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=-15.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 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 96851C4320A for ; Wed, 11 Aug 2021 10:31:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 74E5560E52 for ; Wed, 11 Aug 2021 10:31:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237199AbhHKKcN (ORCPT ); Wed, 11 Aug 2021 06:32:13 -0400 Received: from frasgout.his.huawei.com ([185.176.79.56]:3624 "EHLO frasgout.his.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236935AbhHKKcL (ORCPT ); Wed, 11 Aug 2021 06:32:11 -0400 Received: from fraeml735-chm.china.huawei.com (unknown [172.18.147.201]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4Gl5hK69ZTz6BDkl; Wed, 11 Aug 2021 18:31:13 +0800 (CST) Received: from lhreml724-chm.china.huawei.com (10.201.108.75) by fraeml735-chm.china.huawei.com (10.206.15.216) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.8; Wed, 11 Aug 2021 12:31:46 +0200 Received: from [10.47.80.4] (10.47.80.4) by lhreml724-chm.china.huawei.com (10.201.108.75) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2176.2; Wed, 11 Aug 2021 11:31:45 +0100 Subject: Re: [PATCH RFC 2/8] iommu/arm-smmu-v3: Add and use static helper function arm_smmu_cmdq_issue_cmd_with_sync() To: Will Deacon , "Leizhen (ThunderTown)" CC: Robin Murphy , iommu , linux-arm-kernel , linux-kernel References: <20210626110130.2416-1-thunder.leizhen@huawei.com> <20210626110130.2416-3-thunder.leizhen@huawei.com> <20210810182454.GB3296@willie-the-truck> <20210811100905.GB4426@willie-the-truck> From: John Garry Message-ID: Date: Wed, 11 Aug 2021 11:31:08 +0100 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.12.1 MIME-Version: 1.0 In-Reply-To: <20210811100905.GB4426@willie-the-truck> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.47.80.4] X-ClientProxiedBy: lhreml712-chm.china.huawei.com (10.201.108.63) To lhreml724-chm.china.huawei.com (10.201.108.75) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org >>>> Obviously, inserting as many commands at a time as possible can reduce the >>>> number of times the mutex contention participates, thereby improving the >>>> overall performance. At least it reduces the number of calls to function >>>> arm_smmu_cmdq_issue_cmdlist(). >>>> >>>> Therefore, function arm_smmu_cmdq_issue_cmd_with_sync() is added to insert >>>> the 'cmd+sync' commands at a time. >>>> >>>> Signed-off-by: Zhen Lei >>>> --- >>>> drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 33 +++++++++++++-------- >>>> 1 file changed, 21 insertions(+), 12 deletions(-) >>>> >>>> diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c >>>> index 2433d3c29b49ff2..a5361153ca1d6a4 100644 >>>> --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c >>>> +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c >>>> @@ -858,11 +858,25 @@ static int arm_smmu_cmdq_issue_cmd(struct arm_smmu_device *smmu, >>>> return arm_smmu_cmdq_issue_cmdlist(smmu, cmd, 1, false); >>>> } >>>> >>>> -static int arm_smmu_cmdq_issue_sync(struct arm_smmu_device *smmu) >>>> +static int __maybe_unused arm_smmu_cmdq_issue_sync(struct arm_smmu_device *smmu) >>>> { >>>> return arm_smmu_cmdq_issue_cmdlist(smmu, NULL, 0, true); >>>> } >>>> >>>> +static int arm_smmu_cmdq_issue_cmd_with_sync(struct arm_smmu_device *smmu, >>>> + struct arm_smmu_cmdq_ent *ent) >>>> +{ >>>> + u64 cmd[CMDQ_ENT_DWORDS]; >>>> + >>>> + if (arm_smmu_cmdq_build_cmd(cmd, ent)) { >>>> + dev_warn(smmu->dev, "ignoring unknown CMDQ opcode 0x%x\n", >>>> + ent->opcode); >>>> + return -EINVAL; Are any of the errors returned from the "issue command" functions actually consumed? I couldn't see it on mainline code from a brief browse. >>>> + } >>>> + >>>> + return arm_smmu_cmdq_issue_cmdlist(smmu, cmd, 1, true); Thanks, John