Jan Kara <jack@xxxxxxx> writes: > when rebasing our enterprise distro to a newer kernel (from 4.4 to 4.12) we > have noticed a regression in bonnie++ benchmark when deleting files. > Eventually we have tracked this down to a fact that page cache truncation got > slower by about 10%. There were both gains and losses in the above interval of > kernels but we have been able to identify that commit 83929372f629 "filemap: > prepare find and delete operations for huge pages" caused about 10% regression > on its own. It's odd that just checking if some pages are huge should be that expensive, but ok .. > > Patch 1 is an easy speedup of cancel_dirty_page(). Patches 2-6 refactor page > cache truncation code so that it is easier to batch radix tree operations. > Patch 7 implements batching of deletes from the radix tree which more than > makes up for the original regression. > > What do people think about this series? Batching locks is always a good idea. You'll likely see far more benefits under lock contention on larger systems. >From a quick read it looks good to me. Reviewed-by: Andi Kleen <ak@xxxxxxxxxxxxxxx> -Andi
