From eea8f41cc58849e354ecf8b95bd7f806e1d1f703 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Fri, 22 May 2015 17:13:17 -0400 Subject: blkcg: move block/blk-cgroup.h to include/linux/blk-cgroup.h cgroup aware writeback support will require exposing some of blkcg details. In preprataion, move block/blk-cgroup.h to include/linux/blk-cgroup.h. This patch is pure file move. Signed-off-by: Tejun Heo Cc: Vivek Goyal Signed-off-by: Jens Axboe --- block/blk-cgroup.c | 2 +- block/blk-cgroup.h | 603 --------------------------------------------------- block/blk-core.c | 2 +- block/blk-sysfs.c | 2 +- block/blk-throttle.c | 2 +- block/cfq-iosched.c | 2 +- block/elevator.c | 2 +- 7 files changed, 6 insertions(+), 609 deletions(-) delete mode 100644 block/blk-cgroup.h (limited to 'block') diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c index 0ac817b..c3226ce 100644 --- a/block/blk-cgroup.c +++ b/block/blk-cgroup.c @@ -19,7 +19,7 @@ #include #include #include -#include "blk-cgroup.h" +#include #include "blk.h" #define MAX_KEY_LEN 100 diff --git a/block/blk-cgroup.h b/block/blk-cgroup.h deleted file mode 100644 index c567865..0000000 --- a/block/blk-cgroup.h +++ /dev/null @@ -1,603 +0,0 @@ -#ifndef _BLK_CGROUP_H -#define _BLK_CGROUP_H -/* - * Common Block IO controller cgroup interface - * - * Based on ideas and code from CFQ, CFS and BFQ: - * Copyright (C) 2003 Jens Axboe - * - * Copyright (C) 2008 Fabio Checconi - * Paolo Valente - * - * Copyright (C) 2009 Vivek Goyal - * Nauman Rafique - */ - -#include -#include -#include -#include -#include -#include - -/* Max limits for throttle policy */ -#define THROTL_IOPS_MAX UINT_MAX - -/* CFQ specific, out here for blkcg->cfq_weight */ -#define CFQ_WEIGHT_MIN 10 -#define CFQ_WEIGHT_MAX 1000 -#define CFQ_WEIGHT_DEFAULT 500 - -#ifdef CONFIG_BLK_CGROUP - -enum blkg_rwstat_type { - BLKG_RWSTAT_READ, - BLKG_RWSTAT_WRITE, - BLKG_RWSTAT_SYNC, - BLKG_RWSTAT_ASYNC, - - BLKG_RWSTAT_NR, - BLKG_RWSTAT_TOTAL = BLKG_RWSTAT_NR, -}; - -struct blkcg_gq; - -struct blkcg { - struct cgroup_subsys_state css; - spinlock_t lock; - - struct radix_tree_root blkg_tree; - struct blkcg_gq *blkg_hint; - struct hlist_head blkg_list; - - /* TODO: per-policy storage in blkcg */ - unsigned int cfq_weight; /* belongs to cfq */ - unsigned int cfq_leaf_weight; -}; - -struct blkg_stat { - struct u64_stats_sync syncp; - uint64_t cnt; -}; - -struct blkg_rwstat { - struct u64_stats_sync syncp; - uint64_t cnt[BLKG_RWSTAT_NR]; -}; - -/* - * A blkcg_gq (blkg) is association between a block cgroup (blkcg) and a - * request_queue (q). This is used by blkcg policies which need to track - * information per blkcg - q pair. - * - * There can be multiple active blkcg policies and each has its private - * data on each blkg, the size of which is determined by - * blkcg_policy->pd_size. blkcg core allocates and frees such areas - * together with blkg and invokes pd_init/exit_fn() methods. - * - * Such private data must embed struct blkg_policy_data (pd) at the - * beginning and pd_size can't be smaller than pd. - */ -struct blkg_policy_data { - /* the blkg and policy id this per-policy data belongs to */ - struct blkcg_gq *blkg; - int plid; - - /* used during policy activation */ - struct list_head alloc_node; -}; - -/* association between a blk cgroup and a request queue */ -struct blkcg_gq { - /* Pointer to the associated request_queue */ - struct request_queue *q; - struct list_head q_node; - struct hlist_node blkcg_node; - struct blkcg *blkcg; - - /* all non-root blkcg_gq's are guaranteed to have access to parent */ - struct blkcg_gq *parent; - - /* request allocation list for this blkcg-q pair */ - struct request_list rl; - - /* reference count */ - atomic_t refcnt; - - /* is this blkg online? protected by both blkcg and q locks */ - bool online; - - struct blkg_policy_data *pd[BLKCG_MAX_POLS]; - - struct rcu_head rcu_head; -}; - -typedef void (blkcg_pol_init_pd_fn)(struct blkcg_gq *blkg); -typedef void (blkcg_pol_online_pd_fn)(struct blkcg_gq *blkg); -typedef void (blkcg_pol_offline_pd_fn)(struct blkcg_gq *blkg); -typedef void (blkcg_pol_exit_pd_fn)(struct blkcg_gq *blkg); -typedef void (blkcg_pol_reset_pd_stats_fn)(struct blkcg_gq *blkg); - -struct blkcg_policy { - int plid; - /* policy specific private data size */ - size_t pd_size; - /* cgroup files for the policy */ - struct cftype *cftypes; - - /* operations */ - blkcg_pol_init_pd_fn *pd_init_fn; - blkcg_pol_online_pd_fn *pd_online_fn; - blkcg_pol_offline_pd_fn *pd_offline_fn; - blkcg_pol_exit_pd_fn *pd_exit_fn; - blkcg_pol_reset_pd_stats_fn *pd_reset_stats_fn; -}; - -extern struct blkcg blkcg_root; - -struct blkcg_gq *blkg_lookup(struct blkcg *blkcg, struct request_queue *q); -struct blkcg_gq *blkg_lookup_create(struct blkcg *blkcg, - struct request_queue *q); -int blkcg_init_queue(struct request_queue *q); -void blkcg_drain_queue(struct request_queue *q); -void blkcg_exit_queue(struct request_queue *q); - -/* Blkio controller policy registration */ -int blkcg_policy_register(struct blkcg_policy *pol); -void blkcg_policy_unregister(struct blkcg_policy *pol); -int blkcg_activate_policy(struct request_queue *q, - const struct blkcg_policy *pol); -void blkcg_deactivate_policy(struct request_queue *q, - const struct blkcg_policy *pol); - -void blkcg_print_blkgs(struct seq_file *sf, struct blkcg *blkcg, - u64 (*prfill)(struct seq_file *, - struct blkg_policy_data *, int), - const struct blkcg_policy *pol, int data, - bool show_total); -u64 __blkg_prfill_u64(struct seq_file *sf, struct blkg_policy_data *pd, u64 v); -u64 __blkg_prfill_rwstat(struct seq_file *sf, struct blkg_policy_data *pd, - const struct blkg_rwstat *rwstat); -u64 blkg_prfill_stat(struct seq_file *sf, struct blkg_policy_data *pd, int off); -u64 blkg_prfill_rwstat(struct seq_file *sf, struct blkg_policy_data *pd, - int off); - -u64 blkg_stat_recursive_sum(struct blkg_policy_data *pd, int off); -struct blkg_rwstat blkg_rwstat_recursive_sum(struct blkg_policy_data *pd, - int off); - -struct blkg_conf_ctx { - struct gendisk *disk; - struct blkcg_gq *blkg; - u64 v; -}; - -int blkg_conf_prep(struct blkcg *blkcg, const struct blkcg_policy *pol, - const char *input, struct blkg_conf_ctx *ctx); -void blkg_conf_finish(struct blkg_conf_ctx *ctx); - - -static inline struct blkcg *css_to_blkcg(struct cgroup_subsys_state *css) -{ - return css ? container_of(css, struct blkcg, css) : NULL; -} - -static inline struct blkcg *task_blkcg(struct task_struct *tsk) -{ - return css_to_blkcg(task_css(tsk, blkio_cgrp_id)); -} - -static inline struct blkcg *bio_blkcg(struct bio *bio) -{ - if (bio && bio->bi_css) - return css_to_blkcg(bio->bi_css); - return task_blkcg(current); -} - -/** - * blkcg_parent - get the parent of a blkcg - * @blkcg: blkcg of interest - * - * Return the parent blkcg of @blkcg. Can be called anytime. - */ -static inline struct blkcg *blkcg_parent(struct blkcg *blkcg) -{ - return css_to_blkcg(blkcg->css.parent); -} - -/** - * blkg_to_pdata - get policy private data - * @blkg: blkg of interest - * @pol: policy of interest - * - * Return pointer to private data associated with the @blkg-@pol pair. - */ -static inline struct blkg_policy_data *blkg_to_pd(struct blkcg_gq *blkg, - struct blkcg_policy *pol) -{ - return blkg ? blkg->pd[pol->plid] : NULL; -} - -/** - * pdata_to_blkg - get blkg associated with policy private data - * @pd: policy private data of interest - * - * @pd is policy private data. Determine the blkg it's associated with. - */ -static inline struct blkcg_gq *pd_to_blkg(struct blkg_policy_data *pd) -{ - return pd ? pd->blkg : NULL; -} - -/** - * blkg_path - format cgroup path of blkg - * @blkg: blkg of interest - * @buf: target buffer - * @buflen: target buffer length - * - * Format the path of the cgroup of @blkg into @buf. - */ -static inline int blkg_path(struct blkcg_gq *blkg, char *buf, int buflen) -{ - char *p; - - p = cgroup_path(blkg->blkcg->css.cgroup, buf, buflen); - if (!p) { - strncpy(buf, "", buflen); - return -ENAMETOOLONG; - } - - memmove(buf, p, buf + buflen - p); - return 0; -} - -/** - * blkg_get - get a blkg reference - * @blkg: blkg to get - * - * The caller should be holding an existing reference. - */ -static inline void blkg_get(struct blkcg_gq *blkg) -{ - WARN_ON_ONCE(atomic_read(&blkg->refcnt) <= 0); - atomic_inc(&blkg->refcnt); -} - -void __blkg_release_rcu(struct rcu_head *rcu); - -/** - * blkg_put - put a blkg reference - * @blkg: blkg to put - */ -static inline void blkg_put(struct blkcg_gq *blkg) -{ - WARN_ON_ONCE(atomic_read(&blkg->refcnt) <= 0); - if (atomic_dec_and_test(&blkg->refcnt)) - call_rcu(&blkg->rcu_head, __blkg_release_rcu); -} - -struct blkcg_gq *__blkg_lookup(struct blkcg *blkcg, struct request_queue *q, - bool update_hint); - -/** - * blkg_for_each_descendant_pre - pre-order walk of a blkg's descendants - * @d_blkg: loop cursor pointing to the current descendant - * @pos_css: used for iteration - * @p_blkg: target blkg to walk descendants of - * - * Walk @c_blkg through the descendants of @p_blkg. Must be used with RCU - * read locked. If called under either blkcg or queue lock, the iteration - * is guaranteed to include all and only online blkgs. The caller may - * update @pos_css by calling css_rightmost_descendant() to skip subtree. - * @p_blkg is included in the iteration and the first node to be visited. - */ -#define blkg_for_each_descendant_pre(d_blkg, pos_css, p_blkg) \ - css_for_each_descendant_pre((pos_css), &(p_blkg)->blkcg->css) \ - if (((d_blkg) = __blkg_lookup(css_to_blkcg(pos_css), \ - (p_blkg)->q, false))) - -/** - * blkg_for_each_descendant_post - post-order walk of a blkg's descendants - * @d_blkg: loop cursor pointing to the current descendant - * @pos_css: used for iteration - * @p_blkg: target blkg to walk descendants of - * - * Similar to blkg_for_each_descendant_pre() but performs post-order - * traversal instead. Synchronization rules are the same. @p_blkg is - * included in the iteration and the last node to be visited. - */ -#define blkg_for_each_descendant_post(d_blkg, pos_css, p_blkg) \ - css_for_each_descendant_post((pos_css), &(p_blkg)->blkcg->css) \ - if (((d_blkg) = __blkg_lookup(css_to_blkcg(pos_css), \ - (p_blkg)->q, false))) - -/** - * blk_get_rl - get request_list to use - * @q: request_queue of interest - * @bio: bio which will be attached to the allocated request (may be %NULL) - * - * The caller wants to allocate a request from @q to use for @bio. Find - * the request_list to use and obtain a reference on it. Should be called - * under queue_lock. This function is guaranteed to return non-%NULL - * request_list. - */ -static inline struct request_list *blk_get_rl(struct request_queue *q, - struct bio *bio) -{ - struct blkcg *blkcg; - struct blkcg_gq *blkg; - - rcu_read_lock(); - - blkcg = bio_blkcg(bio); - - /* bypass blkg lookup and use @q->root_rl directly for root */ - if (blkcg == &blkcg_root) - goto root_rl; - - /* - * Try to use blkg->rl. blkg lookup may fail under memory pressure - * or if either the blkcg or queue is going away. Fall back to - * root_rl in such cases. - */ - blkg = blkg_lookup_create(blkcg, q); - if (unlikely(IS_ERR(blkg))) - goto root_rl; - - blkg_get(blkg); - rcu_read_unlock(); - return &blkg->rl; -root_rl: - rcu_read_unlock(); - return &q->root_rl; -} - -/** - * blk_put_rl - put request_list - * @rl: request_list to put - * - * Put the reference acquired by blk_get_rl(). Should