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![Tejun Heo](/assets/img/avatar_default.png)
Now that blkg additions / removals are always done under both q and blkcg locks, the only places RCU locking is necessary are blkg_lookup[_create]() for lookup w/o blkcg lock. This patch drops unncessary RCU locking replacing it with plain blkcg locking as necessary. * blkiocg_pre_destroy() already perform proper locking and don't need RCU. Dropped. * blkio_read_blkg_stats() now uses blkcg->lock instead of RCU read lock. This isn't a hot path. * Now unnecessary synchronize_rcu() from queue exit paths removed. This makes q->nr_blkgs unnecessary. Dropped. * RCU annotation on blkg->q removed. -v2: Vivek pointed out that blkg_lookup_create() still needs to be called under rcu_read_lock(). Updated. -v3: After the update, stats_lock locking in blkio_read_blkg_stats() shouldn't be using _irq variant as it otherwise ends up enabling irq while blkcg->lock is locked. Fixed. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
1794 lines
46 KiB
C
1794 lines
46 KiB
C
/*
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* Common Block IO controller cgroup interface
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*
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* Based on ideas and code from CFQ, CFS and BFQ:
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* Copyright (C) 2003 Jens Axboe <axboe@kernel.dk>
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*
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* Copyright (C) 2008 Fabio Checconi <fabio@gandalf.sssup.it>
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* Paolo Valente <paolo.valente@unimore.it>
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*
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* Copyright (C) 2009 Vivek Goyal <vgoyal@redhat.com>
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* Nauman Rafique <nauman@google.com>
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*/
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#include <linux/ioprio.h>
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#include <linux/seq_file.h>
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#include <linux/kdev_t.h>
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#include <linux/module.h>
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#include <linux/err.h>
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#include <linux/blkdev.h>
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#include <linux/slab.h>
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#include <linux/genhd.h>
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#include <linux/delay.h>
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#include "blk-cgroup.h"
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#include "blk.h"
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#define MAX_KEY_LEN 100
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static DEFINE_SPINLOCK(blkio_list_lock);
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static LIST_HEAD(blkio_list);
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static DEFINE_MUTEX(all_q_mutex);
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static LIST_HEAD(all_q_list);
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struct blkio_cgroup blkio_root_cgroup = { .weight = 2*BLKIO_WEIGHT_DEFAULT };
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EXPORT_SYMBOL_GPL(blkio_root_cgroup);
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static struct blkio_policy_type *blkio_policy[BLKIO_NR_POLICIES];
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static struct cgroup_subsys_state *blkiocg_create(struct cgroup_subsys *,
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struct cgroup *);
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static int blkiocg_can_attach(struct cgroup_subsys *, struct cgroup *,
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struct cgroup_taskset *);
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static void blkiocg_attach(struct cgroup_subsys *, struct cgroup *,
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struct cgroup_taskset *);
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static int blkiocg_pre_destroy(struct cgroup_subsys *, struct cgroup *);
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static void blkiocg_destroy(struct cgroup_subsys *, struct cgroup *);
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static int blkiocg_populate(struct cgroup_subsys *, struct cgroup *);
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/* for encoding cft->private value on file */
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#define BLKIOFILE_PRIVATE(x, val) (((x) << 16) | (val))
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/* What policy owns the file, proportional or throttle */
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#define BLKIOFILE_POLICY(val) (((val) >> 16) & 0xffff)
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#define BLKIOFILE_ATTR(val) ((val) & 0xffff)
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struct cgroup_subsys blkio_subsys = {
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.name = "blkio",
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.create = blkiocg_create,
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.can_attach = blkiocg_can_attach,
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.attach = blkiocg_attach,
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.pre_destroy = blkiocg_pre_destroy,
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.destroy = blkiocg_destroy,
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.populate = blkiocg_populate,
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.subsys_id = blkio_subsys_id,
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.module = THIS_MODULE,
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};
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EXPORT_SYMBOL_GPL(blkio_subsys);
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struct blkio_cgroup *cgroup_to_blkio_cgroup(struct cgroup *cgroup)
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{
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return container_of(cgroup_subsys_state(cgroup, blkio_subsys_id),
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struct blkio_cgroup, css);
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}
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EXPORT_SYMBOL_GPL(cgroup_to_blkio_cgroup);
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struct blkio_cgroup *task_blkio_cgroup(struct task_struct *tsk)
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{
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return container_of(task_subsys_state(tsk, blkio_subsys_id),
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struct blkio_cgroup, css);
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}
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EXPORT_SYMBOL_GPL(task_blkio_cgroup);
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static inline void blkio_update_group_weight(struct blkio_group *blkg,
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int plid, unsigned int weight)
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{
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struct blkio_policy_type *blkiop;
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list_for_each_entry(blkiop, &blkio_list, list) {
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/* If this policy does not own the blkg, do not send updates */
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if (blkiop->plid != plid)
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continue;
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if (blkiop->ops.blkio_update_group_weight_fn)
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blkiop->ops.blkio_update_group_weight_fn(blkg->q,
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blkg, weight);
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}
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}
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static inline void blkio_update_group_bps(struct blkio_group *blkg, int plid,
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u64 bps, int fileid)
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{
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struct blkio_policy_type *blkiop;
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list_for_each_entry(blkiop, &blkio_list, list) {
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/* If this policy does not own the blkg, do not send updates */
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if (blkiop->plid != plid)
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continue;
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if (fileid == BLKIO_THROTL_read_bps_device
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&& blkiop->ops.blkio_update_group_read_bps_fn)
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blkiop->ops.blkio_update_group_read_bps_fn(blkg->q,
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blkg, bps);
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if (fileid == BLKIO_THROTL_write_bps_device
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&& blkiop->ops.blkio_update_group_write_bps_fn)
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blkiop->ops.blkio_update_group_write_bps_fn(blkg->q,
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blkg, bps);
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}
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}
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static inline void blkio_update_group_iops(struct blkio_group *blkg,
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int plid, unsigned int iops,
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int fileid)
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{
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struct blkio_policy_type *blkiop;
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list_for_each_entry(blkiop, &blkio_list, list) {
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/* If this policy does not own the blkg, do not send updates */
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if (blkiop->plid != plid)
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continue;
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if (fileid == BLKIO_THROTL_read_iops_device
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&& blkiop->ops.blkio_update_group_read_iops_fn)
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blkiop->ops.blkio_update_group_read_iops_fn(blkg->q,
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blkg, iops);
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if (fileid == BLKIO_THROTL_write_iops_device
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&& blkiop->ops.blkio_update_group_write_iops_fn)
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blkiop->ops.blkio_update_group_write_iops_fn(blkg->q,
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blkg,iops);
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}
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}
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/*
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* Add to the appropriate stat variable depending on the request type.
