_RT, IOPRIO_CLASS_BE, IOPRIO_CLASS_IDLE.
@@ -124,7 +132,7 @@ struct bfq_service_tree {
*/
struct bfq_sched_data {
struct bfq_entity *in_service_entity; /* entity in service */
- /* head-of-the-line entity in the scheduler */
+ /* head-of-the-line entity in the scheduler (see comments above) */
struct bfq_entity *next_in_service;
/* array of service trees, one per ioprio_class */
struct bfq_service_tree service_tree[BFQ_IOPRIO_CLASSES];
@@ -133,10 +141,11 @@ struct bfq_sched_data {
/**
* struct bfq_entity - schedulable entity.
*
- * A bfq_entity is used to represent a bfq_queue (leaf node in the upper
- * level scheduler). Each entity belongs to the sched_data of the parent
- * group hierarchy. Non-leaf entities have also their own sched_data,
- * stored in @my_sched_data.
+ * 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
@@ -147,13 +156,14 @@ struct bfq_sched_data {
* update to take place the effective and the requested priority
* values are synchronized.
*
- * 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 hierarchy should be guaranteed. All the fields are
- * protected by the queue lock of the containing bfqd.
+ * 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; /* service_tree member */
@@ -203,11 +213,17 @@ struct bfq_entity {
int prio_changed;
};
+struct bfq_group;
+
/**
* struct bfq_queue - leaf schedulable entity.
*
* A bfq_queue is a leaf request queue; it can be associated with an
- * io_context or more, if it is async.
+ * io_context or more, if it is async. @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 destruction). All the fields
+ * are protected by the queue lock of the containing bfqd.
*/
struct bfq_queue {
/* reference counter */
@@ -290,6 +306,9 @@ struct bfq_io_cq {
struct bfq_ttime ttime;
/* per (request_queue, blkcg) ioprio */
int ioprio;
+#ifdef CONFIG_BFQ_GROUP_IOSCHED
+ uint64_t blkcg_serial_nr; /* the current blkcg serial */
+#endif
};
enum bfq_device_speed {
@@ -306,8 +325,8 @@ struct bfq_data {
/* request queue for the device */
struct request_queue *queue;
- /* root @bfq_sched_data for the device */
- struct bfq_sched_data sched_data;
+ /* root bfq_group for the device */
+ struct bfq_group *root_group;
/*
* Number of bfq_queues containing requests (including the
@@ -456,8 +475,35 @@ BFQ_BFQQ_FNS(IO_bound);
#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)
+#ifdef CONFIG_BFQ_GROUP_IOSCHED
+static struct bfq_group *bfqq_group(struct bfq_queue *bfqq);
+static struct blkcg_gq *bfqg_to_blkg(struct bfq_group *bfqg);
+
+#define bfq_log_bfqq(bfqd, bfqq, fmt, args...) do { \
+ char __pbuf[128]; \
+ \
+ blkg_path(bfqg_to_blkg(bfqq_group(bfqq)), __pbuf, sizeof(__pbuf)); \
+ blk_add_trace_msg((bfqd)->queue, "bfq%d%c %s " fmt, (bfqq)->pid, \
+ bfq_bfqq_sync((bfqq)) ? 'S' : 'A', \
+ __pbuf, ##args); \
+} while (0)
+
+#define bfq_log_bfqg(bfqd, bfqg, fmt, args...) do { \
+ char __pbuf[128]; \
+ \
+ blkg_path(bfqg_to_blkg(bfqg), __pbuf, sizeof(__pbuf)); \
+ blk_add_trace_msg((bfqd)->queue, "%s " fmt, __pbuf, ##args); \
+} while (0)
+
+#else /* CONFIG_BFQ_GROUP_IOSCHED */
+
+#define bfq_log_bfqq(bfqd, bfqq, fmt, args...) \
+ blk_add_trace_msg((bfqd)->queue, "bfq%d%c " fmt, (bfqq)->pid, \
+ bfq_bfqq_sync((bfqq)) ? 'S' : 'A', \
+ ##args)
+#define bfq_log_bfqg(bfqd, bfqg, fmt, args...) do {} while (0)
+
+#endif /* CONFIG_BFQ_GROUP_IOSCHED */
#define bfq_log(bfqd, fmt, args...) \
blk_add_trace_msg((bfqd)->queue, "bfq " fmt, ##args)
@@ -474,6 +520,107 @@ enum bfqq_expiration {
BFQ_BFQQ_PREEMPTED /* preemption in progress */
};
+struct bfqg_stats {
+#ifdef CONFIG_BFQ_GROUP_IOSCHED
+ /* number of ios merged */
+ struct blkg_rwstat merged;
+ /* total time spent on device in ns, may not be accurate w/ queueing */
+ struct blkg_rwstat service_time;
+ /* total time spent waiting in scheduler queue in ns */
+ struct blkg_rwstat wait_time;
+ /* number of IOs queued up */
+ struct blkg_rwstat queued;
+ /* total disk time and nr sectors dispatched by this group */
+ struct blkg_stat time;
+#ifdef CONFIG_DEBUG_BLK_CGROUP
+ /* sum of number of ios queued across all samples */
+ struct blkg_stat avg_queue_size_sum;
+ /* count of samples taken for average */
+ struct blkg_stat avg_queue_size_samples;
+ /* how many times this group has been removed from service tree */
+ struct blkg_stat dequeue;
+ /* total time spent waiting for it to be assigned a timeslice. */
+ struct blkg_stat group_wait_time;
+ /* time spent idling for this blkcg_gq */
+ struct blkg_stat idle_time;
+ /* total time with empty current active q with other requests queued */
+ struct blkg_stat empty_time;
+ /* fields after this shouldn't be cleared on stat reset */
+ uint64_t start_group_wait_time;
+ uint64_t start_idle_time;
+ uint64_t start_empty_time;
+ uint16_t flags;
+#endif /* CONFIG_DEBUG_BLK_CGROUP */
+#endif /* CONFIG_BFQ_GROUP_IOSCHED */
+};
+
+#ifdef CONFIG_BFQ_GROUP_IOSCHED
+
+/*
+ * struct bfq_group_data - per-blkcg storage for the blkio subsystem.
+ *
+ * @ps: @blkcg_policy_storage that this structure inherits
+ * @weight: weight of the bfq_group
+ */
+struct bfq_group_data {
+ /* must be the first member */
+ struct blkcg_policy_data pd;
+
+ unsigned short weight;
+};
+
+/**
+ * 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).
+ * @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.
+ * @stats: stats for this bfqg.
+ *
+ * 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 @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 {
+ /* must be the first member */
+ struct blkg_policy_data pd;
+
+ struct bfq_entity entity;
+ struct bfq_sched_data sched_data;
+
+ void *bfqd;
+
+ struct bfq_queue *async_bfqq[2][IOPRIO_BE_NR];
+ struct bfq_queue *async_idle_bfqq;
+
+ struct bfq_entity *my_entity;
+
+ struct bfqg_stats stats;
+};
+
+#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;
+
+ struct rb_root rq_pos_tree;
+};
+#endif
+
static struct bfq_queue *bfq_entity_to_bfqq(struct bfq_entity *entity);
static struct bfq_service_tree *
@@ -509,16 +656,9 @@ static void bfq_dispatch_insert(struct request_queue *q, struct request *rq);
static struct bfq_queue *bfq_get_queue(struct bfq_data *bfqd,
struct bio *bio, bool is_sync,
struct bfq_io_cq *bic);
+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);
-/*
- * Array of async queues for all the processes, one queue
- * per ioprio value per ioprio_class.
- */
-struct bfq_queue *async_bfqq[2][IOPRIO_BE_NR];
-/* Async queue for the idle class (ioprio is ignored) */
-struct bfq_queue *async_idle_bfqq;
-
/* Expiration time of sync (0) and async (1) requests, in ns. */
static const u64 bfq_fifo_expire[2] = { NSEC_PER_SEC / 4, NSEC_PER_SEC / 8 };
@@ -594,26 +734,81 @@ static struct bfq_io_cq *bfq_bic_lookup(struct bfq_data *bfqd,
return NULL;
}
+#ifdef CONFIG_BFQ_GROUP_IOSCHED
+
#define for_each_entity(entity) \
- for (; entity ; entity = NULL)
+ for (; entity ; entity = entity->parent)
#define for_each_entity_safe(entity, parent) \
- for (parent = NULL; entity ; 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 void bfq_update_budget(struct bfq_entity *next_in_service)
+{
+ struct bfq_entity *bfqg_entity;
+ struct bfq_group *bfqg;
+ struct bfq_sched_data *group_sd;
+
+ group_sd = next_in_service->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 in-service entity.
