Commit 73293c2f authored by Joonsoo Kim's avatar Joonsoo Kim Committed by Pekka Enberg
Browse files

slab: correct pfmemalloc check

We checked pfmemalloc by slab unit, not page unit. You can see this
in is_slab_pfmemalloc(). So other pages don't need to be set/cleared

And, therefore we should check pfmemalloc in page flag of first page,
but current implementation don't do that. virt_to_head_page(obj) just
return 'struct page' of that object, not one of first page, since the SLAB
don't use __GFP_COMP when CONFIG_MMU. To get 'struct page' of first page,
we first get a slab and try to get it via virt_to_head_page(slab->s_mem).

Acked-by: default avatarAndi Kleen <>
Signed-off-by: default avatarJoonsoo Kim <>
Signed-off-by: default avatarPekka Enberg <>
parent 6e466452
......@@ -930,7 +930,8 @@ static void *__ac_put_obj(struct kmem_cache *cachep, struct array_cache *ac,
if (unlikely(pfmemalloc_active)) {
/* Some pfmemalloc slabs exist, check if this is one */
struct page *page = virt_to_head_page(objp);
struct slab *slabp = virt_to_slab(objp);
struct page *page = virt_to_head_page(slabp->s_mem);
if (PageSlabPfmemalloc(page))
......@@ -1776,7 +1777,7 @@ static void *kmem_getpages(struct kmem_cache *cachep, gfp_t flags, int nodeid)
__SetPageSlab(page + i);
if (page->pfmemalloc)
SetPageSlabPfmemalloc(page + i);
memcg_bind_pages(cachep, cachep->gfporder);
......@@ -1809,9 +1810,10 @@ static void kmem_freepages(struct kmem_cache *cachep, void *addr)
while (i--) {
Supports Markdown
0% or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment