From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexander Graf Date: Wed, 16 Mar 2011 14:14:27 +0000 Subject: Re: [PATCH] Issue in exit timing clearance Message-Id: <4D80C5C3.5090601@suse.de> List-Id: References: <1300083877-8672-1-git-send-email-Bharat.Bhushan@freescale.com> In-Reply-To: <1300083877-8672-1-git-send-email-Bharat.Bhushan@freescale.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: kvm-ppc@vger.kernel.org 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 >> 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 Alex