From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S945969AbdDTNdr (ORCPT ); Thu, 20 Apr 2017 09:33:47 -0400 Received: from bombadil.infradead.org ([65.50.211.133]:37070 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S945316AbdDTNdo (ORCPT ); Thu, 20 Apr 2017 09:33:44 -0400 Date: Thu, 20 Apr 2017 06:33:38 -0700 From: Matthew Wilcox To: Laurent Dufour Cc: linux-mm@kvack.org, Davidlohr Bueso , akpm@linux-foundation.org, Jan Kara , "Kirill A . Shutemov" , Michal Hocko , Peter Zijlstra , Mel Gorman , haren@linux.vnet.ibm.com, aneesh.kumar@linux.vnet.ibm.com, khandual@linux.vnet.ibm.com, Paul.McKenney@us.ibm.com, linux-kernel@vger.kernel.org Subject: Re: [RFC 0/4] Replace mmap_sem by a range lock Message-ID: <20170420133338.GC27790@bombadil.infradead.org> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.8.0 (2017-02-23) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Apr 19, 2017 at 02:18:23PM +0200, Laurent Dufour wrote: > Following the series pushed by Davidlohr Bueso based on the Jan Kara's > work [1] which introduces range locks, this series implements the > first step of the attempt to replace the mmap_sem by a range lock. Have you previously documented attempts to replace the mmap_sem by an existing lock type before introducing a new (and frankly weird) lock? My initial question is "Why not use RCU for this?" -- the rxrpc code uses an rbtree protected by RCU.