From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752820AbcBVB75 (ORCPT ); Sun, 21 Feb 2016 20:59:57 -0500 Received: from mail-pf0-f181.google.com ([209.85.192.181]:36456 "EHLO mail-pf0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752558AbcBVB74 (ORCPT ); Sun, 21 Feb 2016 20:59:56 -0500 Date: Mon, 22 Feb 2016 11:01:13 +0900 From: Sergey Senozhatsky To: Minchan Kim Cc: Sergey Senozhatsky , Sergey Senozhatsky , Andrew Morton , Joonsoo Kim , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [RFC][PATCH v2 3/3] mm/zsmalloc: increase ZS_MAX_PAGES_PER_ZSPAGE Message-ID: <20160222020113.GB488@swordfish> References: <1456061274-20059-1-git-send-email-sergey.senozhatsky@gmail.com> <1456061274-20059-4-git-send-email-sergey.senozhatsky@gmail.com> <20160222002515.GB21710@bbox> <20160222004758.GB4958@swordfish> <20160222013442.GB27829@bbox> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160222013442.GB27829@bbox> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On (02/22/16 10:34), Minchan Kim wrote: [..] > > > I tempted it several times with same reason you pointed out. > > > But my worry was that if we increase ZS_MAX_ZSPAGE_ORDER, zram can > > > consume more memory because we need several pages chain to populate > > > just a object. Even, at that time, we didn't have compaction scheme > > > so fragmentation of object in zspage is huge pain to waste memory. > > > > well, the thing is -- we end up requesting less pages after all, so > > zsmalloc has better chances to survive. for example, gcc5 compilation test > > Indeed. I saw your test result. [..] > > Total 129 489 1627756 1618193 850147 > > > > > > that's 891703 - 850147 = 41556 less pages. or 162MB less memory used. > > 41556 less pages means that zsmalloc had 41556 less chances to fail. > > > Let's think swap-case which is more important for zram now. As you know, > most of usecase are swap in embedded world. > Do we really need 16 pages allocator for just less PAGE_SIZE objet > at the moment which is really heavy memory pressure? I'll take a look at dynamic class page addition. -ss