From patchwork Fri Nov 4 04:25:04 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jan Kara X-Patchwork-Id: 9411889 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 6FB3A60585 for ; Fri, 4 Nov 2016 04:25:58 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 5EFC22AC9E for ; Fri, 4 Nov 2016 04:25:58 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 52D902ACA4; Fri, 4 Nov 2016 04:25:58 +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 08B662AC9E for ; Fri, 4 Nov 2016 04:25:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932724AbcKDEZ4 (ORCPT ); Fri, 4 Nov 2016 00:25:56 -0400 Received: from mx2.suse.de ([195.135.220.15]:44714 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753677AbcKDEZ0 (ORCPT ); Fri, 4 Nov 2016 00:25:26 -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 A4063ACF2; Fri, 4 Nov 2016 04:25:25 +0000 (UTC) Received: by quack2.suse.cz (Postfix, from userid 1000) id A56461E0FCE; Fri, 4 Nov 2016 05:25:20 +0100 (CET) From: Jan Kara To: Cc: , linux-nvdimm@lists.01.org, Andrew Morton , Ross Zwisler , "Kirill A. Shutemov" , Jan Kara Subject: [PATCH 08/21] mm: Allow full handling of COW faults in ->fault handlers Date: Fri, 4 Nov 2016 05:25:04 +0100 Message-Id: <1478233517-3571-9-git-send-email-jack@suse.cz> X-Mailer: git-send-email 2.6.6 In-Reply-To: <1478233517-3571-1-git-send-email-jack@suse.cz> References: <1478233517-3571-1-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 To allow full handling of COW faults add memcg field to struct vm_fault and a return value of ->fault() handler meaning that COW fault is fully handled and memcg charge must not be canceled. This will allow us to remove knowledge about special DAX locking from the generic fault code. Reviewed-by: Ross Zwisler Signed-off-by: Jan Kara Acked-by: Kirill A. Shutemov --- include/linux/mm.h | 4 +++- mm/memory.c | 8 +++++--- 2 files changed, 8 insertions(+), 4 deletions(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index 5cc679b874eb..34d2891e9195 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -301,7 +301,8 @@ struct vm_fault { * the 'address' */ pte_t orig_pte; /* Value of PTE at the time of fault */ - struct page *cow_page; /* Handler may choose to COW */ + struct page *cow_page; /* Page handler may use for COW fault */ + struct mem_cgroup *memcg; /* Cgroup cow_page belongs to */ struct page *page; /* ->fault handlers should return a * page here, unless VM_FAULT_NOPAGE * is set (which is also implied by @@ -1103,6 +1104,7 @@ static inline void clear_page_pfmemalloc(struct page *page) #define VM_FAULT_RETRY 0x0400 /* ->fault blocked, must retry */ #define VM_FAULT_FALLBACK 0x0800 /* huge page fault failed, fall back to small */ #define VM_FAULT_DAX_LOCKED 0x1000 /* ->fault has locked DAX entry */ +#define VM_FAULT_DONE_COW 0x2000 /* ->fault has fully handled COW */ #define VM_FAULT_HWPOISON_LARGE_MASK 0xf000 /* encodes hpage index for large hwpoison */ diff --git a/mm/memory.c b/mm/memory.c index 25028422a578..ac901bb02398 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -2848,9 +2848,8 @@ static int __do_fault(struct vm_fault *vmf) int ret; ret = vma->vm_ops->fault(vma, vmf); - if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY))) - return ret; - if (ret & VM_FAULT_DAX_LOCKED) + if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY | + VM_FAULT_DAX_LOCKED | VM_FAULT_DONE_COW))) return ret; if (unlikely(PageHWPoison(vmf->page))) { @@ -3209,9 +3208,12 @@ static int do_cow_fault(struct vm_fault *vmf) } vmf->cow_page = new_page; + vmf->memcg = memcg; ret = __do_fault(vmf); if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY))) goto uncharge_out; + if (ret & VM_FAULT_DONE_COW) + return ret; if (!(ret & VM_FAULT_DAX_LOCKED)) copy_user_highpage(new_page, vmf->page, vmf->address, vma);