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* This should be called with the blkg->stats_lock held.
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*/
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static void blkio_add_stat(uint64_t *stat, uint64_t add, bool direction,
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bool sync)
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{
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if (direction)
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stat[BLKIO_STAT_WRITE] += add;
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else
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stat[BLKIO_STAT_READ] += add;
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if (sync)
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stat[BLKIO_STAT_SYNC] += add;
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else
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stat[BLKIO_STAT_ASYNC] += add;
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}
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/*
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* Decrements the appropriate stat variable if non-zero depending on the
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* request type. Panics on value being zero.
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* This should be called with the blkg->stats_lock held.
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*/
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static void blkio_check_and_dec_stat(uint64_t *stat, bool direction, bool sync)
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{
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if (direction) {
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BUG_ON(stat[BLKIO_STAT_WRITE] == 0);
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stat[BLKIO_STAT_WRITE]--;
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} else {
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BUG_ON(stat[BLKIO_STAT_READ] == 0);
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stat[BLKIO_STAT_READ]--;
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}
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if (sync) {
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BUG_ON(stat[BLKIO_STAT_SYNC] == 0);
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stat[BLKIO_STAT_SYNC]--;
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} else {
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BUG_ON(stat[BLKIO_STAT_ASYNC] == 0);
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stat[BLKIO_STAT_ASYNC]--;
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}
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}
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#ifdef CONFIG_DEBUG_BLK_CGROUP
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/* This should be called with the blkg->stats_lock held. */
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static void blkio_set_start_group_wait_time(struct blkio_group *blkg,
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struct blkio_policy_type *pol,
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struct blkio_group *curr_blkg)
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{
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struct blkg_policy_data *pd = blkg->pd[pol->plid];
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if (blkio_blkg_waiting(&pd->stats))
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return;
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if (blkg == curr_blkg)
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return;
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pd->stats.start_group_wait_time = sched_clock();
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blkio_mark_blkg_waiting(&pd->stats);
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}
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/* This should be called with the blkg->stats_lock held. */
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static void blkio_update_group_wait_time(struct blkio_group_stats *stats)
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{
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unsigned long long now;
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if (!blkio_blkg_waiting(stats))
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return;
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now = sched_clock();
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if (time_after64(now, stats->start_group_wait_time))
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stats->group_wait_time += now - stats->start_group_wait_time;
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blkio_clear_blkg_waiting(stats);
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}
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/* This should be called with the blkg->stats_lock held. */
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static void blkio_end_empty_time(struct blkio_group_stats *stats)
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{
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unsigned long long now;
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if (!blkio_blkg_empty(stats))
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return;
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now = sched_clock();
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if (time_after64(now, stats->start_empty_time))
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stats->empty_time += now - stats->start_empty_time;
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blkio_clear_blkg_empty(stats);
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}
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void blkiocg_update_set_idle_time_stats(struct blkio_group *blkg,
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struct blkio_policy_type *pol)
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{
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struct blkg_policy_data *pd = blkg->pd[pol->plid];
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unsigned long flags;
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spin_lock_irqsave(&blkg->stats_lock, flags);
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BUG_ON(blkio_blkg_idling(&pd->stats));
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pd->stats.start_idle_time = sched_clock();
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blkio_mark_blkg_idling(&pd->stats);
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spin_unlock_irqrestore(&blkg->stats_lock, flags);
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}
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EXPORT_SYMBOL_GPL(blkiocg_update_set_idle_time_stats);
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void blkiocg_update_idle_time_stats(struct blkio_group *blkg,
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struct blkio_policy_type *pol)
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{
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struct blkg_policy_data *pd = blkg->pd[pol->plid];
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unsigned long flags;
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unsigned long long now;
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struct blkio_group_stats *stats;
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spin_lock_irqsave(&blkg->stats_lock, flags);
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stats = &pd->stats;
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if (blkio_blkg_idling(stats)) {
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now = sched_clock();
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if (time_after64(now, stats->start_idle_time))
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stats->idle_time += now - stats->start_idle_time;
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blkio_clear_blkg_idling(stats);
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}
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spin_unlock_irqrestore(&blkg->stats_lock, flags);
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}
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EXPORT_SYMBOL_GPL(blkiocg_update_idle_time_stats);
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void blkiocg_update_avg_queue_size_stats(struct blkio_group *blkg,
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struct blkio_policy_type *pol)
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{
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struct blkg_policy_data *pd = blkg->pd[pol->plid];
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unsigned long flags;
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struct blkio_group_stats *stats;
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spin_lock_irqsave(&blkg->stats_lock, flags);
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stats = &pd->stats;
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stats->avg_queue_size_sum +=
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stats->stat_arr[BLKIO_STAT_QUEUED][BLKIO_STAT_READ] +
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stats->stat_arr[BLKIO_STAT_QUEUED][BLKIO_STAT_WRITE];
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stats->avg_queue_size_samples++;
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blkio_update_group_wait_time(stats);
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spin_unlock_irqrestore(&blkg->stats_lock, flags);
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}
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EXPORT_SYMBOL_GPL(blkiocg_update_avg_queue_size_stats);
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void blkiocg_set_start_empty_time(struct blkio_group *blkg,
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struct blkio_policy_type *pol)
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{
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struct blkg_policy_data *pd = blkg->pd[pol->plid];
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unsigned long flags;
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struct blkio_group_stats *stats;
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spin_lock_irqsave(&blkg->stats_lock, flags);
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stats = &pd->stats;
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if (stats->stat_arr[BLKIO_STAT_QUEUED][BLKIO_STAT_READ] ||
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stats->stat_arr[BLKIO_STAT_QUEUED][BLKIO_STAT_WRITE]) {
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spin_unlock_irqrestore(&blkg->stats_lock, flags);
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return;
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}
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/*
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* group is already marked empty. This can happen if cfqq got new
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* request in parent group and moved to this group while being added
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* to service tree. Just ignore the event and move on.
