From 1ed8d48c57bf7400eac7b8dc622ab0413715cafb Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Tue, 18 Aug 2015 14:54:52 -0700 Subject: writeback: bdi_for_each_wb() iteration is memcg ID based not blkcg wb's (bdi_writeback's) are currently keyed by memcg ID; however, in an earlier implementation, wb's were keyed by blkcg ID. bdi_for_each_wb() walks bdi->cgwb_tree in the ascending ID order and allows iterations to start from an arbitrary ID which is used to interrupt and resume iterations. Unfortunately, while changing wb to be keyed by memcg ID instead of blkcg, bdi_for_each_wb() was missed and is still assuming that wb's are keyed by blkcg ID. This doesn't affect iterations which don't get interrupted but bdi_split_work_to_wbs() makes use of iteration resuming on allocation failures and thus may incorrectly skip or repeat wb's. Fix it by changing bdi_for_each_wb() to take memcg IDs instead of blkcg IDs and updating bdi_split_work_to_wbs() accordingly. Signed-off-by: Tejun Heo Signed-off-by: Jens Axboe --- include/linux/backing-dev.h | 24 ++++++++++++------------ 1 file changed, 12 insertions(+), 12 deletions(-) (limited to 'include/linux/backing-dev.h') diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h index 0fe9df983ab7..23ebb946e66f 100644 --- a/include/linux/backing-dev.h +++ b/include/linux/backing-dev.h @@ -402,7 +402,7 @@ static inline void unlocked_inode_to_wb_end(struct inode *inode, bool locked) } struct wb_iter { - int start_blkcg_id; + int start_memcg_id; struct radix_tree_iter tree_iter; void **slot; }; @@ -414,9 +414,9 @@ static inline struct bdi_writeback *__wb_iter_next(struct wb_iter *iter, WARN_ON_ONCE(!rcu_read_lock_held()); - if (iter->start_blkcg_id >= 0) { - iter->slot = radix_tree_iter_init(titer, iter->start_blkcg_id); - iter->start_blkcg_id = -1; + if (iter->start_memcg_id >= 0) { + iter->slot = radix_tree_iter_init(titer, iter->start_memcg_id); + iter->start_memcg_id = -1; } else { iter->slot = radix_tree_next_slot(iter->slot, titer, 0); } @@ -430,30 +430,30 @@ static inline struct bdi_writeback *__wb_iter_next(struct wb_iter *iter, static inline struct bdi_writeback *__wb_iter_init(struct wb_iter *iter, struct backing_dev_info *bdi, - int start_blkcg_id) + int start_memcg_id) { - iter->start_blkcg_id = start_blkcg_id; + iter->start_memcg_id = start_memcg_id; - if (start_blkcg_id) + if (start_memcg_id) return __wb_iter_next(iter, bdi); else return &bdi->wb; } /** - * bdi_for_each_wb - walk all wb's of a bdi in ascending blkcg ID order + * bdi_for_each_wb - walk all wb's of a bdi in ascending memcg ID order * @wb_cur: cursor struct bdi_writeback pointer * @bdi: bdi to walk wb's of * @iter: pointer to struct wb_iter to be used as iteration buffer - * @start_blkcg_id: blkcg ID to start iteration from + * @start_memcg_id: memcg ID to start iteration from * * Iterate @wb_cur through the wb's (bdi_writeback's) of @bdi in ascending - * blkcg ID order starting from @start_blkcg_id. @iter is struct wb_iter + * memcg ID order starting from @start_memcg_id. @iter is struct wb_iter * to be used as temp storage during iteration. rcu_read_lock() must be * held throughout iteration. */ -#define bdi_for_each_wb(wb_cur, bdi, iter, start_blkcg_id) \ - for ((wb_cur) = __wb_iter_init(iter, bdi, start_blkcg_id); \ +#define bdi_for_each_wb(wb_cur, bdi, iter, start_memcg_id) \ + for ((wb_cur) = __wb_iter_init(iter, bdi, start_memcg_id); \ (wb_cur); (wb_cur) = __wb_iter_next(iter, bdi)) #else /* CONFIG_CGROUP_WRITEBACK */ -- cgit v1.2.3-70-g09d2 From c165b3e3c7bb68c2ed55a5ac2623f030d01d9567 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Tue, 18 Aug 2015 14:55:29 -0700 Subject: blkcg: rename subsystem name from blkio to io blkio interface has become messy over time and is currently the largest. In addition to the inconsistent naming scheme, it has multiple stat files which report more or less the same thing, a number of debug stat files which expose internal details which shouldn't have been part of the public interface in the first place, recursive and non-recursive stats and leaf and non-leaf knobs. Both recursive vs. non-recursive and leaf vs. non-leaf distinctions don't make any sense on the unified hierarchy as only leaf cgroups can contain processes. cgroups is going through a major interface revision with the unified hierarchy involving significant fundamental usage changes and given that a significant portion of the interface doesn't make sense anymore, it's a good time to reorganize the interface. As the first step, this patch renames the external visible subsystem name from "blkio" to "io". This is more concise, matches the other two major subsystem names, "cpu" and "memory", and better suited as blkcg will be involved in anything writeback related