From patchwork Thu Jan 26 11:57:50 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Kirill A . Shutemov" X-Patchwork-Id: 9539093 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 6E611604A9 for ; Thu, 26 Jan 2017 12:06:24 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 65C6A26E91 for ; Thu, 26 Jan 2017 12:06:24 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 5A3C42818E; Thu, 26 Jan 2017 12:06:24 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 092AE281C3 for ; Thu, 26 Jan 2017 12:06:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752201AbdAZMGG (ORCPT ); Thu, 26 Jan 2017 07:06:06 -0500 Received: from mga11.intel.com ([192.55.52.93]:44267 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753275AbdAZL7H (ORCPT ); Thu, 26 Jan 2017 06:59:07 -0500 Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by fmsmga102.fm.intel.com with ESMTP; 26 Jan 2017 03:58:36 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.33,289,1477983600"; d="scan'208";a="1118089728" Received: from black.fi.intel.com ([10.237.72.28]) by fmsmga002.fm.intel.com with ESMTP; 26 Jan 2017 03:58:31 -0800 Received: by black.fi.intel.com (Postfix, from userid 1000) id 8159A1F0; Thu, 26 Jan 2017 13:58:25 +0200 (EET) From: "Kirill A. Shutemov" To: "Theodore Ts'o" , Andreas Dilger , Jan Kara , Andrew Morton Cc: 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, "Kirill A. Shutemov" Subject: [PATCHv6 08/37] filemap: handle huge pages in do_generic_file_read() Date: Thu, 26 Jan 2017 14:57:50 +0300 Message-Id: <20170126115819.58875-9-kirill.shutemov@linux.intel.com> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20170126115819.58875-1-kirill.shutemov@linux.intel.com> References: <20170126115819.58875-1-kirill.shutemov@linux.intel.com> Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Most of work happans on head page. Only when we need to do copy data to userspace we find relevant subpage. We are still limited by PAGE_SIZE per iteration. Lifting this limitation would require some more work. Signed-off-by: Kirill A. Shutemov --- mm/filemap.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/mm/filemap.c b/mm/filemap.c index 301327685a71..6cba69176ea9 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -1886,6 +1886,7 @@ static ssize_t do_generic_file_read(struct file *filp, loff_t *ppos, if (unlikely(page == NULL)) goto no_cached_page; } + page = compound_head(page); if (PageReadahead(page)) { page_cache_async_readahead(mapping, ra, filp, page, @@ -1967,7 +1968,8 @@ static ssize_t do_generic_file_read(struct file *filp, loff_t *ppos, * now we can copy it to user space... */ - ret = copy_page_to_iter(page, offset, nr, iter); + ret = copy_page_to_iter(page + index - page->index, offset, + nr, iter); offset += ret; index += offset >> PAGE_SHIFT; offset &= ~PAGE_MASK; @@ -2385,6 +2387,7 @@ int filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf) * because there really aren't any performance issues here * and we need to check for errors. */ + page = compound_head(page); ClearPageError(page); error = mapping->a_ops->readpage(file, page); if (!error) {