On Wed, Mar 24, 2021 at 10:37:43AM +0100, Peter Zijlstra wrote: > Should we perhaps take out all SCHED_DEBUG sysctls and move them to > /debug/sched/ ? (along with the existing /debug/sched_{debug,features,preemp} > files) > > Having all that in sysctl and documented gives them far too much sheen > of ABI.
... a little something like this ... --- Subject: sched: Move SCHED_DEBUG to debugfs From: Peter Zijlstra <pet...@infradead.org> Date: Wed Mar 24 11:43:21 CET 2021 Stop polluting sysctl with undocumented knobs that really are debug only, move them all to /debug/sched/. Signed-off-by: Peter Zijlstra (Intel) <pet...@infradead.org> --- include/linux/sched/sysctl.h | 12 --- kernel/sched/core.c | 48 +----------- kernel/sched/debug.c | 169 +++++++++++++++++++++++++++++++++++++++++-- kernel/sched/fair.c | 9 -- kernel/sysctl.c | 116 ----------------------------- 5 files changed, 174 insertions(+), 180 deletions(-) --- a/include/linux/sched/sysctl.h +++ b/include/linux/sched/sysctl.h @@ -26,10 +26,11 @@ int proc_dohung_task_timeout_secs(struct enum { sysctl_hung_task_timeout_secs = 0 }; #endif +extern unsigned int sysctl_sched_child_runs_first; + extern unsigned int sysctl_sched_latency; extern unsigned int sysctl_sched_min_granularity; extern unsigned int sysctl_sched_wakeup_granularity; -extern unsigned int sysctl_sched_child_runs_first; enum sched_tunable_scaling { SCHED_TUNABLESCALING_NONE, @@ -37,7 +38,7 @@ enum sched_tunable_scaling { SCHED_TUNABLESCALING_LINEAR, SCHED_TUNABLESCALING_END, }; -extern enum sched_tunable_scaling sysctl_sched_tunable_scaling; +extern unsigned int sysctl_sched_tunable_scaling; extern unsigned int sysctl_numa_balancing_scan_delay; extern unsigned int sysctl_numa_balancing_scan_period_min; @@ -47,9 +48,6 @@ extern unsigned int sysctl_numa_balancin #ifdef CONFIG_SCHED_DEBUG extern __read_mostly unsigned int sysctl_sched_migration_cost; extern __read_mostly unsigned int sysctl_sched_nr_migrate; - -int sched_proc_update_handler(struct ctl_table *table, int write, - void *buffer, size_t *length, loff_t *ppos); #endif /* @@ -87,10 +85,6 @@ int sched_rt_handler(struct ctl_table *t size_t *lenp, loff_t *ppos); int sysctl_sched_uclamp_handler(struct ctl_table *table, int write, void *buffer, size_t *lenp, loff_t *ppos); -int sysctl_numa_balancing(struct ctl_table *table, int write, void *buffer, - size_t *lenp, loff_t *ppos); -int sysctl_schedstats(struct ctl_table *table, int write, void *buffer, - size_t *lenp, loff_t *ppos); #if defined(CONFIG_ENERGY_MODEL) && defined(CONFIG_CPU_FREQ_GOV_SCHEDUTIL) extern unsigned int sysctl_sched_energy_aware; --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -3612,27 +3612,6 @@ void set_numabalancing_state(bool enable static_branch_disable(&sched_numa_balancing); } -#ifdef CONFIG_PROC_SYSCTL -int sysctl_numa_balancing(struct ctl_table *table, int write, - void *buffer, size_t *lenp, loff_t *ppos) -{ - struct ctl_table t; - int err; - int state = static_branch_likely(&sched_numa_balancing); - - if (write && !capable(CAP_SYS_ADMIN)) - return -EPERM; - - t = *table; - t.data = &state; - err = proc_dointvec_minmax(&t, write, buffer, lenp, ppos); - if (err < 0) - return err; - if (write) - set_numabalancing_state(state); - return err; -} -#endif #endif #ifdef CONFIG_SCHEDSTATS @@ -3640,7 +3619,7 @@ int sysctl_numa_balancing(struct ctl_tab DEFINE_STATIC_KEY_FALSE(sched_schedstats); static bool __initdata __sched_schedstats = false; -static void set_schedstats(bool