* Nauman Rafique <nauman@google.com>
*/
#include <linux/ioprio.h>
-#include <linux/seq_file.h>
#include <linux/kdev_t.h>
#include <linux/module.h>
#include <linux/err.h>
#include <linux/blkdev.h>
#include <linux/slab.h>
-#include "blk-cgroup.h"
#include <linux/genhd.h>
+#include <linux/delay.h>
+#include <linux/atomic.h>
+#include "blk-cgroup.h"
+#include "blk.h"
#define MAX_KEY_LEN 100
-static DEFINE_SPINLOCK(blkio_list_lock);
-static LIST_HEAD(blkio_list);
+static DEFINE_MUTEX(blkcg_pol_mutex);
-struct blkio_cgroup blkio_root_cgroup = { .weight = 2*BLKIO_WEIGHT_DEFAULT };
+struct blkio_cgroup blkio_root_cgroup = { .cfq_weight = 2 * CFQ_WEIGHT_DEFAULT };
EXPORT_SYMBOL_GPL(blkio_root_cgroup);
-/* for encoding cft->private value on file */
-#define BLKIOFILE_PRIVATE(x, val) (((x) << 16) | (val))
-/* What policy owns the file, proportional or throttle */
-#define BLKIOFILE_POLICY(val) (((val) >> 16) & 0xffff)
-#define BLKIOFILE_ATTR(val) ((val) & 0xffff)
-
-static inline void blkio_policy_insert_node(struct blkio_cgroup *blkcg,
- struct blkio_policy_node *pn)
-{
- list_add(&pn->node, &blkcg->policy_list);
-}
-
-static inline bool cftype_blkg_same_policy(struct cftype *cft,
- struct blkio_group *blkg)
-{
- enum blkio_policy_id plid = BLKIOFILE_POLICY(cft->private);
-
- if (blkg->plid == plid)
- return 1;
-
- return 0;
-}
-
-/* Determines if policy node matches cgroup file being accessed */
-static inline bool pn_matches_cftype(struct cftype *cft,
- struct blkio_policy_node *pn)
-{
- enum blkio_policy_id plid = BLKIOFILE_POLICY(cft->private);
- int fileid = BLKIOFILE_ATTR(cft->private);
-
- return (plid == pn->plid && fileid == pn->fileid);
-}
-
-/* Must be called with blkcg->lock held */
-static inline void blkio_policy_delete_node(struct blkio_policy_node *pn)
-{
- list_del(&pn->node);
-}
-
-/* Must be called with blkcg->lock held */
-static struct blkio_policy_node *
-blkio_policy_search_node(const struct blkio_cgroup *blkcg, dev_t dev,
- enum blkio_policy_id plid, int fileid)
-{
- struct blkio_policy_node *pn;
-
- list_for_each_entry(pn, &blkcg->policy_list, node) {
- if (pn->dev == dev && pn->plid == plid && pn->fileid == fileid)
- return pn;
- }
-
- return NULL;
-}
+static struct blkio_policy_type *blkio_policy[BLKCG_MAX_POLS];
struct blkio_cgroup *cgroup_to_blkio_cgroup(struct cgroup *cgroup)
{
}
EXPORT_SYMBOL_GPL(cgroup_to_blkio_cgroup);
-struct blkio_cgroup *task_blkio_cgroup(struct task_struct *tsk)
+static struct blkio_cgroup *task_blkio_cgroup(struct task_struct *tsk)
{
return container_of(task_subsys_state(tsk, blkio_subsys_id),
struct blkio_cgroup, css);
}
-EXPORT_SYMBOL_GPL(task_blkio_cgroup);
-
-static inline void
-blkio_update_group_weight(struct blkio_group *blkg, unsigned int weight)
-{
- struct blkio_policy_type *blkiop;
-
- list_for_each_entry(blkiop, &blkio_list, list) {
- /* If this policy does not own the blkg, do not send updates */
- if (blkiop->plid != blkg->plid)
- continue;
- if (blkiop->ops.blkio_update_group_weight_fn)
- blkiop->ops.blkio_update_group_weight_fn(blkg->key,
- blkg, weight);
- }
-}
-static inline void blkio_update_group_bps(struct blkio_group *blkg, u64 bps,
- int fileid)
+struct blkio_cgroup *bio_blkio_cgroup(struct bio *bio)
{
- struct blkio_policy_type *blkiop;
-
- list_for_each_entry(blkiop, &blkio_list, list) {
-
- /* If this policy does not own the blkg, do not send updates */
- if (blkiop->plid != blkg->plid)
- continue;
-
- if (fileid == BLKIO_THROTL_read_bps_device
- && blkiop->ops.blkio_update_group_read_bps_fn)
- blkiop->ops.blkio_update_group_read_bps_fn(blkg->key,
- blkg, bps);
-
- if (fileid == BLKIO_THROTL_write_bps_device
- && blkiop->ops.blkio_update_group_write_bps_fn)
- blkiop->ops.blkio_update_group_write_bps_fn(blkg->key,
- blkg, bps);
- }
+ if (bio && bio->bi_css)
+ return container_of(bio->bi_css, struct blkio_cgroup, css);
+ return task_blkio_cgroup(current);
}
+EXPORT_SYMBOL_GPL(bio_blkio_cgroup);
-static inline void blkio_update_group_iops(struct blkio_group *blkg,
- unsigned int iops, int fileid)
+static bool blkcg_policy_enabled(struct request_queue *q,
+ const struct blkio_policy_type *pol)
{
- struct blkio_policy_type *blkiop;
-
- list_for_each_entry(blkiop, &blkio_list, list) {
-
- /* If this policy does not own the blkg, do not send updates */
- if (blkiop->plid != blkg->plid)
- continue;
-
- if (fileid == BLKIO_THROTL_read_iops_device
- && blkiop->ops.blkio_update_group_read_iops_fn)
- blkiop->ops.blkio_update_group_read_iops_fn(blkg->key,
- blkg, iops);
-
- if (fileid == BLKIO_THROTL_write_iops_device
- && blkiop->ops.blkio_update_group_write_iops_fn)
- blkiop->ops.blkio_update_group_write_iops_fn(blkg->key,
- blkg,iops);
- }
+ return pol && test_bit(pol->plid, q->blkcg_pols);
}
-/*
- * Add to the appropriate stat variable depending on the request type.
- * This should be called with the blkg->stats_lock held.
- */
-static void blkio_add_stat(uint64_t *stat, uint64_t add, bool direction,
- bool sync)
+static size_t blkg_pd_size(const struct blkio_policy_type *pol)
{
- if (direction)
- stat[BLKIO_STAT_WRITE] += add;
- else
- stat[BLKIO_STAT_READ] += add;
- if (sync)
- stat[BLKIO_STAT_SYNC] += add;
- else
- stat[BLKIO_STAT_ASYNC] += add;
+ return sizeof(struct blkg_policy_data) + pol->pdata_size;
}
-/*
- * Decrements the appropriate stat variable if non-zero depending on the
- * request type. Panics on value being zero.
- * This should be called with the blkg->stats_lock held.
+/**
+ * blkg_free - free a blkg
+ * @blkg: blkg to free
+ *
+ * Free @blkg which may be partially allocated.
*/
-static void blkio_check_and_dec_stat(uint64_t *stat, bool direction, bool sync)
+static void blkg_free(struct blkio_group *blkg)
{
- if (direction) {
- BUG_ON(stat[BLKIO_STAT_WRITE] == 0);
- stat[BLKIO_STAT_WRITE]--;
- } else {
- BUG_ON(stat[BLKIO_STAT_READ] == 0);
- stat[BLKIO_STAT_READ]--;
- }
- if (sync) {
- BUG_ON(stat[BLKIO_STAT_SYNC] == 0);
- stat[BLKIO_STAT_SYNC]--;
- } else {
- BUG_ON(stat[BLKIO_STAT_ASYNC] == 0);
- stat[BLKIO_STAT_ASYNC]--;
- }
-}
+ int i;
-#ifdef CONFIG_DEBUG_BLK_CGROUP
-/* This should be called with the blkg->stats_lock held. */
-static void blkio_set_start_group_wait_time(struct blkio_group *blkg,
- struct blkio_group *curr_blkg)
-{
- if (blkio_blkg_waiting(&blkg->stats))
+ if (!blkg)
return;
- if (blkg == curr_blkg)
- return;
- blkg->stats.start_group_wait_time = sched_clock();
- blkio_mark_blkg_waiting(&blkg->stats);
-}
-/* This should be called with the blkg->stats_lock held. */
-static void blkio_update_group_wait_time(struct blkio_group_stats *stats)
-{
- unsigned long long now;
-
- if (!blkio_blkg_waiting(stats))
- return;
+ for (i = 0; i < BLKCG_MAX_POLS; i++) {
+ struct blkio_policy_type *pol = blkio_policy[i];
+ struct blkg_policy_data *pd = blkg->pd[i];
- now = sched_clock();
- if (time_after64(now, stats->start_group_wait_time))
- stats->group_wait_time += now - stats->start_group_wait_time;
- blkio_clear_blkg_waiting(stats);
-}
+ if (!pd)
+ continue;
-/* This should be called with the blkg->stats_lock held. */
-static void blkio_end_empty_time(struct blkio_group_stats *stats)
-{
- unsigned long long now;
+ if (pol && pol->ops.blkio_exit_group_fn)
+ pol->ops.blkio_exit_group_fn(blkg);
- if (!blkio_blkg_empty(stats))
- return;
+ kfree(pd);
+ }
- now = sched_clock();
- if (time_after64(now, stats->start_empty_time))
- stats->empty_time += now - stats->start_empty_time;
- blkio_clear_blkg_empty(stats);
+ kfree(blkg);
}
-void blkiocg_update_set_idle_time_stats(struct blkio_group *blkg)
+/**
+ * blkg_alloc - allocate a blkg
+ * @blkcg: block cgroup the new blkg is associated with
+ * @q: request_queue the new blkg is associated with
+ *
+ * Allocate a new blkg assocating @blkcg and @q.