+ */
+ bfqg_entity = bfqg->my_entity;
+ if (bfqg_entity)
+ bfqg_entity->budget = next_in_service->budget;
+}
static int bfq_update_next_in_service(struct bfq_sched_data *sd)
{
- return 0;
+ struct bfq_entity *next_in_service;
+
+ if (sd->in_service_entity)
+ /* 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_in_service = bfq_lookup_next_entity(sd, 0, NULL);
+ sd->next_in_service = next_in_service;
+
+ if (next_in_service)
+ bfq_update_budget(next_in_service);
+
+ return 1;
}
-static void bfq_check_next_in_service(struct bfq_sched_data *sd,
- struct bfq_entity *entity)
+#else /* CONFIG_BFQ_GROUP_IOSCHED */
+
+#define for_each_entity(entity) \
+ for (; entity ; entity = NULL)
+
+#define for_each_entity_safe(entity, parent) \
+ for (parent = NULL; entity ; entity = parent)
+
+static int bfq_update_next_in_service(struct bfq_sched_data *sd)
{
+ return 0;
}
static void bfq_update_budget(struct bfq_entity *next_in_service)
{
}
+#endif /* CONFIG_BFQ_GROUP_IOSCHED */
+
/*
* Shift for timestamp calculations. This actually limits the maximum
* service allowed in one timestamp delta (small shift values increase it),
@@ -853,6 +1048,11 @@ static void bfq_active_insert(struct bfq_service_tree *st,
{
struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity);
struct rb_node *node = &entity->rb_node;
+#ifdef CONFIG_BFQ_GROUP_IOSCHED
+ struct bfq_sched_data *sd = NULL;
+ struct bfq_group *bfqg = NULL;
+ struct bfq_data *bfqd = NULL;
+#endif
bfq_insert(&st->active, entity);
@@ -863,6 +1063,11 @@ static void bfq_active_insert(struct bfq_service_tree *st,
bfq_update_active_tree(node);
+#ifdef CONFIG_BFQ_GROUP_IOSCHED
+ sd = entity->sched_data;
+ bfqg = container_of(sd, struct bfq_group, sched_data);
+ bfqd = (struct bfq_data *)bfqg->bfqd;
+#endif
if (bfqq)
list_add(&bfqq->bfqq_list, &bfqq->bfqd->active_list);
}
@@ -941,6 +1146,11 @@ static void bfq_active_extract(struct bfq_service_tree *st,
{
struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity);
struct rb_node *node;
+#ifdef CONFIG_BFQ_GROUP_IOSCHED
+ struct bfq_sched_data *sd = NULL;
+ struct bfq_group *bfqg = NULL;
+ struct bfq_data *bfqd = NULL;
+#endif
node = bfq_find_deepest(&entity->rb_node);
bfq_extract(&st->active, entity);
@@ -948,6 +1158,11 @@ static void bfq_active_extract(struct bfq_service_tree *st,
if (node)
bfq_update_active_tree(node);
+#ifdef CONFIG_BFQ_GROUP_IOSCHED
+ sd = entity->sched_data;
+ bfqg = container_of(sd, struct bfq_group, sched_data);
+ bfqd = (struct bfq_data *)bfqg->bfqd;
+#endif
if (bfqq)
list_del(&bfqq->bfqq_list);
}
@@ -1039,7 +1254,7 @@ static void bfq_forget_idle(struct bfq_service_tree *st)
static struct bfq_service_tree *
__bfq_entity_update_weight_prio(struct bfq_service_tree *old_st,
- struct bfq_entity *entity)
+ struct bfq_entity *entity)
{
struct bfq_service_tree *new_st = old_st;
@@ -1047,9 +1262,20 @@ __bfq_entity_update_weight_prio(struct bfq_service_tree *old_st,
struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity);
unsigned short prev_weight, new_weight;
struct bfq_data *bfqd = NULL;
+#ifdef CONFIG_BFQ_GROUP_IOSCHED
+ struct bfq_sched_data *sd;
+ struct bfq_group *bfqg;
+#endif
if (bfqq)
bfqd = bfqq->bfqd;
+#ifdef CONFIG_BFQ_GROUP_IOSCHED
+ else {
+ sd = entity->my_sched_data;
+ bfqg = container_of(sd, struct bfq_group, sched_data);
+ bfqd = (struct bfq_data *)bfqg->bfqd;
+ }
+#endif
old_st->wsum -= entity->weight;
@@ -1095,6 +1321,9 @@ __bfq_entity_update_weight_prio(struct bfq_service_tree *old_st,
return new_st;
}
+static void bfqg_stats_set_start_empty_time(struct bfq_group *bfqg);
+static struct bfq_group *bfqq_group(struct bfq_queue *bfqq);
+
/**
* bfq_bfqq_served - update the scheduler status after selection for
* service.
@@ -1118,6 +1347,7 @@ static void bfq_bfqq_served(struct bfq_queue *bfqq, int served)
st->vtime += bfq_delta(served, st->wsum);
bfq_forget_idle(st);
}
+ bfqg_stats_set_start_empty_time(bfqq_group(bfqq));
bfq_log_bfqq(bfqq->bfqd, bfqq, "bfqq_served %d secs", served);
}
@@ -1289,13 +1519,16 @@ static void bfq_activate_entity(struct bfq_entity *entity,
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_in_service = entity == sd->in_service_entity;
+ struct bfq_service_tree *st;
+ int was_in_service;
int ret = 0;
- if (!entity->on_st)
+ if (sd == NULL || !entity->on_st) /* never activated, or inactive now */
return 0;
+ st = bfq_entity_service_tree(entity);
+ was_in_service = entity == sd->in_service_entity;
+
if (was_in_service) {
bfq_calc_finish(entity, entity->service);
sd->in_service_entity = NULL;
@@ -1330,17 +1563,18 @@ static void bfq_deactivate_entity(struct bfq_entity *entity, int requeue)
if (!__bfq_deactivate_entity(entity, requeue))
/*
- * The parent entity is still backlogged, and
- * we don't need to update it as it is still
- * in service.
+ * next_in_service has not been changed, so
+ * no upwards update is needed
*/
break;
if (sd->next_in_service)
/*
- * The parent entity is still backlogged and
- * the budgets on the path towards the root
- * need to be updated.
+ * The parent entity is still backlogged,
+ * because next_in_service is not NULL, and
+ * next_in_service has been updated (see
+ * comment on the body of the above if):
+ * upwards update of the schedule is needed.
*/
goto update;
@@ -1434,8 +1668,8 @@ static struct bfq_entity *bfq_first_active_entity(struct bfq_service_tree *st)
* 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)
+static struct bfq_entity *
+__bfq_lookup_next_entity(struct bfq_service_tree *st, bool force)
{
struct bfq_entity *entity, *new_next_in_service = NULL;
@@ -1456,161 +1690,1283 @@ static struct bfq_entity *__bfq_lookup_next_entity(struct bfq_service_tree *st,
bfq_update_budget(new_next_in_service);
}
- return entity;
+ 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_in_service entity at each level of the
+ * hierarchy, the complexity of the lookup can be decreased with
+ * absolutely no effort just returning the cached next_in_service 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;
+
+ /*
+ * Choose from idle class, if needed to guarantee a minimum
+ * bandwidth to this class. This should also mitigate
+ * priority-inversion problems in case a low priority task is
+ * holding file system resources.
+ */
+ if (bfqd &&
+ jiffies - bfqd->bfq_class_idle_last_service >
+ BFQ_CL_IDLE_TIMEOUT) {
+ entity = __bfq_lookup_next_entity(st + BFQ_IOPRIO_CLASSES - 1,
+ true);
+ if (entity) {
+ i = BFQ_IOPRIO_CLASSES - 1;
+ bfqd->bfq_class_idle_last_service = jiffies;
+ sd->next_in_service = entity;
+ }
+ }
+ for (; i < BFQ_IOPRIO_CLASSES; i++) {
+ entity = __bfq_lookup_next_entity(st + i, false);
+ if (entity) {
+ if (extract) {
+ bfq_active_extract(st + i, entity);
+ sd->in_service_entity = entity;
+ sd->next_in_service = NULL;
+ }
+ break;
+ }
+ }
+
+ return entity;
+}
+
+static bool next_queue_may_preempt(struct bfq_data *bfqd)
+{
+ struct bfq_sched_data *sd = &bfqd->root_group->sched_data;
+
+ return sd->next_in_service != sd->in_service_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;
+
+ if (bfqd->busy_queues == 0)
+ return NULL;
+
+ sd = &bfqd->root_group->sched_data;
+ for (; sd ; sd = entity->my_sched_data) {
+ entity = bfq_lookup_next_entity(sd, 1, bfqd);
+ entity->service = 0;
+ }
+
+ bfqq = bfq_entity_to_bfqq(entity);
+
+ return bfqq;
+}
+
+static void __bfq_bfqd_reset_in_service(struct bfq_data *bfqd)
+{
+ if (bfqd->in_service_bic) {
+ put_io_context(bfqd->in_service_bic->icq.ioc);
+ bfqd->in_service_bic = NULL;
+ }
+
+ bfq_clear_bfqq_wait_request(bfqd->in_service_queue);
+ hrtimer_try_to_cancel(&bfqd->idle_slice_timer);
+ bfqd->in_service_queue = NULL;
+}
+
+static void bfq_deactivate_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq,
+ int requeue)
+{
+ struct bfq_entity *entity = &bfqq->entity;
+
+ 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, bfq_bfqq_non_blocking_wait_rq(bfqq));
+ bfq_clear_bfqq_non_blocking_wait_rq(bfqq);
+}
+
+static void bfqg_stats_update_dequeue(struct bfq_group *bfqg);
+
+/*
+ * 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)
+{
+ bfq_log_bfqq(bfqd, bfqq, "del from busy");
+
+ bfq_clear_bfqq_busy(bfqq);
+
+ bfqd->busy_queues--;
+
+ bfqg_stats_update_dequeue(bfqq_group(bfqq));
+
+ 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)
+{
+ bfq_log_bfqq(bfqd, bfqq, "add to busy");
+
+ bfq_activate_bfqq(bfqd, bfqq);
