[ 28/48] ARM: fix rcu stalls on SMP platforms
From: Ben Hutchings <hidden>
Date: 2012-07-09 14:38:24
Also in:
lkml
Subsystem:
arm port, the rest · Maintainers:
Russell King, Linus Torvalds
3.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: Russell King <redacted> 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 <redacted> Signed-off-by: Ben Hutchings <redacted> --- 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: