From 73293c2f900d0adbb6a415b312cd57976d5ae242 Mon Sep 17 00:00:00 2001 From: Joonsoo Kim Date: Thu, 24 Oct 2013 10:07:37 +0900 Subject: 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 pfmemalloc. 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: Andi Kleen Signed-off-by: Joonsoo Kim Signed-off-by: Pekka Enberg --- mm/slab.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) (limited to 'mm/slab.c') diff --git a/mm/slab.c b/mm/slab.c index 2580db062df9..0b4ddafd8a03 100644 --- a/mm/slab.c +++ b/mm/slab.c @@ -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)) set_obj_pfmemalloc(&objp); } @@ -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); + SetPageSlabPfmemalloc(page); } memcg_bind_pages(cachep, cachep->gfporder); @@ -1809,9 +1810,10 @@ static void kmem_freepages(struct kmem_cache *cachep, void *addr) else sub_zone_page_state(page_zone(page), NR_SLAB_UNRECLAIMABLE, nr_freed); + + __ClearPageSlabPfmemalloc(page); while (i--) { BUG_ON(!PageSlab(page)); - __ClearPageSlabPfmemalloc(page); __ClearPageSlab(page); page++; } -- cgit v1.2.3-55-g7522