From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3CEA3C7EE24 for ; Mon, 5 Jun 2023 22:44:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231933AbjFEWof (ORCPT ); Mon, 5 Jun 2023 18:44:35 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40264 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231929AbjFEWoe (ORCPT ); Mon, 5 Jun 2023 18:44:34 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1F200100 for ; Mon, 5 Jun 2023 15:44:33 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id AC56662B72 for ; Mon, 5 Jun 2023 22:44:32 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0E42BC433D2; Mon, 5 Jun 2023 22:44:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1686005072; bh=bsG3GKRrH4k424n/jawMAnilo2OaEYvzP+qBodABL3c=; h=Date:To:From:Subject:From; b=ASOxOwnc32lPqz8otahwgZ/bScYJjT402RDBq49bplAQ+/acIXyjozotci0h1/qCF /bIIxRfcfEcQFly3JLK3KdMcv0qozNuBTDrZcY3cqFKdrKES68BLkLY18LCb5z+JKJ PR0IOT75npUivf44JIzBfXhbu5tUASHPWWTNK2Og= Date: Mon, 05 Jun 2023 15:44:31 -0700 To: mm-commits@vger.kernel.org, usama.anjum@collabora.com, shuah@kernel.org, peterx@redhat.com, nathan@kernel.org, david@redhat.com, corbet@lwn.net, jhubbard@nvidia.com, akpm@linux-foundation.org From: Andrew Morton Subject: + selftests-mm-fix-unused-variable-warnings-in-hugetlb-madvisec-migrationc.patch added to mm-unstable branch Message-Id: <20230605224432.0E42BC433D2@smtp.kernel.org> Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org The patch titled Subject: selftests/mm: fix unused variable warnings in hugetlb-madvise.c, migration.c has been added to the -mm mm-unstable branch. Its filename is selftests-mm-fix-unused-variable-warnings-in-hugetlb-madvisec-migrationc.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/selftests-mm-fix-unused-variable-warnings-in-hugetlb-madvisec-migrationc.patch This patch will later appear in the mm-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: John Hubbard Subject: selftests/mm: fix unused variable warnings in hugetlb-madvise.c, migration.c Date: Fri, 2 Jun 2023 19:15:49 -0700 Dummy variables are required in order to make these two (similar) routines work, so in both cases, declare the variables as volatile in order to avoid the clang compiler warning. Furthermore, in order to ensure that each test actually does what is intended, add an asm volatile invocation (thanks to David Hildenbrand for the suggestion), with a clarifying comment so that it survives future maintenance. Link: https://lkml.kernel.org/r/20230603021558.95299-3-jhubbard@nvidia.com Signed-off-by: John Hubbard Reviewed-by: David Hildenbrand Reviewed-by: Peter Xu Cc: Jonathan Corbet Cc: Muhammad Usama Anjum Cc: Nathan Chancellor Cc: Shuah Khan Signed-off-by: Andrew Morton --- tools/testing/selftests/mm/hugetlb-madvise.c | 8 ++++++-- tools/testing/selftests/mm/migration.c | 5 ++++- 2 files changed, 10 insertions(+), 3 deletions(-) --- a/tools/testing/selftests/mm/hugetlb-madvise.c~selftests-mm-fix-unused-variable-warnings-in-hugetlb-madvisec-migrationc +++ a/tools/testing/selftests/mm/hugetlb-madvise.c @@ -65,11 +65,15 @@ void write_fault_pages(void *addr, unsig void read_fault_pages(void *addr, unsigned long nr_pages) { - unsigned long dummy = 0; + volatile unsigned long dummy = 0; unsigned long i; - for (i = 0; i < nr_pages; i++) + for (i = 0; i < nr_pages; i++) { dummy += *((unsigned long *)(addr + (i * huge_page_size))); + + /* Prevent the compiler from optimizing out the entire loop: */ + asm volatile("" : "+r" (dummy)); + } } int main(int argc, char **argv) --- a/tools/testing/selftests/mm/migration.c~selftests-mm-fix-unused-variable-warnings-in-hugetlb-madvisec-migrationc +++ a/tools/testing/selftests/mm/migration.c @@ -95,12 +95,15 @@ int migrate(uint64_t *ptr, int n1, int n void *access_mem(void *ptr) { - uint64_t y = 0; + volatile uint64_t y = 0; volatile uint64_t *x = ptr; while (1) { pthread_testcancel(); y += *x; + + /* Prevent the compiler from optimizing out the writes to y: */ + asm volatile("" : "+r" (y)); } return NULL; _ Patches currently in -mm which might be from jhubbard@nvidia.com are selftests-mm-fix-uffd-stress-unused-function-warning.patch selftests-mm-fix-unused-variable-warnings-in-hugetlb-madvisec-migrationc.patch selftests-mm-fix-warning-expression-which-evaluates-to-zero-in-mlock2-testsc.patch selftests-mm-fix-invocation-of-tests-that-are-run-via-shell-scripts.patch selftests-mm-gitignore-add-mkdirty-va_high_addr_switch.patch selftests-mm-fix-two-wformat-security-warnings-in-uffd-builds.patch selftests-mm-fix-a-possibly-uninitialized-warning-in-pkey-x86h.patch selftests-mm-fix-uffd-unit-testsc-build-failure-due-to-missing-madv_collapse.patch selftests-mm-move-psize-pshift-into-vm_utilsc.patch selftests-mm-move-uffd-routines-from-vm_utilc-to-uffd-commonc.patch documentation-kselftest-make-headers-is-a-prerequisite.patch selftests-error-out-if-kernel-header-files-are-not-yet-built.patch