+
+ bfq_mark_bfqq_busy(bfqq);
+ bfqd->busy_queues++;
+}
+
+#if defined(CONFIG_BFQ_GROUP_IOSCHED) && defined(CONFIG_DEBUG_BLK_CGROUP)
+
+/* bfqg stats flags */
+enum bfqg_stats_flags {
+ BFQG_stats_waiting = 0,
+ BFQG_stats_idling,
+ BFQG_stats_empty,
+};
+
+#define BFQG_FLAG_FNS(name) \
+static void bfqg_stats_mark_##name(struct bfqg_stats *stats) \
+{ \
+ stats->flags |= (1 << BFQG_stats_##name); \
+} \
+static void bfqg_stats_clear_##name(struct bfqg_stats *stats) \
+{ \
+ stats->flags &= ~(1 << BFQG_stats_##name); \
+} \
+static int bfqg_stats_##name(struct bfqg_stats *stats) \
+{ \
+ return (stats->flags & (1 << BFQG_stats_##name)) != 0; \
+} \
+
+BFQG_FLAG_FNS(waiting)
+BFQG_FLAG_FNS(idling)
+BFQG_FLAG_FNS(empty)
+#undef BFQG_FLAG_FNS
+
+/* This should be called with the queue_lock held. */
+static void bfqg_stats_update_group_wait_time(struct bfqg_stats *stats)
+{
+ unsigned long long now;
+
+ if (!bfqg_stats_waiting(stats))
+ return;
+
+ now = sched_clock();
+ if (time_after64(now, stats->start_group_wait_time))
+ blkg_stat_add(&stats->group_wait_time,
+ now - stats->start_group_wait_time);
+ bfqg_stats_clear_waiting(stats);
+}
+
+/* This should be called with the queue_lock held. */
+static void bfqg_stats_set_start_group_wait_time(struct bfq_group *bfqg,
+ struct bfq_group *curr_bfqg)
+{
+ struct bfqg_stats *stats = &bfqg->stats;
+
+ if (bfqg_stats_waiting(stats))
+ return;
+ if (bfqg == curr_bfqg)
+ return;
+ stats->start_group_wait_time = sched_clock();
+ bfqg_stats_mark_waiting(stats);
+}
+
+/* This should be called with the queue_lock held. */
+static void bfqg_stats_end_empty_time(struct bfqg_stats *stats)
+{
+ unsigned long long now;
+
+ if (!bfqg_stats_empty(stats))
+ return;
+
+ now = sched_clock();
+ if (time_after64(now, stats->start_empty_time))
+ blkg_stat_add(&stats->empty_time,
+ now - stats->start_empty_time);
+ bfqg_stats_clear_empty(stats);
+}
+
+static void bfqg_stats_update_dequeue(struct bfq_group *bfqg)
+{
+ blkg_stat_add(&bfqg->stats.dequeue, 1);
+}
+
+static void bfqg_stats_set_start_empty_time(struct bfq_group *bfqg)
+{
+ struct bfqg_stats *stats = &bfqg->stats;
+
+ if (blkg_rwstat_total(&stats->queued))
+ return;
+
+ /*
+ * group is already marked empty. This can happen if bfqq got new
+ * request in parent group and moved to this group while being added
+ * to service tree. Just ignore the event and move on.
+ */
+ if (bfqg_stats_empty(stats))
+ return;
+
+ stats->start_empty_time = sched_clock();
+ bfqg_stats_mark_empty(stats);
+}
+
+static void bfqg_stats_update_idle_time(struct bfq_group *bfqg)
+{
+ struct bfqg_stats *stats = &bfqg->stats;
+
+ if (bfqg_stats_idling(stats)) {
+ unsigned long long now = sched_clock();
+
+ if (time_after64(now, stats->start_idle_time))
+ blkg_stat_add(&stats->idle_time,
+ now - stats->start_idle_time);
+ bfqg_stats_clear_idling(stats);
+ }
+}
+
+static void bfqg_stats_set_start_idle_time(struct bfq_group *bfqg)
+{
+ struct bfqg_stats *stats = &bfqg->stats;
+
+ stats->start_idle_time = sched_clock();
+ bfqg_stats_mark_idling(stats);
+}
+
+static void bfqg_stats_update_avg_queue_size(struct bfq_group *bfqg)
+{
+ struct bfqg_stats *stats = &bfqg->stats;
+
+ blkg_stat_add(&stats->avg_queue_size_sum,
+ blkg_rwstat_total(&stats->queued));
+ blkg_stat_add(&stats->avg_queue_size_samples, 1);
+ bfqg_stats_update_group_wait_time(stats);
+}
+
+#else /* CONFIG_BFQ_GROUP_IOSCHED && CONFIG_DEBUG_BLK_CGROUP */
+
+static inline void
+bfqg_stats_set_start_group_wait_time(struct bfq_group *bfqg,
+ struct bfq_group *curr_bfqg) { }
+static inline void bfqg_stats_end_empty_time(struct bfqg_stats *stats) { }
+static inline void bfqg_stats_update_dequeue(struct bfq_group *bfqg) { }
+static inline void bfqg_stats_set_start_empty_time(struct bfq_group *bfqg) { }
+static inline void bfqg_stats_update_idle_time(struct bfq_group *bfqg) { }
+static inline void bfqg_stats_set_start_idle_time(struct bfq_group *bfqg) { }
+static inline void bfqg_stats_update_avg_queue_size(struct bfq_group *bfqg) { }
+
+#endif /* CONFIG_BFQ_GROUP_IOSCHED && CONFIG_DEBUG_BLK_CGROUP */
+
+#ifdef CONFIG_BFQ_GROUP_IOSCHED
+
+/*
+ * blk-cgroup policy-related handlers
+ * The following functions help in converting between blk-cgroup
+ * internal structures and BFQ-specific structures.
+ */
+
+static struct bfq_group *pd_to_bfqg(struct blkg_policy_data *pd)
+{
+ return pd ? container_of(pd, struct bfq_group, pd) : NULL;
+}
+
+static struct blkcg_gq *bfqg_to_blkg(struct bfq_group *bfqg)
+{
+ return pd_to_blkg(&bfqg->pd);
+}
+
+static struct blkcg_policy blkcg_policy_bfq;
+
+static struct bfq_group *blkg_to_bfqg(struct blkcg_gq *blkg)
+{
+ return pd_to_bfqg(blkg_to_pd(blkg, &blkcg_policy_bfq));
+}
+
+/*
+ * bfq_group handlers
+ * The following functions help in navigating the bfq_group hierarchy
+ * by allowing to find the parent of a bfq_group or the bfq_group
+ * associated to a bfq_queue.
+ */
+
+static struct bfq_group *bfqg_parent(struct bfq_group *bfqg)
+{
+ struct blkcg_gq *pblkg = bfqg_to_blkg(bfqg)->parent;
+
+ return pblkg ? blkg_to_bfqg(pblkg) : NULL;
+}
+
+static struct bfq_group *bfqq_group(struct bfq_queue *bfqq)
+{
+ struct bfq_entity *group_entity = bfqq->entity.parent;
+
+ return group_entity ? container_of(group_entity, struct bfq_group,
+ entity) :
+ bfqq->bfqd->root_group;
+}
+
+/*
+ * The following two functions handle get and put of a bfq_group by
+ * wrapping the related blk-cgroup hooks.
+ */
+
+static void bfqg_get(struct bfq_group *bfqg)
+{
+ return blkg_get(bfqg_to_blkg(bfqg));
+}
+
+static void bfqg_put(struct bfq_group *bfqg)
+{
+ return blkg_put(bfqg_to_blkg(bfqg));
+}
+
+static void bfqg_stats_update_io_add(struct bfq_group *bfqg,
+ struct bfq_queue *bfqq,
+ int op, int op_flags)
+{
+ blkg_rwstat_add(&bfqg->stats.queued, op, op_flags, 1);
+ bfqg_stats_end_empty_time(&bfqg->stats);
+ if (!(bfqq == ((struct bfq_data *)bfqg->bfqd)->in_service_queue))
+ bfqg_stats_set_start_group_wait_time(bfqg, bfqq_group(bfqq));
+}
+
+static void bfqg_stats_update_io_remove(struct bfq_group *bfqg, int op,
+ int op_flags)
+{
+ blkg_rwstat_add(&bfqg->stats.queued, op, op_flags, -1);
+}
+
+static void bfqg_stats_update_io_merged(struct bfq_group *bfqg, int op,
+ int op_flags)
+{
+ blkg_rwstat_add(&bfqg->stats.merged, op, op_flags, 1);
+}
+
+static void bfqg_stats_update_completion(struct bfq_group *bfqg,
+ uint64_t start_time, uint64_t io_start_time, int op,
+ int op_flags)
+{
+ struct bfqg_stats *stats = &bfqg->stats;
+ unsigned long long now = sched_clock();
+
+ if (time_after64(now, io_start_time))
+ blkg_rwstat_add(&stats->service_time, op, op_flags,
+ now - io_start_time);
+ if (time_after64(io_start_time, start_time))
+ blkg_rwstat_add(&stats->wait_time, op, op_flags,
+ io_start_time - start_time);
+}
+
+/* @stats = 0 */
+static void bfqg_stats_reset(struct bfqg_stats *stats)
+{
+ /* queued stats shouldn't be cleared */
+ blkg_rwstat_reset(&stats->merged);
+ blkg_rwstat_reset(&stats->service_time);
+ blkg_rwstat_reset(&stats->wait_time);
+ blkg_stat_reset(&stats->time);
+#ifdef CONFIG_DEBUG_BLK_CGROUP
+ blkg_stat_reset(&stats->avg_queue_size_sum);
+ blkg_stat_reset(&stats->avg_queue_size_samples);
+ blkg_stat_reset(&stats->dequeue);
+ blkg_stat_reset(&stats->group_wait_time);
+ blkg_stat_reset(&stats->idle_time);
+ blkg_stat_reset(&stats->empty_time);
+#endif
+}
+
+/* @to += @from */
+static void bfqg_stats_add_aux(struct bfqg_stats *to, struct bfqg_stats *from)
+{
+ if (!to || !from)
+ return;
+
+ /* queued stats shouldn't be cleared */
+ blkg_rwstat_add_aux(&to->merged, &from->merged);
+ blkg_rwstat_add_aux(&to->service_time, &from->service_time);
+ blkg_rwstat_add_aux(&to->wait_time, &from->wait_time);
+ blkg_stat_add_aux(&from->time, &from->time);
+#ifdef CONFIG_DEBUG_BLK_CGROUP
+ blkg_stat_add_aux(&to->avg_queue_size_sum, &from->avg_queue_size_sum);
+ blkg_stat_add_aux(&to->avg_queue_size_samples,
+ &from->avg_queue_size_samples);
+ blkg_stat_add_aux(&to->dequeue, &from->dequeue);
+ blkg_stat_add_aux(&to->group_wait_time, &from->group_wait_time);
+ blkg_stat_add_aux(&to->idle_time, &from->idle_time);
+ blkg_stat_add_aux(&to->empty_time, &from->empty_time);
+#endif
+}
+
+/*
+ * Transfer @bfqg's stats to its parent's aux counts so that the ancestors'
+ * recursive stats can still account for the amount used by this bfqg after
+ * it's gone.
