From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754601AbcCOBEY (ORCPT ); Mon, 14 Mar 2016 21:04:24 -0400 Received: from mail-pf0-f170.google.com ([209.85.192.170]:33086 "EHLO mail-pf0-f170.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754477AbcCOBEV (ORCPT ); Mon, 14 Mar 2016 21:04:21 -0400 Date: Tue, 15 Mar 2016 10:05:42 +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 v3 2/5] mm/zsmalloc: remove shrinker compaction callbacks Message-ID: <20160315010542.GB2126@swordfish> References: <1457016363-11339-1-git-send-email-sergey.senozhatsky@gmail.com> <1457016363-11339-3-git-send-email-sergey.senozhatsky@gmail.com> <20160314063207.GD10675@bbox> <20160314074523.GB542@swordfish> <20160315005249.GB19514@bbox> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160315005249.GB19514@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 (03/15/16 09:52), Minchan Kim wrote: [..] > > > I suggested to remove shrinker compaction but while I review your > > > first patch in this thread, I thought we need upper-bound to > > > compact zspage so background work can bail out for latency easily. > > > IOW, the work could give up the job. In such case, we might need > > > fall-back scheme to continue the job. And I think that could be > > > a shrinker. > > > > > > What do you think? > > > > wouldn't this unnecessarily complicate the whole thing? we would > > have > > a) a compaction that can be triggered by used space > > Maybe, user space? :) haha, yes! sorry, I do quite a lot of typos. > > b) a compaction from zs_free() that can bail out > > c) a compaction triggered by the shrinker. > > > > all 3 three can run simultaneously. > > Yeb. > > > > > > > _if_ we can keep every class below its watermark, we can reduce the > > need of "c)". > > But the problem is timing. We cannot guarantee when background > compaction triggers while shrinker is interop with VM so we should > do the job instantly for the system. we can have pool's compaction-kthread that we will wake_up() every time we need a compaction, with no dependency on workqueue or shrinker. -ss