memory controller BUG_ON()

Move mem_controller_cache_charge() above radix_tree_preload().
radix_tree_preload() disables preemption, even though the gfp_mask passed
contains __GFP_WAIT, we cannot really do __GFP_WAIT allocations, thus we
hit a BUG_ON() in kmem_cache_alloc().

This patch moves mem_controller_cache_charge() to above radix_tree_preload()
for cache charging.

Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 6 insertions, 7 deletions

diff --git a/mm/filemap.c b/mm/filemap.c
index 63040d5e0ae2..35867ab72640 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -460,14 +460,12 @@ int filemap_write_and_wait_range(struct address_space *mapping,
 int add_to_page_cache(struct page *page, struct address_space *mapping,
                 pgoff_t offset, gfp_t gfp_mask)
 {
-        int error = radix_tree_preload(gfp_mask & ~__GFP_HIGHMEM);
+        int error = mem_cgroup_cache_charge(page, current->mm, gfp_mask);
+        if (error)
+                goto out;
 
+        error = radix_tree_preload(gfp_mask & ~__GFP_HIGHMEM);
         if (error == 0) {
-
-                error = mem_cgroup_cache_charge(page, current->mm, gfp_mask);
-                if (error)
-                        goto out;
-
                 write_lock_irq(&mapping->tree_lock);
                 error = radix_tree_insert(&mapping->page_tree, offset, page);
                 if (!error) {
@@ -482,7 +480,8 @@ int add_to_page_cache(struct page *page, struct address_space *mapping,
 
                 write_unlock_irq(&mapping->tree_lock);
                 radix_tree_preload_end();
-        }
+        } else
+                mem_cgroup_uncharge_page(page);
 out:
         return error;
 }