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blkcg: associate a blkg for pages being evicted by swap

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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 <dennisszhou@gmail.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Dennis Zhou (Facebook) 2018-09-11 14:41:31 -04:00 committed by Jens Axboe
parent 5bf9a1f3b4
commit 74b7c02a9b
3 changed files with 68 additions and 28 deletions
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83
block/bio.c
View File

@ -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

11
include/linux/bio.h
View File

@ -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) { }

2
mm/page_io.c
View File

@ -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);