| Message ID | 20240606154428.672643-1-kernel@pankajraghav.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | [v2] selftests/mm: use global variable to not optimize mmap read variable | expand |
On 6 Jun 2024, at 8:44, Pankaj Raghav (Samsung) wrote: > From: Pankaj Raghav <p.raghav@samsung.com> > > create_pagecache_thp_and_fd() in split_huge_page_test.c used the > variable dummy to perform mmap read. > > However, this test was skipped even on XFS which has large folio > support. The issue was compiler (gcc 13.2.0) was optimizing out the > dummy variable, therefore, not creating huge page in the page cache. > > Make it as a global variable to force the compiler not to optimize out > the loop where we read from the mmaped addr. > > Signed-off-by: Pankaj Raghav <p.raghav@samsung.com> > --- > Changes since v1: > - Make the dummy variable as a global variable(willy). > > tools/testing/selftests/mm/split_huge_page_test.c | 6 +++++- > 1 file changed, 5 insertions(+), 1 deletion(-) > Reviewed-by: Zi Yan <ziy@nvidia.com> Thanks. Best Regards, Yan, Zi
diff --git a/tools/testing/selftests/mm/split_huge_page_test.c b/tools/testing/selftests/mm/split_huge_page_test.c index d3c7f5fb3e7b..c4857de2c042 100644 --- a/tools/testing/selftests/mm/split_huge_page_test.c +++ b/tools/testing/selftests/mm/split_huge_page_test.c @@ -23,6 +23,11 @@ uint64_t pagesize; unsigned int pageshift; uint64_t pmd_pagesize; +/* + * Used by create_pagecache_thp_and_fd() to do mmap read. + * Made it as global to avoid compiler optimizing out the variable. + */ +int dummy; #define SPLIT_DEBUGFS "/sys/kernel/debug/split_huge_pages" #define SMAP_PATH "/proc/self/smaps" @@ -300,7 +305,6 @@ int create_pagecache_thp_and_fd(const char *testfile, size_t fd_size, int *fd, char **addr) { size_t i; - int __attribute__((unused)) dummy = 0; srand(time(NULL));