On 05/26/2017 10:05 AM, Jan Beulich wrote: >>>> On 22.05.17 at 22:45, <luwei.k...@intel.com> wrote: >> Currently, Hot unplug a physical CPU with vpmu enabled may cause >> system hang due to send a remote call to an offlined pCPU. This >> patch add a cpu hot unplug notifer to save vpmu context before >> cpu offline. >> >> Consider one scenario, hot unplug pCPU N with vpmu enabled. >> The vcpu which running on this pCPU will be switch to other >> online cpu. A remote call will be send to pCPU N to save the >> vpmu context before loading the vpmu context on this pCPU. >> System will hang in function on_select_cpus() because of that >> pCPU is offlined and can not do any respond. >> >> The purpose of add a VPMU_CONTEXT_LOADED check in vpmu_arch_destroy() >> before send a remote call to save vpmu contex is: >> a. when a vpmu context has been loaded in a remote pCPU, make a >> remote call to save the vpmu contex and stop counters is necessary. >> b. VPMU_CONTEXT_LOADED flag will be reset if a pCPU is offlined. >> this check will prevent send a remote call to an offlined pCPU. >> >> Signed-off-by: Luwei Kang <luwei.k...@intel.com> > Acked-by: Jan Beulich <jbeul...@suse.com> > partly on the basis that Boris had agreed with how the change > is being done, so Boris, an R-b from you would be nice.
Reviewed-by: Boris Ostrovsky <boris.ostrov...@oracle.com> _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org https://lists.xen.org/xen-devel
