lkml.org 
[lkml]   [2018]   [May]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [PATCH v2] schedutil: Allow cpufreq requests to be made even when kthread kicked
    On 22-05-18, 15:09, Joel Fernandes wrote:
    > I agree with the race you describe for single policy slow-switch. Good find :)
    >
    > The mainline sugov_work could also do such reordering in sugov_work, I think. Even
    > with the mutex_unlock in mainline's sugov_work, that work_in_progress write could
    > be reordered by the CPU to happen before the read of next_freq. AIUI,
    > mutex_unlock is expected to be only a release-barrier.
    >
    > Although to be safe, I could just put an smp_mb() there. I believe with that,
    > no locking would be needed for such case.
    >
    > I'll send out a v3 with Acks for the original patch, and the send out the
    > smp_mb() as a separate patch if that's Ok.

    Maybe it would be better to get the fix (with smp_mb) first and then
    this optimization patch on the top? That would mean that the fix can
    get applied to stable kernels easily.

    --
    viresh

    \
     
     \ /
      Last update: 2018-05-23 11:01    [W:2.524 / U:0.008 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site