On Wed, Feb 5, 2025 at 5:27 PM Baoquan He <bhe@xxxxxxxxxx> wrote: > > Since ci->lock has been taken when isolating cluster from > si->free_clusters or taking si->percpu_cluster->next[order], > it's unnecessary to scan and check the cluster range availability > if i'ts empty cluster, and this can accelerate the huge page > swapping. > > Signed-off-by: Baoquan He <bhe@xxxxxxxxxx> > --- > mm/swapfile.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/mm/swapfile.c b/mm/swapfile.c > index 9c9a4ec6d4c6..61efde853eea 100644 > --- a/mm/swapfile.c > +++ b/mm/swapfile.c > @@ -729,6 +729,9 @@ static bool cluster_scan_range(struct swap_info_struct *si, > unsigned long offset, end = start + nr_pages; > unsigned char *map = si->swap_map; > > + if (cluster_is_empty(ci)) > + return true; > + Hi Baoquan, Thanks for the series. Most commits are looking great, but this one is a bit questionable. cluster_scan_range is only called by alloc_swap_scan_cluster, and it already checks if the cluster has enough empty slots to use, so this might be redundant. It is possible that cluster_scan_range sees an empty cluster if the cluster lock was dropped for reclaiming HAS_CACHE, but the chance should be extremely low, that this might be a negative optimization.
