From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E899AC55199 for ; Mon, 27 Apr 2020 12:28:47 +0000 (UTC) Received: from ml01.01.org (ml01.01.org [198.145.21.10]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 21DC8206BF for ; Mon, 27 Apr 2020 12:28:47 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="h4uZN/H6" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 21DC8206BF Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-nvdimm-bounces@lists.01.org Received: from ml01.vlan13.01.org (localhost [IPv6:::1]) by ml01.01.org (Postfix) with ESMTP id 45AEF1009D30E; Mon, 27 Apr 2020 05:27:56 -0700 (PDT) Received-SPF: None (mailfrom) identity=mailfrom; client-ip=2607:7c80:54:e::133; helo=bombadil.infradead.org; envelope-from=willy@infradead.org; receiver= Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:e::133]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id 85AE81009D30A for ; Mon, 27 Apr 2020 05:27:51 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=Wzixkdd1MP05tKyiJudvvJUbNJ4oUXlhwu6lo0T90lk=; b=h4uZN/H6Mu3d0zPdDsclCVH32p 44gY3nD6XgbLkqBBMl44AzSP/BJE3KBzRAPQwmBogEvavTEhIQUL3ocaF+cw7UkzuVAwITD4seBgk Pp8Hl1+tIQ8RODfstqU0/krSNx7E830cBVrxSyf5dfg0gpQoKrJKe2M5AynwMKOl0n3mi6Pl4oFKf efaEddM5vpsfG757hkc2v8IEonhVlf8jAZ4wp/U05w15FPDDSa7fkY0VDdkD1WHqV691GKsmZEkS8 SOQI03I+FKN/fUWcflc8dcvjdXytbEbhLDXDLTXiJZruWD/RddNBs2RHT5uDy951iViKV1ctgL7yg iJXmOD4A==; Received: from willy by bombadil.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1jT2sG-0003WE-Dr; Mon, 27 Apr 2020 12:28:36 +0000 Date: Mon, 27 Apr 2020 05:28:36 -0700 From: Matthew Wilcox To: Shiyang Ruan Subject: Re: [RFC PATCH 0/8] dax: Add a dax-rmap tree to support reflink Message-ID: <20200427122836.GD29705@bombadil.infradead.org> References: <20200427084750.136031-1-ruansy.fnst@cn.fujitsu.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20200427084750.136031-1-ruansy.fnst@cn.fujitsu.com> Message-ID-Hash: 4F5VIDHBLEDHUYPDQQBNKS44WUZENACB X-Message-ID-Hash: 4F5VIDHBLEDHUYPDQQBNKS44WUZENACB X-MailFrom: willy@infradead.org X-Mailman-Rule-Hits: nonmember-moderation X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation CC: linux-kernel@vger.kernel.org, linux-xfs@vger.kernel.org, linux-nvdimm@lists.01.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, darrick.wong@oracle.com, david@fromorbit.com, hch@lst.de, rgoldwyn@suse.de, qi.fuli@fujitsu.com, y-goto@fujitsu.com X-Mailman-Version: 3.1.1 Precedence: list List-Id: "Linux-nvdimm developer list." Archived-At: List-Archive: List-Help: List-Post: List-Subscribe: List-Unsubscribe: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit On Mon, Apr 27, 2020 at 04:47:42PM +0800, Shiyang Ruan wrote: > This patchset is a try to resolve the shared 'page cache' problem for > fsdax. > > In order to track multiple mappings and indexes on one page, I > introduced a dax-rmap rb-tree to manage the relationship. A dax entry > will be associated more than once if is shared. At the second time we > associate this entry, we create this rb-tree and store its root in > page->private(not used in fsdax). Insert (->mapping, ->index) when > dax_associate_entry() and delete it when dax_disassociate_entry(). Do we really want to track all of this on a per-page basis? I would have thought a per-extent basis was more useful. Essentially, create a new address_space for each shared extent. Per page just seems like a huge overhead. _______________________________________________ Linux-nvdimm mailing list -- linux-nvdimm@lists.01.org To unsubscribe send an email to linux-nvdimm-leave@lists.01.org