Hello, Christoph.
2012/10/19 Christoph Lameter <cl@xxxxxxxxx>:
> Use a special function to create kmalloc caches and use that function in
> SLAB and SLUB.
>
> V1->V2:
> Do check for slasb state in slub's __kmem_cache_create to avoid
> unlocking a lock that was not taken
>
> Reviewed-by: Glauber Costa <glommer@xxxxxxxxxxxxx>
> Signed-off-by: Christoph Lameter <cl@xxxxxxxxx>
> ---
> mm/slab.c | 48 ++++++++++++++----------------------------------
> mm/slab.h | 5 +++++
> mm/slab_common.c | 32 ++++++++++++++++++++++++++++++++
> mm/slub.c | 36 +++---------------------------------
> 4 files changed, 54 insertions(+), 67 deletions(-)
>
> Index: linux/mm/slab.c
> ===================================================================
> --- linux.orig/mm/slab.c 2012-10-19 09:12:41.934366687 -0500
> +++ linux/mm/slab.c 2012-10-19 09:12:44.158404719 -0500
> @@ -1679,23 +1679,13 @@ void __init kmem_cache_init(void)
> * bug.
> */
>
> - sizes[INDEX_AC].cs_cachep = kmem_cache_zalloc(kmem_cache, GFP_NOWAIT);
> - sizes[INDEX_AC].cs_cachep->name = names[INDEX_AC].name;
> - sizes[INDEX_AC].cs_cachep->size = sizes[INDEX_AC].cs_size;
> - sizes[INDEX_AC].cs_cachep->object_size = sizes[INDEX_AC].cs_size;
> - sizes[INDEX_AC].cs_cachep->align = ARCH_KMALLOC_MINALIGN;
> - __kmem_cache_create(sizes[INDEX_AC].cs_cachep, ARCH_KMALLOC_FLAGS|SLAB_PANIC);
> - list_add(&sizes[INDEX_AC].cs_cachep->list, &slab_caches);
> + sizes[INDEX_AC].cs_cachep = create_kmalloc_cache(names[INDEX_AC].name,
> + sizes[INDEX_AC].cs_size, ARCH_KMALLOC_FLAGS);
>
> - if (INDEX_AC != INDEX_L3) {
> - sizes[INDEX_L3].cs_cachep = kmem_cache_zalloc(kmem_cache, GFP_NOWAIT);
> - sizes[INDEX_L3].cs_cachep->name = names[INDEX_L3].name;
> - sizes[INDEX_L3].cs_cachep->size = sizes[INDEX_L3].cs_size;
> - sizes[INDEX_L3].cs_cachep->object_size = sizes[INDEX_L3].cs_size;
> - sizes[INDEX_L3].cs_cachep->align = ARCH_KMALLOC_MINALIGN;
> - __kmem_cache_create(sizes[INDEX_L3].cs_cachep, ARCH_KMALLOC_FLAGS|SLAB_PANIC);
> - list_add(&sizes[INDEX_L3].cs_cachep->list, &slab_caches);
> - }
> + if (INDEX_AC != INDEX_L3)
> + sizes[INDEX_L3].cs_cachep =
> + create_kmalloc_cache(names[INDEX_L3].name,
> + sizes[INDEX_L3].cs_size, ARCH_KMALLOC_FLAGS);
>
> slab_early_init = 0;
>
> @@ -1707,24 +1697,14 @@ void __init kmem_cache_init(void)
> * Note for systems short on memory removing the alignment will
> * allow tighter packing of the smaller caches.
