From: Ingo Molnar <mingo@elte.hu>
To: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] perf_counter: powerpc: add nmi_enter/nmi_exit calls
Date: Thu, 9 Apr 2009 07:20:02 +0200 [thread overview]
Message-ID: <20090409052002.GE5352@elte.hu> (raw)
In-Reply-To: <18909.31952.873098.336615@cargo.ozlabs.ibm.com>
* Paul Mackerras <paulus@samba.org> wrote:
> Impact: powerpc bug fix
>
> Now that the core is using in_nmi() (added in e30e08f6,
> "perf_counter: fix NMI race in task clock"), we need the powerpc
> perf_counter_interrupt to call nmi_enter() and nmi_exit() in those
> cases where the interrupt happens when interrupts are
> soft-disabled. If interrupts were soft-enabled, we can treat it
> as a regular interrupt and do irq_enter/irq_exit around the whole
> routine. This lets us get rid of the test_perf_counter_pending()
> call at the end of perf_counter_interrupt, thus simplifying things
> a little.
applied, thanks Paul!
I'm wondering, what was the real impact? Was it a crash or some
other misbehavior? This impact line:
Impact: powerpc bug fix
is a bit too generic to be useful in practice. Something like:
Impact: fix stuck NMIs on powerpc
Impact: fix NMI crash on powerpc
would have been more descriptive about the real, hands-on impact of
this patch.
Ingo
next prev parent reply other threads:[~2009-04-09 5:20 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-04-09 4:42 Paul Mackerras
2009-04-09 5:20 ` Ingo Molnar [this message]
2009-04-09 5:49 ` Paul Mackerras
2009-04-09 6:05 ` Ingo Molnar
2009-04-09 5:30 ` [tip:perfcounters/core] " Paul Mackerras
2009-04-09 5:57 ` Paul Mackerras
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