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authorYinghai Lu <yinghai@kernel.org>2008-12-06 03:58:31 +0100
committerIngo Molnar <mingo@elte.hu>2008-12-08 14:31:51 +0100
commit0b8f1efad30bd58f89961b82dfe68b9edf8fd2ac (patch)
tree239251bad791fd60af8c0f2ba365b7188395c83f /drivers/xen/events.c
parentFix a race condition in FASYNC handling (diff)
downloadlinux-0b8f1efad30bd58f89961b82dfe68b9edf8fd2ac.tar.xz
linux-0b8f1efad30bd58f89961b82dfe68b9edf8fd2ac.zip
sparse irq_desc[] array: core kernel and x86 changes
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>
Diffstat (limited to 'drivers/xen/events.c')
-rw-r--r--drivers/xen/events.c12
1 files changed, 8 insertions, 4 deletions
diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index 1e3b934a4cf7..2924faa7f6c4 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -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());