From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752546AbeDTRUH (ORCPT ); Fri, 20 Apr 2018 13:20:07 -0400 Received: from mail-bn3nam01on0079.outbound.protection.outlook.com ([104.47.33.79]:47656 "EHLO NAM01-BN3-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751092AbeDTRUF (ORCPT ); Fri, 20 Apr 2018 13:20:05 -0400 Authentication-Results: intel.com; dkim=none (message not signed) header.d=none;intel.com; dmarc=none action=none header.from=caviumnetworks.com; From: Yury Norov To: Fengguang Wu , Dmitry Vyukov , Kefeng Wang , Andrew Morton , Clement Courbet , Arnd Bergmann , Geert Uytterhoeven , linux-kernel@vger.kernel.org, lkp@01.org Cc: Yury Norov Subject: [PATCH] lib: avoid soft lockup in test_find_first_bit() Date: Fri, 20 Apr 2018 20:19:49 +0300 Message-Id: <20180420171949.15710-1-ynorov@caviumnetworks.com> X-Mailer: git-send-email 2.14.1 MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [176.59.47.253] X-ClientProxiedBy: VI1P189CA0019.EURP189.PROD.OUTLOOK.COM (2603:10a6:802:2a::32) To BYAPR07MB4375.namprd07.prod.outlook.com (2603:10b6:a02:c0::18) X-MS-PublicTrafficType: Email X-Microsoft-Antispam: UriScan:;BCL:0;PCL:0;RULEID:(7020095)(4652020)(5600026)(4534165)(4627221)(201703031133081)(201702281549075)(2017052603328)(7153060)(7193020);SRVR:BYAPR07MB4375; X-Microsoft-Exchange-Diagnostics: 1;BYAPR07MB4375;3:N0+jwDhLrzhi2t20Wziqun1Zi2UxSZzF6QgA5oDPKIqcmFt54Warn3EssPwdAn7NVPXxF8PM+mfXmhoQZg3uGXxoD+mYzYEOzUM/Q7ZqMWtTe9jriqReTqlNFcqZ0LWmmw23XGOXdCrr070ZwcHcBC1CyTe8Q7p7YHbR2RJ5O9H5p4+La4kKBj/InmimeB5ZKDB4WO0MpA/KDEIpyz5IaFgEWiYfvRR8LIecoom/nLVD5phbb4IUexld4CVMMs0J;25:ErVN2ZtSls1VwHENf0X1xadLg5XyXScy5e9D5d7Si39JyuBdnELvDp9d1oUeZdif+ztoIQ6N0c3yS04ky9cwC8DLsPVH15ArdaEd7CsWHsAd50WzhSVdypPOAsnGhgN1Z4On1mJ28pWoIhObX2Yyz+OJOkeY5dsM1cII4106AAR5VJ6Nx8U95dkELs+qmC8P72VS67cTQUZRtxMKlF1h9XnJO/5q6juPyIckw+KmEc+fDrsisXVtLSjTNfPA0IJ6uJuCHmlz4V5dfVzHlVMCPgi7TTZAW5Qrr8XO2wqkOw+WJMlGziseaTOUbuLFu/FPlDZZFWKbgtayU5cO/NB4/w==;31:nGNWiXgQ5LmZ0Jydq/9xqjbg1t/Af5/jhc9dyXfo71pZgGHT9yQVBd50GQ6DP1t7OgzwSrIHGSOFzDPxyPNKcG7zMi/mSdazSoSk3RKMGdyVFHIDI4OaTF/V3VLuwEjR+tVSUd99OjVZxlAYrun+Icc0Tj1HzwRH2XFxenD3wylECJJoz6JxesWSPuaEiFV9Lyf1BK4VV/LqxKxLm2bWxtOzDV+xyZKafwf87bRKnm0= X-MS-TrafficTypeDiagnostic: BYAPR07MB4375: X-Microsoft-Exchange-Diagnostics: 1;BYAPR07MB4375;20: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;4:+djsp33b0z7tTjLMVfFthYmgrjq+YAHKmrbQBg/emY+ZJSy4LFt2T6yof4SkQzVP2yrF+6EvfwU+GiuS/xn4XFFFZ6eM1o5H+LTMsnP6utwXcnHLHCMVD5W96Pjo8LNlE35IaAyakTOAM7/r1PaBiSGB43AR4Li8n5g5bKuG72gNZXkrxae+ICA1PG8SjhoIxX9hm35YtM6UjEopB7bsNPpw9GTidfUBSGGhPD6w3CroSY9f62aKN9Tk2/uTfeqGFP3ZP3J/P8osbTXAGIX14N2Nuexcj9ip1Qfx1Nlh38iSgozXHOC95HbtX1U6Q3Uk X-Microsoft-Antispam-PRVS: X-Exchange-Antispam-Report-Test: