On Mon, May 11, 2020 at 2:11 PM Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote: > > On Sat, 9 May 2020 07:19:46 -0700 Shakeel Butt <shakeelb@xxxxxxxxxx> wrote: > > > Currently, THP are counted as single pages until they are split right > > before being swapped out. However, at that point the VM is already in > > the middle of reclaim, and adjusting the LRU balance then is useless. > > > > Always account THP by the number of basepages, and remove the fixup > > from the splitting path. > > Confused. What kernel is this applicable to? It is still applicable to the latest Linux kernel. Basically lruvec->reclaim_stat->recent_[scanned|rotated] counters are used as heuristic in get_scan_count() to measure how much file and anon LRUs should be scanned by the current reclaim. Previously huge pages are treated as single page while updating the recent_[scanned|rotated] counters in swap.c while vmscan.c correctly updates them as huge pages.
