From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wj0-f200.google.com (mail-wj0-f200.google.com [209.85.210.200]) by kanga.kvack.org (Postfix) with ESMTP id 912406B0038 for ; Wed, 18 Jan 2017 16:18:50 -0500 (EST) Received: by mail-wj0-f200.google.com with SMTP id c7so4763220wjb.7 for ; Wed, 18 Jan 2017 13:18:50 -0800 (PST) Received: from mx2.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id y1si1715892wrc.161.2017.01.18.13.18.49 for (version=TLS1 cipher=AES128-SHA bits=128/128); Wed, 18 Jan 2017 13:18:49 -0800 (PST) Date: Wed, 18 Jan 2017 22:18:42 +0100 From: Michal Hocko Subject: Re: + mm-swap-add-cluster-lock-v5.patch added to -mm tree Message-ID: <20170118211842.GE17135@dhcp22.suse.cz> References: <587eaca3.MRSwND8OEi+lF+VH%akpm@linux-foundation.org> <20170118083731.GF7015@dhcp22.suse.cz> <20170118122354.9b06459e2588e53b537ca78c@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170118122354.9b06459e2588e53b537ca78c@linux-foundation.org> Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: ying.huang@intel.com, aarcange@redhat.com, aaron.lu@intel.com, ak@linux.intel.com, borntraeger@de.ibm.com, corbet@lwn.net, dave.hansen@intel.com, hannes@cmpxchg.org, hillf.zj@alibaba-inc.com, hughd@google.com, kirill.shutemov@linux.intel.com, minchan@kernel.org, riel@redhat.com, shli@kernel.org, tim.c.chen@linux.intel.com, vdavydov.dev@gmail.com, mm-commits@vger.kernel.org, linux-mm@kvack.org On Wed 18-01-17 12:23:54, Andrew Morton wrote: > On Wed, 18 Jan 2017 09:37:31 +0100 Michal Hocko wrote: > > > On Tue 17-01-17 15:45:39, Andrew Morton wrote: > > [...] > > > From: "Huang\, Ying" > > > Subject: mm-swap-add-cluster-lock-v5 > > > > I assume you are going to fold this into the original patch. Do you > > think it would make sense to have it in a separate patch along with > > the reasoning provided via email? > > It should be OK - the v5 changelog (which I shall use for the folded > patch, as usual) has > > : Compared with a previous implementation using bit_spin_lock, the > : sequential swap out throughput improved about 3.2%. Test was done on a > : Xeon E5 v3 system. The swap device used is a RAM simulated PMEM > : (persistent memory) device. To test the sequential swapping out, the test > : case created 32 processes, which sequentially allocate and write to the > : anonymous pages until the RAM and part of the swap device is used. But there are more reasons than the throughput improvements. I would consider the full lockdep support and fairness more important. The drawback is the memory footprint which should be mentioned as well. That being said, I will not insist, I just thought that this would be a nice incremental change and easier to understand later rather than searching the archives... So take all this as my 2c... -- Michal Hocko SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org