From: Paul Menage The effects of cgroup_disable=foo are: - foo isn't auto-mounted if you mount all cgroups in a single hierarchy - foo isn't visible as an individually mountable subsystem As a result there will only ever be one call to foo->create(), at init time; all processes will stay in this group, and the group will never be mounted on a visible hierarchy. Any additional effects (e.g. not allocating metadata) are up to the foo subsystem. This doesn't handle early_init subsystems (their "disabled" bit isn't set be, but it could easily be extended to do so if any of the early_init systems wanted it - I think it would just involve some nastier parameter processing since it would occur before the command-line argument parser had been run. Signed-off-by: Balbir Singh Cc: Paul Menage Cc: Balbir Singh Cc: Pavel Emelyanov Cc: KAMEZAWA Hiroyuki Cc: Hugh Dickins Cc: Sudhir Kumar Cc: YAMAMOTO Takashi Cc: David Rientjes Signed-off-by: Andrew Morton --- Documentation/kernel-parameters.txt | 4 ++ include/linux/cgroup.h | 1 kernel/cgroup.c | 45 +++++++++++++++++++++++--- 3 files changed, 45 insertions(+), 5 deletions(-) diff -puN Documentation/kernel-parameters.txt~cgroups-add-cgroup-support-for-enabling-controllers-at-boot-time Documentation/kernel-parameters.txt --- a/Documentation/kernel-parameters.txt~cgroups-add-cgroup-support-for-enabling-controllers-at-boot-time +++ a/Documentation/kernel-parameters.txt @@ -386,6 +386,10 @@ and is between 256 and 4096 characters. ccw_timeout_log [S390] See Documentation/s390/CommonIO for details. + cgroup_disable= [KNL] Disable a particular controller + Format: {name of the controller(s) to disable} + {Currently supported controllers - "memory"} + checkreqprot [SELINUX] Set initial checkreqprot flag value. Format: { "0" | "1" } See security/selinux/Kconfig help text. diff -puN include/linux/cgroup.h~cgroups-add-cgroup-support-for-enabling-controllers-at-boot-time include/linux/cgroup.h --- a/include/linux/cgroup.h~cgroups-add-cgroup-support-for-enabling-controllers-at-boot-time +++ a/include/linux/cgroup.h @@ -294,6 +294,7 @@ struct cgroup_subsys { void (*bind)(struct cgroup_subsys *ss, struct cgroup *root); int subsys_id; int active; + int disabled; int early_init; #define MAX_CGROUP_TYPE_NAMELEN 32 const char *name; diff -puN kernel/cgroup.c~cgroups-add-cgroup-support-for-enabling-controllers-at-boot-time kernel/cgroup.c --- a/kernel/cgroup.c~cgroups-add-cgroup-support-for-enabling-controllers-at-boot-time +++ a/kernel/cgroup.c @@ -771,7 +771,14 @@ static int parse_cgroupfs_options(char * if (!*token) return -EINVAL; if (!strcmp(token, "all")) { - opts->subsys_bits = (1 << CGROUP_SUBSYS_COUNT) - 1; + /* Add all non-disabled subsystems */ + int i; + opts->subsys_bits = 0; + for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) { + struct cgroup_subsys *ss = subsys[i]; + if (!ss->disabled) + opts->subsys_bits |= 1ul << i; + } } else if (!strcmp(token, "noprefix")) { set_bit(ROOT_NOPREFIX, &opts->flags); } else if (!strncmp(token, "release_agent=", 14)) { @@ -789,7 +796,8 @@ static int parse_cgroupfs_options(char * for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) { ss = subsys[i]; if (!strcmp(token, ss->name)) { - set_bit(i, &opts->subsys_bits); + if (!ss->disabled) + set_bit(i, &opts->subsys_bits); break; } } @@ -2643,13 +2651,13 @@ static int proc_cgroupstats_show(struct { int i; - seq_puts(m, "#subsys_name\thierarchy\tnum_cgroups\n"); + seq_puts(m, "#subsys_name\thierarchy\tnum_cgroups\tenabled\n"); mutex_lock(&cgroup_mutex); for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) { struct cgroup_subsys *ss = subsys[i]; - seq_printf(m, "%s\t%lu\t%d\n", + seq_printf(m, "%s\t%lu\t%d\t%d\n", ss->name, ss->root->subsys_bits, - ss->root->number_of_cgroups); + ss->root->number_of_cgroups, !ss->disabled); } mutex_unlock(&cgroup_mutex); return 0; @@ -3053,3 +3061,30 @@ static void cgroup_release_agent(struct spin_unlock(&release_list_lock); mutex_unlock(&cgroup_mutex); } + +static int __init cgroup_disable(char *str) +{ + int i; + + while (*str) { + for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) { + struct cgroup_subsys *ss = subsys[i]; + + if (!strncmp(str, ss->name, strlen(ss->name))) { + ss->disabled = 1; + printk(KERN_INFO "Disabling %s control group" + " subsystem\n", ss->name); + break; + } + } + /* + * Find the next option if any + */ + while (*str && (*str != ',')) + str++; + if (*str == ',') + str++; + } + return 1; +} +__setup("cgroup_disable=", cgroup_disable); _