On Mon, 2005-11-21 at 09:21 -0800, Christoph Lameter wrote:
> On Mon, 21 Nov 2005, Pekka J Enberg wrote:
>
> > This patch gets rid of one if-else statement by moving current node allocation
> > check at the beginning of kmem_cache_alloc_node().
>
> The problem with this is that the numa_node may change if irqs are still
> active and your patch moves the check for the numa node outside of the
> section where irqs are enabled.
>
> You could move the check for -1 into the section where interrupts are
> disabled.
So we could do something like the following. Unfortunately it does not
seem much of an improvement... Thoughts?
Pekka
Index: 2.6/mm/slab.c
===================================================================
--- 2.6.orig/mm/slab.c
+++ 2.6/mm/slab.c
@@ -2866,21 +2866,23 @@ void *kmem_cache_alloc_node(kmem_cache_t
unsigned long save_flags;
void *ptr;
- if (nodeid == -1)
- return __cache_alloc(cachep, flags);
+ cache_alloc_debugcheck_before(cachep, flags);
+ local_irq_save(save_flags);
+
+ if (nodeid == -1 || nodeid == numa_node_id()) {
+ ptr = ____cache_alloc(cachep, flags);
+ goto out;
+ }
if (unlikely(!cachep->nodelists[nodeid])) {
/* Fall back to __cache_alloc if we run into trouble */
printk(KERN_WARNING "slab: not allocating in inactive node %d for cache %s\n", nodeid, cachep->name);
- return __cache_alloc(cachep,flags);
+ ptr = ____cache_alloc(cachep,flags);
+ goto out;
}
- cache_alloc_debugcheck_before(cachep, flags);
- local_irq_save(save_flags);
- if (nodeid == numa_node_id())
- ptr = ____cache_alloc(cachep, flags);
- else
- ptr = __cache_alloc_node(cachep, flags, nodeid);
+ ptr = __cache_alloc_node(cachep, flags, nodeid);
+ out:
local_irq_restore(save_flags);
ptr = cache_alloc_debugcheck_after(cachep, flags, ptr, __builtin_return_address(0));
-
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