sched,debug: Convert sysctl sched_domains to debugfs
authorPeter Zijlstra <peterz@infradead.org>
Thu, 25 Mar 2021 10:31:20 +0000 (11:31 +0100)
committerPeter Zijlstra <peterz@infradead.org>
Fri, 16 Apr 2021 15:06:35 +0000 (17:06 +0200)
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
kernel/sched/debug.c
kernel/sched/sched.h
kernel/sched/topology.c

index bdd344f..b25de7b 100644 (file)
@@ -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
@@ -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)
@@ -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
index c312389..55232db 100644 (file)
@@ -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);
index d1aec24..c343aed 100644 (file)
@@ -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;
 }
@@ -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();
 
@@ -2389,7 +2385,7 @@ match3:
        dattr_cur = dattr_new;
        ndoms_cur = ndoms_new;
 
-       register_sched_domain_sysctl();
+       update_sched_domain_debugfs();
 }
 
 /*