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 AB1ACC2D0DB for ; Thu, 30 Jan 2020 13:39:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 75FB52082E for ; Thu, 30 Jan 2020 13:39:26 +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="Tnfgt7+8" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727311AbgA3NjZ (ORCPT ); Thu, 30 Jan 2020 08:39:25 -0500 Received: from bombadil.infradead.org ([198.137.202.133]:35216 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726902AbgA3NjZ (ORCPT ); Thu, 30 Jan 2020 08:39:25 -0500 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:To:From:Date:Sender:Reply-To:Cc: 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=BaJshAr22CaKcM0UOV3hgnNZiVpLcu9aI8ljbX4iyc0=; b=Tnfgt7+8wRJD1nPf4+Qufbalw vO6IglycUd42qnKx/KgYZsqHyEtqiUucJjuyWdEyPjX92X6rNEBMfZ0ePAHxE3ABvq6BXyGrW5tgL WCmtgD2UenO2yEGydau2oueOtTz0i+GTVBBERMv0AZ0d6PKSMboVWQyv/CNE7ufD9l3wwhNcAgG+Y +QueUrWMkCGySJnLW3qo3XQjh+ibYHYpudUwhGZudy3oU9lfPzI+Nyzv5AX8VAqDqVpi2xcrpYjJV We/IH0G/SRRpuQKbtMc8Wbl6TTn1mr1iVyzqkovfrEE1cKAjkTxjIo+TXflVbr6CYvdCs4J4dSCQb FIL5Hn3QA==; Received: from hch by bombadil.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1ixA2T-0006Kh-Gt; Thu, 30 Jan 2020 13:39:21 +0000 Date: Thu, 30 Jan 2020 05:39:21 -0800 From: Christoph Hellwig To: dsterba@suse.cz, Johannes Thumshirn , David Sterba , Nikolay Borisov , "linux-btrfs @ vger . kernel . org" Subject: Re: [PATCH v3 0/5] btrfs: remove buffer heads form superblock handling Message-ID: <20200130133921.GA21841@infradead.org> References: <20200127155931.10818-1-johannes.thumshirn@wdc.com> <20200129142526.GE3929@twin.jikos.cz> <20200130121530.GO3929@twin.jikos.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200130121530.GO3929@twin.jikos.cz> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org On Thu, Jan 30, 2020 at 01:15:30PM +0100, David Sterba wrote: > > Sure but with hch's proposed change to using read_cache_page_gfp() this > > doesn't make too much sense anymore at least for the read path. > > > > Maybe "use page cache for superblock reading"? > > That works too. We might need a new iteration that summarizes up all the > feedback so far, so we have same code to refer to. Per my question on the second patch: why even use the page cache at all. btrfs already caches the value outside the pagecache, so why even bother with the page cache overhead?