From: Johannes Weiner <hannes@cmpxchg.org>
To: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Michal Hocko <mhocko@suse.cz>,
Balbir Singh <bsingharora@gmail.com>,
cgroups@vger.kernel.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org
Subject: Re: [patch 8/8] mm: memcg: modify PageCgroupCache non-atomically
Date: Thu, 24 Nov 2011 10:13:12 +0100 [thread overview]
Message-ID: <20111124091312.GE6843@cmpxchg.org> (raw)
In-Reply-To: <20111124091328.d28d9f55.kamezawa.hiroyu@jp.fujitsu.com>
On Thu, Nov 24, 2011 at 09:13:28AM +0900, KAMEZAWA Hiroyuki wrote:
> On Wed, 23 Nov 2011 16:42:31 +0100
> Johannes Weiner <hannes@cmpxchg.org> wrote:
>
> > From: Johannes Weiner <jweiner@redhat.com>
> >
> > This bit is protected by lock_page_cgroup(), there is no need for
> > locked operations when setting and clearing it.
> >
> > Signed-off-by: Johannes Weiner <jweiner@redhat.com>
>
> Hm. non-atomic ops for pc->flags seems dangerous.
> How about try to remove PCG_CACHE ? Maybe we can depends on PageAnon(page).
> We see 'page' on memcg->lru now.
> I'm sorry I forgot why we needed PCG_CACHE flag..
The problem is that we charge/uncharged pages that are not fully
rmapped and so PageAnon() is not reliable. I forgot if there are more
places, but the commit_charge in migration was a prominent one.
I have a patch set that reworks migration so to only commit pages that
are fully rmapped but it clashed with the THP patches and I didn't see
too much value to fix it up. But I should probably revive it, because
it makes some things simpler.
As I replied to Hugh, it might even work for PCG_CACHE, but it's
definitely dangerous and not worth the complex dependencies it brings
on other parts of the code, so please consider 7/8 and 8/8 dropped.
--
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>
next prev parent reply other threads:[~2011-11-24 9:13 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-11-23 15:42 [patch 0/8] mm: memcg fixlets for 3.3 Johannes Weiner
2011-11-23 15:42 ` [patch 1/8] mm: oom_kill: remove memcg argument from oom_kill_task() Johannes Weiner
2011-11-23 22:35 ` David Rientjes
2011-11-23 23:57 ` KAMEZAWA Hiroyuki
2011-11-24 9:07 ` Michal Hocko
2011-11-28 0:37 ` Balbir Singh
2011-11-23 15:42 ` [patch 2/8] mm: unify remaining mem_cont, mem, etc. variable names to memcg Johannes Weiner
2011-11-23 22:40 ` David Rientjes
2011-11-23 23:58 ` KAMEZAWA Hiroyuki
2011-11-24 9:17 ` Michal Hocko
2011-11-28 0:42 ` Balbir Singh
2011-11-23 15:42 ` [patch 3/8] mm: memcg: clean up fault accounting Johannes Weiner
2011-11-24 0:00 ` KAMEZAWA Hiroyuki
2011-11-24 9:33 ` Michal Hocko
2011-11-24 9:51 ` Johannes Weiner
2011-11-28 0:45 ` Balbir Singh
2011-11-23 15:42 ` [patch 4/8] mm: memcg: lookup_page_cgroup (almost) never returns NULL Johannes Weiner
2011-11-24 0:01 ` KAMEZAWA Hiroyuki
2011-11-24 9:52 ` Michal Hocko
2011-11-24 10:05 ` Johannes Weiner
2011-11-24 10:26 ` Michal Hocko
2011-11-28 9:15 ` Johannes Weiner
2011-11-28 9:34 ` Johannes Weiner
2011-11-28 10:12 ` Michal Hocko
2011-11-28 7:03 ` Balbir Singh
2011-11-28 9:17 ` Johannes Weiner
2011-11-23 15:42 ` [patch 5/8] mm: memcg: remove unneeded checks from newpage_charge() Johannes Weiner
2011-11-24 0:04 ` KAMEZAWA Hiroyuki
2011-11-24 9:04 ` Johannes Weiner
2011-11-24 10:30 ` Michal Hocko
2011-11-24 11:58 ` Johannes Weiner
2011-11-23 15:42 ` [patch 6/8] mm: memcg: remove unneeded checks from uncharge_page() Johannes Weiner
2011-11-24 0:06 ` KAMEZAWA Hiroyuki
2011-11-24 9:06 ` Johannes Weiner
2011-11-24 10:34 ` Michal Hocko
2011-11-23 15:42 ` [patch 7/8] mm: memcg: modify PageCgroupAcctLRU non-atomically Johannes Weiner
2011-11-23 18:52 ` Hugh Dickins
2011-11-24 8:53 ` Johannes Weiner
2011-11-24 0:09 ` KAMEZAWA Hiroyuki
2011-11-24 8:55 ` Johannes Weiner
2011-11-23 15:42 ` [patch 8/8] mm: memcg: modify PageCgroupCache non-atomically Johannes Weiner
2011-11-24 0:13 ` KAMEZAWA Hiroyuki
2011-11-24 9:13 ` Johannes Weiner [this message]
2011-11-24 6:09 ` [patch 0/8] mm: memcg fixlets for 3.3 Balbir Singh
2011-11-24 9:45 ` Johannes Weiner
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20111124091312.GE6843@cmpxchg.org \
--to=hannes@cmpxchg.org \
--cc=akpm@linux-foundation.org \
--cc=bsingharora@gmail.com \
--cc=cgroups@vger.kernel.org \
--cc=kamezawa.hiroyu@jp.fujitsu.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mhocko@suse.cz \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox