On 16.11.2013, at 01:55, Paul Mackerras <paulus@xxxxxxxxx> wrote: > On Fri, Nov 15, 2013 at 04:35:00PM +0800, Liu Ping Fan wrote: >> Since kvmppc_hv_find_lock_hpte() is called from both virtmode and >> realmode, so it can trigger the deadlock. >> >> Suppose the following scene: >> >> Two physical cpuM, cpuN, two VM instances A, B, each VM has a group of >> vcpus. >> >> If on cpuM, vcpu_A_1 holds bitlock X (HPTE_V_HVLOCK), then is switched >> out, and on cpuN, vcpu_A_2 try to lock X in realmode, then cpuN will be >> caught in realmode for a long time. >> >> What makes things even worse if the following happens, >> On cpuM, bitlockX is hold, on cpuN, Y is hold. >> vcpu_B_2 try to lock Y on cpuM in realmode >> vcpu_A_2 try to lock X on cpuN in realmode >> >> Oops! deadlock happens >> >> Signed-off-by: Liu Ping Fan <pingfank@xxxxxxxxxxxxxxxxxx> > > Reviewed-by: Paul Mackerras <paulus@xxxxxxxxx> Thanks, applied to kvm-ppc-queue. Alex -- To unsubscribe from this list: send the line "unsubscribe kvm-ppc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
