diff options
| -rw-r--r-- | block/blk-cgroup.c | 228 | ||||
| -rw-r--r-- | block/blk-cgroup.h | 15 | ||||
| -rw-r--r-- | block/blk-throttle.c | 52 | ||||
| -rw-r--r-- | block/cfq-iosched.c | 37 | ||||
| -rw-r--r-- | block/elevator.c | 2 | ||||
| -rw-r--r-- | include/linux/blkdev.h | 1 |
6 files changed, 201 insertions, 134 deletions
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c index d6e4555..d6d59ad 100644 --- a/block/blk-cgroup.c +++ b/block/blk-cgroup.c @@ -54,6 +54,17 @@ struct blkio_cgroup *bio_blkio_cgroup(struct bio *bio) } EXPORT_SYMBOL_GPL(bio_blkio_cgroup); +static bool blkcg_policy_enabled(struct request_queue *q, + const struct blkio_policy_type *pol) +{ + return pol && test_bit(pol->plid, q->blkcg_pols); +} + +static size_t blkg_pd_size(const struct blkio_policy_type *pol) +{ + return sizeof(struct blkg_policy_data) + pol->pdata_size; +} + /** * blkg_free - free a blkg * @blkg: blkg to free @@ -111,12 +122,11 @@ static struct blkio_group *blkg_alloc(struct blkio_cgroup *blkcg, struct blkio_policy_type *pol = blkio_policy[i]; struct blkg_policy_data *pd; - if (!pol) + if (!blkcg_policy_enabled(q, pol)) continue; /* alloc per-policy data and attach it to blkg */ - pd = kzalloc_node(sizeof(*pd) + pol->pdata_size, GFP_ATOMIC, - q->node); + pd = kzalloc_node(blkg_pd_size(pol), GFP_ATOMIC, q->node); if (!pd) { blkg_free(blkg); return NULL; @@ -130,7 +140,7 @@ static struct blkio_group *blkg_alloc(struct blkio_cgroup *blkcg, for (i = 0; i < BLKCG_MAX_POLS; i++) { struct blkio_policy_type *pol = blkio_policy[i]; - if (pol) + if (blkcg_policy_enabled(blkg->q, pol)) pol->ops.blkio_init_group_fn(blkg); } @@ -236,36 +246,6 @@ static void blkg_destroy(struct blkio_group *blkg) 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, - const struct blkio_policy_type *pol) -{ - struct blkio_group *blkg = blkg_lookup(&blkio_root_cgroup, q); - struct blkg_policy_data *pd; - - if (!blkg) - return; - - kfree(blkg->pd[pol->plid]); - blkg->pd[pol->plid] = NULL; - - if (!pol) - return; - - pd = kzalloc(sizeof(*pd) + pol->pdata_size, GFP_KERNEL); - WARN_ON_ONCE(!pd); - - blkg->pd[pol->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 @@ -339,7 +319,8 @@ blkiocg_reset_stats(struct cgroup *cgroup, struct cftype *cftype, u64 val) for (i = 0; i < BLKCG_MAX_POLS; i++) { struct blkio_policy_type *pol = blkio_policy[i]; - if (pol && pol->ops.blkio_reset_group_stats_fn) + if (blkcg_policy_enabled(blkg->q, pol) && + pol->ops.blkio_reset_group_stats_fn) pol->ops.blkio_reset_group_stats_fn(blkg); } } @@ -385,7 +366,7 @@ void blkcg_print_blkgs(struct seq_file *sf, struct blkio_cgroup *blkcg, spin_lock_irq(&blkcg->lock); hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node) - if (blkg->pd[pol->plid]) + if (blkcg_policy_enabled(blkg->q, pol)) total += prfill(sf, blkg->pd[pol->plid]->pdata, data); spin_unlock_irq(&blkcg->lock); @@ -510,7 +491,10 @@ int blkg_conf_prep(struct blkio_cgroup *blkcg, rcu_read_lock(); spin_lock_irq(disk->queue->queue_lock); - blkg = blkg_lookup_create(blkcg, disk->queue, false); + if (blkcg_policy_enabled(disk->queue, pol)) + blkg = blkg_lookup_create(blkcg, disk->queue, false); + else + blkg = ERR_PTR(-EINVAL); if (IS_ERR(blkg)) { ret = PTR_ERR(blkg); @@ -712,30 +696,6 @@ static int blkiocg_can_attach(struct cgroup *cgrp, struct cgroup_taskset *tset) return ret; } -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); -} - struct cgroup_subsys blkio_subsys = { .name = "blkio", .create = blkiocg_create, @@ -749,6 +709,139 @@ struct cgroup_subsys blkio_subsys = { EXPORT_SYMBOL_GPL(blkio_subsys); /** + * 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) +{ + 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, true); + 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(blkcg_activate_policy); + +/** + * 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) +{ + 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); + + 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(blkcg_deactivate_policy); + +/** * blkio_policy_register - register a blkcg policy * @blkiop: blkcg policy to register * @@ -758,7 +851,6 @@ EXPORT_SYMBOL_GPL(blkio_subsys); */ int blkio_policy_register(struct blkio_policy_type *blkiop) { - struct request_queue *q; int i, ret; mutex_lock(&blkcg_pol_mutex); @@ -775,11 +867,6 @@ int blkio_policy_register(struct blkio_policy_type *blkiop) blkiop->plid = i; blkio_policy[i] = blkiop; - blkcg_bypass_start(); - list_for_each_entry(q, &all_q_list, all_q_node) - update_root_blkg_pd(q, blkiop); - blkcg_bypass_end(); - /* everything is in place, add intf files for the new policy */ if (blkiop->cftypes) WARN_ON(cgroup_add_cftypes(&blkio_subsys, blkiop->cftypes)); @@ -798,8 +885,6 @@ EXPORT_SYMBOL_GPL(blkio_policy_register); */ void blkio_policy_unregister(struct blkio_policy_type *blkiop) { - struct request_queue *q; - mutex_lock(&blkcg_pol_mutex); if (WARN_ON(blkio_policy[blkiop->plid] != blkiop)) @@ -811,11 +896,6 @@ void blkio_policy_unregister(struct blkio_policy_type *blkiop) /* unregister and update blkgs */ blkio_policy[blkiop->plid] = NULL; - - blkcg_bypass_start(); - list_for_each_entry(q, &all_q_list, all_q_node) - update_root_blkg_pd(q, blkiop); - blkcg_bypass_end(); out_unlock: mutex_unlock(&blkcg_pol_mutex); } diff --git a/block/blk-cgroup.h b/block/blk-cgroup.h index df1c7b2..66253a7 100644 --- a/block/blk-cgroup.h +++ b/block/blk-cgroup.h @@ -64,6 +64,9 @@ struct blkg_policy_data { /* the blkg this per-policy data belongs to */ struct blkio_group *blkg; + /* used during policy activation */ + struct list_head alloc_node; + /* pol->pdata_size bytes of private data used by policy impl */ char pdata[] __aligned(__alignof__(unsigned long long)); }; @@ -108,9 +111,11 @@ extern void blkcg_exit_queue(struct request_queue *q); /* Blkio controller policy registration */ extern int blkio_policy_register(struct blkio_policy_type *); extern void blkio_policy_unregister(struct blkio_policy_type *); +extern int blkcg_activate_policy(struct request_queue *q, + const struct blkio_policy_type *pol); +extern void blkcg_deactivate_policy(struct request_queue *q, + const struct blkio_policy_type *pol); extern void blkg_destroy_all(struct request_queue *q, bool destroy_root); -extern void