+ */
+static struct blkio_group *blkg_alloc(struct blkio_cgroup *blkcg,
+ struct request_queue *q)
{
- unsigned long flags;
+ struct blkio_group *blkg;
+ int i;
- spin_lock_irqsave(&blkg->stats_lock, flags);
- BUG_ON(blkio_blkg_idling(&blkg->stats));
- blkg->stats.start_idle_time = sched_clock();
- blkio_mark_blkg_idling(&blkg->stats);
- spin_unlock_irqrestore(&blkg->stats_lock, flags);
-}
-EXPORT_SYMBOL_GPL(blkiocg_update_set_idle_time_stats);
+ /* alloc and init base part */
+ blkg = kzalloc_node(sizeof(*blkg), GFP_ATOMIC, q->node);
+ if (!blkg)
+ return NULL;
-void blkiocg_update_idle_time_stats(struct blkio_group *blkg)
-{
- unsigned long flags;
- unsigned long long now;
- struct blkio_group_stats *stats;
-
- spin_lock_irqsave(&blkg->stats_lock, flags);
- stats = &blkg->stats;
- if (blkio_blkg_idling(stats)) {
- now = sched_clock();
- if (time_after64(now, stats->start_idle_time))
- stats->idle_time += now - stats->start_idle_time;
- blkio_clear_blkg_idling(stats);
- }
- spin_unlock_irqrestore(&blkg->stats_lock, flags);
-}
-EXPORT_SYMBOL_GPL(blkiocg_update_idle_time_stats);
+ blkg->q = q;
+ INIT_LIST_HEAD(&blkg->q_node);
+ blkg->blkcg = blkcg;
+ blkg->refcnt = 1;
+ cgroup_path(blkcg->css.cgroup, blkg->path, sizeof(blkg->path));
-void blkiocg_update_avg_queue_size_stats(struct blkio_group *blkg)
-{
- unsigned long flags;
- struct blkio_group_stats *stats;
-
- spin_lock_irqsave(&blkg->stats_lock, flags);
- stats = &blkg->stats;
- stats->avg_queue_size_sum +=
- stats->stat_arr[BLKIO_STAT_QUEUED][BLKIO_STAT_READ] +
- stats->stat_arr[BLKIO_STAT_QUEUED][BLKIO_STAT_WRITE];
- stats->avg_queue_size_samples++;
- blkio_update_group_wait_time(stats);
- spin_unlock_irqrestore(&blkg->stats_lock, flags);
-}
-EXPORT_SYMBOL_GPL(blkiocg_update_avg_queue_size_stats);
+ for (i = 0; i < BLKCG_MAX_POLS; i++) {
+ struct blkio_policy_type *pol = blkio_policy[i];
+ struct blkg_policy_data *pd;
-void blkiocg_set_start_empty_time(struct blkio_group *blkg)
-{
- unsigned long flags;
- struct blkio_group_stats *stats;
+ if (!blkcg_policy_enabled(q, pol))
+ continue;
- spin_lock_irqsave(&blkg->stats_lock, flags);
- stats = &blkg->stats;
+ /* alloc per-policy data and attach it to blkg */
+ pd = kzalloc_node(blkg_pd_size(pol), GFP_ATOMIC, q->node);
+ if (!pd) {
+ blkg_free(blkg);
+ return NULL;
+ }
- if (stats->stat_arr[BLKIO_STAT_QUEUED][BLKIO_STAT_READ] ||
- stats->stat_arr[BLKIO_STAT_QUEUED][BLKIO_STAT_WRITE]) {
- spin_unlock_irqrestore(&blkg->stats_lock, flags);
- return;
+ blkg->pd[i] = pd;
+ pd->blkg = blkg;
}
- /*
- * group is already marked empty. This can happen if cfqq 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(blkio_blkg_empty(stats)) {
- spin_unlock_irqrestore(&blkg->stats_lock, flags);
- return;
- }
+ /* invoke per-policy init */
+ for (i = 0; i < BLKCG_MAX_POLS; i++) {
+ struct blkio_policy_type *pol = blkio_policy[i];
- stats->start_empty_time = sched_clock();
- blkio_mark_blkg_empty(stats);
- spin_unlock_irqrestore(&blkg->stats_lock, flags);
-}
-EXPORT_SYMBOL_GPL(blkiocg_set_start_empty_time);
+ if (blkcg_policy_enabled(blkg->q, pol))
+ pol->ops.blkio_init_group_fn(blkg);
+ }
-void blkiocg_update_dequeue_stats(struct blkio_group *blkg,
- unsigned long dequeue)
-{
- blkg->stats.dequeue += dequeue;
-}
-EXPORT_SYMBOL_GPL(blkiocg_update_dequeue_stats);
-#else
-static inline void blkio_set_start_group_wait_time(struct blkio_group *blkg,
- struct blkio_group *curr_blkg) {}
-static inline void blkio_end_empty_time(struct blkio_group_stats *stats) {}
-#endif
-
-void blkiocg_update_io_add_stats(struct blkio_group *blkg,
- struct blkio_group *curr_blkg, bool direction,
- bool sync)
-{
- unsigned long flags;
-
- spin_lock_irqsave(&blkg->stats_lock, flags);
- blkio_add_stat(blkg->stats.stat_arr[BLKIO_STAT_QUEUED], 1, direction,
- sync);
- blkio_end_empty_time(&blkg->stats);
- blkio_set_start_group_wait_time(blkg, curr_blkg);
- spin_unlock_irqrestore(&blkg->stats_lock, flags);
+ return blkg;
}
-EXPORT_SYMBOL_GPL(blkiocg_update_io_add_stats);
-void blkiocg_update_io_remove_stats(struct blkio_group *blkg,
- bool direction, bool sync)
+static struct blkio_group *__blkg_lookup(struct blkio_cgroup *blkcg,
+ struct request_queue *q)
{
- unsigned long flags;
-
- spin_lock_irqsave(&blkg->stats_lock, flags);
- blkio_check_and_dec_stat(blkg->stats.stat_arr[BLKIO_STAT_QUEUED],
- direction, sync);
- spin_unlock_irqrestore(&blkg->stats_lock, flags);
-}
-EXPORT_SYMBOL_GPL(blkiocg_update_io_remove_stats);
+ struct blkio_group *blkg;
+ struct hlist_node *n;
-void blkiocg_update_timeslice_used(struct blkio_group *blkg, unsigned long time,
- unsigned long unaccounted_time)
-{
- unsigned long flags;
-
- spin_lock_irqsave(&blkg->stats_lock, flags);
- blkg->stats.time += time;
-#ifdef CONFIG_DEBUG_BLK_CGROUP
- blkg->stats.unaccounted_time += unaccounted_time;
-#endif
- spin_unlock_irqrestore(&blkg->stats_lock, flags);
+ hlist_for_each_entry_rcu(blkg, n, &blkcg->blkg_list, blkcg_node)
+ if (blkg->q == q)
+ return blkg;
+ return NULL;
}
-EXPORT_SYMBOL_GPL(blkiocg_update_timeslice_used);
-/*
- * should be called under rcu read lock or queue lock to make sure blkg pointer
- * is valid.
+/**
+ * blkg_lookup - lookup blkg for the specified blkcg - q pair
+ * @blkcg: blkcg of interest
+ * @q: request_queue of interest
+ *
+ * Lookup blkg for the @blkcg - @q pair. This function should be called
+ * under RCU read lock and is guaranteed to return %NULL if @q is bypassing
+ * - see blk_queue_bypass_start() for details.
*/
-void blkiocg_update_dispatch_stats(struct blkio_group *blkg,
- uint64_t bytes, bool direction, bool sync)
+struct blkio_group *blkg_lookup(struct blkio_cgroup *blkcg,
+ struct request_queue *q)
{
- struct blkio_group_stats_cpu *stats_cpu;
- unsigned long flags;
+ WARN_ON_ONCE(!rcu_read_lock_held());
- /*
- * Disabling interrupts to provide mutual exclusion between two
- * writes on same cpu. It probably is not needed for 64bit. Not
- * optimizing that case yet.
- */
- local_irq_save(flags);
-
- stats_cpu = this_cpu_ptr(blkg->stats_cpu);
-
- u64_stats_update_begin(&stats_cpu->syncp);
- stats_cpu->sectors += bytes >> 9;
- blkio_add_stat(stats_cpu->stat_arr_cpu[BLKIO_STAT_CPU_SERVICED],
- 1, direction, sync);
- blkio_add_stat(stats_cpu->stat_arr_cpu[BLKIO_STAT_CPU_SERVICE_BYTES],
- bytes, direction, sync);
- u64_stats_update_end(&stats_cpu->syncp);
- local_irq_restore(flags);
+ if (unlikely(blk_queue_bypass(q)))
+ return NULL;
+ return __blkg_lookup(blkcg, q);
}
-EXPORT_SYMBOL_GPL(blkiocg_update_dispatch_stats);
+EXPORT_SYMBOL_GPL(blkg_lookup);
-void blkiocg_update_completion_stats(struct blkio_group *blkg,
- uint64_t start_time, uint64_t io_start_time, bool direction, bool sync)
+static struct blkio_group *__blkg_lookup_create(struct blkio_cgroup *blkcg,
+ struct request_queue *q)
+ __releases(q->queue_lock) __acquires(q->queue_lock)
{
- struct blkio_group_stats *stats;
- unsigned long flags;
- unsigned long long now = sched_clock();
-
- spin_lock_irqsave(&blkg->stats_lock, flags);
- stats = &blkg->stats;
- if (time_after64(now, io_start_time))
- blkio_add_stat(stats->stat_arr[BLKIO_STAT_SERVICE_TIME],
- now - io_start_time, direction, sync);
- if (time_after64(io_start_time, start_time))
- blkio_add_stat(stats->stat_arr[BLKIO_STAT_WAIT_TIME],
- io_start_time - start_time, direction, sync);
- spin_unlock_irqrestore(&blkg->stats_lock, flags);
-}
-EXPORT_SYMBOL_GPL(blkiocg_update_completion_stats);
+ struct blkio_group *blkg;
-/* Merged stats are per cpu. */
-void blkiocg_update_io_merged_stats(struct blkio_group *blkg, bool direction,
- bool sync)
-{
- struct blkio_group_stats_cpu *stats_cpu;
- unsigned long flags;
+ WARN_ON_ONCE(!rcu_read_lock_held());
+ lockdep_assert_held(q->queue_lock);
+
+ blkg = __blkg_lookup(blkcg, q);
+ if (blkg)
+ return blkg;
+
+ /* blkg holds a reference to blkcg */
+ if (!css_tryget(&blkcg->css))
+ return ERR_PTR(-EINVAL);
/*
- * Disabling interrupts to provide mutual exclusion between two
- * writes on same cpu. It probably is not needed for 64bit. Not
- * optimizing that case yet.
+ * Allocate and initialize.
