Stop polluting sysctl, move to debugfs for SCHED_DEBUG stuff.
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
---
kernel/sched/debug.c | 255 ++++++++++--------------------------------------
kernel/sched/sched.h | 2
kernel/sched/topology.c | 1
3 files changed, 59 insertions(+), 199 deletions(-)
--- a/kernel/sched/debug.c
+++ b/kernel/sched/debug.c
@@ -299,6 +299,10 @@ static __init int sched_init_debug(void)
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);
+
+ mutex_lock(&sched_domains_mutex);
+ register_sched_domain_sysctl();
+ mutex_unlock(&sched_domains_mutex);
#endif
#ifdef CONFIG_NUMA_BALANCING
@@ -316,229 +320,87 @@ late_initcall(sched_init_debug);
#ifdef CONFIG_SMP
-#ifdef CONFIG_SYSCTL
-
-static struct ctl_table sd_ctl_dir[] = {
- {
- .procname = "sched_domain",
- .mode = 0555,
- },
- {}
-};
-
-static struct ctl_table sd_ctl_root[] = {
- {
- .procname = "kernel",
- .mode = 0555,
- .child = sd_ctl_dir,
- },
- {}
-};
-
-static struct ctl_table *sd_alloc_ctl_entry(int n)
-{
- struct ctl_table *entry =
- kcalloc(n, sizeof(struct ctl_table), GFP_KERNEL);
-
- return entry;
-}
-
-static void sd_free_ctl_entry(struct ctl_table **tablep)
-{
- struct ctl_table *entry;
-
- /*
- * In the intermediate directories, both the child directory and
- * procname are dynamically allocated and could fail but the mode
- * will always be set. In the lowest directory the names are
- * static strings and all have proc handlers.
- */
- for (entry = *tablep; entry->mode; entry++) {
- if (entry->child)
- sd_free_ctl_entry(&entry->child);
- if (entry->proc_handler == NULL)
- kfree(entry->procname);
- }
-
- kfree(*tablep);
- *tablep = NULL;
-}
-
-static void
-set_table_entry(struct ctl_table *entry,
- const char *procname, void *data, int maxlen,
- umode_t mode, proc_handler *proc_handler)
-{
- entry->procname = procname;
- entry->data = data;
- entry->maxlen = maxlen;
- entry->mode = mode;
- entry->proc_handler = proc_handler;
-}
+static cpumask_var_t sd_sysctl_cpus;
+static struct dentry *sd_dentry;
-static int sd_ctl_doflags(struct ctl_table *table, int write,
- void *buffer, size_t *lenp, loff_t *ppos)
+static int sd_flags_show(struct seq_file *m, void *v)
{
- unsigned long flags = *(unsigned long *)table->data;
- size_t data_size = 0;
- size_t len = 0;
- char *tmp, *buf;
+ unsigned long flags = *(unsigned int *)m->private;
int idx;
- if (write)
- return 0;
-
- for_each_set_bit(idx, &flags, __SD_FLAG_CNT) {
- char *name = sd_flag_debug[idx].name;
-
- /* Name plus whitespace */
- data_size += strlen(name) + 1;
- }
-
- if (*ppos > data_size) {
- *lenp = 0;
- return 0;
- }
-
- buf = kcalloc(data_size + 1, sizeof(*buf), GFP_KERNEL);
- if (!buf)
- return -ENOMEM;
-
for_each_set_bit(idx, &flags, __SD_FLAG_CNT) {
- char *name = sd_flag_debug[idx].name;
-
- len += snprintf(buf + len, strlen(name) + 2, "%s ", name);
+ seq_puts(m, sd_flag_debug[idx].name);
+ seq_puts(m, " ");
}
-
- tmp = buf + *ppos;
- len -= *ppos;
-
- if (len > *lenp)
- len = *lenp;
- if (len)
- memcpy(buffer, tmp, len);
