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Commit a380a3c7 authored by Christoph Lameter's avatar Christoph Lameter Committed by Linus Torvalds
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slub: create new ___slab_alloc function that can be called with irqs disabled 



Bulk alloc needs a function like that because it enables interrupts before
calling __slab_alloc which promptly disables them again using the expensive
local_irq_save().

Signed-off-by: default avatarChristoph Lameter <cl@linux.com>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Alexander Duyck <alexander.h.duyck@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 21fa8442

mm/slub.c

+29 −15
Original line number Diff line number Diff line
@@ -2295,23 +2295,15 @@ static inline void *get_freelist(struct kmem_cache *s, struct page *page) 
 * And if we were unable to get a new slab from the partial slab lists then

 * we need to allocate a new slab. This is the slowest path since it involves

 * a call to the page allocator and the setup of a new slab.

 *

 * Version of __slab_alloc to use when we know that interrupts are

 * already disabled (which is the case for bulk allocation).

 */

static void *__slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,

static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,

			  unsigned long addr, struct kmem_cache_cpu *c)

{

	void *freelist;

	struct page *page;

	unsigned long flags;



	local_irq_save(flags);

#ifdef CONFIG_PREEMPT

	/*

	 * We may have been preempted and rescheduled on a different

	 * cpu before disabling interrupts. Need to reload cpu area

	 * pointer.

	 */

	c = this_cpu_ptr(s->cpu_slab);

#endif



	page = c->page;

	if (!page)
@@ -2369,7 +2361,6 @@ static void *__slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node, 
	VM_BUG_ON(!c->page->frozen);

	c->freelist = get_freepointer(s, freelist);

	c->tid = next_tid(c->tid);

	local_irq_restore(flags);

	return freelist;



new_slab:
@@ -2386,7 +2377,6 @@ static void *__slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node, 


	if (unlikely(!freelist)) {

		slab_out_of_memory(s, gfpflags, node);

		local_irq_restore(flags);

		return NULL;

	}
@@ -2402,10 +2392,34 @@ static void *__slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node, 
	deactivate_slab(s, page, get_freepointer(s, freelist));

	c->page = NULL;

	c->freelist = NULL;

	local_irq_restore(flags);

	return freelist;

}



/*

 * Another one that disabled interrupt and compensates for possible

 * cpu changes by refetching the per cpu area pointer.

 */

static void *__slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,

			  unsigned long addr, struct kmem_cache_cpu *c)

{

	void *p;

	unsigned long flags;



	local_irq_save(flags);

#ifdef CONFIG_PREEMPT

	/*

	 * We may have been preempted and rescheduled on a different

	 * cpu before disabling interrupts. Need to reload cpu area

	 * pointer.

	 */

	c = this_cpu_ptr(s->cpu_slab);

#endif



	p = ___slab_alloc(s, gfpflags, node, addr, c);

	local_irq_restore(flags);

	return p;

}



/*

 * Inlined fastpath so that allocation functions (kmalloc, kmem_cache_alloc)

 * have the fastpath folded into their functions. So no function call