Messages in this thread | | | From | KOSAKI Motohiro <> | Subject | Re: [PATCH for mmotm 0/5] introduce swap-backed-file-mapped count and fix vmscan-change-the-number-of-the-unmapped-files-in-zone-reclaim.patch | Date | Thu, 11 Jun 2009 20:32:23 +0900 (JST) |
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> On Thu, Jun 11, 2009 at 07:42:33PM +0900, KOSAKI Motohiro wrote: > > > On Thu, Jun 11, 2009 at 07:25:09PM +0900, KOSAKI Motohiro wrote: > > > > Recently, Wu Fengguang pointed out vmscan-change-the-number-of-the-unmapped-files-in-zone-reclaim.patch > > > > has underflow problem. > > > > > > > > > > Can you drop this aspect of the patchset please? I'm doing a final test > > > on the scan-avoidance heuristic that incorporates this patch and the > > > underflow fix. Ram (the tester of the malloc()-stall) confirms the patch > > > fixes his problem. > > > > OK. > > insted, I'll join to review your patch :) > > > > Thanks. You should have it now. In particular, I'm interested in hearing you > opinion about patch 1 of the series "Fix malloc() stall in zone_reclaim() > and bring behaviour more in line with expectations V3" and if addresses; > > 1. Does patch 1 address the problem that first led you to develop the patch > vmscan-change-the-number-of-the-unmapped-files-in-zone-reclaim.patch?
Yes, thanks. my original issue is
1. mem-hog process eat all pages in one node of numa machine. 2. kswapd run and makes many swapcache. it mean increasing NR_FILE_PAGES - NR_FILE_MAPPED. 3. any page allocation invoke zone reclaim, but the zone don't have any file-backed page at all.
distro kernel can reproduce easily, but mainline kernel can't so easy. but I think root cause is remain. it is (NR_FILE_PAGES - NR_FILE_MAPPED) calculation.
> 2. Do you think patch 1 should merge with and replace > vmscan-change-the-number-of-the-unmapped-files-in-zone-reclaim.patch?
In my personal prefer, your patch seems to have very good description and rewrite almost part of mine. Thus replacing is better. Can you please make replacing patch?
> > > > This patch series introduce new vmstat of swap-backed-file-mapped and fix above > > > > patch by it. > > > > I don't think the patch above needs to be fixed by another counter. At > least, once the underflow was fixed up, it handled the malloc-stall without > additional counters. If we need to account swap-backed-file-mapped, we need > another failure case that it addresses to be sure we're doing the right thing.
ok, I drop this.
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