be called under - * queue_lock. - */ -static inline void blk_put_rl(struct request_list *rl) -{ - /* root_rl may not have blkg set */ - if (rl->blkg && rl->blkg->blkcg != &blkcg_root) - blkg_put(rl->blkg); -} - -/** - * blk_rq_set_rl - associate a request with a request_list - * @rq: request of interest - * @rl: target request_list - * - * Associate @rq with @rl so that accounting and freeing can know the - * request_list @rq came from. - */ -static inline void blk_rq_set_rl(struct request *rq, struct request_list *rl) -{ - rq->rl = rl; -} - -/** - * blk_rq_rl - return the request_list a request came from - * @rq: request of interest - * - * Return the request_list @rq is allocated from. - */ -static inline struct request_list *blk_rq_rl(struct request *rq) -{ - return rq->rl; -} - -struct request_list *__blk_queue_next_rl(struct request_list *rl, - struct request_queue *q); -/** - * blk_queue_for_each_rl - iterate through all request_lists of a request_queue - * - * Should be used under queue_lock. - */ -#define blk_queue_for_each_rl(rl, q) \ - for ((rl) = &(q)->root_rl; (rl); (rl) = __blk_queue_next_rl((rl), (q))) - -static inline void blkg_stat_init(struct blkg_stat *stat) -{ - u64_stats_init(&stat->syncp); -} - -/** - * blkg_stat_add - add a value to a blkg_stat - * @stat: target blkg_stat - * @val: value to add - * - * Add @val to @stat. The caller is responsible for synchronizing calls to - * this function. - */ -static inline void blkg_stat_add(struct blkg_stat *stat, uint64_t val) -{ - u64_stats_update_begin(&stat->syncp); - stat->cnt += val; - u64_stats_update_end(&stat->syncp); -} - -/** - * blkg_stat_read - read the current value of a blkg_stat - * @stat: blkg_stat to read - * - * Read the current value of @stat. This function can be called without - * synchroniztion and takes care of u64 atomicity. - */ -static inline uint64_t blkg_stat_read(struct blkg_stat *stat) -{ - unsigned int start; - uint64_t v; - - do { - start = u64_stats_fetch_begin_irq(&stat->syncp); - v = stat->cnt; - } while (u64_stats_fetch_retry_irq(&stat->syncp, start)); - - return v; -} - -/** - * blkg_stat_reset - reset a blkg_stat - * @stat: blkg_stat to reset - */ -static inline void blkg_stat_reset(struct blkg_stat *stat) -{ - stat->cnt = 0; -} - -/** - * blkg_stat_merge - merge a blkg_stat into another - * @to: the destination blkg_stat - * @from: the source - * - * Add @from's count to @to. - */ -static inline void blkg_stat_merge(struct blkg_stat *to, struct blkg_stat *from) -{ - blkg_stat_add(to, blkg_stat_read(from)); -} - -static inline void blkg_rwstat_init(struct blkg_rwstat *rwstat) -{ - u64_stats_init(&rwstat->syncp); -} - -/** - * blkg_rwstat_add - add a value to a blkg_rwstat - * @rwstat: target blkg_rwstat - * @rw: mask of REQ_{WRITE|SYNC} - * @val: value to add - * - * Add @val to @rwstat. The counters are chosen according to @rw. The - * caller is responsible for synchronizing calls to this function. - */ -static inline void blkg_rwstat_add(struct blkg_rwstat *rwstat, - int rw, uint64_t val) -{ - u64_stats_update_begin(&rwstat->syncp); - - if (rw & REQ_WRITE) - rwstat->cnt[BLKG_RWSTAT_WRITE] += val; - else - rwstat->cnt[BLKG_RWSTAT_READ] += val; - if (rw & REQ_SYNC) - rwstat->cnt[BLKG_RWSTAT_SYNC] += val; - else - rwstat->cnt[BLKG_RWSTAT_ASYNC] += val; - - u64_stats_update_end(&rwstat->syncp); -} - -/** - * blkg_rwstat_read - read the current values of a blkg_rwstat - * @rwstat: blkg_rwstat to read - * - * Read the current snapshot of @rwstat and return it as the return value. - * This function can be called without synchronization and takes care of - * u64 atomicity. - */ -static inline struct blkg_rwstat blkg_rwstat_read(struct blkg_rwstat *rwstat) -{ - unsigned int start; - struct blkg_rwstat tmp; - - do { - start = u64_stats_fetch_begin_irq(&rwstat->syncp); - tmp = *rwstat; - } while (u64_stats_fetch_retry_irq(&rwstat->syncp, start)); - - return tmp; -} - -/** - * blkg_rwstat_total - read the total count of a blkg_rwstat - * @rwstat: blkg_rwstat to read - * - * Return the total count of @rwstat regardless of the IO direction. This - * function can be called without synchronization and takes care of u64 - * atomicity. - */ -static inline uint64_t blkg_rwstat_total(struct blkg_rwstat *rwstat) -{ - struct blkg_rwstat tmp = blkg_rwstat_read(rwstat); - - return tmp.cnt[BLKG_RWSTAT_READ] + tmp.cnt[BLKG_RWSTAT_WRITE]; -} - -/** - * blkg_rwstat_reset - reset a blkg_rwstat - * @rwstat: blkg_rwstat to reset - */ -static inline void blkg_rwstat_reset(struct blkg_rwstat *rwstat) -{ - memset(rwstat->cnt, 0, sizeof(rwstat->cnt)); -} - -/** - * blkg_rwstat_merge - merge a blkg_rwstat into another - * @to: the destination blkg_rwstat - * @from: the source - * - * Add @from's counts to @to. - */ -static inline void blkg_rwstat_merge(struct blkg_rwstat *to, - struct blkg_rwstat *from) -{ - struct blkg_rwstat v = blkg_rwstat_read(from); - int i; - - u64_stats_update_begin(&to->syncp); - for (i = 0; i < BLKG_RWSTAT_NR; i++) - to->cnt[i] += v.cnt[i]; - u64_stats_update_end(&to->syncp); -} - -#else /* CONFIG_BLK_CGROUP */ - -struct cgroup; -struct blkcg; - -struct blkg_policy_data { -}; - -struct blkcg_gq { -}; - -struct blkcg_policy { -}; - -static inline struct blkcg_gq *blkg_lookup(struct blkcg *blkcg, void *key) { return NULL; } -static inline int blkcg_init_queue(struct request_queue *q) { return 0; } -static inline void blkcg_drain_queue(struct request_queue *q) { } -static inline void blkcg_exit_queue(struct request_queue *q) { } -static inline int blkcg_policy_register(struct blkcg_policy *pol) { return 0; } -static inline void blkcg_policy_unregister(struct blkcg_policy *pol) { } -static inline int