From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from verein.lst.de ([213.95.11.211]:51487 "EHLO newverein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S936287AbdD1Ol5 (ORCPT ); Fri, 28 Apr 2017 10:41:57 -0400 Date: Fri, 28 Apr 2017 16:41:55 +0200 From: Christoph Hellwig To: Jens Axboe Cc: linux-block@vger.kernel.org, ming.lei@redhat.com, hch@lst.de Subject: Re: [PATCH 4/6] blk-mq: don't bypass scheduler for reserved requests Message-ID: <20170428144155.GD1443@lst.de> References: <1493389911-19512-1-git-send-email-axboe@fb.com> <1493389911-19512-5-git-send-email-axboe@fb.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <1493389911-19512-5-git-send-email-axboe@fb.com> Sender: linux-block-owner@vger.kernel.org List-Id: linux-block@vger.kernel.org On Fri, Apr 28, 2017 at 08:31:49AM -0600, Jens Axboe wrote: > Instead of bypassing the scheduler for insertion of reserved requests, > we ensure that the request is marked as RQF_RESERVED so they driver > knows where it came from. > > Usually we just use the tag to know if it's reserved or not, > but that only works when the request has a driver tag assigned. > Using RQF_RESERVED can be done independently of whether or not > scheduling is used. Do we really need a flag for this? If anyone cares if a request is internal it can just check ->tag / ->internal_tag is smaller than ->nr_reserved_tags using a little helper. I'd really like to keep the number of flags down as much as possible.