*/
- local_irq_save(flags);
+ blkg = blkg_alloc(blkcg, q);
- stats_cpu = this_cpu_ptr(blkg->stats_cpu);
+ /* did alloc fail? */
+ if (unlikely(!blkg)) {
+ blkg = ERR_PTR(-ENOMEM);
+ goto out;
+ }
- u64_stats_update_begin(&stats_cpu->syncp);
- blkio_add_stat(stats_cpu->stat_arr_cpu[BLKIO_STAT_CPU_MERGED], 1,
- direction, sync);
- u64_stats_update_end(&stats_cpu->syncp);
- local_irq_restore(flags);
+ /* insert */
+ spin_lock(&blkcg->lock);
+ hlist_add_head_rcu(&blkg->blkcg_node, &blkcg->blkg_list);
+ list_add(&blkg->q_node, &q->blkg_list);
+ spin_unlock(&blkcg->lock);
+out:
+ return blkg;
}
-EXPORT_SYMBOL_GPL(blkiocg_update_io_merged_stats);
-/*
- * This function allocates the per cpu stats for blkio_group. Should be called
- * from sleepable context as alloc_per_cpu() requires that.
- */
-int blkio_alloc_blkg_stats(struct blkio_group *blkg)
+struct blkio_group *blkg_lookup_create(struct blkio_cgroup *blkcg,
+ struct request_queue *q)
{
- /* Allocate memory for per cpu stats */
- blkg->stats_cpu = alloc_percpu(struct blkio_group_stats_cpu);
- if (!blkg->stats_cpu)
- return -ENOMEM;
- return 0;
+ /*
+ * This could be the first entry point of blkcg implementation and
+ * we shouldn't allow anything to go through for a bypassing queue.
+ */
+ if (unlikely(blk_queue_bypass(q)))
+ return ERR_PTR(blk_queue_dead(q) ? -EINVAL : -EBUSY);
+ return __blkg_lookup_create(blkcg, q);
}
-EXPORT_SYMBOL_GPL(blkio_alloc_blkg_stats);
+EXPORT_SYMBOL_GPL(blkg_lookup_create);
-void blkiocg_add_blkio_group(struct blkio_cgroup *blkcg,
- struct blkio_group *blkg, void *key, dev_t dev,
- enum blkio_policy_id plid)
+static void blkg_destroy(struct blkio_group *blkg)
{
- unsigned long flags;
+ struct request_queue *q = blkg->q;
+ struct blkio_cgroup *blkcg = blkg->blkcg;
- spin_lock_irqsave(&blkcg->lock, flags);
- spin_lock_init(&blkg->stats_lock);
- rcu_assign_pointer(blkg->key, key);
- blkg->blkcg_id = css_id(&blkcg->css);
- hlist_add_head_rcu(&blkg->blkcg_node, &blkcg->blkg_list);
- blkg->plid = plid;
- spin_unlock_irqrestore(&blkcg->lock, flags);
- /* Need to take css reference ? */
- cgroup_path(blkcg->css.cgroup, blkg->path, sizeof(blkg->path));
- blkg->dev = dev;
-}
-EXPORT_SYMBOL_GPL(blkiocg_add_blkio_group);
+ lockdep_assert_held(q->queue_lock);
+ lockdep_assert_held(&blkcg->lock);
-static void __blkiocg_del_blkio_group(struct blkio_group *blkg)
-{
+ /* Something wrong if we are trying to remove same group twice */
+ WARN_ON_ONCE(list_empty(&blkg->q_node));
+ WARN_ON_ONCE(hlist_unhashed(&blkg->blkcg_node));
+ list_del_init(&blkg->q_node);
hlist_del_init_rcu(&blkg->blkcg_node);
- blkg->blkcg_id = 0;
+
+ /*
+ * Put the reference taken at the time of creation so that when all
+ * queues are gone, group can be destroyed.
+ */
+ blkg_put(blkg);
}
-/*
- * returns 0 if blkio_group was still on cgroup list. Otherwise returns 1
- * indicating that blk_group was unhashed by the time we got to it.
+/**
+ * blkg_destroy_all - destroy all blkgs associated with a request_queue
+ * @q: request_queue of interest
+ *
+ * Destroy all blkgs associated with @q.
*/
-int blkiocg_del_blkio_group(struct blkio_group *blkg)
+static void blkg_destroy_all(struct request_queue *q)
{
- struct blkio_cgroup *blkcg;
- unsigned long flags;
- struct cgroup_subsys_state *css;
- int ret = 1;
-
- rcu_read_lock();
- css = css_lookup(&blkio_subsys, blkg->blkcg_id);
- if (css) {
- blkcg = container_of(css, struct blkio_cgroup, css);
- spin_lock_irqsave(&blkcg->lock, flags);
- if (!hlist_unhashed(&blkg->blkcg_node)) {
- __blkiocg_del_blkio_group(blkg);
- ret = 0;
- }
- spin_unlock_irqrestore(&blkcg->lock, flags);
- }
+ struct blkio_group *blkg, *n;
- rcu_read_unlock();
- return ret;
-}
-EXPORT_SYMBOL_GPL(blkiocg_del_blkio_group);
+ lockdep_assert_held(q->queue_lock);
-/* called under rcu_read_lock(). */
-struct blkio_group *blkiocg_lookup_group(struct blkio_cgroup *blkcg, void *key)
-{
- struct blkio_group *blkg;
- struct hlist_node *n;
- void *__key;
+ list_for_each_entry_safe(blkg, n, &q->blkg_list, q_node) {
+ struct blkio_cgroup *blkcg = blkg->blkcg;
- hlist_for_each_entry_rcu(blkg, n, &blkcg->blkg_list, blkcg_node) {
- __key = blkg->key;
- if (__key == key)
- return blkg;
+ spin_lock(&blkcg->lock);
+ blkg_destroy(blkg);
+ spin_unlock(&blkcg->lock);
}
+}
- return NULL;
+static void blkg_rcu_free(struct rcu_head *rcu_head)
+{
+ blkg_free(container_of(rcu_head, struct blkio_group, rcu_head));
}
-EXPORT_SYMBOL_GPL(blkiocg_lookup_group);
-static void blkio_reset_stats_cpu(struct blkio_group *blkg)
+void __blkg_release(struct blkio_group *blkg)
{
- struct blkio_group_stats_cpu *stats_cpu;
- int i, j, k;
+ /* release the extra blkcg reference this blkg has been holding */
+ css_put(&blkg->blkcg->css);
+
/*
- * Note: On 64 bit arch this should not be an issue. This has the
- * possibility of returning some inconsistent value on 32bit arch
- * as 64bit update on 32bit is non atomic. Taking care of this
- * corner case makes code very complicated, like sending IPIs to
- * cpus, taking care of stats of offline cpus etc.
+ * A group is freed in rcu manner. But having an rcu lock does not
+ * mean that one can access all the fields of blkg and assume these
+ * are valid. For example, don't try to follow throtl_data and
+ * request queue links.
*
- * reset stats is anyway more of a debug feature and this sounds a
- * corner case. So I am not complicating the code yet until and
- * unless this becomes a real issue.
+ * Having a reference to blkg under an rcu allows acess to only
+ * values local to groups like group stats and group rate limits
*/
- for_each_possible_cpu(i) {
- stats_cpu = per_cpu_ptr(blkg->stats_cpu, i);
- stats_cpu->sectors = 0;
- for(j = 0; j < BLKIO_STAT_CPU_NR; j++)
- for (k = 0; k < BLKIO_STAT_TOTAL; k++)
- stats_cpu->stat_arr_cpu[j][k] = 0;
- }
+ call_rcu(&blkg->rcu_head, blkg_rcu_free);
}
+EXPORT_SYMBOL_GPL(__blkg_release);
static int
blkiocg_reset_stats(struct cgroup *cgroup, struct cftype *cftype, u64 val)
{
- struct blkio_cgroup *blkcg;
+ struct blkio_cgroup *blkcg = cgroup_to_blkio_cgroup(cgroup);
struct blkio_group *blkg;
- struct blkio_group_stats *stats;
struct hlist_node *n;
- uint64_t queued[BLKIO_STAT_TOTAL];
int i;
-#ifdef CONFIG_DEBUG_BLK_CGROUP
- bool idling, waiting, empty;
- unsigned long long now = sched_clock();
-#endif
- blkcg = cgroup_to_blkio_cgroup(cgroup);
+ mutex_lock(&blkcg_pol_mutex);
spin_lock_irq(&blkcg->lock);
- hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node) {
- spin_lock(&blkg->stats_lock);
- stats = &blkg->stats;
-#ifdef CONFIG_DEBUG_BLK_CGROUP
- idling = blkio_blkg_idling(stats);
- waiting = blkio_blkg_waiting(stats);
- empty = blkio_blkg_empty(stats);
-#endif
- for (i = 0; i < BLKIO_STAT_TOTAL; i++)
- queued[i] = stats->stat_arr[BLKIO_STAT_QUEUED][i];
- memset(stats, 0, sizeof(struct blkio_group_stats));
- for (i = 0; i < BLKIO_STAT_TOTAL; i++)
- stats->stat_arr[BLKIO_STAT_QUEUED][i] = queued[i];
-#ifdef CONFIG_DEBUG_BLK_CGROUP
- if (idling) {
- blkio_mark_blkg_idling(stats);
- stats->start_idle_time = now;
- }
- if (waiting) {
- blkio_mark_blkg_waiting(stats);
- stats->start_group_wait_time = now;
- }
- if (empty) {
- blkio_mark_blkg_empty(stats);
- stats->start_empty_time = now;
- }
-#endif
- spin_unlock(&blkg->stats_lock);
-
- /* Reset Per cpu stats which don't take blkg->stats_lock */
- blkio_reset_stats_cpu(blkg);
- }
-
- spin_unlock_irq(&blkcg->lock);
- return 0;
-}
-
-static void blkio_get_key_name(enum stat_sub_type type, dev_t dev, char *str,
- int chars_left, bool diskname_only)
-{
- snprintf(str, chars_left, "%d:%d", MAJOR(dev), MINOR(dev));
- chars_left -= strlen(str);
- if (chars_left <= 0) {
- printk(KERN_WARNING
- "Possibly incorrect cgroup stat display format");
- return;
- }
- if (diskname_only)
- return;
- switch (type) {
- case BLKIO_STAT_READ:
- strlcat(str, " Read", chars_left);