- if (len < *lenp) {
- ((char *)buffer)[len] = '\n';
- len++;
- }
-
- *lenp = len;
- *ppos += len;
-
- kfree(buf);
+ seq_puts(m, "\n");
return 0;
}
-static struct ctl_table *
-sd_alloc_ctl_domain_table(struct sched_domain *sd)
-{
- struct ctl_table *table = sd_alloc_ctl_entry(9);
-
- if (table == NULL)
- return NULL;
-
- set_table_entry(&table[0], "min_interval", &sd->min_interval, sizeof(long), 0644, proc_doulongvec_minmax);
- set_table_entry(&table[1], "max_interval", &sd->max_interval, sizeof(long), 0644, proc_doulongvec_minmax);
- set_table_entry(&table[2], "busy_factor", &sd->busy_factor, sizeof(int), 0644, proc_dointvec_minmax);
- set_table_entry(&table[3], "imbalance_pct", &sd->imbalance_pct, sizeof(int), 0644, proc_dointvec_minmax);
- set_table_entry(&table[4], "cache_nice_tries", &sd->cache_nice_tries, sizeof(int), 0644, proc_dointvec_minmax);
- set_table_entry(&table[5], "flags", &sd->flags, sizeof(int), 0444, sd_ctl_doflags);
- set_table_entry(&table[6], "max_newidle_lb_cost", &sd->max_newidle_lb_cost, sizeof(long), 0644, proc_doulongvec_minmax);
- set_table_entry(&table[7], "name", sd->name, CORENAME_MAX_SIZE, 0444, proc_dostring);
- /* &table[8] is terminator */
-
- return table;
-}
-
-static struct ctl_table *sd_alloc_ctl_cpu_table(int cpu)
+static int sd_flags_open(struct inode *inode, struct file *file)
{
- struct ctl_table *entry, *table;
- struct sched_domain *sd;
- int domain_num = 0, i;
- char buf[32];
-
- for_each_domain(cpu, sd)
- domain_num++;
- entry = table = sd_alloc_ctl_entry(domain_num + 1);
- if (table == NULL)
- return NULL;
-
- i = 0;
- for_each_domain(cpu, sd) {
- snprintf(buf, 32, "domain%d", i);
- entry->procname = kstrdup(buf, GFP_KERNEL);
- entry->mode = 0555;
- entry->child = sd_alloc_ctl_domain_table(sd);
- entry++;
- i++;
- }
- return table;
+ return single_open(file, sd_flags_show, inode->i_private);
}
-static cpumask_var_t sd_sysctl_cpus;
-static struct ctl_table_header *sd_sysctl_header;
+static const struct file_operations sd_flags_fops = {
+ .open = sd_flags_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = single_release,
+};
-void register_sched_domain_sysctl(void)
+static void register_sd(struct sched_domain *sd, struct dentry *parent)
{
- static struct ctl_table *cpu_entries;
- static struct ctl_table **cpu_idx;
- static bool init_done = false;
- char buf[32];
- int i;
-
- if (!cpu_entries) {
- cpu_entries = sd_alloc_ctl_entry(num_possible_cpus() + 1);
- if (!cpu_entries)
- return;
+#define SDM(type, mode, member) \
+ debugfs_create_##type(#member, mode, parent, &sd->member)
- WARN_ON(sd_ctl_dir[0].child);
- sd_ctl_dir[0].child = cpu_entries;
- }
+ SDM(ulong, 0644, min_interval);
+ SDM(ulong, 0644, max_interval);
+ SDM(u64, 0644, max_newidle_lb_cost);
+ SDM(u32, 0644, busy_factor);
+ SDM(u32, 0644, imbalance_pct);
+ SDM(u32, 0644, cache_nice_tries);
+// SDM(x32, 0444, flags);
+ SDM(str, 0444, name);
- if (!cpu_idx) {
- struct ctl_table *e = cpu_entries;
+#undef SDM
- cpu_idx = kcalloc(nr_cpu_ids, sizeof(struct ctl_table*), GFP_KERNEL);
