From: Dave Jones <davej@redhat.com>
To: Keith Owens <kaos@ocs.com.au>
Cc: Rusty Russell <rusty@rustcorp.com.au>, linux-kernel@vger.kernel.org
Subject: Re: [DOCUMENTATION] Revised Unreliable Kernel Locking Guide
Date: Fri, 12 Dec 2003 18:25:56 +0000 [thread overview]
Message-ID: <20031212182556.GB10584@redhat.com> (raw)
In-Reply-To: <4939.1071246352@ocs3.intra.ocs.com.au>
On Sat, Dec 13, 2003 at 03:25:52AM +1100, Keith Owens wrote:
> On Fri, 12 Dec 2003 15:44:01 +0000,
> Dave Jones <davej@redhat.com> wrote:
> > Might be worth mentioning in the Per-CPU data section that code doing
> >operations on CPU registers (MSRs and the like) needs to be protected
> >by an explicit preempt_disable() / preempt_enable() pair if it's doing
> >operations that it expects to run on a specific CPU.
>
> Also calls to smp_call_function() need to be wrapped in preempt_disable,
> plus any work that is done on the current cpu before/after calling a
> function on the other cpus. Lack of preempt disable could result in
> the operation being done twice on one cpu and not at all on another.
And where you want to do the same thing on every processor, there's a
handy on_each_cpu() which takes care of this for you.
Dave
next prev parent reply other threads:[~2003-12-12 18:34 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-12-12 5:24 [DOCUMENTATION] Revised Unreliable Kernel Locking Guide Rusty Russell
2003-12-12 15:44 ` Dave Jones
2003-12-12 16:25 ` Keith Owens
2003-12-12 18:25 ` Dave Jones [this message]
2003-12-13 0:28 ` Keith Owens
2003-12-12 21:05 ` Rob Love
2003-12-15 2:28 ` Rusty Russell
2003-12-12 19:35 ` Paul E. McKenney
2003-12-13 3:16 ` Zwane Mwaikambo
2003-12-15 5:17 ` Rusty Russell
2003-12-15 5:17 ` Rusty Russell
2003-12-15 22:22 ` Paul E. McKenney
2003-12-16 6:32 ` Rusty Russell
-- strict thread matches above, loose matches on Subject: below --
2003-12-13 3:15 Manfred Spraul
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