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]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=52189005.30009@hurleysoftware.com \
--to=peter@hurleysoftware.com \
--cc=linux-kernel@vger.kernel.org \
--cc=luto@amacapital.net \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.