On Fri, Mar 15, 2024 at 12:09:29PM +0100, Vlastimil Babka wrote: > 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? Sure. > 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. Indeed, this was the only immediately clear user for_each_populated_zone_pgdat() which stood out, but I'll look more closely. I added this helper because in an RFC patch I had another use case: https://lkml.kernel.org/r/20240314005710.2964798-1-mcgrof@xxxxxxxxxx Granted this is just an RFC. So happy to drop this if we don't have other users Luis
