From: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx> Subject: 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@xxxxxxxxxxxxxxxxxxx Signed-off-by: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx> Cc: Hillf Danton <hillf.zj@xxxxxxxxxxxxxxx> Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx> Cc: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxxxxx> Cc: Minchan Kim <minchan@xxxxxxxxxx> Cc: Rik van Riel <riel@xxxxxxxxxxx> Cc: Vlastimil Babka <vbabka@xxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- include/linux/mmzone.h | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff -puN include/linux/mmzone.h~mm-mmzone-clarify-the-usage-of-zone-padding include/linux/mmzone.h --- a/include/linux/mmzone.h~mm-mmzone-clarify-the-usage-of-zone-padding +++ a/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 _ -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
