All of lore.kernel.org
 help / color / mirror / Atom feed
From: Johannes Weiner <hannes@cmpxchg.org>
To: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: "linux-mm@kvack.org" <linux-mm@kvack.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"nishimura@mxp.nes.nec.co.jp" <nishimura@mxp.nes.nec.co.jp>,
	"balbir@linux.vnet.ibm.com" <balbir@linux.vnet.ibm.com>
Subject: Re: [BUGFIX][PATCH 2/4] memcg: fix charge path for THP and allow early retirement
Date: Fri, 28 Jan 2011 08:57:24 +0100	[thread overview]
Message-ID: <20110128075724.GB2213@cmpxchg.org> (raw)
In-Reply-To: <20110128122608.cf9be26b.kamezawa.hiroyu@jp.fujitsu.com>

On Fri, Jan 28, 2011 at 12:26:08PM +0900, KAMEZAWA Hiroyuki wrote:
> From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
> 
> When THP is used, Hugepage size charge can happen. It's not handled
> correctly in mem_cgroup_do_charge(). For example, THP can fallback
> to small page allocation when HUGEPAGE allocation seems difficult
> or busy, but memory cgroup doesn't understand it and continue to
> try HUGEPAGE charging. And the worst thing is memory cgroup
> believes 'memory reclaim succeeded' if limit - usage > PAGE_SIZE.
> 
> By this, khugepaged etc...can goes into inifinite reclaim loop
> if tasks in memcg are busy.
> 
> After this patch 
>  - Hugepage allocation will fail if 1st trial of page reclaim fails.
> 
> Changelog:
>  - make changes small. removed renaming codes.
> 
> Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
> ---
>  mm/memcontrol.c |   28 ++++++++++++++++++++++++----
>  1 file changed, 24 insertions(+), 4 deletions(-)

Was there something wrong with my oneline fix?

Really, there is no way to make this a beautiful fix.  The way this
function is split up makes no sense, and the constant addition of more
and more flags just to correctly communicate with _one callsite_
should be an obvious hint.

WARNING: multiple messages have this Message-ID (diff)
From: Johannes Weiner <hannes@cmpxchg.org>
To: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: "linux-mm@kvack.org" <linux-mm@kvack.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"nishimura@mxp.nes.nec.co.jp" <nishimura@mxp.nes.nec.co.jp>,
	"balbir@linux.vnet.ibm.com" <balbir@linux.vnet.ibm.com>
Subject: Re: [BUGFIX][PATCH 2/4] memcg: fix charge path for THP and allow early retirement
Date: Fri, 28 Jan 2011 08:57:24 +0100	[thread overview]
Message-ID: <20110128075724.GB2213@cmpxchg.org> (raw)
In-Reply-To: <20110128122608.cf9be26b.kamezawa.hiroyu@jp.fujitsu.com>

On Fri, Jan 28, 2011 at 12:26:08PM +0900, KAMEZAWA Hiroyuki wrote:
> From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
> 
> When THP is used, Hugepage size charge can happen. It's not handled
> correctly in mem_cgroup_do_charge(). For example, THP can fallback
> to small page allocation when HUGEPAGE allocation seems difficult
> or busy, but memory cgroup doesn't understand it and continue to
> try HUGEPAGE charging. And the worst thing is memory cgroup
> believes 'memory reclaim succeeded' if limit - usage > PAGE_SIZE.
> 
> By this, khugepaged etc...can goes into inifinite reclaim loop
> if tasks in memcg are busy.
> 
> After this patch 
>  - Hugepage allocation will fail if 1st trial of page reclaim fails.
> 
> Changelog:
>  - make changes small. removed renaming codes.
> 
> Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
> ---
>  mm/memcontrol.c |   28 ++++++++++++++++++++++++----
>  1 file changed, 24 insertions(+), 4 deletions(-)

Was there something wrong with my oneline fix?

Really, there is no way to make this a beautiful fix.  The way this
function is split up makes no sense, and the constant addition of more
and more flags just to correctly communicate with _one callsite_
should be an obvious hint.

