Hello, conversion of page cache to xarray (commit 69b6c1319b6 "mm: Convert truncate to XArray" in particular) has regressed performance of page cache truncation by about 10% (see my original report here [1]). This patch series aims at improving the truncation to get some of that regression back. The first patch fixes a long standing bug with xas_for_each_marked() that I've uncovered when debugging my patches. The remaining patches then work towards the ability to stop clearing marks in xas_store() which improves truncation performance by about 6%. The patches have passed radix_tree tests in tools/testing and also fstests runs for ext4 & xfs. Honza [1] https://lore.kernel.org/linux-mm/20190226165628.GB24711@xxxxxxxxxxxxxx
