perf/core: Move perf_event sysctls into kernel/events

Move ctl tables to two files:

 - perf_event_{paranoid,mlock_kb,max_sample_rate} and
   perf_cpu_time_max_percent into kernel/events/core.c

 - perf_event_max_{stack,context_per_stack} into
   kernel/events/callchain.c

Make static variables and functions that are fully contained in core.c
and callchain.cand remove them from include/linux/perf_event.h.
Additionally six_hundred_forty_kb is moved to callchain.c.

Two new sysctl tables are added ({callchain,events_core}_sysctl_table)
with their respective sysctl registration functions.

This is part of a greater effort to move ctl tables into their
respective subsystems which will reduce the merge conflicts in
kerenel/sysctl.c.

Signed-off-by: Joel Granados <joel.granados@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20250218-jag-mv_ctltables-v1-5-cd3698ab8d29@kernel.org

diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 2d07bc1193f3ae718e6952b67f4a166588ccab2c..c4525bae2fe9f98f731234d560e74f6dd499df46 100644 (file)
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -1652,19 +1652,10 @@ static inline int perf_callchain_store(struct perf_callchain_entry_ctx *ctx, u64
 }
 
 extern int sysctl_perf_event_paranoid;
-extern int sysctl_perf_event_mlock;
 extern int sysctl_perf_event_sample_rate;
-extern int sysctl_perf_cpu_time_max_percent;
 
 extern void perf_sample_event_took(u64 sample_len_ns);
 
-int perf_event_max_sample_rate_handler(const struct ctl_table *table, int write,
-               void *buffer, size_t *lenp, loff_t *ppos);
-int perf_cpu_time_max_percent_handler(const struct ctl_table *table, int write,
-               void *buffer, size_t *lenp, loff_t *ppos);
-int perf_event_max_stack_handler(const struct ctl_table *table, int write,
-               void *buffer, size_t *lenp, loff_t *ppos);
-
 /* Access to perf_event_open(2) syscall. */
 #define PERF_SECURITY_OPEN             0
 

diff --git a/kernel/events/callchain.c b/kernel/events/callchain.c
index 8a47e52a454f47a5087c07eab5926bc91fe98f2d..6c83ad674d01048e29f97492f08d06503ba7282e 100644 (file)
--- a/kernel/events/callchain.c
+++ b/kernel/events/callchain.c
@@ -22,6 +22,7 @@ struct callchain_cpus_entries {
 
 int sysctl_perf_event_max_stack __read_mostly = PERF_MAX_STACK_DEPTH;
 int sysctl_perf_event_max_contexts_per_stack __read_mostly = PERF_MAX_CONTEXTS_PER_STACK;
+static const int six_hundred_forty_kb = 640 * 1024;
 
 static inline size_t perf_callchain_entry__sizeof(void)
 {
@@ -266,12 +267,8 @@ exit_put:
        return entry;
 }
 
-/*
- * Used for sysctl_perf_event_max_stack and
- * sysctl_perf_event_max_contexts_per_stack.
- */
-int perf_event_max_stack_handler(const struct ctl_table *table, int write,
-                                void *buffer, size_t *lenp, loff_t *ppos)
+static int perf_event_max_stack_handler(const struct ctl_table *table, int write,
+                                       void *buffer, size_t *lenp, loff_t *ppos)
 {
        int *value = table->data;
        int new_value = *value, ret;
@@ -292,3 +289,32 @@ int perf_event_max_stack_handler(const struct ctl_table *table, int write,
 
        return ret;
 }
+
+static const struct ctl_table callchain_sysctl_table[] = {
+       {
+               .procname       = "perf_event_max_stack",
+               .data           = &sysctl_perf_event_max_stack,
+               .maxlen         = sizeof(sysctl_perf_event_max_stack),
+               .mode           = 0644,
+               .proc_handler   = perf_event_max_stack_handler,
+               .extra1         = SYSCTL_ZERO,
+               .extra2         = (void *)&six_hundred_forty_kb,
+       },
+       {
+               .procname       = "perf_event_max_contexts_per_stack",
+               .data           = &sysctl_perf_event_max_contexts_per_stack,
+               .maxlen         = sizeof(sysctl_perf_event_max_contexts_per_stack),
+               .mode           = 0644,
+               .proc_handler   = perf_event_max_stack_handler,
+               .extra1         = SYSCTL_ZERO,
+               .extra2         = SYSCTL_ONE_THOUSAND,
+       },
+};
+
+static int __init init_callchain_sysctls(void)
+{
+       register_sysctl_init("kernel", callchain_sysctl_table);
+       return 0;
+}
+core_initcall(init_callchain_sysctls);
+

