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=-3.5 required=3.0 tests=BAYES_00,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 9D4ECC43461 for ; Wed, 16 Sep 2020 11:47:03 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 2E2E522209 for ; Wed, 16 Sep 2020 11:47:01 +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="c6d1Pe73" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2E2E522209 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 7A0276B0003; Wed, 16 Sep 2020 07:47:00 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 74F1D6B0037; Wed, 16 Sep 2020 07:47:00 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 5F1226B0055; Wed, 16 Sep 2020 07:47:00 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0198.hostedemail.com [216.40.44.198]) by kanga.kvack.org (Postfix) with ESMTP id 487B76B0003 for ; Wed, 16 Sep 2020 07:47:00 -0400 (EDT) Received: from smtpin11.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 04CD5181AEF1A for ; Wed, 16 Sep 2020 11:47:00 +0000 (UTC) X-FDA: 77268748200.11.flock16_280aa8f27119 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin11.hostedemail.com (Postfix) with ESMTP id CD074180F8B81 for ; Wed, 16 Sep 2020 11:46:59 +0000 (UTC) X-HE-Tag: flock16_280aa8f27119 X-Filterd-Recvd-Size: 3088 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) by imf34.hostedemail.com (Postfix) with ESMTP for ; Wed, 16 Sep 2020 11:46:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.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=hjBH8eVL+KDdz8o5+TTH4XgmzDXF3Ypdoh1lK++brXA=; b=c6d1Pe73asPhsa8UwmMbFCMHuc 30c0hUpFGmdZ3T+2maRv/Aphr+ijWpB6twr3lqPXo3SqRcE3m1fLfQHupLkwInCNBhg4EbNliywyp 5tn7MJ6HuZr1OyIOc1gZ6+tuezc1NNz6SnMqtbCc1g4R8I4h6PCPeLsLGwopt927alBBTvq2fJCBx yr9h4lzYKBVGV0lx5e8QpHoBDPBURlS8Y64isfcdaej5vhJdW+46SDYfJNHdv1OFxRBW4V7kIE0iP xNp2P2Bl0MwFONf+QJ3w3fKDjvhk+faEKwV+Qqwd/jYxU7uu6VwJmWjdk2v3nCspmSLdN4ZSQcQFv rc2+HYxw==; Received: from willy by casper.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1kIVth-0002Mx-Lo; Wed, 16 Sep 2020 11:46:49 +0000 Date: Wed, 16 Sep 2020 12:46:49 +0100 From: Matthew Wilcox To: Christoph Hellwig Cc: Alexander Viro , linux-fsdevel@vger.kernel.org, Hugh Dickins , Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Song Liu , Rik van Riel , "Kirill A . Shutemov" , Johannes Weiner , Dave Chinner Subject: Re: [PATCH 2/2] fs: Do not update nr_thps for mappings which support THPs Message-ID: <20200916114649.GM5449@casper.infradead.org> References: <20200916032717.22917-1-willy@infradead.org> <20200916032717.22917-2-willy@infradead.org> <20200916052126.GA12923@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200916052126.GA12923@infradead.org> X-Rspamd-Queue-Id: CD074180F8B81 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam05 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Wed, Sep 16, 2020 at 06:21:26AM +0100, Christoph Hellwig wrote: > On Wed, Sep 16, 2020 at 04:27:17AM +0100, Matthew Wilcox (Oracle) wrote: > > The nr_thps counter is to support THPs in the page cache when the > > filesystem doesn't understand THPs. Eventually it will be removed, but > > we should still support filesystems which do not understand THPs yet. > > Move the nr_thp manipulation functions to filemap.h since they're > > page-cache specific. > > Honestly I don't think we should support the read-only THP crap. We > should in fact never have merged that bandaid to start with given that > you did good progress on the real thing. I'd like to see the feature ripped out again, yes. Once we have a few more filesystems converted, I think that'll be a reasonable thing to do. It was a good step along the way; Song fixed a number of problems, and worked on other things that I never had to learn anything about (like uprobes and khugepaged). I wouldn't go so far as to say we should never have merged it, but I think we can remove it in about six months.