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sparse irq_desc[] array: core kernel and x86 changes

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Impact: new feature

Problem on distro kernels: irq_desc[NR_IRQS] takes megabytes of RAM with
NR_CPUS set to large values. The goal is to be able to scale up to much
larger NR_IRQS value without impacting the (important) common case.

To solve this, we generalize irq_desc[NR_IRQS] to an (optional) array of
irq_desc pointers.

When CONFIG_SPARSE_IRQ=y is used, we use kzalloc_node to get irq_desc,
this also makes the IRQ descriptors NUMA-local (to the site that calls
request_irq()).

This gets rid of the irq_cfg[] static array on x86 as well: irq_cfg now
uses desc->chip_data for x86 to store irq_cfg.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Yinghai Lu
2008-12-05 18:58:31 -08:00
committed by Ingo Molnar
parent 218d11a8b0
commit 0b8f1efad3
23 changed files with 659 additions and 173 deletions
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12
drivers/xen/events.c
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@@ -141,8 +141,12 @@ static void init_evtchn_cpu_bindings(void)
int i;
/* By default all event channels notify CPU#0. */
for_each_irq_desc(i, desc)
for_each_irq_desc(i, desc) {
if (!desc)
continue;
desc->affinity = cpumask_of_cpu(0);
}
#endif
memset(cpu_evtchn, 0, sizeof(cpu_evtchn));
@@ -231,7 +235,7 @@ static int find_unbound_irq(void)
int irq;
/* Only allocate from dynirq range */
for_each_irq_nr(irq)
for (irq = 0; irq < nr_irqs; irq++)
if (irq_bindcount[irq] == 0)
break;
@@ -792,7 +796,7 @@ void xen_irq_resume(void)
mask_evtchn(evtchn);
/* No IRQ <-> event-channel mappings. */
for_each_irq_nr(irq)
for (irq = 0; irq < nr_irqs; irq++)
irq_info[irq].evtchn = 0; /* zap event-channel binding */
for (evtchn = 0; evtchn < NR_EVENT_CHANNELS; evtchn++)
@@ -824,7 +828,7 @@ void __init xen_init_IRQ(void)
mask_evtchn(i);
/* Dynamic IRQ space is currently unbound. Zero the refcnts. */
for_each_irq_nr(i)
for (i = 0; i < nr_irqs; i++)
irq_bindcount[i] = 0;
irq_ctx_init(smp_processor_id());