mm, mmzone: clarify the usage of zone padding

Zone padding separates write-intensive fields used by page allocation,
compaction and vmstats but the comments are a little misleading and need
clarification.

Link: http://lkml.kernel.org/r/1467970510-21195-5-git-send-email-mgorman@techsingularity.net
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Mel Gorman 2016-07-28 15:45:34 -07:00 committed by Linus Torvalds
parent 599d0c954f
commit 0f66114893

View File

@ -477,20 +477,21 @@ struct zone {
unsigned long wait_table_hash_nr_entries;
unsigned long wait_table_bits;
/* Write-intensive fields used from the page allocator */
ZONE_PADDING(_pad1_)
/* free areas of different sizes */
struct free_area free_area[MAX_ORDER];
/* zone flags, see below */
unsigned long flags;
/* Write-intensive fields used from the page allocator */
/* Primarily protects free_area */
spinlock_t lock;
/* Write-intensive fields used by compaction and vmstats. */
ZONE_PADDING(_pad2_)
/* Write-intensive fields used by page reclaim */
/*
* When free pages are below this point, additional steps are taken
* when reading the number of free pages to avoid per-cpu counter