linux-kernel - Re: [PATCH v2] introduce atomic_pointer to fix a race condition in cancelable mcs spinlocks

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: <538CB68A.6030408@zytor.com>
Date:	Mon, 02 Jun 2014 10:38:18 -0700
From:	"H. Peter Anvin" <hpa@...or.com>
To:	Waiman Long <waiman.long@...com>, Jason Low <jason.low2@...com>
CC:	Mikulas Patocka <mpatocka@...hat.com>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Peter Zijlstra <peterz@...radead.org>, jejb@...isc-linux.org,
	deller@....de, John David Anglin <dave.anglin@...l.net>,
	linux-parisc@...r.kernel.org, linux-kernel@...r.kernel.org,
	paulmck@...ux.vnet.ibm.com, chegu_vinod@...com, tglx@...utronix.de,
	riel@...hat.com, akpm@...ux-foundation.org, davidlohr@...com,
	andi@...stfloor.org, aswin@...com, scott.norton@...com
Subject: Re: [PATCH v2] introduce atomic_pointer to fix a race condition in
 cancelable mcs spinlocks

On 06/02/2014 10:25 AM, Waiman Long wrote:
> 
> Doing an xchg is a very expensive operation compared with ACCESS_ONCE. I
> will not suggest doing that to make it right for PA-RISC at the expense
> of performance in other architectures.
> 

And of course, this gets into the toxic question: what are reasonable
minimum requirements for Linux?  How far do we need to stretch to
support niche architectures which have very small (Linux) userbases?

	-hpa


--
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/