59 lines
1.6 KiB
Diff
59 lines
1.6 KiB
Diff
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From 515dbfcc0ada82f09c173da496b20b9c1bc58d40 Mon Sep 17 00:00:00 2001
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From: Tiejun Chen <tiejun.chen@windriver.com>
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Date: Thu, 7 Nov 2013 10:06:07 +0800
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Subject: [PATCH 282/365] cpu_down: move migrate_enable() back
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Commit 08c1ab68, "hotplug-use-migrate-disable.patch", intends to
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use migrate_enable()/migrate_disable() to replace that combination
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of preempt_enable() and preempt_disable(), but actually in
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!CONFIG_PREEMPT_RT_FULL case, migrate_enable()/migrate_disable()
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are still equal to preempt_enable()/preempt_disable(). So that
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followed cpu_hotplug_begin()/cpu_unplug_begin(cpu) would go schedule()
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to trigger schedule_debug() like this:
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_cpu_down()
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+ migrate_disable() = preempt_disable()
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+ cpu_hotplug_begin() or cpu_unplug_begin()
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+ schedule()
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+ __schedule()
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+ preempt_disable();
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+ __schedule_bug() is true!
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So we should move migrate_enable() as the original scheme.
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Signed-off-by: Tiejun Chen <tiejun.chen@windriver.com>
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---
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kernel/cpu.c | 2 +-
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1 file changed, 1 insertion(+), 1 deletion(-)
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diff --git a/kernel/cpu.c b/kernel/cpu.c
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index 072e296c1c12..f4bb4e76e13f 100644
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--- a/kernel/cpu.c
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+++ b/kernel/cpu.c
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@@ -1337,6 +1337,7 @@ static int __ref _cpu_down(unsigned int cpu, int tasks_frozen,
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goto restore_cpus;
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}
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+ migrate_enable();
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cpu_hotplug_begin();
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ret = cpu_unplug_begin(cpu);
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if (ret) {
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@@ -1384,7 +1385,6 @@ static int __ref _cpu_down(unsigned int cpu, int tasks_frozen,
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cpu_unplug_done(cpu);
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out_cancel:
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cpu_hotplug_done();
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- migrate_enable();
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/* This post dead nonsense must die */
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if (!ret && hasdied)
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cpu_notify_nofail(CPU_POST_DEAD, cpu);
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--
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2.28.0
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