enabled) +void set_schedstats(bool enabled) { if (enabled) static_branch_enable(&sched_schedstats); @@ -3687,27 +3666,6 @@ static void __init init_schedstats(void) set_schedstats(__sched_schedstats); } -#ifdef CONFIG_PROC_SYSCTL -int sysctl_schedstats(struct ctl_table *table, int write, void *buffer, - size_t *lenp, loff_t *ppos) -{ - struct ctl_table t; - int err; - int state = static_branch_likely(&sched_schedstats); - - if (write && !capable(CAP_SYS_ADMIN)) - return -EPERM; - - t = *table; - t.data = &state; - err = proc_dointvec_minmax(&t, write, buffer, lenp, ppos); - if (err < 0) - return err; - if (write) - set_schedstats(state); - return err; -} -#endif /* CONFIG_PROC_SYSCTL */ #else /* !CONFIG_SCHEDSTATS */ static inline void init_schedstats(void) {} #endif /* CONFIG_SCHEDSTATS */ @@ -5504,9 +5462,11 @@ static const struct file_operations sche .release = single_release, }; +extern struct dentry *debugfs_sched; + static __init int sched_init_debug_dynamic(void) { - debugfs_create_file("sched_preempt", 0644, NULL, NULL, &sched_dynamic_fops); + debugfs_create_file("sched_preempt", 0644, debugfs_sched, NULL, &sched_dynamic_fops); return 0; } late_initcall(sched_init_debug_dynamic); --- a/kernel/sched/debug.c +++ b/kernel/sched/debug.c @@ -169,15 +169,176 @@ static const struct file_operations sche .release = single_release, }; +#ifdef CONFIG_SMP + +extern int sched_update_scaling(void); + +static ssize_t sched_scaling_write(struct file *filp, const char __user *ubuf, + size_t cnt, loff_t *ppos) +{ + char buf[16]; + + if (cnt > 15) + cnt = 15; + + if (copy_from_user(&buf, ubuf, cnt)) + return -EFAULT; + + if (kstrtouint(buf, 10, &sysctl_sched_tunable_scaling)) + return -EINVAL; + + if (sched_update_scaling()) + return -EINVAL; + + *ppos += cnt; + return cnt; +} + +static int sched_scaling_show(struct seq_file *m, void *v) +{ + seq_printf(m, "%d\n", sysctl_sched_tunable_scaling); + return 0; +} + +static int sched_scaling_open(struct inode *inode, struct file *filp) +{ + return single_open(filp, sched_scaling_show, NULL); +} + +static const struct file_operations sched_scaling_fops = { + .open = sched_scaling_open, + .write = sched_scaling_write, + .read = seq_read, + .llseek = seq_lseek, + .release = single_release, +}; + +#ifdef CONFIG_SCHEDSTATS + +extern void set_schedstats(bool enabled); + +static ssize_t sched_stats_write(struct file *filp, const char __user *ubuf, + size_t cnt, loff_t *ppos) +{ + char buf[16]; + bool enabled; + + if (cnt > 15) + cnt = 15; + + if (copy_from_user(&buf, ubuf, cnt)) + return -EFAULT; + + if (kstrtobool(buf, &enabled)) + return -EINVAL; + + set_schedstats(enabled); + + *ppos += cnt; + return cnt; +} + +static int sched_stats_show(struct seq_file *m, void *v) +{ + seq_printf(m, "%d\n", static_key_enabled(&sched_schedstats)); + return 0; +} + +static int sched_stats_open(struct inode *inode, struct file *filp) +{ + return single_open(filp, sched_stats_show, NULL); +} + +static const struct file_operations sched_stats_fops = { + .open = sched_stats_open, + .write = sched_stats_write, + .read = seq_read, + .llseek = seq_lseek, + .release = single_release, +}; + +#endif /* SCHEDSTATS */ +#endif /* SMP */ + +#ifdef CONFIG_NUMA_BALANCING + +static ssize_t sched_numa_write(struct file *filp, const char __user *ubuf, + size_t cnt, loff_t *ppos) +{ + char buf[16]; + bool enabled; + + if (cnt > 15) + cnt = 15; + + if (copy_from_user(&buf, ubuf, cnt)) + return -EFAULT; + + if (kstrtobool(buf, &enabled)) + return -EINVAL; + + set_numabalancing_state(enabled); + + *ppos += cnt; + return cnt; +} + +static int sched_numa_show(struct seq_file *m, void *v) +{ + seq_printf(m, "%d\n", static_key_enabled(&sched_numa_balancing)); + return 0; +} + +static int sched_numa_open(struct inode *inode, struct file *filp) +{ + return single_open(filp, sched_numa_show, NULL); +} + +static const struct file_operations sched_numa_fops = { + .open = sched_numa_open, + .write = sched_numa_write, + .read = seq_read, + .llseek = seq_lseek, + .release = single_release, +}; + +#endif + __read_mostly bool sched_debug_enabled; +struct dentry *debugfs_sched; + static __init int sched_init_debug(void) { - debugfs_create_file("sched_features", 0644, NULL, NULL, - &sched_feat_fops); + struct dentry __maybe_unused *numa; + + debugfs_sched = debugfs_create_dir("sched", NULL); + + debugfs_create_file("features", 0644, debugfs_sched, NULL, &sched_feat_fops); + debugfs_create_bool("debug", 0644, debugfs_sched, &sched_debug_enabled); + + debugfs_create_u32("latency_ns", 0644, debugfs_sched, &sysctl_sched_latency); + debugfs_create_u32("min_granularity_ns", 0644, debugfs_sched, &sysctl_sched_min_granularity); + debugfs_create_u32("wakeup_granularity_ns", 0644, debugfs_sched, &sysctl_sched_wakeup_granularity); + +#ifdef CONFIG_SMP + debugfs_create_file("tunable_scaling", 0644, debugfs_sched, NULL, &sched_scaling_fops); + debugfs_create_u32("migration_cost_ns", 0644, debugfs_sched, &sysctl_sched_migration_cost); + debugfs_create_u32("nr_migrate", 0644, debugfs_sched, &sysctl_sched_nr_migrate); +#ifdef CONFIG_SCHEDSTATS + debugfs_create_file("stats", 0644, debugfs_sched, NULL, &sched_stats_fops); +#endif +#endif + +#ifdef CONFIG_NUMA_BALANCING + numa = debugfs_create_dir("numa", debugfs_sched); - debugfs_create_bool("sched_debug", 0644, NULL, - &sched_debug_enabled); + debugfs_create_file("balancing", 0644, numa, NULL, &sched_numa_fops); + debugfs_create_u32("balancing_scan_delay_ms", 0644, numa, &sysctl_numa_balancing_scan_delay); + debugfs_create_u32("balancing_scan_period_min_ms", 0644, numa, &sysctl_numa_balancing_scan_period_min); + debugfs_create_u32("balancing_scan_period_max_ms", 0644, numa, &sysctl_numa_balancing_scan_period_max); + debugfs_create_u32("balancing_scan_size_mb", 0644, numa, &sysctl_numa_balancing_scan_size); +#endif return 0; } --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -49,7 +49,7 @@ static unsigned int normalized_sysctl_sc * * (default SCHED_TUNABLESCALING_LOG = *(1+ilog(ncpus)) */ -enum sched_tunable_scaling sysctl_sched_tunable_scaling = SCHED_TUNABLESCALING_LOG; +unsigned int sysctl_sched_tunable_scaling = SCHED_TUNABLESCALING_LOG; /* * Minimal preemption granularity for CPU-bound tasks: @@ -627,15 +627,10 @@ struct sched_entity *__pick_last_entity( * Scheduling class statistics methods: */ -int sched_proc_update_handler(struct ctl_table *table, int write, - void *buffer, size_t *lenp, loff_t *ppos) +int sched_update_scaling(void) { - int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos); unsigned int factor = get_update_sysctl_factor(); - if (ret || !write) - return ret; - sched_nr_latency = DIV_ROUND_UP(sysctl_sched_latency, sysctl_sched_min_granularity); --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -184,17 +184,6 @@ static enum sysctl_writes_mode sysctl_wr int sysctl_legacy_va_layout; #endif -#ifdef CONFIG_SCHED_DEBUG -static int min_sched_granularity_ns = 100000; /* 100 usecs */ -static int max_sched_granularity_ns = NSEC_PER_SEC; /* 1 second */ -static int min_wakeup_granularity_ns; /* 0 usecs */ -static int max_wakeup_granularity_ns = NSEC_PER_SEC; /* 1 second */ -#ifdef CONFIG_SMP -static int min_sched_tunable_scaling = SCHED_TUNABLESCALING_NONE; -static int max_sched_tunable_scaling = SCHED_TUNABLESCALING_END-1; -#endif /* CONFIG_SMP */ -#endif /* CONFIG_SCHED_DEBUG */ - #ifdef CONFIG_COMPACTION static int min_extfrag_threshold; static int max_extfrag_threshold = 1000; @@ -1659,111 +1648,6 @@ static struct ctl_table kern_table[] = { .mode = 0644, .proc_handler = proc_dointvec, }, -#ifdef CONFIG_SCHED_DEBUG - { - .procname = "sched_min_granularity_ns", - .data = &sysctl_sched_min_granularity, - .maxlen = sizeof(unsigned int), - .mode = 0644, - .proc_handler = sched_proc_update_handler, - .extra1 = &min_sched_granularity_ns, - .extra2 = &max_sched_granularity_ns, - }, - { - .procname = "sched_latency_ns", - .data = &sysctl_sched_latency, - .maxlen = sizeof(unsigned int), - .mode = 0644, - .proc_handler = sched_proc_update_handler, - .extra1 = &min_sched_granularity_ns, - .extra2 = &max_sched_granularity_ns, - }, - { - .procname = "sched_wakeup_granularity_ns", - .data = &sysctl_sched_wakeup_granularity, - .maxlen = sizeof(unsigned int), - .mode = 0644, - .proc_handler = sched_proc_update_handler, - .extra1 = &min_wakeup_granularity_ns, - .extra2 = &max_wakeup_granularity_ns, - }, -#ifdef CONFIG_SMP - { - .procname = "sched_tunable_scaling", - .data = &sysctl_sched_tunable_scaling, - .maxlen = sizeof(enum sched_tunable_scaling), - .mode = 0644, - .proc_handler = sched_proc_update_handler, - .extra1 = &min_sched_tunable_scaling, - .extra2 = &max_sched_tunable_scaling, - }, - { - .procname = "sched_migration_cost_ns", - .data = &sysctl_sched_migration_cost, - .maxlen = sizeof(unsigned int), - .mode = 0644, - .proc_handler = proc_dointvec, - }, - { - .procname = "sched_nr_migrate", - .data = &sysctl_sched_nr_migrate, - .maxlen = sizeof(unsigned int), - .mode = 0644, - .proc_handler = proc_dointvec, - }, -#ifdef CONFIG_SCHEDSTATS - { - .procname = "sched_schedstats", - .data = NULL, - .maxlen = sizeof(unsigned int), - .mode = 0644, - .proc_handler = sysctl_schedstats, - .extra1 = SYSCTL_ZERO, - .extra2 = SYSCTL_ONE, - }, -#endif /* CONFIG_SCHEDSTATS */ -#endif /* CONFIG_SMP */ -#ifdef CONFIG_NUMA_BALANCING - { - .procname = "numa_balancing_scan_delay_ms", - .data = &sysctl_numa_balancing_scan_delay, - .maxlen = sizeof(unsigned int), - .mode = 0644, - .proc_handler = proc_dointvec, - }, - { - .procname = "numa_balancing_scan_period_min_ms", - .data = &sysctl_numa_balancing_scan_period_min, - .maxlen = sizeof(unsigned int), - .mode = 0644, - .proc_handler = proc_dointvec, - }, - { - .procname = "numa_balancing_scan_period_max_ms", - .data = &sysctl_numa_balancing_scan_period_max, - .maxlen = sizeof(unsigned int), - .mode = 0644, - .proc_handler = proc_dointvec, - }, - { - .procname = "numa_balancing_scan_size_mb", - .data = &sysctl_numa_balancing_scan_size, - .maxlen = sizeof(unsigned int), - .mode = 0644, - .proc_handler = proc_dointvec_minmax, - .extra1 = SYSCTL_ONE, - }, - { - .procname = "numa_balancing", - .data = NULL, /* filled in by handler */ - .maxlen = sizeof(unsigned int), - .mode = 0644, - .proc_handler = sysctl_numa_balancing, - .extra1 = SYSCTL_ZERO, - .extra2 = SYSCTL_ONE, - }, -#endif /* CONFIG_NUMA_BALANCING */ -#endif /* CONFIG_SCHED_DEBUG */ { .procname = "sched_rt_period_us", .data = &sysctl_sched_rt_period,