From cc465c3b23f8db1896c1197d2f5799e97f6e617b Mon Sep 17 00:00:00 2001 From: "Matthew Wilcox (Oracle)" Date: Mon, 4 Oct 2021 14:45:58 +0100 Subject: [PATCH] mm/slub: Convert detached_freelist to use a struct slab This gives us a little bit of extra typesafety as we know that nobody called virt_to_page() instead of virt_to_head_page(). [ vbabka@suse.cz: Use folio as intermediate step when filtering out large kmalloc pages ] Signed-off-by: Matthew Wilcox (Oracle) Signed-off-by: Vlastimil Babka Reviewed-by: Roman Gushchin --- mm/slub.c | 31 +++++++++++++++++-------------- 1 file changed, 17 insertions(+), 14 deletions(-) diff --git a/mm/slub.c b/mm/slub.c index 8b82188849ae..a45b74d2712f 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -3532,7 +3532,7 @@ void kmem_cache_free(struct kmem_cache *s, void *x) EXPORT_SYMBOL(kmem_cache_free); struct detached_freelist { - struct page *page; + struct slab *slab; void *tail; void *freelist; int cnt; @@ -3554,8 +3554,8 @@ static inline void free_nonslab_page(struct page *page, void *object) /* * This function progressively scans the array with free objects (with * a limited look ahead) and extract objects belonging to the same - * page. It builds a detached freelist directly within the given - * page/objects. This can happen without any need for + * slab. It builds a detached freelist directly within the given + * slab/objects. This can happen without any need for * synchronization, because the objects are owned by running process. * The freelist is build up as a single linked list in the objects. * The idea is, that this detached freelist can then be bulk @@ -3570,10 +3570,11 @@ int build_detached_freelist(struct kmem_cache *s, size_t size, size_t first_skipped_index = 0; int lookahead = 3; void *object; - struct page *page; + struct folio *folio; + struct slab *slab; /* Always re-init detached_freelist */ - df->page = NULL; + df->slab = NULL; do { object = p[--size]; @@ -3583,17 +3584,19 @@ int build_detached_freelist(struct kmem_cache *s, size_t size, if (!object) return 0; - page = virt_to_head_page(object); + folio = virt_to_folio(object); if (!s) { /* Handle kalloc'ed objects */ - if (unlikely(!PageSlab(page))) { - free_nonslab_page(page, object); + if (unlikely(!folio_test_slab(folio))) { + free_nonslab_page(folio_page(folio, 0), object); p[size] = NULL; /* mark object processed */ return size; } /* Derive kmem_cache from object */ - df->s = page->slab_cache; + slab = folio_slab(folio); + df->s = slab->slab_cache; } else { + slab = folio_slab(folio); df->s = cache_from_obj(s, object); /* Support for memcg */ } @@ -3605,7 +3608,7 @@ int build_detached_freelist(struct kmem_cache *s, size_t size, } /* Start new detached freelist */ - df->page = page; + df->slab = slab; set_freepointer(df->s, object, NULL); df->tail = object; df->freelist = object; @@ -3617,8 +3620,8 @@ int build_detached_freelist(struct kmem_cache *s, size_t size, if (!object) continue; /* Skip processed objects */ - /* df->page is always set at this point */ - if (df->page == virt_to_head_page(object)) { + /* df->slab is always set at this point */ + if (df->slab == virt_to_slab(object)) { /* Opportunity build freelist */ set_freepointer(df->s, object, df->freelist); df->freelist = object; @@ -3650,10 +3653,10 @@ void kmem_cache_free_bulk(struct kmem_cache *s, size_t size, void **p) struct detached_freelist df; size = build_detached_freelist(s, size, p, &df); - if (!df.page) + if (!df.slab) continue; - slab_free(df.s, df.page, df.freelist, df.tail, df.cnt, _RET_IP_); + slab_free(df.s, slab_page(df.slab), df.freelist, df.tail, df.cnt, _RET_IP_); } while (likely(size)); } EXPORT_SYMBOL(kmem_cache_free_bulk);