[PATCH 08/14] blkcg: associate a blkg for pages being evicted by swap
From: Dennis Zhou <dennis@kernel.org>
Date: 2018-12-05 17:11:45
Also in:
cgroups, lkml
Subsystem:
block layer, memory management, memory management - swap, the rest · Maintainers:
Jens Axboe, Andrew Morton, Chris Li, Kairui Song, Linus Torvalds
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 <dennis@kernel.org> Reviewed-by: Josef Bacik <josef@toxicpanda.com> Acked-by: Tejun Heo <tj@kernel.org> --- block/bio.c | 62 +++++++++++++++++++++++++++------------------ include/linux/bio.h | 6 ++--- mm/page_io.c | 2 +- 3 files changed, 42 insertions(+), 28 deletions(-)
diff --git a/block/bio.c b/block/bio.c
index 90089124b512..f0f069c1823c 100644
--- a/block/bio.c
+++ b/block/bio.c@@ -1957,30 +1957,6 @@ 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
@@ -2045,6 +2021,44 @@ static void __bio_associate_blkg(struct bio *bio, struct blkcg_gq *blkg) bio->bi_blkg = blkg_try_get_closest(blkg); } +static void __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); + __bio_associate_blkg(bio, blkg); + + rcu_read_unlock(); +} + +#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. + */ +void bio_associate_blkg_from_page(struct bio *bio, struct page *page) +{ + struct cgroup_subsys_state *css; + + if (unlikely(bio->bi_css)) + return; + if (!page->mem_cgroup) + return; + + css = cgroup_get_e_css(page->mem_cgroup->css.cgroup, &io_cgrp_subsys); + bio->bi_css = css; + __bio_associate_blkg_from_css(bio, css); +} +#endif /* CONFIG_MEMCG */ + /** * bio_associate_blkg - associate a bio with a blkg * @bio: target bio
diff --git a/include/linux/bio.h b/include/linux/bio.h
index 6ee2ea8b378a..f13572c254a7 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h@@ -505,10 +505,10 @@ 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); +void 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 void bio_associate_blkg_from_page(struct bio *bio, + struct page *page) { } #endif #ifdef CONFIG_BLK_CGROUP
diff --git a/mm/page_io.c b/mm/page_io.c
index 5bdfd21c1bd9..3475733b1926 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);
--
2.17.1