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| author | Bharat Bhushan <r65777@freescale.com> | 2011-03-25 10:32:13 +0530 |
|---|---|---|
| committer | Avi Kivity <avi@redhat.com> | 2011-05-11 07:57:04 -0400 |
| commit | 09000adb86550d2895b64faa52e64eaec3cae7b2 (patch) | |
| tree | e2a932b4735b1296e2df760fea26030286f9daaa /arch/powerpc/include | |
| parent | 7c5625227ff8c81953e953d8e25c3eba2ab0aeb3 (diff) | |
| download | linux-09000adb86550d2895b64faa52e64eaec3cae7b2.tar.gz linux-09000adb86550d2895b64faa52e64eaec3cae7b2.tar.bz2 linux-09000adb86550d2895b64faa52e64eaec3cae7b2.zip | |
KVM: PPC: Fix issue clearing exit timing counters
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@freescale.com>
Acked-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
Diffstat (limited to 'arch/powerpc/include')
| -rw-r--r-- | arch/powerpc/include/asm/kvm_host.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h index bba3b9b72a39..890897cee050 100644 --- a/arch/powerpc/include/asm/kvm_host.h +++ b/arch/powerpc/include/asm/kvm_host.h @@ -255,6 +255,7 @@ struct kvm_vcpu_arch { u32 dbsr; #ifdef CONFIG_KVM_EXIT_TIMING + struct mutex exit_timing_lock; struct kvmppc_exit_timing timing_exit; struct kvmppc_exit_timing timing_last_enter; u32 last_exit_type; |