nmi_watchdog: support for oprofile
Re-arrange the code so that when someone disables nmi_watchdog with: echo 0 > /proc/sys/kernel/nmi_watchdog it releases the hardware reservation on the PMUs. This allows the oprofile module to grab those PMUs and do its thing. Otherwise oprofile fails to load because the hardware is reserved by the perf_events subsystem. Tested using: oprofile --vm-linux --start and watched it failed when nmi_watchdog is enabled and succeed when: oprofile --deinit && echo 0 > /proc/sys/kernel/nmi_watchdog is run. Note: this has the side quirk of having the nmi_watchdog latch onto the software events instead of hardware events if oprofile has already reserved the hardware first. User beware! :-) Signed-off-by: NDon Zickus <dzickus@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: gorcunov@gmail.com Cc: aris@redhat.com Cc: eranian@google.com LKML-Reference: <1266357892-30504-1-git-send-email-dzickus@redhat.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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