Re: [PATCH] memcg: remove unnecessary thp check at page stat accounting
From: Michal Hocko <hidden>
Date: 2012-01-19 09:34:16
Also in:
lkml
On Thu 19-01-12 16:14:45, KAMEZAWA Hiroyuki wrote:
Thank you very much for reviewing previous RFC series.
This is a patch against memcg-devel and linux-next (can by applied without HUNKs).
==
From 64641b360839b029bb353fbd95f7554cc806ed05 Mon Sep 17 00:00:00 2001
From: KAMEZAWA Hiroyuki <redacted>
Date: Thu, 12 Jan 2012 16:08:33 +0900
Subject: [PATCH] memcg: remove unnecessary thp check in mem_cgroup_update_page_stat()
commit 58b318ecf(memcg-devel)
memcg: make mem_cgroup_split_huge_fixup() more efficient
removes move_lock_page_cgroup() in thp-split path.I wouldn't refer to something which will change its commit id by its SHA. I guess the subject is sufficient. Btw. do we really need to mention this? Is it just to make sure that this doesn't get merged withtout the mentioned patch?
So, We do not have to check PageTransHuge in mem_cgroup_update_page_stat and fallback into the locked accounting because both move charge and thp split up are done with compound_lock so they cannot race. update vs. move is protected by the mem_cgroup_stealed sufficiently. PageTransHuge pages shouldn't appear in this code path currently because we are tracking only file pages at the moment but later we are planning to track also other pages (e.g. mlocked ones). Signed-off-by: KAMEZAWA Hiroyuki <redacted>
Other than that Acked-by: Michal Hocko <redacted>
quoted hunk ↗ jump to hunk
--- mm/memcontrol.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-)diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 5073474..fb2dfc3 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c@@ -1801,7 +1801,7 @@ void mem_cgroup_update_page_stat(struct page *page, if (unlikely(!memcg || !PageCgroupUsed(pc))) goto out; /* pc->mem_cgroup is unstable ? */ - if (unlikely(mem_cgroup_stealed(memcg)) || PageTransHuge(page)) { + if (unlikely(mem_cgroup_stealed(memcg))) { /* take a lock against to access pc->mem_cgroup */ move_lock_page_cgroup(pc, &flags); need_unlock = true;-- 1.7.4.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
-- Michal Hocko SUSE Labs SUSE LINUX s.r.o. Lihovarska 1060/12 190 00 Praha 9 Czech Republic -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>