- break;
- case BLKIO_STAT_WRITE:
- strlcat(str, " Write", chars_left);
- break;
- case BLKIO_STAT_SYNC:
- strlcat(str, " Sync", chars_left);
- break;
- case BLKIO_STAT_ASYNC:
- strlcat(str, " Async", chars_left);
- break;
- case BLKIO_STAT_TOTAL:
- strlcat(str, " Total", chars_left);
- break;
- default:
- strlcat(str, " Invalid", chars_left);
- }
-}
-
-static uint64_t blkio_fill_stat(char *str, int chars_left, uint64_t val,
- struct cgroup_map_cb *cb, dev_t dev)
-{
- blkio_get_key_name(0, dev, str, chars_left, true);
- cb->fill(cb, str, val);
- return val;
-}
-
-
-static uint64_t blkio_read_stat_cpu(struct blkio_group *blkg,
- enum stat_type_cpu type, enum stat_sub_type sub_type)
-{
- int cpu;
- struct blkio_group_stats_cpu *stats_cpu;
- u64 val = 0, tval;
-
- for_each_possible_cpu(cpu) {
- unsigned int start;
- stats_cpu = per_cpu_ptr(blkg->stats_cpu, cpu);
-
- do {
- start = u64_stats_fetch_begin(&stats_cpu->syncp);
- if (type == BLKIO_STAT_CPU_SECTORS)
- tval = stats_cpu->sectors;
- else
- tval = stats_cpu->stat_arr_cpu[type][sub_type];
- } while(u64_stats_fetch_retry(&stats_cpu->syncp, start));
-
- val += tval;
- }
-
- return val;
-}
-
-static uint64_t blkio_get_stat_cpu(struct blkio_group *blkg,
- struct cgroup_map_cb *cb, dev_t dev, enum stat_type_cpu type)
-{
- uint64_t disk_total, val;
- char key_str[MAX_KEY_LEN];
- enum stat_sub_type sub_type;
-
- if (type == BLKIO_STAT_CPU_SECTORS) {
- val = blkio_read_stat_cpu(blkg, type, 0);
- return blkio_fill_stat(key_str, MAX_KEY_LEN - 1, val, cb, dev);
- }
-
- for (sub_type = BLKIO_STAT_READ; sub_type < BLKIO_STAT_TOTAL;
- sub_type++) {
- blkio_get_key_name(sub_type, dev, key_str, MAX_KEY_LEN, false);
- val = blkio_read_stat_cpu(blkg, type, sub_type);
- cb->fill(cb, key_str, val);
- }
-
- disk_total = blkio_read_stat_cpu(blkg, type, BLKIO_STAT_READ) +
- blkio_read_stat_cpu(blkg, type, BLKIO_STAT_WRITE);
-
- blkio_get_key_name(BLKIO_STAT_TOTAL, dev, key_str, MAX_KEY_LEN, false);
- cb->fill(cb, key_str, disk_total);
- return disk_total;
-}
-
-/* This should be called with blkg->stats_lock held */
-static uint64_t blkio_get_stat(struct blkio_group *blkg,
- struct cgroup_map_cb *cb, dev_t dev, enum stat_type type)
-{
- uint64_t disk_total;
- char key_str[MAX_KEY_LEN];
- enum stat_sub_type sub_type;
-
- if (type == BLKIO_STAT_TIME)
- return blkio_fill_stat(key_str, MAX_KEY_LEN - 1,
- blkg->stats.time, cb, dev);
-#ifdef CONFIG_DEBUG_BLK_CGROUP
- if (type == BLKIO_STAT_UNACCOUNTED_TIME)
- return blkio_fill_stat(key_str, MAX_KEY_LEN - 1,
- blkg->stats.unaccounted_time, cb, dev);
- if (type == BLKIO_STAT_AVG_QUEUE_SIZE) {
- uint64_t sum = blkg->stats.avg_queue_size_sum;
- uint64_t samples = blkg->stats.avg_queue_size_samples;
- if (samples)
- do_div(sum, samples);
- else
- sum = 0;
- return blkio_fill_stat(key_str, MAX_KEY_LEN - 1, sum, cb, dev);
- }
- if (type == BLKIO_STAT_GROUP_WAIT_TIME)
- return blkio_fill_stat(key_str, MAX_KEY_LEN - 1,
- blkg->stats.group_wait_time, cb, dev);
- if (type == BLKIO_STAT_IDLE_TIME)
- return blkio_fill_stat(key_str, MAX_KEY_LEN - 1,
- blkg->stats.idle_time, cb, dev);
- if (type == BLKIO_STAT_EMPTY_TIME)
- return blkio_fill_stat(key_str, MAX_KEY_LEN - 1,
- blkg->stats.empty_time, cb, dev);
- if (type == BLKIO_STAT_DEQUEUE)
- return blkio_fill_stat(key_str, MAX_KEY_LEN - 1,
- blkg->stats.dequeue, cb, dev);
-#endif
-
- for (sub_type = BLKIO_STAT_READ; sub_type < BLKIO_STAT_TOTAL;
- sub_type++) {
- blkio_get_key_name(sub_type, dev, key_str, MAX_KEY_LEN, false);
- cb->fill(cb, key_str, blkg->stats.stat_arr[type][sub_type]);
- }
- disk_total = blkg->stats.stat_arr[type][BLKIO_STAT_READ] +
- blkg->stats.stat_arr[type][BLKIO_STAT_WRITE];
- blkio_get_key_name(BLKIO_STAT_TOTAL, dev, key_str, MAX_KEY_LEN, false);
- cb->fill(cb, key_str, disk_total);
- return disk_total;
-}
-
-static int blkio_policy_parse_and_set(char *buf,
- struct blkio_policy_node *newpn, enum blkio_policy_id plid, int fileid)
-{
- struct gendisk *disk = NULL;
- char *s[4], *p, *major_s = NULL, *minor_s = NULL;
- unsigned long major, minor;
- int i = 0, ret = -EINVAL;
- int part;
- dev_t dev;
- u64 temp;
-
- memset(s, 0, sizeof(s));
-
- while ((p = strsep(&buf, " ")) != NULL) {
- if (!*p)
- continue;
-
- s[i++] = p;
-
- /* Prevent from inputing too many things */
- if (i == 3)
- break;
- }
-
- if (i != 2)
- goto out;
-
- p = strsep(&s[0], ":");
- if (p != NULL)
- major_s = p;
- else
- goto out;
-
- minor_s = s[0];
- if (!minor_s)
- goto out;
-
- if (strict_strtoul(major_s, 10, &major))
- goto out;
-
- if (strict_strtoul(minor_s, 10, &minor))
- goto out;
-
- dev = MKDEV(major, minor);
-
- if (strict_strtoull(s[1], 10, &temp))
- goto out;
-
- /* For rule removal, do not check for device presence. */
- if (temp) {
- disk = get_gendisk(dev, &part);
- if (!disk || part) {
- ret = -ENODEV;
- goto out;
- }
- }
-
- newpn->dev = dev;
-
- switch (plid) {
- case BLKIO_POLICY_PROP:
- if ((temp < BLKIO_WEIGHT_MIN && temp > 0) ||
- temp > BLKIO_WEIGHT_MAX)
- goto out;
-
- newpn->plid = plid;
- newpn->fileid = fileid;
- newpn->val.weight = temp;
- break;
- case BLKIO_POLICY_THROTL:
- switch(fileid) {
- case BLKIO_THROTL_read_bps_device:
- case BLKIO_THROTL_write_bps_device:
- newpn->plid = plid;
- newpn->fileid = fileid;
- newpn->val.bps = temp;
- break;
- case BLKIO_THROTL_read_iops_device:
- case BLKIO_THROTL_write_iops_device:
- if (temp > THROTL_IOPS_MAX)
- goto out;
-
- newpn->plid = plid;
- newpn->fileid = fileid;
- newpn->val.iops = (unsigned int)temp;
- break;
- }
- break;
- default:
- BUG();
- }
- ret = 0;
-out:
- put_disk(disk);
- return ret;
-}
-
-unsigned int blkcg_get_weight(struct blkio_cgroup *blkcg,
- dev_t dev)
-{
- struct blkio_policy_node *pn;
- unsigned long flags;
- unsigned int weight;
-
- spin_lock_irqsave(&blkcg->lock, flags);
-
- pn = blkio_policy_search_node(blkcg, dev, BLKIO_POLICY_PROP,
- BLKIO_PROP_weight_device);
- if (pn)
- weight = pn->val.weight;
- else
- weight = blkcg->weight;
-
- spin_unlock_irqrestore(&blkcg->lock, flags);
-
- return weight;
-}
-EXPORT_SYMBOL_GPL(blkcg_get_weight);
-
-uint64_t blkcg_get_read_bps(struct blkio_cgroup *blkcg, dev_t dev)
-{
- struct blkio_policy_node *pn;
- unsigned long flags;
- uint64_t bps = -1;
-
- spin_lock_irqsave(&blkcg->lock, flags);
- pn = blkio_policy_search_node(blkcg, dev, BLKIO_POLICY_THROTL,
- BLKIO_THROTL_read_bps_device);
- if (pn)
- bps = pn->val.bps;
- spin_unlock_irqrestore(&blkcg->lock, flags);
-
- return bps;
-}
-
-uint64_t blkcg_get_write_bps(struct blkio_cgroup *blkcg, dev_t dev)
-{
- struct blkio_policy_node *pn;
- unsigned long flags;
- uint64_t bps = -1;
-
- spin_lock_irqsave(&blkcg->lock, flags);
- pn = blkio_policy_search_node(blkcg, dev, BLKIO_POLICY_THROTL,
- BLKIO_THROTL_write_bps_device);
- if (pn)
- bps = pn->val.bps;
- spin_unlock_irqrestore(&blkcg->lock, flags);
-
- return bps;
-}
-unsigned int blkcg_get_read_iops(struct blkio_cgroup *blkcg, dev_t dev)
-{
- struct blkio_policy_node *pn;
- unsigned long flags;
- unsigned int iops = -1;
-
- spin_lock_irqsave(&blkcg->lock, flags);
- pn = blkio_policy_search_node(blkcg, dev, BLKIO_POLICY_THROTL,
- BLKIO_THROTL_read_iops_device);
- if (pn)
- iops = pn->val.iops;
- spin_unlock_irqrestore(&blkcg->lock, flags);
-
- return iops;
-}
-
-unsigned int blkcg_get_write_iops(struct blkio_cgroup *blkcg, dev_t dev)
-{
- struct blkio_policy_node *pn;
- unsigned long flags;
- unsigned int iops = -1;
-
- spin_lock_irqsave(&blkcg->lock, flags);
- pn = blkio_policy_search_node(blkcg, dev, BLKIO_POLICY_THROTL,
- BLKIO_THROTL_write_iops_device);
- if (pn)
- iops = pn->val.iops;
- spin_unlock_irqrestore(&blkcg->lock, flags);
-
- return iops;
-}
+ /*
+ * Note that stat reset is racy - it doesn't synchronize against
+ * stat updates. This is a debug feature which shouldn't exist
+ * anyway. If you get hit by a race, retry.