+ */
+static void bfqg_stats_xfer_dead(struct bfq_group *bfqg)
+{
+ struct bfq_group *parent;
+
+ if (!bfqg) /* root_group */
+ return;
+
+ parent = bfqg_parent(bfqg);
+
+ lockdep_assert_held(bfqg_to_blkg(bfqg)->q->queue_lock);
+
+ if (unlikely(!parent))
+ return;
+
+ bfqg_stats_add_aux(&parent->stats, &bfqg->stats);
+ bfqg_stats_reset(&bfqg->stats);
+}
+
+static void bfq_init_entity(struct bfq_entity *entity,
+ struct bfq_group *bfqg)
+{
+ struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity);
+
+ entity->weight = entity->new_weight;
+ entity->orig_weight = entity->new_weight;
+ if (bfqq) {
+ bfqq->ioprio = bfqq->new_ioprio;
+ bfqq->ioprio_class = bfqq->new_ioprio_class;
+ bfqg_get(bfqg);
+ }
+ entity->parent = bfqg->my_entity;
+ entity->sched_data = &bfqg->sched_data;
+}
+
+static void bfqg_stats_exit(struct bfqg_stats *stats)
+{
+ blkg_rwstat_exit(&stats->merged);
+ blkg_rwstat_exit(&stats->service_time);
+ blkg_rwstat_exit(&stats->wait_time);
+ blkg_rwstat_exit(&stats->queued);
+ blkg_stat_exit(&stats->time);
+#ifdef CONFIG_DEBUG_BLK_CGROUP
+ blkg_stat_exit(&stats->avg_queue_size_sum);
+ blkg_stat_exit(&stats->avg_queue_size_samples);
+ blkg_stat_exit(&stats->dequeue);
+ blkg_stat_exit(&stats->group_wait_time);
+ blkg_stat_exit(&stats->idle_time);
+ blkg_stat_exit(&stats->empty_time);
+#endif
+}
+
+static int bfqg_stats_init(struct bfqg_stats *stats, gfp_t gfp)
+{
+ if (blkg_rwstat_init(&stats->merged, gfp) ||
+ blkg_rwstat_init(&stats->service_time, gfp) ||
+ blkg_rwstat_init(&stats->wait_time, gfp) ||
+ blkg_rwstat_init(&stats->queued, gfp) ||
+ blkg_stat_init(&stats->time, gfp))
+ goto err;
+
+#ifdef CONFIG_DEBUG_BLK_CGROUP
+ if (blkg_stat_init(&stats->avg_queue_size_sum, gfp) ||
+ blkg_stat_init(&stats->avg_queue_size_samples, gfp) ||
+ blkg_stat_init(&stats->dequeue, gfp) ||
+ blkg_stat_init(&stats->group_wait_time, gfp) ||
+ blkg_stat_init(&stats->idle_time, gfp) ||
+ blkg_stat_init(&stats->empty_time, gfp))
+ goto err;
+#endif
+ return 0;
+err:
+ bfqg_stats_exit(stats);
+ return -ENOMEM;
+}
+
+static struct bfq_group_data *cpd_to_bfqgd(struct blkcg_policy_data *cpd)
+{
+ return cpd ? container_of(cpd, struct bfq_group_data, pd) : NULL;
+}
+
+static struct bfq_group_data *blkcg_to_bfqgd(struct blkcg *blkcg)
+{
+ return cpd_to_bfqgd(blkcg_to_cpd(blkcg, &blkcg_policy_bfq));
+}
+
+static struct blkcg_policy_data *bfq_cpd_alloc(gfp_t gfp)
+{
+ struct bfq_group_data *bgd;
+
+ bgd = kzalloc(sizeof(*bgd), GFP_KERNEL);
+ if (!bgd)
+ return NULL;
+ return &bgd->pd;
+}
+
+static void bfq_cpd_init(struct blkcg_policy_data *cpd)
+{
+ struct bfq_group_data *d = cpd_to_bfqgd(cpd);
+
+ d->weight = cgroup_subsys_on_dfl(io_cgrp_subsys) ?
+ CGROUP_WEIGHT_DFL : BFQ_WEIGHT_LEGACY_DFL;
+}
+
+static void bfq_cpd_free(struct blkcg_policy_data *cpd)
+{
+ kfree(cpd_to_bfqgd(cpd));
+}
+
+static struct blkg_policy_data *bfq_pd_alloc(gfp_t gfp, int node)
+{
+ struct bfq_group *bfqg;
+
+ bfqg = kzalloc_node(sizeof(*bfqg), gfp, node);
+ if (!bfqg)
+ return NULL;
+
+ if (bfqg_stats_init(&bfqg->stats, gfp)) {
+ kfree(bfqg);
+ return NULL;
+ }
+
+ return &bfqg->pd;
+}
+
+static void bfq_pd_init(struct blkg_policy_data *pd)
+{
+ struct blkcg_gq *blkg = pd_to_blkg(pd);
+ struct bfq_group *bfqg = blkg_to_bfqg(blkg);
+ struct bfq_data *bfqd = blkg->q->elevator->elevator_data;
+ struct bfq_entity *entity = &bfqg->entity;
+ struct bfq_group_data *d = blkcg_to_bfqgd(blkg->blkcg);
+
+ entity->orig_weight = entity->weight = entity->new_weight = d->weight;
+ entity->my_sched_data = &bfqg->sched_data;
+ bfqg->my_entity = entity; /*
+ * the root_group's will be set to NULL
+ * in bfq_init_queue()
+ */
+ bfqg->bfqd = bfqd;
+}
+
+static void bfq_pd_free(struct blkg_policy_data *pd)
+{
+ struct bfq_group *bfqg = pd_to_bfqg(pd);
+
+ bfqg_stats_exit(&bfqg->stats);
+ return kfree(bfqg);
+}
+
+static void bfq_pd_reset_stats(struct blkg_policy_data *pd)
+{
+ struct bfq_group *bfqg = pd_to_bfqg(pd);
+
+ bfqg_stats_reset(&bfqg->stats);
+}
+
+static void bfq_group_set_parent(struct bfq_group *bfqg,
+ struct bfq_group *parent)
+{
+ struct bfq_entity *entity;
+
+ entity = &bfqg->entity;
+ entity->parent = parent->my_entity;
+ entity->sched_data = &parent->sched_data;
+}
+
+static struct bfq_group *bfq_lookup_bfqg(struct bfq_data *bfqd,
+ struct blkcg *blkcg)
+{
+ struct blkcg_gq *blkg;
+
+ blkg = blkg_lookup(blkcg, bfqd->queue);
+ if (likely(blkg))
+ return blkg_to_bfqg(blkg);
+ return NULL;
+}
+
+static struct bfq_group *bfq_find_set_group(struct bfq_data *bfqd,
+ struct blkcg *blkcg)
+{
+ struct bfq_group *bfqg, *parent;
+ struct bfq_entity *entity;
+
+ assert_spin_locked(bfqd->queue->queue_lock);
+
+ bfqg = bfq_lookup_bfqg(bfqd, blkcg);
+
+ if (unlikely(!bfqg))
+ return NULL;
+
+ /*
+ * Update chain of bfq_groups as we might be handling a leaf group
+ * which, along with some of its relatives, has not been hooked yet
+ * to the private hierarchy of BFQ.
