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2020-12-15selftests/vm: gup_test: introduce the dump_pages() sub-testJohn Hubbard
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>
2020-12-15selftests/vm: only some gup_test items are really benchmarksJohn Hubbard
Therefore, some minor cleanup and improvements are in order: 1. Rename the other items appropriately. 2. Stop reporting timing information on the non-benchmark items. It's still being recorded and is available, but there's no point in cluttering up the report with data that no one reasonably needs to check. 3. Don't do iterations, for non-benchmark items. 4. Print out a shorter, more appropriate report for the non-benchmark tests. 5. Add the command that was run, to the report. This really helps, as there are quite a lot of options now. 6. Use a larger integer type for cmd, now that it's being compared Otherwise it doesn't work, because in this case cmd is about 3 billion, which is the perfect size for problems with signed vs unsigned int. Link: https://lkml.kernel.org/r/20201026064021.3545418-6-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>
2020-12-15selftests/vm: use a common gup_test.hJohn Hubbard
Avoid the need to copy-paste the gup_test ioctl commands and the struct gup_test definition, between the kernel and the user space application, by providing a new header file for these. This allows easier and safer adding of new ioctl calls, as well as reducing the overall line count. Details: The header file has to be able to compile independently, because of the arguably unfortunate way that the Makefile is written: the Makefile tries to build all of its prerequisites, when really it should be only building the .c files, and leaving the other prerequisites (LOCAL_HDRS) as pure dependencies. That Makefile limitation is probably not worth fixing, but it explains why one of the includes had to be moved into the new header file. Also: simplify the ioctl struct (struct gup_test), by deleting the unused __expansion[10] field. This sort of thing is what you might see in a stable ABI, but this low-level, kernel-developer-oriented selftests/vm system is very much not subject to ABI stability. So "expansion" and "reserved" fields are unnecessary here. Link: https://lkml.kernel.org/r/20201026064021.3545418-3-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>