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-rw-r--r--include/linux/mm.h3
-rw-r--r--mm/memory.c41
-rw-r--r--mm/truncate.c43
3 files changed, 63 insertions, 24 deletions
diff --git a/include/linux/mm.h b/include/linux/mm.h
index c274f75efcf9..8ae31622deef 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1719,6 +1719,7 @@ struct zap_details {
struct address_space *check_mapping; /* Check page->mapping if set */
pgoff_t first_index; /* Lowest page->index to unmap */
pgoff_t last_index; /* Highest page->index to unmap */
+ struct page *single_page; /* Locked page to be unmapped */
};
struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr,
@@ -1766,6 +1767,7 @@ extern vm_fault_t handle_mm_fault(struct vm_area_struct *vma,
extern int fixup_user_fault(struct mm_struct *mm,
unsigned long address, unsigned int fault_flags,
bool *unlocked);
+void unmap_mapping_page(struct page *page);
void unmap_mapping_pages(struct address_space *mapping,
pgoff_t start, pgoff_t nr, bool even_cows);
void unmap_mapping_range(struct address_space *mapping,
@@ -1786,6 +1788,7 @@ static inline int fixup_user_fault(struct mm_struct *mm, unsigned long address,
BUG();
return -EFAULT;
}
+static inline void unmap_mapping_page(struct page *page) { }
static inline void unmap_mapping_pages(struct address_space *mapping,
pgoff_t start, pgoff_t nr, bool even_cows) { }
static inline void unmap_mapping_range(struct address_space *mapping,
diff --git a/mm/memory.c b/mm/memory.c
index f3ffab9b9e39..486f4a2874e7 100644
--- 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
@@ -3237,6 +3248,36 @@ 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.
* @start: Index of first page to be unmapped.
diff --git a/mm/truncate.c b/mm/truncate.c
index 95af244b112a..234ddd879caa 100644
--- a/mm/truncate.c
+++ b/mm/truncate.c
@@ -167,13 +167,10 @@ void do_invalidatepage(struct page *page, unsigned int offset,
* its lock, b) when a concurrent invalidate_mapping_pages got there first and
* c) when tmpfs swizzles a page between a tmpfs inode and swapper_space.
*/
-static void
-truncate_cleanup_page(struct address_space *mapping, struct page *page)
+static void truncate_cleanup_page(struct page *page)
{
- if (page_mapped(page)) {
- unsigned int nr = thp_nr_pages(page);
- unmap_mapping_pages(mapping, page->index, nr, false);
- }
+ if (page_mapped(page))
+ unmap_mapping_page(page);
if (page_has_private(page))
do_invalidatepage(page, 0, thp_size(page));
@@ -218,7 +215,7 @@ int truncate_inode_page(struct address_space *mapping, struct page *page)
if (page->mapping != mapping)
return -EIO;
- truncate_cleanup_page(mapping, page);
+ truncate_cleanup_page(page);
delete_from_page_cache(page);
return 0;
}
@@ -325,7 +322,7 @@ void truncate_inode_pages_range(struct address_space *mapping,
index = indices[pagevec_count(&pvec) - 1] + 1;
truncate_exceptional_pvec_entries(mapping, &pvec, indices);
for (i = 0; i < pagevec_count(&pvec); i++)
- truncate_cleanup_page(mapping, pvec.pages[i]);
+ truncate_cleanup_page(pvec.pages[i]);
delete_from_page_cache_batch(mapping, &pvec);
for (i = 0; i < pagevec_count(&pvec); i++)
unlock_page(pvec.pages[i]);
@@ -639,6 +636,16 @@ int invalidate_inode_pages2_range(struct address_space *mapping,
continue;
}
+ if (!did_range_unmap && page_mapped(page)) {
+ /*
+ * If page is mapped, before taking its lock,
+ * zap the rest of the file in one hit.
+ */
+ unmap_mapping_pages(mapping, index,
+ (1 + end - index), false);
+ did_range_unmap = 1;
+ }
+
lock_page(page);
WARN_ON(page_to_index(page) != index);
if (page->mapping != mapping) {
@@ -646,23 +653,11 @@ int invalidate_inode_pages2_range(struct address_space *mapping,
continue;
}
wait_on_page_writeback(page);
- if (page_mapped(page)) {
- if (!did_range_unmap) {
- /*
- * Zap the rest of the file in one hit.
- */
- unmap_mapping_pages(mapping, index,
- (1 + end - index), false);
- did_range_unmap = 1;
- } else {
- /*
- * Just zap this page
- */
- unmap_mapping_pages(mapping, index,
- 1, false);
- }
- }
+
+ if (page_mapped(page))
+ unmap_mapping_page(page);
BUG_ON(page_mapped(page));
+
ret2 = do_launder_page(mapping, page);
if (ret2 == 0) {
if (!invalidate_complete_page2(mapping, page))