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Commit 8e65d24c authored by Christoph Lameter's avatar Christoph Lameter Committed by Linus Torvalds
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SLUB: Do not use page->mapping 



After moving the lockless_freelist to kmem_cache_cpu we no longer need
page->lockless_freelist. Restructure the use of the struct page fields in
such a way that we never touch the mapping field.

This is turn allows us to remove the special casing of SLUB when determining
the mapping of a page (needed for corner cases of virtual caches machines that
need to flush caches of processors mapping a page).

Signed-off-by: default avatarChristoph Lameter <clameter@sgi.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent dfb4f096

include/linux/mm.h

+0 −4
Original line number Diff line number Diff line
@@ -568,10 +568,6 @@ static inline struct address_space *page_mapping(struct page *page) 
	VM_BUG_ON(PageSlab(page));

	if (unlikely(PageSwapCache(page)))

		mapping = &swapper_space;

#ifdef CONFIG_SLUB

	else if (unlikely(PageSlab(page)))

		mapping = NULL;

#endif

	else if (unlikely((unsigned long)mapping & PAGE_MAPPING_ANON))

		mapping = NULL;

	return mapping;

include/linux/mm_types.h

+2 −7
Original line number Diff line number Diff line
@@ -62,13 +62,8 @@ struct page { 
#if NR_CPUS >= CONFIG_SPLIT_PTLOCK_CPUS

	    spinlock_t ptl;

#endif

	    struct {			/* SLUB uses */

	    	void **lockless_freelist;

		struct kmem_cache *slab;	/* Pointer to slab */

	    };

	    struct {

		struct page *first_page;	/* Compound pages */

	    };

	    struct kmem_cache *slab;	/* SLUB: Pointer to slab */

	    struct page *first_page;	/* Compound tail pages */

	};

	union {

		pgoff_t index;		/* Our offset within mapping. */

mm/slub.c

+0 −2
Original line number Diff line number Diff line
@@ -1127,7 +1127,6 @@ static struct page *new_slab(struct kmem_cache *s, gfp_t flags, int node) 
	set_freepointer(s, last, NULL);



	page->freelist = start;

	page->lockless_freelist = NULL;

	page->inuse = 0;

out:

	if (flags & __GFP_WAIT)
@@ -1153,7 +1152,6 @@ static void __free_slab(struct kmem_cache *s, struct page *page) 
		NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE,

		- pages);



	page->mapping = NULL;

	__free_pages(page, s->order);

}