Re: [PATCH] mm/compaction: do not break pages whose order is larger than target order

Johannes Weiner
2025-04-25T15:32:35Z

On Fri, Apr 25, 2025 at 10:28:42PM +0800, Wenchao Hao wrote:
> On Fri, Apr 25, 2025 at 3:42 AM Johannes Weiner <hannes@cmpxchg.org> wrote:
> >
> > On Thu, Apr 24, 2025 at 11:38:15PM +0800, Wenchao Hao wrote:
> > > When scanning free pages for memory compaction, if the compaction target
> > > order is explicitly specified, do not split pages in buddy whose order
> > > are larger than compaction target order.
> >
> > Have you observed this to be an issue in practice?
> >
> > compact_finished() would have bailed if such a page had existed.
> >
>
> Yes, when proactive memory compaction is enabled, there may be situations
> where the order of isolated free pages is greater than the compaction
> requested order, and compact_finished() will return continue.

proactive compaction has an order of -1?