On 06/07/2012 12:32 PM, Steven Rostedt wrote:
On Thu, 2012-06-07 at 12:08 -0700, David Daney wrote:
Should it go to mainline stable?
I don't think it is necessary. As far as I know, RT may be the only
thing that needs it.
Ah, you're right. As this is just an issue because it is called with
interrupts disabled (from stop_machine). Although it's interesting that
the mips code, re-enables interrupts from that function.
From kernel/cpu.c:
_cpu_down() {
__stop_machine(take_cpu_down,&tcd_param, cpumask_of(cpu));
take_cpu_down() {
err = __cpu_disable();
kernel/stop_machine.c:
__stop_machine(int (*fn)(void *) ...) {
local_irq_save(flags);
hard_irq_disable();
ret = (*fn)(data);
local_irq_restore(flags);
arch/mips/include/asm/smp.h:
static inline int __cpu_disable(void)
{
extern struct plat_smp_ops *mp_ops; /* private */
return mp_ops->cpu_disable();
}
arch/mips/cavium-octeon/smp.c:
octeon_cpu_disable(void) {
local_irq_disable();
fixup_irqs();
local_irq_enable();
struct plat_smp_ops octeon_smp_ops = {
.cpu_disable = octeon_cpu_disable,
Is this expected? It causes the cpu notifiers to be called with
interrupts enabled. Not sure if that's a problem or not.
I am inclined to go with your instinct here. Probably we shouldn't
unconditionally local_irq_enable() here.
Perhaps {,raw}_local_irq_save/{,raw}local_irq_restore would be better.
Or even no local irq enable manipulation...
In any event, I may let Ralf sort it out.
David Daney
--
To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
