From: Nicolas Pitre <nico@cam.org>
To: Ingo Molnar <mingo@elte.hu>
Cc: Arjan van de Ven <arjan@infradead.org>,
lkml <linux-kernel@vger.kernel.org>
Subject: Re: [patch 1/3] mutex subsystem: trylock
Date: Thu, 29 Dec 2005 11:46:25 -0500 (EST) [thread overview]
Message-ID: <Pine.LNX.4.64.0512291142510.3309@localhost.localdomain> (raw)
In-Reply-To: <20051229083333.GA31003@elte.hu>
On Thu, 29 Dec 2005, Ingo Molnar wrote:
> > I'd solve it like this instead (on top of your latest patches):
>
> thanks, applied.
>
> > + "1: ldrex %0, [%3] \n"
> > + "subs %1, %0, #1 \n"
> > + "strexeq %2, %1, [%3] \n"
> > + "movlt %0, #0 \n"
> > + "cmpeq %2, #0 \n"
> > + "bgt 1b \n"
>
> so we are back to what is in essence a cmpxchg implementation?
A limited cmpxchg. Using the generic cmpxchg for this would need either
9 or 10 instructions instead of 6.
Nicolas
next prev parent reply other threads:[~2005-12-29 16:46 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-12-23 16:16 [patch 00/11] mutex subsystem, -V7 Ingo Molnar
2005-12-24 5:15 ` Nicolas Pitre
2005-12-24 5:23 ` Nicolas Pitre
2005-12-26 19:24 ` Nicolas Pitre
2005-12-26 19:25 ` [patch 1/3] mutex subsystem: trylock Nicolas Pitre
2005-12-27 11:51 ` Ingo Molnar
2005-12-27 20:47 ` Nicolas Pitre
2005-12-28 7:48 ` Ingo Molnar
2005-12-28 8:13 ` Ingo Molnar
2005-12-28 16:29 ` Nicolas Pitre
2005-12-28 17:09 ` Ingo Molnar
2005-12-27 12:05 ` Arjan van de Ven
2005-12-27 13:15 ` Ingo Molnar
2005-12-29 4:06 ` Nicolas Pitre
2005-12-29 8:33 ` Ingo Molnar
2005-12-29 9:01 ` Nick Piggin
2005-12-29 17:15 ` Nicolas Pitre
2005-12-30 2:05 ` Nick Piggin
2005-12-29 16:46 ` Nicolas Pitre [this message]
2005-12-29 3:22 ` Nicolas Pitre
2005-12-26 19:25 ` [patch 2/3] mutex subsystem: fastpath inlining Nicolas Pitre
2005-12-27 11:55 ` Ingo Molnar
2005-12-27 21:59 ` Nicolas Pitre
2005-12-28 7:41 ` Ingo Molnar
2005-12-29 2:53 ` Nicolas Pitre
2005-12-29 8:41 ` Ingo Molnar
2006-01-06 21:20 ` Nicolas Pitre
2005-12-26 19:26 ` [patch 3/3] mutex subsystem: inline mutex_is_locked() Nicolas Pitre
2005-12-27 11:37 ` Ingo Molnar
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=Pine.LNX.4.64.0512291142510.3309@localhost.localdomain \
--to=nico@cam.org \
--cc=arjan@infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@elte.hu \
/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
all inboxes | Powered by JetHome®