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authorSha Zhengju <handai.szj@taobao.com>2013-09-12 15:13:53 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2013-09-12 15:38:02 -0700
commit3ea67d06e4679a16f69f66f43a8d6ee4778985fc (patch)
tree0ec35a312de85ce91bf0bf6e4c5b88440f3d0f1d /mm/memcontrol.c
parent658b72c5a7a033f0dde61b15dff86bf423ce425e (diff)
memcg: add per cgroup writeback pages accounting
Add memcg routines to count writeback pages, later dirty pages will also be accounted. After Kame's commit 89c06bd52fb9 ("memcg: use new logic for page stat accounting"), we can use 'struct page' flag to test page state instead of per page_cgroup flag. But memcg has a feature to move a page from a cgroup to another one and may have race between "move" and "page stat accounting". So in order to avoid the race we have designed a new lock: mem_cgroup_begin_update_page_stat() modify page information -->(a) mem_cgroup_update_page_stat() -->(b) mem_cgroup_end_update_page_stat() It requires both (a) and (b)(writeback pages accounting) to be pretected in mem_cgroup_{begin/end}_update_page_stat(). It's full no-op for !CONFIG_MEMCG, almost no-op if memcg is disabled (but compiled in), rcu read lock in the most cases (no task is moving), and spin_lock_irqsave on top in the slow path. There're two writeback interfaces to modify: test_{clear/set}_page_writeback(). And the lock order is: --> memcg->move_lock --> mapping->tree_lock Signed-off-by: Sha Zhengju <handai.szj@taobao.com> Acked-by: Michal Hocko <mhocko@suse.cz> Reviewed-by: Greg Thelen <gthelen@google.com> Cc: Fengguang Wu <fengguang.wu@intel.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/memcontrol.c')
-rw-r--r--mm/memcontrol.c30
1 files changed, 23 insertions, 7 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 0093bc36c5fc..d5ff3ce13029 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -89,6 +89,7 @@ static const char * const mem_cgroup_stat_names[] = {
"rss",
"rss_huge",
"mapped_file",
+ "writeback",
"swap",
};
@@ -3654,6 +3655,20 @@ void mem_cgroup_split_huge_fixup(struct page *head)
}
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
+static inline
+void mem_cgroup_move_account_page_stat(struct mem_cgroup *from,
+ struct mem_cgroup *to,
+ unsigned int nr_pages,
+ enum mem_cgroup_stat_index idx)
+{
+ /* Update stat data for mem_cgroup */
+ preempt_disable();
+ WARN_ON_ONCE(from->stat->count[idx] < nr_pages);
+ __this_cpu_add(from->stat->count[idx], -nr_pages);
+ __this_cpu_add(to->stat->count[idx], nr_pages);
+ preempt_enable();
+}
+
/**
* mem_cgroup_move_account - move account of the page
* @page: the page
@@ -3699,13 +3714,14 @@ static int mem_cgroup_move_account(struct page *page,
move_lock_mem_cgroup(from, &flags);
- if (!anon && page_mapped(page)) {
- /* Update mapped_file data for mem_cgroup */
- preempt_disable();
- __this_cpu_dec(from->stat->count[MEM_CGROUP_STAT_FILE_MAPPED]);
- __this_cpu_inc(to->stat->count[MEM_CGROUP_STAT_FILE_MAPPED]);
- preempt_enable();
- }
+ if (!anon && page_mapped(page))
+ mem_cgroup_move_account_page_stat(from, to, nr_pages,
+ MEM_CGROUP_STAT_FILE_MAPPED);
+
+ if (PageWriteback(page))
+ mem_cgroup_move_account_page_stat(from, to, nr_pages,
+ MEM_CGROUP_STAT_WRITEBACK);
+
mem_cgroup_charge_statistics(from, page, anon, -nr_pages);
/* caller should have done css_get */