[2/5] mm: Move zone watermark accesses behind an accessor

Commit Message

Mel Gorman Oct. 31, 2018, 4:06 p.m. UTC

This is a preparation patch only, no functional change.

Signed-off-by: Mel Gorman <[e-mail]>
---
 include/linux/mmzone.h |  9 +++++----
 mm/compaction.c        |  2 +-
 mm/page_alloc.c        | 12 ++++++------
 3 files changed, 12 insertions(+), 11 deletions(-)

Patch

diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index d4b0c79d2924..854d6c188888 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -267,9 +267,10 @@  enum zone_watermarks {
 	NR_WMARK
 };
 
-#define min_wmark_pages(z) (z->watermark[WMARK_MIN])
-#define low_wmark_pages(z) (z->watermark[WMARK_LOW])
-#define high_wmark_pages(z) (z->watermark[WMARK_HIGH])
+#define min_wmark_pages(z) (z->_watermark[WMARK_MIN])
+#define low_wmark_pages(z) (z->_watermark[WMARK_LOW])
+#define high_wmark_pages(z) (z->_watermark[WMARK_HIGH])
+#define wmark_pages(z, i) (z->_watermark[i])
 
 struct per_cpu_pages {
 	int count;		/* number of pages in the list */
@@ -360,7 +361,7 @@  struct zone {
 	/* Read-mostly fields */
 
 	/* zone watermarks, access with *_wmark_pages(zone) macros */
-	unsigned long watermark[NR_WMARK];
+	unsigned long _watermark[NR_WMARK];
 
 	unsigned long nr_reserved_highatomic;
 
diff --git a/mm/compaction.c b/mm/compaction.c
index faca45ebe62d..aa9473a64915 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -1430,7 +1430,7 @@  static enum compact_result __compaction_suitable(struct zone *zone, int order,
 	if (is_via_compact_memory(order))
 		return COMPACT_CONTINUE;
 
-	watermark = zone->watermark[alloc_flags & ALLOC_WMARK_MASK];
+	watermark = wmark_pages(zone, alloc_flags & ALLOC_WMARK_MASK);
 	/*
 	 * If watermarks for high-order allocation are already met, there
 	 * should be no need for compaction at all.
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index db5d61868c96..a51887765abc 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -3360,7 +3360,7 @@  get_page_from_freelist(gfp_t gfp_mask, unsigned int order, int alloc_flags,
 			}
 		}
 
-		mark = zone->watermark[alloc_flags & ALLOC_WMARK_MASK];
+		mark = wmark_pages(zone, alloc_flags & ALLOC_WMARK_MASK);
 		if (!zone_watermark_fast(zone, order, mark,
 				       ac_classzone_idx(ac), alloc_flags)) {
 			int ret;
@@ -4787,7 +4787,7 @@  long si_mem_available(void)
 		pages[lru] = global_node_page_state(NR_LRU_BASE + lru);
 
 	for_each_zone(zone)
-		wmark_low += zone->watermark[WMARK_LOW];
+		wmark_low += low_wmark_pages(zone);
 
 	/*
 	 * Estimate the amount of memory available for userspace allocations,
@@ -7323,13 +7323,13 @@  static void __setup_per_zone_wmarks(void)
 
 			min_pages = zone->managed_pages / 1024;
 			min_pages = clamp(min_pages, SWAP_CLUSTER_MAX, 128UL);
-			zone->watermark[WMARK_MIN] = min_pages;
+			zone->_watermark[WMARK_MIN] = min_pages;
 		} else {
 			/*
 			 * If it's a lowmem zone, reserve a number of pages
 			 * proportionate to the zone's size.
 			 */
-			zone->watermark[WMARK_MIN] = tmp;
+			zone->_watermark[WMARK_MIN] = tmp;
 		}
 
 		/*
@@ -7341,8 +7341,8 @@  static void __setup_per_zone_wmarks(void)
 			    mult_frac(zone->managed_pages,
 				      watermark_scale_factor, 10000));
 
-		zone->watermark[WMARK_LOW]  = min_wmark_pages(zone) + tmp;
-		zone->watermark[WMARK_HIGH] = min_wmark_pages(zone) + tmp * 2;
+		zone->_watermark[WMARK_LOW]  = min_wmark_pages(zone) + tmp;
+		zone->_watermark[WMARK_HIGH] = min_wmark_pages(zone) + tmp * 2;
 
 		spin_unlock_irqrestore(&zone->lock, flags);
 	}