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 7B6BCC7EE29 for ; Wed, 7 Jun 2023 02:37:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234963AbjFGChX (ORCPT ); Tue, 6 Jun 2023 22:37:23 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50188 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234778AbjFGChV (ORCPT ); Tue, 6 Jun 2023 22:37:21 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 928F8E78 for ; Tue, 6 Jun 2023 19:37:20 -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 2F7B1639DA for ; Wed, 7 Jun 2023 02:37:20 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6A37EC433D2; Wed, 7 Jun 2023 02:37:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1686105439; bh=WOIyZDkOByKdexFA7WJRjlGiw5qRXMSuU1MQL4BuhDs=; h=Date:To:From:Subject:From; b=C4nCTa4782DnBqjTnMa2EU2sKCFzgARV5xRTyv7lkoVpUTt9XlR+e1pj7FUpzSakl v5Qz4cUChtRY3JHKxBqFTp1cQq2G3jXJ03IKWk+XuyX0gXKY/Xi9R8lSskMhUP9Xa0 el/Pnsw7qpTgFJ+wGZPB331FsNI3L1JfRgvW7c4E= Date: Tue, 06 Jun 2023 19:37:18 -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: <20230607023719.6A37EC433D2@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: Tue, 6 Jun 2023 00:16:28 -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/20230606071637.267103-3-jhubbard@nvidia.com Signed-off-by: John Hubbard Reviewed-by: David Hildenbrand Reviewed-by: Peter Xu Tested-by: Muhammad Usama Anjum Cc: Jonathan Corbet 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-build-failures-due-to-missing-madv_collapse.patch selftests-mm-move-certain-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 selftests-error-out-if-kernel-header-files-are-not-yet-built-fix.patch