From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Fri, 19 Jan 2018 23:33:33 +0800 From: Ming Lei To: Bart Van Assche Cc: "axboe@kernel.dk" , "dm-devel@redhat.com" , "hch@infradead.org" , "linux-kernel@vger.kernel.org" , "linux-block@vger.kernel.org" , "osandov@fb.com" , "snitzer@redhat.com" Subject: Re: [RFC PATCH] blk-mq: fixup RESTART when queue becomes idle Message-ID: <20180119153333.GA14827@ming.t460p> References: <20180118170353.GB19734@redhat.com> <1516296056.2676.23.camel@wdc.com> <20180118183039.GA20121@redhat.com> <1516301278.2676.35.camel@wdc.com> <20180119023212.GA25413@ming.t460p> <20180119072623.GB25369@ming.t460p> <1516375212.3190.4.camel@wdc.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <1516375212.3190.4.camel@wdc.com> List-ID: On Fri, Jan 19, 2018 at 03:20:13PM +0000, Bart Van Assche wrote: > On Fri, 2018-01-19 at 15:26 +0800, Ming Lei wrote: > > Please see queue_delayed_work_on(), hctx->run_work is shared by all > > scheduling, once blk_mq_delay_run_hw_queue(100ms) returns, no new > > scheduling can make progress during the 100ms. > > How about addressing that as follows: > > diff --git a/block/blk-mq.c b/block/blk-mq.c > index f7515dd95a36..57f8379a476d 100644 > --- a/block/blk-mq.c > +++ b/block/blk-mq.c > @@ -1403,9 +1403,9 @@ static void __blk_mq_delay_run_hw_queue(struct blk_mq_hw_ctx *hctx, bool async, > put_cpu(); > } > > - kblockd_schedule_delayed_work_on(blk_mq_hctx_next_cpu(hctx), > - &hctx->run_work, > - msecs_to_jiffies(msecs)); > + kblockd_mod_delayed_work_on(blk_mq_hctx_next_cpu(hctx), > + &hctx->run_work, > + msecs_to_jiffies(msecs)); > } > > void blk_mq_delay_run_hw_queue(struct blk_mq_hw_ctx *hctx, unsigned long msecs) > > Bart. Yes, this one together with Jen's suggestion with returning BLK_STS_NO_DEV_RESOURCE should fix this issue. Could you cook a fix for this issue? Otherwise I am happy to do that. -- Ming