On 11/08/2016 05:01 AM, Naoya Horiguchi wrote: > Hi everyone, > > I've updated thp migration patches for v4.9-rc2-mmotm-2016-10-27-18-27 > with feedbacks for ver.1. > > General description (no change since ver.1) > =========================================== > > This patchset enhances page migration functionality to handle thp migration > for various page migration's callers: > - mbind(2) > - move_pages(2) > - migrate_pages(2) > - cgroup/cpuset migration > - memory hotremove > - soft offline > > The main benefit is that we can avoid unnecessary thp splits, which helps us > avoid performance decrease when your applications handles NUMA optimization on > their own. > > The implementation is similar to that of normal page migration, the key point > is that we modify a pmd to a pmd migration entry in swap-entry like format.
Will it be better to have new THP_MIGRATE_SUCCESS and THP_MIGRATE_FAIL VM events to capture how many times the migration worked without first splitting the huge page and how many time it did not work ? Also do you have a test case which demonstrates this THP migration and kind of shows its better than the present split and move method ?
