mm, compaction: rearrange compact_control

compact_control spans two cache lines with write-intensive lines on
both.  Rearrange so the most write-intensive fields are in the same
cache line.  This has a negligible impact on the overall performance of
compaction and is more a tidying exercise than anything.

Link: http://lkml.kernel.org/r/20190118175136.31341-3-mgorman@techsingularity.net
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: David Rientjes <rientjes@google.com>
Cc: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/internal.h b/mm/internal.h
index 5564841fce36a8d50d5efba4d29ed2e25be05b3b..867af5425432aa18046be374a8f9459e6431f132 100644 (file)
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -184,14 +184,14 @@ extern int user_min_free_kbytes;
 struct compact_control {
        struct list_head freepages;     /* List of free pages to migrate to */
        struct list_head migratepages;  /* List of pages being migrated */
-       struct zone *zone;
        unsigned int nr_freepages;      /* Number of isolated free pages */
        unsigned int nr_migratepages;   /* Number of pages to migrate */
-       unsigned long total_migrate_scanned;
-       unsigned long total_free_scanned;
        unsigned long free_pfn;         /* isolate_freepages search base */
        unsigned long migrate_pfn;      /* isolate_migratepages search base */
        unsigned long last_migrated_pfn;/* Not yet flushed page being freed */
+       struct zone *zone;
+       unsigned long total_migrate_scanned;
+       unsigned long total_free_scanned;
        const gfp_t gfp_mask;           /* gfp mask of a direct compactor */
        int order;                      /* order a direct compactor needs */
        int migratetype;                /* migratetype of direct compactor */