mm: remove lru type checks from __isolate_lru_page()

After patch "mm: forbid lumpy-reclaim in shrink_active_list()" we can
completely remove anon/file and active/inactive lru type filters from
__isolate_lru_page(), because isolation for 0-order reclaim always
isolates pages from right lru list.  And pages-isolation for lumpy
shrink_inactive_list() or memory-compaction anyway allowed to isolate
pages from all evictable lru lists.

Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Hugh Dickins <hughd@google.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Glauber Costa <glommer@parallels.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/vmscan.c

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 987be81..27ef576 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -949,29 +949,14 @@
  *
  * returns 0 on success, -ve errno on failure.
  */
-int __isolate_lru_page(struct page *page, isolate_mode_t mode, int file)
+int __isolate_lru_page(struct page *page, isolate_mode_t mode)
 {
-	bool all_lru_mode;
 	int ret = -EINVAL;
 
 	/* Only take pages on the LRU. */
 	if (!PageLRU(page))
 		return ret;
 
-	all_lru_mode = (mode & (ISOLATE_ACTIVE|ISOLATE_INACTIVE)) ==
-		(ISOLATE_ACTIVE|ISOLATE_INACTIVE);
-
-	/*
-	 * When checking the active state, we need to be sure we are
-	 * dealing with comparible boolean values.  Take the logical not
-	 * of each.
-	 */
-	if (!all_lru_mode && !PageActive(page) != !(mode & ISOLATE_ACTIVE))
-		return ret;
-
-	if (!all_lru_mode && !!page_is_file_cache(page) != file)
-		return ret;
-
 	/* Do not give back unevictable pages for compaction */
 	if (PageUnevictable(page))
 		return ret;
@@ -1070,7 +1055,7 @@
 
 		VM_BUG_ON(!PageLRU(page));
 
-		switch (__isolate_lru_page(page, mode, file)) {
+		switch (__isolate_lru_page(page, mode)) {
 		case 0:
 			mem_cgroup_lru_del(page);
 			list_move(&page->lru, dst);
@@ -1282,7 +1267,7 @@
 	unsigned long nr_file;
 	unsigned long nr_dirty = 0;
 	unsigned long nr_writeback = 0;
-	isolate_mode_t isolate_mode = ISOLATE_INACTIVE;
+	isolate_mode_t isolate_mode = 0;
 	int file = is_file_lru(lru);
 	struct zone *zone = mz->zone;
 	struct zone_reclaim_stat *reclaim_stat = get_reclaim_stat(mz);
@@ -1452,7 +1437,7 @@
 	struct page *page;
 	struct zone_reclaim_stat *reclaim_stat = get_reclaim_stat(mz);
 	unsigned long nr_rotated = 0;
-	isolate_mode_t isolate_mode = ISOLATE_ACTIVE;
+	isolate_mode_t isolate_mode = 0;
 	int file = is_file_lru(lru);
 	struct zone *zone = mz->zone;