Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161108AbXALV6v (ORCPT ); Fri, 12 Jan 2007 16:58:51 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1161110AbXALV6v (ORCPT ); Fri, 12 Jan 2007 16:58:51 -0500 Received: from nommos.sslcatacombnetworking.com ([67.18.224.114]:6129 "EHLO nommos.sslcatacombnetworking.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1161108AbXALV6u (ORCPT ); Fri, 12 Jan 2007 16:58:50 -0500 Mime-Version: 1.0 (Apple Message framework v752.2) Content-Transfer-Encoding: 7bit Message-Id: Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed To: Linux Kernel list From: Kumar Gala Subject: tuning/tweaking VM settings for low memory (preventing OOM) Date: Fri, 12 Jan 2007 15:58:08 -0600 X-Mailer: Apple Mail (2.752.2) X-PopBeforeSMTPSenders: kumar-chaos@kgala.com,kumar-statements@kgala.com,kumar@kgala.com X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - nommos.sslcatacombnetworking.com X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [0 0] / [47 12] X-AntiAbuse: Sender Address Domain - kernel.crashing.org X-Source: X-Source-Args: X-Source-Dir: Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2146 Lines: 74 I'm working on an embedded PPC setup with 64M of memory and no swap. I'm trying to figure out how best to tune the VM for an OOM situation I'm running into. I'm running a 2.6.16.35 kernel and have a bittorrent app that appears to be initializing a large file for it to download into. What I see before running the app: /bigfoot/usb_disk # cat /proc/meminfo MemTotal: 62520 kB MemFree: 49192 kB Buffers: 8240 kB Cached: 740 kB SwapCached: 0 kB Active: 8196 kB Inactive: 1236 kB HighTotal: 0 kB HighFree: 0 kB LowTotal: 62520 kB LowFree: 49192 kB SwapTotal: 0 kB SwapFree: 0 kB Dirty: 0 kB Writeback: 0 kB Mapped: 916 kB Slab: 2224 kB CommitLimit: 31260 kB Committed_AS: 1704 kB PageTables: 88 kB VmallocTotal: 933872 kB VmallocUsed: 9416 kB VmallocChunk: 923628 kB after the OOM: /bigfoot/usb_disk # cat /proc/meminfo MemTotal: 62520 kB MemFree: 1608 kB Buffers: 8212 kB Cached: 42780 kB SwapCached: 0 kB Active: 6228 kB Inactive: 45176 kB HighTotal: 0 kB HighFree: 0 kB LowTotal: 62520 kB LowFree: 1608 kB SwapTotal: 0 kB SwapFree: 0 kB Dirty: 35208 kB Writeback: 5616 kB Mapped: 892 kB Slab: 7788 kB CommitLimit: 31260 kB Committed_AS: 1704 kB PageTables: 88 kB VmallocTotal: 933872 kB VmallocUsed: 9416 kB VmallocChunk: 923628 kB Which makes me think that we aren't writing back fast enough. If I mount the drive "sync" the issue clearly goes away. It appears from an strace we are doing ftruncate64(5, 178257920) when we OOM. Any ideas on VM parameters to tweak so we throttle this from occurring? - k - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/