From patchwork Fri Jul 22 12:19:36 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jan Kara X-Patchwork-Id: 9243469 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 3E3B6602F0 for ; Fri, 22 Jul 2016 12:20:17 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 2E89E266F3 for ; Fri, 22 Jul 2016 12:20:17 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 231EF27FA3; Fri, 22 Jul 2016 12:20:17 +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=unavailable 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 A7E75266F3 for ; Fri, 22 Jul 2016 12:20:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753987AbcGVMUD (ORCPT ); Fri, 22 Jul 2016 08:20:03 -0400 Received: from mx2.suse.de ([195.135.220.15]:49629 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753887AbcGVMTz (ORCPT ); Fri, 22 Jul 2016 08:19:55 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (charybdis-ext.suse.de [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 1C2CBAD77; Fri, 22 Jul 2016 12:19:51 +0000 (UTC) Received: by quack2.suse.cz (Postfix, from userid 1000) id AD6971E0F2A; Fri, 22 Jul 2016 14:19:47 +0200 (CEST) From: Jan Kara To: linux-mm@kvack.org Cc: linux-fsdevel@vger.kernel.org, linux-nvdimm@lists.01.org, Dan Williams , Ross Zwisler , Jan Kara Subject: [PATCH 10/15] mm: Factor out common parts of write fault handling Date: Fri, 22 Jul 2016 14:19:36 +0200 Message-Id: <1469189981-19000-11-git-send-email-jack@suse.cz> X-Mailer: git-send-email 2.6.6 In-Reply-To: <1469189981-19000-1-git-send-email-jack@suse.cz> References: <1469189981-19000-1-git-send-email-jack@suse.cz> Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Currently we duplicate handling of shared write faults in wp_page_reuse() and do_shared_fault(). Factor them out into a common function. Signed-off-by: Jan Kara --- mm/memory.c | 78 +++++++++++++++++++++++++++++-------------------------------- 1 file changed, 37 insertions(+), 41 deletions(-) diff --git a/mm/memory.c b/mm/memory.c index 61902a5b75c2..56b5fe8421a9 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -2059,6 +2059,41 @@ static int do_page_mkwrite(struct vm_area_struct *vma, struct page *page, } /* + * Handle dirtying of a page in shared file mapping on a write fault. + * + * The function expects the page to be locked and unlocks it. + */ +static void fault_dirty_shared_page(struct vm_area_struct *vma, + struct page *page) +{ + struct address_space *mapping; + bool dirtied; + bool page_mkwrite = vma->vm_ops->page_mkwrite; + + dirtied = set_page_dirty(page); + VM_BUG_ON_PAGE(PageAnon(page), page); + /* + * Take a local copy of the address_space - page.mapping may be zeroed + * by truncate after unlock_page(). The address_space itself remains + * pinned by vma->vm_file's reference. We rely on unlock_page()'s + * release semantics to prevent the compiler from undoing this copying. + */ + mapping = page_rmapping(page); + unlock_page(page); + + if ((dirtied || page_mkwrite) && mapping) { + /* + * Some device drivers do not set page.mapping + * but still dirty their pages + */ + balance_dirty_pages_ratelimited(mapping); + } + + if (!page_mkwrite) + file_update_time(vma->vm_file); +} + +/* * Handle write page faults for pages that can be reused in the current vma * * This can happen either due to the mapping being with the VM_SHARED flag, @@ -2090,28 +2125,11 @@ static inline int wp_page_reuse(struct mm_struct *mm, pte_unmap_unlock(page_table, ptl); if (dirty_shared) { - struct address_space *mapping; - int dirtied; - if (!page_mkwrite) lock_page(page); - dirtied = set_page_dirty(page); - VM_BUG_ON_PAGE(PageAnon(page), page); - mapping = page->mapping; - unlock_page(page); + fault_dirty_shared_page(vma, page); put_page(page); - - if ((dirtied || page_mkwrite) && mapping) { - /* - * Some device drivers do not set page.mapping - * but still dirty their pages - */ - balance_dirty_pages_ratelimited(mapping); - } - - if (!page_mkwrite) - file_update_time(vma->vm_file); } return VM_FAULT_WRITE; @@ -3125,9 +3143,7 @@ uncharge_out: static int do_shared_fault(struct mm_struct *mm, struct vm_area_struct *vma, struct vm_fault *vmf) { - struct address_space *mapping; unsigned long address = (unsigned long)vmf->virtual_address; - int dirtied = 0; int ret, tmp; ret = __do_fault(vma, vmf); @@ -3155,27 +3171,7 @@ static int do_shared_fault(struct mm_struct *mm, struct vm_area_struct *vma, return ret; } - if (set_page_dirty(vmf->page)) - dirtied = 1; - /* - * Take a local copy of the address_space - page.mapping may be zeroed - * by truncate after unlock_page(). The address_space itself remains - * pinned by vma->vm_file's reference. We rely on unlock_page()'s - * release semantics to prevent the compiler from undoing this copying. - */ - mapping = page_rmapping(vmf->page); - unlock_page(vmf->page); - if ((dirtied || vma->vm_ops->page_mkwrite) && mapping) { - /* - * Some device drivers do not set page.mapping but still - * dirty their pages - */ - balance_dirty_pages_ratelimited(mapping); - } - - if (!vma->vm_ops->page_mkwrite) - file_update_time(vma->vm_file); - + fault_dirty_shared_page(vma, vmf->page); return ret; }