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mm/slab: clean up cache type determination 

Current cache type determination code is open-code and looks not
understandable.  Following patch will introduce one more cache type and
it would make code more complex.  So, before it happens, this patch
abstracts these codes.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Joonsoo Kim 2016-03-15 14:54:35 -07:00 committed by Linus Torvalds
parent 832a15d209
commit 158e319bba
1 changed files with 71 additions and 34 deletions
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105
mm/slab.c
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@ -2023,6 +2023,64 @@ __kmem_cache_alias(const char *name, size_t size, size_t align,
return cachep;
}
static bool set_off_slab_cache(struct kmem_cache *cachep,
size_t size, unsigned long flags)
{
size_t left;
cachep->num = 0;
/*
* Determine if the slab management is 'on' or 'off' slab.
* (bootstrapping cannot cope with offslab caches so don't do
* it too early on. Always use on-slab management when
* SLAB_NOLEAKTRACE to avoid recursive calls into kmemleak)
*/
if (size < OFF_SLAB_MIN_SIZE)
return false;
if (slab_early_init)
return false;
if (flags & SLAB_NOLEAKTRACE)
return false;
/*
* Size is large, assume best to place the slab management obj
* off-slab (should allow better packing of objs).
*/
left = calculate_slab_order(cachep, size, flags | CFLGS_OFF_SLAB);
if (!cachep->num)
return false;
/*
* If the slab has been placed off-slab, and we have enough space then
* move it on-slab. This is at the expense of any extra colouring.
*/
if (left >= cachep->num * sizeof(freelist_idx_t))
return false;
cachep->colour = left / cachep->colour_off;
return true;
}
static bool set_on_slab_cache(struct kmem_cache *cachep,
size_t size, unsigned long flags)
{
size_t left;
cachep->num = 0;
left = calculate_slab_order(cachep, size, flags);
if (!cachep->num)
return false;
cachep->colour = left / cachep->colour_off;
return true;
}
/**
* __kmem_cache_create - Create a cache.
* @cachep: cache management descriptor
@ -2047,7 +2105,6 @@ __kmem_cache_alias(const char *name, size_t size, size_t align,
int
__kmem_cache_create (struct kmem_cache *cachep, unsigned long flags)
{
size_t left_over, freelist_size;
size_t ralign = BYTES_PER_WORD;
gfp_t gfp;
int err;
@ -2098,6 +2155,10 @@ __kmem_cache_create (struct kmem_cache *cachep, unsigned long flags)
* 4) Store it.
*/
cachep->align = ralign;
cachep->colour_off = cache_line_size();
/* Offset must be a multiple of the alignment. */
if (cachep->colour_off < cachep->align)
cachep->colour_off = cachep->align;
if (slab_is_available())
gfp = GFP_KERNEL;
@ -2152,43 +2213,18 @@ __kmem_cache_create (struct kmem_cache *cachep, unsigned long flags)
}
#endif
/*
* Determine if the slab management is 'on' or 'off' slab.
* (bootstrapping cannot cope with offslab caches so don't do
* it too early on. Always use on-slab management when
* SLAB_NOLEAKTRACE to avoid recursive calls into kmemleak)
*/
if (size >= OFF_SLAB_MIN_SIZE && !slab_early_init &&
!(flags & SLAB_NOLEAKTRACE)) {
/*
* Size is large, assume best to place the slab management obj
* off-slab (should allow better packing of objs).
*/
if (set_off_slab_cache(cachep, size, flags)) {
flags |= CFLGS_OFF_SLAB;
goto done;
}
left_over = calculate_slab_order(cachep, size, flags);
if (set_on_slab_cache(cachep, size, flags))
goto done;
if (!cachep->num)
return -E2BIG;
return -E2BIG;
freelist_size = cachep->num * sizeof(freelist_idx_t);
/*
* If the slab has been placed off-slab, and we have enough space then
* move it on-slab. This is at the expense of any extra colouring.
*/
if (flags & CFLGS_OFF_SLAB && left_over >= freelist_size) {
flags &= ~CFLGS_OFF_SLAB;
left_over -= freelist_size;
}
cachep->colour_off = cache_line_size();
/* Offset must be a multiple of the alignment. */
if (cachep->colour_off < cachep->align)
cachep->colour_off = cachep->align;
cachep->colour = left_over / cachep->colour_off;
cachep->freelist_size = freelist_size;
done:
cachep->freelist_size = cachep->num * sizeof(freelist_idx_t);
cachep->flags = flags;
cachep->allocflags = __GFP_COMP;
if (CONFIG_ZONE_DMA_FLAG && (flags & SLAB_CACHE_DMA))
@ -2209,7 +2245,8 @@ __kmem_cache_create (struct kmem_cache *cachep, unsigned long flags)
#endif
if (OFF_SLAB(cachep)) {
cachep->freelist_cache = kmalloc_slab(freelist_size, 0u);
cachep->freelist_cache =
kmalloc_slab(cachep->freelist_size, 0u);
/*
* This is a possibility for one of the kmalloc_{dma,}_caches.
* But since we go off slab only for object size greater than