Messages in this thread | | | Date | Wed, 09 May 2012 12:08:51 +0530 | From | Anshuman Khandual <> | Subject | Re: [PATCH 2/9] perf: Allow pmu to choose cpu on which to install event |
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On Wednesday 02 May 2012 07:37 AM, Yan, Zheng wrote:
> From: "Yan, Zheng" <zheng.z.yan@intel.com> > > Allow the pmu->event_init callback to change event->cpu, so pmu can > choose cpu on which to install event. > > Signed-off-by: Zheng Yan <zheng.z.yan@intel.com> > --- > kernel/events/core.c | 13 +++++++++---- > 1 files changed, 9 insertions(+), 4 deletions(-) > > diff --git a/kernel/events/core.c b/kernel/events/core.c > index 32cfc76..84911de 100644 > --- a/kernel/events/core.c > +++ b/kernel/events/core.c > @@ -6250,6 +6250,8 @@ SYSCALL_DEFINE5(perf_event_open, > } > } > > + get_online_cpus();
Why this protection against cpu hotplug operation ? Is this because PMU now can change event->cpu during event initialization (specific to uncore PMU events) or this protection has always been required for normal on-cpu HW PMU events also and we added it right now ?
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