diff options
| -rw-r--r-- | Documentation/admin-guide/kernel-parameters.txt | 9 | ||||
| -rw-r--r-- | include/linux/cgroup-defs.h | 1 | ||||
| -rw-r--r-- | include/linux/cgroup.h | 7 | ||||
| -rw-r--r-- | kernel/cgroup/cgroup.c | 48 | ||||
| -rw-r--r-- | kernel/sched/psi.c | 30 |
5 files changed, 80 insertions, 15 deletions
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index cb89dbdedc46..653c62142f07 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -497,16 +497,21 @@ ccw_timeout_log [S390] See Documentation/s390/common_io.rst for details. - cgroup_disable= [KNL] Disable a particular controller - Format: {name of the controller(s) to disable} + cgroup_disable= [KNL] Disable a particular controller or optional feature + Format: {name of the controller(s) or feature(s) to disable} 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 + - if foo is an optional feature then the feature is + disabled and corresponding cgroup files are not + created {Currently only "memory" controller deal with this and cut the overhead, others just disable the usage. So only cgroup_disable=memory is actually worthy} + Specifying "pressure" disables per-cgroup pressure + stall information accounting feature cgroup_no_v1= [KNL] Disable cgroup controllers and named hierarchies in v1 Format: { { controller | "all" | "named" } diff --git a/include/linux/cgroup-defs.h b/include/linux/cgroup-defs.h index 1a1f3e8faceb..e1c705fdfa7c 100644 --- a/include/linux/cgroup-defs.h +++ b/include/linux/cgroup-defs.h @@ -113,6 +113,7 @@ enum { CFTYPE_NO_PREFIX = (1 << 3), /* (DON'T USE FOR NEW FILES) no subsys prefix */ CFTYPE_WORLD_WRITABLE = (1 << 4), /* (DON'T USE FOR NEW FILES) S_IWUGO */ CFTYPE_DEBUG = (1 << 5), /* create when cgroup_debug */ + CFTYPE_PRESSURE = (1 << 6), /* only if pressure feature is enabled */ /* internal flags, do not use outside cgroup core proper */ __CFTYPE_ONLY_ON_DFL = (1 << 16), /* only on default hierarchy */ diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h index 9047fa853dd3..2cc237e3e8b3 100644 --- a/include/linux/cgroup.h +++ b/include/linux/cgroup.h @@ -676,6 +676,8 @@ static inline struct psi_group *cgroup_psi(struct cgroup *cgrp) return &cgrp->psi; } +bool cgroup_psi_enabled(void); + static inline void cgroup_init_kthreadd(void) { /* @@ -735,6 +737,11 @@ static inline struct psi_group *cgroup_psi(struct cgroup *cgrp) return NULL; } +static inline bool cgroup_psi_enabled(void) +{ + return false; +} + static inline bool task_under_cgroup_hierarchy(struct task_struct *task, struct cgroup *ancestor) { diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index 74e3cc801615..e13a37f4acab 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -209,6 +209,22 @@ struct cgroup_namespace init_cgroup_ns = { static struct file_system_type cgroup2_fs_type; static struct cftype cgroup_base_files[]; +/* cgroup optional features */ +enum cgroup_opt_features { +#ifdef CONFIG_PSI + OPT_FEATURE_PRESSURE, +#endif + OPT_FEATURE_COUNT +}; + +static const char *cgroup_opt_feature_names[OPT_FEATURE_COUNT] = { +#ifdef CONFIG_PSI + "pressure", +#endif +}; + +static u16 cgroup_feature_disable_mask __read_mostly; + static int cgroup_apply_control(struct cgroup *cgrp); static void cgroup_finalize_control(struct cgroup *cgrp, int ret); static void css_task_iter_skip(struct css_task_iter *it, @@ -3631,6 +3647,18 @@ static void cgroup_pressure_release(struct kernfs_open_file *of) { psi_trigger_replace(&of->priv, NULL); } + +bool cgroup_psi_enabled(void) +{ + return (cgroup_feature_disable_mask & (1 << OPT_FEATURE_PRESSURE)) == 0; +} + +#else /* CONFIG_PSI */ +bool cgroup_psi_enabled(void) +{ + return false; +} + #endif /* CONFIG_PSI */ static int cgroup_freeze_show(struct seq_file *seq, void *v) @@ -3955,6 +3983,8 @@ static int cgroup_addrm_files(struct cgroup_subsys_state *css, restart: for (cft = cfts; cft != cft_end && cft->name[0] != '\0'; cft++) { /* does cft->flags tell us to skip this file on @cgrp? */ + if ((cft->flags & CFTYPE_PRESSURE) && !cgroup_psi_enabled()) + continue; if ((cft->flags & __CFTYPE_ONLY_ON_DFL) && !cgroup_on_dfl(cgrp)) continue; if ((cft->flags & __CFTYPE_NOT_ON_DFL) && cgroup_on_dfl(cgrp)) @@ -4032,6 +4062,9 @@ static int cgroup_init_cftypes(struct cgroup_subsys *ss, struct cftype *cfts) WARN_ON(cft->ss || cft->kf_ops); + if ((cft->flags & CFTYPE_PRESSURE) && !cgroup_psi_enabled()) + continue; + if (cft->seq_start) kf_ops = &cgroup_kf_ops; else @@ -4945,6 +4978,7 @@ static struct cftype cgroup_base_files[] = { #ifdef CONFIG_PSI { .name = "io.pressure", + .flags = CFTYPE_PRESSURE, .seq_show = cgroup_io_pressure_show, .write = cgroup_io_pressure_write, .poll = cgroup_pressure_poll, @@ -4952,6 +4986,7 @@ static struct cftype cgroup_base_files[] = { }, { .name = "memory.pressure", + .flags = CFTYPE_PRESSURE, .seq_show = cgroup_memory_pressure_show, .write = cgroup_memory_pressure_write, .poll = cgroup_pressure_poll, @@ -4959,6 +4994,7 @@ static struct cftype cgroup_base_files[] = { }, { .name = "cpu.pressure", + .flags = CFTYPE_PRESSURE, .seq_show = cgroup_cpu_pressure_show, .write = cgroup_cpu_pressure_write, .poll = cgroup_pressure_poll, @@ -6313,6 +6349,15 @@ static int __init cgroup_disable(char *str) pr_info("Disabling %s control group subsystem\n", ss->name); } + + for (i = 0; i < OPT_FEATURE_COUNT; i++) { + if (strcmp(token, cgroup_opt_feature_names[i])) + continue; + cgroup_feature_disable_mask |= 1 << i; + pr_info("Disabling %s control group feature\n", + cgroup_opt_feature_names[i]); + break; + } } return 1; } @@ -6611,6 +6656,9 @@ static ssize_t show_delegatable_files(struct cftype *files, char *buf, if (!(cft->flags & CFTYPE_NS_DELEGATABLE)) continue; + if ((cft->flags & CFTYPE_PRESSURE) && !cgroup_psi_enabled()) + continue; + if (prefix) ret += snprintf(buf + ret, size - ret, "%s.", prefix); diff --git a/kernel/sched/psi.c b/kernel/sched/psi.c index cc25a3cff41f..b773cae4c24b 100644 --- a/kernel/sched/psi.c +++ b/kernel/sched/psi.c @@ -148,6 +148,7 @@ static int psi_bug __read_mostly; DEFINE_STATIC_KEY_FALSE(psi_disabled); +DEFINE_STATIC_KEY_TRUE(psi_cgroups_enabled); #ifdef CONFIG_PSI_DEFAULT_DISABLED static bool psi_enable; @@ -211,6 +212,9 @@ void __init psi_init(void) return; } + if (!cgroup_psi_enabled()) + static_branch_disable(&psi_cgroups_enabled); + psi_period = jiffies_to_nsecs(PSI_FREQ); group_init(&psi_system); } @@ -744,23 +748,23 @@ static void psi_group_change(struct psi_group *group, int cpu, static struct psi_group *iterate_groups(struct task_struct *task, void **iter) { + if (*iter == &psi_system) + return NULL; + #ifdef CONFIG_CGROUPS - struct cgroup *cgroup = NULL; + if (static_branch_likely(&psi_cgroups_enabled)) { + struct cgroup *cgroup = NULL; - if (!*iter) - cgroup = task->cgroups->dfl_cgrp; - else if (*iter == &psi_system) - return NULL; - else - cgroup = cgroup_parent(*iter); + if (!*iter) + cgroup = task->cgroups->dfl_cgrp; + else + cgroup = cgroup_parent(*iter); - if (cgroup && cgroup_parent(cgroup)) { - *iter = cgroup; - return cgroup_psi(cgroup); + if (cgroup && cgroup_parent(cgroup)) { + *iter = cgroup; + return cgroup_psi(cgroup); + } } -#else - if (*iter) - return NULL; #endif *iter = &psi_system; return &psi_system; |