On Tue, Jul 23, 2019 at 4:12 PM Michal Hocko <mhocko@xxxxxxxx> wrote:
>
> 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.
>
Understood.
> I would just get rid of the helper and squash it to your previous patch
> which Andrew already took to the mm tree.
>
I appreciate it.
Thanks
Yafang
> > 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
