1 files changed, 36 insertions, 25 deletions

diff --git a/mm/filemap.c b/mm/filemap.c
index 731a2c24532d..1e6aec4a2d2e 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -467,32 +467,34 @@ int add_to_page_cache_locked(struct page *page, struct address_space *mapping,
 	error = mem_cgroup_cache_charge(page, current->mm,
 					gfp_mask & GFP_RECLAIM_MASK);
 	if (error)
-		goto out;
-
-	error = radix_tree_preload(gfp_mask & ~__GFP_HIGHMEM);
-	if (error == 0) {
-		page_cache_get(page);
-		page->mapping = mapping;
-		page->index = offset;
+		return error;
 
-		spin_lock_irq(&mapping->tree_lock);
-		error = radix_tree_insert(&mapping->page_tree, offset, page);
-		if (likely(!error)) {
-			mapping->nrpages++;
-			__inc_zone_page_state(page, NR_FILE_PAGES);
-			spin_unlock_irq(&mapping->tree_lock);
-			trace_mm_filemap_add_to_page_cache(page);
-		} else {
-			page->mapping = NULL;
-			/* Leave page->index set: truncation relies upon it */
-			spin_unlock_irq(&mapping->tree_lock);
-			mem_cgroup_uncharge_cache_page(page);
-			page_cache_release(page);
-		}
-		radix_tree_preload_end();
-	} else
+	error = radix_tree_maybe_preload(gfp_mask & ~__GFP_HIGHMEM);
+	if (error) {
 		mem_cgroup_uncharge_cache_page(page);
-out:
+		return error;
+	}
+
+	page_cache_get(page);
+	page->mapping = mapping;
+	page->index = offset;
+
+	spin_lock_irq(&mapping->tree_lock);
+	error = radix_tree_insert(&mapping->page_tree, offset, page);
+	radix_tree_preload_end();
+	if (unlikely(error))
+		goto err_insert;
+	mapping->nrpages++;
+	__inc_zone_page_state(page, NR_FILE_PAGES);
+	spin_unlock_irq(&mapping->tree_lock);
+	trace_mm_filemap_add_to_page_cache(page);
+	return 0;
+err_insert:
+	page->mapping = NULL;
+	/* Leave page->index set: truncation relies upon it */
+	spin_unlock_irq(&mapping->tree_lock);
+	mem_cgroup_uncharge_cache_page(page);
+	page_cache_release(page);
 	return error;
 }
 EXPORT_SYMBOL(add_to_page_cache_locked);
@@ -1614,6 +1616,7 @@ int filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 	struct inode *inode = mapping->host;
 	pgoff_t offset = vmf->pgoff;
 	struct page *page;
+	bool memcg_oom;
 	pgoff_t size;
 	int ret = 0;
 
@@ -1622,7 +1625,11 @@ int filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 		return VM_FAULT_SIGBUS;
 
 	/*
-	 * Do we have something in the page cache already?
+	 * Do we have something in the page cache already?  Either
+	 * way, try readahead, but disable the memcg OOM killer for it
+	 * as readahead is optional and no errors are propagated up
+	 * the fault stack.  The OOM killer is enabled while trying to
+	 * instantiate the faulting page individually below.
 	 */
 	page = find_get_page(mapping, offset);
 	if (likely(page) && !(vmf->flags & FAULT_FLAG_TRIED)) {
@@ -1630,10 +1637,14 @@ int filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 		 * We found the page, so try async readahead before
 		 * waiting for the lock.
 		 */
+		memcg_oom = mem_cgroup_toggle_oom(false);
 		do_async_mmap_readahead(vma, ra, file, page, offset);
+		mem_cgroup_toggle_oom(memcg_oom);
 	} else if (!page) {
 		/* No page in the page cache at all */
+		memcg_oom = mem_cgroup_toggle_oom(false);
 		do_sync_mmap_readahead(vma, ra, file, offset);
+		mem_cgroup_toggle_oom(memcg_oom);
 		count_vm_event(PGMAJFAULT);
 		mem_cgroup_count_vm_event(vma->vm_mm, PGMAJFAULT);
 		ret = VM_FAULT_MAJOR;