From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753536AbbGOLRS (ORCPT ); Wed, 15 Jul 2015 07:17:18 -0400 Received: from mail-pa0-f51.google.com ([209.85.220.51]:33842 "EHLO mail-pa0-f51.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752134AbbGOLRR (ORCPT ); Wed, 15 Jul 2015 07:17:17 -0400 Date: Wed, 15 Jul 2015 20:16:25 +0900 From: Sergey Senozhatsky To: Minchan Kim Cc: Sergey Senozhatsky , Sergey Senozhatsky , Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 0/3] zsmalloc: small compaction improvements Message-ID: <20150715111625.GC3998@swordfish> References: <1436607932-7116-1-git-send-email-sergey.senozhatsky@gmail.com> <20150713233602.GA31822@blaptop.AC68U> <20150714003132.GA2463@swordfish> <20150714005459.GA12786@blaptop.AC68U> <20150714122932.GA597@swordfish> <20150714165224.GA384@blaptop> <20150715002106.GA742@swordfish> <20150715002359.GA29240@blaptop.AC68U> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150715002359.GA29240@blaptop.AC68U> User-Agent: Mutt/1.5.23+102 (2ca89bed6448) (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On (07/15/15 09:24), Minchan Kim wrote: > On Wed, Jul 15, 2015 at 09:21:06AM +0900, Sergey Senozhatsky wrote: > > On (07/15/15 01:52), Minchan Kim wrote: > > > > alrighty... again... > > > > > > > > > > > > > > > > /sys/block/zram/compact is a black box. We provide it, we don't > > > > > > throttle it in the kernel, and user space is absolutely clueless when > > > > > > it invokes compaction. From some remote (or alternative) point of > > > > > > > > > > But we have zs_can_compact so it can effectively skip the class if it > > > > > is not proper class. > > > > > > > > user triggered compaction can compact too much. > > > > in its current state triggering a compaction from user space is like > > > > playing a lottery or a russian roulette. > > > > > > We were on different page. > > > > > I thought the motivation from this patchset is to prevent compaction > > > overhead by frequent user-driven compaction request because user > > > don't know how they can get free pages by compaction so they should > > > ask compact frequently with blind. > > > > this is exactly the motivation for this patchset. seriously. > > User should rely on the auto-compaction. yep, which will be available in 5-6 months... right behind the corner. -ss