36 lines
1.1 KiB
Diff
36 lines
1.1 KiB
Diff
From: Yong Zhang <yong.zhang0@gmail.com>
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Date: Thu, 28 Jul 2011 11:16:00 +0800
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Subject: hotplug: Reread hotplug_pcp on pin_current_cpu() retry
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Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.9/older/patches-4.9-rt1.tar.xz
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When retry happens, it's likely that the task has been migrated to
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another cpu (except unplug failed), but it still derefernces the
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original hotplug_pcp per cpu data.
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Update the pointer to hotplug_pcp in the retry path, so it points to
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the current cpu.
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Signed-off-by: Yong Zhang <yong.zhang0@gmail.com>
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Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
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Link: http://lkml.kernel.org/r/20110728031600.GA338@windriver.com
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Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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---
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kernel/cpu.c | 4 +++-
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1 file changed, 3 insertions(+), 1 deletion(-)
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--- a/kernel/cpu.c
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+++ b/kernel/cpu.c
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@@ -257,9 +257,11 @@ static DEFINE_PER_CPU(struct hotplug_pcp
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*/
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void pin_current_cpu(void)
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{
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- struct hotplug_pcp *hp = this_cpu_ptr(&hotplug_pcp);
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+ struct hotplug_pcp *hp;
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retry:
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+ hp = this_cpu_ptr(&hotplug_pcp);
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+
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if (!hp->unplug || hp->refcount || preempt_count() > 1 ||
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hp->unplug == current) {
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hp->refcount++;
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