From: Jens Axboe Subject: Re: [GIT PULL] Ext3 latency fixes Date: Mon, 6 Apr 2009 10:13:56 +0200 Message-ID: <20090406081356.GS5178@kernel.dk> References: <20090404151649.GE5178@kernel.dk> <20090404173412.GF5178@kernel.dk> <20090404180108.GH5178@kernel.dk> <20090404232222.GA7480@mit.edu> <20090404163349.20df1208@infradead.org> <20090405001005.GA7553@mit.edu> <49D8E71F.6000703@rtr.ca> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Linus Torvalds , Theodore Tso , Arjan van de Ven , Linux Kernel Developers List , Ext4 Developers List To: Mark Lord Return-path: Received: from brick.kernel.dk ([93.163.65.50]:38543 "EHLO kernel.dk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751709AbZDFIN6 (ORCPT ); Mon, 6 Apr 2009 04:13:58 -0400 Content-Disposition: inline In-Reply-To: <49D8E71F.6000703@rtr.ca> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Sun, Apr 05 2009, Mark Lord wrote: > Linus Torvalds wrote: >> >> Non-rotational media would tend to want the unplugging, but the block >> layer already does that (ie in __make_request() we already do: >> >> if (unplug || blk_queue_nonrot(q)) >> __generic_unplug_device(q); >> >> so non-rotational devices get unplugged whether the request was a >> unplugging request or not). > .. > > Mmm.. except that Jeff's SSD doesn't appear to identify itself > as a non-rotating media. I suppose there's a way to "quirk" that > somewhere, though. You can quirk it in userspace, just have it set the 'rotational' sysfs file to 0 if it matches make/model/whatever. -- Jens Axboe