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>

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 159e6c7..be4dfe8 100644 (file)
--- 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:
        /*