From f4f9bda418ab8b4dbc5372e9e2a28162f7777154 Mon Sep 17 00:00:00 2001 From: John Hubbard Date: Mon, 14 Dec 2020 19:05:21 -0800 Subject: selftests/vm: gup_test: introduce the dump_pages() sub-test MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Cc: Jérôme Glisse Cc: Jonathan Corbet Cc: Ralph Campbell Cc: Shuah Khan Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/gup_test.c | 56 ++++++++++++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 54 insertions(+), 2 deletions(-) (limited to 'mm/gup_test.c') diff --git a/mm/gup_test.c b/mm/gup_test.c index 173bb38f3688..087ddaf30eb4 100644 --- a/mm/gup_test.c +++ b/mm/gup_test.c @@ -7,7 +7,7 @@ #include "gup_test.h" static void put_back_pages(unsigned int cmd, struct page **pages, - unsigned long nr_pages) + unsigned long nr_pages, unsigned int gup_test_flags) { unsigned long i; @@ -23,6 +23,15 @@ static void put_back_pages(unsigned int cmd, struct page **pages, case PIN_LONGTERM_BENCHMARK: unpin_user_pages(pages, nr_pages); break; + case DUMP_USER_PAGES_TEST: + if (gup_test_flags & GUP_TEST_FLAG_DUMP_PAGES_USE_PIN) { + unpin_user_pages(pages, nr_pages); + } else { + for (i = 0; i < nr_pages; i++) + put_page(pages[i]); + + } + break; } } @@ -49,6 +58,37 @@ static void verify_dma_pinned(unsigned int cmd, struct page **pages, } } +static void dump_pages_test(struct gup_test *gup, struct page **pages, + unsigned long nr_pages) +{ + unsigned int index_to_dump; + unsigned int i; + + /* + * Zero out any user-supplied page index that is out of range. Remember: + * .which_pages[] contains a 1-based set of page indices. + */ + for (i = 0; i < GUP_TEST_MAX_PAGES_TO_DUMP; i++) { + if (gup->which_pages[i] > nr_pages) { + pr_warn("ZEROING due to out of range: .which_pages[%u]: %u\n", + i, gup->which_pages[i]); + gup->which_pages[i] = 0; + } + } + + for (i = 0; i < GUP_TEST_MAX_PAGES_TO_DUMP; i++) { + index_to_dump = gup->which_pages[i]; + + if (index_to_dump) { + index_to_dump--; // Decode from 1-based, to 0-based + pr_info("---- page #%u, starting from user virt addr: 0x%llx\n", + index_to_dump, gup->addr); + dump_page(pages[index_to_dump], + "gup_test: dump_pages() test"); + } + } +} + static int __gup_test_ioctl(unsigned int cmd, struct gup_test *gup) { @@ -111,6 +151,14 @@ static int __gup_test_ioctl(unsigned int cmd, gup->flags | FOLL_LONGTERM, pages + i, NULL); break; + case DUMP_USER_PAGES_TEST: + if (gup->flags & GUP_TEST_FLAG_DUMP_PAGES_USE_PIN) + nr = pin_user_pages(addr, nr, gup->flags, + pages + i, NULL); + else + nr = get_user_pages(addr, nr, gup->flags, + pages + i, NULL); + break; default: ret = -EINVAL; goto unlock; @@ -134,9 +182,12 @@ static int __gup_test_ioctl(unsigned int cmd, */ verify_dma_pinned(cmd, pages, nr_pages); + if (cmd == DUMP_USER_PAGES_TEST) + dump_pages_test(gup, pages, nr_pages); + start_time = ktime_get(); - put_back_pages(cmd, pages, nr_pages); + put_back_pages(cmd, pages, nr_pages, gup->flags); end_time = ktime_get(); gup->put_delta_usec = ktime_us_delta(end_time, start_time); @@ -161,6 +212,7 @@ static long gup_test_ioctl(struct file *filep, unsigned int cmd, case PIN_LONGTERM_BENCHMARK: case GUP_BASIC_TEST: case PIN_BASIC_TEST: + case DUMP_USER_PAGES_TEST: break; default: return -EINVAL; -- cgit 1.4.1