memcg: remove the overhead associated with the root cgroup
Change the memory cgroup to remove the overhead associated with accounting
all pages in the root cgroup. As a side-effect, we can no longer set a
memory hard limit in the root cgroup.
A new flag to track whether the page has been accounted or not has been
added as well. Flags are now set atomically for page_cgroup,
pcg_default_flags is now obsolete and removed.
[akpm@linux-foundation.org: fix a few documentation glitches]
Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/page_cgroup.h b/include/linux/page_cgroup.h
index ada779f..4b938d4 100644
--- a/include/linux/page_cgroup.h
+++ b/include/linux/page_cgroup.h
@@ -38,6 +38,7 @@
PCG_LOCK, /* page cgroup is locked */
PCG_CACHE, /* charged as cache */
PCG_USED, /* this object is in use. */
+ PCG_ACCT_LRU, /* page has been accounted for */
};
#define TESTPCGFLAG(uname, lname) \
@@ -52,11 +53,23 @@
static inline void ClearPageCgroup##uname(struct page_cgroup *pc) \
{ clear_bit(PCG_##lname, &pc->flags); }
+#define TESTCLEARPCGFLAG(uname, lname) \
+static inline int TestClearPageCgroup##uname(struct page_cgroup *pc) \
+ { return test_and_clear_bit(PCG_##lname, &pc->flags); }
+
/* Cache flag is set only once (at allocation) */
TESTPCGFLAG(Cache, CACHE)
+CLEARPCGFLAG(Cache, CACHE)
+SETPCGFLAG(Cache, CACHE)
TESTPCGFLAG(Used, USED)
CLEARPCGFLAG(Used, USED)
+SETPCGFLAG(Used, USED)
+
+SETPCGFLAG(AcctLRU, ACCT_LRU)
+CLEARPCGFLAG(AcctLRU, ACCT_LRU)
+TESTPCGFLAG(AcctLRU, ACCT_LRU)
+TESTCLEARPCGFLAG(AcctLRU, ACCT_LRU)
static inline int page_cgroup_nid(struct page_cgroup *pc)
{