+ */
+ entity = &bfqg->entity;
+ for_each_entity(entity) {
+ bfqg = container_of(entity, struct bfq_group, entity);
+ if (bfqg != bfqd->root_group) {
+ parent = bfqg_parent(bfqg);
+ if (!parent)
+ parent = bfqd->root_group;
+ bfq_group_set_parent(bfqg, parent);
+ }
+ }
+
+ return bfqg;
+}
+
+static void bfq_bfqq_expire(struct bfq_data *bfqd,
+ struct bfq_queue *bfqq,
+ bool compensate,
+ enum bfqq_expiration reason);
+
+
+/**
+ * bfq_bfqq_move - migrate @bfqq to @bfqg.
+ * @bfqd: queue descriptor.
+ * @bfqq: the queue to move.
+ * @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_group *bfqg)
+{
+ struct bfq_entity *entity = &bfqq->entity;
+
+ /* If bfqq is empty, then bfq_bfqq_expire also invokes
+ * bfq_del_bfqq_busy, thereby removing bfqq and its entity
+ * from data structures related to current group. Otherwise we
+ * need to remove bfqq explicitly with bfq_deactivate_bfqq, as
+ * we do below.
+ */
+ if (bfqq == bfqd->in_service_queue)
+ bfq_bfqq_expire(bfqd, bfqd->in_service_queue,
+ false, BFQ_BFQQ_PREEMPTED);
+
+ if (bfq_bfqq_busy(bfqq))
+ bfq_deactivate_bfqq(bfqd, bfqq, 0);
+ else if (entity->on_st)
+ bfq_put_idle_entity(bfq_entity_service_tree(entity), entity);
+ bfqg_put(bfqq_group(bfqq));
+
+ /*
+ * 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;
+ bfqg_get(bfqg);
+
+ if (bfq_bfqq_busy(bfqq))
+ bfq_activate_bfqq(bfqd, bfqq);
+
+ if (!bfqd->in_service_queue && !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.
+ * @blkcg: the blk-cgroup to move to.
+ *
+ * Move bic to blkcg, 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 blkcg *blkcg)
+{
+ struct bfq_queue *async_bfqq = bic_to_bfqq(bic, 0);
+ struct bfq_queue *sync_bfqq = bic_to_bfqq(bic, 1);
+ struct bfq_group *bfqg;
+ struct bfq_entity *entity;
+
+ lockdep_assert_held(bfqd->queue->queue_lock);
+
+ bfqg = bfq_find_set_group(bfqd, blkcg);
+
+ if (unlikely(!bfqg))
+ bfqg = bfqd->root_group;
+
+ if (async_bfqq) {
+ 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,
+ async_bfqq->ref);
+ bfq_put_queue(async_bfqq);
+ }
+ }
+
+ if (sync_bfqq) {
+ entity = &sync_bfqq->entity;
+ if (entity->sched_data != &bfqg->sched_data)
+ bfq_bfqq_move(bfqd, sync_bfqq, bfqg);
+ }
+
+ return bfqg;
+}
+
+static void bfq_bic_update_cgroup(struct bfq_io_cq *bic, struct bio *bio)
+{
+ struct bfq_data *bfqd = bic_to_bfqd(bic);
+ struct bfq_group *bfqg = NULL;
+ uint64_t serial_nr;
+
+ rcu_read_lock();
+ serial_nr = bio_blkcg(bio)->css.serial_nr;
+
+ /*
+ * Check whether blkcg has changed. The condition may trigger
+ * spuriously on a newly created cic but there's no harm.
+ */
+ if (unlikely(!bfqd) || likely(bic->blkcg_serial_nr == serial_nr))
+ goto out;
+
+ bfqg = __bfq_bic_change_cgroup(bfqd, bic, bio_blkcg(bio));
+ bic->blkcg_serial_nr = serial_nr;
+out:
+ rcu_read_unlock();
+}
+
+/**
+ * bfq_flush_idle_tree - deactivate any entity on the idle tree of @st.
+ * @st: the service tree being flushed.
+ */
+static void bfq_flush_idle_tree(struct bfq_service_tree *st)
+{
+ struct bfq_entity *entity = st->first_idle;
+
+ for (; entity ; 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 void bfq_reparent_leaf_entity(struct bfq_data *bfqd,
+ struct bfq_entity *entity)
+{
+ struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity);
+
+ bfq_bfqq_move(bfqd, bfqq, bfqd->root_group);
+}
+
+/**
+ * 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 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 ; entity = bfq_entity_of(rb_first(active)))
+ bfq_reparent_leaf_entity(bfqd, entity);
+
+ if (bfqg->sched_data.in_service_entity)
+ bfq_reparent_leaf_entity(bfqd,
+ bfqg->sched_data.in_service_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.
+ * bfq_pd_offline - deactivate the entity associated with @pd,
+ * and reparent its children entities.
+ * @pd: descriptor of the policy going offline.
*
- * NOTE: since we cache the next_in_service entity at each level of the
- * hierarchy, the complexity of the lookup can be decreased with
- * absolutely no effort just returning the cached next_in_service value;
- * we prefer to do full lookups to test the consistency of the data
- * structures.
+ * blkio already grabs the queue_lock for us, so no need to use
+ * RCU-based magic
*/
-static struct bfq_entity *bfq_lookup_next_entity(struct bfq_sched_data *sd,
- int extract,
- struct bfq_data *bfqd)
+static void bfq_pd_offline(struct blkg_policy_data *pd)
{
- struct bfq_service_tree *st = sd->service_tree;
- struct bfq_entity *entity;
- int i = 0;
+ struct bfq_service_tree *st;
+ struct bfq_group *bfqg = pd_to_bfqg(pd);
+ struct bfq_data *bfqd = bfqg->bfqd;
+ struct bfq_entity *entity = bfqg->my_entity;
+ int i;
+
+ if (!entity) /* root group */
+ return;
/*
- * Choose from idle class, if needed to guarantee a minimum
- * bandwidth to this class. This should also mitigate
- * priority-inversion problems in case a low priority task is
- * holding file system resources.
+ * Empty all service_trees belonging to this group before
+ * deactivating the group itself.
*/
- if (bfqd &&
- jiffies - bfqd->bfq_class_idle_last_service >
- BFQ_CL_IDLE_TIMEOUT) {
- entity = __bfq_lookup_next_entity(st + BFQ_IOPRIO_CLASSES - 1,
- true);
- if (entity) {
- i = BFQ_IOPRIO_CLASSES - 1;
- bfqd->bfq_class_idle_last_service = jiffies;
- sd->next_in_service = entity;
- }
+ 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. No one 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
+ * in 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.
+ */
+ bfq_reparent_active_entities(bfqd, bfqg, st);
}
- for (; i < BFQ_IOPRIO_CLASSES; i++) {
- entity = __bfq_lookup_next_entity(st + i, false);
- if (entity) {
- if (extract) {
- bfq_check_next_in_service(sd, entity);
- bfq_active_extract(st + i, entity);
- sd->in_service_entity = entity;
- sd->next_in_service = NULL;
- }
- break;
+
+ __bfq_deactivate_entity(entity, 0);
+ bfq_put_async_queues(bfqd, bfqg);
+
+ /*
+ * @blkg is going offline and will be ignored by
+ * blkg_[rw]stat_recursive_sum(). Transfer stats to the parent so
+ * that they don't get lost. If IOs complete after this point, the
+ * stats for them will be lost. Oh well...
+ */
+ bfqg_stats_xfer_dead(bfqg);
+}
+
+static int bfq_io_show_weight(struct seq_file *sf, void *v)
+{
+ struct blkcg *blkcg = css_to_blkcg(seq_css(sf));
+ struct bfq_group_data *bfqgd = blkcg_to_bfqgd(blkcg);
+ unsigned int val = 0;
+
+ if (bfqgd)
+ val = bfqgd->weight;
+
+ seq_printf(sf, "%u\n", val);
+
+ return 0;
+}
+
+static int bfq_io_set_weight_legacy(struct cgroup_subsys_state *css,
+ struct cftype *cftype,
+ u64 val)
+{
+ struct blkcg *blkcg = css_to_blkcg(css);
+ struct bfq_group_data *bfqgd = blkcg_to_bfqgd(blkcg);
+ struct blkcg_gq *blkg;
+ int ret = -ERANGE;
+
+ if (val < BFQ_MIN_WEIGHT || val > BFQ_MAX_WEIGHT)
+ return ret;
+
+ ret = 0;
+ spin_lock_irq(&blkcg->lock);
+ bfqgd->weight = (unsigned short)val;
+ hlist_for_each_entry(blkg, &blkcg->blkg_list, blkcg_node) {
+ struct bfq_group *bfqg = blkg_to_bfqg(blkg);
+
+ if (!bfqg)
+ continue;
+ /*
+ * Setting the prio_changed flag of the entity
+ * to 1 with new_weight == weight would re-set
+ * the value of the weight to its ioprio mapping.
+ * Set the flag only if necessary.
+ */
+ if ((unsigned short)val != bfqg->entity.new_weight) {
+ bfqg->entity.new_weight = (unsigned short)val;
+ /*
+ * Make sure that the above new value has been
+ * stored in bfqg->entity.new_weight before
+ * setting the prio_changed flag. In fact,
+ * this flag may be read asynchronously (in
+ * critical sections protected by a different
+ * lock than that held here), and finding this
+ * flag set may cause the execution of the code
+ * for updating parameters whose value may
+ * depend also on bfqg->entity.new_weight (in
+ * __bfq_entity_update_weight_prio).
+ * This barrier makes sure that the new value
+ * of bfqg->entity.new_weight is correctly
+ * seen in that code.
