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From: Johannes Weiner <jweiner@redhat.com>
To: Michal Hocko <mhocko@suse.cz>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
	Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>,
	Balbir Singh <bsingharora@gmail.com>,
	Ying Han <yinghan@google.com>, Greg Thelen <gthelen@google.com>,
	Michel Lespinasse <walken@google.com>,
	Rik van Riel <riel@redhat.com>,
	Minchan Kim <minchan.kim@gmail.com>,
	Christoph Hellwig <hch@infradead.org>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [patch 08/11] mm: vmscan: convert global reclaim to per-memcg LRU lists
Date: Wed, 21 Sep 2011 15:51:43 +0200	[thread overview]
Message-ID: <20110921135142.GE22516@redhat.com> (raw)
In-Reply-To: <20110921131045.GD8501@tiehlicka.suse.cz>

On Wed, Sep 21, 2011 at 03:10:45PM +0200, Michal Hocko wrote:
> On Mon 12-09-11 12:57:25, Johannes Weiner wrote:
> > The global per-zone LRU lists are about to go away on memcg-enabled
> > kernels, global reclaim must be able to find its pages on the
> > per-memcg LRU lists.
> > 
> > Since the LRU pages of a zone are distributed over all existing memory
> > cgroups, a scan target for a zone is complete when all memory cgroups
> > are scanned for their proportional share of a zone's memory.
> > 
> > The forced scanning of small scan targets from kswapd is limited to
> > zones marked unreclaimable, otherwise kswapd can quickly overreclaim
> > by force-scanning the LRU lists of multiple memory cgroups.
> > 
> > Signed-off-by: Johannes Weiner <jweiner@redhat.com>
> 
> Reviewed-by: Michal Hocko <mhocko@suse.cz>

Thanks

> Minor nit bellow

> > @@ -2451,13 +2445,24 @@ unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *mem_cont,
> >  static void age_active_anon(struct zone *zone, struct scan_control *sc,
> >  			    int priority)
> >  {
> > -	struct mem_cgroup_zone mz = {
> > -		.mem_cgroup = NULL,
> > -		.zone = zone,
> > -	};
> > +	struct mem_cgroup *mem;
> > +
> > +	if (!total_swap_pages)
> > +		return;
> > +
> > +	mem = mem_cgroup_iter(NULL, NULL, NULL);
> 
> Wouldn't be for_each_mem_cgroup more appropriate? Macro is not exported
> but probably worth exporting? The same applies for
> scan_zone_unevictable_pages from the previous patch.

Unfortunately, in generic code, these loops need to be layed out like
this for !CONFIG_MEMCG to do the right thing.  mem_cgroup_iter() will
return NULL and the loop has to execute exactly once.

This is something that will go away once we implement Christoph's
suggestion of always having a (skeleton) root_mem_cgroup around, even
for !CONFIG_MEMCG.

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  reply	other threads:[~2011-09-21 13:51 UTC|newest]

