Christoph Hellwig
2019-Feb-20 15:19 UTC
[RESEND PATCH 0/7] Add FOLL_LONGTERM to GUP fast and use it
On Tue, Feb 19, 2019 at 09:30:33PM -0800, ira.weiny at intel.com wrote:> From: Ira Weiny <ira.weiny at intel.com> > > Resending these as I had only 1 minor comment which I believe we have covered > in this series. I was anticipating these going through the mm tree as they > depend on a cleanup patch there and the IB changes are very minor. But they > could just as well go through the IB tree. > > NOTE: This series depends on my clean up patch to remove the write parameter > from gup_fast_permitted()[1] > > HFI1, qib, and mthca, use get_user_pages_fast() due to it performance > advantages. These pages can be held for a significant time. But > get_user_pages_fast() does not protect against mapping of FS DAX pages.This I don't get - if you do lock down long term mappings performance of the actual get_user_pages call shouldn't matter to start with. What do I miss?