+ */
+ hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node) {
+ for (i = 0; i < BLKCG_MAX_POLS; i++) {
+ struct blkio_policy_type *pol = blkio_policy[i];
-/* Checks whether user asked for deleting a policy rule */
-static bool blkio_delete_rule_command(struct blkio_policy_node *pn)
-{
- switch(pn->plid) {
- case BLKIO_POLICY_PROP:
- if (pn->val.weight == 0)
- return 1;
- break;
- case BLKIO_POLICY_THROTL:
- switch(pn->fileid) {
- case BLKIO_THROTL_read_bps_device:
- case BLKIO_THROTL_write_bps_device:
- if (pn->val.bps == 0)
- return 1;
- break;
- case BLKIO_THROTL_read_iops_device:
- case BLKIO_THROTL_write_iops_device:
- if (pn->val.iops == 0)
- return 1;
+ if (blkcg_policy_enabled(blkg->q, pol) &&
+ pol->ops.blkio_reset_group_stats_fn)
+ pol->ops.blkio_reset_group_stats_fn(blkg);
}
- break;
- default:
- BUG();
}
+ spin_unlock_irq(&blkcg->lock);
+ mutex_unlock(&blkcg_pol_mutex);
return 0;
}
-static void blkio_update_policy_rule(struct blkio_policy_node *oldpn,
- struct blkio_policy_node *newpn)
-{
- switch(oldpn->plid) {
- case BLKIO_POLICY_PROP:
- oldpn->val.weight = newpn->val.weight;
- break;
- case BLKIO_POLICY_THROTL:
- switch(newpn->fileid) {
- case BLKIO_THROTL_read_bps_device:
- case BLKIO_THROTL_write_bps_device:
- oldpn->val.bps = newpn->val.bps;
- break;
- case BLKIO_THROTL_read_iops_device:
- case BLKIO_THROTL_write_iops_device:
- oldpn->val.iops = newpn->val.iops;
- }
- break;
- default:
- BUG();
- }
-}
-
-/*
- * Some rules/values in blkg have changed. Propagate those to respective
- * policies.
- */
-static void blkio_update_blkg_policy(struct blkio_cgroup *blkcg,
- struct blkio_group *blkg, struct blkio_policy_node *pn)
+static const char *blkg_dev_name(struct blkio_group *blkg)
{
- unsigned int weight, iops;
- u64 bps;
-
- switch(pn->plid) {
- case BLKIO_POLICY_PROP:
- weight = pn->val.weight ? pn->val.weight :
- blkcg->weight;
- blkio_update_group_weight(blkg, weight);
- break;
- case BLKIO_POLICY_THROTL:
- switch(pn->fileid) {
- case BLKIO_THROTL_read_bps_device:
- case BLKIO_THROTL_write_bps_device:
- bps = pn->val.bps ? pn->val.bps : (-1);
- blkio_update_group_bps(blkg, bps, pn->fileid);
- break;
- case BLKIO_THROTL_read_iops_device:
- case BLKIO_THROTL_write_iops_device:
- iops = pn->val.iops ? pn->val.iops : (-1);
- blkio_update_group_iops(blkg, iops, pn->fileid);
- break;
- }
- break;
- default:
- BUG();
- }
+ /* some drivers (floppy) instantiate a queue w/o disk registered */
+ if (blkg->q->backing_dev_info.dev)
+ return dev_name(blkg->q->backing_dev_info.dev);
+ return NULL;
}
-/*
- * A policy node rule has been updated. Propagate this update to all the
- * block groups which might be affected by this update.
+/**
+ * blkcg_print_blkgs - helper for printing per-blkg data
+ * @sf: seq_file to print to
+ * @blkcg: blkcg of interest
+ * @prfill: fill function to print out a blkg
+ * @pol: policy in question
+ * @data: data to be passed to @prfill
+ * @show_total: to print out sum of prfill return values or not
+ *
+ * This function invokes @prfill on each blkg of @blkcg if pd for the
+ * policy specified by @pol exists. @prfill is invoked with @sf, the
+ * policy data and @data. If @show_total is %true, the sum of the return
+ * values from @prfill is printed with "Total" label at the end.
+ *
+ * This is to be used to construct print functions for
+ * cftype->read_seq_string method.
*/
-static void blkio_update_policy_node_blkg(struct blkio_cgroup *blkcg,
- struct blkio_policy_node *pn)
+void blkcg_print_blkgs(struct seq_file *sf, struct blkio_cgroup *blkcg,
+ u64 (*prfill)(struct seq_file *, void *, int),
+ const struct blkio_policy_type *pol, int data,
+ bool show_total)
{
struct blkio_group *blkg;
struct hlist_node *n;
+ u64 total = 0;
- spin_lock(&blkio_list_lock);
spin_lock_irq(&blkcg->lock);
-
- hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node) {
- if (pn->dev != blkg->dev || pn->plid != blkg->plid)
- continue;
- blkio_update_blkg_policy(blkcg, blkg, pn);
- }
-
+ hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node)
+ if (blkcg_policy_enabled(blkg->q, pol))
+ total += prfill(sf, blkg->pd[pol->plid]->pdata, data);
spin_unlock_irq(&blkcg->lock);
- spin_unlock(&blkio_list_lock);
+
+ if (show_total)
+ seq_printf(sf, "Total %llu\n", (unsigned long long)total);
}
+EXPORT_SYMBOL_GPL(blkcg_print_blkgs);
-static int blkiocg_file_write(struct cgroup *cgrp, struct cftype *cft,
- const char *buffer)
+/**
+ * __blkg_prfill_u64 - prfill helper for a single u64 value
+ * @sf: seq_file to print to
+ * @pdata: policy private data of interest
+ * @v: value to print
+ *
+ * Print @v to @sf for the device assocaited with @pdata.
+ */
+u64 __blkg_prfill_u64(struct seq_file *sf, void *pdata, u64 v)
{
- int ret = 0;
- char *buf;
- struct blkio_policy_node *newpn, *pn;
- struct blkio_cgroup *blkcg;
- int keep_newpn = 0;
- enum blkio_policy_id plid = BLKIOFILE_POLICY(cft->private);
- int fileid = BLKIOFILE_ATTR(cft->private);
-
- buf = kstrdup(buffer, GFP_KERNEL);
- if (!buf)
- return -ENOMEM;
-
- newpn = kzalloc(sizeof(*newpn), GFP_KERNEL);
- if (!newpn) {
- ret = -ENOMEM;
- goto free_buf;
- }
-
- ret = blkio_policy_parse_and_set(buf, newpn, plid, fileid);
- if (ret)
- goto free_newpn;
-
- blkcg = cgroup_to_blkio_cgroup(cgrp);
-
- spin_lock_irq(&blkcg->lock);
-
- pn = blkio_policy_search_node(blkcg, newpn->dev, plid, fileid);
- if (!pn) {
- if (!blkio_delete_rule_command(newpn)) {
- blkio_policy_insert_node(blkcg, newpn);
- keep_newpn = 1;
- }
- spin_unlock_irq(&blkcg->lock);
- goto update_io_group;
- }
-
- if (blkio_delete_rule_command(newpn)) {
- blkio_policy_delete_node(pn);
- kfree(pn);
- spin_unlock_irq(&blkcg->lock);
- goto update_io_group;
- }
- spin_unlock_irq(&blkcg->lock);
-
- blkio_update_policy_rule(pn, newpn);
+ const char *dname = blkg_dev_name(pdata_to_blkg(pdata));
-update_io_group:
- blkio_update_policy_node_blkg(blkcg, newpn);
+ if (!dname)
+ return 0;
-free_newpn:
- if (!keep_newpn)
- kfree(newpn);
-free_buf:
- kfree(buf);
- return ret;
+ seq_printf(sf, "%s %llu\n", dname, (unsigned long long)v);
+ return v;
}
+EXPORT_SYMBOL_GPL(__blkg_prfill_u64);
-static void
-blkio_print_policy_node(struct seq_file *m, struct blkio_policy_node *pn)
-{
- switch(pn->plid) {
- case BLKIO_POLICY_PROP:
- if (pn->fileid == BLKIO_PROP_weight_device)
- seq_printf(m, "%u:%u\t%u\n", MAJOR(pn->dev),
- MINOR(pn->dev), pn->val.weight);
- break;
- case BLKIO_POLICY_THROTL:
- switch(pn->fileid) {
- case BLKIO_THROTL_read_bps_device:
- case BLKIO_THROTL_write_bps_device:
- seq_printf(m, "%u:%u\t%llu\n", MAJOR(pn->dev),
- MINOR(pn->dev), pn->val.bps);
- break;
- case BLKIO_THROTL_read_iops_device:
- case BLKIO_THROTL_write_iops_device:
- seq_printf(m, "%u:%u\t%u\n", MAJOR(pn->dev),
- MINOR(pn->dev), pn->val.iops);
- break;
- }
- break;
- default:
- BUG();
- }
-}
+/**
+ * __blkg_prfill_rwstat - prfill helper for a blkg_rwstat
+ * @sf: seq_file to print to
+ * @pdata: policy private data of interest
+ * @rwstat: rwstat to print
+ *
+ * Print @rwstat to @sf for the device assocaited with @pdata.