UriScan:(228905959029699); X-Exchange-Antispam-Report-CFA-Test: BCL:0;PCL:0;RULEID:(8211001083)(6040522)(2401047)(8121501046)(5005006)(10201501046)(3002001)(3231232)(944501396)(52105095)(93006095)(6041310)(20161123564045)(201703131423095)(201702281528075)(20161123555045)(201703061421075)(201703061406153)(20161123558120)(20161123560045)(20161123562045)(6072148)(201708071742011);SRVR:BYAPR07MB4375;BCL:0;PCL:0;RULEID:;SRVR:BYAPR07MB4375; X-Forefront-PRVS: 0648FCFFA8 X-Forefront-Antispam-Report: SFV:NSPM;SFS:(10009020)(39380400002)(346002)(39850400004)(366004)(376002)(396003)(6486002)(53936002)(3846002)(107886003)(76506005)(8936002)(186003)(42882007)(16526019)(50226002)(5660300001)(72206003)(1857600001)(66066001)(81166006)(8676002)(6116002)(50466002)(478600001)(48376002)(26005)(1076002)(4326008)(7736002)(575784001)(305945005)(59450400001)(6666003)(6496006)(2906002)(386003)(25786009)(316002)(47776003)(110136005)(16586007)(956004)(2616005)(36756003)(52116002)(476003);DIR:OUT;SFP:1101;SCL:1;SRVR:BYAPR07MB4375;H:localhost;FPR:;SPF:None;LANG:en;MLV:sfv; X-Microsoft-Exchange-Diagnostics: =?us-ascii?Q?1;BYAPR07MB4375;23:bNoW6nNf2Lt5PzqJLchrcEkG12sjjv6OtmiOrRM0j?= =?us-ascii?Q?NBxPV2/7pN8dulw1dLCw21u+CvtPmwXLmzRXR5BHBkprWRfEQ0P4dHixLaDc?= =?us-ascii?Q?FM2hyR1yaOsErmS+oIXwzpN3kB5KZJQI1kpAEC2pJYyo4ImfKYowC3fFnxMG?= =?us-ascii?Q?fOi1JwYhNQKG2qeYsQ6sYIPQg278P3YrgA6YhuVwX8lT9nmbLfh9I6DjRyfF?= =?us-ascii?Q?gPRWbGyCpwYCz8IuIHvmDDIfBW2XmoBurxwEQhkXIE91vDpk0RlyBXgpy9xO?= =?us-ascii?Q?cqz7I357oHzCJREUUZA+83MPGDIsVIK+nuDBRlsQt84LQEQx4MWJcA9WZ65f?= =?us-ascii?Q?1L/IS1T2EuuwyufcqUBYN1BFrV5VudcN3Mxtg3DVxZAgZXll0qm1x7dIG9/E?= =?us-ascii?Q?NEqnis3aGWjGO/QVa+gM/l914t8Mn2QVeDQQe/t8Q5K9w1JrfEZbgU8Enzoz?= =?us-ascii?Q?fHRaCgGaYNBguGwHvquuudZtq+F40iiUhns7GOqOsQYLzgRTkJzIGRsgjw9M?= =?us-ascii?Q?JX/04Q2qAdUBjCKysEZ4PUANRGAfFC2qjnvqMQtKTCDOhWMOSaFmMKjNt73M?= =?us-ascii?Q?fAbJ8SpYqQXCzBgIoWbE5A9jpJno2zv1gI7SsYgEhhvXTArJYjxFp3EdHKB0?= =?us-ascii?Q?KRQN1jzbtMRu7Uk6C0u1DnFu2mN66QNRQAQUIVaGk2NulYlCypW6oqh0qd2X?= =?us-ascii?Q?4a1iFp518CyPzmFS6tnFr+RbPpHJgkYval3wp+G5QLxlsNw26D8TePGdmO8u?= =?us-ascii?Q?d1+oT6oSHdbMsiS8l/oygG5P+PFjSP1xWs+loXFoRelQSDGjkUXtgAixLqy5?= =?us-ascii?Q?5jwqe2S7FK9fjexxOdHlpW6wSLU5Mng28uAuwAlKV3QwgsxkH5gcvMQGX8Ni?= =?us-ascii?Q?rtBQOdRGq3e8as58AtnSeqcJ7uATnmE8+GAhay8xkeU0zrg9D006GW/ONWJs?= =?us-ascii?Q?Cn1tnqdCGkn4FR6hXONF6jaJ4AeKakpzkPfyGxXDdVqCf9UwOxH3kfmGevA5?= =?us-ascii?Q?gDTyVKZtjND/LcV+Mgj6bbFSp3bSYoagOD/OxseoFUfICNG9hDhyublviKZz?= =?us-ascii?Q?J+CyM/NpeH2itaAI5IalF+/hN1X?