linux-kernel - Re: [PATCH RFC 1/3] mutex: Make more scalable by doing less atomic operations

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

Message-ID: <20130410103144.GC28505@gmail.com>
Date:	Wed, 10 Apr 2013 12:31:44 +0200
From:	Ingo Molnar <mingo@...nel.org>
To:	Waiman Long <Waiman.Long@...com>
Cc:	Linus Torvalds <torvalds@...ux-foundation.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>,
	"H. Peter Anvin" <hpa@...or.com>,
	"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>,
	David Howells <dhowells@...hat.com>,
	Dave Jones <davej@...hat.com>,
	Clark Williams <williams@...hat.com>,
	Peter Zijlstra <peterz@...radead.org>,
	Davidlohr Bueso <davidlohr.bueso@...com>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	"Chandramouleeswaran, Aswin" <aswin@...com>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Andrew Morton <akpm@...ux-foundation.org>,
	"Norton, Scott J" <scott.norton@...com>,
	Rik van Riel <riel@...hat.com>
Subject: Re: [PATCH RFC 1/3] mutex: Make more scalable by doing less atomic
 operations


* Waiman Long <Waiman.Long@...com> wrote:

> > That said, the MUTEX_SHOULD_XCHG_COUNT macro should die. Why shouldn't all 
> > architectures just consider negative counts to be locked? It doesn't matter 
> > that some might only ever see -1.
> 
> I think so too. However, I don't have the machines to test out other 
> architectures. The MUTEX_SHOULD_XCHG_COUNT is just a safety measure to make sure 
> that my code won't screw up the kernel in other architectures. Once it is 
> confirmed that a negative count other than -1 is fine for all the other 
> architectures, the macro can certainly go.

I'd suggest to just remove it in an additional patch, Cc:-ing 
linux-arch@...r.kernel.org. The change is very likely to be fine, if not then it's 
easy to revert it.

Thanks,

	Ingo
--
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/