From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: util-linux-owner@vger.kernel.org Received: from mx1.redhat.com ([209.132.183.28]:23415 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753446AbaHFIU3 (ORCPT ); Wed, 6 Aug 2014 04:20:29 -0400 Date: Wed, 6 Aug 2014 10:20:26 +0200 From: Karel Zak To: kerolasa@gmail.com Cc: util-linux , Sergey Senozhatsky Subject: Re: [PATCH 8/8] zramctl: allow use of --algorithm and --streams alone Message-ID: <20140806082026.GH19820@x2.net.home> References: <1407107290-5806-1-git-send-email-kerolasa@iki.fi> <20140804115556.GA6923@x2.net.home> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: Sender: util-linux-owner@vger.kernel.org List-ID: On Tue, Aug 05, 2014 at 11:36:59PM +0100, Sami Kerola wrote: > On 4 August 2014 12:55, Karel Zak wrote: > > On Mon, Aug 04, 2014 at 12:08:10AM +0100, Sami Kerola wrote: > >> Earlier the --algorithm and --streams had to be combined with --size. To > >> user requirement to combine with --size was indirectly told using > >> following message. > > > > And is it really supported by kernel? I see in > > Documentation/blockdev/zram.txt: > > > > In order to enable compression backend's multi stream support > > max_comp_streams must be initially set to desired concurrency > > level before ZRAM device initialisation. > > > > I guess that when you set disksize the zram device is "locked" for > > setting changes. It means that modify already initialized (created) > > zram devices is impossible. You have to reset the device to "unlock" > > the device setting. > > After playing with zramctl I found out --algorithm must be set before > --size. The --streams can be set after --size, but not if device is in use. > When device is in use none of the settings are allowed. I'd like to keep the command line semantic simple and stupid and support --streams and --algorithm for device initialization (it means with --size) only. We don't have to export to command line all the crazy kernel implementation details. Karel -- Karel Zak http://karelzak.blogspot.com