mm/compaction.c: clear total_{migrate,free}_scanned before scanning a new zone

total_{migrate,free}_scanned will be added to COMPACTMIGRATE_SCANNED and
COMPACTFREE_SCANNED in compact_zone().  We should clear them before
scanning a new zone.  In the proc triggered compaction, we forgot clearing
them.

[laoar.shao@gmail.com: introduce a helper compact_zone_counters_init()]
Link: http://lkml.kernel.org/r/1563869295-25748-1-git-send-email-laoar.shao@gmail.com
[akpm@linux-foundation.org: expand compact_zone_counters_init() into its single callsite, per mhocko]
[vbabka@suse.cz: squash compact_zone() list_head init as well]
Link: http://lkml.kernel.org/r/1fb6f7da-f776-9e42-22f8-bbb79b030b98@suse.cz
[akpm@linux-foundation.org: kcompactd_do_work(): avoid unnecessary initialization of cc.zone]
Link: http://lkml.kernel.org/r/1563789275-9639-1-git-send-email-laoar.shao@gmail.com
Fixes: 7f354a548d1c ("mm, compaction: add vmstats for kcompactd work")
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: David Rientjes <rientjes@google.com>
Cc: Yafang Shao <shaoyafang@didiglobal.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@suse.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/compaction.c b/mm/compaction.c
index 777c088e911398a628b9562b7e5dcf38729689e0..d99d59412c7555e38fe486ee609ceab8b163e00d 100644 (file)
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -2078,6 +2078,17 @@ compact_zone(struct compact_control *cc, struct capture_control *capc)
        const bool sync = cc->mode != MIGRATE_ASYNC;
        bool update_cached;
 
+       /*
+        * These counters track activities during zone compaction.  Initialize
+        * them before compacting a new zone.
+        */
+       cc->total_migrate_scanned = 0;
+       cc->total_free_scanned = 0;
+       cc->nr_migratepages = 0;
+       cc->nr_freepages = 0;
+       INIT_LIST_HEAD(&cc->freepages);
+       INIT_LIST_HEAD(&cc->migratepages);
+
        cc->migratetype = gfpflags_to_migratetype(cc->gfp_mask);
        ret = compaction_suitable(cc->zone, cc->order, cc->alloc_flags,
                                                        cc->classzone_idx);
@@ -2281,10 +2292,6 @@ static enum compact_result compact_zone_order(struct zone *zone, int order,
 {
        enum compact_result ret;
        struct compact_control cc = {
-               .nr_freepages = 0,
-               .nr_migratepages = 0,
-               .total_migrate_scanned = 0,
-               .total_free_scanned = 0,
                .order = order,
                .search_order = order,
                .gfp_mask = gfp_mask,
@@ -2305,8 +2312,6 @@ static enum compact_result compact_zone_order(struct zone *zone, int order,
 
        if (capture)
                current->capture_control = &capc;
-       INIT_LIST_HEAD(&cc.freepages);
-       INIT_LIST_HEAD(&cc.migratepages);
 
        ret = compact_zone(&cc, &capc);
 
@@ -2408,8 +2413,6 @@ static void compact_node(int nid)
        struct zone *zone;
        struct compact_control cc = {
                .order = -1,
-               .total_migrate_scanned = 0,
-               .total_free_scanned = 0,
                .mode = MIGRATE_SYNC,
                .ignore_skip_hint = true,
                .whole_zone = true,
@@ -2423,11 +2426,7 @@ static void compact_node(int nid)
                if (!populated_zone(zone))
                        continue;
 
-               cc.nr_freepages = 0;
-               cc.nr_migratepages = 0;
                cc.zone = zone;
-               INIT_LIST_HEAD(&cc.freepages);
-               INIT_LIST_HEAD(&cc.migratepages);
 
                compact_zone(&cc, NULL);
 
@@ -2529,8 +2528,6 @@ static void kcompactd_do_work(pg_data_t *pgdat)
        struct compact_control cc = {
                .order = pgdat->kcompactd_max_order,
                .search_order = pgdat->kcompactd_max_order,
-               .total_migrate_scanned = 0,
-               .total_free_scanned = 0,
                .classzone_idx = pgdat->kcompactd_classzone_idx,
                .mode = MIGRATE_SYNC_LIGHT,
                .ignore_skip_hint = false,
@@ -2554,16 +2551,10 @@ static void kcompactd_do_work(pg_data_t *pgdat)
                                                        COMPACT_CONTINUE)
                        continue;
 
-               cc.nr_freepages = 0;
-               cc.nr_migratepages = 0;
-               cc.total_migrate_scanned = 0;
-               cc.total_free_scanned = 0;
-               cc.zone = zone;
-               INIT_LIST_HEAD(&cc.freepages);
-               INIT_LIST_HEAD(&cc.migratepages);
-
                if (kthread_should_stop())
                        return;
+
+               cc.zone = zone;
                status = compact_zone(&cc, NULL);
 
                if (status == COMPACT_SUCCESS) {