From patchwork Tue Nov 29 11:22:36 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Kirill A . Shutemov" X-Patchwork-Id: 9451545 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 74C6960710 for ; Tue, 29 Nov 2016 11:26:00 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 581E1281B7 for ; Tue, 29 Nov 2016 11:26:00 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 4CD55281E1; Tue, 29 Nov 2016 11:26:00 +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 DFD3C281D2 for ; Tue, 29 Nov 2016 11:25:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933318AbcK2LZx (ORCPT ); Tue, 29 Nov 2016 06:25:53 -0500 Received: from mga11.intel.com ([192.55.52.93]:52808 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757311AbcK2LX4 (ORCPT ); Tue, 29 Nov 2016 06:23:56 -0500 Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by fmsmga102.fm.intel.com with ESMTP; 29 Nov 2016 03:23:56 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.31,568,1473145200"; d="scan'208";a="1091991778" Received: from black.fi.intel.com ([10.237.72.28]) by fmsmga002.fm.intel.com with ESMTP; 29 Nov 2016 03:23:52 -0800 Received: by black.fi.intel.com (Postfix, from userid 1000) id 4900D689; Tue, 29 Nov 2016 13:23:12 +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: [PATCHv5 08/36] filemap: handle huge pages in do_generic_file_read() Date: Tue, 29 Nov 2016 14:22:36 +0300 Message-Id: <20161129112304.90056-9-kirill.shutemov@linux.intel.com> X-Mailer: git-send-email 2.10.2 In-Reply-To: <20161129112304.90056-1-kirill.shutemov@linux.intel.com> References: <20161129112304.90056-1-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 74341f8b831e..6a2f9ea521fb 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -1749,6 +1749,7 @@ 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, @@ -1830,7 +1831,8 @@ 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; @@ -2248,6 +2250,7 @@ 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) {