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: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Tested-by: Sasha Levin <sasha.levin@oracle.com>
Tested-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Jerome 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: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 34387351930cecea8edd4a0173d822a5389e3305..70f59de2e28849a707f4f460c51951f797374ef4 100644 (file)
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -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

diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index 7bc7fd9c4c5ca8f53567b62733e24f2dff5831b2..0c42acca0338d7dff740850a76543cb8416c071d 100644 (file)
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -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.

diff --git a/mm/debug.c b/mm/debug.c
index 5d2072ed8d5e7c925877b0759163035a9a2a0fe0..03c9a13f9f6a264655b3a46371529de25021d3b2 100644 (file)
--- a/mm/debug.c
+++ b/mm/debug.c
@@ -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"          },

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 311fd2b71bae3beb85362997afa3dfe560aaf0f6..db2a5d9ad8863c56bd79676d1c2c03f0b972f222 100644 (file)
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -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