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| author | Eric Dumazet <dada1@cosmosbay.com> | 2007-05-06 23:49:29 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-05-07 21:12:53 +0200 |
| commit | 8da3430d8a7f885c2bf65121181d76c9d290a86e (patch) | |
| tree | 7c5b181f1aaafba569f8c8b7de9cded5dfa9164c | |
| parent | SLAB: don't allocate empty shared caches (diff) | |
| download | linux-8da3430d8a7f885c2bf65121181d76c9d290a86e.tar.xz linux-8da3430d8a7f885c2bf65121181d76c9d290a86e.zip | |
slab: NUMA kmem_cache diet
Some NUMA machines have a big MAX_NUMNODES (possibly 1024), but fewer
possible nodes. This patch dynamically sizes the 'struct kmem_cache' to
allocate only needed space.
I moved nodelists[] field at the end of struct kmem_cache, and use the
following computation in kmem_cache_init()
cache_cache.buffer_size = offsetof(struct kmem_cache, nodelists) +
nr_node_ids * sizeof(struct kmem_list3 *);
On my two nodes x86_64 machine, kmem_cache.obj_size is now 192 instead of 704
(This is because on x86_64, MAX_NUMNODES is 64)
On bigger NUMA setups, this might reduce the gfporder of "cache_cache"
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Andy Whitcroft <apw@shadowen.org>
Cc: Christoph Lameter <clameter@engr.sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | mm/slab.c | 24 |
1 files changed, 20 insertions, 4 deletions
diff --git a/mm/slab.c b/mm/slab.c index 00f98b9f6df1..1f2627cc45d0 100644 --- a/mm/slab.c +++ b/mm/slab.c @@ -389,7 +389,6 @@ struct kmem_cache { unsigned int buffer_size; u32 reciprocal_buffer_size; /* 3) touched by every alloc & free from the backend */ - struct kmem_list3 *nodelists[MAX_NUMNODES]; unsigned int flags; /* constant flags */ unsigned int num; /* # of objs per slab */ @@ -444,6 +443,17 @@ struct kmem_cache { int obj_offset; int obj_size; #endif + /* + * We put nodelists[] at the end of kmem_cache, because we want to size + * this array to nr_node_ids slots instead of MAX_NUMNODES + * (see kmem_cache_init()) + * We still use [MAX_NUMNODES] and not [1] or [0] because cache_cache + * is statically defined, so we reserve the max number of nodes. + */ + struct kmem_list3 *nodelists[MAX_NUMNODES]; + /* + * Do not add fields after nodelists[] + */ }; #define CFLGS_OFF_SLAB (0x80000000UL) @@ -678,9 +688,6 @@ static struct kmem_cache cache_cache = { .shared = 1, .buffer_size = sizeof(struct kmem_cache), .name = "kmem_cache", -#if DEBUG - .obj_size = sizeof(struct kmem_cache), -#endif }; #define BAD_ALIEN_MAGIC 0x01020304ul @@ -1440,6 +1447,15 @@ void __init kmem_cache_init(void) cache_cache.array[smp_processor_id()] = &initarray_cache.cache; cache_cache.nodelists[node] = &initkmem_list3[CACHE_CACHE]; + /* + * struct kmem_cache size depends on nr_node_ids, which + * can be less than MAX_NUMNODES. + */ + cache_cache.buffer_size = offsetof(struct kmem_cache, nodelists) + + nr_node_ids * sizeof(struct kmem_list3 *); +#if DEBUG + cache_cache.obj_size = cache_cache.buffer_size; +#endif cache_cache.buffer_size = ALIGN(cache_cache.buffer_size, cache_line_size()); cache_cache.reciprocal_buffer_size = |