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charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspam-User: X-Rspamd-Queue-Id: E281240014 X-Rspamd-Server: rspam07 X-Stat-Signature: wy97ccko4z6pm1jwyn9ysxap8m68365s X-HE-Tag: 1769103570-202153 X-HE-Meta: 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 22/01/2026 5:02 pm, Kevin Brodsky wrote: > FORCE_READ(*addr) ensures that the compiler will emit a load from > addr. Several tests need to trigger such a load for a range of > pages, ensuring that every page is faulted in, if it wasn't already. > > Introduce a new helper force_read_pages() that does exactly that and > replace existing loops with a call to it. > > The step size (regular/huge page size) is preserved for all loops, > except in split_huge_page_test. Reading every byte is unnecessary; > we now read every huge page, matching the following call to > check_huge_file(). > > Reviewed-by: Dev Jain > Signed-off-by: Kevin Brodsky > --- > tools/testing/selftests/mm/hugetlb-madvise.c | 9 +-------- > tools/testing/selftests/mm/pfnmap.c | 9 +++------ > tools/testing/selftests/mm/split_huge_page_test.c | 6 +----- > tools/testing/selftests/mm/vm_util.h | 7 +++++++ > 4 files changed, 12 insertions(+), 19 deletions(-) > > diff --git a/tools/testing/selftests/mm/hugetlb-madvise.c b/tools/testing/selftests/mm/hugetlb-madvise.c > index 05d9d2805ae4..5b12041fa310 100644 > --- a/tools/testing/selftests/mm/hugetlb-madvise.c > +++ b/tools/testing/selftests/mm/hugetlb-madvise.c > @@ -47,14 +47,7 @@ void write_fault_pages(void *addr, unsigned long nr_pages) > > void read_fault_pages(void *addr, unsigned long nr_pages) > { > - unsigned long i; > - > - for (i = 0; i < nr_pages; i++) { > - unsigned long *addr2 = > - ((unsigned long *)(addr + (i * huge_page_size))); > - /* Prevent the compiler from optimizing out the entire loop: */ > - FORCE_READ(*addr2); > - } > + force_read_pages(addr, nr_pages, huge_page_size); > } > > int main(int argc, char **argv) > diff --git a/tools/testing/selftests/mm/pfnmap.c b/tools/testing/selftests/mm/pfnmap.c > index f546dfb10cae..45b5f1cf6019 100644 > --- a/tools/testing/selftests/mm/pfnmap.c > +++ b/tools/testing/selftests/mm/pfnmap.c > @@ -35,18 +35,15 @@ static void signal_handler(int sig) > > static int test_read_access(char *addr, size_t size, size_t pagesize) > { > - size_t offs; > int ret; > > if (signal(SIGSEGV, signal_handler) == SIG_ERR) > return -EINVAL; > > ret = sigsetjmp(sigjmp_buf_env, 1); > - if (!ret) { > - for (offs = 0; offs < size; offs += pagesize) > - /* Force a read that the compiler cannot optimize out. */ > - *((volatile char *)(addr + offs)); > - } > + if (!ret) > + force_read_pages(addr, size/pagesize, pagesize); > + > if (signal(SIGSEGV, SIG_DFL) == SIG_ERR) > return -EINVAL; > > diff --git a/tools/testing/selftests/mm/split_huge_page_test.c b/tools/testing/selftests/mm/split_huge_page_test.c > index 40799f3f0213..e0167111bdd1 100644 > --- a/tools/testing/selftests/mm/split_huge_page_test.c > +++ b/tools/testing/selftests/mm/split_huge_page_test.c > @@ -652,11 +652,7 @@ static int create_pagecache_thp_and_fd(const char *testfile, size_t fd_size, > } > madvise(*addr, fd_size, MADV_HUGEPAGE); > > - for (size_t i = 0; i < fd_size; i++) { > - char *addr2 = *addr + i; > - > - FORCE_READ(*addr2); > - } > + force_read_pages(*addr, fd_size / pmd_pagesize, pmd_pagesize); > > if (!check_huge_file(*addr, fd_size / pmd_pagesize, pmd_pagesize)) { > ksft_print_msg("No large pagecache folio generated, please provide a filesystem supporting large folio\n"); > diff --git a/tools/testing/selftests/mm/vm_util.h b/tools/testing/selftests/mm/vm_util.h > index 6ad32b1830f1..522f7f9050f5 100644 > --- a/tools/testing/selftests/mm/vm_util.h > +++ b/tools/testing/selftests/mm/vm_util.h > @@ -54,6 +54,13 @@ static inline unsigned int pshift(void) > return __page_shift; > } > > +static inline void force_read_pages(char *addr, unsigned int nr_pages, > + size_t pagesize) > +{ > + for (unsigned int i = 0; i < nr_pages; i++) > + FORCE_READ(addr[i * pagesize]); > +} Reviewed-by: Muhammad Usama Anjum > + > bool detect_huge_zeropage(void); > > /*