From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964806AbcIPNZz (ORCPT ); Fri, 16 Sep 2016 09:25:55 -0400 Received: from merlin.infradead.org ([205.233.59.134]:54918 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933530AbcIPNZO (ORCPT ); Fri, 16 Sep 2016 09:25:14 -0400 Date: Fri, 16 Sep 2016 15:25:06 +0200 From: Peter Zijlstra To: Mel Gorman Cc: LKML , Linux-MM , Dave Chinner , Linus Torvalds , Ying Huang , Michal Hocko Subject: Re: [PATCH 1/4] mm, vmscan: Batch removal of mappings under a single lock during reclaim Message-ID: <20160916132506.GB5035@twins.programming.kicks-ass.net> References: <1473415175-20807-1-git-send-email-mgorman@techsingularity.net> <1473415175-20807-2-git-send-email-mgorman@techsingularity.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1473415175-20807-2-git-send-email-mgorman@techsingularity.net> User-Agent: Mutt/1.5.23.1 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Sep 09, 2016 at 10:59:32AM +0100, Mel Gorman wrote: > Pages unmapped during reclaim acquire/release the mapping->tree_lock for > every single page. There are two cases when it's likely that pages at the > tail of the LRU share the same mapping -- large amounts of IO to/from a > single file and swapping. This patch acquires the mapping->tree_lock for > multiple page removals. So, once upon a time, in a galaxy far away,.. I did a concurrent pagecache patch set that replaced the tree_lock with a per page bit- spinlock and fine grained locking in the radix tree. I know the mm has changed quite a bit since, but would such an approach still be feasible? I cannot seem to find an online reference to a 'complete' version of that patch set, but I did find the OLS paper on it and I did find some copies on my local machines.