From: "H. Peter Anvin" <hpa@zytor.com>
To: Cliff Wickman <cpw@sgi.com>
Cc: Ingo Molnar <mingo@elte.hu>,
linux-kernel@vger.kernel.org,
Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH 1 of 6] x86, UV: smp_processor_id in a preemptable region
Date: Wed, 15 Jun 2011 10:21:42 -0700 [thread overview]
Message-ID: <4DF8EA26.2000301@zytor.com> (raw)
In-Reply-To: <20110615164027.GA32641@sgi.com>
On 06/15/2011 09:40 AM, Cliff Wickman wrote:
>
> So would you say I should really widen the scope of the non-preemptible
> region to include everything done with the results of that call to
> smp_processor_id()?
> Which in this case is the call to parse_tunables_write().
> Like this:
>
> preempt_disable();
> bcp = &per_cpu(bau_control, smp_processor_id());
>
> ret = parse_tunables_write(bcp, instr, count);
> preempt_enable_no_resched();
>
Funny enough, this is such a common pattern that we have helpers for it.
We call this get_cpu() ... put_cpu().
-hpa
next prev parent reply other threads:[~2011-06-15 17:22 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-06-14 23:06 [PATCH 1 of 6] x86, UV: smp_processor_id in a preemptable region Cliff Wickman
2011-06-15 6:05 ` Rakib Mullick
2011-06-15 13:52 ` Cliff Wickman
2011-06-15 15:54 ` Ingo Molnar
2011-06-15 16:07 ` Cliff Wickman
2011-06-15 16:15 ` Ingo Molnar
2011-06-15 16:40 ` Cliff Wickman
2011-06-15 17:21 ` H. Peter Anvin [this message]
2011-06-15 18:58 ` Cliff Wickman
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