Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753005AbbG2Hd5 (ORCPT ); Wed, 29 Jul 2015 03:33:57 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:59793 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751002AbbG2Hdz (ORCPT ); Wed, 29 Jul 2015 03:33:55 -0400 MIME-Version: 1.0 In-Reply-To: <20150727173331.GA17594@infradead.org> References: <1437061068-26118-1-git-send-email-ming.lei@canonical.com> <1437061068-26118-5-git-send-email-ming.lei@canonical.com> <20150727084020.GA28336@infradead.org> <20150727094530.GA15507@infradead.org> <20150727173331.GA17594@infradead.org> Date: Wed, 29 Jul 2015 03:33:52 -0400 Message-ID: Subject: Re: [PATCH v7 4/6] block: loop: prepare for supporing direct IO From: Ming Lei To: Christoph Hellwig Cc: Dave Chinner , Jens Axboe , Linux Kernel Mailing List , "Justin M. Forbes" , Jeff Moyer , Tejun Heo , linux-api@vger.kernel.org Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1533 Lines: 41 On Mon, Jul 27, 2015 at 1:33 PM, Christoph Hellwig wrote: > On Mon, Jul 27, 2015 at 05:53:33AM -0400, Ming Lei wrote: >> Because size has to be 4k aligned too. > > Yes. But again I don't see any reason to limit us to a hardcoded 512 > byte block size here, especially considering the patches to finally >From loop block's view, the request size can be any count of 512-byte sectors, then the transfer size to backing device can't guarantee to be 4k aligned always. > allow enabling other block sizes from userspace. I have some questions about the patchset, and looks the author doesn't reply it yet. On Mon, Jul 27, 2015 at 6:06 PM, Dave Chinner wrote: >> Because size has to be 4k aligned too. > > So check that, too. Any >= 4k block size filesystem should be doing > mostly 4k aligned and sized IO... I guess you mean we only use direct IO for the 4k aligned and sized IO? If so, that won't be efficient because the page cache has to be flushed during the switch. Thanks, Ming > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/