Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::3:7 as permitted sender) client-ip=2620:137:e000::3:7;
Message-ID: <CY8PR05MB93787EA896549E9F08766754CDF1A@CY8PR05MB9378.namprd05.prod.outlook.com>
Date:   Tue, 12 Sep 2023 14:17:13 +0800
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101
 Thunderbird/102.15.0
Content-Language: en-US
To:     djwong@kernel.org
Cc:     linux-xfs@vger.kernel.org, linux-kernel@vger.kernel.org
From:   Wang Jianchao <jianchwa@outlook.com>
Subject: PATCH] xfs: use roundup_pow_of_two in xlog_write_log_records
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 7bit
MIME-Version: 1.0
X-MS-Exchange-MessageSentRepresentingType: 1
X-MS-PublicTrafficType: Email
X-MS-TrafficTypeDiagnostic: CY8PR05MB9378:EE_|LV3PR05MB10358:EE_
X-MS-Office365-Filtering-Correlation-Id: 7b0f09f8-0cdc-4f1a-a6c0-08dbb35806c6
X-Microsoft-Antispam: BCL:0;
X-Microsoft-Antispam-Message-Info: 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
X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1
X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?ODlQY2ZkV0FNaGxkK0lEbngxT1B6Q1RPekxQUWxkTVJNSWtTN09najVVaFNH?=
 =?utf-8?B?SDhYQ3ZuV2F5NVo0YSt6ZU1vYzRWTEFzdmRKdFgwZC9qK2pOOU1TZ0gyb1Z1?=
 =?utf-8?B?dDZTaEY1VjMvME1RNlg3bTl1SVoweXZLNTAreHFFUEQ5Sm9tWlZEMEtUUnZO?=
 =?utf-8?B?YTBuQTN4L2FOeTdFQUlxWnhhZENKOGl3NVM3RENTb2xoSHpSNVBkVWpZaTdZ?=
 =?utf-8?B?VkpnN2FTMmZJUkhpelVRdVBodWJjQkFjcEZwRlpYMjJjVlJDT1dsVkxwOENl?=
 =?utf-8?B?aURsUzJ6M3FRNjhiVXkxa2pITmxubmlhaGpIeXFmeE5LRjVsa1B6QW4wbjBv?=
 =?utf-8?B?eTlkUlVuaFVwR2l0Q25xWWU2OWVjSVJUVFN4elBSVWplMlROaVByRWZHbTBW?=
 =?utf-8?B?VzdBaExwMS9wMUpGVVZMUlF6dUptMG5KNTk1ZmQ1anUxcDJ3OXlrcUNvUGVF?=
 =?utf-8?B?emZHS0V0cnhFZ2JtTlBUbFlsS28xM0hDVThnSDZZZzk5OFJUb21PQzJoWHBB?=
 =?utf-8?B?bXlRLy9WY3BPYmFXWWlFcHQ3WHNXS3dydHlNS00rYnk2SEpTZjRZNlJmV3dZ?=
 =?utf-8?B?UThSN3l3bWd2VDdmOUxjZ1c0MlJTM0xhQ0dhZmcyL0V3Um5HNWFoOU1McmNw?=
 =?utf-8?B?elBOelp6U2xIakVTTk14eGhZL2U1b29YMWdIaHZYMU9YTXBxWVhYdERNYXBX?=
 =?utf-8?B?RjljZU1jZzMrajN1cEh6Z3h6b1pBUEh5TXJOeG5ZVUZrREd4QXYvcG5vZ2N5?=
 =?utf-8?B?THVYb014VkNTNlFUcFY3OEt0UFdsOUkvd3E2dWZiVHg4VjVWSTlJbDcvZnVI?=
 =?utf-8?B?MkZwZ1IxUHFkOGNWVWVkbTIxbmhoaFcyZ0R5Zm8xR3ZubTVNZFNHemxmMjdL?=
 =?utf-8?B?dk05Z3BKNGNLZEs0VFB6aGYzaVB0aytvRytNVlAxb1pYSkdUVUt2TU9RVjdI?=
 =?utf-8?B?ZTlhM0tJL0ZTRXRzM2gzSlVDNDJnNUtST2ZFekZ4MDFNbHlSRDNKM0JJdFNh?=
 =?utf-8?B?L1ZnZWJNQnlnNDI0ZTlGcUo3dFZzalpwQ1hMVG9xazJIWUc4YlUvbEExT1di?=
 =?utf-8?B?U1IrZUdTTGR6NldFSCtNdmY1MUpNUHZxVzFhWDcxZTJRZmYyYjBFclVUb1N3?=
