74 lines
2.1 KiB
Diff
74 lines
2.1 KiB
Diff
From 818f63a2fd1445b9723502079135aa8101486de1 Mon Sep 17 00:00:00 2001
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From: Steven Rostedt <rostedt@goodmis.org>
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Date: Thu, 1 Mar 2012 13:55:28 -0500
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Subject: [235/256] timer: Fix hotplug for -rt
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Revert the RT patch:
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Author: Ingo Molnar <mingo@elte.hu>
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Date: Fri Jul 3 08:30:32 2009 -0500
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timers: fix timer hotplug on -rt
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Here we are in the CPU_DEAD notifier, and we must not sleep nor
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enable interrupts.
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There's no problem with sleeping in this notifier.
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But the get_cpu_var() had to be converted to a get_local_var().
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Replace the previous fix with the get_local_var() convert.
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Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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Cc: Carsten Emde <C.Emde@osadl.org>
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Cc: John Kacur <jkacur@redhat.com>
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Cc: Peter Zijlstra <peterz@infradead.org>
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Cc: Clark Williams <clark.williams@gmail.com>
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Cc: stable-rt@vger.kernel.org
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Link: http://lkml.kernel.org/r/20120301190344.948157137@goodmis.org
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Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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---
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kernel/timer.c | 16 +++++-----------
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1 file changed, 5 insertions(+), 11 deletions(-)
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diff --git a/kernel/timer.c b/kernel/timer.c
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index 935f46d..5413ff6 100644
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--- a/kernel/timer.c
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+++ b/kernel/timer.c
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@@ -1793,21 +1793,17 @@ static void __cpuinit migrate_timers(int cpu)
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{
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struct tvec_base *old_base;
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struct tvec_base *new_base;
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- unsigned long flags;
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int i;
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BUG_ON(cpu_online(cpu));
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old_base = per_cpu(tvec_bases, cpu);
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- new_base = get_cpu_var(tvec_bases);
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+ new_base = get_local_var(tvec_bases);
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/*
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* The caller is globally serialized and nobody else
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* takes two locks at once, deadlock is not possible.
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*/
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- local_irq_save(flags);
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- while (!spin_trylock(&new_base->lock))
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- cpu_relax();
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- while (!spin_trylock(&old_base->lock))
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- cpu_relax();
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+ spin_lock_irq(&new_base->lock);
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+ spin_lock_nested(&old_base->lock, SINGLE_DEPTH_NESTING);
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BUG_ON(old_base->running_timer);
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@@ -1821,10 +1817,8 @@ static void __cpuinit migrate_timers(int cpu)
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}
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spin_unlock(&old_base->lock);
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- spin_unlock(&new_base->lock);
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- local_irq_restore(flags);
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-
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- put_cpu_var(tvec_bases);
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+ spin_unlock_irq(&new_base->lock);
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+ put_local_var(tvec_bases);
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}
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#endif /* CONFIG_HOTPLUG_CPU */
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