2006-09-29 12:06:13

by Pekka Enberg

Subject: [PATCH] slab: reduce numa text size

From: Pekka Enberg <[email protected]>

This patch reduces NUMA text size of mm/slab.o a little on x86 by using
a local variable to store the result of numa_node_id().

text data bss dec hex filename
16858 2584 16 19458 4c02 mm/slab.o (before)
16804 2584 16 19404 4bcc mm/slab.o (after)

Cc: Christoph Lameter <[email protected]>
Signed-off-by: Pekka Enberg <[email protected]>
---

diff --git a/mm/slab.c b/mm/slab.c
index 792bfe3..baf8355 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -1107,15 +1107,18 @@ static inline int cache_free_alien(struc
int nodeid = slabp->nodeid;
struct kmem_list3 *l3;
struct array_cache *alien = NULL;
+ int this_node;
+
+ this_node = numa_node_id();

/*
* Make sure we are not freeing a object from another node to the array
* cache on this cpu.
*/
- if (likely(slabp->nodeid == numa_node_id()))
+ if (likely(slabp->nodeid == this_node))
return 0;

- l3 = cachep->nodelists[numa_node_id()];
+ l3 = cachep->nodelists[this_node];
STATS_INC_NODEFREES(cachep);
if (l3->alien && l3->alien[nodeid]) {
alien = l3->alien[nodeid];
@@ -1353,6 +1356,7 @@ void __init kmem_cache_init(void)
struct cache_names *names;
int i;
int order;
+ int this_node;

for (i = 0; i < NUM_INIT_LISTS; i++) {
kmem_list3_init(&initkmem_list3[i]);
@@ -1387,12 +1391,14 @@ void __init kmem_cache_init(void)
* 6) Resize the head arrays of the kmalloc caches to their final sizes.
*/

+ this_node = numa_node_id();
+
/* 1) create the cache_cache */
INIT_LIST_HEAD(&cache_chain);
list_add(&cache_cache.next, &cache_chain);
cache_cache.colour_off = cache_line_size();
cache_cache.array[smp_processor_id()] = &initarray_cache.cache;
- cache_cache.nodelists[numa_node_id()] = &initkmem_list3[CACHE_CACHE];
+ cache_cache.nodelists[this_node] = &initkmem_list3[CACHE_CACHE];

cache_cache.buffer_size = ALIGN(cache_cache.buffer_size,
cache_line_size());
@@ -1500,7 +1506,7 @@ void __init kmem_cache_init(void)
int node;
/* Replace the static kmem_list3 structures for the boot cpu */
init_list(&cache_cache, &initkmem_list3[CACHE_CACHE],
- numa_node_id());
+ this_node);

for_each_online_node(node) {
init_list(malloc_sizes[INDEX_AC].cs_cachep,
@@ -2897,6 +2903,9 @@ static void *cache_alloc_refill(struct k
int batchcount;
struct kmem_list3 *l3;
struct array_cache *ac;
+ int this_node;
+
+ this_node = numa_node_id();

check_irq_off();
ac = cpu_cache_get(cachep);
@@ -2910,7 +2919,7 @@ retry:
*/
batchcount = BATCHREFILL_LIMIT;
}
- l3 = cachep->nodelists[numa_node_id()];
+ l3 = cachep->nodelists[this_node];

BUG_ON(ac->avail > 0 || !l3);
spin_lock(&l3->list_lock);
@@ -2940,7 +2949,7 @@ retry:
STATS_SET_HIGH(cachep);

ac->entry[ac->avail++] = slab_get_obj(cachep, slabp,
- numa_node_id());
+ this_node);
}
check_slabp(cachep, slabp);

@@ -2959,7 +2968,7 @@ alloc_done:

if (unlikely(!ac->avail)) {
int x;
- x = cache_grow(cachep, flags, numa_node_id());
+ x = cache_grow(cachep, flags, this_node);

/* cache_grow can reenable interrupts, then ac could change. */
ac = cpu_cache_get(cachep);

2006-09-29 15:58:09

by Christoph Lameter

Subject: Re: [PATCH] slab: reduce numa text size

On Fri, 29 Sep 2006, Pekka J Enberg wrote:

> This patch reduces NUMA text size of mm/slab.o a little on x86 by using
> a local variable to store the result of numa_node_id().

Looks okay.

The convention for this local variable is to use simply "node"
not "thisnode". See other optimizations like that in the slab
allocator.