From: Rik van Riel <riel@redhat.com>
To: Michal Hocko <mhocko@suse.cz>
Cc: Ying Han <yinghan@google.com>,
Johannes Weiner <hannes@cmpxchg.org>, Mel Gorman <mel@csn.ul.ie>,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
Hillf Danton <dhillf@gmail.com>, Hugh Dickins <hughd@google.com>,
KOSAKI Motohiro <kosaki.motohiro@gmail.com>,
Andrew Morton <akpm@linux-foundation.org>,
linux-mm@kvack.org
Subject: Re: [PATCH V8 1/2] mm: memcg softlimit reclaim rework
Date: Fri, 03 Aug 2012 12:16:18 -0400 [thread overview]
Message-ID: <501BF952.7070202@redhat.com> (raw)
In-Reply-To: <20120803152234.GE8434@dhcp22.suse.cz>
On 08/03/2012 11:22 AM, Michal Hocko wrote:
> On Thu 02-08-12 14:24:18, Ying Han wrote:
> [...]
>> diff --git a/mm/vmscan.c b/mm/vmscan.c
>> index 3e0d0cd..88487b3 100644
>> --- a/mm/vmscan.c
>> +++ b/mm/vmscan.c
>> @@ -1866,7 +1866,22 @@ static void shrink_zone(struct zone *zone, struct scan_control *sc)
>> do {
>> struct lruvec *lruvec = mem_cgroup_zone_lruvec(zone, memcg);
>>
>> - shrink_lruvec(lruvec, sc);
>> + /*
>> + * Reclaim from mem_cgroup if any of these conditions are met:
>> + * - this is a targetted reclaim ( not global reclaim)
>> + * - reclaim priority is less than DEF_PRIORITY
>> + * - mem_cgroup or its ancestor ( not including root cgroup)
>> + * exceeds its soft limit
>> + *
>> + * Note: The priority check is a balance of how hard to
>> + * preserve the pages under softlimit. If the memcgs of the
>> + * zone having trouble to reclaim pages above their softlimit,
>> + * we have to reclaim under softlimit instead of burning more
>> + * cpu cycles.
>> + */
>> + if (!global_reclaim(sc) || sc->priority< DEF_PRIORITY ||
>> + mem_cgroup_over_soft_limit(memcg))
>> + shrink_lruvec(lruvec, sc);
>>
>> /*
>> * Limit reclaim has historically picked one memcg and
>
> I am thinking that we could add a constant for the priority
> limit. Something like
> #define MEMCG_LOW_SOFTLIMIT_PRIORITY DEF_PRIORITY
>
> Although it doesn't seem necessary at the moment, because there is just
> one location where it matters but it could help in the future.
> What do you think?
I am working on changing the code to find the "highest priority"
LRU and reclaim from that list first. That will obviate the need
for such a change. However, the other cleanups and simplifications
made by Ying's patch are good to have...
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next prev parent reply other threads:[~2012-08-03 16:16 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-02 21:24 [PATCH V8 1/2] mm: memcg softlimit reclaim rework Ying Han
2012-08-03 15:22 ` Michal Hocko
2012-08-03 16:16 ` Rik van Riel [this message]
2012-08-03 16:34 ` Ying Han
2012-08-06 13:33 ` Michal Hocko
2012-08-17 22:03 ` Ying Han
2012-08-20 8:03 ` Glauber Costa
2012-08-20 18:30 ` Ying Han
2012-08-21 9:29 ` Glauber Costa
2012-08-22 22:27 ` Ying Han
2012-08-23 7:49 ` Glauber Costa
2012-08-20 13:19 ` Kamezawa Hiroyuki
2012-08-20 18:12 ` Ying Han
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