blkcg_activate_policy(struct request_queue *q, - const struct blkcg_policy *pol) { return 0; } -static inline void blkcg_deactivate_policy(struct request_queue *q, - const struct blkcg_policy *pol) { } - -static inline struct blkcg *bio_blkcg(struct bio *bio) { return NULL; } - -static inline struct blkg_policy_data *blkg_to_pd(struct blkcg_gq *blkg, - struct blkcg_policy *pol) { return NULL; } -static inline struct blkcg_gq *pd_to_blkg(struct blkg_policy_data *pd) { return NULL; } -static inline char *blkg_path(struct blkcg_gq *blkg) { return NULL; } -static inline void blkg_get(struct blkcg_gq *blkg) { } -static inline void blkg_put(struct blkcg_gq *blkg) { } - -static inline struct request_list *blk_get_rl(struct request_queue *q, - struct bio *bio) { return &q->root_rl; } -static inline void blk_put_rl(struct request_list *rl) { } -static inline void blk_rq_set_rl(struct request *rq, struct request_list *rl) { } -static inline struct request_list *blk_rq_rl(struct request *rq) { return &rq->q->root_rl; } - -#define blk_queue_for_each_rl(rl, q) \ - for ((rl) = &(q)->root_rl; (rl); (rl) = NULL) - -#endif /* CONFIG_BLK_CGROUP */ -#endif /* _BLK_CGROUP_H */ diff --git a/block/blk-core.c b/block/blk-core.c index aa819a5..4afac14d 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -32,12 +32,12 @@ #include #include #include +#include #define CREATE_TRACE_POINTS #include #include "blk.h" -#include "blk-cgroup.h" #include "blk-mq.h" EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_remap); diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c index faaf36a..5677eb7 100644 --- a/block/blk-sysfs.c +++ b/block/blk-sysfs.c @@ -8,9 +8,9 @@ #include #include #include +#include #include "blk.h" -#include "blk-cgroup.h" #include "blk-mq.h" struct queue_sysfs_entry { diff --git a/block/blk-throttle.c b/block/blk-throttle.c index 5b9c6d5..b231935 100644 --- a/block/blk-throttle.c +++ b/block/blk-throttle.c @@ -9,7 +9,7 @@ #include #include #include -#include "blk-cgroup.h" +#include #include "blk.h" /* Max dispatch from a group in 1 round */ diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c index 5da8e6e..bc8f429 100644 --- a/block/cfq-iosched.c +++ b/block/cfq-iosched.c @@ -14,8 +14,8 @@ #include #include #include +#include #include "blk.h" -#include "blk-cgroup.h" /* * tunables diff --git a/block/elevator.c b/block/elevator.c index 59794d0..3bbb48f 100644 --- a/block/elevator.c +++ b/block/elevator.c @@ -35,11 +35,11 @@ #include #include #include +#include #include #include "blk.h" -#include "blk-cgroup.h" static DEFINE_SPINLOCK(elv_list_lock); static LIST_HEAD(elv_list); -- cgit v1.1 From ec13b1d6f0a0457312e615335ce8ceb07da50a11 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Fri, 22 May 2015 17:13:19 -0400 Subject: blkcg: always create the blkcg_gq for the root blkcg Currently, blkcg does a minor optimization where the root blkcg is created when the first blkcg policy is activated on a queue and destroyed on the deactivation of the last. On systems where blkcg is configured but not used, this saves one blkcg_gq struct per queue. On systems where blkcg is actually used, there's no difference. The only case where this can lead to any meaninful, albeit still minute, save in memory consumption is when all blkcg policies are deactivated after being widely used in the system, which is a hihgly unlikely scenario. The conditional existence of root blkcg_gq has already created several bugs in blkcg and became an issue once again for the new per-cgroup wb_congested mechanism for cgroup writeback support leading to a NULL dereference when no blkcg policy is active. This is really not worth bothering with. This patch makes blkcg always allocate and link the root blkcg_gq and release it only on queue destruction. Signed-off-by: Tejun Heo Reported-by: Fengguang Wu Signed-off-by: Jens Axboe --- block/blk-cgroup.c | 96 +++++++++++++++++++++++------------------------------- 1 file changed, 41 insertions(+), 55 deletions(-) (limited to 'block') diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c index c3226ce..2a4f77f 100644 --- a/block/blk-cgroup.c +++ b/block/blk-cgroup.c @@ -235,13 +235,8 @@ static struct blkcg_gq *blkg_create(struct blkcg *blkcg, blkg->online = true; spin_unlock(&blkcg->lock); - if (!ret) { - if (blkcg == &blkcg_root) { - q->root_blkg = blkg; - q->root_rl.blkg = blkg; - } + if (!ret) return blkg; - } /* @blkg failed fully initialized, use the usual release path */ blkg_put(blkg); @@ -340,15 +335,6 @@ static void blkg_destroy(struct blkcg_gq *blkg) rcu_assign_pointer(blkcg->blkg_hint, NULL); /* - * If root blkg is destroyed. Just clear the pointer since root_rl - * does not take reference on root blkg. - */ - if (blkcg == &blkcg_root) { - blkg->q->root_blkg = NULL; - blkg->q->root_rl.blkg = NULL; - } - - /* * Put the reference taken at the time of creation so that when all * queues are gone, group can be destroyed. */ @@ -855,9 +841,45 @@ done: */ int blkcg_init_queue(struct request_queue *q) { - might_sleep(); + struct blkcg_gq *new_blkg, *blkg; + bool preloaded; + int ret; + + new_blkg = blkg_alloc(&blkcg_root, q, GFP_KERNEL); + if (!new_blkg) + return -ENOMEM; + + preloaded = !radix_tree_preload(GFP_KERNEL); - return blk_throtl_init(q); + /* + * Make sure the root blkg exists and count the existing blkgs. As + * @q is bypassing at this point, blkg_lookup_create() can't be + * used. Open code insertion. + */ + rcu_read_lock(); + spin_lock_irq(q->queue_lock); + blkg = blkg_create(&blkcg_root, q, new_blkg); + spin_unlock_irq(q->queue_lock); + rcu_read_unlock(); + + if (preloaded) + radix_tree_preload_end(); + + if (IS_ERR(blkg)) { + kfree(new_blkg); + return PTR_ERR(blkg); + } + + q->root_blkg = blkg; + q->root_rl.blkg = blkg; + + ret = blk_throtl_init(q); + if (ret) { + spin_lock_irq(q->queue_lock); + blkg_destroy_all(q); + spin_unlock_irq(q->queue_lock); + } + return ret; } /** @@ -958,52 +980,20 @@ int blkcg_activate_policy(struct request_queue *q, const struct blkcg_policy *pol) { LIST_HEAD(pds); - struct blkcg_gq *blkg, *new_blkg; + struct blkcg_gq *blkg; struct blkg_policy_data *pd, *n; int cnt = 0, ret; - bool preloaded; if (blkcg_policy_enabled(q, pol)) return 0; - /* preallocations for root blkg */ - new_blkg = blkg_alloc(&blkcg_root, q, GFP_KERNEL); - if (!new_blkg) - return -ENOMEM; - + /* count and allocate policy_data for all existing blkgs */ blk_queue_bypass_start(q); - - preloaded = !radix_tree_preload(GFP_KERNEL); - - /* - * Make sure the root blkg exists and count the existing blkgs. As - * @q is bypassing at this point, blkg_lookup_create() can't be - * used. Open code it. - */ spin_lock_irq(q->queue_lock); - - rcu_read_lock(); - blkg = __blkg_lookup(&blkcg_root, q, false); - if (blkg) - blkg_free(new_blkg); - else - blkg = blkg_create(&blkcg_root, q, new_blkg); - rcu_read_unlock(); - - if (preloaded) - radix_tree_preload_end(); - - if (IS_ERR(blkg)) { - ret = PTR_ERR(blkg); - goto out_unlock; - } - 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(pol->pd_size, GFP_KERNEL, q->node); if (!pd) { @@ -1072,10 +1062,6 @@ void blkcg_deactivate_policy(struct request_queue *q, __clear_bit(pol->plid, q->blkcg_pols); - /* if no policy is left, no need for blkgs - shoot them down */ - if (bitmap_empty(q->blkcg_pols, BLKCG_MAX_POLS)) - blkg_destroy_all(q); - list_for_each_entry(blkg, &q->blkg_list, q_node) { /* grab blkcg lock too while removing @pd from @blkg */ spin_lock(&blkg->blkcg->lock); -- cgit v1.1 From 496d5e7560dbb84399dbd92316fc33857aa83900 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Fri, 22 May 2015 17:13:21 -0400 Subject: blkcg: add blkcg_root_css Add global constant blkcg_root_css which points to &blkcg_root.css. This will be used by cgroup writeback support. If blkcg is disabled, it's defined as ERR_PTR(-EINVAL). v2: The declarations moved to include/linux/blk-cgroup.h as suggested by Vivek. Signed-off-by: Tejun Heo Cc: Vivek Goyal Cc: Jens Axboe Signed-off-by: Jens Axboe --- block/blk-cgroup.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'block') diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c index 2a4f77f..54ec172 100644 --- a/block/blk-cgroup.c +++ b/block/blk-cgroup.c @@ -30,6 +30,8 @@ struct blkcg blkcg_root = { .cfq_weight = 2 * CFQ_WEIGHT_DEFAULT, .cfq_leaf_weight = 2 * CFQ_WEIGHT_DEFAULT, }; EXPORT_SYMBOL_GPL(blkcg_root); +struct cgroup_subsys_state * const blkcg_root_css = &blkcg_root.css; + static struct blkcg_policy *blkcg_policy[BLKCG_MAX_POLS]; static bool blkcg_policy_enabled(struct request_queue *q, -- cgit v1.1 From ec438699a9ae0856c2ce20a50dd39cdc7e92a732 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Fri, 22 May 2015 17:13:22 -0400 Subject: cgroup, block: implement task_get_css() and use it in bio_associate_current() bio_associate_current() currently open codes task_css() and css_tryget_online() to find and pin $current's blkcg css. Abstract it into task_get_css() which is implemented from cgroup side. As a task is always associated with an online css for every subsystem except while the css_set update is propagating, task_get_css() retries till css_tryget_online() succeeds. This is a cleanup and shouldn't lead to noticeable behavior changes. Signed-off-by: Tejun Heo Cc: Li Zefan Cc: Jens Axboe Cc: Vivek Goyal Signed-off-by: Jens Axboe --- block/bio.c | 11 +---------- 1 file changed, 1 insertion(+), 10 deletions(-) (limited to 'block') diff --git a/block/bio.c b/block/bio.c index 259197d..c4f8701 100644 --- a/block/bio.c +++ b/block/bio.c @@ -2004,7 +2004,6 @@ EXPORT_SYMBOL(bioset_create_nobvec); int bio_associate_current(struct bio *bio) { struct io_context *ioc; - struct cgroup_subsys_state *css; if (bio->bi_ioc) return -EBUSY; @@ -2013,17 +2012,9 @@ int bio_associate_current(struct bio *bio) if (!ioc) return -ENOENT; - /* acquire active ref on @ioc and associate */ get_io_context_active(ioc); bio->bi_ioc = ioc; - - /* associate blkcg if exists */ - rcu_read_lock(); - css = task_css(current, blkio_cgrp_id); - if (css && css_tryget_online(css)) - bio->bi_css = css; - rcu_read_unlock(); - + bio->bi_css = task_get_css(current, blkio_cgrp_id); return 0; } -- cgit v1.1 From 1d933cf096e3aea15f1aec8297657b7a846fab63 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Fri, 22 May 2015 17:13:24 -0400 Subject: blkcg: implement bio_associate_blkcg() Currently, a bio can only be associated with the io_context and blkcg of %current using bio_associate_current(). This is too restrictive for cgroup writeback support. Implement bio_associate_blkcg() which associates a bio with the specified blkcg. bio_associate_blkcg() leaves the io_context unassociated. bio_associate_current() is updated so that it considers a bio as already associated if it has a blkcg_css, instead of an io_context, associated with it. Signed-off-by: Tejun Heo Cc: Jens Axboe Cc: Vivek Goyal Signed-off-by: Jens Axboe --- block/bio.c | 24 +++++++++++++++++++++++- 1 file changed, 23 insertions(+), 1 deletion(-) (limited to 'block') diff --git a/block/bio.c b/block/bio.c index c4f8701..2a00d34 100644 --- a/block/bio.c +++ b/block/bio.c @@ -1988,6 +1988,28 @@ struct bio_set *bioset_create_nobvec(unsigned int pool_size, unsigned int front_ EXPORT_SYMBOL(bioset_create_nobvec); #ifdef CONFIG_BLK_CGROUP + +/** + * bio_associate_blkcg - associate a bio with the specified blkcg + * @bio: target bio + * @blkcg_css: css of the blkcg to associate + * + * Associate @bio with the blkcg