+ */
+u64 __blkg_prfill_rwstat(struct seq_file *sf, void *pdata,
+ const struct blkg_rwstat *rwstat)
+{
+ static const char *rwstr[] = {
+ [BLKG_RWSTAT_READ] = "Read",
+ [BLKG_RWSTAT_WRITE] = "Write",
+ [BLKG_RWSTAT_SYNC] = "Sync",
+ [BLKG_RWSTAT_ASYNC] = "Async",
+ };
+ const char *dname = blkg_dev_name(pdata_to_blkg(pdata));
+ u64 v;
+ int i;
-/* cgroup files which read their data from policy nodes end up here */
-static void blkio_read_policy_node_files(struct cftype *cft,
- struct blkio_cgroup *blkcg, struct seq_file *m)
-{
- struct blkio_policy_node *pn;
-
- if (!list_empty(&blkcg->policy_list)) {
- spin_lock_irq(&blkcg->lock);
- list_for_each_entry(pn, &blkcg->policy_list, node) {
- if (!pn_matches_cftype(cft, pn))
- continue;
- blkio_print_policy_node(m, pn);
- }
- spin_unlock_irq(&blkcg->lock);
- }
-}
+ if (!dname)
+ return 0;
-static int blkiocg_file_read(struct cgroup *cgrp, struct cftype *cft,
- struct seq_file *m)
-{
- struct blkio_cgroup *blkcg;
- enum blkio_policy_id plid = BLKIOFILE_POLICY(cft->private);
- int name = BLKIOFILE_ATTR(cft->private);
-
- blkcg = cgroup_to_blkio_cgroup(cgrp);
-
- switch(plid) {
- case BLKIO_POLICY_PROP:
- switch(name) {
- case BLKIO_PROP_weight_device:
- blkio_read_policy_node_files(cft, blkcg, m);
- return 0;
- default:
- BUG();
- }
- break;
- case BLKIO_POLICY_THROTL:
- switch(name){
- case BLKIO_THROTL_read_bps_device:
- case BLKIO_THROTL_write_bps_device:
- case BLKIO_THROTL_read_iops_device:
- case BLKIO_THROTL_write_iops_device:
- blkio_read_policy_node_files(cft, blkcg, m);
- return 0;
- default:
- BUG();
- }
- break;
- default:
- BUG();
- }
+ for (i = 0; i < BLKG_RWSTAT_NR; i++)
+ seq_printf(sf, "%s %s %llu\n", dname, rwstr[i],
+ (unsigned long long)rwstat->cnt[i]);
- return 0;
+ v = rwstat->cnt[BLKG_RWSTAT_READ] + rwstat->cnt[BLKG_RWSTAT_WRITE];
+ seq_printf(sf, "%s Total %llu\n", dname, (unsigned long long)v);
+ return v;
}
-static int blkio_read_blkg_stats(struct blkio_cgroup *blkcg,
- struct cftype *cft, struct cgroup_map_cb *cb,
- enum stat_type type, bool show_total, bool pcpu)
+/**
+ * blkg_prfill_stat - prfill callback for blkg_stat
+ * @sf: seq_file to print to
+ * @pdata: policy private data of interest
+ * @off: offset to the blkg_stat in @pdata
+ *
+ * prfill callback for printing a blkg_stat.
+ */
+u64 blkg_prfill_stat(struct seq_file *sf, void *pdata, int off)
{
- struct blkio_group *blkg;
- struct hlist_node *n;
- uint64_t cgroup_total = 0;
-
- rcu_read_lock();
- hlist_for_each_entry_rcu(blkg, n, &blkcg->blkg_list, blkcg_node) {
- if (blkg->dev) {
- if (!cftype_blkg_same_policy(cft, blkg))
- continue;
- if (pcpu)
- cgroup_total += blkio_get_stat_cpu(blkg, cb,
- blkg->dev, type);
- else {
- spin_lock_irq(&blkg->stats_lock);
- cgroup_total += blkio_get_stat(blkg, cb,
- blkg->dev, type);
- spin_unlock_irq(&blkg->stats_lock);
- }
- }
- }
- if (show_total)
- cb->fill(cb, "Total", cgroup_total);
- rcu_read_unlock();
- return 0;
+ return __blkg_prfill_u64(sf, pdata, blkg_stat_read(pdata + off));
}
+EXPORT_SYMBOL_GPL(blkg_prfill_stat);
-/* All map kind of cgroup file get serviced by this function */
-static int blkiocg_file_read_map(struct cgroup *cgrp, struct cftype *cft,
- struct cgroup_map_cb *cb)
+/**
+ * blkg_prfill_rwstat - prfill callback for blkg_rwstat
+ * @sf: seq_file to print to
+ * @pdata: policy private data of interest
+ * @off: offset to the blkg_rwstat in @pdata
+ *
+ * prfill callback for printing a blkg_rwstat.
+ */
+u64 blkg_prfill_rwstat(struct seq_file *sf, void *pdata, int off)
{
- struct blkio_cgroup *blkcg;
- enum blkio_policy_id plid = BLKIOFILE_POLICY(cft->private);
- int name = BLKIOFILE_ATTR(cft->private);
-
- blkcg = cgroup_to_blkio_cgroup(cgrp);
-
- switch(plid) {
- case BLKIO_POLICY_PROP:
- switch(name) {
- case BLKIO_PROP_time:
- return blkio_read_blkg_stats(blkcg, cft, cb,
- BLKIO_STAT_TIME, 0, 0);
- case BLKIO_PROP_sectors:
- return blkio_read_blkg_stats(blkcg, cft, cb,
- BLKIO_STAT_CPU_SECTORS, 0, 1);
- case BLKIO_PROP_io_service_bytes:
- return blkio_read_blkg_stats(blkcg, cft, cb,
- BLKIO_STAT_CPU_SERVICE_BYTES, 1, 1);
- case BLKIO_PROP_io_serviced:
- return blkio_read_blkg_stats(blkcg, cft, cb,
- BLKIO_STAT_CPU_SERVICED, 1, 1);
- case BLKIO_PROP_io_service_time:
- return blkio_read_blkg_stats(blkcg, cft, cb,
- BLKIO_STAT_SERVICE_TIME, 1, 0);
- case BLKIO_PROP_io_wait_time:
- return blkio_read_blkg_stats(blkcg, cft, cb,
- BLKIO_STAT_WAIT_TIME, 1, 0);
- case BLKIO_PROP_io_merged:
- return blkio_read_blkg_stats(blkcg, cft, cb,
- BLKIO_STAT_CPU_MERGED, 1, 1);
- case BLKIO_PROP_io_queued:
- return blkio_read_blkg_stats(blkcg, cft, cb,
- BLKIO_STAT_QUEUED, 1, 0);
-#ifdef CONFIG_DEBUG_BLK_CGROUP
- case BLKIO_PROP_unaccounted_time:
- return blkio_read_blkg_stats(blkcg, cft, cb,
- BLKIO_STAT_UNACCOUNTED_TIME, 0, 0);
- case BLKIO_PROP_dequeue:
- return blkio_read_blkg_stats(blkcg, cft, cb,
- BLKIO_STAT_DEQUEUE, 0, 0);
- case BLKIO_PROP_avg_queue_size:
- return blkio_read_blkg_stats(blkcg, cft, cb,
- BLKIO_STAT_AVG_QUEUE_SIZE, 0, 0);
- case BLKIO_PROP_group_wait_time:
- return blkio_read_blkg_stats(blkcg, cft, cb,
- BLKIO_STAT_GROUP_WAIT_TIME, 0, 0);
- case BLKIO_PROP_idle_time:
- return blkio_read_blkg_stats(blkcg, cft, cb,
- BLKIO_STAT_IDLE_TIME, 0, 0);
- case BLKIO_PROP_empty_time:
- return blkio_read_blkg_stats(blkcg, cft, cb,
- BLKIO_STAT_EMPTY_TIME, 0, 0);
-#endif
- default:
- BUG();
- }
- break;
- case BLKIO_POLICY_THROTL:
- switch(name){
- case BLKIO_THROTL_io_service_bytes:
- return blkio_read_blkg_stats(blkcg, cft, cb,
- BLKIO_STAT_CPU_SERVICE_BYTES, 1, 1);
- case BLKIO_THROTL_io_serviced:
- return blkio_read_blkg_stats(blkcg, cft, cb,
- BLKIO_STAT_CPU_SERVICED, 1, 1);
- default:
- BUG();
- }
- break;
- default:
- BUG();
- }
+ struct blkg_rwstat rwstat = blkg_rwstat_read(pdata + off);
- return 0;
+ return __blkg_prfill_rwstat(sf, pdata, &rwstat);
}
+EXPORT_SYMBOL_GPL(blkg_prfill_rwstat);
-static int blkio_weight_write(struct blkio_cgroup *blkcg, u64 val)
+/**
+ * blkg_conf_prep - parse and prepare for per-blkg config update
+ * @blkcg: target block cgroup
+ * @pol: target policy
+ * @input: input string
+ * @ctx: blkg_conf_ctx to be filled
+ *
+ * Parse per-blkg config update from @input and initialize @ctx with the
+ * result. @ctx->blkg points to the blkg to be updated and @ctx->v the new
+ * value. This function returns with RCU read lock and queue lock held and
+ * must be paired with blkg_conf_finish().
+ */
+int blkg_conf_prep(struct blkio_cgroup *blkcg,
+ const struct blkio_policy_type *pol, const char *input,
+ struct blkg_conf_ctx *ctx)
+ __acquires(rcu) __acquires(disk->queue->queue_lock)
{
+ struct gendisk *disk;
struct blkio_group *blkg;
- struct hlist_node *n;
- struct blkio_policy_node *pn;
+ unsigned int major, minor;
+ unsigned long long v;
+ int part, ret;
- if (val < BLKIO_WEIGHT_MIN || val > BLKIO_WEIGHT_MAX)
+ if (sscanf(input, "%u:%u %llu", &major, &minor, &v) != 3)
return -EINVAL;
- spin_lock(&blkio_list_lock);
- spin_lock_irq(&blkcg->lock);
- blkcg->weight = (unsigned int)val;
-
- hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node) {
- pn = blkio_policy_search_node(blkcg, blkg->dev,
- BLKIO_POLICY_PROP, BLKIO_PROP_weight_device);
- if (pn)
- continue;
-
- blkio_update_group_weight(blkg, blkcg->weight);
- }
- spin_unlock_irq(&blkcg->lock);
- spin_unlock(&blkio_list_lock);
- return 0;
-}
+ disk = get_gendisk(MKDEV(major, minor), &part);
+ if (!disk || part)
+ return -EINVAL;
-static u64 blkiocg_file_read_u64 (struct cgroup *cgrp, struct cftype *cft) {
- struct blkio_cgroup *blkcg;
- enum blkio_policy_id plid = BLKIOFILE_POLICY(cft->private);
- int name = BLKIOFILE_ATTR(cft->private);
+ rcu_read_lock();
+ spin_lock_irq(disk->queue->queue_lock);
- blkcg = cgroup_to_blkio_cgroup(cgrp);
+ if (blkcg_policy_enabled(disk->queue, pol))
+ blkg = blkg_lookup_create(blkcg, disk->queue);
+ else
+ blkg = ERR_PTR(-EINVAL);
- switch(plid) {
- case BLKIO_POLICY_PROP:
- switch(name) {
- case BLKIO_PROP_weight:
- return (u64)blkcg->weight;
+ if (IS_ERR(blkg)) {
+ ret = PTR_ERR(blkg);
+ rcu_read_unlock();
+ spin_unlock_irq(disk->queue->queue_lock);
+ put_disk(disk);
+ /*
+ * If queue was bypassing, we should retry. Do so after a
+ * short msleep(). It isn't strictly necessary but queue
+ * can be bypassing for some time and it's always nice to
+ * avoid busy looping.
