lkml.org 
[lkml]   [2007]   [Sep]   [28]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: A unresponsive file system can hang all I/O in the system on linux-2.6.23-rc6 (dirty_thresh problem?)
    Thanks.

    The BDI dirty limits sounds like a good idea.

    Is there already a patch for this, which I could try?

    I believe it works like this,

    Each BDI, will have a limit. If the dirty_thresh exceeds the limit,
    all the I/O on the block device will be synchronous.

    so, if I have sda & a NFS mount, the dirty limit can be different for
    each of them.

    I can set dirty limit for
    - sda to be 90% and
    - NFS mount to be 50%.

    So, if the dirty limit is greater than 50%, NFS does synchronously,
    but sda can work asynchronously, till dirty limit reaches 90%.

    Thanks
    --Chakri

    On 9/27/07, Peter Zijlstra <a.p.zijlstra@chello.nl> wrote:
    > On Thu, 2007-09-27 at 23:50 -0700, Andrew Morton wrote:
    >
    > > What we _don't_ want to happen is for other processes which are writing to
    > > other, non-dead devices to get collaterally blocked. We have patches which
    > > might fix that queued for 2.6.24. Peter?
    >
    > Nasty problem, don't do that :-)
    >
    > But yeah, with per BDI dirty limits we get stuck at whatever ratio that
    > NFS server/mount (?) has - which could be 100%. Other processes will
    > then work almost synchronously against their BDIs but it should work.
    >
    > [ They will lower the NFS-BDI's ratio, but some fancy clipping code will
    > limit the other BDIs their dirty limit to not exceed the total limit.
    > And with all these NFS pages stuck, that will still be nothing. ]
    >
    >
    >
    >
    -
    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: 2007-09-28 10:29    [W:0.035 / U:29.852 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site