specified by @blkcg_css. Block layer will + * treat @bio as if it were issued by a task which belongs to the blkcg. + * + * This function takes an extra reference of @blkcg_css which will be put + * when @bio is released. The caller must own @bio and is responsible for + * synchronizing calls to this function. + */ +int bio_associate_blkcg(struct bio *bio, struct cgroup_subsys_state *blkcg_css) +{ + if (unlikely(bio->bi_css)) + return -EBUSY; + css_get(blkcg_css); + bio->bi_css = blkcg_css; + return 0; +} + /** * bio_associate_current - associate a bio with %current * @bio: target bio @@ -2005,7 +2027,7 @@ int bio_associate_current(struct bio *bio) { struct io_context *ioc; - if (bio->bi_ioc) + if (bio->bi_css) return -EBUSY; ioc = current->io_context; -- cgit v1.1 From 4452226ea276e74fc3e252c88d9bb7e8f8e44bf0 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Fri, 22 May 2015 17:13:26 -0400 Subject: writeback: move backing_dev_info->state into bdi_writeback Currently, a bdi (backing_dev_info) embeds single wb (bdi_writeback) and the role of the separation is unclear. For cgroup support for writeback IOs, a bdi will be updated to host multiple wb's where each wb serves writeback IOs of a different cgroup on the bdi. To achieve that, a wb should carry all states necessary for servicing writeback IOs for a cgroup independently. This patch moves bdi->state into wb. * enum bdi_state is renamed to wb_state and the prefix of all enums is changed from BDI_ to WB_. * Explicit zeroing of bdi->state is removed without adding zeoring of wb->state as the whole data structure is zeroed on init anyway. * As there's still only one bdi_writeback per backing_dev_info, all uses of bdi->state are mechanically replaced with bdi->wb.state introducing no behavior changes. Signed-off-by: Tejun Heo Reviewed-by: Jan Kara Cc: Jens Axboe Cc: Wu Fengguang Cc: drbd-dev@lists.linbit.com Cc: Neil Brown Cc: Alasdair Kergon Cc: Mike Snitzer Signed-off-by: Jens Axboe --- block/blk-core.c | 1 - 1 file changed, 1 deletion(-) (limited to 'block') diff --git a/block/blk-core.c b/block/blk-core.c index 4afac14d..c3ba9c3 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -621,7 +621,6 @@ struct request_queue *blk_alloc_queue_node(gfp_t gfp_mask, int node_id) q->backing_dev_info.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE; - q->backing_dev_info.state = 0; q->backing_dev_info.capabilities = 0; q->backing_dev_info.name = "block"; q->node = node_id; -- cgit v1.1 From 66114cad64bf76a155fec1f0fff0de771cf909d5 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Fri, 22 May 2015 17:13:32 -0400 Subject: writeback: separate out include/linux/backing-dev-defs.h With the planned cgroup writeback support, backing-dev related declarations will be more widely used across block and cgroup; unfortunately, including backing-dev.h from include/linux/blkdev.h makes cyclic include dependency quite likely. This patch separates out backing-dev-defs.h which only has the essential definitions and updates blkdev.h to include it. c files which need access to more backing-dev details now include backing-dev.h directly. This takes backing-dev.h off the common include dependency chain making it a lot easier to use it across block and cgroup. v2: fs/fat build failure fixed. Signed-off-by: Tejun Heo Reviewed-by: Jan Kara Cc: Jens Axboe Signed-off-by: Jens Axboe --- block/blk-integrity.c | 1 + block/blk-sysfs.c | 1 + block/bounce.c | 1 + block/genhd.c | 1 + 4 files changed, 4 insertions(+) (limited to 'block') diff --git a/block/blk-integrity.c b/block/blk-integrity.c index 79ffb48..f548b64 100644 --- a/block/blk-integrity.c +++ b/block/blk-integrity.c @@ -21,6 +21,7 @@ */ #include +#include #include #include #include diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c index 5677eb7..1b60941 100644 --- a/block/blk-sysfs.c +++ b/block/blk-sysfs.c @@ -6,6 +6,7 @@ #include #include #include +#include #include #include #include diff --git a/block/bounce.c b/block/bounce.c index 4bac725..072280b 100644 --- a/block/bounce.c +++ b/block/bounce.c @@ -13,6 +13,7 @@ #include #include #include +#include #include #include #include diff --git a/block/genhd.c b/block/genhd.c index 0a536dc..d46ba56 100644 --- a/block/genhd.c +++ b/block/genhd.c @@ -8,6 +8,7 @@ #include #include #include +#include #include #include #include -- cgit v1.1 From 89e9b9e07a390c50980d10aa37a04631db5a23ab Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Fri, 22 May 2015 17:13:36 -0400 Subject: writeback: add {CONFIG|BDI_CAP|FS}_CGROUP_WRITEBACK cgroup writeback requires support from both bdi and filesystem sides. Add BDI_CAP_CGROUP_WRITEBACK and FS_CGROUP_WRITEBACK to indicate support and enable BDI_CAP_CGROUP_WRITEBACK on block based bdi's by default. Also, define CONFIG_CGROUP_WRITEBACK which is enabled if both MEMCG and BLK_CGROUP are enabled. inode_cgwb_enabled() which determines whether a given inode's both bdi and fs support cgroup writeback is added. Signed-off-by: Tejun Heo Cc: Jens Axboe Cc: Jan Kara Signed-off-by: Jens Axboe --- block/blk-core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'block') diff --git a/block/blk-core.c b/block/blk-core.c index c3ba9c3..c114a61 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -621,7 +621,7 @@ struct request_queue *blk_alloc_queue_node(gfp_t gfp_mask, int node_id) q->backing_dev_info.