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=-2.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 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 19C1DC3A5A5 for ; Tue, 3 Sep 2019 06:58:13 +0000 (UTC) Received: from whitealder.osuosl.org (smtp1.osuosl.org [140.211.166.138]) (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 E01C5206B8 for ; Tue, 3 Sep 2019 06:58:12 +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="rpXp0SPn" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E01C5206B8 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=driverdev-devel-bounces@linuxdriverproject.org Received: from localhost (localhost [127.0.0.1]) by whitealder.osuosl.org (Postfix) with ESMTP id 7899A875D7; Tue, 3 Sep 2019 06:58:12 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from whitealder.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id zHUA5netRwzh; Tue, 3 Sep 2019 06:58:10 +0000 (UTC) Received: from ash.osuosl.org (ash.osuosl.org [140.211.166.34]) by whitealder.osuosl.org (Postfix) with ESMTP id BE508875BA; Tue, 3 Sep 2019 06:58:10 +0000 (UTC) Received: from whitealder.osuosl.org (smtp1.osuosl.org [140.211.166.138]) by ash.osuosl.org (Postfix) with ESMTP id 01FC41BF25F for ; Tue, 3 Sep 2019 06:58:10 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by whitealder.osuosl.org (Postfix) with ESMTP id EF317875BA for ; Tue, 3 Sep 2019 06:58:09 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from whitealder.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id UF0uiK7RS2BR for ; Tue, 3 Sep 2019 06:58:09 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) by whitealder.osuosl.org (Postfix) with ESMTPS id 71ECC875B9 for ; Tue, 3 Sep 2019 06:58:09 +0000 (UTC) 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:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=4hSYkiCPCpSgRGHZSvIjoW5chKDDuf7TDPZ/KesWimM=; b=rpXp0SPnAU2Bqz1hm0nm2/Yhf UNxaHXOTptV/vZxgW3l45UkXmbSzFCF6jpcGgR4N3NWzh00kL4gHglfJtSMHQvR60R6+PNJDDrW0d nlQ6UmPC6dG+rbeDzAOVh+DAfSlcO467RK/ptDPHANCLGc0TquzUn/UuPyqUQQAs9e/x7qVnC0pN5 oGhHbdcJW7UypcG0tDscA3Rv00tKuFzAz15Ot23KmxGbbcv4gjTz0zF3F72iLahRGtWWNR3c8raTD m0dAbbkkgkLz1z+7Yy5HZ8Y5BF/zMkUDMO5uyeI7JxTtiMS8hPeSYqePPLoHLc+WsBf4OrHTAsIfJ W14CT7M+A==; Received: from hch by bombadil.infradead.org with local (Exim 4.92 #3 (Red Hat Linux)) id 1i52lP-0003At-I5; Tue, 03 Sep 2019 06:58:03 +0000 Date: Mon, 2 Sep 2019 23:58:03 -0700 From: Christoph Hellwig To: Gao Xiang Subject: Re: [PATCH 00/21] erofs: patchset addressing Christoph's comments Message-ID: <20190903065803.GA11205@infradead.org> References: <20190802125347.166018-1-gaoxiang25@huawei.com> <20190901055130.30572-1-hsiangkao@aol.com> <20190902124645.GA8369@infradead.org> <20190902142452.GE2664@architecture4> <20190902152323.GB14009@infradead.org> <20190902155037.GD179615@architecture4> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20190902155037.GD179615@architecture4> User-Agent: Mutt/1.11.4 (2019-03-13) X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html X-BeenThere: driverdev-devel@linuxdriverproject.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux Driver Project Developer List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: devel@driverdev.osuosl.org, Chao Yu , Greg Kroah-Hartman , Christoph Hellwig , linux-fsdevel@vger.kernel.org, linux-erofs@lists.ozlabs.org, Chao Yu Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: driverdev-devel-bounces@linuxdriverproject.org Sender: "devel" On Mon, Sep 02, 2019 at 11:50:38PM +0800, Gao Xiang wrote: > > > You means killing erofs_get_meta_page or avoid erofs_read_raw_page? > > > > > > - For killing erofs_get_meta_page, here is the current erofs_get_meta_page: > > > > > I think it is simple enough. read_cache_page need write a similar > > > filler, or read_cache_page_gfp will call .readpage, and then > > > introduce buffer_heads, that is what I'd like to avoid now (no need these > > > bd_inode buffer_heads in memory...) > > > > If using read_cache_page_gfp and ->readpage works, please do. The > > fact that the block device inode uses buffer heads is an implementation > > detail that might not last very long and should be invisible to you. > > It also means you can get rid of a lot of code that you don't have > > to maintain and others don't have to update for global API changes. > > I care about those useless buffer_heads in memory for our products... > > Since we are nobh filesystem (a little request, could I use it > after buffer_heads are fully avoided, I have no idea why I need > those buffer_heads in memory.... But I think bd_inode is good > for caching metadata...) Then please use read_cache_page with iomap_readpage(s), and write comment explaining why your are not using read_cache_page_gfp. _______________________________________________ devel mailing list devel@linuxdriverproject.org http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel