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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5B459C4332F for ; Thu, 9 Dec 2021 14:43:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238856AbhLIOqy (ORCPT ); Thu, 9 Dec 2021 09:46:54 -0500 Received: from frasgout.his.huawei.com ([185.176.79.56]:4239 "EHLO frasgout.his.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233886AbhLIOqx (ORCPT ); Thu, 9 Dec 2021 09:46:53 -0500 Received: from fraeml702-chm.china.huawei.com (unknown [172.18.147.200]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4J8xVt5szMz67sxC; Thu, 9 Dec 2021 22:39:02 +0800 (CST) Received: from lhreml724-chm.china.huawei.com (10.201.108.75) by fraeml702-chm.china.huawei.com (10.206.15.51) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2308.20; Thu, 9 Dec 2021 15:43:17 +0100 Received: from [10.47.91.245] (10.47.91.245) 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 15.1.2308.20; Thu, 9 Dec 2021 14:43:17 +0000 From: John Garry Subject: Re: [PATCH v2] blk-mq: Fix blk_mq_tagset_busy_iter() for shared tags To: Kashyap Desai , Jens Axboe CC: , , , , References: <1634550083-202815-1-git-send-email-john.garry@huawei.com> <163482611742.37241.15630114014516067630.b4-ty@kernel.dk> <0b928f7dbc2f3244afe8a475b547157f@mail.gmail.com> Message-ID: <3389cd7b-2934-8e82-b09a-a4fdb0f00ea3@huawei.com> Date: Thu, 9 Dec 2021 14:42:55 +0000 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: <0b928f7dbc2f3244afe8a475b547157f@mail.gmail.com> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.47.91.245] X-ClientProxiedBy: lhreml724-chm.china.huawei.com (10.201.108.75) 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 On 09/12/2021 13:52, Kashyap Desai wrote: > + scsi mailing list > >> On Mon, 18 Oct 2021 17:41:23 +0800, John Garry wrote: >>> Since it is now possible for a tagset to share a single set of tags, >>> the iter function should not re-iter the tags for the count of #hw >>> queues in that case. Rather it should just iter once. > John - Recently we found issue of error hander thread never kicked off and > this patch fix the issue. > Without this patch, scsi error hander will not find correct host_busy > counter. > > Take one simple case. There is one IO outstanding and that is getting > timedout. > Now SML wants to wake up EH thread only if, below condition met > "scsi_host_busy(shost) == shost->host_failed" > > Without this patch, shared host tag enabled meagaraid_sas driver will find > host_busy = actual outstanding * nr_hw_queues. > Error handler thread will never be kicked-off. > > This patch is mandatory for fixing shared host tag feature and require to be > part of stable kernel. > > Do you need more data for posting to stable kernel ? To be clear, are you saying that you see the issue which patch "blk-mq: Fix blk_mq_tagset_busy_iter() for shared tags" fixes before v5.16-rc? This patch (now commit 0994c64eb415) and the commit which it is supposed to fix, e155b0c238b2, will only be in v5.16, so I don't see anything which is needed in stable. Thanks, John