per-zone and reclaim enhancements for memory controller: add scan_global_lru macro

This is used to detect which scan_control scans global lru or mem_cgroup lru.
And compiled to be static value (1) when memory controller is not configured.
This may make the meaning obvious.

Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Herbert Poetzl <herbert@13thfloor.at>
Cc: Kirill Korotaev <dev@sw.ru>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Paul Menage <menage@google.com>
Cc: Pavel Emelianov <xemul@openvz.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 12 insertions, 5 deletions

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 159e6c760d83..be4dfe87be03 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -126,6 +126,12 @@ long vm_total_pages;	/* The total number of pages which the VM controls */
 static LIST_HEAD(shrinker_list);
 static DECLARE_RWSEM(shrinker_rwsem);
 
+#ifdef CONFIG_CGROUP_MEM_CONT
+#define scan_global_lru(sc)     (!(sc)->mem_cgroup)
+#else
+#define scan_global_lru(sc)     (1)
+#endif
+
 /*
  * Add a shrinker callback to be called from the vm
  */
@@ -1280,11 +1286,12 @@ static unsigned long do_try_to_free_pages(struct zone **zones, gfp_t gfp_mask,
                  * Don't shrink slabs when reclaiming memory from
                  * over limit cgroups
                  */
-                if (sc->mem_cgroup == NULL)
+                if (scan_global_lru(sc)) {
                         shrink_slab(sc->nr_scanned, gfp_mask, lru_pages);
-                if (reclaim_state) {
-                        nr_reclaimed += reclaim_state->reclaimed_slab;
-                        reclaim_state->reclaimed_slab = 0;
+                        if (reclaim_state) {
+                                nr_reclaimed += reclaim_state->reclaimed_slab;
+                                reclaim_state->reclaimed_slab = 0;
+                        }
                 }
                 total_scanned += sc->nr_scanned;
                 if (nr_reclaimed >= sc->swap_cluster_max) {
@@ -1311,7 +1318,7 @@ static unsigned long do_try_to_free_pages(struct zone **zones, gfp_t gfp_mask,
                         congestion_wait(WRITE, HZ/10);
         }
         /* top priority shrink_caches still had more to do? don't OOM, then */
-        if (!sc->all_unreclaimable && sc->mem_cgroup == NULL)
+        if (!sc->all_unreclaimable && scan_global_lru(sc))
                 ret = 1;
 out:
         /*