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-rw-r--r--fs/fuse/dev.c10
-rw-r--r--include/linux/memcontrol.h4
-rw-r--r--include/linux/pagemap.h1
-rw-r--r--mm/filemap.c70
-rw-r--r--mm/memcontrol.c4
-rw-r--r--mm/migrate.c2
6 files changed, 80 insertions, 11 deletions
diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
index 213d3cf4f5e9..640fc229df10 100644
--- a/fs/fuse/dev.c
+++ b/fs/fuse/dev.c
@@ -737,14 +737,12 @@ static int fuse_try_move_page(struct fuse_copy_state *cs, struct page **pagep)
if (WARN_ON(PageMlocked(oldpage)))
goto out_fallback_unlock;
- remove_from_page_cache(oldpage);
- page_cache_release(oldpage);
-
- err = add_to_page_cache_locked(newpage, mapping, index, GFP_KERNEL);
+ err = replace_page_cache_page(oldpage, newpage, GFP_KERNEL);
if (err) {
- printk(KERN_WARNING "fuse_try_move_page: failed to add page");
- goto out_fallback_unlock;
+ unlock_page(newpage);
+ return err;
}
+
page_cache_get(newpage);
if (!(buf->flags & PIPE_BUF_FLAG_LRU))
diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index f512e189be5a..a1a1e5384f6e 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -96,7 +96,7 @@ extern struct cgroup_subsys_state *mem_cgroup_css(struct mem_cgroup *mem);
extern int
mem_cgroup_prepare_migration(struct page *page,
- struct page *newpage, struct mem_cgroup **ptr);
+ struct page *newpage, struct mem_cgroup **ptr, gfp_t gfp_mask);
extern void mem_cgroup_end_migration(struct mem_cgroup *mem,
struct page *oldpage, struct page *newpage, bool migration_ok);
@@ -249,7 +249,7 @@ static inline struct cgroup_subsys_state *mem_cgroup_css(struct mem_cgroup *mem)
static inline int
mem_cgroup_prepare_migration(struct page *page, struct page *newpage,
- struct mem_cgroup **ptr)
+ struct mem_cgroup **ptr, gfp_t gfp_mask)
{
return 0;
}
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index 9c66e994540f..26946ad483bf 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -457,6 +457,7 @@ int add_to_page_cache_lru(struct page *page, struct address_space *mapping,
pgoff_t index, gfp_t gfp_mask);
extern void remove_from_page_cache(struct page *page);
extern void __remove_from_page_cache(struct page *page);
+int replace_page_cache_page(struct page *old, struct page *new, gfp_t gfp_mask);
/*
* Like add_to_page_cache_locked, but used to add newly allocated pages:
diff --git a/mm/filemap.c b/mm/filemap.c
index 312b6eb78430..c1459f2cdb5e 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -387,6 +387,76 @@ int filemap_write_and_wait_range(struct address_space *mapping,
EXPORT_SYMBOL(filemap_write_and_wait_range);
/**
+ * replace_page_cache_page - replace a pagecache page with a new one
+ * @old: page to be replaced
+ * @new: page to replace with
+ * @gfp_mask: allocation mode
+ *
+ * This function replaces a page in the pagecache with a new one. On
+ * success it acquires the pagecache reference for the new page and
+ * drops it for the old page. Both the old and new pages must be
+ * locked. This function does not add the new page to the LRU, the
+ * caller must do that.
+ *
+ * The remove + add is atomic. The only way this function can fail is
+ * memory allocation failure.
+ */
+int replace_page_cache_page(struct page *old, struct page *new, gfp_t gfp_mask)
+{
+ int error;
+ struct mem_cgroup *memcg = NULL;
+
+ VM_BUG_ON(!PageLocked(old));
+ VM_BUG_ON(!PageLocked(new));
+ VM_BUG_ON(new->mapping);
+
+ /*
+ * This is not page migration, but prepare_migration and
+ * end_migration does enough work for charge replacement.
+ *
+ * In the longer term we probably want a specialized function
+ * for moving the charge from old to new in a more efficient
+ * manner.
+ */
+ error = mem_cgroup_prepare_migration(old, new, &memcg, gfp_mask);
+ if (error)
+ return error;
+
+ error = radix_tree_preload(gfp_mask & ~__GFP_HIGHMEM);
+ if (!error) {
+ struct address_space *mapping = old->mapping;
+ void (*freepage)(struct page *);
+
+ pgoff_t offset = old->index;
+ freepage = mapping->a_ops->freepage;
+
+ page_cache_get(new);
+ new->mapping = mapping;
+ new->index = offset;
+
+ spin_lock_irq(&mapping->tree_lock);
+ __remove_from_page_cache(old);
+ error = radix_tree_insert(&mapping->page_tree, offset, new);
+ BUG_ON(error);
+ mapping->nrpages++;
+ __inc_zone_page_state(new, NR_FILE_PAGES);
+ if (PageSwapBacked(new))
+ __inc_zone_page_state(new, NR_SHMEM);
+ spin_unlock_irq(&mapping->tree_lock);
+ radix_tree_preload_end();
+ if (freepage)
+ freepage(old);
+ page_cache_release(old);
+ mem_cgroup_end_migration(memcg, old, new, true);
+ } else {
+ mem_cgroup_end_migration(memcg, old, new, false);
+ }
+
+ return error;
+}
+EXPORT_SYMBOL_GPL(replace_page_cache_page);
+
+/**
* add_to_page_cache_locked - add a locked page to the pagecache
* @page: page to add
* @mapping: the page's address_space
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index da53a252b259..6ef5c53dffcb 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2883,7 +2883,7 @@ static inline int mem_cgroup_move_swap_account(swp_entry_t entry,
* page belongs to.
*/
int mem_cgroup_prepare_migration(struct page *page,
- struct page *newpage, struct mem_cgroup **ptr)
+ struct page *newpage, struct mem_cgroup **ptr, gfp_t gfp_mask)
{
struct page_cgroup *pc;
struct mem_cgroup *mem = NULL;
@@ -2940,7 +2940,7 @@ int mem_cgroup_prepare_migration(struct page *page,
return 0;
*ptr = mem;
- ret = __mem_cgroup_try_charge(NULL, GFP_KERNEL, ptr, false, PAGE_SIZE);
+ ret = __mem_cgroup_try_charge(NULL, gfp_mask, ptr, false, PAGE_SIZE);
css_put(&mem->css);/* drop extra refcnt */
if (ret || *ptr == NULL) {
if (PageAnon(page)) {
diff --git a/mm/migrate.c b/mm/migrate.c
index 352de555626c..8aacce3af8cd 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -678,7 +678,7 @@ static int unmap_and_move(new_page_t get_new_page, unsigned long private,
}
/* charge against new page */
- charge = mem_cgroup_prepare_migration(page, newpage, &mem);
+ charge = mem_cgroup_prepare_migration(page, newpage, &mem, GFP_KERNEL);
if (charge == -ENOMEM) {
rc = -ENOMEM;
goto unlock;