Hello, Christoph.
On Thu, Jan 10, 2013 at 07:12:17PM +0000, Christoph Lameter wrote:
> The kmalloc array is created in similar ways in both SLAB
> and SLUB. Create a common function and have both allocators
> call that function.
>
> V1->V2:
> Whitespace cleanup
>
> Reviewed-by: Glauber Costa <glommer@xxxxxxxxxxxxx>
> Signed-off-by: Christoph Lameter <cl@xxxxxxxxx>
>
> Index: linux/mm/slab.c
> ===================================================================
> --- linux.orig/mm/slab.c 2013-01-10 09:55:49.493734836 -0600
> +++ linux/mm/slab.c 2013-01-10 09:55:50.169745534 -0600
> @@ -1625,30 +1625,6 @@ void __init kmem_cache_init(void)
>
> slab_early_init = 0;
>
> - for (i = 1; i < PAGE_SHIFT + MAX_ORDER; i++) {
> - size_t cs_size = kmalloc_size(i);
> -
> - if (cs_size < KMALLOC_MIN_SIZE)
> - continue;
> -
> - if (!kmalloc_caches[i]) {
> - /*
> - * For performance, all the general caches are L1 aligned.
> - * This should be particularly beneficial on SMP boxes, as it
> - * eliminates "false sharing".
> - * Note for systems short on memory removing the alignment will
> - * allow tighter packing of the smaller caches.
> - */
> - kmalloc_caches[i] = create_kmalloc_cache("kmalloc",
> - cs_size, ARCH_KMALLOC_FLAGS);
> - }
> -
> -#ifdef CONFIG_ZONE_DMA
> - kmalloc_dma_caches[i] = create_kmalloc_cache(
> - "kmalloc-dma", cs_size,
> - SLAB_CACHE_DMA|ARCH_KMALLOC_FLAGS);
> -#endif
> - }
> /* 4) Replace the bootstrap head arrays */
> {
> struct array_cache *ptr;
> @@ -1694,29 +1670,7 @@ void __init kmem_cache_init(void)
> }
> }
>
> - slab_state = UP;
> -
> - /* Create the proper names */
> - for (i = 1; i < PAGE_SHIFT + MAX_ORDER; i++) {
> - char *s;
> - struct kmem_cache *c = kmalloc_caches[i];
> -
> - if (!c)
> - continue;
> -
> - s = kasprintf(GFP_NOWAIT, "kmalloc-%d", kmalloc_size(i));
> -
> - BUG_ON(!s);
> - c->name = s;
> -
> -#ifdef CONFIG_ZONE_DMA
> - c = kmalloc_dma_caches[i];
> - BUG_ON(!c);
> - s = kasprintf(GFP_NOWAIT, "dma-kmalloc-%d", kmalloc_size(i));
> - BUG_ON(!s);
> - c->name = s;
> -#endif
> - }
> + create_kmalloc_caches(ARCH_KMALLOC_FLAGS);
> }
>
> void __init kmem_cache_init_late(void)
> Index: linux/mm/slab.h
> ===================================================================
> --- linux.orig/mm/slab.h 2013-01-10 09:54:18.000315420 -0600
> +++ linux/mm/slab.h 2013-01-10 09:55:50.169745534 -0600
> @@ -35,6 +35,12 @@ extern struct kmem_cache *kmem_cache;
> unsigned long calculate_alignment(unsigned long flags,
> unsigned long align, unsigned long size);
>
> +#ifndef CONFIG_SLOB
> +/* Kmalloc array related functions */
> +void create_kmalloc_caches(unsigned long);
> +#endif
> +
> +
> /* Functions provided by the slab allocators */
> extern int __kmem_cache_create(struct kmem_cache *, unsigned long flags);
>
> Index: linux/mm/slab_common.c
> ===================================================================
> --- linux.orig/mm/slab_common.c 2013-01-10 09:55:49.489734859 -0600
> +++ linux/mm/slab_common.c 2013-01-10 09:55:50.169745534 -0600
> @@ -327,6 +327,60 @@ struct kmem_cache *kmalloc_dma_caches[KM
> EXPORT_SYMBOL(kmalloc_dma_caches);
> #endif
>
> +/*
> + * Create the kmalloc array. Some of the regular kmalloc arrays
> + * may already have been created because they were needed to
> + * enable allocations for slab creation.
> + */
> +void __init create_kmalloc_caches(unsigned long flags)
> +{
> + int i;
> +
> + /* Caches that are not of the two-to-the-power-of size */
> + if (KMALLOC_MIN_SIZE <= 32 && !kmalloc_caches[1])
> + kmalloc_caches[1] = create_kmalloc_cache(NULL, 96, flags);
> +
> + if (KMALLOC_MIN_SIZE <= 64 && !kmalloc_caches[2])
> + kmalloc_caches[2] = create_kmalloc_cache(NULL, 192, flags);
> +
> + for (i = KMALLOC_SHIFT_LOW; i <= KMALLOC_SHIFT_HIGH; i++)
> + if (!kmalloc_caches[i])
> + kmalloc_caches[i] = create_kmalloc_cache(NULL,
> + 1 << i, flags);
> +
In case of the SLUB, create_kmalloc_cache with @NULL break the system
if slub_debug is used.
