lkml.org 
[lkml]   [2009]   [Mar]   [22]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    Date
    From
    SubjectRe: 2.6.28, limiting cpu time doesn't work
    On 03/19, Peter Lojkin wrote:
    >
    > after upgrade to 2.6.28 ulimit -t doesn't work. for example:
    >
    > bash# ulimit -t 3; cpuhog
    >
    > (where cpuhog is any program that continuously use cpu)
    > with 2.6.27.20 cpuhog gets killed after 3sec as expected.
    > with 2.6.28, 2.6.28.8, 2.6.29-rc8-git4 it's keep running indefinitely.
    > ulimit -a and /proc/<pid>/limits show that cputime limit was set correctly.

    Found this message on http://bugzilla.kernel.org/show_bug.cgi?id=12911 ...

    I _think_ posix_cpu_timers_init_group() is not right, it should copy
    cputime_expires->prof_exp.

    Peter, any chance you can test the (uncompiled/untested) patch below?

    Also, I assume that something like

    $ ulimit -t 3
    $ while true; do true; done

    kills the shell correctly, yes? IOW, I suspect that ulimit works, but
    cpuhog never check RLIMIT_CPU because fastpath_timer_check() always
    returns 0 due to task_cputime_zero(&sig->cputime_expires) == T.

    I'm afraid we need the fix fo 2.6.29 as well, but I am looking at rc3.

    Hmm. check_process_timers() updates ->cputime_expires, but it never
    clears (say) cputime_expires.prof_exp, why? Can't we just do

    if (cputime_gt(sig->cputime_expires.prof_exp, prof_expires))
    sig->cputime_expires.prof_exp = prof_expires;
    at the end?

    Oleg.

    --- a/kernel/fork.c
    +++ b/kernel/fork.c
    @@ -790,9 +790,7 @@ static void posix_cpu_timers_init_group(
    sig->it_prof_incr = cputime_zero;

    /* Cached expiration times. */
    - sig->cputime_expires.prof_exp = cputime_zero;
    - sig->cputime_expires.virt_exp = cputime_zero;
    - sig->cputime_expires.sched_exp = 0;
    + sig->cputime_expires = current->signal->cputime_expires;

    /* The timer lists. */
    INIT_LIST_HEAD(&sig->cpu_timers[0]);


    \
     
     \ /
      Last update: 2009-03-22 21:21    [W:0.021 / U:60.868 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site