diff options
| -rw-r--r-- | block/blk-cgroup.c | 78 | ||||
| -rw-r--r-- | include/linux/blk-cgroup.h | 1 |
2 files changed, 63 insertions, 16 deletions
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c index c2033a232a44..1c16694ae145 100644 --- a/block/blk-cgroup.c +++ b/block/blk-cgroup.c @@ -307,11 +307,28 @@ struct blkcg_gq *blkg_lookup_create(struct blkcg *blkcg, } } +static void blkg_pd_offline(struct blkcg_gq *blkg) +{ + int i; + + lockdep_assert_held(blkg->q->queue_lock); + lockdep_assert_held(&blkg->blkcg->lock); + + for (i = 0; i < BLKCG_MAX_POLS; i++) { + struct blkcg_policy *pol = blkcg_policy[i]; + + if (blkg->pd[i] && !blkg->pd[i]->offline && + pol->pd_offline_fn) { + pol->pd_offline_fn(blkg->pd[i]); + blkg->pd[i]->offline = true; + } + } +} + static void blkg_destroy(struct blkcg_gq *blkg) { struct blkcg *blkcg = blkg->blkcg; struct blkcg_gq *parent = blkg->parent; - int i; lockdep_assert_held(blkg->q->queue_lock); lockdep_assert_held(&blkcg->lock); @@ -320,13 +337,6 @@ static void blkg_destroy(struct blkcg_gq *blkg) WARN_ON_ONCE(list_empty(&blkg->q_node)); WARN_ON_ONCE(hlist_unhashed(&blkg->blkcg_node)); - for (i = 0; i < BLKCG_MAX_POLS; i++) { - struct blkcg_policy *pol = blkcg_policy[i]; - - if (blkg->pd[i] && pol->pd_offline_fn) - pol->pd_offline_fn(blkg->pd[i]); - } - if (parent) { blkg_rwstat_add_aux(&parent->stat_bytes, &blkg->stat_bytes); blkg_rwstat_add_aux(&parent->stat_ios, &blkg->stat_ios); @@ -369,6 +379,7 @@ static void blkg_destroy_all(struct request_queue *q) struct blkcg *blkcg = blkg->blkcg; spin_lock(&blkcg->lock); + blkg_pd_offline(blkg); blkg_destroy(blkg); spin_unlock(&blkcg->lock); } @@ -995,25 +1006,25 @@ static struct cftype blkcg_legacy_files[] = { * @css: css of interest * * This function is called when @css is about to go away and responsible - * for shooting down all blkgs associated with @css. 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. + * for offlining all blkgs pd and killing all wbs associated with @css. + * blkgs pd offline should be done 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 void blkcg_css_offline(struct cgroup_subsys_state *css) { struct blkcg *blkcg = css_to_blkcg(css); + struct blkcg_gq *blkg; spin_lock_irq(&blkcg->lock); - while (!hlist_empty(&blkcg->blkg_list)) { - struct blkcg_gq *blkg = hlist_entry(blkcg->blkg_list.first, - struct blkcg_gq, blkcg_node); + hlist_for_each_entry(blkg, &blkcg->blkg_list, blkcg_node) { struct request_queue *q = blkg->q; if (spin_trylock(q->queue_lock)) { - blkg_destroy(blkg); + blkg_pd_offline(blkg); spin_unlock(q->queue_lock); } else { spin_unlock_irq(&blkcg->lock); @@ -1027,11 +1038,43 @@ static void blkcg_css_offline(struct cgroup_subsys_state *css) wb_blkcg_offline(blkcg); } +/** + * blkcg_destroy_all_blkgs - destroy all blkgs associated with a blkcg + * @blkcg: blkcg of interest + * + * This function is called when blkcg css is about to free and responsible for + * destroying all blkgs associated with @blkcg. + * 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. + */ +static void blkcg_destroy_all_blkgs(struct blkcg *blkcg) +{ + spin_lock_irq(&blkcg->lock); + while (!hlist_empty(&blkcg->blkg_list)) { + struct blkcg_gq *blkg = hlist_entry(blkcg->blkg_list.first, + struct blkcg_gq, + 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); + } + } + spin_unlock_irq(&blkcg->lock); +} + static void blkcg_css_free(struct cgroup_subsys_state *css) { struct blkcg *blkcg = css_to_blkcg(css); int i; + blkcg_destroy_all_blkgs(blkcg); + mutex_lock(&blkcg_pol_mutex); list_del(&blkcg->all_blkcgs_node); @@ -1371,8 +1414,11 @@ void blkcg_deactivate_policy(struct request_queue *q, spin_lock(&blkg->blkcg->lock); if (blkg->pd[pol->plid]) { - if (pol->pd_offline_fn) + if (!blkg->pd[pol->plid]->offline && + pol->pd_offline_fn) { pol->pd_offline_fn(blkg->pd[pol->plid]); + blkg->pd[pol->plid]->offline = true; + } pol->pd_free_fn(blkg->pd[pol->plid]); blkg->pd[pol->plid] = NULL; } diff --git a/include/linux/blk-cgroup.h b/include/linux/blk-cgroup.h index 69bea82ebeb1..6c666fd7de3c 100644 --- a/include/linux/blk-cgroup.h +++ b/include/linux/blk-cgroup.h @@ -88,6 +88,7 @@ struct blkg_policy_data { /* the blkg and policy id this per-policy data belongs to */ struct blkcg_gq *blkg; int plid; + bool offline; }; /* |