From 74b7c02a9bc124ee3df0d77880ee26db0a325516 Mon Sep 17 00:00:00 2001 From: "Dennis Zhou (Facebook)" Date: Tue, 11 Sep 2018 14:41:31 -0400 Subject: [PATCH] blkcg: associate a blkg for pages being evicted by swap A prior patch in this series added blkg association to bios issued by cgroups. There are two other paths that we want to attribute work back to the appropriate cgroup: swap and writeback. Here we modify the way swap tags bios to include the blkg. Writeback will be tackle in the next patch. Signed-off-by: Dennis Zhou Reviewed-by: Josef Bacik Acked-by: Tejun Heo Signed-off-by: Jens Axboe --- block/bio.c | 83 ++++++++++++++++++++++++++++++++------------- include/linux/bio.h | 11 ++++-- mm/page_io.c | 2 +- 3 files changed, 68 insertions(+), 28 deletions(-) diff --git a/block/bio.c b/block/bio.c index 80c948da061c..387480de6992 100644 --- a/block/bio.c +++ b/block/bio.c @@ -1956,30 +1956,6 @@ EXPORT_SYMBOL(bioset_init_from_src); #ifdef CONFIG_BLK_CGROUP -#ifdef CONFIG_MEMCG -/** - * bio_associate_blkcg_from_page - associate a bio with the page's blkcg - * @bio: target bio - * @page: the page to lookup the blkcg from - * - * Associate @bio with the blkcg from @page's owning memcg. This works like - * every other associate function wrt references. - */ -int bio_associate_blkcg_from_page(struct bio *bio, struct page *page) -{ - struct cgroup_subsys_state *blkcg_css; - - if (unlikely(bio->bi_css)) - return -EBUSY; - if (!page->mem_cgroup) - return 0; - blkcg_css = cgroup_get_e_css(page->mem_cgroup->css.cgroup, - &io_cgrp_subsys); - bio->bi_css = blkcg_css; - return 0; -} -#endif /* CONFIG_MEMCG */ - /** * bio_associate_blkcg - associate a bio with the specified blkcg * @bio: target bio @@ -2030,6 +2006,65 @@ int bio_associate_blkg(struct bio *bio, struct blkcg_gq *blkg) return 0; } +static int __bio_associate_blkg_from_css(struct bio *bio, + struct cgroup_subsys_state *css) +{ + struct blkcg_gq *blkg; + + rcu_read_lock(); + + blkg = blkg_lookup_create(css_to_blkcg(css), bio->bi_disk->queue); + + rcu_read_unlock(); + + return bio_associate_blkg(bio, blkg); +} + +/** + * bio_associate_blkg_from_css - associate a bio with a specified css + * @bio: target bio + * @css: target css + * + * Associate @bio with the blkg found by combining the css's blkg and the + * request_queue of the @bio. This takes a reference on the css that will + * be put upon freeing of @bio. + */ +int bio_associate_blkg_from_css(struct bio *bio, + struct cgroup_subsys_state *css) +{ + css_get(css); + bio->bi_css = css; + return __bio_associate_blkg_from_css(bio, css); +} +EXPORT_SYMBOL_GPL(bio_associate_blkg_from_css); + +#ifdef CONFIG_MEMCG +/** + * bio_associate_blkg_from_page - associate a bio with the page's blkg + * @bio: target bio + * @page: the page to lookup the blkcg from + * + * Associate @bio with the blkg from @page's owning memcg and the respective + * request_queue. This works like every other associate function wrt + * references. + * + * Note: this must be called after bio has an associated device. + */ +int bio_associate_blkg_from_page(struct bio *bio, struct page *page) +{ + struct cgroup_subsys_state *css; + + if (unlikely(bio->bi_css)) + return -EBUSY; + if (!page->mem_cgroup) + return 0; + css = cgroup_get_e_css(page->mem_cgroup->css.cgroup, &io_cgrp_subsys); + bio->bi_css = css; + + return __bio_associate_blkg_from_css(bio, css); +} +#endif /* CONFIG_MEMCG */ + /** * bio_associate_create_blkg - associate a bio with a blkg from q * @q: request_queue where bio is going diff --git a/include/linux/bio.h b/include/linux/bio.h index 829cd0bb407d..c73a870ebc0e 100644 --- a/include/linux/bio.h +++ b/include/linux/bio.h @@ -533,21 +533,26 @@ do { \ disk_devt((bio)->bi_disk) #if defined(CONFIG_MEMCG) && defined(CONFIG_BLK_CGROUP) -int bio_associate_blkcg_from_page(struct bio *bio, struct page *page); +int bio_associate_blkg_from_page(struct bio *bio, struct page *page); #else -static inline int bio_associate_blkcg_from_page(struct bio *bio, - struct page *page) { return 0; } +static inline int bio_associate_blkg_from_page(struct bio *bio, + struct page *page) { return 0; } #endif #ifdef CONFIG_BLK_CGROUP int bio_associate_blkcg(struct bio *bio, struct cgroup_subsys_state *blkcg_css); int bio_associate_blkg(struct bio *bio, struct blkcg_gq *blkg); +int bio_associate_blkg_from_css(struct bio *bio, + struct cgroup_subsys_state *css); int bio_associate_create_blkg(struct request_queue *q, struct bio *bio); void bio_disassociate_task(struct bio *bio); void bio_clone_blkcg_association(struct bio *dst, struct bio *src); #else /* CONFIG_BLK_CGROUP */ static inline int bio_associate_blkcg(struct bio *bio, struct cgroup_subsys_state *blkcg_css) { return 0; } +static inline int bio_associate_blkg_from_css(struct bio *bio, + struct cgroup_subsys_state *css) +{ return 0; } static inline int bio_associate_create_blkg(struct request_queue *q, struct bio *bio) { return 0; } static inline void bio_disassociate_task(struct bio *bio) { } diff --git a/mm/page_io.c b/mm/page_io.c index aafd19ec1db4..573d3663d846 100644 --- a/mm/page_io.c +++ b/mm/page_io.c @@ -339,7 +339,7 @@ int __swap_writepage(struct page *page, struct writeback_control *wbc, goto out; } bio->bi_opf = REQ_OP_WRITE | REQ_SWAP | wbc_to_write_flags(wbc); - bio_associate_blkcg_from_page(bio, page); + bio_associate_blkg_from_page(bio, page); count_swpout_vm_event(page); set_page_writeback(page); unlock_page(page);