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*/
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if(blkio_blkg_empty(stats)) {
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spin_unlock_irqrestore(&blkg->stats_lock, flags);
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return;
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}
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stats->start_empty_time = sched_clock();
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blkio_mark_blkg_empty(stats);
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spin_unlock_irqrestore(&blkg->stats_lock, flags);
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}
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EXPORT_SYMBOL_GPL(blkiocg_set_start_empty_time);
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void blkiocg_update_dequeue_stats(struct blkio_group *blkg,
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struct blkio_policy_type *pol,
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unsigned long dequeue)
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{
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struct blkg_policy_data *pd = blkg->pd[pol->plid];
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pd->stats.dequeue += dequeue;
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}
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EXPORT_SYMBOL_GPL(blkiocg_update_dequeue_stats);
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#else
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static inline void blkio_set_start_group_wait_time(struct blkio_group *blkg,
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struct blkio_policy_type *pol,
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struct blkio_group *curr_blkg) { }
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static inline void blkio_end_empty_time(struct blkio_group_stats *stats) { }
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#endif
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void blkiocg_update_io_add_stats(struct blkio_group *blkg,
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struct blkio_policy_type *pol,
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struct blkio_group *curr_blkg, bool direction,
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bool sync)
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{
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struct blkg_policy_data *pd = blkg->pd[pol->plid];
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unsigned long flags;
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spin_lock_irqsave(&blkg->stats_lock, flags);
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blkio_add_stat(pd->stats.stat_arr[BLKIO_STAT_QUEUED], 1, direction,
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sync);
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blkio_end_empty_time(&pd->stats);
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blkio_set_start_group_wait_time(blkg, pol, curr_blkg);
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spin_unlock_irqrestore(&blkg->stats_lock, flags);
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}
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EXPORT_SYMBOL_GPL(blkiocg_update_io_add_stats);
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void blkiocg_update_io_remove_stats(struct blkio_group *blkg,
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struct blkio_policy_type *pol,
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bool direction, bool sync)
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{
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struct blkg_policy_data *pd = blkg->pd[pol->plid];
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unsigned long flags;
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spin_lock_irqsave(&blkg->stats_lock, flags);
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blkio_check_and_dec_stat(pd->stats.stat_arr[BLKIO_STAT_QUEUED],
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direction, sync);
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spin_unlock_irqrestore(&blkg->stats_lock, flags);
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}
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EXPORT_SYMBOL_GPL(blkiocg_update_io_remove_stats);
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void blkiocg_update_timeslice_used(struct blkio_group *blkg,
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struct blkio_policy_type *pol,
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unsigned long time,
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unsigned long unaccounted_time)
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{
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struct blkg_policy_data *pd = blkg->pd[pol->plid];
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unsigned long flags;
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spin_lock_irqsave(&blkg->stats_lock, flags);
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pd->stats.time += time;
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#ifdef CONFIG_DEBUG_BLK_CGROUP
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pd->stats.unaccounted_time += unaccounted_time;
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#endif
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spin_unlock_irqrestore(&blkg->stats_lock, flags);
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}
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EXPORT_SYMBOL_GPL(blkiocg_update_timeslice_used);
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/*
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* should be called under rcu read lock or queue lock to make sure blkg pointer
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* is valid.
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*/
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void blkiocg_update_dispatch_stats(struct blkio_group *blkg,
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struct blkio_policy_type *pol,
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uint64_t bytes, bool direction, bool sync)
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{
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struct blkg_policy_data *pd = blkg->pd[pol->plid];
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struct blkio_group_stats_cpu *stats_cpu;
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unsigned long flags;
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/*
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* Disabling interrupts to provide mutual exclusion between two
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* writes on same cpu. It probably is not needed for 64bit. Not
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* optimizing that case yet.
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*/
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local_irq_save(flags);
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stats_cpu = this_cpu_ptr(pd->stats_cpu);
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u64_stats_update_begin(&stats_cpu->syncp);
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stats_cpu->sectors += bytes >> 9;
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blkio_add_stat(stats_cpu->stat_arr_cpu[BLKIO_STAT_CPU_SERVICED],
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1, direction, sync);
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blkio_add_stat(stats_cpu->stat_arr_cpu[BLKIO_STAT_CPU_SERVICE_BYTES],
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bytes, direction, sync);
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u64_stats_update_end(&stats_cpu->syncp);
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local_irq_restore(flags);
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}
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EXPORT_SYMBOL_GPL(blkiocg_update_dispatch_stats);
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void blkiocg_update_completion_stats(struct blkio_group *blkg,
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struct blkio_policy_type *pol,
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uint64_t start_time,
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uint64_t io_start_time, bool direction,
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bool sync)
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{
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struct blkg_policy_data *pd = blkg->pd[pol->plid];
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struct blkio_group_stats *stats;
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unsigned long flags;
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unsigned long long now = sched_clock();
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spin_lock_irqsave(&blkg->stats_lock, flags);
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stats = &pd->stats;
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if (time_after64(now, io_start_time))
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blkio_add_stat(stats->stat_arr[BLKIO_STAT_SERVICE_TIME],
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now - io_start_time, direction, sync);
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if (time_after64(io_start_time, start_time))
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blkio_add_stat(stats->stat_arr[BLKIO_STAT_WAIT_TIME],
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io_start_time - start_time, direction, sync);
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spin_unlock_irqrestore(&blkg->stats_lock, flags);
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}
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EXPORT_SYMBOL_GPL(blkiocg_update_completion_stats);
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/* Merged stats are per cpu. */
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void blkiocg_update_io_merged_stats(struct blkio_group *blkg,
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struct blkio_policy_type *pol,
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bool direction, bool sync)
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{
|
|
struct blkg_policy_data *pd = blkg->pd[pol->plid];
|
|
struct blkio_group_stats_cpu *stats_cpu;
|
|
unsigned long flags;
|
|
|
|
/*
|
|
* 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(pd->stats_cpu);
|
|
|
|
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);
|
|
}
|
|
EXPORT_SYMBOL_GPL(blkiocg_update_io_merged_stats);
|
|
|
|
/**
|
|
* blkg_free - free a blkg
|
|
* @blkg: blkg to free
|
|
*
|
|
* Free @blkg which may be partially allocated.
