2012/9/29 Christoph Lameter <cl@xxxxxxxxx>:
> Simplify setup and reduce code in kmem_cache_init(). This allows us to
> get rid of initarray_cache as well as the manual setup code for
> the kmem_cache and kmem_cache_node arrays during bootstrap.
>
> We introduce a new bootstrap state "PARTIAL" for slab that signals the
> creation of a kmem_cache boot cache.
>
> V1->V2: Get rid of initarray_cache as well.
>
> Signed-off-by: Christoph Lameter <cl@xxxxxxxxx>
> ---
> mm/slab.c | 51 ++++++++++++++++++---------------------------------
> 1 file changed, 18 insertions(+), 33 deletions(-)
>
> Index: linux/mm/slab.c
> ===================================================================
> --- linux.orig/mm/slab.c 2012-09-19 09:21:14.422971030 -0500
> +++ linux/mm/slab.c 2012-09-19 09:21:21.399115971 -0500
> @@ -572,8 +572,6 @@ static struct cache_names __initdata cac
> #undef CACHE
> };
>
> -static struct arraycache_init initarray_cache __initdata =
> - { {0, BOOT_CPUCACHE_ENTRIES, 1, 0} };
> static struct arraycache_init initarray_generic =
> { {0, BOOT_CPUCACHE_ENTRIES, 1, 0} };
>
> @@ -1596,12 +1594,9 @@ static void setup_nodelists_pointer(stru
> */
> void __init kmem_cache_init(void)
> {
> - size_t left_over;
> struct cache_sizes *sizes;
> struct cache_names *names;
> int i;
> - int order;
> - int node;
>
> kmem_cache = &kmem_cache_boot;
> setup_nodelists_pointer(kmem_cache);
> @@ -1645,36 +1640,17 @@ void __init kmem_cache_init(void)
> * 6) Resize the head arrays of the kmalloc caches to their final sizes.
> */
>
> - node = numa_mem_id();
> -
> /* 1) create the kmem_cache */
> - INIT_LIST_HEAD(&slab_caches);
> - list_add(&kmem_cache->list, &slab_caches);
> - kmem_cache->colour_off = cache_line_size();
> - kmem_cache->array[smp_processor_id()] = &initarray_cache.cache;
>
> /*
> * struct kmem_cache size depends on nr_node_ids & nr_cpu_ids
> */
> - kmem_cache->size = offsetof(struct kmem_cache, array[nr_cpu_ids]) +
> - nr_node_ids * sizeof(struct kmem_list3 *);
> - kmem_cache->object_size = kmem_cache->size;
> - kmem_cache->size = ALIGN(kmem_cache->object_size,
> - cache_line_size());
> - kmem_cache->reciprocal_buffer_size =
> - reciprocal_value(kmem_cache->size);
> -
> - for (order = 0; order < MAX_ORDER; order++) {
> - cache_estimate(order, kmem_cache->size,
> - cache_line_size(), 0, &left_over, &kmem_cache->num);
> - if (kmem_cache->num)
> - break;
> - }
> - BUG_ON(!kmem_cache->num);
> - kmem_cache->gfporder = order;
> - kmem_cache->colour = left_over / kmem_cache->colour_off;
> - kmem_cache->slab_size = ALIGN(kmem_cache->num * sizeof(kmem_bufctl_t) +
> - sizeof(struct slab), cache_line_size());
> + create_boot_cache(kmem_cache, "kmem_cache",
> + offsetof(struct kmem_cache, array[nr_cpu_ids]) +
> + nr_node_ids * sizeof(struct kmem_list3 *),
> + SLAB_HWCACHE_ALIGN);
> +
> + slab_state = PARTIAL;
>
> /* 2+3) create the kmalloc caches */
> sizes = malloc_sizes;
> @@ -1722,7 +1698,6 @@ void __init kmem_cache_init(void)
>
> ptr = kmalloc(sizeof(struct arraycache_init), GFP_NOWAIT);
>
> - BUG_ON(cpu_cache_get(kmem_cache) != &initarray_cache.cache);
> memcpy(ptr, cpu_cache_get(kmem_cache),
> sizeof(struct arraycache_init));
> /*
> @@ -2277,7 +2252,16 @@ static int __init_refok setup_cpu_cache(
>
> if (slab_state == DOWN) {
> /*
> - * Note: the first kmem_cache_create must create the cache
> + * Note: Creation of first cache (kmem_cache).
> + * The setup_list3s is taken care
> + * of by the caller of __kmem_cache_create
> + */
> + cachep->array[smp_processor_id()] = &initarray_generic.cache;
> + slab_state = PARTIAL;
> + } else
> + if (slab_state == PARTIAL) {
> + /*
> + * Note: the second kmem_cache_create must create the cache
> * that's used by kmalloc(24), otherwise the creation of
> * further caches will BUG().
> */
> @@ -2285,7 +2269,7 @@ static int __init_refok setup_cpu_cache(
>
> /*
> * If the cache that's used by kmalloc(sizeof(kmem_list3)) is
> - * the first cache, then we need to set up all its list3s,
> + * the second cache, then we need to set up all its list3s,
> * otherwise the creation of further caches will BUG().
> */
> set_up_list3s(cachep, SIZE_AC);
> @@ -2294,6 +2278,7 @@ static int __init_refok setup_cpu_cache(
> else
> slab_state = PARTIAL_ARRAYCACHE;
> } else {
> + /* Remaining boot caches */
> cachep->array[smp_processor_id()] =
> kmalloc(sizeof(struct arraycache_init), gfp);
>
> @@ -2389,22 +2374,6 @@ __kmem_cache_create (struct kmem_cache *
> size &= ~(BYTES_PER_WORD - 1);
> }
>
> - /* calculate the final buffer alignment: */
> -
> - /* 1) arch recommendation: can be overridden for debug */
> - if (flags & SLAB_HWCACHE_ALIGN) {
> - /*
> - * Default alignment: as specified by the arch code. Except if
> - * an object is really small, then squeeze multiple objects into
> - * one cacheline.
> - */
> - ralign = cache_line_size();
> - while (size <= ralign / 2)
> - ralign /= 2;
> - } else {
> - ralign = BYTES_PER_WORD;
> - }
> -
> /*
> * Redzoning and user store require word alignment or possibly larger.
> * Note this will be overridden by architecture or caller mandated
> @@ -2421,10 +2390,6 @@ __kmem_cache_create (struct kmem_cache *
> size &= ~(REDZONE_ALIGN - 1);
> }
>
> - /* 2) arch mandated alignment */
> - if (ralign < ARCH_SLAB_MINALIGN) {
> - ralign = ARCH_SLAB_MINALIGN;
> - }
> /* 3) caller mandated alignment */
> if (ralign < cachep->align) {
> ralign = cachep->align;
>
With this patch, the slab allocator doesn't properly calculate an
alignment value for SLAB_HWCACHE_ALIGN flag.
Do we need to shuffle patches?
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