On Mon, May 18, 2020 at 12:12:36PM +0530, Anshuman Khandual wrote: > This adds the following two new VM events which will help in validating PMD > based THP migration without split. Statistics reported through these events > will help in performance debugging. > > 1. THP_PMD_MIGRATION_SUCCESS > 2. THP_PMD_MIGRATION_FAILURE > > Cc: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx> > Cc: Zi Yan <ziy@xxxxxxxxxx> > Cc: John Hubbard <jhubbard@xxxxxxxxxx> > Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> > Cc: linux-mm@xxxxxxxxx > Cc: linux-kernel@xxxxxxxxxxxxxxx > Signed-off-by: Anshuman Khandual <anshuman.khandual@xxxxxxx> Hi Anshuman, I'm neutral for additinal lines in /proc/vmstat. It's a classic (so widely used) but inflexible interface. Users disabling thp are not happy with many thp-related lines, but judging from the fact that we already have many thp-related lines some users really need them. So I feel hard to decide to agree or disagree with additional lines. I think that tracepoints are the more flexible interfaces for monitoring, so I'm interested more in whether thp migration could be monitorable via tracepoint. Do you have any idea/plan on it? Thanks, Naoya Horiguchi