> */
> - if (!sizes->cs_cachep) {
> - sizes->cs_cachep = kmem_cache_zalloc(kmem_cache, GFP_NOWAIT);
> - sizes->cs_cachep->name = names->name;
> - sizes->cs_cachep->size = sizes->cs_size;
> - sizes->cs_cachep->object_size = sizes->cs_size;
> - sizes->cs_cachep->align = ARCH_KMALLOC_MINALIGN;
> - __kmem_cache_create(sizes->cs_cachep, ARCH_KMALLOC_FLAGS|SLAB_PANIC);
> - list_add(&sizes->cs_cachep->list, &slab_caches);
> - }
> + if (!sizes->cs_cachep)
> + sizes->cs_cachep = create_kmalloc_cache(names->name,
> + sizes->cs_size, ARCH_KMALLOC_FLAGS);
> +
> #ifdef CONFIG_ZONE_DMA
> - sizes->cs_dmacachep = kmem_cache_zalloc(kmem_cache, GFP_NOWAIT);
> - sizes->cs_dmacachep->name = names->name_dma;
> - sizes->cs_dmacachep->size = sizes->cs_size;
> - sizes->cs_dmacachep->object_size = sizes->cs_size;
> - sizes->cs_dmacachep->align = ARCH_KMALLOC_MINALIGN;
> - __kmem_cache_create(sizes->cs_dmacachep,
> - ARCH_KMALLOC_FLAGS|SLAB_CACHE_DMA| SLAB_PANIC);
> - list_add(&sizes->cs_dmacachep->list, &slab_caches);
> + sizes->cs_dmacachep = create_kmalloc_cache(
> + names->name_dma, sizes->cs_size,
> + SLAB_CACHE_DMA|ARCH_KMALLOC_FLAGS);
> #endif
> sizes++;
> names++;
> Index: linux/mm/slab.h
> ===================================================================
> --- linux.orig/mm/slab.h 2012-10-18 10:37:51.372631802 -0500
> +++ linux/mm/slab.h 2012-10-19 09:12:44.158404719 -0500
> @@ -35,6 +35,11 @@ extern struct kmem_cache *kmem_cache;
> /* Functions provided by the slab allocators */
> extern int __kmem_cache_create(struct kmem_cache *, unsigned long flags);
>
> +extern struct kmem_cache *create_kmalloc_cache(const char *name, size_t size,
> + unsigned long flags);
> +extern void create_boot_cache(struct kmem_cache *, const char *name,
> + size_t size, unsigned long flags);
> +
> #ifdef CONFIG_SLUB
> struct kmem_cache *__kmem_cache_alias(const char *name, size_t size,
> size_t align, unsigned long flags, void (*ctor)(void *));
> Index: linux/mm/slab_common.c
> ===================================================================
> --- linux.orig/mm/slab_common.c 2012-10-18 10:37:51.392632144 -0500
> +++ linux/mm/slab_common.c 2012-10-19 09:12:44.158404719 -0500
> @@ -192,3 +192,39 @@ int slab_is_available(void)
> {
> return slab_state >= UP;
> }
> +
> +#ifndef CONFIG_SLOB
> +/* Create a cache during boot when no slab services are available yet */
> +void __init create_boot_cache(struct kmem_cache *s, const char *name, size_t size,
> + unsigned long flags)
> +{
> + int err;
> +
> + s->name = name;
> + s->size = s->object_size = size;
> + s->align = ARCH_KMALLOC_MINALIGN;
> + err = __kmem_cache_create(s, flags);
> +
> + if (err)
> + panic("Creation of kmalloc slab %s size=%td failed. Reason %d\n",
> + name, size, err);
> +
> + list_add(&s->list, &slab_caches);
> + s->refcount = -1; /* Exempt from merging for now */
> +}
> +
> +struct kmem_cache *__init create_kmalloc_cache(const char *name, size_t size,
> + unsigned long flags)
> +{
> + struct kmem_cache *s = kmem_cache_zalloc(kmem_cache, GFP_NOWAIT);
> +
> + if (!s)
> + panic("Out of memory when creating slab %s\n", name);
> +
> + create_boot_cache(s, name, size, flags);
> + s->refcount = 1;
> + return s;
> +}
> +
> +#endif /* !CONFIG_SLOB */
> +
> Index: linux/mm/slub.c
> ===================================================================
> --- linux.orig/mm/slub.c 2012-10-19 09:12:21.830023016 -0500
> +++ linux/mm/slub.c 2012-10-19 09:12:44.162404786 -0500
> @@ -3255,32 +3255,6 @@ static int __init setup_slub_nomerge(cha
>
> __setup("slub_nomerge", setup_slub_nomerge);
>
> -static struct kmem_cache *__init create_kmalloc_cache(const char *name,
> - int size, unsigned int flags)
> -{
> - struct kmem_cache *s;
> -
> - s = kmem_cache_zalloc(kmem_cache, GFP_NOWAIT);
> -
> - s->name = name;
> - s->size = s->object_size = size;
> - s->align = ARCH_KMALLOC_MINALIGN;
> -
> - /*
> - * This function is called with IRQs disabled during early-boot on
> - * single CPU so there's no need to take slab_mutex here.
> - */
> - if (kmem_cache_open(s, flags))
> - goto panic;
> -
> - list_add(&s->list, &slab_caches);
> - return s;
> -
> -panic:
> - panic("Creation of kmalloc slab %s size=%d failed.\n", name, size);
> - return NULL;
> -}
> -
> /*
> * Conversion table for small slabs sizes / 8 to the index in the
> * kmalloc array. This is necessary for slabs < 192 since we have non power
> @@ -3958,6 +3932,10 @@ int __kmem_cache_create(struct kmem_cach
> if (err)
> return err;
>
> + /* Mutex is not taken during early boot */
> + if (slab_state <= UP)
> + return 0;
> +
> mutex_unlock(&slab_mutex);
> err = sysfs_slab_add(s);
> mutex_lock(&slab_mutex);
>
With above change, "if (slab_state < FULL) ~~" in sysfs_slab_add() is useless.
So, how about removing it?
Acked-by: Joonsoo Kim <js1304@xxxxxxxxx>
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