diff --git a/kernel/events/core.c b/kernel/events/core.c
index 0f8c5599078305b098a7d9ba5445ff1de62d444d..45ad0f60834988bfcc2ddc5abc29cf46d58be33f 100644 (file)
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -452,8 +452,8 @@ static struct kmem_cache *perf_event_cache;
  */
 int sysctl_perf_event_paranoid __read_mostly = 2;
 
-/* Minimum for 512 kiB + 1 user control page */
-int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */
+/* Minimum for 512 kiB + 1 user control page. 'free' kiB per user. */
+static int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024);
 
 /*
  * max perf event sample rate
@@ -463,6 +463,7 @@ int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free'
 #define DEFAULT_CPU_TIME_MAX_PERCENT   25
 
 int sysctl_perf_event_sample_rate __read_mostly        = DEFAULT_MAX_SAMPLE_RATE;
+static int sysctl_perf_cpu_time_max_percent __read_mostly = DEFAULT_CPU_TIME_MAX_PERCENT;
 
 static int max_samples_per_tick __read_mostly  = DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE, HZ);
 static int perf_sample_period_ns __read_mostly = DEFAULT_SAMPLE_PERIOD_NS;
@@ -484,7 +485,7 @@ static void update_perf_cpu_limits(void)
 
 static bool perf_rotate_context(struct perf_cpu_pmu_context *cpc);
 
-int perf_event_max_sample_rate_handler(const struct ctl_table *table, int write,
+static int perf_event_max_sample_rate_handler(const struct ctl_table *table, int write,
                                       void *buffer, size_t *lenp, loff_t *ppos)
 {
        int ret;
@@ -506,9 +507,7 @@ int perf_event_max_sample_rate_handler(const struct ctl_table *table, int write,
        return 0;
 }
 
-int sysctl_perf_cpu_time_max_percent __read_mostly = DEFAULT_CPU_TIME_MAX_PERCENT;
-
-int perf_cpu_time_max_percent_handler(const struct ctl_table *table, int write,
+static int perf_cpu_time_max_percent_handler(const struct ctl_table *table, int write,
                void *buffer, size_t *lenp, loff_t *ppos)
 {
        int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
@@ -528,6 +527,52 @@ int perf_cpu_time_max_percent_handler(const struct ctl_table *table, int write,
        return 0;
 }
 
+static const struct ctl_table events_core_sysctl_table[] = {
+       /*
+        * User-space relies on this file as a feature check for
+        * perf_events being enabled. It's an ABI, do not remove!
+        */
+       {
+               .procname       = "perf_event_paranoid",
+               .data           = &sysctl_perf_event_paranoid,
+               .maxlen         = sizeof(sysctl_perf_event_paranoid),
+               .mode           = 0644,
+               .proc_handler   = proc_dointvec,
+       },
+       {
+               .procname       = "perf_event_mlock_kb",
+               .data           = &sysctl_perf_event_mlock,
+               .maxlen         = sizeof(sysctl_perf_event_mlock),
+               .mode           = 0644,
+               .proc_handler   = proc_dointvec,
+       },
+       {
+               .procname       = "perf_event_max_sample_rate",
+               .data           = &sysctl_perf_event_sample_rate,
+               .maxlen         = sizeof(sysctl_perf_event_sample_rate),
+               .mode           = 0644,
+               .proc_handler   = perf_event_max_sample_rate_handler,
+               .extra1         = SYSCTL_ONE,
+       },
+       {
+               .procname       = "perf_cpu_time_max_percent",
+               .data           = &sysctl_perf_cpu_time_max_percent,
+               .maxlen         = sizeof(sysctl_perf_cpu_time_max_percent),
+               .mode           = 0644,
+               .proc_handler   = perf_cpu_time_max_percent_handler,
+               .extra1         = SYSCTL_ZERO,
+               .extra2         = SYSCTL_ONE_HUNDRED,
+       },
+};
+
+static int __init init_events_core_sysctls(void)
+{
+       register_sysctl_init("kernel", events_core_sysctl_table);
+       return 0;
+}
+core_initcall(init_events_core_sysctls);
+
+
 /*
  * perf samples are done in some very critical code paths (NMIs).
  * If they take too much CPU time, the system can lock up and not

diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index cb57da499ebb1216cefb3705694ab62028fee03e..4484cdb504c7817eec00a9ac1ce5b698d56c29cb 100644 (file)
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -54,7 +54,6 @@
 #include <linux/acpi.h>
 #include <linux/reboot.h>
 #include <linux/ftrace.h>
-#include <linux/perf_event.h>
 #include <linux/oom.h>
 #include <linux/kmod.h>
 #include <linux/capability.h>
@@ -91,12 +90,6 @@ EXPORT_SYMBOL_GPL(sysctl_long_vals);
 #if defined(CONFIG_SYSCTL)
 
 /* Constants used for minimum and maximum */
-
-#ifdef CONFIG_PERF_EVENTS
-static const int six_hundred_forty_kb = 640 * 1024;
-#endif
-
-
 static const int ngroups_max = NGROUPS_MAX;
 static const int cap_last_cap = CAP_LAST_CAP;
 
@@ -1932,63 +1925,6 @@ static const struct ctl_table kern_table[] = {
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
-#endif
-#ifdef CONFIG_PERF_EVENTS
-       /*
-        * User-space scripts rely on the existence of this file
-        * as a feature check for perf_events being enabled.
-        *
-        * So it's an ABI, do not remove!
-        */
-       {
-               .procname       = "perf_event_paranoid",
-               .data           = &sysctl_perf_event_paranoid,
-               .maxlen         = sizeof(sysctl_perf_event_paranoid),
-               .mode           = 0644,
-               .proc_handler   = proc_dointvec,
-       },
-       {
-               .procname       = "perf_event_mlock_kb",
-               .data           = &sysctl_perf_event_mlock,
-               .maxlen         = sizeof(sysctl_perf_event_mlock),
-               .mode           = 0644,
-               .proc_handler   = proc_dointvec,
-       },
-       {
-               .procname       = "perf_event_max_sample_rate",
-               .data           = &sysctl_perf_event_sample_rate,
-               .maxlen         = sizeof(sysctl_perf_event_sample_rate),
-               .mode           = 0644,
-               .proc_handler   = perf_event_max_sample_rate_handler,
-               .extra1         = SYSCTL_ONE,
-       },
-       {
-               .procname       = "perf_cpu_time_max_percent",
-               .data           = &sysctl_perf_cpu_time_max_percent,
-               .maxlen         = sizeof(sysctl_perf_cpu_time_max_percent),
-               .mode           = 0644,
-               .proc_handler   = perf_cpu_time_max_percent_handler,
-               .extra1         = SYSCTL_ZERO,
-               .extra2         = SYSCTL_ONE_HUNDRED,
-       },
-       {
-               .procname       = "perf_event_max_stack",
-               .data           = &sysctl_perf_event_max_stack,
-               .maxlen         = sizeof(sysctl_perf_event_max_stack),
-               .mode           = 0644,
-               .proc_handler   = perf_event_max_stack_handler,
-               .extra1         = SYSCTL_ZERO,
-               .extra2         = (void *)&six_hundred_forty_kb,
-       },
-       {
-               .procname       = "perf_event_max_contexts_per_stack",
-               .data           = &sysctl_perf_event_max_contexts_per_stack,
-               .maxlen         = sizeof(sysctl_perf_event_max_contexts_per_stack),
-               .mode           = 0644,
-               .proc_handler   = perf_event_max_stack_handler,
-               .extra1         = SYSCTL_ZERO,
-               .extra2         = SYSCTL_ONE_THOUSAND,
-       },
 #endif
        {
                .procname       = "panic_on_warn",