[PATCH] mm: slab less atomics

[sfrench/cifs-2.6.git] / include / linux / mmzone.h

diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 34cbefd2ebded8437ab2cb82d6613264593df9a5..ebfc238cc243482d9baa9b7bb3bd92391d4f6479 100644 (file)
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -91,10 +91,21 @@ struct per_cpu_pageset {
  * be 8 (2 ** 3) zonelists.  GFP_ZONETYPES defines the number of possible
  * combinations of zone modifiers in "zone modifier space".
  *
+ * As an optimisation any zone modifier bits which are only valid when
+ * no other zone modifier bits are set (loners) should be placed in
+ * the highest order bits of this field.  This allows us to reduce the
+ * extent of the zonelists thus saving space.  For example in the case
+ * of three zone modifier bits, we could require up to eight zonelists.
+ * If the left most zone modifier is a "loner" then the highest valid
+ * zonelist would be four allowing us to allocate only five zonelists.
+ * Use the first form for GFP_ZONETYPES when the left most bit is not
+ * a "loner", otherwise use the second.
+ *
  * NOTE! Make sure this matches the zones in <linux/gfp.h>
  */
 #define GFP_ZONEMASK   0x07
-#define GFP_ZONETYPES  5
+/* #define GFP_ZONETYPES       (GFP_ZONEMASK + 1) */           /* Non-loner */
+#define GFP_ZONETYPES  ((GFP_ZONEMASK + 1) / 2 + 1)            /* Loner */
 
 /*
  * On machines where it is needed (eg PCs) we divide physical memory
@@ -149,14 +160,16 @@ struct zone {
        unsigned long           pages_scanned;     /* since last reclaim */
        int                     all_unreclaimable; /* All pages pinned */
 
-       /*
-        * Does the allocator try to reclaim pages from the zone as soon
-        * as it fails a watermark_ok() in __alloc_pages?
-        */
-       int                     reclaim_pages;
        /* A count of how many reclaimers are scanning this zone */
        atomic_t                reclaim_in_progress;
 
+       /*
+        * timestamp (in jiffies) of the last zone reclaim that did not
+        * result in freeing of pages. This is used to avoid repeated scans
+        * if all memory in the zone is in use.
+        */
+       unsigned long           last_unsuccessful_zone_reclaim;
+
        /*
         * prev_priority holds the scanning priority for this zone.  It is
         * defined as the scanning priority at which we achieved our reclaim