From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752983AbaGQScF (ORCPT ); Thu, 17 Jul 2014 14:32:05 -0400 Received: from mx1.redhat.com ([209.132.183.28]:13456 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752407AbaGQScD (ORCPT ); Thu, 17 Jul 2014 14:32:03 -0400 From: Jeff Moyer To: Akinobu Mita Cc: linux-kernel@vger.kernel.org, Andrew Morton , Jens Axboe , Alexander Viro , linux-fsdevel@vger.kernel.org Subject: Re: [PATCH] block_dev: implement readpages() to optimize sequential read References: <1405606659-3802-1-git-send-email-akinobu.mita@gmail.com> X-PGP-KeyID: 1F78E1B4 X-PGP-CertKey: F6FE 280D 8293 F72C 65FD 5A58 1FF8 A7CA 1F78 E1B4 X-PCLoadLetter: What the f**k does that mean? Date: Thu, 17 Jul 2014 14:31:56 -0400 In-Reply-To: <1405606659-3802-1-git-send-email-akinobu.mita@gmail.com> (Akinobu Mita's message of "Thu, 17 Jul 2014 23:17:39 +0900") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.3 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Akinobu Mita writes: > Sequential read from a block device is expected to be equal or faster > than from the file on a filesystem. But it is not correct due to the > lack of effective readpages() in the address space operations for > block device. Ah, a trip down memory lane. ;-) Here's a thread showing issues with the last time this was proposed (by me, incidentally): https://lkml.org/lkml/2009/6/2/480 At the very least, we need to see numbers on a real device, and see it booted on something with >4k page size before taking this back in. Cheers, Jeff