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Commit 74b7c02a authored by Dennis Zhou (Facebook)'s avatar Dennis Zhou (Facebook) Committed by Jens Axboe
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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: default avatarDennis Zhou <dennisszhou@gmail.com>
Reviewed-by: default avatarJosef Bacik <josef@toxicpanda.com>
Acked-by: default avatarTejun Heo <tj@kernel.org>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 5bf9a1f3

block/bio.c

+59 −24
Original line number Diff line number Diff line
@@ -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

include/linux/bio.h

+8 −3
Original line number Diff line number Diff line
@@ -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,

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) { }

mm/page_io.c

+1 −1
Original line number Diff line number Diff line
@@ -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);