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Commit 3ac808fd authored by Kirill A. Shutemov's avatar Kirill A. Shutemov Committed by Linus Torvalds
Browse files

mm, thp: remove compound_lock() 



We are going to use migration entries to stabilize page counts.  It
means we don't need compound_lock() for that.

Signed-off-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Tested-by: default avatarSasha Levin <sasha.levin@oracle.com>
Tested-by: default avatarAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: default avatarVlastimil Babka <vbabka@suse.cz>
Acked-by: default avatarJerome Marchand <jmarchan@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Steve Capper <steve.capper@linaro.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent f765f540

include/linux/mm.h

+0 −35
Original line number Diff line number Diff line
@@ -410,41 +410,6 @@ static inline int is_vmalloc_or_module_addr(const void *x) 


extern void kvfree(const void *addr);



static inline void compound_lock(struct page *page)

{

#ifdef CONFIG_TRANSPARENT_HUGEPAGE

	VM_BUG_ON_PAGE(PageSlab(page), page);

	bit_spin_lock(PG_compound_lock, &page->flags);

#endif

}



static inline void compound_unlock(struct page *page)

{

#ifdef CONFIG_TRANSPARENT_HUGEPAGE

	VM_BUG_ON_PAGE(PageSlab(page), page);

	bit_spin_unlock(PG_compound_lock, &page->flags);

#endif

}



static inline unsigned long compound_lock_irqsave(struct page *page)

{

	unsigned long uninitialized_var(flags);

#ifdef CONFIG_TRANSPARENT_HUGEPAGE

	local_irq_save(flags);

	compound_lock(page);

#endif

	return flags;

}



static inline void compound_unlock_irqrestore(struct page *page,

					      unsigned long flags)

{

#ifdef CONFIG_TRANSPARENT_HUGEPAGE

	compound_unlock(page);

	local_irq_restore(flags);

#endif

}



/*

 * The atomic page->_mapcount, starts from -1: so that transitions

 * both from it and to it can be tracked, using atomic_inc_and_test

include/linux/page-flags.h

+1 −11
Original line number Diff line number Diff line
@@ -101,9 +101,6 @@ enum pageflags { 
#ifdef CONFIG_MEMORY_FAILURE

	PG_hwpoison,		/* hardware poisoned page. Don't touch */

#endif

#ifdef CONFIG_TRANSPARENT_HUGEPAGE

	PG_compound_lock,

#endif

#if defined(CONFIG_IDLE_PAGE_TRACKING) && defined(CONFIG_64BIT)

	PG_young,

	PG_idle,
@@ -613,12 +610,6 @@ static inline void ClearPageSlabPfmemalloc(struct page *page) 
#define __PG_MLOCKED		0

#endif



#ifdef CONFIG_TRANSPARENT_HUGEPAGE

#define __PG_COMPOUND_LOCK		(1 << PG_compound_lock)

#else

#define __PG_COMPOUND_LOCK		0

#endif



/*

 * Flags checked when a page is freed.  Pages being freed should not have

 * these flags set.  It they are, there is a problem.
@@ -628,8 +619,7 @@ static inline void ClearPageSlabPfmemalloc(struct page *page) 
	 1 << PG_private | 1 << PG_private_2 | \

	 1 << PG_writeback | 1 << PG_reserved | \

	 1 << PG_slab	 | 1 << PG_swapcache | 1 << PG_active | \

	 1 << PG_unevictable | __PG_MLOCKED | \

	 __PG_COMPOUND_LOCK)

	 1 << PG_unevictable | __PG_MLOCKED)



/*

 * Flags checked when a page is prepped for return by the page allocator.

mm/debug.c

+0 −3
Original line number Diff line number Diff line
@@ -40,9 +40,6 @@ static const struct trace_print_flags pageflag_names[] = { 
#ifdef CONFIG_MEMORY_FAILURE

	{1UL << PG_hwpoison,		"hwpoison"	},

#endif

#ifdef CONFIG_TRANSPARENT_HUGEPAGE

	{1UL << PG_compound_lock,	"compound_lock"	},

#endif

#if defined(CONFIG_IDLE_PAGE_TRACKING) && defined(CONFIG_64BIT)

	{1UL << PG_young,		"young"		},

	{1UL << PG_idle,		"idle"		},

mm/memcontrol.c

+3 −8
Original line number Diff line number Diff line
@@ -2433,9 +2433,7 @@ void __memcg_kmem_uncharge(struct page *page, int order) 


/*

 * Because tail pages are not marked as "used", set it. We're under

 * zone->lru_lock, 'splitting on pmd' and compound_lock.

 * charge/uncharge will be never happen and move_account() is done under

 * compound_lock(), so we don't have to take care of races.

 * zone->lru_lock and migration entries setup in all page mappings.

 */

void mem_cgroup_split_huge_fixup(struct page *head)

{
@@ -4507,9 +4505,7 @@ static struct page *mc_handle_file_pte(struct vm_area_struct *vma, 
 * @from: mem_cgroup which the page is moved from.

 * @to:	mem_cgroup which the page is moved to. @from != @to.

 *

 * The caller must confirm following.

 * - page is not on LRU (isolate_page() is useful.)

 * - compound_lock is held when nr_pages > 1

 * The caller must make sure the page is not on LRU (isolate_page() is useful.)

 *

 * This function doesn't do "charge" to new cgroup and doesn't do "uncharge"

 * from old cgroup.
@@ -4868,8 +4864,7 @@ static int mem_cgroup_move_charge_pte_range(pmd_t *pmd, 
	struct page *page;



	/*

	 * We don't take compound_lock() here but no race with splitting thp

	 * happens because:

	 * No race with splitting thp happens because:

	 *  - if pmd_trans_huge_lock() returns 1, the relevant thp is not

	 *    under splitting, which means there's no concurrent thp split,

	 *  - if another thread runs into split_huge_page() just after we