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authorTejun Heo <tj@kernel.org>2018-07-03 11:14:54 -0400
committerJens Axboe <axboe@kernel.dk>2018-07-09 09:07:54 -0600
commit0d3bd88d54f513723602b361dccfc71639f50779 (patch)
tree349c7095f6e4faad0eadd64b516e80e1a0d3ef8d /block
parent0d1e0c7cd5909d6c6aa0957179318e13fcca971a (diff)
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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: Tejun Heo <tj@kernel.org> Signed-off-by: Josef Bacik <jbacik@fb.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block')
-rw-r--r--block/bio.c24
1 files changed, 24 insertions, 0 deletions
diff --git a/block/bio.c b/block/bio.c
index 044571538574..5f84f5c3887b 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -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