From: Alexander Graf <agraf@suse.de>
To: kvm-ppc@vger.kernel.org
Subject: Re: [PATCH] Issue in exit timing clearance
Date: Wed, 16 Mar 2011 14:14:27 +0000 [thread overview]
Message-ID: <4D80C5C3.5090601@suse.de> (raw)
In-Reply-To: <1300083877-8672-1-git-send-email-Bharat.Bhushan@freescale.com>
On 03/16/2011 04:08 AM, Bhushan Bharat-R65777 wrote:
>
>> -----Original Message-----
>> From: Alexander Graf [mailto:agraf@suse.de]
>> Sent: Tuesday, March 15, 2011 8:11 PM
>> To: Bhushan Bharat-R65777
>> Cc: kvm-ppc@vger.kernel.org; bharatb.yadav@gmail.com; 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@freescale.com>
>> 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@vger.kernel.org, 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@vger.kernel.org.
Works for me.
Acked-by: Alexander Graf <agraf@suse.de>
Alex
prev parent reply other threads:[~2011-03-16 14:14 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-03-14 6:36 [PATCH] Issue in exit timing clearance Bharat Bhushan
2011-03-14 6:57 ` Bharat Bhushan
2011-03-15 5:41 ` Bharat Bhushan
2011-03-15 14:41 ` Alexander Graf
2011-03-16 3:08 ` Bhushan Bharat-R65777
2011-03-16 14:14 ` Alexander Graf [this message]
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