|
|
*/
|
|
static void blkg_free(struct blkio_group *blkg)
|
|
{
|
|
int i;
|
|
|
|
if (!blkg)
|
|
return;
|
|
|
|
for (i = 0; i < BLKIO_NR_POLICIES; i++) {
|
|
struct blkg_policy_data *pd = blkg->pd[i];
|
|
|
|
if (pd) {
|
|
free_percpu(pd->stats_cpu);
|
|
kfree(pd);
|
|
}
|
|
}
|
|
|
|
kfree(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.
|
|
*
|
|
* FIXME: Should be called with queue locked but currently isn't due to
|
|
* percpu stat breakage.
|
|
*/
|
|
static struct blkio_group *blkg_alloc(struct blkio_cgroup *blkcg,
|
|
struct request_queue *q)
|
|
{
|
|
struct blkio_group *blkg;
|
|
int i;
|
|
|
|
/* alloc and init base part */
|
|
blkg = kzalloc_node(sizeof(*blkg), GFP_ATOMIC, q->node);
|
|
if (!blkg)
|
|
return NULL;
|
|
|
|
spin_lock_init(&blkg->stats_lock);
|
|
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));
|
|
|
|
for (i = 0; i < BLKIO_NR_POLICIES; i++) {
|
|
struct blkio_policy_type *pol = blkio_policy[i];
|
|
struct blkg_policy_data *pd;
|
|
|
|
if (!pol)
|
|
continue;
|
|
|
|
/* alloc per-policy data and attach it to blkg */
|
|
pd = kzalloc_node(sizeof(*pd) + pol->pdata_size, GFP_ATOMIC,
|
|
q->node);
|
|
if (!pd) {
|
|
blkg_free(blkg);
|
|
return NULL;
|
|
}
|
|
|
|
blkg->pd[i] = pd;
|
|
pd->blkg = blkg;
|
|
|
|
/* broken, read comment in the callsite */
|
|
pd->stats_cpu = alloc_percpu(struct blkio_group_stats_cpu);
|
|
if (!pd->stats_cpu) {
|
|
blkg_free(blkg);
|
|
return NULL;
|
|
}
|
|
}
|
|
|
|
/* invoke per-policy init */
|
|
for (i = 0; i < BLKIO_NR_POLICIES; i++) {
|
|
struct blkio_policy_type *pol = blkio_policy[i];
|
|
|
|
if (pol)
|
|
pol->ops.blkio_init_group_fn(blkg);
|
|
}
|
|
|
|
return blkg;
|
|
}
|
|
|
|
struct blkio_group *blkg_lookup_create(struct blkio_cgroup *blkcg,
|
|
struct request_queue *q,
|
|
enum blkio_policy_id plid,
|
|
bool for_root)
|
|
__releases(q->queue_lock) __acquires(q->queue_lock)
|
|
{
|
|
struct blkio_group *blkg, *new_blkg;
|
|
|
|
WARN_ON_ONCE(!rcu_read_lock_held());
|
|
lockdep_assert_held(q->queue_lock);
|
|
|
|
/*
|
|
* This could be the first entry point of blkcg implementation and
|
|
* we shouldn't allow anything to go through for a bypassing queue.
|
|
* The following can be removed if blkg lookup is guaranteed to
|
|
* fail on a bypassing queue.
|
|
*/
|
|
if (unlikely(blk_queue_bypass(q)) && !for_root)
|
|
return ERR_PTR(blk_queue_dead(q) ? -EINVAL : -EBUSY);
|
|
|
|
blkg = blkg_lookup(blkcg, q);
|
|
if (blkg)
|
|
return blkg;
|
|
|
|
/* blkg holds a reference to blkcg */
|
|
if (!css_tryget(&blkcg->css))
|
|
return ERR_PTR(-EINVAL);
|
|
|
|
/*
|
|
* Allocate and initialize.
|
|
*
|
|
* FIXME: The following is broken. Percpu memory allocation
|
|
* requires %GFP_KERNEL context and can't be performed from IO
|
|
* path. Allocation here should inherently be atomic and the
|
|
* following lock dancing can be removed once the broken percpu
|
|
* allocation is fixed.
|
|
*/
|
|
spin_unlock_irq(q->queue_lock);
|
|
rcu_read_unlock();
|
|
|
|
new_blkg = blkg_alloc(blkcg, q);
|
|
|
|
rcu_read_lock();
|
|
spin_lock_irq(q->queue_lock);
|
|
|
|
/* did bypass get turned on inbetween? */
|
|
if (unlikely(blk_queue_bypass(q)) && !for_root) {
|
|
blkg = ERR_PTR(blk_queue_dead(q) ? -EINVAL : -EBUSY);
|
|
goto out;
|
|
}
|
|
|
|
/* did someone beat us to it? */
|
|
blkg = blkg_lookup(blkcg, q);
|
|
if (unlikely(blkg))
|
|
goto out;
|
|
|
|
/* did alloc fail? */
|
|
if (unlikely(!new_blkg)) {
|
|
blkg = ERR_PTR(-ENOMEM);
|
|
goto out;
|
|
}
|
|
|
|
/* insert */
|
|
spin_lock(&blkcg->lock);
|
|
swap(blkg, new_blkg);
|
|
|
|
hlist_add_head_rcu(&blkg->blkcg_node, &blkcg->blkg_list);
|
|
list_add(&blkg->q_node, &q->blkg_list);
|
|
|
|
spin_unlock(&blkcg->lock);
|
|
out:
|
|
blkg_free(new_blkg);
|
|
return blkg;
|
|
}
|
|
EXPORT_SYMBOL_GPL(blkg_lookup_create);
|
|
|
|
/* called under rcu_read_lock(). */
|
|
struct blkio_group *blkg_lookup(struct blkio_cgroup *blkcg,
|
|
struct request_queue *q)
|
|
{
|
|
struct blkio_group *blkg;
|
|
struct hlist_node *n;
|
|
|
|
hlist_for_each_entry_rcu(blkg, n, &blkcg->blkg_list, blkcg_node)
|
|
if (blkg->q == q)
|
|
return blkg;
|
|
return NULL;
|
|
}
|
|
EXPORT_SYMBOL_GPL(blkg_lookup);
|
|
|
|
static void blkg_destroy(struct blkio_group *blkg)
|
|
{
|
|
struct request_queue *q = blkg->q;
|
|
struct blkio_cgroup *blkcg = blkg->blkcg;
|
|
|
|
lockdep_assert_held(q->queue_lock);
|
|
lockdep_assert_held(&blkcg->lock);
|
|
|
|
/* 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);
|
|
|
|
/*
|
|
* Put the reference taken at the time of creation so that when all
|
|
* queues are gone, group can be destroyed.