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE; - q->backing_dev_info.capabilities = 0; + q->backing_dev_info.capabilities = BDI_CAP_CGROUP_WRITEBACK; q->backing_dev_info.name = "block"; q->node = node_id; -- cgit v1.1 From 52ebea749aaed195245701a8f90a23d672c7a933 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Fri, 22 May 2015 17:13:37 -0400 Subject: writeback: make backing_dev_info host cgroup-specific bdi_writebacks For the planned cgroup writeback support, on each bdi (backing_dev_info), each memcg will be served by a separate wb (bdi_writeback). This patch updates bdi so that a bdi can host multiple wbs (bdi_writebacks). On the default hierarchy, blkcg implicitly enables memcg. This allows using memcg's page ownership for attributing writeback IOs, and every memcg - blkcg combination can be served by its own wb by assigning a dedicated wb to each memcg. This means that there may be multiple wb's of a bdi mapped to the same blkcg. As congested state is per blkcg - bdi combination, those wb's should share the same congested state. This is achieved by tracking congested state via bdi_writeback_congested structs which are keyed by blkcg. bdi->wb remains unchanged and will keep serving the root cgroup. cgwb's (cgroup wb's) for non-root cgroups are created on-demand or looked up while dirtying an inode according to the memcg of the page being dirtied or current task. Each cgwb is indexed on bdi->cgwb_tree by its memcg id. Once an inode is associated with its wb, it can be retrieved using inode_to_wb(). Currently, none of the filesystems has FS_CGROUP_WRITEBACK and all pages will keep being associated with bdi->wb. v3: inode_attach_wb() in account_page_dirtied() moved inside mapping_cap_account_dirty() block where it's known to be !NULL. Also, an unnecessary NULL check before kfree() removed. Both detected by the kbuild bot. v2: Updated so that wb association is per inode and wb is per memcg rather than blkcg. Signed-off-by: Tejun Heo Cc: kbuild test robot Cc: Dan Carpenter Cc: Jens Axboe Cc: Jan Kara Signed-off-by: Jens Axboe --- block/blk-cgroup.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) (limited to 'block') diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c index 54ec172..979cfdb 100644 --- a/block/blk-cgroup.c +++ b/block/blk-cgroup.c @@ -15,6 +15,7 @@ #include #include #include +#include #include #include #include @@ -797,6 +798,8 @@ static void blkcg_css_offline(struct cgroup_subsys_state *css) } spin_unlock_irq(&blkcg->lock); + + wb_blkcg_offline(blkcg); } static void blkcg_css_free(struct cgroup_subsys_state *css) @@ -827,7 +830,9 @@ done: spin_lock_init(&blkcg->lock); INIT_RADIX_TREE(&blkcg->blkg_tree, GFP_ATOMIC); INIT_HLIST_HEAD(&blkcg->blkg_list); - +#ifdef CONFIG_CGROUP_WRITEBACK + INIT_LIST_HEAD(&blkcg->cgwb_list); +#endif return &blkcg->css; } -- cgit v1.1 From ce7acfeaf0363c8b75810908448f61af04d38f91 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Fri, 22 May 2015 17:13:38 -0400 Subject: writeback, blkcg: associate each blkcg_gq with the corresponding bdi_writeback_congested A blkg (blkcg_gq) can be congested and decongested independently from other blkgs on the same request_queue. Accordingly, for cgroup writeback support, the congestion status at bdi (backing_dev_info) should be split and updated separately from matching blkg's. This patch prepares by adding blkg->wb_congested and associating a blkg with its matching per-blkcg bdi_writeback_congested on creation. v2: Updated to associate bdi_writeback_congested instead of bdi_writeback. Signed-off-by: Tejun Heo Cc: Jens Axboe Cc: Jan Kara Cc: Vivek Goyal Signed-off-by: Jens Axboe --- block/blk-cgroup.c | 17 +++++++++++++++-- 1 file changed, 15 insertions(+), 2 deletions(-) (limited to 'block') diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c index 979cfdb..31610ae 100644 --- a/block/blk-cgroup.c +++ b/block/blk-cgroup.c @@ -182,6 +182,7 @@ static struct blkcg_gq *blkg_create(struct blkcg *blkcg, struct blkcg_gq *new_blkg) { struct blkcg_gq *blkg; + struct bdi_writeback_congested *wb_congested; int i, ret; WARN_ON_ONCE(!rcu_read_lock_held()); @@ -193,22 +194,30 @@ static struct blkcg_gq *blkg_create(struct blkcg *blkcg, goto err_free_blkg; } + wb_congested = wb_congested_get_create(&q->backing_dev_info, + blkcg->css.id, GFP_ATOMIC); + if (!wb_congested) { + ret = -ENOMEM; + goto err_put_css; + } + /* allocate */ if (!new_blkg) { new_blkg = blkg_alloc(blkcg, q, GFP_ATOMIC); if (unlikely(!new_blkg)) { ret = -ENOMEM; - goto err_put_css; + goto err_put_congested; } } blkg = new_blkg; + blkg->wb_congested = wb_congested; /* link parent */ if (blkcg_parent(blkcg)) { blkg->parent = __blkg_lookup(blkcg_parent(blkcg), q, false); if (WARN_ON_ONCE(!blkg->parent)) { ret = -EINVAL; - goto err_put_css; + goto err_put_congested; } blkg_get(blkg->parent); } @@ -245,6 +254,8 @@ static struct blkcg_gq *blkg_create(struct blkcg *blkcg, blkg_put(blkg); return ERR_PTR(ret); +err_put_congested: + wb_congested_put(wb_congested); err_put_css: css_put(&blkcg->css); err_free_blkg: @@ -391,6 +402,8 @@ void __blkg_release_rcu(struct rcu_head *rcu_head) if (blkg->parent) blkg_put(blkg->parent); + wb_congested_put(blkg->wb_congested); + blkg_free(blkg); } EXPORT_SYMBOL_GPL(__blkg_release_rcu); -- cgit v1.1 From d40f75a06dd675808eed385d490ba9468200b23f Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Fri, 22 May 2015 17:13:42 -0400 Subject: writeback, blkcg: restructure blk_{set|clear}_queue_congested() blk_{set|clear}_queue_congested() take @q and set or clear, respectively, the congestion state of its bdi's root wb. Because bdi used to be able to handle congestion state only on the root wb, the callers of those functions tested whether the congestion is on the root blkcg and skipped if not. This is cumbersome and makes implementation of per cgroup bdi_writeback congestion state propagation difficult. This patch renames blk_{set|clear}_queue_congested() to blk_{set|clear}_congested(), and makes them take request_list instead of request_queue and test whether the specified