From mboxrd@z Thu Jan 1 00:00:00 1970 From: Steven Rostedt Subject: [PATCH RT 1/9][RFC] [PATCH 1/9] timer: Fix hotplug for -rt Date: Thu, 01 Mar 2012 13:55:28 -0500 Message-ID: <20120301190344.948157137@goodmis.org> References: <20120301185527.064629423@goodmis.org> Cc: Thomas Gleixner , Carsten Emde , John Kacur , Peter Zijlstra , Clark Williams To: linux-kernel@vger.kernel.org, linux-rt-users Return-path: Content-Disposition: inline; filename=0001-timer-Fix-hotplug-for-rt.patch Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-rt-users.vger.kernel.org Revert the RT patch: Author: Ingo Molnar Date: Fri Jul 3 08:30:32 2009 -0500 timers: fix timer hotplug on -rt Here we are in the CPU_DEAD notifier, and we must not sleep nor enable interrupts. There's no problem with sleeping in this notifier. But the get_cpu_var() had to be converted to a get_local_var(). Replace the previous fix with the get_local_var() convert. Signed-off-by: Steven Rostedt --- kernel/timer.c | 16 +++++----------- 1 files changed, 5 insertions(+), 11 deletions(-) diff --git a/kernel/timer.c b/kernel/timer.c index a791a43..c8c88d1 100644 --- a/kernel/timer.c +++ b/kernel/timer.c @@ -1743,21 +1743,17 @@ static void __cpuinit migrate_timers(int cpu) { struct tvec_base *old_base; struct tvec_base *new_base; - unsigned long flags; int i; BUG_ON(cpu_online(cpu)); old_base = per_cpu(tvec_bases, cpu); - new_base = get_cpu_var(tvec_bases); + new_base = get_local_var(tvec_bases); /* * The caller is globally serialized and nobody else * takes two locks at once, deadlock is not possible. */ - local_irq_save(flags); - while (!spin_trylock(&new_base->lock)) - cpu_relax(); - while (!spin_trylock(&old_base->lock)) - cpu_relax(); + spin_lock_irq(&new_base->lock); + spin_lock_nested(&old_base->lock, SINGLE_DEPTH_NESTING); BUG_ON(old_base->running_timer); @@ -1771,10 +1767,8 @@ static void __cpuinit migrate_timers(int cpu) } spin_unlock(&old_base->lock); - spin_unlock(&new_base->lock); - local_irq_restore(flags); - - put_cpu_var(tvec_bases); + spin_unlock_irq(&new_base->lock); + put_local_var(tvec_bases); } #endif /* CONFIG_HOTPLUG_CPU */ -- 1.7.3.4