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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B02D1C433EF for ; Wed, 27 Apr 2022 18:13:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233820AbiD0SQZ (ORCPT ); Wed, 27 Apr 2022 14:16:25 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57012 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229598AbiD0SQW (ORCPT ); Wed, 27 Apr 2022 14:16:22 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 89C5638BB for ; Wed, 27 Apr 2022 11:13:09 -0700 (PDT) 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> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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.