linux-kernel - Re: [PATCH v4 1/5] rwsem: check the lock before cpmxchg in down_write

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <1372348758.22432.153.camel@schen9-DESK>
Date:	Thu, 27 Jun 2013 08:59:18 -0700
From:	Tim Chen <tim.c.chen@...ux.intel.com>
To:	Alex Shi <alex.shi@...el.com>
Cc:	Ingo Molnar <mingo@...e.hu>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Andrea Arcangeli <aarcange@...hat.com>,
	Andi Kleen <andi@...stfloor.org>,
	Michel Lespinasse <walken@...gle.com>,
	Davidlohr Bueso <davidlohr.bueso@...com>,
	Matthew R Wilcox <matthew.r.wilcox@...el.com>,
	Dave Hansen <dave.hansen@...el.com>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Rik van Riel <riel@...hat.com>,
	Peter Hurley <peter@...leysoftware.com>,
	linux-kernel@...r.kernel.org, linux-mm <linux-mm@...ck.org>
Subject: Re: [PATCH v4 1/5] rwsem: check the lock before cpmxchg in
 down_write_trylock

On Thu, 2013-06-27 at 09:32 +0800, Alex Shi wrote:
> The following line should be added head of commit log on patches 1~4. :)
> 
> From: Alex Shi <alex.shi@...el.com>
> 
> 
> > Cmpxchg will cause the cacheline bouning when do the value checking,
> > that cause scalability issue in a large machine (like a 80 core box).
> > 
> > So a lock pre-read can relief this contention.
> > 
> > Signed-off-by: Alex Shi <alex.shi@...el.com>
> 
> 

Okay.  Will add the From line in addition to Signed off line on next
update.

Tim

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/