Call flow is like as below.
create_kmalloc_cache -> create_boot_cache -> __kmem_cache_create ->
kmem_cache_open -> kmem_cache_flag.
In kmem_cache_flag, strncmp is excecuted with name, that is, NULL.
> + /* Kmalloc array is now usable */
> + slab_state = UP;
> +
> + for (i = 0; i <= KMALLOC_SHIFT_HIGH; i++) {
> + struct kmem_cache *s = kmalloc_caches[i];
> + char *n;
> +
> + if (s) {
> + n = kasprintf(GFP_NOWAIT, "kmalloc-%d", kmalloc_size(i));
> +
> + BUG_ON(!n);
> + s->name = n;
> + }
> + }
> +
> +#ifdef CONFIG_ZONE_DMA
> + for (i = 0; i <= KMALLOC_SHIFT_HIGH; i++) {
> + struct kmem_cache *s = kmalloc_caches[i];
> +
> + if (s) {
> + int size = kmalloc_size(i);
> + char *n = kasprintf(GFP_NOWAIT,
> + "dma-kmalloc-%d", size);
> +
> + BUG_ON(!n);
> + kmalloc_dma_caches[i] = create_kmalloc_cache(n,
> + size, SLAB_CACHE_DMA | flags);
> + }
> + }
> +#endif
> +}
> +
> +
> #endif /* !CONFIG_SLOB */
>
>
> Index: linux/mm/slub.c
> ===================================================================
> --- linux.orig/mm/slub.c 2013-01-10 09:55:49.489734859 -0600
> +++ linux/mm/slub.c 2013-01-10 09:55:50.173745560 -0600
> @@ -3633,7 +3633,6 @@ void __init kmem_cache_init(void)
> static __initdata struct kmem_cache boot_kmem_cache,
> boot_kmem_cache_node;
> int i;
> - int caches = 2;
>
> if (debug_guardpage_minorder())
> slub_max_order = 0;
> @@ -3703,64 +3702,16 @@ void __init kmem_cache_init(void)
> size_index[size_index_elem(i)] = 8;
> }
>
> - /* Caches that are not of the two-to-the-power-of size */
> - if (KMALLOC_MIN_SIZE <= 32) {
> - kmalloc_caches[1] = create_kmalloc_cache("kmalloc-96", 96, 0);
> - caches++;
> - }
> -
> - if (KMALLOC_MIN_SIZE <= 64) {
> - kmalloc_caches[2] = create_kmalloc_cache("kmalloc-192", 192, 0);
> - caches++;
> - }
> -
> - for (i = KMALLOC_SHIFT_LOW; i <= KMALLOC_SHIFT_HIGH; i++) {
> - kmalloc_caches[i] = create_kmalloc_cache("kmalloc", 1 << i, 0);
> - caches++;
> - }
> -
> - slab_state = UP;
> -
> - /* Provide the correct kmalloc names now that the caches are up */
> - if (KMALLOC_MIN_SIZE <= 32) {
> - kmalloc_caches[1]->name = kstrdup(kmalloc_caches[1]->name, GFP_NOWAIT);
> - BUG_ON(!kmalloc_caches[1]->name);
> - }
> -
> - if (KMALLOC_MIN_SIZE <= 64) {
> - kmalloc_caches[2]->name = kstrdup(kmalloc_caches[2]->name, GFP_NOWAIT);
> - BUG_ON(!kmalloc_caches[2]->name);
> - }
> -
> - for (i = KMALLOC_SHIFT_LOW; i <= KMALLOC_SHIFT_HIGH; i++) {
> - char *s = kasprintf(GFP_NOWAIT, "kmalloc-%d", 1 << i);
> -
> - BUG_ON(!s);
> - kmalloc_caches[i]->name = s;
> - }
> + create_kmalloc_caches(0);
>
> #ifdef CONFIG_SMP
> register_cpu_notifier(&slab_notifier);
> #endif
>
> -#ifdef CONFIG_ZONE_DMA
> - for (i = 0; i <= KMALLOC_SHIFT_HIGH; i++) {
> - struct kmem_cache *s = kmalloc_caches[i];
> -
> - if (s && s->size) {
> - char *name = kasprintf(GFP_NOWAIT,
> - "dma-kmalloc-%d", s->object_size);
> -
> - BUG_ON(!name);
> - kmalloc_dma_caches[i] = create_kmalloc_cache(name,
> - s->object_size, SLAB_CACHE_DMA);
> - }
> - }
> -#endif
> printk(KERN_INFO
> - "SLUB: Genslabs=%d, HWalign=%d, Order=%d-%d, MinObjects=%d,"
> + "SLUB: HWalign=%d, Order=%d-%d, MinObjects=%d,"
> " CPUs=%d, Nodes=%d\n",
> - caches, cache_line_size(),
> + cache_line_size(),
> slub_min_order, slub_max_order, slub_min_objects,
> nr_cpu_ids, nr_node_ids);
> }
>
> --
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