On 5/25/23 14:54, Baolin Wang wrote: > I've observed that fast isolation often isolates more pages than > cc->migratepages, and the excess freepages will be released back to the > buddy system. So skip fast freepages isolation if enough freepages are > isolated to save some CPU cycles. > > Signed-off-by: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx> Acked-by: Vlastimil Babka <vbabka@xxxxxxx> > --- > mm/compaction.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/mm/compaction.c b/mm/compaction.c > index eccec84dae82..3ade4c095ed2 100644 > --- a/mm/compaction.c > +++ b/mm/compaction.c > @@ -1550,6 +1550,10 @@ static void fast_isolate_freepages(struct compact_control *cc) > > spin_unlock_irqrestore(&cc->zone->lock, flags); > > + /* Skip fast search if enough freepages isolated */ > + if (cc->nr_freepages >= cc->nr_migratepages) > + break; > + > /* > * Smaller scan on next order so the total scan is related > * to freelist_scan_limit.
