On Tue 23-07-19 04:08:15, Yafang Shao wrote:
> This is the follow-up of the
> commit "mm/compaction.c: clear total_{migrate,free}_scanned before scanning a new zone".
>
> These counters are used to track activities during compacting a zone,
> and they will be set to zero before compacting a new zone in all compact
> paths. Move all these common settings into compact_zone() for better
> management. A new helper compact_zone_counters_init() is introduced for
> this purpose.
The helper seems excessive a bit because we have a single call site but
other than that this is an improvement to the current fragile and
duplicated code.
I would just get rid of the helper and squash it to your previous patch
which Andrew already took to the mm tree.
> Signed-off-by: Yafang Shao <laoar.shao@xxxxxxxxx>
> Cc: Michal Hocko <mhocko@xxxxxxxx>
> Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
> Cc: Yafang Shao <shaoyafang@xxxxxxxxxxxxxx>
> ---
> mm/compaction.c | 28 ++++++++++++++--------------
> 1 file changed, 14 insertions(+), 14 deletions(-)
>
> diff --git a/mm/compaction.c b/mm/compaction.c
> index a109b45..356348b 100644
> --- a/mm/compaction.c
> +++ b/mm/compaction.c
> @@ -2065,6 +2065,19 @@ bool compaction_zonelist_suitable(struct alloc_context *ac, int order,
> return false;
> }
>
> +
> +/*
> + * Bellow counters are used to track activities during compacting a zone.
> + * Before compacting a new zone, we should init these counters first.
> + */
> +static void compact_zone_counters_init(struct compact_control *cc)
> +{
> + cc->total_migrate_scanned = 0;
> + cc->total_free_scanned = 0;
> + cc->nr_migratepages = 0;
> + cc->nr_freepages = 0;
> +}
> +
> static enum compact_result
> compact_zone(struct compact_control *cc, struct capture_control *capc)
> {
> @@ -2075,6 +2088,7 @@ bool compaction_zonelist_suitable(struct alloc_context *ac, int order,
> const bool sync = cc->mode != MIGRATE_ASYNC;
> bool update_cached;
>
> + compact_zone_counters_init(cc);
> cc->migratetype = gfpflags_to_migratetype(cc->gfp_mask);
> ret = compaction_suitable(cc->zone, cc->order, cc->alloc_flags,
> cc->classzone_idx);
> @@ -2278,10 +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,
> @@ -2418,10 +2428,6 @@ static void compact_node(int nid)
> if (!populated_zone(zone))
> 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);
> @@ -2526,8 +2532,6 @@ 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,
> @@ -2551,10 +2555,6 @@ 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);
> --
> 1.8.3.1
--
Michal Hocko
SUSE Labs
