On Thu, Jun 06, 2024 at 03:35:31PM +0100, Matthew Wilcox wrote: > On Thu, Jun 06, 2024 at 01:58:35PM +0000, Pankaj Raghav (Samsung) wrote: > > +++ b/tools/testing/selftests/mm/split_huge_page_test.c > > @@ -300,7 +300,7 @@ 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; > > + volatile int __attribute__((unused)) dummy = 0; > > The mistake made by whoever wrote this test was making 'dummy' a stack > variable. That lets the compiler figure out that it's unused. If you > make it a top-level variable (not static) so the compiler can't tell > whether it's referenced by a different compilation unit, it can't make > that deduction. And you don't need the stupid attibute or volatile on it. I did cringe a little before adding the volatile keyword. While not a fan of global variables, that might be better than all these keywords. I will send a v2 right away! Thanks. -- Pankaj