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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 592F1C433F5 for ; Wed, 27 Apr 2022 18:13:12 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 8910B6B0071; Wed, 27 Apr 2022 14:13:11 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 8419B6B0073; Wed, 27 Apr 2022 14:13:11 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 70A956B0074; Wed, 27 Apr 2022 14:13:11 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (relay.hostedemail.com [64.99.140.26]) by kanga.kvack.org (Postfix) with ESMTP id 5F6576B0071 for ; Wed, 27 Apr 2022 14:13:11 -0400 (EDT) Received: from smtpin17.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay09.hostedemail.com (Postfix) with ESMTP id 0F84428EFB for ; Wed, 27 Apr 2022 18:13:11 +0000 (UTC) X-FDA: 79403455782.17.B6238F0 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) by imf23.hostedemail.com (Postfix) with ESMTP id D712A140045 for ; Wed, 27 Apr 2022 18:13:03 +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=S3JuW/SM98WH2rFrFeqGk8MdEjJ3XU4x3GX4vPeS2bI=; b=WWryCU6reEJAjmZsxdPsnMqlqJ pIzLPwOF97Vd080BBhRV7WaV8DJyeeMNpaSJ68OPAM35wOsmPa8F4Y/EBBygrF71JRn8wqptTPM/N 3F+HgB51lidwodYeX2YHiNoWArzFEtZVmnzA30rQ5ASahwmBHxmEorL6Dv8EqszgBKbaAutohBOum aBBdRoqGmymEK7lD0SEqcXUz/842aLs2uJedrbXvAXdYe7jfonV7n1qx0vtxe/CWzRxvwLFCw0p+1 VclzLATezRkvhof54tplPeojouC8Zf2R5ezsd66nK4EuU/48LKZk/9tVMx3AgE6SVIg4rAQs/O2UM c+V6GrTA==; Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1njm9q-00AmQj-7t; Wed, 27 Apr 2022 18:12:58 +0000 Date: Wed, 27 Apr 2022 19:12:58 +0100 From: Matthew Wilcox To: Andrew Morton Cc: Liam Howlett , "maple-tree@lists.infradead.org" , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , Yu Zhao , Davidlohr Bueso Subject: Re: [PATCH v8 00/70] Introducing the Maple Tree Message-ID: References: <20220426150616.3937571-1-Liam.Howlett@oracle.com> <20220426130857.09f40743b42b5f0bf4f19a59@linux-foundation.org> <20220427140832.mpvnnkkhrbupk46i@revolver> <20220427103331.9876ad87626af0f50e9ced0d@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220427103331.9876ad87626af0f50e9ced0d@linux-foundation.org> X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: D712A140045 X-Stat-Signature: q65detgk8wpyjtot34w9u9au8583mgu9 Authentication-Results: imf23.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=WWryCU6r; dmarc=none; spf=none (imf23.hostedemail.com: domain of willy@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=willy@infradead.org X-Rspam-User: X-HE-Tag: 1651083183-227120 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, Apr 27, 2022 at 10:33:31AM -0700, Andrew Morton wrote: > On Wed, 27 Apr 2022 14:08:39 +0000 Liam Howlett wrote: > > The benchmarks are around the same as they have always been. > > So it's presently a wash. > > That makes "the plan" (below) really critical, otherwise there seems > little point in merging this code at this time? > > Please send me many very soothing words about how confident we should > be that the plan will be implemented and that it shall be good? Yes, performance-wise it's a wash. However, Davidlohr was very impressed that it was a wash because we're actually getting rid of three data structures here; the linked list, the rbtree and the vmacache. His opinion was that we should push the maple tree in now, in advance of the future RCU uses. We also have other users waiting in the wings. Dave Howells has something he's working on that uses the maple tree directly. I have a couple of XArray users that are using it inappropriately that I want to convert ... I just didn't want to do that work before all this lands. The current LSFMM schedule has very many words about the Maple tree scheduled for 13:30-15:00 on Monday. Hopefully we'll have a better idea after that how confident we are that RCU VMA walking is going to work.