Messages in this thread Patch in this message | | | Date | Fri, 17 Mar 2006 15:26:45 -0800 | From | Andrew Morton <> | Subject | Re: [PATCH] Add SA_PERCPU_IRQ flag support |
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Dimitri Sivanich <sivanich@sgi.com> wrote: > > he generic request_irq/setup_irq code should support the SA_PERCPU_IRQ flag. > > Not sure why it was left out, but this patch adds that support. > > Signed-off-by: Dimitri Sivanich <sivanich@sgi.com> > > Index: linux/kernel/irq/manage.c > =================================================================== > --- linux.orig/kernel/irq/manage.c 2006-03-16 14:05:27.957927445 -0600 > +++ linux/kernel/irq/manage.c 2006-03-16 14:06:02.283661867 -0600 > @@ -201,6 +201,9 @@ int setup_irq(unsigned int irq, struct i > * The following block of code has to be executed atomically > */ > spin_lock_irqsave(&desc->lock,flags); > + if (new->flags & SA_PERCPU_IRQ) { > + desc->status |= IRQ_PER_CPU; > + } > p = &desc->action; > if ((old = *p) != NULL) { > /* Can't share interrupts unless both agree to */
Yes, we're presently going in and needlessly taking desc->lock on every cpu-local interrupt. However it only appears to affect mmtimer.c at present.
Shouldn't we also have a check in there, to make sure that all the other handlers off this IRQ agree about the per-cpuness of this interrupt?
Your patch broke the x86 build, btw..
From: Dimitri Sivanich <sivanich@sgi.com>
The generic request_irq/setup_irq code should support the SA_PERCPU_IRQ flag.
Also, check that all handlers agree to do per-cpu IRQs.
Signed-off-by: Dimitri Sivanich <sivanich@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> ---
kernel/irq/manage.c | 23 +++++++++++++++++++---- 1 files changed, 19 insertions(+), 4 deletions(-)
diff -puN kernel/irq/manage.c~generic-irq-add-sa_percpu_irq-flag-support kernel/irq/manage.c --- 25/kernel/irq/manage.c~generic-irq-add-sa_percpu_irq-flag-support Fri Mar 17 15:06:44 2006 +++ 25-akpm/kernel/irq/manage.c Fri Mar 17 15:23:02 2006 @@ -204,10 +204,14 @@ int setup_irq(unsigned int irq, struct i p = &desc->action; if ((old = *p) != NULL) { /* Can't share interrupts unless both agree to */ - if (!(old->flags & new->flags & SA_SHIRQ)) { - spin_unlock_irqrestore(&desc->lock,flags); - return -EBUSY; - } + if (!(old->flags & new->flags & SA_SHIRQ)) + goto mismatch; + +#ifdef ARCH_HAS_IRQ_PER_CPU + /* All handlers must agree on per-cpuness */ + if ((old->flags & IRQ_PER_CPU) != (new->flags & IRQ_PER_CPU)) + goto mismatch; +#endif /* add new interrupt at end of irq queue */ do { @@ -219,6 +223,11 @@ int setup_irq(unsigned int irq, struct i *p = new; +#ifdef ARCH_HAS_IRQ_PER_CPU + if (new->flags & SA_PERCPU_IRQ) + desc->status |= IRQ_PER_CPU; +#endif + if (!shared) { desc->depth = 0; desc->status &= ~(IRQ_DISABLED | IRQ_AUTODETECT | @@ -236,6 +245,12 @@ int setup_irq(unsigned int irq, struct i register_handler_proc(irq, new); return 0; + +mismatch: + spin_unlock_irqrestore(&desc->lock, flags); + printk(KERN_ERR "%s: irq handler mismatch\n", __FUNCTION__); + dump_stack(); + return -EBUSY; } #ifdef CONFIG_DEBUG_SHIRQ _ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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