From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Moyer Subject: Re: [RFC PATCH 1/5] block, ioprio: include caching advice via ionice Date: Wed, 29 Oct 2014 15:02:42 -0400 Message-ID: References: <20141029180454.4879.75088.stgit@stg-AndroidDev-VirtualBox> <20141029182345.4879.98373.stgit@stg-AndroidDev-VirtualBox> Mime-Version: 1.0 Content-Type: text/plain Return-path: Received: from mx1.redhat.com ([209.132.183.28]:40784 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756619AbaJ2TCs (ORCPT ); Wed, 29 Oct 2014 15:02:48 -0400 In-Reply-To: <20141029182345.4879.98373.stgit@stg-AndroidDev-VirtualBox> (Jason B. Akers's message of "Wed, 29 Oct 2014 11:23:45 -0700") Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: "Jason B. Akers" Cc: linux-ide@vger.kernel.org, axboe@fb.com, kapil.karkra@intel.com, dan.j.williams@intel.com, linux-kernel@vger.kernel.org "Jason B. Akers" writes: > From: Dan Williams > > Steal one unused bit from the priority class and two bits from the > priority data, to implement a 3 bit cache-advice field. Similar to the > page cache advice from fadvise() these hints are meant to be consumed > by hybrid drives. Solid State Hyrbid-Drives, as defined by the SATA-IO > Specification, implement up to a 4-bit cache priority that can be > specified along with a FPDMA command. ionice is about setting an I/O scheduling class for a *process*. So, unless I've missed something, this does not seem like the right interface for passing I/O hints. You mention fadvise hints, which sounds like a good fit (and madvise would be equally interesting), but I don't see where you've wired them up in this patch set. Did I miss it? Cheers, Jeff