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sched,debug: Convert sysctl sched_domains to debugfs
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Stop polluting sysctl, move to debugfs for SCHED_DEBUG stuff.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Reviewed-by: Valentin Schneider <valentin.schneider@arm.com>
Tested-by: Valentin Schneider <valentin.schneider@arm.com>
Link: https://lkml.kernel.org/r/YHgB/s4KCBQ1ifdm@hirez.programming.kicks-ass.net
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Peter Zijlstra committed Apr 16, 2021
1 parent 9af0440 commit 3b87f13
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Showing 3 changed files with 59 additions and 211 deletions.
254 changes: 55 additions & 199 deletions kernel/sched/debug.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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);
update_sched_domain_debugfs();
mutex_unlock(&sched_domains_mutex);
#endif

#ifdef CONFIG_NUMA_BALANCING
Expand All @@ -316,229 +320,88 @@ 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);
}

tmp = buf + *ppos;
len -= *ppos;

if (len > *lenp)
len = *lenp;
if (len)
memcpy(buffer, tmp, len);
if (len < *lenp) {
((char *)buffer)[len] = '\n';
len++;
seq_puts(m, sd_flag_debug[idx].name);
seq_puts(m, " ");
}

*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;
#define SDM(type, mode, member) \
debugfs_create_##type(#member, mode, parent, &sd->member)

if (!cpu_entries) {
cpu_entries = sd_alloc_ctl_entry(num_possible_cpus() + 1);
if (!cpu_entries)
return;

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(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 update_sched_domain_debugfs(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);

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);

if (e->child)
sd_free_ctl_entry(&e->child);
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);
snprintf(buf, sizeof(buf), "domain%d", i);
d_sd = debugfs_create_dir(buf, d_cpu);

register_sd(sd, d_sd);
i++;
}
e->mode = 0555;
e->child = sd_alloc_ctl_cpu_table(i);

__cpumask_clear_cpu(i, sd_sysctl_cpus);
__cpumask_clear_cpu(cpu, sd_sysctl_cpus);
}

WARN_ON(sd_sysctl_header);
sd_sysctl_header = register_sysctl_table(sd_ctl_root);
}

void dirty_sched_domain_sysctl(int cpu)
Expand All @@ -547,13 +410,6 @@ 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;
}
#endif /* CONFIG_SYSCTL */
#endif /* CONFIG_SMP */

#ifdef CONFIG_FAIR_GROUP_SCHED
Expand Down
10 changes: 3 additions & 7 deletions kernel/sched/sched.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1552,20 +1552,16 @@ static inline unsigned int group_first_cpu(struct sched_group *group)

extern int group_balance_cpu(struct sched_group *sg);

#if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL)
void register_sched_domain_sysctl(void);
#ifdef CONFIG_SCHED_DEBUG
void update_sched_domain_debugfs(void);
void dirty_sched_domain_sysctl(int cpu);
void unregister_sched_domain_sysctl(void);
#else
static inline void register_sched_domain_sysctl(void)
static inline void update_sched_domain_debugfs(void)
{
}
static inline void dirty_sched_domain_sysctl(int cpu)
{
}
static inline void unregister_sched_domain_sysctl(void)
{
}
#endif

extern int sched_update_scaling(void);
Expand Down
6 changes: 1 addition & 5 deletions kernel/sched/topology.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -2223,7 +2223,6 @@ int sched_init_domains(const struct cpumask *cpu_map)
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;
}
Expand Down Expand Up @@ -2298,9 +2297,6 @@ void partition_sched_domains_locked(int ndoms_new, cpumask_var_t doms_new[],

lockdep_assert_held(&sched_domains_mutex);

/* Always unregister in case we don't destroy any domains: */
unregister_sched_domain_sysctl();

/* Let the architecture update CPU core mappings: */
new_topology = arch_update_cpu_topology();

Expand Down Expand Up @@ -2389,7 +2385,7 @@ void partition_sched_domains_locked(int ndoms_new, cpumask_var_t doms_new[],
dattr_cur = dattr_new;
ndoms_cur = ndoms_new;

register_sched_domain_sysctl();
update_sched_domain_debugfs();
}

/*
Expand Down

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