From d122019bf061cccc4583eb9ad40bf58c2fe517be Mon Sep 17 00:00:00 2001 From: "Matthew Wilcox (Oracle)" Date: Mon, 4 Oct 2021 14:45:51 +0100 Subject: mm: Split slab into its own type Make struct slab independent of struct page. It still uses the underlying memory in struct page for storing slab-specific data, but slab and slub can now be weaned off using struct page directly. Some of the wrapper functions (slab_address() and slab_order()) still need to cast to struct folio, but this is a significant disentanglement. [ vbabka@suse.cz: Rebase on folios, use folio instead of page where possible. Do not duplicate flags field in struct slab, instead make the related accessors go through slab_folio(). For testing pfmemalloc use the folio_*_active flag accessors directly so the PageSlabPfmemalloc wrappers can be removed later. Make folio_slab() expect only folio_test_slab() == true folios and virt_to_slab() return NULL when folio_test_slab() == false. Move struct slab to mm/slab.h. Don't represent with struct slab pages that are not true slab pages, but just a compound page obtained directly rom page allocator (with large kmalloc() for SLUB and SLOB). ] Signed-off-by: Matthew Wilcox (Oracle) Signed-off-by: Vlastimil Babka Acked-by: Johannes Weiner Reviewed-by: Roman Gushchin --- include/linux/mm_types.h | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) (limited to 'include/linux/mm_types.h') diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index c3a6e6209600..1ae3537c7920 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -56,11 +56,11 @@ struct mem_cgroup; * in each subpage, but you may need to restore some of their values * afterwards. * - * SLUB uses cmpxchg_double() to atomically update its freelist and - * counters. That requires that freelist & counters be adjacent and - * double-word aligned. We align all struct pages to double-word - * boundaries, and ensure that 'freelist' is aligned within the - * struct. + * SLUB uses cmpxchg_double() to atomically update its freelist and counters. + * That requires that freelist & counters in struct slab be adjacent and + * double-word aligned. Because struct slab currently just reinterprets the + * bits of struct page, we align all struct pages to double-word boundaries, + * and ensure that 'freelist' is aligned within struct slab. */ #ifdef CONFIG_HAVE_ALIGNED_STRUCT_PAGE #define _struct_page_alignment __aligned(2 * sizeof(unsigned long)) -- cgit v1.2.3-59-g8ed1b