--
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 policy in Canada: sign http://dissolvethecrtc.ca/
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

  parent reply	other threads:[~2011-01-28  7:57 UTC|newest]

Thread overview: 66+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-01-28  3:22 [BUGFIX][PATCH 0/4] Fixes for memcg with THP KAMEZAWA Hiroyuki
2011-01-28  3:22 ` KAMEZAWA Hiroyuki
2011-01-28  3:24 ` [BUGFIX][PATCH 1/4] memcg: fix limit estimation at reclaim for hugepage KAMEZAWA Hiroyuki
2011-01-28  3:24   ` KAMEZAWA Hiroyuki
2011-01-28  4:40   ` Daisuke Nishimura
2011-01-28  4:40     ` Daisuke Nishimura
2011-01-28  4:49     ` KAMEZAWA Hiroyuki
2011-01-28  4:49       ` KAMEZAWA Hiroyuki
2011-01-28  4:58     ` KAMEZAWA Hiroyuki
2011-01-28  4:58       ` KAMEZAWA Hiroyuki
2011-01-28  5:36       ` Daisuke Nishimura
2011-01-28  5:36         ` Daisuke Nishimura
2011-01-28  8:04       ` Minchan Kim
2011-01-28  8:04         ` Minchan Kim
2011-01-28  8:17         ` Johannes Weiner
2011-01-28  8:17           ` Johannes Weiner
2011-01-28  8:25           ` Minchan Kim
2011-01-28  8:25             ` Minchan Kim
2011-01-28  8:36             ` KAMEZAWA Hiroyuki
2011-01-28  8:36               ` KAMEZAWA Hiroyuki
2011-01-30  2:26               ` Minchan Kim
2011-01-30  2:26                 ` Minchan Kim
2011-01-28  8:41             ` Johannes Weiner
2011-01-28  8:41               ` Johannes Weiner
2011-01-28  8:24         ` KAMEZAWA Hiroyuki
2011-01-28  8:24           ` KAMEZAWA Hiroyuki
2011-01-28  8:37           ` Minchan Kim
2011-01-28  8:37             ` Minchan Kim
2011-01-28  7:52   ` Johannes Weiner
2011-01-28  7:52     ` Johannes Weiner
2011-01-28  8:06     ` KAMEZAWA Hiroyuki
2011-01-28  8:06       ` KAMEZAWA Hiroyuki
2011-01-28  3:26 ` [BUGFIX][PATCH 2/4] memcg: fix charge path for THP and allow early retirement KAMEZAWA Hiroyuki
2011-01-28  3:26   ` KAMEZAWA Hiroyuki
2011-01-28  5:37   ` Daisuke Nishimura
2011-01-28  5:37     ` Daisuke Nishimura
2011-01-28  7:57   ` Johannes Weiner [this message]
2011-01-28  7:57     ` Johannes Weiner
2011-01-28  8:14     ` KAMEZAWA Hiroyuki
2011-01-28  8:14       ` KAMEZAWA Hiroyuki
2011-01-28  9:02       ` Johannes Weiner
2011-01-28  9:02         ` Johannes Weiner
2011-01-28  9:16         ` KAMEZAWA Hiroyuki
2011-01-28  9:16           ` KAMEZAWA Hiroyuki
2011-01-28  3:27 ` [BUGFIX][PATCH 3/4] mecg: fix oom flag at THP charge KAMEZAWA Hiroyuki
2011-01-28  3:27   ` KAMEZAWA Hiroyuki
2011-01-28  5:39   ` Daisuke Nishimura
2011-01-28  5:39     ` Daisuke Nishimura
2011-01-28  5:50     ` KAMEZAWA Hiroyuki
2011-01-28  5:50       ` KAMEZAWA Hiroyuki
2011-01-28  8:02   ` Johannes Weiner
2011-01-28  8:02     ` Johannes Weiner
2011-01-28  8:21     ` KAMEZAWA Hiroyuki
2011-01-28  8:21       ` KAMEZAWA Hiroyuki
2011-01-31  7:41       ` Balbir Singh
2011-01-31  7:41         ` Balbir Singh
2011-01-28  3:28 ` [BUGFIX][PATCH 4/4] memcg: fix khugepaged should skip busy memcg KAMEZAWA Hiroyuki
2011-01-28  3:28   ` KAMEZAWA Hiroyuki
2011-01-28  8:20   ` Daisuke Nishimura
2011-01-28  8:20     ` Daisuke Nishimura
2011-01-28  8:30     ` KAMEZAWA Hiroyuki
2011-01-28  8:30       ` KAMEZAWA Hiroyuki
2011-01-29 12:47 ` [BUGFIX][PATCH 0/4] Fixes for memcg with THP Balbir Singh
2011-01-29 12:47   ` Balbir Singh
2011-01-30 23:55   ` KAMEZAWA Hiroyuki
2011-01-30 23:55     ` KAMEZAWA Hiroyuki

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=20110128075724.GB2213@cmpxchg.org \
    --to=hannes@cmpxchg.org \
    --cc=balbir@linux.vnet.ibm.com \
    --cc=kamezawa.hiroyu@jp.fujitsu.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=nishimura@mxp.nes.nec.co.jp \
    /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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.