Commit 8b2e9b71 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Revert "mm: create a separate slab for page->ptl allocation" 



This reverts commit ea1e7ed3.

Al points out that while the commit *does* actually create a separate
slab for the page->ptl allocation, that slab is never actually used, and
the code continues to use kmalloc/kfree.

Damien Wyart points out that the original patch did have the conversion
to use kmem_cache_alloc/free, so it got lost somewhere on its way to me.

Revert the half-arsed attempt that didn't do anything.  If we really do
want the special slab (remember: this is all relevant just for debug
builds, so it's not necessarily all that critical) we might as well redo
the patch fully.

Reported-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
Acked-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Cc: Kirill A Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent b5898cd0

include/linux/mm.h

+0 −9
Original line number Diff line number Diff line
@@ -1318,7 +1318,6 @@ static inline pmd_t *pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long a 


#if USE_SPLIT_PTE_PTLOCKS

#if BLOATED_SPINLOCKS

void __init ptlock_cache_init(void);

extern bool ptlock_alloc(struct page *page);

extern void ptlock_free(struct page *page);
@@ -1327,7 +1326,6 @@ static inline spinlock_t *ptlock_ptr(struct page *page) 
	return page->ptl;

}

#else /* BLOATED_SPINLOCKS */

static inline void ptlock_cache_init(void) {}

static inline bool ptlock_alloc(struct page *page)

{

	return true;
@@ -1380,17 +1378,10 @@ static inline spinlock_t *pte_lockptr(struct mm_struct *mm, pmd_t *pmd) 
{

	return &mm->page_table_lock;

}

static inline void ptlock_cache_init(void) {}

static inline bool ptlock_init(struct page *page) { return true; }

static inline void pte_lock_deinit(struct page *page) {}

#endif /* USE_SPLIT_PTE_PTLOCKS */



static inline void pgtable_init(void)

{

	ptlock_cache_init();

	pgtable_cache_init();

}



static inline bool pgtable_page_ctor(struct page *page)

{

	inc_zone_page_state(page, NR_PAGETABLE);

init/main.c

+1 −1
Original line number Diff line number Diff line
@@ -476,7 +476,7 @@ static void __init mm_init(void) 
	mem_init();

	kmem_cache_init();

	percpu_init_late();

	pgtable_init();

	pgtable_cache_init();

	vmalloc_init();

}

mm/memory.c

+0 −7
Original line number Diff line number Diff line
@@ -4272,13 +4272,6 @@ void copy_user_huge_page(struct page *dst, struct page *src, 
#endif /* CONFIG_TRANSPARENT_HUGEPAGE || CONFIG_HUGETLBFS */



#if USE_SPLIT_PTE_PTLOCKS && BLOATED_SPINLOCKS

static struct kmem_cache *page_ptl_cachep;

void __init ptlock_cache_init(void)

{

	page_ptl_cachep = kmem_cache_create("page->ptl", sizeof(spinlock_t), 0,

			SLAB_PANIC, NULL);

}



bool ptlock_alloc(struct page *page)

{

	spinlock_t *ptl;

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