When insert and delete a vma, it will compute and propagate related subtree gap. After some investigation, we can reduce subtree gap propagation a little. [1]: This one reduce the propagation by update *next* gap after itself, since *next* must be a parent in this case. [2]: This one achieve this by unlinking vma from list. After applying these two patches, test shows it reduce 0.3% function call for vma_compute_subtree_gap. BTW, this series is based on some un-merged cleanup patched. --- This version is rebased on current linus tree, whose last commit is commit 9e8312f5e160 ("Merge tag 'nfs-for-5.3-3' of git://git.linux-nfs.org/projects/trondmy/linux-nfs"). Wei Yang (2): mm/mmap.c: update *next* gap after itself mm/mmap.c: unlink vma before rb_erase mm/mmap.c | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-) -- 2.17.1