Before when we were setting up the irq host map for mpic we passed in
just isu_size for the size of the linear map. However, for a number of
mpic implementations we have no isu (thus pass in 0) and will end up
with a no linear map (size = 0). This causes us to always call
irq_find_mapping() from mpic_get_irq().
By moving the allocation of the host map to after we've determined the
number of sources we can actually benefit from having a linear map for
the non-isu users that covers all the interrupt sources.
Signed-off-by: Kumar Gala <ga...@kernel.crashing.org>
---
Ben,
I leave it up to you if you want to put this in for 2.6.30. We see about a 1us
reduction in time spent in mpic_get_irq() based on ftrace.
- k
arch/powerpc/sysdev/mpic.c | 16 +++++++++-------
1 files changed, 9 insertions(+), 7 deletions(-)
diff --git a/arch/powerpc/sysdev/mpic.c b/arch/powerpc/sysdev/mpic.c
index 21b9567..0efc12d 100644
--- a/arch/powerpc/sysdev/mpic.c
+++ b/arch/powerpc/sysdev/mpic.c
@@ -1057,13 +1057,6 @@ struct mpic * __init mpic_alloc(struct device_node *node,
memset(mpic, 0, sizeof(struct mpic));
mpic->name = name;
- mpic->irqhost = irq_alloc_host(node, IRQ_HOST_MAP_LINEAR,
- isu_size, &mpic_host_ops,
- flags & MPIC_LARGE_VECTORS ? 2048 : 256);
- if (mpic->irqhost == NULL)
- return NULL;
-
- mpic->irqhost->host_data = mpic;
mpic->hc_irq = mpic_irq_chip;
mpic->hc_irq.typename = name;
if (flags & MPIC_PRIMARY)
@@ -1213,6 +1206,15 @@ struct mpic * __init mpic_alloc(struct device_node *node,
mpic->isu_shift = 1 + __ilog2(mpic->isu_size - 1);
mpic->isu_mask = (1 << mpic->isu_shift) - 1;
+ mpic->irqhost = irq_alloc_host(node, IRQ_HOST_MAP_LINEAR,
+ isu_size ? isu_size : mpic->num_sources,
+ &mpic_host_ops,
+ flags & MPIC_LARGE_VECTORS ? 2048 : 256);
+ if (mpic->irqhost == NULL)
+ return NULL;
+
+ mpic->irqhost->host_data = mpic;
+
/* Display version */
switch (greg_feature & MPIC_GREG_FEATURE_VERSION_MASK) {
case 1:
--
1.6.0.6
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