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-rw-r--r--include/linux/mmzone.h25
1 files changed, 19 insertions, 6 deletions
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 34cbefd2ebde..ebfc238cc243 100644
--- 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
@@ -149,15 +160,17 @@ 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
* target at the previous try_to_free_pages() or balance_pgdat()
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