These changes are based on Jason's rdma/hmm branch (5.4.0-rc1).
Patch 1 was previously posted here [1] but was dropped from that orginal
series. Hopefully, the tests will reduce concerns about edge conditions.
I'm sure more tests could be usefully added but I thought this was a good
starting point.
Changes since v2:
patch 1:
Removed hmm_range_needs_fault() and just use hmm_range_need_fault().
Updated the change log to include that it fixes a bug where
hmm_range_fault() incorrectly returned an error when no fault is requested.
patch 2:
Removed the confusing change log wording about DMA.
Changed hmm_range_fault() to return the PFN of the zero page like any other
page.
patch 3:
Adjusted the test code to match the new zero page behavior.
Changes since v1:
Rebased to Jason's rdma/hmm branch (5.4.0-rc1).
Cleaned up locking for the test driver's page tables.
Incorporated Christoph Hellwig's comments.
[1] https://lore.kernel.org/linux-mm/[email protected]/
Ralph Campbell (3):
mm/hmm: make full use of walk_page_range()
mm/hmm: allow snapshot of the special zero page
mm/hmm/test: add self tests for HMM
MAINTAINERS | 3 +
drivers/char/Kconfig | 11 +
drivers/char/Makefile | 1 +
drivers/char/hmm_dmirror.c | 1566 ++++++++++++++++++++++++
include/Kbuild | 1 +
include/uapi/linux/hmm_dmirror.h | 74 ++
mm/hmm.c | 136 +-
tools/testing/selftests/vm/.gitignore | 1 +
tools/testing/selftests/vm/Makefile | 3 +
tools/testing/selftests/vm/config | 3 +
tools/testing/selftests/vm/hmm-tests.c | 1311 ++++++++++++++++++++
tools/testing/selftests/vm/run_vmtests | 16 +
tools/testing/selftests/vm/test_hmm.sh | 97 ++
13 files changed, 3158 insertions(+), 65 deletions(-)
create mode 100644 drivers/char/hmm_dmirror.c
create mode 100644 include/uapi/linux/hmm_dmirror.h
create mode 100644 tools/testing/selftests/vm/hmm-tests.c
create mode 100755 tools/testing/selftests/vm/test_hmm.sh
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2.20.1