From 66b3e537b50cd2b46b71edb6ffeef633d1224d10 Mon Sep 17 00:00:00 2001 From: Phil Elwell Date: Mon, 27 Nov 2017 17:14:54 +0000 Subject: [PATCH] cgroup: Disable cgroup "memory" by default Some Raspberry Pis have limited RAM and most users won't use the cgroup memory support so it is disabled by default. Enable with: cgroup_enable=memory See: https://github.com/raspberrypi/linux/issues/1950 Signed-off-by: Phil Elwell --- kernel/cgroup/cgroup.c | 38 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 38 insertions(+) --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -5219,6 +5219,9 @@ int __init cgroup_init_early(void) return 0; } +static u16 cgroup_enable_mask __initdata; +static int __init cgroup_disable(char *str); + /** * cgroup_init - cgroup initialization * @@ -5256,6 +5259,12 @@ int __init cgroup_init(void) mutex_unlock(&cgroup_mutex); + /* + * Apply an implicit disable, knowing that an explicit enable will + * prevent if from doing anything. + */ + cgroup_disable("memory"); + for_each_subsys(ss, ssid) { if (ss->early_init) { struct cgroup_subsys_state *css = @@ -5637,6 +5646,10 @@ static int __init cgroup_disable(char *s strcmp(token, ss->legacy_name)) continue; + /* An explicit cgroup_enable overrides a disable */ + if (cgroup_enable_mask & (1 << i)) + continue; + static_branch_disable(cgroup_subsys_enabled_key[i]); pr_info("Disabling %s control group subsystem\n", ss->name); @@ -5646,6 +5659,31 @@ static int __init cgroup_disable(char *s } __setup("cgroup_disable=", cgroup_disable); +static int __init cgroup_enable(char *str) +{ + struct cgroup_subsys *ss; + char *token; + int i; + + while ((token = strsep(&str, ",")) != NULL) { + if (!*token) + continue; + + for_each_subsys(ss, i) { + if (strcmp(token, ss->name) && + strcmp(token, ss->legacy_name)) + continue; + + cgroup_enable_mask |= 1 << i; + static_branch_enable(cgroup_subsys_enabled_key[i]); + pr_info("Enabling %s control group subsystem\n", + ss->name); + } + } + return 1; +} +__setup("cgroup_enable=", cgroup_enable); + /** * css_tryget_online_from_dir - get corresponding css from a cgroup dentry * @dentry: directory dentry of interest