linux-kernel - Re: [PATCH-tip v2 04/10] locking/rwsem: Micro-optimize rwsem_try_read_lock

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: <20190221141514.GE12696@fuggles.cambridge.arm.com>
Date:   Thu, 21 Feb 2019 14:15:14 +0000
From:   Will Deacon <will.deacon@....com>
To:     Waiman Long <longman@...hat.com>
Cc:     Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        linux-kernel@...r.kernel.org, x86@...nel.org,
        Arnd Bergmann <arnd@...db.de>, Borislav Petkov <bp@...en8.de>,
        "H. Peter Anvin" <hpa@...or.com>,
        Davidlohr Bueso <dave@...olabs.net>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Tim Chen <tim.c.chen@...ux.intel.com>
Subject: Re: [PATCH-tip v2 04/10] locking/rwsem: Micro-optimize
 rwsem_try_read_lock_unqueued()

On Fri, Feb 15, 2019 at 03:50:04PM -0500, Waiman Long wrote:
> The atomic_long_cmpxchg_acquire() in rwsem_try_read_lock_unqueued() is
> replaced by atomic_long_try_cmpxchg_acquire() to simpify the code and
> generate slightly better assembly code. There is no functional change.

Might be nice to illustrate the improvement in the commit message, but
it seems that try_cmpxchg is generally preferred for x86, so:

Acked-by: Will Deacon <will.deacon@....com>

Will