request_list is the root one before updating bdi_writeback congestion state. This makes the tests in the callers unnecessary and simplifies them. As there are no external users of these functions, the definitions are moved from include/linux/blkdev.h to block/blk-core.c. This patch doesn't introduce any noticeable behavior difference. Signed-off-by: Tejun Heo Cc: Jens Axboe Cc: Jan Kara Cc: Vivek Goyal Signed-off-by: Jens Axboe --- block/blk-core.c | 62 +++++++++++++++++++++++++++++++++----------------------- 1 file changed, 37 insertions(+), 25 deletions(-) (limited to 'block') diff --git a/block/blk-core.c b/block/blk-core.c index c114a61..f46a43e 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -63,6 +63,28 @@ struct kmem_cache *blk_requestq_cachep; */ static struct workqueue_struct *kblockd_workqueue; +static void blk_clear_congested(struct request_list *rl, int sync) +{ + if (rl != &rl->q->root_rl) + return; +#ifdef CONFIG_CGROUP_WRITEBACK + clear_wb_congested(rl->blkg->wb_congested, sync); +#else + clear_wb_congested(rl->q->backing_dev_info.wb.congested, sync); +#endif +} + +static void blk_set_congested(struct request_list *rl, int sync) +{ + if (rl != &rl->q->root_rl) + return; +#ifdef CONFIG_CGROUP_WRITEBACK + set_wb_congested(rl->blkg->wb_congested, sync); +#else + set_wb_congested(rl->q->backing_dev_info.wb.congested, sync); +#endif +} + void blk_queue_congestion_threshold(struct request_queue *q) { int nr; @@ -842,13 +864,8 @@ static void __freed_request(struct request_list *rl, int sync) { struct request_queue *q = rl->q; - /* - * bdi isn't aware of blkcg yet. As all async IOs end up root - * blkcg anyway, just use root blkcg state. - */ - if (rl == &q->root_rl && - rl->count[sync] < queue_congestion_off_threshold(q)) - blk_clear_queue_congested(q, sync); + if (rl->count[sync] < queue_congestion_off_threshold(q)) + blk_clear_congested(rl, sync); if (rl->count[sync] + 1 <= q->nr_requests) { if (waitqueue_active(&rl->wait[sync])) @@ -881,25 +898,25 @@ static void freed_request(struct request_list *rl, unsigned int flags) int blk_update_nr_requests(struct request_queue *q, unsigned int nr) { struct request_list *rl; + int on_thresh, off_thresh; spin_lock_irq(q->queue_lock); q->nr_requests = nr; blk_queue_congestion_threshold(q); + on_thresh = queue_congestion_on_threshold(q); + off_thresh = queue_congestion_off_threshold(q); - /* congestion isn't cgroup aware and follows root blkcg for now */ - rl = &q->root_rl; - - if (rl->count[BLK_RW_SYNC] >= queue_congestion_on_threshold(q)) - blk_set_queue_congested(q, BLK_RW_SYNC); - else if (rl->count[BLK_RW_SYNC] < queue_congestion_off_threshold(q)) - blk_clear_queue_congested(q, BLK_RW_SYNC); + blk_queue_for_each_rl(rl, q) { + if (rl->count[BLK_RW_SYNC] >= on_thresh) + blk_set_congested(rl, BLK_RW_SYNC); + else if (rl->count[BLK_RW_SYNC] < off_thresh) + blk_clear_congested(rl, BLK_RW_SYNC); - if (rl->count[BLK_RW_ASYNC] >= queue_congestion_on_threshold(q)) - blk_set_queue_congested(q, BLK_RW_ASYNC); - else if (rl->count[BLK_RW_ASYNC] < queue_congestion_off_threshold(q)) - blk_clear_queue_congested(q, BLK_RW_ASYNC); + if (rl->count[BLK_RW_ASYNC] >= on_thresh) + blk_set_congested(rl, BLK_RW_ASYNC); + else if (rl->count[BLK_RW_ASYNC] < off_thresh) + blk_clear_congested(rl, BLK_RW_ASYNC); - blk_queue_for_each_rl(rl, q) { if (rl->count[BLK_RW_SYNC] >= q->nr_requests) { blk_set_rl_full(rl, BLK_RW_SYNC); } else { @@ -1009,12 +1026,7 @@ static struct request *__get_request(struct request_list *rl, int rw_flags, } } } - /* - * bdi isn't aware of blkcg yet. As all async IOs end up - * root blkcg anyway, just use root blkcg state. - */ - if (rl == &q->root_rl) - blk_set_queue_congested(q, is_sync); + blk_set_congested(rl, is_sync); } /* -- cgit v1.1 From 482cf79cdf6669667a914ffd4cbc57a762b55fef Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Fri, 22 May 2015 17:13:43 -0400 Subject: writeback, blkcg: propagate non-root blkcg congestion state Now that bdi layer can handle per-blkcg bdi_writeback_congested state, blk_{set|clear}_congested() can propagate non-root blkcg congestion state to them. This can be easily achieved by disabling the root_rl tests in blk_{set|clear}_congested(). Note that we still need those tests when !CONFIG_CGROUP_WRITEBACK as otherwise we'll end up flipping root blkcg wb's congestion state for events happening on other blkcgs. v2: Updated for bdi_writeback_congested. Signed-off-by: Tejun Heo Cc: Jens Axboe Cc: Jan Kara Cc: Vivek Goyal Signed-off-by: Jens Axboe --- block/blk-core.c | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-) (limited to 'block') diff --git a/block/blk-core.c b/block/blk-core.c index f46a43e..a4a2dbe 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -65,23 +65,26 @@ static struct workqueue_struct *kblockd_workqueue; static void blk_clear_congested(struct request_list *rl, int sync) { - if (rl != &rl->q->root_rl) - return; #ifdef CONFIG_CGROUP_WRITEBACK clear_wb_congested(rl->blkg->wb_congested, sync); #else - clear_wb_congested(rl->q->backing_dev_info.wb.congested, sync); + /* + * If !CGROUP_WRITEBACK, all blkg's map to bdi->wb and we shouldn't + * flip its congestion state for events on other blkcgs. + */ + if (rl == &rl->q->root_rl) + clear_wb_congested(rl->q->backing_dev_info.wb.congested, sync); #endif } static void blk_set_congested(struct request_list *rl, int sync) { - if (rl != &rl->q->root_rl) - return; #ifdef CONFIG_CGROUP_WRITEBACK set_wb_congested(rl->blkg->wb_congested, sync); #else - set_wb_congested(rl->q->backing_dev_info.wb.congested, sync); + /* see blk_clear_congested() */ + if (rl == &rl->q->root_rl) + set_wb_congested(rl->q->backing_dev_info.wb.congested, sync); #endif } -- cgit v1.1