- if (!cpu_idx)
- return;
+ debugfs_create_file("flags", 0444, parent, &sd->flags, &sd_flags_fops);
+}
- /* deal with sparse possible map */
- for_each_possible_cpu(i) {
- cpu_idx[i] = e;
- e++;
- }
- }
+void register_sched_domain_sysctl(void)
+{
+ int cpu, i;
if (!cpumask_available(sd_sysctl_cpus)) {
if (!alloc_cpumask_var(&sd_sysctl_cpus, GFP_KERNEL))
return;
- }
-
- if (!init_done) {
- init_done = true;
- /* init to possible to not have holes in @cpu_entries */
cpumask_copy(sd_sysctl_cpus, cpu_possible_mask);
}
- for_each_cpu(i, sd_sysctl_cpus) {
- struct ctl_table *e = cpu_idx[i];
+ if (!sd_dentry)
+ sd_dentry = debugfs_create_dir("domains", debugfs_sched);
- if (e->child)
- sd_free_ctl_entry(&e->child);
+ for_each_cpu(cpu, sd_sysctl_cpus) {
+ struct sched_domain *sd;
+ struct dentry *d_cpu;
+ char buf[32];
+
+ snprintf(buf, sizeof(buf), "cpu%d", cpu);
+ debugfs_remove(debugfs_lookup(buf, sd_dentry));
+ d_cpu = debugfs_create_dir(buf, sd_dentry);
+
+ i = 0;
+ for_each_domain(cpu, sd) {
+ struct dentry *d_sd;
- if (!e->procname) {
- snprintf(buf, 32, "cpu%d", i);
- e->procname = kstrdup(buf, GFP_KERNEL);
- }
- e->mode = 0555;
- e->child = sd_alloc_ctl_cpu_table(i);
+ snprintf(buf, sizeof(buf), "domain%d", i);
+ d_sd = debugfs_create_dir(buf, d_cpu);
- __cpumask_clear_cpu(i, sd_sysctl_cpus);
+ register_sd(sd, d_sd);
+ i++;
+ }
}
-
- WARN_ON(sd_sysctl_header);
- sd_sysctl_header = register_sysctl_table(sd_ctl_root);
}
void dirty_sched_domain_sysctl(int cpu)
@@ -547,13 +409,12 @@ void dirty_sched_domain_sysctl(int cpu)
__cpumask_set_cpu(cpu, sd_sysctl_cpus);
}
-/* may be called multiple times per register */
void unregister_sched_domain_sysctl(void)
{
- unregister_sysctl_table(sd_sysctl_header);
- sd_sysctl_header = NULL;
+ debugfs_remove(sd_dentry);
+ sd_dentry = NULL;
}
-#endif /* CONFIG_SYSCTL */
+
#endif /* CONFIG_SMP */
#ifdef CONFIG_FAIR_GROUP_SCHED
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -1553,7 +1553,7 @@ static inline unsigned int group_first_c
extern int group_balance_cpu(struct sched_group *sg);
-#if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL)
+#ifdef CONFIG_SCHED_DEBUG
void register_sched_domain_sysctl(void);
void dirty_sched_domain_sysctl(int cpu);
void unregister_sched_domain_sysctl(void);
--- a/kernel/sched/topology.c
+++ b/kernel/sched/topology.c
@@ -2223,7 +2223,6 @@ int sched_init_domains(const struct cpum
doms_cur = &fallback_doms;
cpumask_and(doms_cur[0], cpu_map, housekeeping_cpumask(HK_FLAG_DOMAIN));
err = build_sched_domains(doms_cur[0], NULL);
- register_sched_domain_sysctl();
return err;
}
On 26/03/2021 11:33, Peter Zijlstra wrote:
> Stop polluting sysctl, move to debugfs for SCHED_DEBUG stuff.
>
> Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
> ---
> kernel/sched/debug.c | 255 ++++++++++--------------------------------------
> kernel/sched/sched.h | 2
> kernel/sched/topology.c | 1
> 3 files changed, 59 insertions(+), 199 deletions(-)
Reviewed-by: Dietmar Eggemann <[email protected]>
[...]
