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From: Michal Hocko <mhocko@suse.cz>
To: linux-mm@kvack.org
Cc: Ying Han <yinghan@google.com>,
	Johannes Weiner <hannes@cmpxchg.org>,
	KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
	Rik van Riel <riel@redhat.com>, Hugh Dickins <hughd@google.com>,
	Mel Gorman <mgorman@suse.de>,
	Glauber Costa <glommer@parallels.com>
Subject: Re: [RFC 0/3] soft reclaim rework
Date: Tue, 9 Apr 2013 17:37:42 +0200	[thread overview]
Message-ID: <20130409153742.GL29860@dhcp22.suse.cz> (raw)
In-Reply-To: <1365509595-665-1-git-send-email-mhocko@suse.cz>

On Tue 09-04-13 14:13:12, Michal Hocko wrote:
[...]
> 2) kbuild test showed more or less the same results
> usage_in_bytes
> Base
> 		Group A		Group B
> Median		394817536	395634688
> 
> Patches applied
> median		483481600	302131200
> 
> A is kept closer to the soft limit again. There is some fluctuation
> around the limit because kbuild creates a lot of short lived processes.
> Base: 	 pgscan_kswapd_dma32 1648718	pgsteal_kswapd_dma32 1510749
> Patched: pgscan_kswapd_dma32 2042065	pgsteal_kswapd_dma32 1667745

OK, so I have patched the base version with the patch bellow which
uncovers soft reclaim scanning and reclaim and guess what:
Base:	 pgscan_kswapd_dma32 3710092	pgsteal_kswapd_dma32 3225191
Patched: pgscan_kswapd_dma32 1846700	pgsteal_kswapd_dma32 1442232
Base:	 pgscan_direct_dma32 2417683	pgsteal_direct_dma32 459702
Patched: pgscan_direct_dma32 1839331	pgsteal_direct_dma32 244338

The numbers are obviously timing dependent (wrt. previous run ~10% for
the patched kernel) but the ~1/2 half wrt. the base kernel seems real
we just haven't seen it previously because it wasn't accounted. I guess
this can be attributed to prio-0 soft reclaim behavior and a lot of
dirty pages on the LRU.

> The differences are much bigger now so it would be interesting how much
> has been scanned/reclaimed during soft reclaim in the base kernel.
---

  parent reply	other threads:[~2013-04-09 15:37 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-04-09 12:13 Michal Hocko
2013-04-09 12:13 ` [RFC 1/3] memcg: integrate soft reclaim tighter with zone shrinking code Michal Hocko
2013-04-09 13:08   ` Johannes Weiner
2013-04-09 13:31     ` Michal Hocko
2013-04-09 13:57   ` Glauber Costa
2013-04-09 14:22     ` Michal Hocko
2013-04-09 16:45   ` Kamezawa Hiroyuki
2013-04-09 17:05     ` Michal Hocko
2013-04-14  0:42   ` Mel Gorman
2013-04-14 14:34     ` Michal Hocko
2013-04-14 14:55       ` Johannes Weiner
2013-04-14 15:04         ` Michal Hocko
2013-04-14 15:11           ` Michal Hocko
2013-04-14 18:03           ` Rik van Riel
2013-04-09 12:13 ` [RFC 2/3] memcg: Ignore soft limit until it is explicitly specified Michal Hocko
2013-04-09 13:24   ` Johannes Weiner
2013-04-09 13:42     ` Michal Hocko
2013-04-09 17:10   ` Kamezawa Hiroyuki
2013-04-09 17:22     ` Michal Hocko
2013-04-09 12:13 ` [RFC 3/3] vmscan, memcg: Do softlimit reclaim also for targeted reclaim Michal Hocko
2013-04-22  2:14   ` Michal Hocko
2013-04-09 15:37 ` Michal Hocko [this message]
2013-04-09 15:50   ` [RFC 0/3] soft reclaim rework Michal Hocko
2013-04-11  8:43 ` Michal Hocko
2013-04-11  9:07   ` Michal Hocko
2013-04-11 13:04   ` Michal Hocko
2013-04-17 22:52 ` Ying Han

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