* Finding out who's holding a lock?
@ 2013-08-23 0:52 Andy Lutomirski
2013-08-24 10:50 ` Peter Hurley
0 siblings, 1 reply; 2+ messages in thread
From: Andy Lutomirski @ 2013-08-23 0:52 UTC (permalink / raw)
To: linux-kernel@vger.kernel.org
My program is occasionally seeing slow page faults. latencytop says
they're slow because they're waiting for read access to mmap_sem, but
latencytop isn't showing any other thread in the process blocking.
Is there any straightforward way to find out who called down_write on
mmap_sem when down_read is slow?
--Andy
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: Finding out who's holding a lock?
2013-08-23 0:52 Finding out who's holding a lock? Andy Lutomirski
@ 2013-08-24 10:50 ` Peter Hurley
0 siblings, 0 replies; 2+ messages in thread
From: Peter Hurley @ 2013-08-24 10:50 UTC (permalink / raw)
To: Andy Lutomirski; +Cc: linux-kernel@vger.kernel.org
On 08/22/2013 08:52 PM, Andy Lutomirski wrote:
> My program is occasionally seeing slow page faults. latencytop says
> they're slow because they're waiting for read access to mmap_sem, but
> latencytop isn't showing any other thread in the process blocking.
>
> Is there any straightforward way to find out who called down_write on
> mmap_sem when down_read is slow?
Build with CONFIG_LOCKDEP (Kernel Debugging -> Lock Debugging ->
"Lock Debugging: prove locking correctness").
When you experience the slowdown, sysrq + d (displays all currently
held locks). sysrq can also be programmatically triggered with
"echo d > /proc/sysrq-trigger" or equivalent.
Regards,
Peter Hurley
^ permalink raw reply [flat|nested] 2+ messages in thread
end of thread, other threads:[~2013-08-24 10:50 UTC | newest]
Thread overview: 2+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2013-08-23 0:52 Finding out who's holding a lock? Andy Lutomirski
2013-08-24 10:50 ` Peter Hurley
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox