From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from digeo-nav01.digeo.com (digeo-nav01.digeo.com [192.168.1.233]) by packet.digeo.com (8.9.3+Sun/8.9.3) with SMTP id RAA18761 for ; Mon, 9 Sep 2002 17:02:37 -0700 (PDT) Message-ID: <3D7D3697.1DE602D1@digeo.com> Date: Mon, 09 Sep 2002 17:02:31 -0700 From: Andrew Morton MIME-Version: 1.0 Subject: Re: [PATCH] modified segq for 2.5 References: <3D7C6C0A.1BBEBB2D@digeo.com> <3D7D277E.7E179FA0@digeo.com> <20020909234044.GJ18800@holomorphy.com> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: William Lee Irwin III Cc: Daniel Phillips , Rik van Riel , sfkaplan@cs.amherst.edu, linux-mm@kvack.org List-ID: William Lee Irwin III wrote: > > On Mon, Sep 09, 2002 at 03:58:06PM -0700, Andrew Morton wrote: > > This logic is too global at present. It really needs to be per-zone, > > to fix an oom problem which you-know-who managed to trigger. All > > ZONE_NORMAL is dirty, we keep on getting woken up by IO completion in > > ZONE_HIGHMEM, we end up scanning enough ZONE_NORMAL pages to conclude > > that we're oom. (Plus I reduced the maximum-scan-before-oom by 2.5x) > > Then again, Bill had twiddled the dirty memory thresholds > > to permit 12G of dirty ZONE_HIGHMEM. > > This seemed to work fine when I just tweaked problem areas to use > __GFP_NOKILL. mempool was fixed by the __GFP_FS checks, but > generic_file_read(), generic_file_write(), the rest of filemap.c, > slab allocations, and allocating file descriptor tables for poll() and > select() appeared to generate OOM when it appeared to me that failing > system calls with -ENOMEM was a better alternative than shooting tasks. But clearly there is reclaimable pagecache down there; we just have to wait for it. No idea why you'd get an oom on ZONE_HIGHMEM, but when I have a few more gigs I might be able to say. Anyway, it's all too much scanning. You'll probably find that segq helps by accident. I installed SEGQ (and the shrink-slab-harder-if-mapped-pages-are-enountered) on my desktop here. Initial indications are that SEGQ kicks butt. -- 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/