too whether an actual block device is involved or not. As the subsystem legacy_name is set to "blkio", the only userland visible change outside the unified hierarchy is that blkcg is reported as "io" instead of "blkio" in the subsystem initialized message during boot. On the unified hierarchy, blkcg now appears as "io". Signed-off-by: Tejun Heo Cc: Li Zefan Cc: Johannes Weiner Cc: cgroups@vger.kernel.org Signed-off-by: Jens Axboe --- block/bio.c | 2 +- block/blk-cgroup.c | 7 ++++--- include/linux/backing-dev.h | 2 +- include/linux/blk-cgroup.h | 4 ++-- include/linux/cgroup_subsys.h | 2 +- mm/backing-dev.c | 4 ++-- 6 files changed, 11 insertions(+), 10 deletions(-) (limited to 'include/linux/backing-dev.h') diff --git a/block/bio.c b/block/bio.c index d6e5ba3399f0..c52222c6c69b 100644 --- a/block/bio.c +++ b/block/bio.c @@ -2046,7 +2046,7 @@ int bio_associate_current(struct bio *bio) get_io_context_active(ioc); bio->bi_ioc = ioc; - bio->bi_css = task_get_css(current, blkio_cgrp_id); + bio->bi_css = task_get_css(current, io_cgrp_id); return 0; } EXPORT_SYMBOL_GPL(bio_associate_current); diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c index 0af3bff198ed..fc197ea4c992 100644 --- a/block/blk-cgroup.c +++ b/block/blk-cgroup.c @@ -1089,12 +1089,13 @@ static int blkcg_can_attach(struct cgroup_subsys_state *css, return ret; } -struct cgroup_subsys blkio_cgrp_subsys = { +struct cgroup_subsys io_cgrp_subsys = { .css_alloc = blkcg_css_alloc, .css_offline = blkcg_css_offline, .css_free = blkcg_css_free, .can_attach = blkcg_can_attach, .legacy_cftypes = blkcg_files, + .legacy_name = "blkio", #ifdef CONFIG_MEMCG /* * This ensures that, if available, memcg is automatically enabled @@ -1104,7 +1105,7 @@ struct cgroup_subsys blkio_cgrp_subsys = { .depends_on = 1 << memory_cgrp_id, #endif }; -EXPORT_SYMBOL_GPL(blkio_cgrp_subsys); +EXPORT_SYMBOL_GPL(io_cgrp_subsys); /** * blkcg_activate_policy - activate a blkcg policy on a request_queue @@ -1266,7 +1267,7 @@ int blkcg_policy_register(struct blkcg_policy *pol) /* everything is in place, add intf files for the new policy */ if (pol->cftypes) - WARN_ON(cgroup_add_legacy_cftypes(&blkio_cgrp_subsys, + WARN_ON(cgroup_add_legacy_cftypes(&io_cgrp_subsys, pol->cftypes)); mutex_unlock(&blkcg_pol_register_mutex); return 0; diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h index 23ebb946e66f..5a5d79ee256f 100644 --- a/include/linux/backing-dev.h +++ b/include/linux/backing-dev.h @@ -286,7 +286,7 @@ static inline struct bdi_writeback *wb_find_current(struct backing_dev_info *bdi * %current's blkcg equals the effective blkcg of its memcg. No * need to use the relatively expensive cgroup_get_e_css(). */ - if (likely(wb && wb->blkcg_css == task_css(current, blkio_cgrp_id))) + if (likely(wb && wb->blkcg_css == task_css(current, io_cgrp_id))) return wb; return NULL; } diff --git a/include/linux/blk-cgroup.h b/include/linux/blk-cgroup.h index 286e1bde249f..db89acd2a864 100644 --- a/include/linux/blk-cgroup.h +++ b/include/linux/blk-cgroup.h @@ -221,7 +221,7 @@ static inline struct blkcg *css_to_blkcg(struct cgroup_subsys_state *css) static inline struct blkcg *task_blkcg(struct task_struct *tsk) { - return css_to_blkcg(task_css(tsk, blkio_cgrp_id)); + return css_to_blkcg(task_css(tsk, io_cgrp_id)); } static inline struct blkcg *bio_blkcg(struct bio *bio) @@ -234,7 +234,7 @@ static inline struct blkcg *bio_blkcg(struct bio *bio) static inline struct cgroup_subsys_state * task_get_blkcg_css(struct task_struct *task) { - return task_get_css(task, blkio_cgrp_id); + return task_get_css(task, io_cgrp_id); } /** diff --git a/include/linux/cgroup_subsys.h b/include/linux/cgroup_subsys.h index e4a96fb14403..86b5056104df 100644 --- a/include/linux/cgroup_subsys.h +++ b/include/linux/cgroup_subsys.h @@ -16,7 +16,7 @@ SUBSYS(cpuacct) #endif #if IS_ENABLED(CONFIG_BLK_CGROUP) -SUBSYS(blkio) +SUBSYS(io) #endif #if IS_ENABLED(CONFIG_MEMCG) diff --git a/mm/backing-dev.c b/mm/backing-dev.c index dac5bf59309d..d0ee90e72867 100644 --- a/mm/backing-dev.c +++ b/mm/backing-dev.c @@ -523,7 +523,7 @@ static int cgwb_create(struct backing_dev_info *bdi, int ret = 0; memcg = mem_cgroup_from_css(memcg_css); - blkcg_css = cgroup_get_e_css(memcg_css->cgroup, &blkio_cgrp_subsys); + blkcg_css = cgroup_get_e_css(memcg_css->cgroup, &io_cgrp_subsys); blkcg = css_to_blkcg(blkcg_css); memcg_cgwb_list = mem_cgroup_cgwb_list(memcg); blkcg_cgwb_list = &blkcg->cgwb_list; @@ -645,7 +645,7 @@ struct bdi_writeback *wb_get_create(struct backing_dev_info *bdi, /* see whether the blkcg association has changed */ blkcg_css = cgroup_get_e_css(memcg_css->cgroup, - &blkio_cgrp_subsys); + &io_cgrp_subsys); if (unlikely(wb->blkcg_css != blkcg_css || !wb_tryget(wb))) wb = NULL; -- cgit v1.2.3-70-g09d2