Re: [PATCH] vmscan: skip freeing memory from zones with lots free
From: Rik van Riel
Date: Sat Nov 29 2008 - 12:58:52 EST
Andrew Morton wrote:
On Sat, 29 Nov 2008 11:47:25 -0500 Rik van Riel <riel@xxxxxxxxxx> 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.
No, kswapd calls shrink_zone directly from balance_pgdat,
it does not go through shrink_zones.
commit 26e4931632352e3c95a61edac22d12ebb72038fe
Author: akpm <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?
Googling on 26e4931632352e3c95a61edac22d12ebb72038fe only finds
your emails with that commit id in it - which git tree do I
need to search to get that changeset?
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