Commit 45387b8c authored by Vlastimil Babka's avatar Vlastimil Babka
Browse files

mm/slub: Convert alloc_slab_page() to return a struct slab 



Preparatory, callers convert back to struct page for now.

Also move setting page flags to alloc_slab_page() where we still operate
on a struct page. This means the page->slab_cache pointer is now set
later than the PageSlab flag, which could theoretically confuse some pfn
walker assuming PageSlab means there would be a valid cache pointer. But
as the code had no barriers and used __set_bit() anyway, it could have
happened already, so there shouldn't be such a walker.

Signed-off-by: default avatarVlastimil Babka <vbabka@suse.cz>
Reviewed-by: default avatarRoman Gushchin <guro@fb.com>
Reviewed-by: default avatarHyeonggon Yoo <42.hyeyoo@gmail.com>
Tested-by: default avatarHyeonggon Yoo <42.hyeyoo@gmail.com>
parent fb012e27

mm/slub.c

+16 −10
Original line number Diff line number Diff line
@@ -1788,18 +1788,27 @@ static void *setup_object(struct kmem_cache *s, struct page *page, 
/*

 * Slab allocation and freeing

 */

static inline struct page *alloc_slab_page(struct kmem_cache *s,

static inline struct slab *alloc_slab_page(struct kmem_cache *s,

		gfp_t flags, int node, struct kmem_cache_order_objects oo)

{

	struct page *page;

	struct folio *folio;

	struct slab *slab;

	unsigned int order = oo_order(oo);



	if (node == NUMA_NO_NODE)

		page = alloc_pages(flags, order);

		folio = (struct folio *)alloc_pages(flags, order);

	else

		page = __alloc_pages_node(node, flags, order);

		folio = (struct folio *)__alloc_pages_node(node, flags, order);



	return page;

	if (!folio)

		return NULL;



	slab = folio_slab(folio);

	__folio_set_slab(folio);

	if (page_is_pfmemalloc(folio_page(folio, 0)))

		slab_set_pfmemalloc(slab);



	return slab;

}



#ifdef CONFIG_SLAB_FREELIST_RANDOM
@@ -1932,7 +1941,7 @@ static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node) 
	if ((alloc_gfp & __GFP_DIRECT_RECLAIM) && oo_order(oo) > oo_order(s->min))

		alloc_gfp = (alloc_gfp | __GFP_NOMEMALLOC) & ~(__GFP_RECLAIM|__GFP_NOFAIL);



	page = alloc_slab_page(s, alloc_gfp, node, oo);

	page = slab_page(alloc_slab_page(s, alloc_gfp, node, oo));

	if (unlikely(!page)) {

		oo = s->min;

		alloc_gfp = flags;
@@ -1940,7 +1949,7 @@ static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node) 
		 * Allocation may have failed due to fragmentation.

		 * Try a lower order alloc if possible

		 */

		page = alloc_slab_page(s, alloc_gfp, node, oo);

		page = slab_page(alloc_slab_page(s, alloc_gfp, node, oo));

		if (unlikely(!page))

			goto out;

		stat(s, ORDER_FALLBACK);
@@ -1951,9 +1960,6 @@ static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node) 
	account_slab(page_slab(page), oo_order(oo), s, flags);



	page->slab_cache = s;

	__SetPageSlab(page);

	if (page_is_pfmemalloc(page))

		SetPageSlabPfmemalloc(page);



	kasan_poison_slab(page);