Thread overview: 65+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-09-12 10:57 [patch 0/11] mm: memcg naturalization -rc3 Johannes Weiner
2011-09-12 10:57 ` [patch 01/11] mm: memcg: consolidate hierarchy iteration primitives Johannes Weiner
2011-09-12 22:37   ` Kirill A. Shutemov
2011-09-13  5:40     ` Johannes Weiner
2011-09-19 13:06     ` Michal Hocko
2011-09-13 10:06   ` KAMEZAWA Hiroyuki
2011-09-19 12:53   ` Michal Hocko
2011-09-20  8:45     ` Johannes Weiner
2011-09-20  8:53       ` Michal Hocko
2011-09-12 10:57 ` [patch 02/11] mm: vmscan: distinguish global reclaim from global LRU scanning Johannes Weiner
2011-09-12 23:02   ` Kirill A. Shutemov
2011-09-13  5:48     ` Johannes Weiner
2011-09-13 10:07   ` KAMEZAWA Hiroyuki
2011-09-19 13:23   ` Michal Hocko
2011-09-19 13:46     ` Michal Hocko
2011-09-20  8:52     ` Johannes Weiner
2011-09-12 10:57 ` [patch 03/11] mm: vmscan: distinguish between memcg triggering reclaim and memcg being scanned Johannes Weiner
2011-09-13 10:23   ` KAMEZAWA Hiroyuki
2011-09-19 14:29   ` Michal Hocko
2011-09-20  8:58     ` Johannes Weiner
2011-09-20  9:17       ` Michal Hocko
2011-09-29  7:55         ` Johannes Weiner
2011-09-12 10:57 ` [patch 04/11] mm: memcg: per-priority per-zone hierarchy scan generations Johannes Weiner
2011-09-13 10:27   ` KAMEZAWA Hiroyuki
2011-09-13 11:03     ` Johannes Weiner
2011-09-14  0:55       ` KAMEZAWA Hiroyuki
2011-09-14  5:56         ` Johannes Weiner
2011-09-14  7:40           ` KAMEZAWA Hiroyuki
2011-09-20  8:15       ` Michal Hocko
2011-09-20  8:45   ` Michal Hocko
2011-09-20  9:10     ` Johannes Weiner
2011-09-20 12:37       ` Michal Hocko
2011-09-12 10:57 ` [patch 05/11] mm: move memcg hierarchy reclaim to generic reclaim code Johannes Weiner
2011-09-13 10:31   ` KAMEZAWA Hiroyuki
2011-09-20 13:09   ` Michal Hocko
2011-09-20 13:29     ` Johannes Weiner
2011-09-20 14:08       ` Michal Hocko
2011-09-12 10:57 ` [patch 06/11] mm: memcg: remove optimization of keeping the root_mem_cgroup LRU lists empty Johannes Weiner
2011-09-13 10:34   ` KAMEZAWA Hiroyuki
2011-09-20 15:02   ` Michal Hocko
2011-09-29  9:20     ` Johannes Weiner
2011-09-29  9:49       ` Michal Hocko
2011-09-12 10:57 ` [patch 07/11] mm: vmscan: convert unevictable page rescue scanner to per-memcg LRU lists Johannes Weiner
2011-09-13 10:37   ` KAMEZAWA Hiroyuki
2011-09-21 12:33   ` Michal Hocko
2011-09-21 13:47     ` Johannes Weiner
2011-09-21 14:08       ` Michal Hocko
2011-09-12 10:57 ` [patch 08/11] mm: vmscan: convert global reclaim " Johannes Weiner
2011-09-13 10:41   ` KAMEZAWA Hiroyuki
2011-09-21 13:10   ` Michal Hocko
2011-09-21 13:51     ` Johannes Weiner [this message]
2011-09-21 13:57       ` Michal Hocko
2011-09-12 10:57 ` [patch 09/11] mm: collect LRU list heads into struct lruvec Johannes Weiner
2011-09-13 10:43   ` KAMEZAWA Hiroyuki
2011-09-21 13:43   ` Michal Hocko
2011-09-21 15:15     ` Michal Hocko
2011-09-12 10:57 ` [patch 10/11] mm: make per-memcg LRU lists exclusive Johannes Weiner
2011-09-13 10:47   ` KAMEZAWA Hiroyuki
2011-09-21 15:24   ` Michal Hocko
2011-09-21 15:47     ` Johannes Weiner
2011-09-21 16:05       ` Michal Hocko
2011-09-12 10:57 ` [patch 11/11] mm: memcg: remove unused node/section info from pc->flags Johannes Weiner
2011-09-13 10:50   ` KAMEZAWA Hiroyuki
2011-09-21 15:32   ` Michal Hocko
2011-09-13 20:35 ` [patch 0/11] mm: memcg naturalization -rc3 Kirill A. Shutemov

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