[PATCH 0/2] put_user_page*(): start converting the call sites

[john.hubbard@gmail.com]

From: John Hubbard <jhubbard@nvidia.com>

Hi,

Summary: I'd like these two patches to go into the next convenient cycle.
I *think* that means 4.21.

Details

At the Linux Plumbers Conference, we talked about this approach [1], and
the primary lingering concern was over performance. Tom Talpey helped me
through a much more accurate run of the fio performance test, and now
it's looking like an under 1% performance cost, to add and remove pages
from the LRU (this is only paid when dealing with get_user_pages) [2]. So
we should be fine to start converting call sites.

This patchset gets the conversion started. Both patches already had a fair
amount of review.

(Tom, I'll add you Tested-by to the actual implementation that moves
pages on and off the LRU. These first two patches don't do that.)

[1] https://linuxplumbersconf.org/event/2/contributions/126/
    "RDMA and get_user_pages"

[2] https://lore.kernel.org/r/79d1ee27-9ea0-3d15-3fc4-97c1bd79c990@talpey.com

John Hubbard (2):
  mm: introduce put_user_page*(), placeholder versions
  infiniband/mm: convert put_page() to put_user_page*()

 drivers/infiniband/core/umem.c              |  7 +-
 drivers/infiniband/core/umem_odp.c          |  2 +-
 drivers/infiniband/hw/hfi1/user_pages.c     | 11 ++-
 drivers/infiniband/hw/mthca/mthca_memfree.c |  6 +-
 drivers/infiniband/hw/qib/qib_user_pages.c  | 11 ++-
 drivers/infiniband/hw/qib/qib_user_sdma.c   |  6 +-
 drivers/infiniband/hw/usnic/usnic_uiom.c    |  7 +-
 include/linux/mm.h                          | 20 ++++++
 mm/swap.c                                   | 80 +++++++++++++++++++++
 9 files changed, 123 insertions(+), 27 deletions(-)

-- 
2.19.2