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Commit 0c3aa83e authored by Joonsoo Kim's avatar Joonsoo Kim Committed by Pekka Enberg
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slab: change return type of kmem_getpages() to struct page 



It is more understandable that kmem_getpages() return struct page.
And, with this, we can reduce one translation from virt addr to page and
makes better code than before. Below is a change of this patch.

* Before
   text	   data	    bss	    dec	    hex	filename
  22123	  23434	      4	  45561	   b1f9	mm/slab.o

* After
   text	   data	    bss	    dec	    hex	filename
  22074	  23434	      4	  45512	   b1c8	mm/slab.o

And this help following patch to remove struct slab's colouroff.

Acked-by: default avatarAndi Kleen <ak@linux.intel.com>
Acked-by: default avatarChristoph Lameter <cl@linux.com>
Signed-off-by: default avatarJoonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: default avatarPekka Enberg <penberg@iki.fi>
parent 73293c2f

mm/slab.c

+30 −30
Original line number Diff line number Diff line
@@ -205,7 +205,7 @@ typedef unsigned int kmem_bufctl_t; 
struct slab_rcu {

	struct rcu_head head;

	struct kmem_cache *cachep;

	void *addr;

	struct page *page;

};



/*
@@ -1737,7 +1737,8 @@ slab_out_of_memory(struct kmem_cache *cachep, gfp_t gfpflags, int nodeid) 
 * did not request dmaable memory, we might get it, but that

 * would be relatively rare and ignorable.

 */

static void *kmem_getpages(struct kmem_cache *cachep, gfp_t flags, int nodeid)

static struct page *kmem_getpages(struct kmem_cache *cachep, gfp_t flags,

								int nodeid)

{

	struct page *page;

	int nr_pages;
@@ -1790,16 +1791,15 @@ static void *kmem_getpages(struct kmem_cache *cachep, gfp_t flags, int nodeid) 
			kmemcheck_mark_unallocated_pages(page, nr_pages);

	}



	return page_address(page);

	return page;

}



/*

 * Interface to system's page release.

 */

static void kmem_freepages(struct kmem_cache *cachep, void *addr)

static void kmem_freepages(struct kmem_cache *cachep, struct page *page)

{

	unsigned long i = (1 << cachep->gfporder);

	struct page *page = virt_to_page(addr);

	const unsigned long nr_freed = i;



	kmemcheck_free_shadow(page, cachep->gfporder);
@@ -1821,7 +1821,7 @@ static void kmem_freepages(struct kmem_cache *cachep, void *addr) 
	memcg_release_pages(cachep, cachep->gfporder);

	if (current->reclaim_state)

		current->reclaim_state->reclaimed_slab += nr_freed;

	free_memcg_kmem_pages((unsigned long)addr, cachep->gfporder);

	__free_memcg_kmem_pages(page, cachep->gfporder);

}



static void kmem_rcu_free(struct rcu_head *head)
@@ -1829,7 +1829,7 @@ static void kmem_rcu_free(struct rcu_head *head) 
	struct slab_rcu *slab_rcu = (struct slab_rcu *)head;

	struct kmem_cache *cachep = slab_rcu->cachep;



	kmem_freepages(cachep, slab_rcu->addr);

	kmem_freepages(cachep, slab_rcu->page);

	if (OFF_SLAB(cachep))

		kmem_cache_free(cachep->slabp_cache, slab_rcu);

}
@@ -2048,7 +2048,7 @@ static void slab_destroy_debugcheck(struct kmem_cache *cachep, struct slab *slab 
 */

static void slab_destroy(struct kmem_cache *cachep, struct slab *slabp)

{

	void *addr = slabp->s_mem - slabp->colouroff;

	struct page *page = virt_to_head_page(slabp->s_mem);



	slab_destroy_debugcheck(cachep, slabp);

	if (unlikely(cachep->flags & SLAB_DESTROY_BY_RCU)) {
@@ -2056,10 +2056,10 @@ static void slab_destroy(struct kmem_cache *cachep, struct slab *slabp) 


		slab_rcu = (struct slab_rcu *)slabp;

		slab_rcu->cachep = cachep;

		slab_rcu->addr = addr;

		slab_rcu->page = page;

		call_rcu(&slab_rcu->head, kmem_rcu_free);

	} else {

		kmem_freepages(cachep, addr);

		kmem_freepages(cachep, page);

		if (OFF_SLAB(cachep))

			kmem_cache_free(cachep->slabp_cache, slabp);

	}
@@ -2604,11 +2604,12 @@ int __kmem_cache_shutdown(struct kmem_cache *cachep) 
 * kmem_find_general_cachep till the initialization is complete.