+ */
+ smp_wmb();
+ bfqg->entity.prio_changed = 1;
}
}
+ spin_unlock_irq(&blkcg->lock);
- return entity;
+ return ret;
}
-static bool next_queue_may_preempt(struct bfq_data *bfqd)
+static ssize_t bfq_io_set_weight(struct kernfs_open_file *of,
+ char *buf, size_t nbytes,
+ loff_t off)
{
- struct bfq_sched_data *sd = &bfqd->sched_data;
+ u64 weight;
+ /* First unsigned long found in the file is used */
+ int ret = kstrtoull(strim(buf), 0, &weight);
- return sd->next_in_service != sd->in_service_entity;
+ if (ret)
+ return ret;
+
+ return bfq_io_set_weight_legacy(of_css(of), NULL, weight);
}
+static int bfqg_print_stat(struct seq_file *sf, void *v)
+{
+ blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)), blkg_prfill_stat,
+ &blkcg_policy_bfq, seq_cft(sf)->private, false);
+ return 0;
+}
-/*
- * Get next queue for service.
- */
-static struct bfq_queue *bfq_get_next_queue(struct bfq_data *bfqd)
+static int bfqg_print_rwstat(struct seq_file *sf, void *v)
{
- struct bfq_entity *entity = NULL;
- struct bfq_sched_data *sd;
- struct bfq_queue *bfqq;
+ blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)), blkg_prfill_rwstat,
+ &blkcg_policy_bfq, seq_cft(sf)->private, true);
+ return 0;
+}
- if (bfqd->busy_queues == 0)
- return NULL;
+static u64 bfqg_prfill_stat_recursive(struct seq_file *sf,
+ struct blkg_policy_data *pd, int off)
+{
+ u64 sum = blkg_stat_recursive_sum(pd_to_blkg(pd),
+ &blkcg_policy_bfq, off);
+ return __blkg_prfill_u64(sf, pd, sum);
+}
- sd = &bfqd->sched_data;
- for (; sd ; sd = entity->my_sched_data) {
- entity = bfq_lookup_next_entity(sd, 1, bfqd);
- entity->service = 0;
- }
+static u64 bfqg_prfill_rwstat_recursive(struct seq_file *sf,
+ struct blkg_policy_data *pd, int off)
+{
+ struct blkg_rwstat sum = blkg_rwstat_recursive_sum(pd_to_blkg(pd),
+ &blkcg_policy_bfq,
+ off);
+ return __blkg_prfill_rwstat(sf, pd, &sum);
+}
- bfqq = bfq_entity_to_bfqq(entity);
+static int bfqg_print_stat_recursive(struct seq_file *sf, void *v)
+{
+ blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)),
+ bfqg_prfill_stat_recursive, &blkcg_policy_bfq,
+ seq_cft(sf)->private, false);
+ return 0;
+}
- return bfqq;
+static int bfqg_print_rwstat_recursive(struct seq_file *sf, void *v)
+{
+ blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)),
+ bfqg_prfill_rwstat_recursive, &blkcg_policy_bfq,
+ seq_cft(sf)->private, true);
+ return 0;
}
-static void __bfq_bfqd_reset_in_service(struct bfq_data *bfqd)
+static u64 bfqg_prfill_sectors(struct seq_file *sf, struct blkg_policy_data *pd,
+ int off)
{
- if (bfqd->in_service_bic) {
- put_io_context(bfqd->in_service_bic->icq.ioc);
- bfqd->in_service_bic = NULL;
- }
+ u64 sum = blkg_rwstat_total(&pd->blkg->stat_bytes);
- bfq_clear_bfqq_wait_request(bfqd->in_service_queue);
- hrtimer_try_to_cancel(&bfqd->idle_slice_timer);
- bfqd->in_service_queue = NULL;
+ return __blkg_prfill_u64(sf, pd, sum >> 9);
}
-static void bfq_deactivate_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq,
- int requeue)
+static int bfqg_print_stat_sectors(struct seq_file *sf, void *v)
{
- struct bfq_entity *entity = &bfqq->entity;
-
- bfq_deactivate_entity(entity, requeue);
+ blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)),
+ bfqg_prfill_sectors, &blkcg_policy_bfq, 0, false);
+ return 0;
}
-static void bfq_activate_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq)
+static u64 bfqg_prfill_sectors_recursive(struct seq_file *sf,
+ struct blkg_policy_data *pd, int off)
{
- struct bfq_entity *entity = &bfqq->entity;
+ struct blkg_rwstat tmp = blkg_rwstat_recursive_sum(pd->blkg, NULL,
+ offsetof(struct blkcg_gq, stat_bytes));
+ u64 sum = atomic64_read(&tmp.aux_cnt[BLKG_RWSTAT_READ]) +
+ atomic64_read(&tmp.aux_cnt[BLKG_RWSTAT_WRITE]);
- bfq_activate_entity(entity, bfq_bfqq_non_blocking_wait_rq(bfqq));
- bfq_clear_bfqq_non_blocking_wait_rq(bfqq);
+ return __blkg_prfill_u64(sf, pd, sum >> 9);
}
-/*
- * 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)
+static int bfqg_print_stat_sectors_recursive(struct seq_file *sf, void *v)
{
- bfq_log_bfqq(bfqd, bfqq, "del from busy");
+ blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)),
+ bfqg_prfill_sectors_recursive, &blkcg_policy_bfq, 0,
+ false);
+ return 0;
+}
- bfq_clear_bfqq_busy(bfqq);
+#ifdef CONFIG_DEBUG_BLK_CGROUP
+static u64 bfqg_prfill_avg_queue_size(struct seq_file *sf,
+ struct blkg_policy_data *pd, int off)
+{
+ struct bfq_group *bfqg = pd_to_bfqg(pd);
+ u64 samples = blkg_stat_read(&bfqg->stats.avg_queue_size_samples);
+ u64 v = 0;
- bfqd->busy_queues--;
+ if (samples) {
+ v = blkg_stat_read(&bfqg->stats.avg_queue_size_sum);
+ v = div64_u64(v, samples);
+ }
+ __blkg_prfill_u64(sf, pd, v);
+ return 0;
+}
- bfq_deactivate_bfqq(bfqd, bfqq, requeue);
+/* print avg_queue_size */
+static int bfqg_print_avg_queue_size(struct seq_file *sf, void *v)
+{
+ blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)),
+ bfqg_prfill_avg_queue_size, &blkcg_policy_bfq,
+ 0, false);
+ return 0;
}
+#endif /* CONFIG_DEBUG_BLK_CGROUP */
-/*
- * Called when an inactive queue receives a new request.
- */
-static void bfq_add_bfqq_busy(struct bfq_data *bfqd, struct bfq_queue *bfqq)
+static struct bfq_group *
+bfq_create_group_hierarchy(struct bfq_data *bfqd, int node)
{
- bfq_log_bfqq(bfqd, bfqq, "add to busy");
+ int ret;
- bfq_activate_bfqq(bfqd, bfqq);
+ ret = blkcg_activate_policy(bfqd->queue, &blkcg_policy_bfq);
+ if (ret)
+ return NULL;
- bfq_mark_bfqq_busy(bfqq);
- bfqd->busy_queues++;
+ return blkg_to_bfqg(bfqd->queue->root_blkg);
}
-static void bfq_init_entity(struct bfq_entity *entity)
+static struct cftype bfq_blkcg_legacy_files[] = {
+ {
+ .name = "bfq.weight",
+ .flags = CFTYPE_NOT_ON_ROOT,
+ .seq_show = bfq_io_show_weight,
+ .write_u64 = bfq_io_set_weight_legacy,
+ },
+
+ /* statistics, covers only the tasks in the bfqg */
+ {
+ .name = "bfq.time",
+ .private = offsetof(struct bfq_group, stats.time),
+ .seq_show = bfqg_print_stat,
+ },
+ {
+ .name = "bfq.sectors",
+ .seq_show = bfqg_print_stat_sectors,
+ },
+ {
+ .name = "bfq.io_service_bytes",
+ .private = (unsigned long)&blkcg_policy_bfq,
+ .seq_show = blkg_print_stat_bytes,
+ },
+ {
+ .name = "bfq.io_serviced",
+ .private = (unsigned long)&blkcg_policy_bfq,
+ .seq_show = blkg_print_stat_ios,
+ },
+ {
+ .name = "bfq.io_service_time",
+ .private = offsetof(struct bfq_group, stats.service_time),
+ .seq_show = bfqg_print_rwstat,
+ },
+ {
+ .name = "bfq.io_wait_time",
+ .private = offsetof(struct bfq_group, stats.wait_time),
+ .seq_show = bfqg_print_rwstat,
+ },
+ {
+ .name = "bfq.io_merged",
+ .private = offsetof(struct bfq_group, stats.merged),
+ .seq_show = bfqg_print_rwstat,
+ },
+ {
+ .name = "bfq.io_queued",
+ .private = offsetof(struct bfq_group, stats.queued),
