From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Mon, 29 Jan 2018 15:40:31 -0500 From: Mike Snitzer To: Ming Lei Cc: lsf-pc@lists.linux-foundation.org, Linux-scsi@vger.kernel.org, linux-block@vger.kernel.org, linux-nvme@lists.infradead.org Subject: Re: [LSF/MM TOPIC] Two blk-mq related topics Message-ID: <20180129204031.GA5499@redhat.com> References: <20180129154455.GB17176@ming.t460p> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20180129154455.GB17176@ming.t460p> Sender: linux-scsi-owner@vger.kernel.org List-ID: On Mon, Jan 29 2018 at 10:46am -0500, Ming Lei wrote: > 2. When to enable SCSI_MQ at default again? > > SCSI_MQ is enabled on V3.17 firstly, but disabled at default. In V4.13-rc1, > it is enabled at default, but later the patch is reverted in V4.13-rc7, and > becomes disabled at default too. > > Now both the original reported PM issue(actually SCSI quiesce) and the > sequential IO performance issue have been addressed. And MQ IO schedulers > are ready too for traditional disks. Are there other issues to be addressed > for enabling SCSI_MQ at default? When can we do that again? > > Last time, the two issues were reported during V4.13 dev cycle just when it is > enabled at default, that seems if SCSI_MQ isn't enabled at default, it wouldn't > be exposed to run/tested completely & fully. > > So if we continue to disable it at default, maybe it can never be exposed to > full test/production environment. I was going to propose revisiting this as well. I'd really like to see all the old .request_fn block core code removed. But maybe we take a first step of enabling: CONFIG_SCSI_MQ_DEFAULT=Y CONFIG_DM_MQ_DEFAULT=Y Thanks, Mike