From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755599AbbIYIr2 (ORCPT ); Fri, 25 Sep 2015 04:47:28 -0400 Received: from mail-pa0-f52.google.com ([209.85.220.52]:36728 "EHLO mail-pa0-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755442AbbIYIrY (ORCPT ); Fri, 25 Sep 2015 04:47:24 -0400 Date: Fri, 25 Sep 2015 17:47:13 +0900 From: Minchan Kim To: Vitaly Wool Cc: Seth Jennings , Dan Streetman , Andrew Morton , Sergey Senozhatsky , linux-kernel , Linux-MM Subject: Re: [PATCH v2] zbud: allow up to PAGE_SIZE allocations Message-ID: <20150925084617.GA23340@blaptop> References: <20150922141733.d7d97f59f207d0655c3b881d@gmail.com> <20150923031845.GA31207@cerebellum.local.variantweb.net> <20150923215726.GA17171@cerebellum.local.variantweb.net> <20150925021325.GA16431@bbox> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Sep 25, 2015 at 10:17:54AM +0200, Vitaly Wool wrote: > > > I already said questions, opinion and concerns but anything is not clear > > until now. Only clear thing I could hear is just "compaction stats are > > better" which is not enough for me. Sorry. > > > > 1) https://lkml.org/lkml/2015/9/15/33 > > 2) https://lkml.org/lkml/2015/9/21/2 > > Could you please stop perverting the facts, I did answer to that: > https://lkml.org/lkml/2015/9/21/753. > > Apart from that, an opinion is not necessarily something I would > answer. Concerns about zsmalloc are not in the scope of this patch's > discussion. If you have any concerns regarding this particular patch, > please let us know. Yes, I don't want to interrupt zbud thing which is Seth should maintain and I respect his decision but the reason I nacked is you said this patch aims for supporing zbud into zsmalloc for determinism. For that, at least, you should discuss with me and Sergey but I feel you are ignoring our comments. > > > Vitally, Please say what's the root cause of your problem and if it > > is external fragmentation, what's the problem of my approach? > > > > 1) make non-LRU page migrate > > 2) provide zsmalloc's migratpage > > The problem with your approach is that in your world I need to prove > my right to use zbud. This is a very strange speculation. No. If you want to contribute something, you should prove why yours is better. I already said my concerns and my approach. It's your turn that you should explain why it's better. > > > We should provide it for CMA as well as external fragmentation. > > I think we could solve your issue with above approach and > > it fundamentally makes zsmalloc/zbud happy in future. > > I doubt that but I'll answer in this thread: > https://lkml.org/lkml/2015/9/15/33 as zsmalloc deficiencies do not > have direct relation to this particular patch. > > > Also, please keep it in mind that zram has been in linux kernel for > > memory efficiency for a long time and later zswap/zbud was born > > for *determinism* at the cost of memory efficiency. > > Yep, and determinism is more important to me than the memory > efficiency. Dropping the compression ration from 3.2x to 1.8x is okay > with me and stalls in UI are not. Then, you could use zswap which have aimed for it with small changes to prevent writeback. > > ~vitaly -- Kind regards, Minchan Kim