From a42c390cfa0c2612459d7226ba11612847ca3a64 Mon Sep 17 00:00:00 2001 From: Michal Hocko Date: Wed, 24 Nov 2010 12:57:08 -0800 Subject: [PATCH] cgroups: 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[=1|0] which enhances the original noswapaccount parameter semantic by means of enable/disable logic (defaults to 1 if no value is provided to be still consistent with noswapaccount). 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 Acked-by: Daisuke Nishimura Cc: Balbir Singh Cc: KAMEZAWA Hiroyuki Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Documentation/kernel-parameters.txt | 5 +++++ init/Kconfig | 13 +++++++++++++ mm/memcontrol.c | 21 +++++++++++++++++++-- 3 files changed, 37 insertions(+), 2 deletions(-) diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 92e83e53148..cdd2a6e8a3b 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -2385,6 +2385,11 @@ 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[=0|1] + [KNL] Enable accounting of swap in memory resource + controller if no parameter or 1 is given or disable + it if 0 is given (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 88c10468db4..c9728992a77 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 26218df8d19..7a22b412921 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 @@ -4920,10 +4927,20 @@ struct cgroup_subsys mem_cgroup_subsys = { }; #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP +static int __init enable_swap_account(char *s) +{ + /* consider enabled if no parameter or 1 is given */ + if (!s || !strcmp(s, "1")) + really_do_swap_account = 1; + else if (!strcmp(s, "0")) + really_do_swap_account = 0; + return 1; +} +__setup("swapaccount", enable_swap_account); static int __init disable_swap_account(char *s) { - really_do_swap_account = 0; + enable_swap_account("0"); return 1; } __setup("noswapaccount", disable_swap_account); -- 2.20.1