linux-kernel - Re: [PATCH v7 1/4] spinlock: A new lockref structure for lockless update of refcount

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: <52264E10.9050105@hp.com>
Date:	Tue, 03 Sep 2013 17:01:04 -0400
From:	Waiman Long <waiman.long@...com>
To:	Linus Torvalds <torvalds@...ux-foundation.org>
CC:	Ingo Molnar <mingo@...nel.org>, Al Viro <viro@...iv.linux.org.uk>,
	Benjamin Herrenschmidt <benh@...nel.crashing.org>,
	Jeff Layton <jlayton@...hat.com>,
	Miklos Szeredi <mszeredi@...e.cz>,
	Ingo Molnar <mingo@...hat.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	linux-fsdevel <linux-fsdevel@...r.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Peter Zijlstra <peterz@...radead.org>,
	Steven Rostedt <rostedt@...dmis.org>,
	Andi Kleen <andi@...stfloor.org>,
	"Chandramouleeswaran, Aswin" <aswin@...com>,
	"Norton, Scott J" <scott.norton@...com>
Subject: Re: [PATCH v7 1/4] spinlock: A new lockref structure for lockless
 update of refcount

On 09/03/2013 03:09 PM, Linus Torvalds wrote:
> On Tue, Sep 3, 2013 at 8:34 AM, Linus Torvalds
> <torvalds@...ux-foundation.org>  wrote:
>> I suspect the tty_ldisc_lock() could be made to go away if we care.
> Heh. I just pulled the tty patches from Greg, and the locking has
> changed completely.
>
> It may actually fix your AIM7 test-case, because while the global
> spinlock remains (it got renamed to "tty_ldiscs_lock" - there's an
> added "s"), the common operations now take the per-tty lock to get the
> ldisc for that tty, rather than that global spinlock (which just
> protects the actual ldisk array now).
>
> That said, I don't know what AIM7 really ends up doing, but your
> profile seems to have every access through tty_ldisc_[de]ref() that
> now uses only the per-tty lock. Of course, how much that helps ends up
> depending on whether AIM7 uses lots of tty's or just one shared one.
>
> Anyway, it might be worth testing my current -git tree.
>
>                    Linus

Thank for the news. I will fetch your latest git tree and try it out.

-Longman
--
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/