From patchwork Tue Nov 1 22:36:17 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jan Kara X-Patchwork-Id: 9408215 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 8691760722 for ; Tue, 1 Nov 2016 22:37:42 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 76F6F29B07 for ; Tue, 1 Nov 2016 22:37:42 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 6B92929B05; Tue, 1 Nov 2016 22:37:42 +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=-1.9 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_NONE autolearn=unavailable version=3.3.1 Received: from ml01.01.org (ml01.01.org [198.145.21.10]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 33C3929AFF for ; Tue, 1 Nov 2016 22:37:42 +0000 (UTC) Received: from [127.0.0.1] (localhost [IPv6:::1]) by ml01.01.org (Postfix) with ESMTP id 065CA81D4D; Tue, 1 Nov 2016 15:37:35 -0700 (PDT) X-Original-To: linux-nvdimm@lists.01.org Delivered-To: linux-nvdimm@lists.01.org Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) (using TLSv1 with cipher ECDHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id 3425881D2F for ; Tue, 1 Nov 2016 15:37:34 -0700 (PDT) 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 4FEFEAD7C; Tue, 1 Nov 2016 22:37:34 +0000 (UTC) Received: by quack2.suse.cz (Postfix, from userid 1000) id 9F49D1E0FC0; Tue, 1 Nov 2016 23:37:27 +0100 (CET) From: Jan Kara To: Subject: [PATCH 08/21] mm: Allow full handling of COW faults in ->fault handlers Date: Tue, 1 Nov 2016 23:36:17 +0100 Message-Id: <1478039794-20253-12-git-send-email-jack@suse.cz> X-Mailer: git-send-email 2.6.6 In-Reply-To: <1478039794-20253-1-git-send-email-jack@suse.cz> References: <1478039794-20253-1-git-send-email-jack@suse.cz> X-BeenThere: linux-nvdimm@lists.01.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: "Linux-nvdimm developer list." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-fsdevel@vger.kernel.org, Andrew Morton , Jan Kara , linux-nvdimm@lists.01.org MIME-Version: 1.0 Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" 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 --- 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 f8e758060851..78173d7de007 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);