Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755933Ab0KJMv6 (ORCPT ); Wed, 10 Nov 2010 07:51:58 -0500 Received: from cantor.suse.de ([195.135.220.2]:47269 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755784Ab0KJMv5 (ORCPT ); Wed, 10 Nov 2010 07:51:57 -0500 Date: Wed, 10 Nov 2010 13:51:54 +0100 From: Michal Hocko To: linux-mm@kvack.org Cc: KAMEZAWA Hiroyuki , linux-kernel@vger.kernel.org Subject: [RFC PATCH] Make swap accounting default behavior configurable Message-ID: <20101110125154.GC5867@tiehlicka.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline 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: 4799 Lines: 131 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. 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. 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