+ */
+ if (ret == -EBUSY) {
+ msleep(10);
+ ret = restart_syscall();
}
- break;
- default:
- BUG();
+ return ret;
}
+
+ ctx->disk = disk;
+ ctx->blkg = blkg;
+ ctx->v = v;
return 0;
}
+EXPORT_SYMBOL_GPL(blkg_conf_prep);
-static int
-blkiocg_file_write_u64(struct cgroup *cgrp, struct cftype *cft, u64 val)
+/**
+ * blkg_conf_finish - finish up per-blkg config update
+ * @ctx: blkg_conf_ctx intiailized by blkg_conf_prep()
+ *
+ * Finish up after per-blkg config update. This function must be paired
+ * with blkg_conf_prep().
+ */
+void blkg_conf_finish(struct blkg_conf_ctx *ctx)
+ __releases(ctx->disk->queue->queue_lock) __releases(rcu)
{
- struct blkio_cgroup *blkcg;
- enum blkio_policy_id plid = BLKIOFILE_POLICY(cft->private);
- int name = BLKIOFILE_ATTR(cft->private);
-
- blkcg = cgroup_to_blkio_cgroup(cgrp);
-
- switch(plid) {
- case BLKIO_POLICY_PROP:
- switch(name) {
- case BLKIO_PROP_weight:
- return blkio_weight_write(blkcg, val);
- }
- break;
- default:
- BUG();
- }
-
- return 0;
+ spin_unlock_irq(ctx->disk->queue->queue_lock);
+ rcu_read_unlock();
+ put_disk(ctx->disk);
}
+EXPORT_SYMBOL_GPL(blkg_conf_finish);
struct cftype blkio_files[] = {
- {
- .name = "weight_device",
- .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
- BLKIO_PROP_weight_device),
- .read_seq_string = blkiocg_file_read,
- .write_string = blkiocg_file_write,
- .max_write_len = 256,
- },
- {
- .name = "weight",
- .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
- BLKIO_PROP_weight),
- .read_u64 = blkiocg_file_read_u64,
- .write_u64 = blkiocg_file_write_u64,
- },
- {
- .name = "time",
- .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
- BLKIO_PROP_time),
- .read_map = blkiocg_file_read_map,
- },
- {
- .name = "sectors",
- .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
- BLKIO_PROP_sectors),
- .read_map = blkiocg_file_read_map,
- },
- {
- .name = "io_service_bytes",
- .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
- BLKIO_PROP_io_service_bytes),
- .read_map = blkiocg_file_read_map,
- },
- {
- .name = "io_serviced",
- .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
- BLKIO_PROP_io_serviced),
- .read_map = blkiocg_file_read_map,
- },
- {
- .name = "io_service_time",
- .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
- BLKIO_PROP_io_service_time),
- .read_map = blkiocg_file_read_map,
- },
- {
- .name = "io_wait_time",
- .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
- BLKIO_PROP_io_wait_time),
- .read_map = blkiocg_file_read_map,
- },
- {
- .name = "io_merged",
- .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
- BLKIO_PROP_io_merged),
- .read_map = blkiocg_file_read_map,
- },
- {
- .name = "io_queued",
- .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
- BLKIO_PROP_io_queued),
- .read_map = blkiocg_file_read_map,
- },
{
.name = "reset_stats",
.write_u64 = blkiocg_reset_stats,
},
-#ifdef CONFIG_BLK_DEV_THROTTLING
- {
- .name = "throttle.read_bps_device",
- .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_THROTL,
- BLKIO_THROTL_read_bps_device),
- .read_seq_string = blkiocg_file_read,
- .write_string = blkiocg_file_write,
- .max_write_len = 256,
- },
-
- {
- .name = "throttle.write_bps_device",
- .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_THROTL,
- BLKIO_THROTL_write_bps_device),
- .read_seq_string = blkiocg_file_read,
- .write_string = blkiocg_file_write,
- .max_write_len = 256,
- },
-
- {
- .name = "throttle.read_iops_device",
- .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_THROTL,
- BLKIO_THROTL_read_iops_device),
- .read_seq_string = blkiocg_file_read,
- .write_string = blkiocg_file_write,
- .max_write_len = 256,
- },
-
- {
- .name = "throttle.write_iops_device",
- .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_THROTL,
- BLKIO_THROTL_write_iops_device),
- .read_seq_string = blkiocg_file_read,
- .write_string = blkiocg_file_write,
- .max_write_len = 256,
- },
- {
- .name = "throttle.io_service_bytes",
- .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_THROTL,
- BLKIO_THROTL_io_service_bytes),
- .read_map = blkiocg_file_read_map,
- },
- {
- .name = "throttle.io_serviced",
- .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_THROTL,
- BLKIO_THROTL_io_serviced),
- .read_map = blkiocg_file_read_map,
- },
-#endif /* CONFIG_BLK_DEV_THROTTLING */
-
-#ifdef CONFIG_DEBUG_BLK_CGROUP
- {
- .name = "avg_queue_size",
- .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
- BLKIO_PROP_avg_queue_size),
- .read_map = blkiocg_file_read_map,
- },
- {
- .name = "group_wait_time",
- .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
- BLKIO_PROP_group_wait_time),
- .read_map = blkiocg_file_read_map,
- },
- {
- .name = "idle_time",
- .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
- BLKIO_PROP_idle_time),
- .read_map = blkiocg_file_read_map,
- },
- {
- .name = "empty_time",
- .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
- BLKIO_PROP_empty_time),
- .read_map = blkiocg_file_read_map,
- },
- {
- .name = "dequeue",
- .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
- BLKIO_PROP_dequeue),
- .read_map = blkiocg_file_read_map,
- },
- {
- .name = "unaccounted_time",
- .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
- BLKIO_PROP_unaccounted_time),
- .read_map = blkiocg_file_read_map,
- },
-#endif
+ { } /* terminate */
};
-static int blkiocg_populate(struct cgroup_subsys *subsys, struct cgroup *cgroup)
-{
- return cgroup_add_files(cgroup, subsys, blkio_files,
- ARRAY_SIZE(blkio_files));
-}
-
-static void blkiocg_destroy(struct cgroup *cgroup)
+/**
+ * blkiocg_pre_destroy - cgroup pre_destroy callback
+ * @cgroup: cgroup of interest
+ *
+ * This function is called when @cgroup is about to go away and responsible
+ * for shooting down all blkgs associated with @cgroup. blkgs should be
+ * removed while holding both q and blkcg locks. As blkcg lock is nested
+ * inside q lock, this function performs reverse double lock dancing.
+ *
+ * This is the blkcg counterpart of ioc_release_fn().
+ */
+static int blkiocg_pre_destroy(struct cgroup *cgroup)
{
struct blkio_cgroup *blkcg = cgroup_to_blkio_cgroup(cgroup);
- unsigned long flags;
- struct blkio_group *blkg;
- void *key;
- struct blkio_policy_type *blkiop;
- struct blkio_policy_node *pn, *pntmp;
- rcu_read_lock();
- do {
- spin_lock_irqsave(&blkcg->lock, flags);
+ spin_lock_irq(&blkcg->lock);
- if (hlist_empty(&blkcg->blkg_list)) {
- spin_unlock_irqrestore(&blkcg->lock, flags);
- break;
+ while (!hlist_empty(&blkcg->blkg_list)) {
+ struct blkio_group *blkg = hlist_entry(blkcg->blkg_list.first,
+ struct blkio_group, blkcg_node);
+ struct request_queue *q = blkg->q;
+
+ if (spin_trylock(q->queue_lock)) {
+ blkg_destroy(blkg);
+ spin_unlock(q->queue_lock);
+ } else {
+ spin_unlock_irq(&blkcg->lock);
+ cpu_relax();
+ spin_lock_irq(&blkcg->lock);
}
+ }
- blkg = hlist_entry(blkcg->blkg_list.first, struct blkio_group,
- blkcg_node);
- key = rcu_dereference(blkg->key);
- __blkiocg_del_blkio_group(blkg);
-
- spin_unlock_irqrestore(&blkcg->lock, flags);
-
- /*
- * This blkio_group is being unlinked as associated cgroup is
- * going away. Let all the IO controlling policies know about
- * this event.
- */
- spin_lock(&blkio_list_lock);
- list_for_each_entry(blkiop, &blkio_list, list) {
- if (blkiop->plid != blkg->plid)
- continue;
- blkiop->ops.blkio_unlink_group_fn(key, blkg);
- }
- spin_unlock(&blkio_list_lock);
- } while (1);
+ spin_unlock_irq(&blkcg->lock);
+ return 0;
+}
- list_for_each_entry_safe(pn, pntmp, &blkcg->policy_list, node) {
- blkio_policy_delete_node(pn);
- kfree(pn);
- }
+static void blkiocg_destroy(struct cgroup *cgroup)
+{
+ struct blkio_cgroup *blkcg = cgroup_to_blkio_cgroup(cgroup);
- free_css_id(&blkio_subsys, &blkcg->css);
- rcu_read_unlock();
if (blkcg != &blkio_root_cgroup)
kfree(blkcg);
}
static struct cgroup_subsys_state *blkiocg_create(struct cgroup *cgroup)
{
+ static atomic64_t id_seq = ATOMIC64_INIT(0);
struct blkio_cgroup *blkcg;
struct cgroup *parent = cgroup->parent;
if (!blkcg)
return ERR_PTR(-ENOMEM);
- blkcg->weight = BLKIO_WEIGHT_DEFAULT;
+ blkcg->cfq_weight = CFQ_WEIGHT_DEFAULT;
+ blkcg->id = atomic64_inc_return(&id_seq); /* root is 0, start from 1 */
done:
spin_lock_init(&blkcg->lock);
INIT_HLIST_HEAD(&blkcg->blkg_list);
- INIT_LIST_HEAD(&blkcg->policy_list);
return &blkcg->css;
}
+/**
+ * blkcg_init_queue - initialize blkcg part of request queue
+ * @q: request_queue to initialize
+ *
+ * Called from blk_alloc_queue_node(). Responsible for initializing blkcg
+ * part of new request_queue @q.
