Messages in this thread Patch in this message | | | Date | Mon, 09 Jul 2012 15:31:44 +0100 | From | Ben Hutchings <> | Subject | [ 28/48] ARM: fix rcu stalls on SMP platforms |
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3.2-stable review patch. If anyone has any objections, please let me know.
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From: Russell King <rmk+kernel@arm.linux.org.uk>
commit 7deabca0acfe02b8e18f59a4c95676012f49a304 upstream.
We can stall RCU processing on SMP platforms if a CPU sits in its idle loop for a long time. This happens because we don't call irq_enter() and irq_exit() around generic_smp_call_function_interrupt() and friends. Add the necessary calls, and remove the one from within ipi_timer(), so that they're all in a common place.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> --- arch/arm/kernel/smp.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c index 57db122..26cdc49 100644 --- a/arch/arm/kernel/smp.c +++ b/arch/arm/kernel/smp.c @@ -443,9 +443,7 @@ static DEFINE_PER_CPU(struct clock_event_device, percpu_clockevent); static void ipi_timer(void) { struct clock_event_device *evt = &__get_cpu_var(percpu_clockevent); - irq_enter(); evt->event_handler(evt); - irq_exit(); } #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST @@ -548,7 +546,9 @@ void handle_IPI(int ipinr, struct pt_regs *regs) switch (ipinr) { case IPI_TIMER: + irq_enter(); ipi_timer(); + irq_exit(); break; case IPI_RESCHEDULE: @@ -556,15 +556,21 @@ void handle_IPI(int ipinr, struct pt_regs *regs) break; case IPI_CALL_FUNC: + irq_enter(); generic_smp_call_function_interrupt(); + irq_exit(); break; case IPI_CALL_FUNC_SINGLE: + irq_enter(); generic_smp_call_function_single_interrupt(); + irq_exit(); break; case IPI_CPU_STOP: + irq_enter(); ipi_cpu_stop(cpu); + irq_exit(); break; default:
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