Re: 3.12-rcX - NFS regression - kswapd0 / kswapd1 stays using 100%CPU?

From: Myklebust, Trond
Date: Fri Oct 18 2013 - 16:12:23 EST


On Fri, 2013-10-18 at 22:03 +-0200, Helge Deller wrote:
+AD4- On 10/18/2013 09:36 PM, Myklebust, Trond wrote:
+AD4- +AD4- Also, could you please try a sysRQ-t the next time it happens, so that
+AD4- +AD4- we can get a trace of where the mount program is hanging. Knowing that
+AD4- +AD4- the mount is stuck in +ACIAXwBf-schedule()+ACI- is not really interesting unless we
+AD4- +AD4- know from where that was called.
+AD4-
+AD4- Actually, the machine was still running in this state.
+AD4- Here is sysrq-t:
+AD4- +AFs-112009.084000+AF0- mount S 00000000401040c0 0 25331 1 0x00000010
+AD4- +AFs-112009.084000+AF0- Backtrace:
+AD4- +AFs-112009.084000+AF0- +AFsAPA-0000000040113a68+AD4AXQ- +AF8AXw-schedule+0x500/0x810-
+AD4- +AFs-112009.232000+AF0-
+AD4- +AFs-112009.232000+AF0- mount.nfs D 00000000401040c0 0 25332 25331 0x00000010
+AD4- +AFs-112009.232000+AF0- Backtrace:
+AD4- +AFs-112009.232000+AF0- +AFsAPA-0000000040113a68+AD4AXQ- +AF8AXw-schedule+0x500/0x810-

That makes no sense unless sysrq-t works differently on parisc than on
other platforms. I'd expect the backtrace to at least include a system
call. Parisc experts?

--
Trond Myklebust
Linux NFS client maintainer

NetApp
Trond.Myklebust+AEA-netapp.com
www.netapp.com
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