> +#define SDM(type, mode, member) \
> + debugfs_create_##type(#member, mode, parent, &sd->member)
>
> - WARN_ON(sd_ctl_dir[0].child);
> - sd_ctl_dir[0].child = cpu_entries;
> - }
> + SDM(ulong, 0644, min_interval);
> + SDM(ulong, 0644, max_interval);
> + SDM(u64, 0644, max_newidle_lb_cost);
> + SDM(u32, 0644, busy_factor);
> + SDM(u32, 0644, imbalance_pct);
> + SDM(u32, 0644, cache_nice_tries);
> +// SDM(x32, 0444, flags);
Can be removed.
> + SDM(str, 0444, name);
>
> - if (!cpu_idx) {
> - struct ctl_table *e = cpu_entries;
> +#undef SDM
>
> - cpu_idx = kcalloc(nr_cpu_ids, sizeof(struct ctl_table*), GFP_KERNEL);
> - if (!cpu_idx)
> - return;
> + debugfs_create_file("flags", 0444, parent, &sd->flags, &sd_flags_fops);
> +}
[...]
On 26/03/21 11:33, Peter Zijlstra wrote:
> Stop polluting sysctl, move to debugfs for SCHED_DEBUG stuff.
>
> Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
> ---
> kernel/sched/debug.c | 255 ++++++++++--------------------------------------
> kernel/sched/sched.h | 2
> kernel/sched/topology.c | 1
> 3 files changed, 59 insertions(+), 199 deletions(-)
>
I do very much like to see a simple pair of seq_puts() replacing the
mess I put in there!
One comment below.
> --- a/kernel/sched/debug.c
> +++ b/kernel/sched/debug.c
> +void register_sched_domain_sysctl(void)
> +{
> + int cpu, i;
>
> if (!cpumask_available(sd_sysctl_cpus)) {
> if (!alloc_cpumask_var(&sd_sysctl_cpus, GFP_KERNEL))
> return;
> - }
> -
> - if (!init_done) {
> - init_done = true;
> - /* init to possible to not have holes in @cpu_entries */
> cpumask_copy(sd_sysctl_cpus, cpu_possible_mask);
> }
>
> - for_each_cpu(i, sd_sysctl_cpus) {
> - struct ctl_table *e = cpu_idx[i];
> + if (!sd_dentry)
> + sd_dentry = debugfs_create_dir("domains", debugfs_sched);
>
> - if (e->child)
> - sd_free_ctl_entry(&e->child);
> + for_each_cpu(cpu, sd_sysctl_cpus) {
> + struct sched_domain *sd;
> + struct dentry *d_cpu;
> + char buf[32];
> +
> + snprintf(buf, sizeof(buf), "cpu%d", cpu);
> + debugfs_remove(debugfs_lookup(buf, sd_dentry));
> + d_cpu = debugfs_create_dir(buf, sd_dentry);
> +
> + i = 0;
> + for_each_domain(cpu, sd) {
> + struct dentry *d_sd;
>
> - if (!e->procname) {
> - snprintf(buf, 32, "cpu%d", i);
> - e->procname = kstrdup(buf, GFP_KERNEL);
> - }
> - e->mode = 0555;
> - e->child = sd_alloc_ctl_cpu_table(i);
> + snprintf(buf, sizeof(buf), "domain%d", i);
> + d_sd = debugfs_create_dir(buf, d_cpu);
>
> - __cpumask_clear_cpu(i, sd_sysctl_cpus);
That seems to be the only place we cleared a CPU in that cpumask, and I
don't see its replacement, which would go against:
bbdacdfed2f5 ("sched/debug: Optimize sched_domain sysctl generation")
With my very limited understanding of debugfs and sysctl, it seems that
before we would have some stuff saved in sd_ctl_table and free/reinit just
the bits we needed. With debugfs_remove(), I think we wipe everything
clean, or did I read that wrong?
On Wed, Apr 07, 2021 at 11:46:32AM +0100, Valentin Schneider wrote:
> > - __cpumask_clear_cpu(i, sd_sysctl_cpus);
>
> That seems to be the only place we cleared a CPU in that cpumask, and I
> don't see its replacement
Yeah, oops :-) Lemme go fix that. Thanks!