 =?utf-8?B?ekFyNkYzV1ljekpWKzdyQjg3dmhPTlhkd1lmbHkwODlvYmJaazJ1OWdGTUY4?=
 =?utf-8?B?VDR0RXFUNndhVzNGQ2l5R2RtME1zSUxZUkdjdVAxU0k1UU8zenExUENLS0c0?=
 =?utf-8?B?MDIwd243YWxPZHhpTzdOeFdhSjRUZTVkaXRrRGJuMEFIT3QyRWhudlFuUjdX?=
 =?utf-8?B?M25qTVNITWVjVVpoVU9ValNYbUhmYklMOTNkMEE5RW5iTXl1TEJIVVVNbUZt?=
 =?utf-8?B?SERsTkl4SXNTWnlwRlNzcHZKdFJZQXBQbXk5WWdnZlhoVXFaOTJ4UFdadGtX?=
 =?utf-8?B?YmN6TTZUdkpSZnJXbndoejBudldHa211Yk8yMGo2RkloblVsZnJFTjYyU25n?=
 =?utf-8?B?Qk5pR2xZSU1lTmtkQ3NXSDN0WVJheWRlRFNYUVA3V2R4WVZnRHVNczRlbkpD?=
 =?utf-8?B?QWM4NHp4YlQ2WVcxVU8vbXU4ZDVpOVMzMjN0NmJmYlVVc01lZEFOWVJ3SG5t?=
 =?utf-8?Q?bRdE9t/uM81ugyVHmvteY1pnL1eNwmPccLDZ+lA1n40M=3D?=
X-OriginatorOrg: outlook.com
X-MS-Exchange-CrossTenant-Network-Message-Id: 7b0f09f8-0cdc-4f1a-a6c0-08dbb35806c6
X-MS-Exchange-CrossTenant-AuthSource: CY8PR05MB9378.namprd05.prod.outlook.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 12 Sep 2023 06:18:05.8503
 (UTC)
X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted
X-MS-Exchange-CrossTenant-Id: 84df9e7f-e9f6-40af-b435-aaaaaaaaaaaa
X-MS-Exchange-CrossTenant-RMS-PersistedConsumerOrg: 00000000-0000-0000-0000-000000000000
X-MS-Exchange-Transport-CrossTenantHeadersStamped: LV3PR05MB10358
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org
X-Greylist: Sender passed SPF test, not delayed by milter-greylist-4.6.4 (snail.vger.email [0.0.0.0]); Mon, 11 Sep 2023 23:18:13 -0700 (PDT)


In our production environment, we find that mounting a 500M and
clean /boot needs ~6 seconds sometimes. The one cause is that
xlog_write_log_records() uses ffs to decide the buffer size. It
can cause a lot of small IO easily when xlog_clear_stale_blocks()
needs to wrap around the end of log area and log head block is
not power of two. As xlog_write_log_records() has handled bigger
buffer very well, we can use roundup_pow_of_two instead of ffs to
decide buffer size.

Signed-off-by: Wang Jianchao <jianchwa@outlook.com>
---
 fs/xfs/xfs_log_recover.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/xfs/xfs_log_recover.c b/fs/xfs/xfs_log_recover.c
index 82c81d20459d..9368fefe1d0a 100644
--- a/fs/xfs/xfs_log_recover.c
+++ b/fs/xfs/xfs_log_recover.c
@@ -1528,7 +1528,7 @@ xlog_write_log_records(
 	 * a smaller size.  We need to be able to write at least a
 	 * log sector, or we're out of luck.
 	 */
-	bufblks = 1 << ffs(blocks);
+	bufblks = roundup_pow_of_two(blocks);
 	while (bufblks > log->l_logBBsize)
 		bufblks >>= 1;
 	while (!(buffer = xlog_alloc_buffer(log, bufblks))) {
-- 
2.34.1