+ .seq_show = bfqg_print_rwstat,
+ },
+
+ /* the same statictics which cover the bfqg and its descendants */
+ {
+ .name = "bfq.time_recursive",
+ .private = offsetof(struct bfq_group, stats.time),
+ .seq_show = bfqg_print_stat_recursive,
+ },
+ {
+ .name = "bfq.sectors_recursive",
+ .seq_show = bfqg_print_stat_sectors_recursive,
+ },
+ {
+ .name = "bfq.io_service_bytes_recursive",
+ .private = (unsigned long)&blkcg_policy_bfq,
+ .seq_show = blkg_print_stat_bytes_recursive,
+ },
+ {
+ .name = "bfq.io_serviced_recursive",
+ .private = (unsigned long)&blkcg_policy_bfq,
+ .seq_show = blkg_print_stat_ios_recursive,
+ },
+ {
+ .name = "bfq.io_service_time_recursive",
+ .private = offsetof(struct bfq_group, stats.service_time),
+ .seq_show = bfqg_print_rwstat_recursive,
+ },
+ {
+ .name = "bfq.io_wait_time_recursive",
+ .private = offsetof(struct bfq_group, stats.wait_time),
+ .seq_show = bfqg_print_rwstat_recursive,
+ },
+ {
+ .name = "bfq.io_merged_recursive",
+ .private = offsetof(struct bfq_group, stats.merged),
+ .seq_show = bfqg_print_rwstat_recursive,
+ },
+ {
+ .name = "bfq.io_queued_recursive",
+ .private = offsetof(struct bfq_group, stats.queued),
+ .seq_show = bfqg_print_rwstat_recursive,
+ },
+#ifdef CONFIG_DEBUG_BLK_CGROUP
+ {
+ .name = "bfq.avg_queue_size",
+ .seq_show = bfqg_print_avg_queue_size,
+ },
+ {
+ .name = "bfq.group_wait_time",
+ .private = offsetof(struct bfq_group, stats.group_wait_time),
+ .seq_show = bfqg_print_stat,
+ },
+ {
+ .name = "bfq.idle_time",
+ .private = offsetof(struct bfq_group, stats.idle_time),
+ .seq_show = bfqg_print_stat,
+ },
+ {
+ .name = "bfq.empty_time",
+ .private = offsetof(struct bfq_group, stats.empty_time),
+ .seq_show = bfqg_print_stat,
+ },
+ {
+ .name = "bfq.dequeue",
+ .private = offsetof(struct bfq_group, stats.dequeue),
+ .seq_show = bfqg_print_stat,
+ },
+#endif /* CONFIG_DEBUG_BLK_CGROUP */
+ { } /* terminate */
+};
+
+static struct cftype bfq_blkg_files[] = {
+ {
+ .name = "bfq.weight",
+ .flags = CFTYPE_NOT_ON_ROOT,
+ .seq_show = bfq_io_show_weight,
+ .write = bfq_io_set_weight,
+ },
+ {} /* terminate */
+};
+
+#else /* CONFIG_BFQ_GROUP_IOSCHED */
+
+static inline void bfqg_stats_update_io_add(struct bfq_group *bfqg,
+ struct bfq_queue *bfqq, int op, int op_flags) { }
+static inline void
+bfqg_stats_update_io_remove(struct bfq_group *bfqg, int op, int op_flags) { }
+static inline void
+bfqg_stats_update_io_merged(struct bfq_group *bfqg, int op, int op_flags) { }
+static inline void bfqg_stats_update_completion(struct bfq_group *bfqg,
+ uint64_t start_time, uint64_t io_start_time, int op,
+ int op_flags) { }
+
+static void bfq_init_entity(struct bfq_entity *entity,
+ struct bfq_group *bfqg)
{
struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity);
entity->weight = entity->new_weight;
entity->orig_weight = entity->new_weight;
+ if (bfqq) {
+ bfqq->ioprio = bfqq->new_ioprio;
+ bfqq->ioprio_class = bfqq->new_ioprio_class;
+ }
+ entity->sched_data = &bfqg->sched_data;
+}
+
+static struct bfq_group *
+bfq_bic_update_cgroup(struct bfq_io_cq *bic, struct bio *bio)
+{
+ struct bfq_data *bfqd = bic_to_bfqd(bic);
+
+ return bfqd->root_group;
+}
- bfqq->ioprio = bfqq->new_ioprio;
- bfqq->ioprio_class = bfqq->new_ioprio_class;
+static void bfq_disconnect_groups(struct bfq_data *bfqd)
+{
+ bfq_put_async_queues(bfqd, bfqd->root_group);
+}
+
+static struct bfq_group *bfq_find_set_group(struct bfq_data *bfqd,
+ struct blkcg *blkcg)
+{
+ return bfqd->root_group;
+}
+
+static struct bfq_group *bfqq_group(struct bfq_queue *bfqq)
+{
+ return bfqq->bfqd->root_group;
+}
- entity->sched_data = &bfqq->bfqd->sched_data;
+static struct bfq_group *bfq_create_group_hierarchy(struct bfq_data *bfqd,
+ int node)
+{
+ struct bfq_group *bfqg;
+ int i;
+
+ bfqg = kmalloc_node(sizeof(*bfqg), GFP_KERNEL | __GFP_ZERO, node);
+ if (!bfqg)
+ return NULL;
+
+ for (i = 0; i < BFQ_IOPRIO_CLASSES; i++)
+ bfqg->sched_data.service_tree[i] = BFQ_SERVICE_TREE_INIT;
+
+ return bfqg;
}
+#endif /* CONFIG_BFQ_GROUP_IOSCHED */
#define bfq_class_idle(bfqq) ((bfqq)->ioprio_class == IOPRIO_CLASS_IDLE)
#define bfq_class_rt(bfqq) ((bfqq)->ioprio_class == IOPRIO_CLASS_RT)
@@ -1965,6 +3321,9 @@ static void bfq_bfqq_handle_idle_busy_switch(struct bfq_data *bfqd,
RQ_BIC(rq)->ttime.last_end_request +
bfqd->bfq_slice_idle * 3ULL;
+ bfqg_stats_update_io_add(bfqq_group(RQ_BFQQ(rq)), bfqq,
+ req_op(rq), rq->cmd_flags);
+
/*
* Update budget and check whether bfqq may want to preempt
* the in-service queue.
@@ -2099,6 +3458,9 @@ static void bfq_remove_request(struct request *rq)
if (rq->cmd_flags & REQ_META)
bfqq->meta_pending--;
+
+ bfqg_stats_update_io_remove(bfqq_group(bfqq), req_op(rq),
+ rq->cmd_flags);
}
static int bfq_merge(struct request_queue *q, struct request **req,
@@ -2145,6 +3507,15 @@ static void bfq_merged_request(struct request_queue *q, struct request *req,
}
}
+#ifdef CONFIG_BFQ_GROUP_IOSCHED
+static void bfq_bio_merged(struct request_queue *q, struct request *req,
+ struct bio *bio)
+{
+ bfqg_stats_update_io_merged(bfqq_group(RQ_BFQQ(req)), bio_op(bio),
+ bio->bi_opf);
+}
+#endif
+
static void bfq_merged_requests(struct request_queue *q, struct request *rq,
struct request *next)
{
@@ -2171,6 +3542,8 @@ static void bfq_merged_requests(struct request_queue *q, struct request *rq,
bfqq->next_rq = rq;
bfq_remove_request(next);
+ bfqg_stats_update_io_merged(bfqq_group(bfqq), req_op(next),
+ next->cmd_flags);
}
static int bfq_allow_bio_merge(struct request_queue *q, struct request *rq,
@@ -2210,6 +3583,7 @@ static void __bfq_set_in_service_queue(struct bfq_data *bfqd,
struct bfq_queue *bfqq)
{
if (bfqq) {
+ bfqg_stats_update_avg_queue_size(bfqq_group(bfqq));
bfq_mark_bfqq_must_alloc(bfqq);
bfq_mark_bfqq_budget_new(bfqq);
bfq_clear_bfqq_fifo_expire(bfqq);
@@ -2293,6 +3667,7 @@ static void bfq_arm_slice_timer(struct bfq_data *bfqd)
bfqd->last_idling_start = ktime_get();
hrtimer_start(&bfqd->idle_slice_timer, ns_to_ktime(sl),
HRTIMER_MODE_REL);
+ bfqg_stats_set_start_idle_time(bfqq_group(bfqq));
}
/*
@@ -2824,6 +4199,7 @@ static struct bfq_queue *bfq_select_queue(struct bfq_data *bfqd)
*/
bfq_clear_bfqq_wait_request(bfqq);
hrtimer_try_to_cancel(&bfqd->idle_slice_timer);
+ bfqg_stats_update_idle_time(bfqq_group(bfqq));
}
goto keep_queue;
}
@@ -3013,11 +4389,18 @@ static int bfq_dispatch_requests(struct request_queue *q, int force)
*/
static void bfq_put_queue(struct bfq_queue *bfqq)
{
+#ifdef CONFIG_BFQ_GROUP_IOSCHED
+ struct bfq_group *bfqg = bfqq_group(bfqq);
+#endif
+
bfqq->ref--;
if (bfqq->ref)
return;
kmem_cache_free(bfq_pool, bfqq);
+#ifdef CONFIG_BFQ_GROUP_IOSCHED
+ bfqg_put(bfqg);
+#endif
}
static void bfq_exit_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq)
