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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 28C9FC00140 for ; Wed, 10 Aug 2022 08:33:31 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id BE16D8E0003; Wed, 10 Aug 2022 04:33:30 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id B90698E0001; Wed, 10 Aug 2022 04:33:30 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id A587F8E0003; Wed, 10 Aug 2022 04:33:30 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id 96CF18E0001 for ; Wed, 10 Aug 2022 04:33:30 -0400 (EDT) Received: from smtpin26.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay03.hostedemail.com (Postfix) with ESMTP id 4D6F9A1101 for ; Wed, 10 Aug 2022 08:33:30 +0000 (UTC) X-FDA: 79783018980.26.7FFE660 Received: from frasgout.his.huawei.com (frasgout.his.huawei.com [185.176.79.56]) by imf03.hostedemail.com (Postfix) with ESMTP id 9488E20171 for ; Wed, 10 Aug 2022 08:33:29 +0000 (UTC) Received: from fraeml701-chm.china.huawei.com (unknown [172.18.147.200]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4M2jrM3KsSz67Xgw; Wed, 10 Aug 2022 16:33:23 +0800 (CST) Received: from lhrpeml500003.china.huawei.com (7.191.162.67) by fraeml701-chm.china.huawei.com (10.206.15.50) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2375.24; Wed, 10 Aug 2022 10:33:27 +0200 Received: from [10.195.247.138] (10.195.247.138) by lhrpeml500003.china.huawei.com (7.191.162.67) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Wed, 10 Aug 2022 09:33:24 +0100 Message-ID: <82dbf4d6-2d43-20ff-22a7-857f9f11a5ce@huawei.com> Date: Wed, 10 Aug 2022 09:33:23 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.6.1 Subject: Re: [ata] 0568e61225: stress-ng.copy-file.ops_per_sec -15.0% regression To: Damien Le Moal , kernel test robot CC: Christoph Hellwig , "Martin K. Petersen" , LKML , "Linux Memory Management List" , , , , , , , References: <1f498d4a-f93f-ceb4-b713-753196e5e08d@opensource.wdc.com> <3451fa5a-6229-073f-ae18-0c232cd48ed5@huawei.com> <16f03f81-a8c7-bacf-c74c-67231f7f7202@huawei.com> From: John Garry In-Reply-To: Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [10.195.247.138] X-ClientProxiedBy: lhrpeml500005.china.huawei.com (7.191.163.240) To lhrpeml500003.china.huawei.com (7.191.162.67) X-CFilter-Loop: Reflected ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1660120410; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=1z1HHUmmc9ehzLd3tfEymiNccHq3ja5eQ1QQmYYH2Pw=; b=jj7/hoATWmkZS4eurdsa6A+6xfjiWInMIwldX8sU2euBSi0UeBo9W1cmT/Iz2hGBSEM9xm cgTsAQwJxQ9VJ4iRVriNiSuX66kceoayg2d35GBd+hlHWM7uYIjRI17fqDgVji1guihc/a 0EjJ98DeXnNc69d/oFLTD0K6OzH/OBo= ARC-Authentication-Results: i=1; imf03.hostedemail.com; dkim=none; dmarc=pass (policy=quarantine) header.from=huawei.com; spf=pass (imf03.hostedemail.com: domain of john.garry@huawei.com designates 185.176.79.56 as permitted sender) smtp.mailfrom=john.garry@huawei.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1660120410; a=rsa-sha256; cv=none; b=ApeZKBqtACMFl8rCy0iuwg/Ncj+/1Z6novjw6/LFT/aMLpotVXk1t3fjIR/OnnmSkdhLw9 wormsh34uQVn1JCXtUsffbFTYlG4k+5g3ygbM6X9K6aBumP9IoMsz+amBMzZYxfMdZK/Lq /MyQm9msd2bf43dJboFTik6f4OFJ18s= X-Rspamd-Queue-Id: 9488E20171 Authentication-Results: imf03.hostedemail.com; dkim=none; dmarc=pass (policy=quarantine) header.from=huawei.com; spf=pass (imf03.hostedemail.com: domain of john.garry@huawei.com designates 185.176.79.56 as permitted sender) smtp.mailfrom=john.garry@huawei.com X-Rspam-User: X-Rspamd-Server: rspam07 X-Stat-Signature: 1st3pgscdhaj419i65j61phocm5xbnqj X-HE-Tag: 1660120409-815324 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 09/08/2022 15:57, Damien Le Moal wrote: >>> As far as I can see, this patch should not make a difference unless the >>> ATA shost driver is setting the max_sectors value unnecessarily low. >> For __ATA_BASE_SHT, we don't set max_sectors. As such, we default >> shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS (=1024) in >> scsi_host_alloc(). I assume no shost dma mapping limit applied. >> >> Then - for example - we could select dev->max_sectors = >> ATA_MAX_SECTORS_LBA48 (=65535) in ata_dev_configure(). >> >> So with commit 0568e6122574 we would have final max sectors = 1024, as >> opposed to 65535 previously. I guess that the problem is something like >> this. >> >> If so, it seems that we would need to apply the shost dma mapping limit >> separately in ata_scsi_dev_config() and not use shost->max_sectors. > OK. Will have a look at that. > We may need to introduce something like shost->max_hw_sectors, which is set according to sht max sectors and dma mapping limits. That could be also used in USB scsiglue slave_configure() Or else set max_sectors value for __ATA_BASE_SHT, but I don't know a sane value there considering ATA_MAX_SECTORS_LBA48 gives max_sectors of 65535. Damien, please let me know if you need help now. I am just waiting for you to test to prove this theory about dev->max_sectors being capped. I don't have an AHCI setup readily-available for testing - just SAS cards or QEMU. Thanks, John