From: Peter Hurley <peter@hurleysoftware.com>
To: Andy Lutomirski <luto@amacapital.net>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: Finding out who's holding a lock?
Date: Sat, 24 Aug 2013 06:50:45 -0400 [thread overview]
Message-ID: <52189005.30009@hurleysoftware.com> (raw)
In-Reply-To: <CALCETrUobqJKGCma_8=qsG=w3Tm3=ttZB==DwdHyGBkJDBYV_g@mail.gmail.com>
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
prev parent reply other threads:[~2013-08-24 10:50 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-08-23 0:52 Finding out who's holding a lock? Andy Lutomirski
2013-08-24 10:50 ` Peter Hurley [this message]
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