From: Andi Kleen <andi@firstfloor.org>
To: Gregory Haskins <ghaskins@novell.com>
Cc: mingo@elte.hu, rostedt@goodmis.org, tglx@linutronix.de,
linux-kernel@vger.kernel.org, linux-rt-users@vger.kernel.org,
gregory.haskins@gmail.com
Subject: Re: [PATCH] seqlock: serialize against writers
Date: Fri, 29 Aug 2008 18:09:16 +0200 [thread overview]
Message-ID: <87abevpzv7.fsf@basil.nowhere.org> (raw)
In-Reply-To: <20080829154237.1196.66825.stgit@dev.haskins.net> (Gregory Haskins's message of "Fri, 29 Aug 2008 11:44:58 -0400")
Gregory Haskins <ghaskins@novell.com> writes:
> *Patch submitted for inclusion in PREEMPT_RT 26-rt4. Applies to 2.6.26.3-rt3*
>
> Hi Ingo, Steven, Thomas,
> Please consider for -rt4. This fixes a nasty deadlock on my systems under
> heavy load.
Does this even work under x86-64? x86-64 uses seqlocks in user space
in its vsyscalls. And read_lock() definitely doesn't work there because
it writes.
You would need at least to disable vsyscall gettimeofday(), making
it much much slower.
Perhaps you tested on one of the systems where the vsyscalls need
to fallback for other reasons? (e.g. one using pmtimer for timing).
-Andi
next prev parent reply other threads:[~2008-08-29 16:09 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-08-29 15:44 [PATCH] seqlock: serialize against writers Gregory Haskins
2008-08-29 16:09 ` Andi Kleen [this message]
2008-08-29 16:10 ` Gregory Haskins
2008-08-29 16:22 ` Andi Kleen
2008-08-29 16:26 ` Gregory Haskins
2008-08-29 16:34 ` Steven Rostedt
2008-08-29 16:35 ` Gregory Haskins
2008-08-29 16:45 ` Andi Kleen
2008-08-29 16:53 ` Steven Rostedt
2008-08-29 17:00 ` Gregory Haskins
2008-08-29 17:00 ` Gregory Haskins
2008-08-29 16:58 ` Steven Rostedt
2008-08-29 16:29 ` Gregory Haskins
2008-08-29 16:37 ` Andi Kleen
2008-08-29 16:41 ` Gregory Haskins
2008-08-29 17:08 ` Andi Kleen
2008-08-29 16:57 ` Stephen Hemminger
2008-08-29 17:02 ` [ RT PATCH] " Steven Rostedt
2008-08-29 18:03 ` [RT PATCH v2] " Gregory Haskins
2008-08-29 18:12 ` Gregory Haskins
2008-08-30 11:17 ` Peter Zijlstra
2008-08-30 12:32 ` Gregory Haskins
2008-08-30 12:38 ` Peter Zijlstra
2008-08-30 13:05 ` Gregory Haskins
2008-08-30 11:08 ` [PATCH] " Peter Zijlstra
2008-09-02 12:45 ` [RT PATCH v3] " Gregory Haskins
2008-09-02 13:01 ` Gregory Haskins
2008-09-02 13:29 ` [RT PATCH v4] " Gregory Haskins
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=87abevpzv7.fsf@basil.nowhere.org \
--to=andi@firstfloor.org \
--cc=ghaskins@novell.com \
--cc=gregory.haskins@gmail.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-rt-users@vger.kernel.org \
--cc=mingo@elte.hu \
--cc=rostedt@goodmis.org \
--cc=tglx@linutronix.de \
/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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox