lkml.org 
[lkml]   [2010]   [Dec]   [2]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: perf hw in kexeced kernel broken in tip
    On Thu, Dec 02, 2010 at 08:34:30AM +0100, Peter Zijlstra wrote:
    > On Thu, 2010-12-02 at 00:23 -0500, Don Zickus wrote:
    > > On Wed, Dec 01, 2010 at 01:48:07PM -0800, Eric W. Biederman wrote:
    > > > >
    > > > > Oh, but I'm not a device or sysdev thing, I'll never get something like
    > > > > that.
    > > >
    > > > There is also the reboot notifier, if the NMI needs to be controlled
    > > > outside of device model. Sigh. The NMI handling is such a special case.
    > >
    > > I tried reboot notifiers with the nmi_watchdog and acheived some success
    > > (on a Westmere box, a P4 still failed). Kdump is still screwed, but maybe
    > > we don't care for now.
    > >
    > > Here is the quick and dirty patch I used.
    >
    >
    > We'd really want a perf_event.c callback there to do as the hot-unplug
    > code does and detach all running counters from the cpu.

    Ok, I moved the reboot notifier stuff from kernel/watchdog.c to
    kernel/perf_event.c. Things still worked fine from a kexec perspective.

    Vivek suggested to me this morning that I should just blantantly disable the
    perf counter during init when running my test. Looking through the code I
    don't think I can do this using disable_all because some routines look for
    the active bit to be set and some arches have different disable registers
    than others. Thoughts?

    Cheers,
    Don


    \
     
     \ /
      Last update: 2010-12-02 17:17    [W:0.023 / U:30.532 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site