@@ -3159,18 +4542,19 @@ static void bfq_init_bfqq(struct bfq_data *bfqd, struct bfq_queue *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 &async_bfqq[0][ioprio];
+ return &bfqg->async_bfqq[0][ioprio];
case IOPRIO_CLASS_NONE:
ioprio = IOPRIO_NORM;
/* fall through */
case IOPRIO_CLASS_BE:
- return &async_bfqq[1][ioprio];
+ return &bfqg->async_bfqq[1][ioprio];
case IOPRIO_CLASS_IDLE:
- return &async_idle_bfqq;
+ return &bfqg->async_idle_bfqq;
default:
return NULL;
}
@@ -3184,11 +4568,18 @@ static struct bfq_queue *bfq_get_queue(struct bfq_data *bfqd,
const int ioprio_class = IOPRIO_PRIO_CLASS(bic->ioprio);
struct bfq_queue **async_bfqq = NULL;
struct bfq_queue *bfqq;
+ struct bfq_group *bfqg;
rcu_read_lock();
+ bfqg = bfq_find_set_group(bfqd, bio_blkcg(bio));
+ if (!bfqg) {
+ bfqq = &bfqd->oom_bfqq;
+ goto out;
+ }
+
if (!is_sync) {
- async_bfqq = bfq_async_queue_prio(bfqd, ioprio_class,
+ async_bfqq = bfq_async_queue_prio(bfqd, bfqg, ioprio_class,
ioprio);
bfqq = *async_bfqq;
if (bfqq)
@@ -3201,7 +4592,7 @@ static struct bfq_queue *bfq_get_queue(struct bfq_data *bfqd,
if (bfqq) {
bfq_init_bfqq(bfqd, bfqq, bic, current->pid,
is_sync);
- bfq_init_entity(&bfqq->entity);
+ bfq_init_entity(&bfqq->entity, bfqg);
bfq_log_bfqq(bfqd, bfqq, "allocated");
} else {
bfqq = &bfqd->oom_bfqq;
@@ -3349,6 +4740,7 @@ static void bfq_rq_enqueued(struct bfq_data *bfqd, struct bfq_queue *bfqq,
*/
bfq_clear_bfqq_wait_request(bfqq);
hrtimer_try_to_cancel(&bfqd->idle_slice_timer);
+ bfqg_stats_update_idle_time(bfqq_group(bfqq));
/*
* The queue is not empty, because a new request just
@@ -3418,6 +4810,10 @@ static void bfq_completed_request(struct request_queue *q, struct request *rq)
bfqd->rq_in_driver--;
bfqq->dispatched--;
+ bfqg_stats_update_completion(bfqq_group(bfqq),
+ rq_start_time_ns(rq),
+ rq_io_start_time_ns(rq), req_op(rq),
+ rq->cmd_flags);
RQ_BIC(rq)->ttime.last_end_request = ktime_get_ns();
@@ -3524,6 +4920,8 @@ static int bfq_set_request(struct request_queue *q, struct request *rq,
if (!bic)
goto queue_fail;
+ bfq_bic_update_cgroup(bic, bio);
+
bfqq = bic_to_bfqq(bic, is_sync);
if (!bfqq || bfqq == &bfqd->oom_bfqq) {
if (bfqq)
@@ -3629,6 +5027,9 @@ static void __bfq_put_async_bfqq(struct bfq_data *bfqd,
bfq_log(bfqd, "put_async_bfqq: %p", bfqq);
if (bfqq) {
+#ifdef CONFIG_BFQ_GROUP_IOSCHED
+ bfq_bfqq_move(bfqd, bfqq, bfqd->root_group);
+#endif
bfq_log_bfqq(bfqd, bfqq, "put_async_bfqq: putting %p, %d",
bfqq, bfqq->ref);
bfq_put_queue(bfqq);
@@ -3637,18 +5038,20 @@ static void __bfq_put_async_bfqq(struct bfq_data *bfqd,
}
/*
- * Release the extra reference of the async queues as the device
- * goes away.
+ * 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 until all the requests on a device are gone).
*/
-static void bfq_put_async_queues(struct bfq_data *bfqd)
+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, &async_bfqq[i][j]);
+ __bfq_put_async_bfqq(bfqd, &bfqg->async_bfqq[i][j]);
- __bfq_put_async_bfqq(bfqd, &async_idle_bfqq);
+ __bfq_put_async_bfqq(bfqd, &bfqg->async_idle_bfqq);
}
static void bfq_exit_queue(struct elevator_queue *e)
@@ -3664,19 +5067,40 @@ static void bfq_exit_queue(struct elevator_queue *e)
list_for_each_entry_safe(bfqq, n, &bfqd->idle_list, bfqq_list)
bfq_deactivate_bfqq(bfqd, bfqq, 0);
- bfq_put_async_queues(bfqd);
+#ifndef CONFIG_BFQ_GROUP_IOSCHED
+ bfq_disconnect_groups(bfqd);
+#endif
spin_unlock_irq(q->queue_lock);
bfq_shutdown_timer_wq(bfqd);
+#ifdef CONFIG_BFQ_GROUP_IOSCHED
+ blkcg_deactivate_policy(q, &blkcg_policy_bfq);
+#else
+ kfree(bfqd->root_group);
+#endif
+
kfree(bfqd);
}
+static void bfq_init_root_group(struct bfq_group *root_group,
+ struct bfq_data *bfqd)
+{
+ int i;
+
+#ifdef CONFIG_BFQ_GROUP_IOSCHED
+ root_group->entity.parent = NULL;
+ root_group->my_entity = NULL;
+ root_group->bfqd = bfqd;
+#endif
+ for (i = 0; i < BFQ_IOPRIO_CLASSES; i++)
+ root_group->sched_data.service_tree[i] = BFQ_SERVICE_TREE_INIT;
+}
+
static int bfq_init_queue(struct request_queue *q, struct elevator_type *e)
{
struct bfq_data *bfqd;
struct elevator_queue *eq;
- int i;
eq = elevator_alloc(q, e);
if (!eq)
@@ -3713,8 +5137,11 @@ static int bfq_init_queue(struct request_queue *q, struct elevator_type *e)
q->elevator = eq;
spin_unlock_irq(q->queue_lock);
- for (i = 0; i < BFQ_IOPRIO_CLASSES; i++)
- bfqd->sched_data.service_tree[i] = BFQ_SERVICE_TREE_INIT;
+ bfqd->root_group = bfq_create_group_hierarchy(bfqd, q->node);
+ if (!bfqd->root_group)
+ goto out_free;
+ bfq_init_root_group(bfqd->root_group, bfqd);
+ bfq_init_entity(&bfqd->oom_bfqq.entity, bfqd->root_group);
hrtimer_init(&bfqd->idle_slice_timer, CLOCK_MONOTONIC,
HRTIMER_MODE_REL);
@@ -3740,6 +5167,11 @@ static int bfq_init_queue(struct request_queue *q, struct elevator_type *e)
bfqd->bfq_requests_within_timer = 120;
return 0;
+
+out_free:
+ kfree(bfqd);
+ kobject_put(&eq->kobj);
+ return -ENOMEM;
}
static void bfq_slab_kill(void)
@@ -3986,6 +5418,9 @@ static struct elevator_type iosched_bfq = {
.elevator_merge_req_fn = bfq_merged_requests,
.elevator_allow_bio_merge_fn = bfq_allow_bio_merge,
.elevator_allow_rq_merge_fn = bfq_allow_rq_merge,
+#ifdef CONFIG_BFQ_GROUP_IOSCHED
+ .elevator_bio_merged_fn = bfq_bio_merged,
+#endif
.elevator_dispatch_fn = bfq_dispatch_requests,
.elevator_add_req_fn = bfq_insert_request,
.elevator_activate_req_fn = bfq_activate_request,
@@ -4008,11 +5443,35 @@ static struct elevator_type iosched_bfq = {
.elevator_owner = THIS_MODULE,
};
+#ifdef CONFIG_BFQ_GROUP_IOSCHED
+static struct blkcg_policy blkcg_policy_bfq = {
+ .dfl_cftypes = bfq_blkg_files,
+ .legacy_cftypes = bfq_blkcg_legacy_files,
+
+ .cpd_alloc_fn = bfq_cpd_alloc,
+ .cpd_init_fn = bfq_cpd_init,
+ .cpd_bind_fn = bfq_cpd_init,
+ .cpd_free_fn = bfq_cpd_free,
+
+ .pd_alloc_fn = bfq_pd_alloc,
+ .pd_init_fn = bfq_pd_init,
+ .pd_offline_fn = bfq_pd_offline,
+ .pd_free_fn = bfq_pd_free,
+ .pd_reset_stats_fn = bfq_pd_reset_stats,
+};
+#endif
+
static int __init bfq_init(void)
{
int ret;
char msg[50] = "BFQ I/O-scheduler: v0";
+#ifdef CONFIG_BFQ_GROUP_IOSCHED
+ ret = blkcg_policy_register(&blkcg_policy_bfq);
+ if (ret)
+ return ret;
+#endif
+
ret = -ENOMEM;
if (bfq_slab_setup())
goto err_pol_unreg;
@@ -4029,11 +5488,17 @@ static int __init bfq_init(void)
return 0;
err_pol_unreg:
+#ifdef CONFIG_BFQ_GROUP_IOSCHED
+ blkcg_policy_unregister(&blkcg_policy_bfq);
+#endif
return ret;
}
static void __exit bfq_exit(void)
{
+#ifdef CONFIG_BFQ_GROUP_IOSCHED
+ blkcg_policy_unregister(&blkcg_policy_bfq);
+#endif
elv_unregister(&iosched_bfq);
bfq_slab_kill();
}
@@ -45,7 +45,7 @@ struct pr_ops;
* Maximum number of blkcg policies allowed to be registered concurrently.
* Defined here to simplify include dependency.
*/
-#define BLKCG_MAX_POLS 2
+#define BLKCG_MAX_POLS 3
typedef void (rq_end_io_fn)(struct request *, int);