Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S966520AbcLVRMm (ORCPT ); Thu, 22 Dec 2016 12:12:42 -0500 Received: from mail-pg0-f42.google.com ([74.125.83.42]:34311 "EHLO mail-pg0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1762052AbcLVRMk (ORCPT ); Thu, 22 Dec 2016 12:12:40 -0500 Date: Thu, 22 Dec 2016 09:12:24 -0800 From: Omar Sandoval To: Bart Van Assche Cc: "linux-kernel@vger.kernel.org" , "linux-block@vger.kernel.org" , "osandov@fb.com" , "axboe@fb.com" , "axboe@kernel.dk" , "paolo.valente@linaro.org" Subject: Re: [PATCHSET v4] blk-mq-scheduling framework Message-ID: <20161222171224.GA26830@vader> References: <1481933536-12844-1-git-send-email-axboe@fb.com> <1482423775.2682.6.camel@sandisk.com> <20161222165207.GA25717@vader> <1482425838.2682.9.camel@sandisk.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1482425838.2682.9.camel@sandisk.com> User-Agent: Mutt/1.7.2 (2016-11-26) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 744 Lines: 17 On Thu, Dec 22, 2016 at 04:57:36PM +0000, Bart Van Assche wrote: > On Thu, 2016-12-22 at 08:52 -0800, Omar Sandoval wrote: > > This approach occurred to us, but we couldn't figure out a way to make > > blk_mq_tag_to_rq() work with it. From skimming over the patches, I > > didn't see a solution to that problem. > > Hello Omar, > > Can you clarify your comment? Since my patches initialize both tags->rqs[] > and sched_tags->rqs[] the function blk_mq_tag_to_rq() should still work. > > Bart. Sorry, you're right, it does work, but tags->rqs[] ends up being the extra lookup table. I suspect that the runtime overhead of keeping that up to date could be worse than copying the rq fields if you have lots of CPUs but only one hardware queue.