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Commit b065b432 authored by Hugh Dickins's avatar Hugh Dickins Committed by Linus Torvalds
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shmem: cleanup shmem_add_to_page_cache 



shmem_add_to_page_cache() has three callsites, but only one of them wants
the radix_tree_preload() (an exceptional entry guarantees that the radix
tree node is present in the other cases), and only that site can achieve
mem_cgroup_uncharge_cache_page() (PageSwapCache makes it a no-op in the
other cases).  We did it this way originally to reflect
add_to_page_cache_locked(); but it's confusing now, so move the radix_tree
preloading and mem_cgroup uncharging to that one caller.

Signed-off-by: default avatarHugh Dickins <hughd@google.com>
Acked-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Michal Hocko <mhocko@suse.cz>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent d1899228

mm/shmem.c

+28 −30
Original line number Diff line number Diff line
@@ -288,25 +288,21 @@ static int shmem_add_to_page_cache(struct page *page, 
				   struct address_space *mapping,

				   pgoff_t index, gfp_t gfp, void *expected)

{

	int error = 0;

	int error;



	VM_BUG_ON(!PageLocked(page));

	VM_BUG_ON(!PageSwapBacked(page));



	if (!expected)

		error = radix_tree_preload(gfp & GFP_RECLAIM_MASK);

	if (!error) {

	page_cache_get(page);

	page->mapping = mapping;

	page->index = index;



	spin_lock_irq(&mapping->tree_lock);

	if (!expected)

			error = radix_tree_insert(&mapping->page_tree,

							index, page);

		error = radix_tree_insert(&mapping->page_tree, index, page);

	else

			error = shmem_radix_tree_replace(mapping, index,

							expected, page);

		error = shmem_radix_tree_replace(mapping, index, expected,

								 page);

	if (!error) {

		mapping->nrpages++;

		__inc_zone_page_state(page, NR_FILE_PAGES);
@@ -317,11 +313,6 @@ static int shmem_add_to_page_cache(struct page *page, 
		spin_unlock_irq(&mapping->tree_lock);

		page_cache_release(page);

	}

		if (!expected)

			radix_tree_preload_end();

	}

	if (error)

		mem_cgroup_uncharge_cache_page(page);

	return error;

}
@@ -1202,11 +1193,18 @@ static int shmem_getpage_gfp(struct inode *inode, pgoff_t index, 
		__set_page_locked(page);

		error = mem_cgroup_cache_charge(page, current->mm,

						gfp & GFP_RECLAIM_MASK);

		if (!error)

		if (error)

			goto decused;

		error = radix_tree_preload(gfp & GFP_RECLAIM_MASK);

		if (!error) {

			error = shmem_add_to_page_cache(page, mapping, index,

							gfp, NULL);

		if (error)

			radix_tree_preload_end();

		}

		if (error) {

			mem_cgroup_uncharge_cache_page(page);

			goto decused;

		}

		lru_cache_add_anon(page);



		spin_lock(&info->lock);