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authorDavid Vrabel <david.vrabel@citrix.com>2013-06-27 11:35:44 +0100
committerThomas Gleixner <tglx@linutronix.de>2013-06-28 23:15:06 +0200
commit7c4c3a0f18ba57ea2a2985034532303d2929902a (patch)
tree553f2901ae4fd0fede367ece9ec9c30106ff744f /drivers/xen/manage.c
parent9e04d3804d3ac97d8c03a41d78d0f0674b5d01e1 (diff)
hrtimers: Support resuming with two or more CPUs online (but stopped)
hrtimers_resume() only reprograms the timers for the current CPU as it assumes that all other CPUs are offline at this point in the resume process. If other CPUs are online then their timers will not be corrected and they may fire at the wrong time. When running as a Xen guest, this assumption is not true. Non-boot CPUs are only stopped with IRQs disabled instead of offlining them. This is a performance optimization as disabling the CPUs would add an unacceptable amount of additional downtime during a live migration (> 200 ms for a 4 VCPU guest). hrtimers_resume() cannot call on_each_cpu(retrigger_next_event,...) as the other CPUs will be stopped with IRQs disabled. Instead, defer the call to the next softirq. [ tglx: Separated the xen change out ] Signed-off-by: David Vrabel <david.vrabel@citrix.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: John Stultz <john.stultz@linaro.org> Cc: <xen-devel@lists.xen.org> Link: http://lkml.kernel.org/r/1372329348-20841-2-git-send-email-david.vrabel@citrix.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'drivers/xen/manage.c')
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