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authorMike Travis <travis@sgi.com>2009-01-10 21:58:11 -0800
committerIngo Molnar <mingo@elte.hu>2009-01-11 19:13:25 +0100
commitc7a3589e7a1f8fdbd2536fe1bfa60b37f5121c69 (patch)
treefacf804f00b7de20fd5d79dde7e46c78e3b1ed5c /drivers/xen
parentd38b223c86db3162dc85b5a1997ac8a210e1660b (diff)
Xen: reduce memory required for cpu_evtchn_mask
Impact: reduce memory usage. Reduce this significant gain in the amount of memory used when NR_CPUS bumped from 128 to 4096 by allocating the array based on nr_cpu_ids: 65536 +2031616 2097152 +3100% cpu_evtchn_mask(.bss) Signed-off-by: Mike Travis <travis@sgi.com> Cc: Jeremy Fitzhardinge <jeremy@xensource.com> Cc: Chris Wright <chrisw@sous-sol.org> Cc: virtualization@lists.osdl.org Cc: xen-devel@lists.xensource.com
Diffstat (limited to 'drivers/xen')
-rw-r--r--drivers/xen/events.c21
1 files changed, 16 insertions, 5 deletions
diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index e0767ff35d6c..ed7527b3745a 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -75,7 +75,14 @@ enum {
static int evtchn_to_irq[NR_EVENT_CHANNELS] = {
[0 ... NR_EVENT_CHANNELS-1] = -1
};
-static unsigned long cpu_evtchn_mask[NR_CPUS][NR_EVENT_CHANNELS/BITS_PER_LONG];
+struct cpu_evtchn_s {
+ unsigned long bits[NR_EVENT_CHANNELS/BITS_PER_LONG];
+};
+static struct cpu_evtchn_s *cpu_evtchn_mask_p;
+static inline unsigned long *cpu_evtchn_mask(int cpu)
+{
+ return cpu_evtchn_mask_p[cpu].bits;
+}
static u8 cpu_evtchn[NR_EVENT_CHANNELS];
/* Reference counts for bindings to IRQs. */
@@ -115,7 +122,7 @@ static inline unsigned long active_evtchns(unsigned int cpu,
unsigned int idx)
{
return (sh->evtchn_pending[idx] &
- cpu_evtchn_mask[cpu][idx] &
+ cpu_evtchn_mask(cpu)[idx] &
~sh->evtchn_mask[idx]);
}
@@ -128,8 +135,8 @@ static void bind_evtchn_to_cpu(unsigned int chn, unsigned int cpu)
cpumask_copy(irq_to_desc(irq)->affinity, cpumask_of(cpu));
#endif
- __clear_bit(chn, cpu_evtchn_mask[cpu_evtchn[chn]]);
- __set_bit(chn, cpu_evtchn_mask[cpu]);
+ __clear_bit(chn, cpu_evtchn_mask(cpu_evtchn[chn]));
+ __set_bit(chn, cpu_evtchn_mask(cpu));
cpu_evtchn[chn] = cpu;
}
@@ -147,7 +154,7 @@ static void init_evtchn_cpu_bindings(void)
#endif
memset(cpu_evtchn, 0, sizeof(cpu_evtchn));
- memset(cpu_evtchn_mask[0], ~0, sizeof(cpu_evtchn_mask[0]));
+ memset(cpu_evtchn_mask(0), ~0, sizeof(cpu_evtchn_mask(0)));
}
static inline unsigned int cpu_from_evtchn(unsigned int evtchn)
@@ -822,6 +829,10 @@ static struct irq_chip xen_dynamic_chip __read_mostly = {
void __init xen_init_IRQ(void)
{
int i;
+ size_t size = nr_cpu_ids * sizeof(struct cpu_evtchn_s);
+
+ cpu_evtchn_mask_p = kmalloc(size, GFP_KERNEL);
+ BUG_ON(cpu_evtchn_mask == NULL);
init_evtchn_cpu_bindings();