|
|
*/
|
|
blkg_put(blkg);
|
|
}
|
|
|
|
/*
|
|
* XXX: This updates blkg policy data in-place for root blkg, which is
|
|
* necessary across elevator switch and policy registration as root blkgs
|
|
* aren't shot down. This broken and racy implementation is temporary.
|
|
* Eventually, blkg shoot down will be replaced by proper in-place update.
|
|
*/
|
|
void update_root_blkg_pd(struct request_queue *q, enum blkio_policy_id plid)
|
|
{
|
|
struct blkio_policy_type *pol = blkio_policy[plid];
|
|
struct blkio_group *blkg = blkg_lookup(&blkio_root_cgroup, q);
|
|
struct blkg_policy_data *pd;
|
|
|
|
if (!blkg)
|
|
return;
|
|
|
|
kfree(blkg->pd[plid]);
|
|
blkg->pd[plid] = NULL;
|
|
|
|
if (!pol)
|
|
return;
|
|
|
|
pd = kzalloc(sizeof(*pd) + pol->pdata_size, GFP_KERNEL);
|
|
WARN_ON_ONCE(!pd);
|
|
|
|
pd->stats_cpu = alloc_percpu(struct blkio_group_stats_cpu);
|
|
WARN_ON_ONCE(!pd->stats_cpu);
|
|
|
|
blkg->pd[plid] = pd;
|
|
pd->blkg = blkg;
|
|
pol->ops.blkio_init_group_fn(blkg);
|
|
}
|
|
EXPORT_SYMBOL_GPL(update_root_blkg_pd);
|
|
|
|
/**
|
|
* blkg_destroy_all - destroy all blkgs associated with a request_queue
|
|
* @q: request_queue of interest
|
|
* @destroy_root: whether to destroy root blkg or not
|
|
*
|
|
* Destroy blkgs associated with @q. If @destroy_root is %true, all are
|
|
* destroyed; otherwise, root blkg is left alone.
|
|
*/
|
|
void blkg_destroy_all(struct request_queue *q, bool destroy_root)
|
|
{
|
|
struct blkio_group *blkg, *n;
|
|
|
|
spin_lock_irq(q->queue_lock);
|
|
|
|
list_for_each_entry_safe(blkg, n, &q->blkg_list, q_node) {
|
|
struct blkio_cgroup *blkcg = blkg->blkcg;
|
|
|
|
/* skip root? */
|
|
if (!destroy_root && blkg->blkcg == &blkio_root_cgroup)
|
|
continue;
|
|
|
|
spin_lock(&blkcg->lock);
|
|
blkg_destroy(blkg);
|
|
spin_unlock(&blkcg->lock);
|
|
}
|
|
|
|
spin_unlock_irq(q->queue_lock);
|
|
}
|
|
EXPORT_SYMBOL_GPL(blkg_destroy_all);
|
|
|
|
static void blkg_rcu_free(struct rcu_head *rcu_head)
|
|
{
|
|
blkg_free(container_of(rcu_head, struct blkio_group, rcu_head));
|
|
}
|
|
|
|
void __blkg_release(struct blkio_group *blkg)
|
|
{
|
|
/* release the extra blkcg reference this blkg has been holding */
|
|
css_put(&blkg->blkcg->css);
|
|
|
|
/*
|
|
* 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.
|
|
*
|
|
* Having a reference to blkg under an rcu allows acess to only
|
|
* values local to groups like group stats and group rate limits
|
|
*/
|
|
call_rcu(&blkg->rcu_head, blkg_rcu_free);
|
|
}
|
|
EXPORT_SYMBOL_GPL(__blkg_release);
|
|
|
|
static void blkio_reset_stats_cpu(struct blkio_group *blkg, int plid)
|
|
{
|
|
struct blkg_policy_data *pd = blkg->pd[plid];
|
|
struct blkio_group_stats_cpu *stats_cpu;
|
|
int i, j, k;
|
|
/*
|
|
* 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.
|
|
*
|
|
* 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.
|
|
*/
|
|
for_each_possible_cpu(i) {
|
|
stats_cpu = per_cpu_ptr(pd->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;
|
|
}
|
|
}
|
|
|
|
static int
|
|
blkiocg_reset_stats(struct cgroup *cgroup, struct cftype *cftype, u64 val)
|
|
{
|
|
struct blkio_cgroup *blkcg;
|
|
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);
|
|
spin_lock(&blkio_list_lock);
|
|
spin_lock_irq(&blkcg->lock);
|
|
hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node) {
|
|
struct blkio_policy_type *pol;
|
|
|
|
list_for_each_entry(pol, &blkio_list, list) {
|
|
struct blkg_policy_data *pd = blkg->pd[pol->plid];
|
|
|
|
spin_lock(&blkg->stats_lock);
|
|
stats = &pd->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, pol->plid);
|
|
}
|
|
}
|
|
|
|
spin_unlock_irq(&blkcg->lock);
|
|
spin_unlock(&blkio_list_lock);
|
|
return 0;
|
|
}
|
|
|
|
static void blkio_get_key_name(enum stat_sub_type type, const char *dname,
|
|
char *str, int chars_left, bool diskname_only)
|
|
{
|
|
snprintf(str, chars_left, "%s", dname);
|
|
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, const char *dname)
|
|
{
|
|
blkio_get_key_name(0, dname, str, chars_left, true);
|
|
cb->fill(cb, str, val);
|
|
return val;
|
|
}
|
|
|
|
|
|
static uint64_t blkio_read_stat_cpu(struct blkio_group *blkg, int plid,
|
|
enum stat_type_cpu type, enum stat_sub_type sub_type)
|
|
{
|
|
struct blkg_policy_data *pd = blkg->pd[plid];
|
|
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(pd->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, int plid,
|
|
struct cgroup_map_cb *cb, const char *dname,
|
|
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, plid, type, 0);
|
|
return blkio_fill_stat(key_str, MAX_KEY_LEN - 1, val, cb,
|
|
dname);
|
|
}
|
|
|
|
for (sub_type = BLKIO_STAT_READ; sub_type < BLKIO_STAT_TOTAL;
|
|
sub_type++) {
|
|
blkio_get_key_name(sub_type, dname, key_str, MAX_KEY_LEN,
|
|
false);
|
|
val = blkio_read_stat_cpu(blkg, plid, type, sub_type);
|
|
cb->fill(cb, key_str, val);
|
|
}
|
|
|
|
disk_total = blkio_read_stat_cpu(blkg, plid, type, BLKIO_STAT_READ) +
|
|
blkio_read_stat_cpu(blkg, plid, type, BLKIO_STAT_WRITE);
|
|
|
|
blkio_get_key_name(BLKIO_STAT_TOTAL, dname, 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, int plid,
|
|
struct cgroup_map_cb *cb, const char *dname,
|
|
enum stat_type type)
|
|
{
|
|
struct blkg_policy_data *pd = blkg->pd[plid];
|
|
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,
|
|
pd->stats.time, cb, dname);
|
|
#ifdef CONFIG_DEBUG_BLK_CGROUP
|
|
if (type == BLKIO_STAT_UNACCOUNTED_TIME)
|
|
return blkio_fill_stat(key_str, MAX_KEY_LEN - 1,
|
|
pd->stats.unaccounted_time, cb, dname);
|
|
if (type == BLKIO_STAT_AVG_QUEUE_SIZE) {
|
|
uint64_t sum = pd->stats.avg_queue_size_sum;
|
|
uint64_t samples = pd->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, dname);
|
|
}
|
|
if (type == BLKIO_STAT_GROUP_WAIT_TIME)
|
|
return blkio_fill_stat(key_str, MAX_KEY_LEN - 1,
|
|
pd->stats.group_wait_time, cb, dname);
|
|
if (type == BLKIO_STAT_IDLE_TIME)
|
|
return blkio_fill_stat(key_str, MAX_KEY_LEN - 1,
|
|
pd->stats.idle_time, cb, dname);
|
|
if (type == BLKIO_STAT_EMPTY_TIME)
|
|
return blkio_fill_stat(key_str, MAX_KEY_LEN - 1,
|
|
pd->stats.empty_time, cb, dname);
|
|
if (type == BLKIO_STAT_DEQUEUE)
|
|
return blkio_fill_stat(key_str, MAX_KEY_LEN - 1,
|
|
pd->stats.dequeue, cb, dname);
|
|
#endif
|
|
|
|
for (sub_type = BLKIO_STAT_READ; sub_type < BLKIO_STAT_TOTAL;
|
|
sub_type++) {
|
|
blkio_get_key_name(sub_type, dname, key_str, MAX_KEY_LEN,
|
|
false);
|
|
cb->fill(cb, key_str, pd->stats.stat_arr[type][sub_type]);
|
|
}
|
|
disk_total = pd->stats.stat_arr[type][BLKIO_STAT_READ] +
|
|
pd->stats.stat_arr[type][BLKIO_STAT_WRITE];
|
|
blkio_get_key_name(BLKIO_STAT_TOTAL, dname, 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, enum blkio_policy_id plid,
|
|
int fileid, struct blkio_cgroup *blkcg)
|
|
{
|
|
struct gendisk *disk = NULL;
|
|
struct blkio_group *blkg = NULL;
|
|
struct blkg_policy_data *pd;
|
|
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;
|
|
|
|
disk = get_gendisk(dev, &part);
|
|
if (!disk || part)
|
|
goto out;
|
|
|
|
rcu_read_lock();
|
|
|
|
spin_lock_irq(disk->queue->queue_lock);
|
|
blkg = blkg_lookup_create(blkcg, disk->queue, plid, false);
|
|
spin_unlock_irq(disk->queue->queue_lock);
|
|
|
|
if (IS_ERR(blkg)) {
|
|
ret = PTR_ERR(blkg);
|
|
goto out_unlock;
|
|
}
|
|
|
|
pd = blkg->pd[plid];
|
|
|
|
switch (plid) {
|
|
case BLKIO_POLICY_PROP:
|
|
if ((temp < BLKIO_WEIGHT_MIN && temp > 0) ||
|
|
temp > BLKIO_WEIGHT_MAX)
|
|
goto out_unlock;
|
|
|
|
pd->conf.weight = temp;
|
|
blkio_update_group_weight(blkg, plid, temp ?: blkcg->weight);
|
|
break;
|
|
case BLKIO_POLICY_THROTL:
|
|
switch(fileid) {
|
|
case BLKIO_THROTL_read_bps_device:
|
|
pd->conf.bps[READ] = temp;