+ *
+ * RETURNS:
+ * 0 on success, -errno on failure.
+ */
+int blkcg_init_queue(struct request_queue *q)
+{
+ might_sleep();
+
+ return blk_throtl_init(q);
+}
+
+/**
+ * blkcg_drain_queue - drain blkcg part of request_queue
+ * @q: request_queue to drain
+ *
+ * Called from blk_drain_queue(). Responsible for draining blkcg part.
+ */
+void blkcg_drain_queue(struct request_queue *q)
+{
+ lockdep_assert_held(q->queue_lock);
+
+ blk_throtl_drain(q);
+}
+
+/**
+ * blkcg_exit_queue - exit and release blkcg part of request_queue
+ * @q: request_queue being released
+ *
+ * Called from blk_release_queue(). Responsible for exiting blkcg part.
+ */
+void blkcg_exit_queue(struct request_queue *q)
+{
+ spin_lock_irq(q->queue_lock);
+ blkg_destroy_all(q);
+ spin_unlock_irq(q->queue_lock);
+
+ blk_throtl_exit(q);
+}
+
/*
* We cannot support shared io contexts, as we have no mean to support
* two tasks with the same ioc in two different groups without major rework
return ret;
}
-static void blkiocg_attach(struct cgroup *cgrp, struct cgroup_taskset *tset)
-{
- struct task_struct *task;
- struct io_context *ioc;
-
- cgroup_taskset_for_each(task, cgrp, tset) {
- /* we don't lose anything even if ioc allocation fails */
- ioc = get_task_io_context(task, GFP_ATOMIC, NUMA_NO_NODE);
- if (ioc) {
- ioc_cgroup_changed(ioc);
- put_io_context(ioc);
- }
- }
-}
-
struct cgroup_subsys blkio_subsys = {
.name = "blkio",
.create = blkiocg_create,
.can_attach = blkiocg_can_attach,
- .attach = blkiocg_attach,
+ .pre_destroy = blkiocg_pre_destroy,
.destroy = blkiocg_destroy,
- .populate = blkiocg_populate,
-#ifdef CONFIG_BLK_CGROUP
- /* note: blkio_subsys_id is otherwise defined in blk-cgroup.h */
.subsys_id = blkio_subsys_id,
-#endif
- .use_id = 1,
+ .base_cftypes = blkio_files,
.module = THIS_MODULE,
};
EXPORT_SYMBOL_GPL(blkio_subsys);
-void blkio_policy_register(struct blkio_policy_type *blkiop)
+/**
+ * blkcg_activate_policy - activate a blkcg policy on a request_queue
+ * @q: request_queue of interest
+ * @pol: blkcg policy to activate
+ *
+ * Activate @pol on @q. Requires %GFP_KERNEL context. @q goes through
+ * bypass mode to populate its blkgs with policy_data for @pol.
+ *
+ * Activation happens with @q bypassed, so nobody would be accessing blkgs
+ * from IO path. Update of each blkg is protected by both queue and blkcg
+ * locks so that holding either lock and testing blkcg_policy_enabled() is
+ * always enough for dereferencing policy data.
+ *
+ * The caller is responsible for synchronizing [de]activations and policy
+ * [un]registerations. Returns 0 on success, -errno on failure.
+ */
+int blkcg_activate_policy(struct request_queue *q,
+ const struct blkio_policy_type *pol)
{
- spin_lock(&blkio_list_lock);
- list_add_tail(&blkiop->list, &blkio_list);
- spin_unlock(&blkio_list_lock);
+ LIST_HEAD(pds);
+ struct blkio_group *blkg;
+ struct blkg_policy_data *pd, *n;
+ int cnt = 0, ret;
+
+ if (blkcg_policy_enabled(q, pol))
+ return 0;
+
+ blk_queue_bypass_start(q);
+
+ /* make sure the root blkg exists and count the existing blkgs */
+ spin_lock_irq(q->queue_lock);
+
+ rcu_read_lock();
+ blkg = __blkg_lookup_create(&blkio_root_cgroup, q);
+ rcu_read_unlock();
+
+ if (IS_ERR(blkg)) {
+ ret = PTR_ERR(blkg);
+ goto out_unlock;
+ }
+ q->root_blkg = blkg;
+
+ list_for_each_entry(blkg, &q->blkg_list, q_node)
+ cnt++;
+
+ spin_unlock_irq(q->queue_lock);
+
+ /* allocate policy_data for all existing blkgs */
+ while (cnt--) {
+ pd = kzalloc_node(blkg_pd_size(pol), GFP_KERNEL, q->node);
+ if (!pd) {
+ ret = -ENOMEM;
+ goto out_free;
+ }
+ list_add_tail(&pd->alloc_node, &pds);
+ }
+
+ /*
+ * Install the allocated pds. With @q bypassing, no new blkg
+ * should have been created while the queue lock was dropped.
+ */
+ spin_lock_irq(q->queue_lock);
+
+ list_for_each_entry(blkg, &q->blkg_list, q_node) {
+ if (WARN_ON(list_empty(&pds))) {
+ /* umm... this shouldn't happen, just abort */
+ ret = -ENOMEM;
+ goto out_unlock;
+ }
+ pd = list_first_entry(&pds, struct blkg_policy_data, alloc_node);
+ list_del_init(&pd->alloc_node);
+
+ /* grab blkcg lock too while installing @pd on @blkg */
+ spin_lock(&blkg->blkcg->lock);
+
+ blkg->pd[pol->plid] = pd;
+ pd->blkg = blkg;
+ pol->ops.blkio_init_group_fn(blkg);
+
+ spin_unlock(&blkg->blkcg->lock);
+ }
+
+ __set_bit(pol->plid, q->blkcg_pols);
+ ret = 0;
+out_unlock:
+ spin_unlock_irq(q->queue_lock);
+out_free:
+ blk_queue_bypass_end(q);
+ list_for_each_entry_safe(pd, n, &pds, alloc_node)
+ kfree(pd);
+ return ret;
}
-EXPORT_SYMBOL_GPL(blkio_policy_register);
+EXPORT_SYMBOL_GPL(blkcg_activate_policy);
-void blkio_policy_unregister(struct blkio_policy_type *blkiop)
+/**
+ * blkcg_deactivate_policy - deactivate a blkcg policy on a request_queue
+ * @q: request_queue of interest
+ * @pol: blkcg policy to deactivate
+ *
+ * Deactivate @pol on @q. Follows the same synchronization rules as
+ * blkcg_activate_policy().
+ */
+void blkcg_deactivate_policy(struct request_queue *q,
+ const struct blkio_policy_type *pol)
{
- spin_lock(&blkio_list_lock);
- list_del_init(&blkiop->list);
- spin_unlock(&blkio_list_lock);
+ struct blkio_group *blkg;
+
+ if (!blkcg_policy_enabled(q, pol))
+ return;
+
+ blk_queue_bypass_start(q);
+ spin_lock_irq(q->queue_lock);
+
+ __clear_bit(pol->plid, q->blkcg_pols);
+
+ /* if no policy is left, no need for blkgs - shoot them down */
+ if (bitmap_empty(q->blkcg_pols, BLKCG_MAX_POLS))
+ blkg_destroy_all(q);
+
+ list_for_each_entry(blkg, &q->blkg_list, q_node) {
+ /* grab blkcg lock too while removing @pd from @blkg */
+ spin_lock(&blkg->blkcg->lock);
+
+ if (pol->ops.blkio_exit_group_fn)
+ pol->ops.blkio_exit_group_fn(blkg);
+
+ kfree(blkg->pd[pol->plid]);
+ blkg->pd[pol->plid] = NULL;
+
+ spin_unlock(&blkg->blkcg->lock);
+ }
+
+ spin_unlock_irq(q->queue_lock);
+ blk_queue_bypass_end(q);
}
-EXPORT_SYMBOL_GPL(blkio_policy_unregister);
+EXPORT_SYMBOL_GPL(blkcg_deactivate_policy);
-static int __init init_cgroup_blkio(void)
+/**
+ * blkio_policy_register - register a blkcg policy
+ * @blkiop: blkcg policy to register
+ *
+ * Register @blkiop with blkcg core. Might sleep and @blkiop may be
+ * modified on successful registration. Returns 0 on success and -errno on
+ * failure.
+ */
+int blkio_policy_register(struct blkio_policy_type *blkiop)
{
- return cgroup_load_subsys(&blkio_subsys);
+ int i, ret;
+
+ mutex_lock(&blkcg_pol_mutex);
+
+ /* find an empty slot */
+ ret = -ENOSPC;
+ for (i = 0; i < BLKCG_MAX_POLS; i++)
+ if (!blkio_policy[i])
+ break;
+ if (i >= BLKCG_MAX_POLS)
+ goto out_unlock;
+
+ /* register and update blkgs */
+ blkiop->plid = i;
+ blkio_policy[i] = blkiop;
+
+ /* everything is in place, add intf files for the new policy */
+ if (blkiop->cftypes)
+ WARN_ON(cgroup_add_cftypes(&blkio_subsys, blkiop->cftypes));
+ ret = 0;
+out_unlock:
+ mutex_unlock(&blkcg_pol_mutex);
+ return ret;
}
+EXPORT_SYMBOL_GPL(blkio_policy_register);
-static void __exit exit_cgroup_blkio(void)
+/**
+ * blkiop_policy_unregister - unregister a blkcg policy
+ * @blkiop: blkcg policy to unregister
+ *
+ * Undo blkio_policy_register(@blkiop). Might sleep.
+ */
+void blkio_policy_unregister(struct blkio_policy_type *blkiop)
{
- cgroup_unload_subsys(&blkio_subsys);
-}
+ mutex_lock(&blkcg_pol_mutex);
+
+ if (WARN_ON(blkio_policy[blkiop->plid] != blkiop))
+ goto out_unlock;
-module_init(init_cgroup_blkio);
-module_exit(exit_cgroup_blkio);
-MODULE_LICENSE("GPL");
+ /* kill the intf files first */
+ if (blkiop->cftypes)
+ cgroup_rm_cftypes(&blkio_subsys, blkiop->cftypes);
+
+ /* unregister and update blkgs */
+ blkio_policy[blkiop->plid] = NULL;
+out_unlock:
+ mutex_unlock(&blkcg_pol_mutex);
+}
+EXPORT_SYMBOL_GPL(blkio_policy_unregister);
projects / mirror_ubuntu-artful-kernel.git / blobdiff