From patchwork Tue Sep 27 16:08:12 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jan Kara X-Patchwork-Id: 9352275 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 7F0A7600CB for ; Tue, 27 Sep 2016 16:08:57 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 716E428979 for ; Tue, 27 Sep 2016 16:08:57 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 6628F29297; Tue, 27 Sep 2016 16:08:57 +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 5BA1E28A05 for ; Tue, 27 Sep 2016 16:08:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934435AbcI0QIv (ORCPT ); Tue, 27 Sep 2016 12:08:51 -0400 Received: from mx2.suse.de ([195.135.220.15]:37341 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751519AbcI0QIg (ORCPT ); Tue, 27 Sep 2016 12:08:36 -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 271017501A; Tue, 27 Sep 2016 16:08:32 +0000 (UTC) Received: by quack2.suse.cz (Postfix, from userid 1000) id 06AA71E10EB; Tue, 27 Sep 2016 18:08:31 +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 , "Kirill A. Shutemov" , Jan Kara Subject: [PATCH 08/20] mm: Allow full handling of COW faults in ->fault handlers Date: Tue, 27 Sep 2016 18:08:12 +0200 Message-Id: <1474992504-20133-9-git-send-email-jack@suse.cz> X-Mailer: git-send-email 2.6.6 In-Reply-To: <1474992504-20133-1-git-send-email-jack@suse.cz> References: <1474992504-20133-1-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. Signed-off-by: Jan Kara Reviewed-by: Ross Zwisler --- 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 c908fd7243ea..faa77b15e9a6 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -303,7 +303,8 @@ 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 @@ -1117,6 +1118,7 @@ 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 0c8779c23925..17db88a38e8a 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -2844,9 +2844,8 @@ 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))) { @@ -3205,9 +3204,12 @@ 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);