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: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Roman Gushchin <guro@fb.com>
Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Tested-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
This commit is contained in:
Vlastimil Babka 2021-10-26 16:35:02 +02:00
parent fb012e278d
commit 45387b8c14

View File

@ -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);