From 02d65d6fb1aae151570c8bfd1bd77a8153d2e607 Mon Sep 17 00:00:00 2001 From: Sidhartha Kumar Date: Fri, 6 Jan 2023 15:52:51 -0600 Subject: [PATCH] mm: introduce folio_is_pfmemalloc Add a folio equivalent for page_is_pfmemalloc. This removes two instances of page_is_pfmemalloc(folio_page(folio, 0)) so the folio can be used directly. Link: https://lkml.kernel.org/r/20230106215251.599222-1-sidhartha.kumar@oracle.com Suggested-by: Matthew Wilcox Signed-off-by: Sidhartha Kumar Reviewed-by: Matthew Wilcox (Oracle) Reviewed-by: SeongJae Park Acked-by: Vlastimil Babka Signed-off-by: Andrew Morton --- include/linux/mm.h | 15 +++++++++++++++ mm/slab.c | 2 +- mm/slub.c | 2 +- 3 files changed, 17 insertions(+), 2 deletions(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index 8a8563359946..76c97cb8ee9a 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1926,6 +1926,21 @@ static inline bool page_is_pfmemalloc(const struct page *page) return (uintptr_t)page->lru.next & BIT(1); } +/* + * Return true only if the folio has been allocated with + * ALLOC_NO_WATERMARKS and the low watermark was not + * met implying that the system is under some pressure. + */ +static inline bool folio_is_pfmemalloc(const struct folio *folio) +{ + /* + * lru.next has bit 1 set if the page is allocated from the + * pfmemalloc reserves. Callers may simply overwrite it if + * they do not need to preserve that information. + */ + return (uintptr_t)folio->lru.next & BIT(1); +} + /* * Only to be called by the page allocator on a freshly allocated * page. diff --git a/mm/slab.c b/mm/slab.c index 7a269db050ee..b77be9c6d6b1 100644 --- a/mm/slab.c +++ b/mm/slab.c @@ -1373,7 +1373,7 @@ static struct slab *kmem_getpages(struct kmem_cache *cachep, gfp_t flags, /* Make the flag visible before any changes to folio->mapping */ smp_wmb(); /* Record if ALLOC_NO_WATERMARKS was set when allocating the slab */ - if (sk_memalloc_socks() && page_is_pfmemalloc(folio_page(folio, 0))) + if (sk_memalloc_socks() && folio_is_pfmemalloc(folio)) slab_set_pfmemalloc(slab); return slab; diff --git a/mm/slub.c b/mm/slub.c index 13459c69095a..67020074ecb4 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -1859,7 +1859,7 @@ static inline struct slab *alloc_slab_page(gfp_t flags, int node, __folio_set_slab(folio); /* Make the flag visible before any changes to folio->mapping */ smp_wmb(); - if (page_is_pfmemalloc(folio_page(folio, 0))) + if (folio_is_pfmemalloc(folio)) slab_set_pfmemalloc(slab); return slab; -- 2.25.1