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Commit 0d3bd88d authored by Tejun Heo's avatar Tejun Heo Committed by Jens Axboe
Browse files

swap,blkcg: issue swap io with the appropriate context 



For backcharging we need to know who the page belongs to when swapping
it out.  We don't worry about things that do ->rw_page (zram etc) at the
moment, we're only worried about pages that actually go to a block
device.

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Signed-off-by: default avatarJosef Bacik <jbacik@fb.com>
Acked-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
Acked-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 0d1e0c7c

block/bio.c

+24 −0
Original line number Diff line number Diff line
@@ -2015,6 +2015,30 @@ 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

include/linux/bio.h

+7 −0
Original line number Diff line number Diff line
@@ -553,6 +553,13 @@ do { \ 
#define bio_dev(bio) \

	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);

#else

static inline int bio_associate_blkcg_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);

mm/page_io.c

+1 −0
Original line number Diff line number Diff line
@@ -339,6 +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);

	count_swpout_vm_event(page);

	set_page_writeback(page);

	unlock_page(page);