lkml.org 
[lkml]   [2004]   [Nov]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [patch] Real-Time Preemption, -RT-2.6.10-rc1-mm3-V0.7.23

    * Karsten Wiese <annabellesgarden@yahoo.de> wrote:

    > Yes, it always happens, when callling ./cvscompile script of a
    > project, that is mounted via nfs. Haven't tried to do that
    > ./cvscompile locally, should I?

    very interesting, nfs is indeed one of the frequent BKL users.

    a 'BKL leak' is an unbalanced lock, e.g.:

    lock_kernel();
    ... do stuff ...
    if (error)
    return;
    ... do more stuff ...
    unlock_kernel();

    the BKL is a very special type of lock which fact has the side-effect
    that in the stock kernel a 'BKL leak' can go unnoticed very easily: it
    causes no problems other than hard-to-debug (but severe) scalability
    regressions. The moment the BKL count leaked from the NFS code that
    process has been 'scalability-poisoned' and will be handicapped until it
    exits.

    In the PREEMPT_RT patchset i added a strict locking checker to do_exit()
    that found this apparent NFS bug. Unfortunately the deadlock detector
    only reported a pretty common place where the BKL gets
    dropped/reacquired frequently so we dont know where the NFS code has the
    lock/unlock imbalance. Could you report this bug to the NFS maintainers
    (along with the above and the previous analysis)?

    Ingo
    -
    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: 2005-03-22 14:07    [W:4.213 / U:0.172 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site