mm/gup_benchmark: rename to mm/gup_test

Patch series "selftests/vm: gup_test, hmm-tests, assorted improvements", v3.

Summary: This series provides two main things, and a number of smaller
supporting goodies.  The two main points are:

1) Add a new sub-test to gup_test, which in turn is a renamed version
   of gup_benchmark.  This sub-test allows nicer testing of dump_pages(),
   at least on user-space pages.

   For quite a while, I was doing a quick hack to gup_test.c whenever I
   wanted to try out changes to dump_page().  Then Matthew Wilcox asked me
   what I meant when I said "I used my dump_page() unit test", and I
   realized that it might be nice to check in a polished up version of
   that.

   Details about how it works and how to use it are in the commit
   description for patch #6 ("selftests/vm: gup_test: introduce the
   dump_pages() sub-test").

2) Fixes a limitation of hmm-tests: these tests are incredibly useful,
   but only if people actually build and run them.  And it turns out that
   libhugetlbfs is a little too effective at throwing a wrench in the
   works, there.  So I've added a little configuration check that removes
   just two of the 21 hmm-tests, if libhugetlbfs is not available.

   Further details in the commit description of patch #8
   ("selftests/vm: hmm-tests: remove the libhugetlbfs dependency").

Other smaller things that this series does:

a) Remove code duplication by creating gup_test.h.

b) Clear up the sub-test organization, and their invocation within
   run_vmtests.sh.

c) Other minor assorted improvements.

[1] v2 is here:
https://lore.kernel.org/linux-doc/20200929212747.251804-1-jhubbard@nvidia.com/

[2] https://lore.kernel.org/r/CAHk-=wgh-TMPHLY3jueHX7Y2fWh3D+nMBqVS__AZm6-oorquWA@mail.gmail.com

This patch (of 9):

Rename nearly every "gup_benchmark" reference and file name to "gup_test".
The one exception is for the actual gup benchmark test itself.

The current code already does a *little* bit more than benchmarking, and
definitely covers more than get_user_pages_fast().  More importantly,
however, subsequent patches are about to add some functionality that is
non-benchmark related.

Closely related changes:

* Kconfig: in addition to renaming the options from GUP_BENCHMARK to
  GUP_TEST, update the help text to reflect that it's no longer a
  benchmark-only test.

Link: https://lkml.kernel.org/r/20201026064021.3545418-1-jhubbard@nvidia.com
Link: https://lkml.kernel.org/r/20201026064021.3545418-2-jhubbard@nvidia.com
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 10 insertions, 5 deletions

diff --git a/mm/Kconfig b/mm/Kconfig
index 390165ffbb0f..e25e5cb2989f 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -821,13 +821,18 @@ config PERCPU_STATS
 	  information includes global and per chunk statistics, which can
 	  be used to help understand percpu memory usage.
 
-config GUP_BENCHMARK
-	bool "Enable infrastructure for get_user_pages() and related calls benchmarking"
+config GUP_TEST
+	bool "Enable infrastructure for get_user_pages()-related unit tests"
 	help
-	  Provides /sys/kernel/debug/gup_benchmark that helps with testing
-	  performance of get_user_pages() and related calls.
+	  Provides /sys/kernel/debug/gup_test, which in turn provides a way
+	  to make ioctl calls that can launch kernel-based unit tests for
+	  the get_user_pages*() and pin_user_pages*() family of API calls.
 
-	  See tools/testing/selftests/vm/gup_benchmark.c
+	  These tests include benchmark testing of the _fast variants of
+	  get_user_pages*() and pin_user_pages*(), as well as smoke tests of
+	  the non-_fast variants.
+
+	  See tools/testing/selftests/vm/gup_test.c
 
 config GUP_GET_PTE_LOW_HIGH
 	bool