From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: [PATCH 10/49] memcg: implement mem_cgroup_css_from_page() Date: Mon, 6 Apr 2015 15:57:59 -0400 Message-ID: <1428350318-8215-11-git-send-email-tj@kernel.org> References: <1428350318-8215-1-git-send-email-tj@kernel.org> Cc: linux-kernel@vger.kernel.org, jack@suse.cz, hch@infradead.org, hannes@cmpxchg.org, linux-fsdevel@vger.kernel.org, vgoyal@redhat.com, lizefan@huawei.com, cgroups@vger.kernel.org, linux-mm@kvack.org, mhocko@suse.cz, clm@fb.com, fengguang.wu@intel.com, david@fromorbit.com, gthelen@google.com, Tejun Heo To: axboe@kernel.dk Return-path: In-Reply-To: <1428350318-8215-1-git-send-email-tj@kernel.org> Sender: owner-linux-mm@kvack.org List-Id: linux-fsdevel.vger.kernel.org Implement mem_cgroup_css_from_page() which returns the cgroup_subsys_state of the memcg associated with a given page. This will be used by cgroup writeback support. Signed-off-by: Tejun Heo Cc: Johannes Weiner Cc: Michal Hocko --- include/linux/memcontrol.h | 1 + mm/memcontrol.c | 14 ++++++++++++++ 2 files changed, 15 insertions(+) diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index 294498f..637ef62 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -115,6 +115,7 @@ 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); struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *, struct mem_cgroup *, diff --git a/mm/memcontrol.c b/mm/memcontrol.c index fda7025..74241b3 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -591,6 +591,20 @@ struct cgroup_subsys_state *mem_cgroup_css(struct mem_cgroup *memcg) return &memcg->css; } +/** + * mem_cgroup_css_from_page - css of the memcg associated with a page + * @page: page of interest + * + * This function is guaranteed to return a valid cgroup_subsys_state and + * the returned css remains accessible until @page is released. + */ +struct cgroup_subsys_state *mem_cgroup_css_from_page(struct page *page) +{ + if (page->mem_cgroup) + return &page->mem_cgroup->css; + return &root_mem_cgroup->css; +} + static struct mem_cgroup_per_zone * mem_cgroup_page_zoneinfo(struct mem_cgroup *memcg, struct page *page) { -- 2.1.0 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org