On 03/16/2011 04:08 AM, Bhushan Bharat-R65777 wrote:
-----Original Message-----
From: Alexander Graf [mailto:agraf@xxxxxxx]
Sent: Tuesday, March 15, 2011 8:11 PM
To: Bhushan Bharat-R65777
Cc: kvm-ppc@xxxxxxxxxxxxxxx; bharatb.yadav@xxxxxxxxx; Bhushan Bharat-
R65777
Subject: Re: [PATCH] Issue in exit timing clearance
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 ;)).
Hi Alex,
I have tested this and works fine for me.
Please let me know when you complete your testing so that I send to kvm@xxxxxxxxxxxxxxxx
Works for me.
Acked-by: Alexander Graf <agraf@xxxxxxx>
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
