On Thu, Feb 08, 2024 at 12:49:19PM -0800, Andrew Morton wrote: > On Thu, 8 Feb 2024 15:26:06 +0900 Byungchul Park <byungchul@xxxxxx> wrote: > > > This is a preparation for migrc mechanism that frees folios at a better > > The term "migrc" appears in various places but I don't think we're told > what is actually means? > > > time later, rather than the moment migrating folios. The folios freed by > > migrc are too old to keep in pcp. > > How do we define "too old" and what causes you to believe this is the case? Migrc defers folio_put() for source folios of migration that would be unlikely used and frees a bunch of folios at once later. However, it pollutes pcp, which means fresher folios might get free_pcppages_bulk()ed and makes the effort to keep the best amount of pcp get unstable. So I didn't want to make this situation happen. Byungchul
