lkml.org 
[lkml]   [2007]   [Jan]   [12]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: tuning/tweaking VM settings for low memory (preventing OOM)
    Kumar Gala wrote:
    > 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?

    You don't give us the actual OOM message. In newer kernels, there has been
    quite a bit of work done to improve the OOM situation -- search changelogs
    in mm/oom_kill.c mm/vmscan.c mm/page_alloc.c.

    --
    SUSE Labs, Novell Inc.
    Send instant messages to your online friends http://au.messenger.yahoo.com

    -
    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/

    \
     
     \ /
      Last update: 2007-01-13 06:45    [W:0.036 / U:0.008 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site