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authorJohn Hubbard <jhubbard@nvidia.com>2020-12-14 19:05:21 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2020-12-15 12:13:38 -0800
commitf4f9bda418ab8b4dbc5372e9e2a28162f7777154 (patch)
tree1e4cb5f83f338a2bd249a92b55280d2c3e536add /mm/Kconfig
parenta9bed1e1c2a9bb36cdd29af0ef48044d1b9e8c2a (diff)
selftests/vm: gup_test: introduce the dump_pages() sub-test
For quite a while, I was doing a quick hack to gup_test.c (previously, gup_benchmark.c) whenever I wanted to try out my changes to dump_page(). This makes that hack unnecessary, and instead allows anyone to easily get the same coverage from a user space program. That saves a lot of time because you don't have to change the kernel, in order to test different pages and options. The new sub-test takes advantage of the existing gup_test infrastructure, which already provides a simple user space program, some allocated user space pages, an ioctl call, pinning of those pages (via either get_user_pages or pin_user_pages) and a corresponding kernel-side test invocation. There's not much more required, mainly just a couple of inputs from the user. In fact, the new test re-uses the existing command line options in order to get various helpful combinations (THP or normal, _fast or slow gup, gup vs. pup, and more). New command line options are: which pages to dump, and what type of "get/pin" to use. In order to figure out which pages to dump, the logic is: * If the user doesn't specify anything, the page 0 (the first page in the address range that the program sets up for testing) is dumped. * Or, the user can type up to 8 page indices anywhere on the command line. If you type more than 8, then it uses the first 8 and ignores the remaining items. For example: ./gup_test -ct -F 1 0 19 0x1000 Meaning: -c: dump pages sub-test -t: use THP pages -F 1: use pin_user_pages() instead of get_user_pages() 0 19 0x1000: dump pages 0, 19, and 4096 Link: https://lkml.kernel.org/r/20201026064021.3545418-7-jhubbard@nvidia.com Signed-off-by: John Hubbard <jhubbard@nvidia.com> Cc: Jérôme Glisse <jglisse@redhat.com> Cc: Jonathan Corbet <corbet@lwn.net> 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>
Diffstat (limited to 'mm/Kconfig')
-rw-r--r--mm/Kconfig6
1 files changed, 6 insertions, 0 deletions
diff --git a/mm/Kconfig b/mm/Kconfig
index e25e5cb2989f..350f2e23a94a 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -832,6 +832,12 @@ config GUP_TEST
get_user_pages*() and pin_user_pages*(), as well as smoke tests of
the non-_fast variants.
+ There is also a sub-test that allows running dump_page() on any
+ of up to eight pages (selected by command line args) within the
+ range of user-space addresses. These pages are either pinned via
+ pin_user_pages*(), or pinned via get_user_pages*(), as specified
+ by other command line arguments.
+
See tools/testing/selftests/vm/gup_test.c
config GUP_GET_PTE_LOW_HIGH