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

From: Mel Gorman
Date: Fri Nov 23 2018 - 06:45:54 EST


This is a preparation patch only, no functional change.

Signed-off-by: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Acked-by: Vlastimil Babka <vbabka@xxxxxxx>
---
include/linux/mmzone.h | 9 +++++----
mm/compaction.c | 2 +-
mm/page_alloc.c | 12 ++++++------
3 files changed, 12 insertions(+), 11 deletions(-)

diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 847705a6d0ec..e43e8e79db99 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -269,9 +269,10 @@ 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 */
@@ -362,7 +363,7 @@ 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 7c607479de4a..ef29490b0f46 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -1431,7 +1431,7 @@ 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 f86638aee96a..4ba84cd2977a 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -3376,7 +3376,7 @@ 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;
@@ -4796,7 +4796,7 @@ 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,
@@ -7422,13 +7422,13 @@ 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;
}

/*
@@ -7440,8 +7440,8 @@ 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);
}
--
2.16.4