On 15.03.2011, at 06:29, Bharat Bhushan wrote: > Following dump is observed on host when clearing the exit timing counters > > [root@p1021mds kvm]# echo -n 'c' > vm1200_vcpu0_timing > INFO: task echo:1276 blocked for more than 120 seconds. > "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. > echo D 0ff5bf94 0 1276 1190 0x00000000 > Call Trace: > [c2157e40] [c0007908] __switch_to+0x9c/0xc4 > [c2157e50] [c040293c] schedule+0x1b4/0x3bc > [c2157e90] [c04032dc] __mutex_lock_slowpath+0x74/0xc0 > [c2157ec0] [c00369e4] kvmppc_init_timing_stats+0x20/0xb8 > [c2157ed0] [c0036b00] kvmppc_exit_timing_write+0x84/0x98 > [c2157ef0] [c00b9f90] vfs_write+0xc0/0x16c > [c2157f10] [c00ba284] sys_write+0x4c/0x90 > [c2157f40] [c000e320] ret_from_syscall+0x0/0x3c > > The vcpu->mutex is used by kvm_ioctl_* (KVM_RUN etc) and same was > used when clearing the stats (in kvmppc_init_timing_stats()). What happens > is that when the guest is idle then it held the vcpu->mutx. While the > exiting timing process waits for guest to release the vcpu->mutex and > a hang state is reached. > > Now using seprate lock for exit timing stats. > > Signed-off-by: Bharat Bhushan <Bharat.Bhushan@xxxxxxxxxxxxx> Looks good from a 10000 feet perspective. My BookE box is currently down, so I can't test it, but I assume you have verified it works just fine? If so, please CC kvm@xxxxxxxxxxxxxxx, so Avi can take it in the tree with my signed-off (after I tested it ;)). 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
