Merge remote-tracking branch 'torvalds/master' into perf/core

[linux-2.6-microblaze.git] / mm / memory.c

diff --git a/mm/memory.c b/mm/memory.c
index f3ffab9..486f4a2 100644 (file)
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1361,7 +1361,18 @@ static inline unsigned long zap_pmd_range(struct mmu_gather *tlb,
                        else if (zap_huge_pmd(tlb, vma, pmd, addr))
                                goto next;
                        /* fall through */
+               } else if (details && details->single_page &&
+                          PageTransCompound(details->single_page) &&
+                          next - addr == HPAGE_PMD_SIZE && pmd_none(*pmd)) {
+                       spinlock_t *ptl = pmd_lock(tlb->mm, pmd);
+                       /*
+                        * Take and drop THP pmd lock so that we cannot return
+                        * prematurely, while zap_huge_pmd() has cleared *pmd,
+                        * but not yet decremented compound_mapcount().
+                        */
+                       spin_unlock(ptl);
                }
+
                /*
                 * Here there can be other concurrent MADV_DONTNEED or
                 * trans huge page faults running, and if the pmd is
@@ -3236,6 +3247,36 @@ static inline void unmap_mapping_range_tree(struct rb_root_cached *root,
        }
 }
 
+/**
+ * unmap_mapping_page() - Unmap single page from processes.
+ * @page: The locked page to be unmapped.
+ *
+ * Unmap this page from any userspace process which still has it mmaped.
+ * Typically, for efficiency, the range of nearby pages has already been
+ * unmapped by unmap_mapping_pages() or unmap_mapping_range().  But once
+ * truncation or invalidation holds the lock on a page, it may find that
+ * the page has been remapped again: and then uses unmap_mapping_page()
+ * to unmap it finally.
+ */
+void unmap_mapping_page(struct page *page)
+{
+       struct address_space *mapping = page->mapping;
+       struct zap_details details = { };
+
+       VM_BUG_ON(!PageLocked(page));
+       VM_BUG_ON(PageTail(page));
+
+       details.check_mapping = mapping;
+       details.first_index = page->index;
+       details.last_index = page->index + thp_nr_pages(page) - 1;
+       details.single_page = page;
+
+       i_mmap_lock_write(mapping);
+       if (unlikely(!RB_EMPTY_ROOT(&mapping->i_mmap.rb_root)))
+               unmap_mapping_range_tree(&mapping->i_mmap, &details);
+       i_mmap_unlock_write(mapping);
+}
+
 /**
  * unmap_mapping_pages() - Unmap pages from processes.
  * @mapping: The address space containing pages to be unmapped.