From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f199.google.com (mail-pf0-f199.google.com [209.85.192.199]) by kanga.kvack.org (Postfix) with ESMTP id F1C406B0069 for ; Mon, 7 Nov 2016 10:02:10 -0500 (EST) Received: by mail-pf0-f199.google.com with SMTP id y68so51438690pfb.6 for ; Mon, 07 Nov 2016 07:02:10 -0800 (PST) Received: from bombadil.infradead.org (bombadil.infradead.org. [2001:1868:205::9]) by mx.google.com with ESMTPS id 3si31769028pfd.50.2016.11.07.07.02.10 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 07 Nov 2016 07:02:10 -0800 (PST) Date: Mon, 7 Nov 2016 07:01:03 -0800 From: Christoph Hellwig Subject: Re: [PATCHv3 15/41] filemap: handle huge pages in do_generic_file_read() Message-ID: <20161107150103.GA17451@infradead.org> References: <20160915115523.29737-1-kirill.shutemov@linux.intel.com> <20160915115523.29737-16-kirill.shutemov@linux.intel.com> <20161013093313.GB26241@quack2.suse.cz> <20161031181035.GA7007@node.shutemov.name> <20161101163940.GA5459@quack2.suse.cz> <20161102143612.GA4790@infradead.org> <20161107111305.GB13280@node.shutemov.name> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20161107111305.GB13280@node.shutemov.name> Sender: owner-linux-mm@kvack.org List-ID: To: "Kirill A. Shutemov" Cc: Christoph Hellwig , Jan Kara , "Kirill A. Shutemov" , Theodore Ts'o , Andreas Dilger , Jan Kara , Andrew Morton , Alexander Viro , Hugh Dickins , Andrea Arcangeli , Dave Hansen , Vlastimil Babka , Matthew Wilcox , Ross Zwisler , linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-block@vger.kernel.org On Mon, Nov 07, 2016 at 02:13:05PM +0300, Kirill A. Shutemov wrote: > It looks like a huge limitation to me. The DAX PMD fault code can live just fine with it. And without it performance would suck anyway. > I'm looking onto iomap_write_actor(): we still calculate 'offset' and > 'bytes' based on PAGE_SIZE before we even get the page. > This way we limit outself to PAGE_SIZE per-iteration. Of course it does, given that it does not support huge pages _yet_. But the important part is that this is now isolate to the highlevel code, and the fs can get iomap_begin calls for a huge page (or in fact much larger sizes than that). -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org