|
|
blkio_update_group_bps(blkg, plid, temp ?: -1, fileid);
|
|
break;
|
|
case BLKIO_THROTL_write_bps_device:
|
|
pd->conf.bps[WRITE] = temp;
|
|
blkio_update_group_bps(blkg, plid, temp ?: -1, fileid);
|
|
break;
|
|
case BLKIO_THROTL_read_iops_device:
|
|
if (temp > THROTL_IOPS_MAX)
|
|
goto out_unlock;
|
|
pd->conf.iops[READ] = temp;
|
|
blkio_update_group_iops(blkg, plid, temp ?: -1, fileid);
|
|
break;
|
|
case BLKIO_THROTL_write_iops_device:
|
|
if (temp > THROTL_IOPS_MAX)
|
|
goto out_unlock;
|
|
pd->conf.iops[WRITE] = temp;
|
|
blkio_update_group_iops(blkg, plid, temp ?: -1, fileid);
|
|
break;
|
|
}
|
|
break;
|
|
default:
|
|
BUG();
|
|
}
|
|
ret = 0;
|
|
out_unlock:
|
|
rcu_read_unlock();
|
|
out:
|
|
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);
|
|
return restart_syscall();
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
static int blkiocg_file_write(struct cgroup *cgrp, struct cftype *cft,
|
|
const char *buffer)
|
|
{
|
|
int ret = 0;
|
|
char *buf;
|
|
struct blkio_cgroup *blkcg = cgroup_to_blkio_cgroup(cgrp);
|
|
enum blkio_policy_id plid = BLKIOFILE_POLICY(cft->private);
|
|
int fileid = BLKIOFILE_ATTR(cft->private);
|
|
|
|
buf = kstrdup(buffer, GFP_KERNEL);
|
|
if (!buf)
|
|
return -ENOMEM;
|
|
|
|
ret = blkio_policy_parse_and_set(buf, plid, fileid, blkcg);
|
|
kfree(buf);
|
|
return ret;
|
|
}
|
|
|
|
static const char *blkg_dev_name(struct blkio_group *blkg)
|
|
{
|
|
/* 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;
|
|
}
|
|
|
|
static void blkio_print_group_conf(struct cftype *cft, struct blkio_group *blkg,
|
|
struct seq_file *m)
|
|
{
|
|
int plid = BLKIOFILE_POLICY(cft->private);
|
|
int fileid = BLKIOFILE_ATTR(cft->private);
|
|
struct blkg_policy_data *pd = blkg->pd[plid];
|
|
const char *dname = blkg_dev_name(blkg);
|
|
int rw = WRITE;
|
|
|
|
if (!dname)
|
|
return;
|
|
|
|
switch (plid) {
|
|
case BLKIO_POLICY_PROP:
|
|
if (pd->conf.weight)
|
|
seq_printf(m, "%s\t%u\n",
|
|
dname, pd->conf.weight);
|
|
break;
|
|
case BLKIO_POLICY_THROTL:
|
|
switch (fileid) {
|
|
case BLKIO_THROTL_read_bps_device:
|
|
rw = READ;
|
|
case BLKIO_THROTL_write_bps_device:
|
|
if (pd->conf.bps[rw])
|
|
seq_printf(m, "%s\t%llu\n",
|
|
dname, pd->conf.bps[rw]);
|
|
break;
|
|
case BLKIO_THROTL_read_iops_device:
|
|
rw = READ;
|
|
case BLKIO_THROTL_write_iops_device:
|
|
if (pd->conf.iops[rw])
|
|
seq_printf(m, "%s\t%u\n",
|
|
dname, pd->conf.iops[rw]);
|
|
break;
|
|
}
|
|
break;
|
|
default:
|
|
BUG();
|
|
}
|
|
}
|
|
|
|
/* cgroup files which read their data from policy nodes end up here */
|
|
static void blkio_read_conf(struct cftype *cft, struct blkio_cgroup *blkcg,
|
|
struct seq_file *m)
|
|
{
|
|
struct blkio_group *blkg;
|
|
struct hlist_node *n;
|
|
|
|
spin_lock_irq(&blkcg->lock);
|
|
hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node)
|
|
blkio_print_group_conf(cft, blkg, m);
|
|
spin_unlock_irq(&blkcg->lock);
|
|
}
|
|
|
|
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_conf(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_conf(cft, blkcg, m);
|
|
return 0;
|
|
default:
|
|
BUG();
|
|
}
|
|
break;
|
|
default:
|
|
BUG();
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
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)
|
|
{
|
|
struct blkio_group *blkg;
|
|
struct hlist_node *n;
|
|
uint64_t cgroup_total = 0;
|
|
|
|
spin_lock_irq(&blkcg->lock);
|
|
|
|
hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node) {
|
|
const char *dname = blkg_dev_name(blkg);
|
|
int plid = BLKIOFILE_POLICY(cft->private);
|
|
|
|
if (!dname)
|
|
continue;
|
|
if (pcpu) {
|
|
cgroup_total += blkio_get_stat_cpu(blkg, plid,
|
|
cb, dname, type);
|
|
} else {
|
|
spin_lock(&blkg->stats_lock);
|
|
cgroup_total += blkio_get_stat(blkg, plid,
|
|
cb, dname, type);
|
|
spin_unlock(&blkg->stats_lock);
|
|
}
|
|
}
|
|
if (show_total)
|
|
cb->fill(cb, "Total", cgroup_total);
|
|
|
|
spin_unlock_irq(&blkcg->lock);
|
|
return 0;
|
|
}
|
|
|
|
/* 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)
|
|
{
|
|
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();
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int blkio_weight_write(struct blkio_cgroup *blkcg, int plid, u64 val)
|
|
{
|
|
struct blkio_group *blkg;
|
|
struct hlist_node *n;
|
|
|
|
if (val < BLKIO_WEIGHT_MIN || val > BLKIO_WEIGHT_MAX)
|
|
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) {
|
|
struct blkg_policy_data *pd = blkg->pd[plid];
|
|
|
|
if (!pd->conf.weight)
|
|
blkio_update_group_weight(blkg, plid, blkcg->weight);
|
|
}
|
|
|
|
spin_unlock_irq(&blkcg->lock);
|
|
spin_unlock(&blkio_list_lock);
|
|
return 0;
|
|
}
|
|
|
|
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);
|
|
|
|
blkcg = cgroup_to_blkio_cgroup(cgrp);
|
|
|
|
switch(plid) {
|
|
case BLKIO_POLICY_PROP:
|
|
switch(name) {
|
|
case BLKIO_PROP_weight:
|
|
return (u64)blkcg->weight;
|
|
}
|
|
break;
|
|
default:
|
|
BUG();
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static int
|
|
blkiocg_file_write_u64(struct cgroup *cgrp, struct cftype *cft, u64 val)
|
|
{
|
|
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, plid, val);
|
|
}
|
|
break;
|
|
default:
|
|
BUG();
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
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
|
|
};
|
|
|
|
static int blkiocg_populate(struct cgroup_subsys *subsys, struct cgroup *cgroup)
|
|
{
|
|
return cgroup_add_files(cgroup, subsys, blkio_files,
|
|
ARRAY_SIZE(blkio_files));
|
|
}
|
|
|
|
/**
|
|
* blkiocg_pre_destroy - cgroup pre_destroy callback
|
|
* @subsys: cgroup subsys
|
|
* @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_subsys *subsys,
|
|
struct cgroup *cgroup)
|
|
{
|
|
struct blkio_cgroup *blkcg = cgroup_to_blkio_cgroup(cgroup);
|
|
|
|
spin_lock_irq(&blkcg->lock);
|
|
|
|
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(&blkcg->lock);
|
|
}
|
|
}
|
|
|
|
spin_unlock_irq(&blkcg->lock);
|
|
return 0;
|
|
}
|
|
|
|
static void blkiocg_destroy(struct cgroup_subsys *subsys, struct cgroup *cgroup)
|
|
{
|
|
struct blkio_cgroup *blkcg = cgroup_to_blkio_cgroup(cgroup);
|
|
|
|
if (blkcg != &blkio_root_cgroup)
|
|
kfree(blkcg);
|
|
}
|
|
|
|
static struct cgroup_subsys_state *
|
|
blkiocg_create(struct cgroup_subsys *subsys, struct cgroup *cgroup)
|
|
{
|
|
struct blkio_cgroup *blkcg;
|
|
struct cgroup *parent = cgroup->parent;
|
|
|
|
if (!parent) {
|
|
blkcg = &blkio_root_cgroup;
|
|
goto done;
|
|
}
|
|
|
|
blkcg = kzalloc(sizeof(*blkcg), GFP_KERNEL);
|
|
if (!blkcg)
|
|
return ERR_PTR(-ENOMEM);
|
|
|
|
blkcg->weight = BLKIO_WEIGHT_DEFAULT;
|
|
done:
|
|
spin_lock_init(&blkcg->lock);
|
|
INIT_HLIST_HEAD(&blkcg->blkg_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)
|
|
{
|
|
int ret;
|
|
|
|
might_sleep();
|
|
|
|
ret = blk_throtl_init(q);
|
|
if (ret)
|
|
return ret;
|
|
|
|
mutex_lock(&all_q_mutex);
|
|
INIT_LIST_HEAD(&q->all_q_node);
|
|
list_add_tail(&q->all_q_node, &all_q_list);
|
|
mutex_unlock(&all_q_mutex);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* 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)
|
|
{
|
|
mutex_lock(&all_q_mutex);
|
|
list_del_init(&q->all_q_node);
|
|
mutex_unlock(&all_q_mutex);
|
|
|
|
blkg_destroy_all(q, true);
|
|
|
|
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
|
|
* of the main cic data structures. For now we allow a task to change
|
|
* its cgroup only if it's the only owner of its ioc.
|
|
*/
|
|
static int blkiocg_can_attach(struct cgroup_subsys *ss, struct cgroup *cgrp,
|
|
struct cgroup_taskset *tset)
|
|
{
|
|
struct task_struct *task;
|
|
struct io_context *ioc;
|
|
int ret = 0;
|
|
|
|
/* task_lock() is needed to avoid races with exit_io_context() */
|
|
cgroup_taskset_for_each(task, cgrp, tset) {
|
|
task_lock(task);
|
|
ioc = task->io_context;
|
|
if (ioc && atomic_read(&ioc->nr_tasks) > 1)
|
|
ret = -EINVAL;
|
|
task_unlock(task);
|
|
if (ret)
|
|
break;
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
static void blkiocg_attach(struct cgroup_subsys *ss, 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);
|
|
}
|
|
}
|
|
}
|
|
|
|
static void blkcg_bypass_start(void)
|
|
__acquires(&all_q_mutex)
|
|
{
|
|
struct request_queue *q;
|
|
|
|
mutex_lock(&all_q_mutex);
|
|
|
|
list_for_each_entry(q, &all_q_list, all_q_node) {
|
|
blk_queue_bypass_start(q);
|
|
blkg_destroy_all(q, false);
|
|
}
|
|
}
|
|
|
|
static void blkcg_bypass_end(void)
|
|
__releases(&all_q_mutex)
|
|
{
|
|
struct request_queue *q;
|
|
|
|
list_for_each_entry(q, &all_q_list, all_q_node)
|
|
blk_queue_bypass_end(q);
|
|
|
|
mutex_unlock(&all_q_mutex);
|
|
}
|
|
|
|
void blkio_policy_register(struct blkio_policy_type *blkiop)
|
|
{
|
|
struct request_queue *q;
|
|
|
|
blkcg_bypass_start();
|
|
spin_lock(&blkio_list_lock);
|
|
|
|
BUG_ON(blkio_policy[blkiop->plid]);
|
|
blkio_policy[blkiop->plid] = blkiop;
|
|
list_add_tail(&blkiop->list, &blkio_list);
|
|
|
|
spin_unlock(&blkio_list_lock);
|
|
list_for_each_entry(q, &all_q_list, all_q_node)
|
|
update_root_blkg_pd(q, blkiop->plid);
|
|
blkcg_bypass_end();
|
|
}
|
|
EXPORT_SYMBOL_GPL(blkio_policy_register);
|
|
|
|
void blkio_policy_unregister(struct blkio_policy_type *blkiop)
|
|
{
|
|
struct request_queue *q;
|
|
|
|
blkcg_bypass_start();
|
|
spin_lock(&blkio_list_lock);
|
|
|
|
BUG_ON(blkio_policy[blkiop->plid] != blkiop);
|
|
blkio_policy[blkiop->plid] = NULL;
|
|
list_del_init(&blkiop->list);
|
|
|
|
spin_unlock(&blkio_list_lock);
|
|
list_for_each_entry(q, &all_q_list, all_q_node)
|
|
update_root_blkg_pd(q, blkiop->plid);
|
|
blkcg_bypass_end();
|
|
}
|
|
EXPORT_SYMBOL_GPL(blkio_policy_unregister);
|