[PATCH -mm v6 1/6] memcg: add page_cgroup_ino helper
From: Vladimir Davydov <hidden>
Date: 2015-06-12 09:53:01
Also in:
cgroups, linux-mm, lkml
Subsystem:
control group - memory resource controller (memcg), memory management, the rest · Maintainers:
Johannes Weiner, Michal Hocko, Roman Gushchin, Shakeel Butt, Andrew Morton, Linus Torvalds
This function returns the inode number of the closest online ancestor of the memory cgroup a page is charged to. It is required for exporting information about which page is charged to which cgroup to userspace, which will be introduced by a following patch. Signed-off-by: Vladimir Davydov <redacted> --- include/linux/memcontrol.h | 1 + mm/memcontrol.c | 23 +++++++++++++++++++++++ 2 files changed, 24 insertions(+)
diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 73b02b0a8f60..50069abebc3c 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h@@ -116,6 +116,7 @@ static inline bool mm_match_cgroup(struct mm_struct *mm, extern struct cgroup_subsys_state *mem_cgroup_css(struct mem_cgroup *memcg); extern struct cgroup_subsys_state *mem_cgroup_css_from_page(struct page *page); +extern unsigned long page_cgroup_ino(struct page *page); struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *, struct mem_cgroup *,
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index acb93c554f6e..894dc2169979 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c@@ -631,6 +631,29 @@ struct cgroup_subsys_state *mem_cgroup_css_from_page(struct page *page) return &memcg->css; } +/** + * page_cgroup_ino - return inode number of the memcg a page is charged to + * @page: the page + * + * Look up the closest online ancestor of the memory cgroup @page is charged to + * and return its inode number or 0 if @page is not charged to any cgroup. It + * is safe to call this function without holding a reference to @page. + */ +unsigned long page_cgroup_ino(struct page *page) +{ + struct mem_cgroup *memcg; + unsigned long ino = 0; + + rcu_read_lock(); + memcg = READ_ONCE(page->mem_cgroup); + while (memcg && !(memcg->css.flags & CSS_ONLINE)) + memcg = parent_mem_cgroup(memcg); + if (memcg) + ino = cgroup_ino(memcg->css.cgroup); + rcu_read_unlock(); + return ino; +} + static struct mem_cgroup_per_zone * mem_cgroup_page_zoneinfo(struct mem_cgroup *memcg, struct page *page) {
--
2.1.4
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