Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753392Ab0KKJcC (ORCPT ); Thu, 11 Nov 2010 04:32:02 -0500 Received: from cantor.suse.de ([195.135.220.2]:58846 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751997Ab0KKJb6 (ORCPT ); Thu, 11 Nov 2010 04:31:58 -0500 Date: Thu, 11 Nov 2010 10:31:55 +0100 From: Michal Hocko To: Daisuke Nishimura Cc: linux-mm@kvack.org, KAMEZAWA Hiroyuki , linux-kernel@vger.kernel.org Subject: Re: [RFC PATCH] Make swap accounting default behavior configurable Message-ID: <20101111093155.GA20630@tiehlicka.suse.cz> References: <20101110125154.GC5867@tiehlicka.suse.cz> <20101111094613.eab2ec0b.nishimura@mxp.nes.nec.co.jp> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20101111094613.eab2ec0b.nishimura@mxp.nes.nec.co.jp> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6937 Lines: 178 On Thu 11-11-10 09:46:13, Daisuke Nishimura wrote: > On Wed, 10 Nov 2010 13:51:54 +0100 > Michal Hocko wrote: > > > Hi, > > could you consider the patch bellow? It basically changes the default > > swap accounting behavior (when it is turned on in configuration) to be > > configurable as well. > > > > The rationale is described in the patch but in short it makes it much > > more easier to enable this feature in distribution kernels as the > > functionality can be provided in the general purpose kernel (with the > > option disabled) without any drawbacks and interested users can enable > > it. This is not possible currently. > > > > I am aware that boot command line parameter name change is not ideal but > > the original semantic wasn't good enough and I don't like > > noswapaccount=yes|no very much. > > > > If we really have to stick to it I can rework the patch to keep the name > > and just add the yes|no logic, though. Or we can keep the original one > > and add swapaccount paramete which would mean the oposite as the other > > one. > > > hmm, I agree that current parameter name(noswapaccount) is not desirable > for yes|no, but IMHO changing the user interface(iow, making what worked before > unusable) is worse. > > Although I'm not sure how many people are using this parameter, I vote for > using "noswapaccount[=(yes|no)]". Isn't a new swapaccount parameter better than that? I know we don't want to have too many parameters but having a something with a clear meaning is better IMO (noswapaccount=no doesn't sound very intuitive to me). > And you should update Documentation/kernel-parameters.txt too. Yes, I am aware of that and will do that once there is an agreement on the patch itself. At this stage, I just wanted to have a feadback about the change. > > Thanks, > Daisuke Nishimura. > > > The patch is based on the current Linus tree. > > > > Any thoughts? > > --- > > > > From c874f2c1ff1493e49611f19308434e564c2d37c6 Mon Sep 17 00:00:00 2001 > > From: Michal Hocko > > Date: Wed, 10 Nov 2010 13:30:04 +0100 > > Subject: [PATCH] Make swap accounting default behavior configurable > > > > Swap accounting can be configured by CONFIG_CGROUP_MEM_RES_CTLR_SWAP > > configuration option and then it is turned on by default. There is > > a boot option (noswapaccount) which can disable this feature. > > > > This makes it hard for distributors to enable the configuration option > > as this feature leads to a bigger memory consumption and this is a no-go > > for general purpose distribution kernel. On the other hand swap > > accounting may be very usuful for some workloads. > > > > This patch adds a new configuration option which controls the default > > behavior (CGROUP_MEM_RES_CTLR_SWAP_ENABLED) and changes the original > > noswapaccount parameter to swapaccount=true|false which provides > > a more fine grained way to control this feature. > > > > The default behavior is unchanged (if CONFIG_CGROUP_MEM_RES_CTLR_SWAP is > > enabled then CONFIG_CGROUP_MEM_RES_CTLR_SWAP_ENABLED is enabled as well) > > > > Signed-off-by: Michal Hocko > > --- > > init/Kconfig | 13 +++++++++++++ > > mm/memcontrol.c | 19 ++++++++++++++----- > > 2 files changed, 27 insertions(+), 5 deletions(-) > > > > diff --git a/init/Kconfig b/init/Kconfig > > index 88c1046..61d55a7 100644 > > --- a/init/Kconfig > > +++ b/init/Kconfig > > @@ -613,6 +613,19 @@ config CGROUP_MEM_RES_CTLR_SWAP > > if boot option "noswapaccount" is set, swap will not be accounted. > > Now, memory usage of swap_cgroup is 2 bytes per entry. If swap page > > size is 4096bytes, 512k per 1Gbytes of swap. > > +config CGROUP_MEM_RES_CTLR_SWAP_ENABLED > > + bool "Memory Resource Controller Swap Extension enabled by default" > > + depends on CGROUP_MEM_RES_CTLR_SWAP > > + default y > > + help > > + Memory Resource Controller Swap Extension comes with its price in > > + a bigger memory consumption. General purpose distribution kernels > > + which want to enable the feautre but keep it disabled by default > > + and let the user enable it by swapaccount=true boot command line > > + parameter should have this option unselected. > > + For those who want to have the feature enabled by default should > > + select this option (if, for some reason, they need to disable it > > + then swapaccount=false does the trick). > > > > menuconfig CGROUP_SCHED > > bool "Group CPU scheduler" > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > > index 9a99cfa..7c699b3 100644 > > --- a/mm/memcontrol.c > > +++ b/mm/memcontrol.c > > @@ -61,7 +61,14 @@ struct mem_cgroup *root_mem_cgroup __read_mostly; > > #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP > > /* Turned on only when memory cgroup is enabled && really_do_swap_account = 1 */ > > int do_swap_account __read_mostly; > > -static int really_do_swap_account __initdata = 1; /* for remember boot option*/ > > + > > +/* for remember boot option*/ > > +#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP_ENABLED > > +static int really_do_swap_account __initdata = 1; > > +#else > > +static int really_do_swap_account __initdata = 0; > > +#endif > > + > > #else > > #define do_swap_account (0) > > #endif > > @@ -4909,11 +4916,13 @@ struct cgroup_subsys mem_cgroup_subsys = { > > }; > > > > #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP > > - > > -static int __init disable_swap_account(char *s) > > +static int __init enable_swap_account(char *s) > > { > > - really_do_swap_account = 0; > > + if (!s || !strcmp(s, "true")) > > + really_do_swap_account = 1; > > + else if (!strcmp(s, "false")) > > + really_do_swap_account = 0; > > return 1; > > } > > -__setup("noswapaccount", disable_swap_account); > > +__setup("swapaccount", enable_swap_account); > > #endif > > -- > > 1.7.2.3 > > > > > > -- > > Michal Hocko > > L3 team > > SUSE LINUX s.r.o. > > Lihovarska 1060/12 > > 190 00 Praha 9 > > Czech Republic > > > > -- > > To unsubscribe, send a message with 'unsubscribe linux-mm' in > > the body to majordomo@kvack.org. For more info on Linux MM, > > see: http://www.linux-mm.org/ . > > Fight unfair telecom policy in Canada: sign http://dissolvethecrtc.ca/ > > Don't email: email@kvack.org > > -- > To unsubscribe, send a message with 'unsubscribe linux-mm' in > the body to majordomo@kvack.org. For more info on Linux MM, > see: http://www.linux-mm.org/ . > Fight unfair telecom policy in Canada: sign http://dissolvethecrtc.ca/ > Don't email: email@kvack.org -- Michal Hocko L3 team SUSE LINUX s.r.o. Lihovarska 1060/12 190 00 Praha 9 Czech Republic -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/