From 0f66114893997f781029c109b0974b7f61130df7 Mon Sep 17 00:00:00 2001 From: Mel Gorman Date: Thu, 28 Jul 2016 15:45:34 -0700 Subject: [PATCH] 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 Cc: Hillf Danton Acked-by: Johannes Weiner Cc: Joonsoo Kim Cc: Michal Hocko Cc: Minchan Kim Cc: Rik van Riel Cc: Vlastimil Babka Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/mmzone.h | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index d4f5cac0a8c3..edafdaf62e90 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -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