linux-kernel - Re: [PATCH v2 0/7] locking/rwsem: enable reader opt-spinning & writer respin

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: <1407455524.2513.10.camel@buesod1.americas.hpqcorp.net>
Date:	Thu, 07 Aug 2014 16:52:04 -0700
From:	Davidlohr Bueso <davidlohr@...com>
To:	Waiman Long <Waiman.Long@...com>
Cc:	Ingo Molnar <mingo@...nel.org>,
	Peter Zijlstra <peterz@...radead.org>,
	linux-kernel@...r.kernel.org, Jason Low <jason.low2@...com>,
	Scott J Norton <scott.norton@...com>
Subject: Re: [PATCH v2 0/7] locking/rwsem: enable reader opt-spinning &
 writer respin

On Thu, 2014-08-07 at 18:26 -0400, Waiman Long wrote:
> v1->v2:
>  - Remove patch 1 which changes preempt_enable() to
>    preempt_enable_no_resched().
>  - Remove the RWSEM_READ_OWNED macro and assume readers own the lock
>    when owner is NULL.
>  - Reduce the spin threshold to 64.

So I still don't like this, and the fact that it is used in some
virtualization locking bits doesn't really address the concerns about
arbitrary logic in our general locking code.

Also, why did you reduce it from 100 to 64? This very much wants to be
commented.

Thanks,
Davidlohr

--
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/