Messages in this thread | | | Date | Tue, 19 Feb 2013 11:38:32 +0100 | Subject | Re: Debugging Thinkpad T430s occasional suspend failure. | From | Frederic Weisbecker <> |
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2013/2/18 Thomas Gleixner <tglx@linutronix.de>: > On Mon, 18 Feb 2013, Frederic Weisbecker wrote: >> diff --git a/kernel/softirq.c b/kernel/softirq.c >> index ed567ba..69fbefd 100644 >> --- a/kernel/softirq.c >> +++ b/kernel/softirq.c >> @@ -277,6 +277,17 @@ restart: >> tsk_restore_flags(current, old_flags, PF_MEMALLOC); >> } >> >> +#ifndef __ARCH_IRQ_EXIT_IRQS_DISABLED > > We really should get rid of that and make irqs disabled on irq exit > mandatory.
Until now I even thought that having irqs disabled in irq_exit() was mandatory. I need to have a second look at tick_nohz_irq_exit() as I modified it with this requirement in mind...
Also with this patch, if a nesting interrupt happens right after tick_nohz_irq_exit(), this new irq will call tick_nohz_stop_idle() but not tick_nohz_start_idle() on the end. Leaving that unbalanced. I could work that around but I don't want to spaghettize further around that ifdef.
So this patch actually does depend on __ARCH_IRQ_EXIT_IRQS_DISABLED. I need to convert all archs to force this first. Then think about the softirq.c cleanup once its done.
I wonder what's the right path to this, may be loop over archs until they all have __ARCH_IRQ_EXIT_IRQS_DISABLED, then remove that? Sounds like non-sense but the safest way at the same time.
>> @@ -320,20 +331,45 @@ void irq_enter(void) >> __irq_enter(); >> } >> >> +/* >> + * Invoce softirq's from irq_exit(). >> + * >> + * Return the preempt offset: either IRQ_EXIT_OFFSET (if we >> + * did nothing to the preemption count) or SOFTIRQ_OFFSET (in >> + * case we did softirq processing and changed the preemption >> + * count to account for that). >> + */ >> static inline void invoke_softirq(void) >> { >> - if (!force_irqthreads) { >> + /* Can we run softirq's at all? We migth be nesting interrupts */ >> + if (in_nesting_interrupt()) >> + return; > > We might also be in a softirq disabled region where it makes no sense > to continue. So this should be > > in_nesting_interrupt() || in_softirq()
in_nesting_interrupt() takes care of that as well.
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