From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Sat, 29 Nov 2008 09:45:37 -0800 From: Andrew Morton Subject: Re: [PATCH] vmscan: skip freeing memory from zones with lots free Message-Id: <20081129094537.a224098a.akpm@linux-foundation.org> In-Reply-To: <4931721D.7010001@redhat.com> References: <20081128060803.73cd59bd@bree.surriel.com> <20081128231933.8daef193.akpm@linux-foundation.org> <4931721D.7010001@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Rik van Riel Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, KOSAKI Motohiro List-ID: On Sat, 29 Nov 2008 11:47:25 -0500 Rik van Riel wrote: > Andrew Morton wrote: > > >> Index: linux-2.6.28-rc5/mm/vmscan.c > >> =================================================================== > >> --- linux-2.6.28-rc5.orig/mm/vmscan.c 2008-11-28 05:53:56.000000000 -0500 > >> +++ linux-2.6.28-rc5/mm/vmscan.c 2008-11-28 06:05:29.000000000 -0500 > >> @@ -1510,6 +1510,9 @@ static unsigned long shrink_zones(int pr > >> if (zone_is_all_unreclaimable(zone) && > >> priority != DEF_PRIORITY) > >> continue; /* Let kswapd poll it */ > >> + if (zone_watermark_ok(zone, sc->order, > >> + 4*zone->pages_high, high_zoneidx, 0)) > >> + continue; /* Lots free already */ > >> sc->all_unreclaimable = 0; > >> } else { > >> /* > > > > We already tried this, or something very similar in effect, I think... > > Yes, we have a check just like this in balance_pgdat(). > > It's been there forever with no ill effect. This patch affects direct reclaim as well as kswapd. > > commit 26e4931632352e3c95a61edac22d12ebb72038fe > > Author: akpm > > Date: Sun Sep 8 19:21:55 2002 +0000 > > > > [PATCH] refill the inactive list more quickly > > > > Fix a problem noticed by Ed Tomlinson: under shifting workloads the > > shrink_zone() logic will refill the inactive load too slowly. > > > > Bale out of the zone scan when we've reclaimed enough pages. Fixes a > > rarely-occurring problem wherein refill_inactive_zone() ends up > > shuffling 100,000 pages and generally goes silly. > > This is not a bale out, this is a "skip zones that have way > too many free pages already". It is similar in effect. Will this new patch reintroduce the problem which 26e4931632352e3c95a61edac22d12ebb72038fe fixed? -- 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/ . Don't email: email@kvack.org