Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757474Ab0KKAwY (ORCPT ); Wed, 10 Nov 2010 19:52:24 -0500 Received: from TYO202.gate.nec.co.jp ([202.32.8.206]:37788 "EHLO tyo202.gate.nec.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757305Ab0KKAwW (ORCPT ); Wed, 10 Nov 2010 19:52:22 -0500 Date: Thu, 11 Nov 2010 09:46:13 +0900 From: Daisuke Nishimura To: Michal Hocko Cc: linux-mm@kvack.org, KAMEZAWA Hiroyuki , linux-kernel@vger.kernel.org, Daisuke Nishimura Subject: Re: [RFC PATCH] Make swap accounting default behavior configurable Message-Id: <20101111094613.eab2ec0b.nishimura@mxp.nes.nec.co.jp> In-Reply-To: <20101110125154.GC5867@tiehlicka.suse.cz> References: <20101110125154.GC5867@tiehlicka.suse.cz> Organization: NEC Soft, Ltd. X-Mailer: Sylpheed 3.0.3 (GTK+ 2.10.14; i686-pc-mingw32) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5810 Lines: 152 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)]". And you should update Documentation/kernel-parameters.txt too. 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. 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