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 <pingf...@linux.vnet.ibm.com>
Reviewed-by: Paul Mackerras <pau...@samba.org> _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