update_root_blkg_pd(struct request_queue *q, - const struct blkio_policy_type *pol); void blkcg_print_blkgs(struct seq_file *sf, struct blkio_cgroup *blkcg, u64 (*prfill)(struct seq_file *, void *, int), @@ -325,10 +330,12 @@ static inline void blkcg_drain_queue(struct request_queue *q) { } static inline void blkcg_exit_queue(struct request_queue *q) { } static inline int blkio_policy_register(struct blkio_policy_type *blkiop) { return 0; } static inline void blkio_policy_unregister(struct blkio_policy_type *blkiop) { } +static inline int blkcg_activate_policy(struct request_queue *q, + const struct blkio_policy_type *pol) { return 0; } +static inline void blkcg_deactivate_policy(struct request_queue *q, + const struct blkio_policy_type *pol) { } static inline void blkg_destroy_all(struct request_queue *q, bool destory_root) { } -static inline void update_root_blkg_pd(struct request_queue *q, - const struct blkio_policy_type *pol) { } static inline void *blkg_to_pdata(struct blkio_group *blkg, struct blkio_policy_type *pol) { return NULL; } diff --git a/block/blk-throttle.c b/block/blk-throttle.c index 8c520fa..2fc964e 100644 --- a/block/blk-throttle.c +++ b/block/blk-throttle.c @@ -995,35 +995,31 @@ static int tg_set_conf(struct cgroup *cgrp, struct cftype *cft, const char *buf, struct blkio_cgroup *blkcg = cgroup_to_blkio_cgroup(cgrp); struct blkg_conf_ctx ctx; struct throtl_grp *tg; + struct throtl_data *td; int ret; ret = blkg_conf_prep(blkcg, &blkio_policy_throtl, buf, &ctx); if (ret) return ret; - ret = -EINVAL; tg = blkg_to_tg(ctx.blkg); - if (tg) { - struct throtl_data *td = ctx.blkg->q->td; - - if (!ctx.v) - ctx.v = -1; + td = ctx.blkg->q->td; - if (is_u64) - *(u64 *)((void *)tg + cft->private) = ctx.v; - else - *(unsigned int *)((void *)tg + cft->private) = ctx.v; + if (!ctx.v) + ctx.v = -1; - /* XXX: we don't need the following deferred processing */ - xchg(&tg->limits_changed, true); - xchg(&td->limits_changed, true); - throtl_schedule_delayed_work(td, 0); + if (is_u64) + *(u64 *)((void *)tg + cft->private) = ctx.v; + else + *(unsigned int *)((void *)tg + cft->private) = ctx.v; - ret = 0; - } + /* XXX: we don't need the following deferred processing */ + xchg(&tg->limits_changed, true); + xchg(&td->limits_changed, true); + throtl_schedule_delayed_work(td, 0); blkg_conf_finish(&ctx); - return ret; + return 0; } static int tg_set_conf_u64(struct cgroup *cgrp, struct cftype *cft, @@ -1230,7 +1226,7 @@ void blk_throtl_drain(struct request_queue *q) int blk_throtl_init(struct request_queue *q) { struct throtl_data *td; - struct blkio_group *blkg; + int ret; td = kzalloc_node(sizeof(*td), GFP_KERNEL, q->node); if (!td) @@ -1243,28 +1239,18 @@ int blk_throtl_init(struct request_queue *q) q->td = td; td->queue = q; - /* alloc and init root group. */ - rcu_read_lock(); - spin_lock_irq(q->queue_lock); - - blkg = blkg_lookup_create(&blkio_root_cgroup, q, true); - if (!IS_ERR(blkg)) - q->root_blkg = blkg; - - spin_unlock_irq(q->queue_lock); - rcu_read_unlock(); - - if (!q->root_blkg) { + /* activate policy */ + ret = blkcg_activate_policy(q, &blkio_policy_throtl); + if (ret) kfree(td); - return -ENOMEM; - } - return 0; + return ret; } void blk_throtl_exit(struct request_queue *q) { BUG_ON(!q->td); throtl_shutdown_wq(q); + blkcg_deactivate_policy(q, &blkio_policy_throtl); kfree(q->td); } diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c index 86440e0..0203652 100644 --- a/block/cfq-iosched.c +++ b/block/cfq-iosched.c @@ -1406,8 +1406,7 @@ static int cfqg_set_weight_device(struct cgroup *cgrp, struct cftype *cft, ret = -EINVAL; cfqg = blkg_to_cfqg(ctx.blkg); - if (cfqg && (!ctx.v || (ctx.v >= CFQ_WEIGHT_MIN && - ctx.v <= CFQ_WEIGHT_MAX))) { + if (!ctx.v || (ctx.v >= CFQ_WEIGHT_MIN && ctx.v <= CFQ_WEIGHT_MAX)) { cfqg->dev_weight = ctx.v; cfqg->new_weight = cfqg->dev_weight ?: blkcg->cfq_weight; ret = 0; @@ -3938,7 +3937,7 @@ static void cfq_exit_queue(struct elevator_queue *e) #ifndef CONFIG_CFQ_GROUP_IOSCHED kfree(cfqd->root_group); #endif - update_root_blkg_pd(q, &blkio_policy_cfq); + blkcg_deactivate_policy(q, &blkio_policy_cfq); kfree(cfqd); } @@ -3946,7 +3945,7 @@ static int cfq_init_queue(struct request_queue *q) { struct cfq_data *cfqd; struct blkio_group *blkg __maybe_unused; - int i; + int i, ret; cfqd = kmalloc_node(sizeof(*cfqd), GFP_KERNEL | __GFP_ZERO, q->node); if (!cfqd) @@ -3960,28 +3959,20 @@ static int cfq_init_queue(struct request_queue *q) /* Init root group and prefer root group over other groups by default */ #ifdef CONFIG_CFQ_GROUP_IOSCHED - rcu_read_lock(); - spin_lock_irq(q->queue_lock); - - blkg = blkg_lookup_create(&blkio_root_cgroup, q, true); - if (!IS_ERR(blkg)) { - q->root_blkg = blkg; - cfqd->root_group = blkg_to_cfqg(blkg); - } + ret = blkcg_activate_policy(q, &blkio_policy_cfq); + if (ret) + goto out_free; - spin_unlock_irq(q->queue_lock); - rcu_read_unlock(); + cfqd->root_group = blkg_to_cfqg(q->root_blkg); #else + ret = -ENOMEM; cfqd->root_group = kzalloc_node(sizeof(*cfqd->root_group), GFP_KERNEL, cfqd->queue->node); - if (cfqd->root_group) - cfq_init_cfqg_base(cfqd->root_group); -#endif - if (!cfqd->root_group) { - kfree(cfqd); - return -ENOMEM; - } + if (!cfqd->root_group) + goto out_free; + cfq_init_cfqg_base(cfqd->root_group); +#endif cfqd->root_group->weight = 2 * CFQ_WEIGHT_DEFAULT; /* @@ -4031,6 +4022,10 @@ static int cfq_init_queue(struct request_queue *q) */ cfqd->last_delayed_sync = jiffies - HZ; return 0; + +out_free: + kfree(cfqd); + return ret; } /* diff --git a/block/elevator.c b/block/elevator.c index be3ab6d..6a55d41 100644 --- a/block/elevator.c +++ b/block/elevator.c @@ -896,8 +896,6 @@ static int elevator_switch(struct request_queue *q, struct elevator_type *new_e) ioc_clear_queue(q); spin_unlock_irq(q->queue_lock); - blkg_destroy_all(q, false); - /* allocate, init and register new elevator */ err = -ENOMEM; q->elevator = elevator_alloc(q, new_e); diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index b01c377..68720ab 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -370,6 +370,7 @@ struct request_queue { struct list_head icq_list; #ifdef CONFIG_BLK_CGROUP + DECLARE_BITMAP (blkcg_pols, BLKCG_MAX_POLS); struct blkio_group *root_blkg; struct list_head blkg_list; #endif |
