On 3/15/24 06:38, Luis Chamberlain wrote:
> On Thu, Mar 14, 2024 at 03:19:45PM +0800, Baolin Wang wrote:
>>
>>
>> On 2024/3/14 08:54, Luis Chamberlain wrote:
>> > We can just wrap most of the work done on fragmentation_score_node()
>> > into a pgdat helper for populated zones. Add the helper and use it.
>> >
>> > Signed-off-by: Luis Chamberlain <mcgrof@xxxxxxxxxx>
>> > ---
>> > include/linux/mmzone.h | 8 ++++++++
>> > mm/compaction.c | 9 ++-------
>> > 2 files changed, 10 insertions(+), 7 deletions(-)
>> >
>> > diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
>> > index a497f189d988..1fd74c7100ec 100644
>> > --- a/include/linux/mmzone.h
>> > +++ b/include/linux/mmzone.h
>> > @@ -1597,6 +1597,14 @@ extern struct zone *next_zone(struct zone *zone);
>> > ; /* do nothing */ \
>> > else
>> > +#define for_each_populated_zone_pgdat(zone, pgdat) \
>> > + for (zone = pgdat->node_zones; \
>> > + zone; \
>> > + zone = next_zone(zone)) \
>> > + if (!populated_zone(zone)) \
>> > + ; /* do nothing */ \
>> > + else
>>
>> I think this will break the original logics, since the next_zone() will
>> iterate over all memory zones, instead of only the memory zones of the
>> specified node.
>
> Definitely, thanks, so we'd need something like this in addition:
IMHO that's unnecessarily complex, why not just do the iteration all inline
without this next_zone_pgdat() helper?
Also maybe you could find more users if you created just a
for_each_zone_pgdat() and left the populated_zone() in the user? Otherwise
it's quite a specific helper with just one user.
> diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
> index 34b729fc751b..bd11d33ea14d 100644
> --- a/include/linux/mmzone.h
> +++ b/include/linux/mmzone.h
> @@ -1568,6 +1568,7 @@ static inline struct pglist_data *NODE_DATA(int nid)
> extern struct pglist_data *first_online_pgdat(void);
> extern struct pglist_data *next_online_pgdat(struct pglist_data *pgdat);
> extern struct zone *next_zone(struct zone *zone);
> +extern struct zone *next_zone_pgdat(struct zone *zone, struct pglist_data *pgdat);
>
> /**
> * for_each_online_pgdat - helper macro to iterate over all online nodes
> @@ -1600,7 +1601,7 @@ extern struct zone *next_zone(struct zone *zone);
> #define for_each_populated_zone_pgdat(zone, pgdat) \
> for (zone = pgdat->node_zones; \
> zone; \
> - zone = next_zone(zone)) \
> + zone = next_zone_pgdat(zone, pgdat)) \
> if (!populated_zone(zone)) \
> ; /* do nothing */ \
> else
> diff --git a/mm/compaction.c b/mm/compaction.c
> index 015126803017..96434f6fc1ad 100644
> --- a/mm/compaction.c
> +++ b/mm/compaction.c
> @@ -2152,7 +2152,6 @@ static unsigned int fragmentation_score_node(pg_data_t *pgdat)
> {
> unsigned int score = 0;
> struct zone *zone;
> - int zoneid;
>
> for_each_populated_zone_pgdat(zone, pgdat)
> score += fragmentation_score_zone_weighted(zone);
> diff --git a/mm/mmzone.c b/mm/mmzone.c
> index c01896eca736..043a6dc16c05 100644
> --- a/mm/mmzone.c
> +++ b/mm/mmzone.c
> @@ -43,6 +43,18 @@ struct zone *next_zone(struct zone *zone)
> return zone;
> }
>
> +/*
> + * next_zone_pgdat - helper magic for for_each_zone() per node
> + */
> +struct zone *next_zone_pgdat(struct zone *zone, struct pglist_data *pgdat)
> +{
> + if (!zone || !pgdat)
> + return NULL;
> + if (zone < pgdat->node_zones + MAX_NR_ZONES - 1)
> + return ++zone;
> + return NULL;
> +}
> +
> static inline int zref_in_nodemask(struct zoneref *zref, nodemask_t *nodes)
> {
> #ifdef CONFIG_NUMA
