From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933791AbcCNHoL (ORCPT ); Mon, 14 Mar 2016 03:44:11 -0400 Received: from mail-pf0-f193.google.com ([209.85.192.193]:35265 "EHLO mail-pf0-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933649AbcCNHoG (ORCPT ); Mon, 14 Mar 2016 03:44:06 -0400 Date: Mon, 14 Mar 2016 16:45:23 +0900 From: Sergey Senozhatsky To: Minchan Kim Cc: Sergey Senozhatsky , Andrew Morton , Joonsoo Kim , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Sergey Senozhatsky Subject: Re: [RFC][PATCH v3 2/5] mm/zsmalloc: remove shrinker compaction callbacks Message-ID: <20160314074523.GB542@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> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160314063207.GD10675@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 (03/14/16 15:32), Minchan Kim wrote: > On Thu, Mar 03, 2016 at 11:46:00PM +0900, Sergey Senozhatsky wrote: > > Do not register shrinker compaction callbacks anymore, since > > now we shedule class compaction work each time its fragmentation > > value goes above the watermark. > > 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 b) a compaction from zs_free() that can bail out c) a compaction triggered by the shrinker. all 3 three can run simultaneously. _if_ we can keep every class below its watermark, we can reduce the need of "c)". -ss