 * Hence we cannot have slabp_cache same as the original cache.

 */

static struct slab *alloc_slabmgmt(struct kmem_cache *cachep, void *objp,

				   int colour_off, gfp_t local_flags,

				   int nodeid)

static struct slab *alloc_slabmgmt(struct kmem_cache *cachep,

				   struct page *page, int colour_off,

				   gfp_t local_flags, int nodeid)

{

	struct slab *slabp;

	void *addr = page_address(page);



	if (OFF_SLAB(cachep)) {

		/* Slab management obj is off-slab. */
@@ -2625,12 +2626,12 @@ static struct slab *alloc_slabmgmt(struct kmem_cache *cachep, void *objp, 
		if (!slabp)

			return NULL;

	} else {

		slabp = objp + colour_off;

		slabp = addr + colour_off;

		colour_off += cachep->slab_size;

	}

	slabp->inuse = 0;

	slabp->colouroff = colour_off;

	slabp->s_mem = objp + colour_off;

	slabp->s_mem = addr + colour_off;

	slabp->nodeid = nodeid;

	slabp->free = 0;

	return slabp;
@@ -2741,12 +2742,9 @@ static void slab_put_obj(struct kmem_cache *cachep, struct slab *slabp, 
 * virtual address for kfree, ksize, and slab debugging.

 */

static void slab_map_pages(struct kmem_cache *cache, struct slab *slab,

			   void *addr)

			   struct page *page)

{

	int nr_pages;

	struct page *page;



	page = virt_to_page(addr);



	nr_pages = 1;

	if (likely(!PageCompound(page)))
@@ -2764,7 +2762,7 @@ static void slab_map_pages(struct kmem_cache *cache, struct slab *slab, 
 * kmem_cache_alloc() when there are no active objs left in a cache.

 */

static int cache_grow(struct kmem_cache *cachep,

		gfp_t flags, int nodeid, void *objp)

		gfp_t flags, int nodeid, struct page *page)

{

	struct slab *slabp;

	size_t offset;
@@ -2807,18 +2805,18 @@ static int cache_grow(struct kmem_cache *cachep, 
	 * Get mem for the objs.  Attempt to allocate a physical page from

	 * 'nodeid'.

	 */

	if (!objp)

		objp = kmem_getpages(cachep, local_flags, nodeid);

	if (!objp)

	if (!page)

		page = kmem_getpages(cachep, local_flags, nodeid);

	if (!page)

		goto failed;



	/* Get slab management. */

	slabp = alloc_slabmgmt(cachep, objp, offset,

	slabp = alloc_slabmgmt(cachep, page, offset,

			local_flags & ~GFP_CONSTRAINT_MASK, nodeid);

	if (!slabp)

		goto opps1;



	slab_map_pages(cachep, slabp, objp);

	slab_map_pages(cachep, slabp, page);



	cache_init_objs(cachep, slabp);
@@ -2834,7 +2832,7 @@ static int cache_grow(struct kmem_cache *cachep, 
	spin_unlock(&n->list_lock);

	return 1;

opps1:

	kmem_freepages(cachep, objp);

	kmem_freepages(cachep, page);

failed:

	if (local_flags & __GFP_WAIT)

		local_irq_disable();
@@ -3250,18 +3248,20 @@ retry: 
		 * We may trigger various forms of reclaim on the allowed

		 * set and go into memory reserves if necessary.

		 */

		struct page *page;



		if (local_flags & __GFP_WAIT)

			local_irq_enable();

		kmem_flagcheck(cache, flags);

		obj = kmem_getpages(cache, local_flags, numa_mem_id());

		page = kmem_getpages(cache, local_flags, numa_mem_id());

		if (local_flags & __GFP_WAIT)

			local_irq_disable();

		if (obj) {

		if (page) {

			/*

			 * Insert into the appropriate per node queues

			 */

			nid = page_to_nid(virt_to_page(obj));

			if (cache_grow(cache, flags, nid, obj)) {

			nid = page_to_nid(page);

			if (cache_grow(cache, flags, nid, page)) {

				obj = ____cache_alloc_node(cache,

					flags | GFP_THISNODE, nid);

				if (!obj)