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 X-Spam-Level: X-Spam-Status: No, score=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_RED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 12A74C11F66 for ; Thu, 1 Jul 2021 01:48:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EC79961468 for ; Thu, 1 Jul 2021 01:48:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238393AbhGABvP (ORCPT ); Wed, 30 Jun 2021 21:51:15 -0400 Received: from mail.kernel.org ([198.145.29.99]:40584 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238384AbhGABvP (ORCPT ); Wed, 30 Jun 2021 21:51:15 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 3F58A6120C; Thu, 1 Jul 2021 01:48:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1625104125; bh=YOOzhUTqf7KWYxyFvUMrP7gImFxTqWLWGXQUYUpxmeA=; h=Date:From:To:Subject:In-Reply-To:From; b=EJHnh/B3d/0pOYMZqS6aopctm3R0gDAN9d5JEQoG3t9Z5lb5svMvm/qPEaqLoPqf9 HhYpYuXNcBvhLgwWl1HDPUBg/MWQM6FRBq8ftpB2V+mMSriNq0bpm7LHG4gLG8X+qm Kz+fEWYL71ZAlLuiXM98ZfQTdNyvt6ZJiMZLZxpY= Date: Wed, 30 Jun 2021 18:48:44 -0700 From: Andrew Morton To: aarcange@redhat.com, akpm@linux-foundation.org, almasrymina@google.com, axelrasmussen@google.com, bgeffon@google.com, dgilbert@redhat.com, hughd@google.com, jglisse@redhat.com, joe@perches.com, kirill@shutemov.name, linux-mm@kvack.org, lokeshgidra@google.com, mike.kravetz@oracle.com, mm-commits@vger.kernel.org, oupton@google.com, peterx@redhat.com, rppt@linux.vnet.ibm.com, sfr@canb.auug.org.au, shli@fb.com, shuah@kernel.org, torvalds@linux-foundation.org, viro@zeniv.linux.org.uk, wangqing@vivo.com Subject: [patch 031/192] userfaultfd/selftests: remove the time() check on delayed uffd Message-ID: <20210701014844.ASqKQfeHh%akpm@linux-foundation.org> In-Reply-To: <20210630184624.9ca1937310b0dd5ce66b30e7@linux-foundation.org> User-Agent: s-nail v14.8.16 Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org From: Peter Xu Subject: userfaultfd/selftests: remove the time() check on delayed uffd There seems to have no guarantee that time() will return the same for the two calls even if there's no delay, e.g. when a fault is accidentally crossing the changing of a second. Meanwhile, this message is also not helping that much since delay could happen with a lot of reasons, e.g., schedule latency of resolving thread. It may not mean an issue with uffd. Neither do I saw this error triggered either in the past runs. Even if it triggers, it'll be drown in all the rest of test logs. Remove it. Link: https://lkml.kernel.org/r/20210412232753.1012412-3-peterx@redhat.com Signed-off-by: Peter Xu Reviewed-by: Axel Rasmussen Cc: Alexander Viro Cc: Andrea Arcangeli Cc: Brian Geffon Cc: "Dr . David Alan Gilbert" Cc: Hugh Dickins Cc: Jerome Glisse Cc: Joe Perches Cc: Kirill A. Shutemov Cc: Lokesh Gidra Cc: Mike Kravetz Cc: Mike Rapoport Cc: Mina Almasry Cc: Oliver Upton Cc: Shaohua Li Cc: Shuah Khan Cc: Stephen Rothwell Cc: Wang Qing Signed-off-by: Andrew Morton --- tools/testing/selftests/vm/userfaultfd.c | 8 -------- 1 file changed, 8 deletions(-) --- a/tools/testing/selftests/vm/userfaultfd.c~userfaultfd-selftests-remove-the-time-check-on-delayed-uffd +++ a/tools/testing/selftests/vm/userfaultfd.c @@ -395,7 +395,6 @@ static void *locking_thread(void *arg) unsigned long long count; char randstate[64]; unsigned int seed; - time_t start; if (bounces & BOUNCE_RANDOM) { seed = (unsigned int) time(NULL) - bounces; @@ -432,7 +431,6 @@ static void *locking_thread(void *arg) page_nr += 1; page_nr %= nr_pages; - start = time(NULL); if (bounces & BOUNCE_VERIFY) { count = *area_count(area_dst, page_nr); if (!count) { @@ -495,12 +493,6 @@ static void *locking_thread(void *arg) count++; *area_count(area_dst, page_nr) = count_verify[page_nr] = count; pthread_mutex_unlock(area_mutex(area_dst, page_nr)); - - if (time(NULL) - start > 1) - fprintf(stderr, - "userfault too slow %ld " - "possible false positive with overcommit\n", - time(NULL) - start); } return NULL; _