Hi Andrew, could you consider the following patch for the Linus tree, please? The discussion took place in this email thread http://lkml.org/lkml/2010/11/10/114. The patch is based on top of 151f52f09c572 commit in the Linus tree. Please let me know if there I should route this patch through somebody else. Thanks! --- >From 30238aaec758988493af793939f14b0ba83dc4b3 Mon Sep 17 00:00:00 2001 From: Michal Hocko <mhocko@xxxxxxx> 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). If the option is selected then the feature is turned on by default. It also adds a new boot parameter swapaccount which (contrary to noswapaccount) enables the feature. (I would consider swapaccount=yes|no semantic with removed noswapaccount parameter much better but this parameter is kind of API which might be in use and unexpected breakage is no-go.) 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 <mhocko@xxxxxxx> Acked-by: Daisuke Nishimura <nishimura@xxxxxxxxxxxxxxxxx> --- Documentation/kernel-parameters.txt | 3 +++ init/Kconfig | 13 +++++++++++++ mm/memcontrol.c | 15 ++++++++++++++- 3 files changed, 30 insertions(+), 1 deletions(-) diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index ed45e98..14eafa5 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -2385,6 +2385,9 @@ and is between 256 and 4096 characters. It is defined in the file improve throughput, but will also increase the amount of memory reserved for use by the client. + swapaccount [KNL] Enable accounting of swap in memory resource + controller. (See Documentation/cgroups/memory.txt) + swiotlb= [IA-64] Number of I/O TLB slabs switches= [HW,M68k] diff --git a/init/Kconfig b/init/Kconfig index 88c1046..c972899 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 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 noswapaccount does the trick). menuconfig CGROUP_SCHED bool "Group CPU scheduler" diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 9a99cfa..4f479fe 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 @@ -4909,6 +4916,12 @@ struct cgroup_subsys mem_cgroup_subsys = { }; #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP +static int __init enable_swap_account(char *s) +{ + really_do_swap_account = 1; + return 1; +} +__setup("swapaccount", enable_swap_account); static int __init disable_swap_account(char *s) { -- 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@xxxxxxxxxx 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: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>