= X-Microsoft-Antispam-Message-Info: rBnUcLEKrraZcPlCgvkPPrNsnrzN5aPGkKWLbyPok8IokmtXCErmhscWU5kMhWWzuPBtQ837fJGmB3TeKegT7D2WgXRoJ4WvwqFb+roqtmhLUcKE5kuDXWa3mIMFaIA6+ATQdGISjOX2ZovurFaHehZ7hYRLLDNneYNaPyMZ306yBtPnAwM/OfcCTniuQcpw X-Microsoft-Exchange-Diagnostics: 1;BYAPR07MB4375;6:eJEtdl1RSOd95B3cWhLM1db5jmx+fKbuaSfxQaL4rPln+FMRv9iR/wAJ0A/hZugAlpPNOxQw+PBTcsr+QsCy4vnxB7F/EJgcYVO9k44LxLetbUeTXBzkCfFRdux0252Dp5MgrYeDfldnKJ+Ok9PVL1aWe4SRH98Q/QwzubeSIwDmSR8qTjLWBfvUd9SEWErd2ZFknadoBcTDti2iHQkcZPaN+XSUyr6tunYL9F6yyQna1B642ZWPCNglvKYLTyJ2b8DNwldMEGXsFFCGdHUcOSeuf1v5WbmkFU8U6kj45eUmwi80lTBbZZK5Z6QqzQPl5b97sRjQsTpAckgU1ePTFOUgodP02Zw90QGl9BWaVzN4iFyq89Tj61hLpcdb2/eEVc7LdMJUhawtCW3sA/UQvLx2XbqFftHO9fIhKIoWUrTdISa2+W4/tCSvpi6zSGBhbEhWHDQUlx8gkuuvRM45jw==;5:gid5Ljm8HFLSutUZrRKgYFRg7mQTIW3SfgJoizecmZbZJdJFrrNZUg/l/lGT+oppU7DJ4Ep57OEYmXpxyHB0t6caGbkbSMMcwOFYf8rGlJ/pV5PBIqxBXlHpD3fRngTnBnumbLmJBx5CgF1SutGqP400GXAA06wLjH8Nf0CiaPs=;24:0MeVrt2mg3fs0jASmtC5QkGKflSP/uU64z7/ItI9QX75lyn8+BfwbbGV38mKc9uIZZhQn4n8kj87lhvS2h7eNuFbGveSIc4ObwRK9beP89M= SpamDiagnosticOutput: 1:99 SpamDiagnosticMetadata: NSPM X-Microsoft-Exchange-Diagnostics: 1;BYAPR07MB4375;7:f3nHF4iTdXKGXIo7pmnATMG3ewoLmcw8R86H1JRfXtFRLvE1RLK+20t/HpU0m0+zukQ7R9VypaEbt1EiTthjIEC8uKDl0KeObJFGLxjEWz9FZNWdMbt7jRVZbEc2EaDMWbwlu9McLCPZy8H76wxd359AztLyHbmI4QZwP/FO0GK5PNLXNO5Fz/3bUcqbvz1ewVJLmT1x+HYnTpKOq9uEK1f5ka3Qd8EXyJ40/3bOyXJfm28mTWF9ijzUPGNnBe15 X-MS-Office365-Filtering-Correlation-Id: fb007330-a060-405d-c6c3-08d5a6e2f39e X-OriginatorOrg: caviumnetworks.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 20 Apr 2018 17:20:01.6788 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: fb007330-a060-405d-c6c3-08d5a6e2f39e X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 711e4ccf-2e9b-4bcf-a551-4094005b6194 X-MS-Exchange-Transport-CrossTenantHeadersStamped: BYAPR07MB4375 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org test_find_first_bit() is intentionally sub-optimal, and may cause soft lockup due to long time of run on some systems. So decrease length of bitmap to traverse to avoid lockup. With the change below, time of test execution doesn't exceed 0.2 seconds on my testing system. Signed-off-by: Yury Norov Reported-by: Fengguang Wu Fixes: 4441fca0a27f5 ("lib: test module for find_*_bit() functions") --- lib/find_bit_benchmark.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/lib/find_bit_benchmark.c b/lib/find_bit_benchmark.c index 5985a25e6cbc..5367ffa5c18f 100644 --- a/lib/find_bit_benchmark.c +++ b/lib/find_bit_benchmark.c @@ -132,7 +132,12 @@ static int __init find_bit_test(void) test_find_next_bit(bitmap, BITMAP_LEN); test_find_next_zero_bit(bitmap, BITMAP_LEN); test_find_last_bit(bitmap, BITMAP_LEN); - test_find_first_bit(bitmap, BITMAP_LEN); + + /* + * test_find_first_bit() may take some time, so + * traverse only part of bitmap to avoid soft lockup. + */ + test_find_first_bit(bitmap, BITMAP_LEN / 10); test_find_next_and_bit(bitmap, bitmap2, BITMAP_LEN); pr_err("\nStart testing find_bit() with sparse bitmap\n"); -- 2.14.1