From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wi0-f179.google.com (mail-wi0-f179.google.com [209.85.212.179]) by kanga.kvack.org (Postfix) with ESMTP id 1E0B76B0038 for ; Wed, 8 Jul 2015 16:43:44 -0400 (EDT) Received: by widjy10 with SMTP id jy10so227580277wid.1 for ; Wed, 08 Jul 2015 13:43:43 -0700 (PDT) Received: from arcturus.aphlor.org (arcturus.ipv6.aphlor.org. [2a03:9800:10:4a::2]) by mx.google.com with ESMTPS id bu10si5994736wjc.55.2015.07.08.13.43.41 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 08 Jul 2015 13:43:42 -0700 (PDT) Received: from [209.6.119.210] (helo=wopr.kernelslacker.org) by arcturus.aphlor.org with esmtpsa (TLSv1.2:DHE-RSA-AES256-GCM-SHA384:256) (Exim 4.84) (envelope-from ) id 1ZCwBq-0005mj-Fm for linux-mm@kvack.org; Wed, 08 Jul 2015 21:43:34 +0100 Date: Wed, 8 Jul 2015 16:43:34 -0400 From: Dave Jones Subject: 4.2rc1 odd looking page allocator failure stats Message-ID: <20150708204334.GA15602@codemonkey.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Sender: owner-linux-mm@kvack.org List-ID: To: linux-mm@kvack.org I've got a box with 4GB of RAM that I've driven into oom (so much so that e1000 can't alloc a single page, so I can't even ping it). But over serial console I noticed this.. [158831.710001] DMA32 free:1624kB min:6880kB low:8600kB high:10320kB active_anon:407004kB inactive_anon:799300kB active_file:516kB inactive_file:6644kB unevictable:0kB isolated(anon):0kB isolated(file):0kB present:3127220kB managed:3043108kB mlocked:0kB dirty:6680kB writeback:64kB mapped:31544kB shmem:1146792kB slab_reclaimable:46812kB slab_unreclaimable:388364kB kernel_stack:2288kB pagetables:2076kB unstable:0kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB writeback_tmp:0kB pages_scanned:70152496980 all_unreclaimable? yes How come that 'pages_scanned' number is greater than the number of pages in the system ? Does kswapd iterate over the same pages a number of times each time the page allocator fails ? I've managed to hit this a couple times this week, where the oom killer kicks in, kills some processes, but then the machine goes into a death spiral of looping in the page allocator. Once that begins, it never tries to oom kill again, just hours of page allocation failure messages. Dave -- 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