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Message-Id: <20250218-jag-mv_ctltables-v1-5-cd3698ab8d29@kernel.org>
Date: Tue, 18 Feb 2025 10:56:21 +0100
From: Joel Granados <joel.granados@...nel.org>
To: Kees Cook <kees@...nel.org>, Steven Rostedt <rostedt@...dmis.org>,
Masami Hiramatsu <mhiramat@...nel.org>, Mark Rutland <mark.rutland@....com>,
Mathieu Desnoyers <mathieu.desnoyers@...icios.com>,
Peter Zijlstra <peterz@...radead.org>, Ingo Molnar <mingo@...hat.com>,
Arnaldo Carvalho de Melo <acme@...nel.org>,
Namhyung Kim <namhyung@...nel.org>,
Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
Jiri Olsa <jolsa@...nel.org>, Ian Rogers <irogers@...gle.com>,
Adrian Hunter <adrian.hunter@...el.com>,
"Liang, Kan" <kan.liang@...ux.intel.com>,
"David S. Miller" <davem@...emloft.net>,
Andreas Larsson <andreas@...sler.com>, Heiko Carstens <hca@...ux.ibm.com>,
Vasily Gorbik <gor@...ux.ibm.com>,
Alexander Gordeev <agordeev@...ux.ibm.com>,
Christian Borntraeger <borntraeger@...ux.ibm.com>,
Sven Schnelle <svens@...ux.ibm.com>,
Gerald Schaefer <gerald.schaefer@...ux.ibm.com>,
Thomas Gleixner <tglx@...utronix.de>, Borislav Petkov <bp@...en8.de>,
Dave Hansen <dave.hansen@...ux.intel.com>, x86@...nel.org,
"H. Peter Anvin" <hpa@...or.com>, "Rafael J. Wysocki" <rafael@...nel.org>,
Len Brown <lenb@...nel.org>
Cc: linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org,
linux-trace-kernel@...r.kernel.org, linux-perf-users@...r.kernel.org,
sparclinux@...r.kernel.org, linux-s390@...r.kernel.org,
linux-acpi@...r.kernel.org, Joel Granados <joel.granados@...nel.org>
Subject: [PATCH 5/8] events: 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@...nel.org>
---
include/linux/perf_event.h | 9 -------
kernel/events/callchain.c | 38 ++++++++++++++++++++++-----
kernel/events/core.c | 57 ++++++++++++++++++++++++++++++++++++-----
kernel/sysctl.c | 64 ----------------------------------------------
4 files changed, 83 insertions(+), 85 deletions(-)
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 8333f132f4a9..a92ade5d62be 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -1646,19 +1646,10 @@ 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 8a47e52a454f..6c83ad674d01 100644
--- 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 @@ get_perf_callchain(struct pt_regs *regs, u32 init_nr, bool kernel, bool user,
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 bcb09e011e9e..3c3d95312c28 100644
--- 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 dc3747cc72d4..fdc92d80e841 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -51,7 +51,6 @@
#include <linux/nfs_fs.h>
#include <linux/acpi.h>
#include <linux/reboot.h>
-#include <linux/perf_event.h>
#include <linux/oom.h>
#include <linux/kmod.h>
#include <linux/capability.h>
@@ -87,12 +86,6 @@ 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;
@@ -1869,63 +1862,6 @@ static const struct ctl_table kern_table[] = {
.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
#ifdef CONFIG_TREE_RCU
{
.procname = "panic_on_rcu_stall",
--
2.44.2
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