time: Remove CONFIG_TIMER_STATS
Currently CONFIG_TIMER_STATS exposes process information across namespaces:
kernel/time/timer_list.c print_timer():
SEQ_printf(m, ", %s/%d", tmp, timer->start_pid);
/proc/timer_list:
#11: <0000000000000000>, hrtimer_wakeup, S:01, do_nanosleep, cron/2570
Given that the tracer can give the same information, this patch entirely
removes CONFIG_TIMER_STATS.
Change-Id: Ice26d74094d3ad563808342c1604ad444234844b
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: John Stultz <john.stultz@linaro.org>
Cc: Nicolas Pitre <nicolas.pitre@linaro.org>
Cc: linux-doc@vger.kernel.org
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Xing Gao <xgao01@email.wm.edu>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Jessica Frazelle <me@jessfraz.com>
Cc: kernel-hardening@lists.openwall.com
Cc: Nicolas Iooss <nicolas.iooss_linux@m4x.org>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Michal Marek <mmarek@suse.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Olof Johansson <olof@lixom.net>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-api@vger.kernel.org
Cc: Arjan van de Ven <arjan@linux.intel.com>
Link: http://lkml.kernel.org/r/20170208192659.GA32582@beast
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Kees Cook
LuK1337
parent
88926b1a02
commit
9232b43518
|
|
@ -1,73 +0,0 @@
|
|||
timer_stats - timer usage statistics
|
||||
------------------------------------
|
||||
|
||||
timer_stats is a debugging facility to make the timer (ab)usage in a Linux
|
||||
system visible to kernel and userspace developers. If enabled in the config
|
||||
but not used it has almost zero runtime overhead, and a relatively small
|
||||
data structure overhead. Even if collection is enabled runtime all the
|
||||
locking is per-CPU and lookup is hashed.
|
||||
|
||||
timer_stats should be used by kernel and userspace developers to verify that
|
||||
their code does not make unduly use of timers. This helps to avoid unnecessary
|
||||
wakeups, which should be avoided to optimize power consumption.
|
||||
|
||||
It can be enabled by CONFIG_TIMER_STATS in the "Kernel hacking" configuration
|
||||
section.
|
||||
|
||||
timer_stats collects information about the timer events which are fired in a
|
||||
Linux system over a sample period:
|
||||
|
||||
- the pid of the task(process) which initialized the timer
|
||||
- the name of the process which initialized the timer
|
||||
- the function where the timer was initialized
|
||||
- the callback function which is associated to the timer
|
||||
- the number of events (callbacks)
|
||||
|
||||
timer_stats adds an entry to /proc: /proc/timer_stats
|
||||
|
||||
This entry is used to control the statistics functionality and to read out the
|
||||
sampled information.
|
||||
|
||||
The timer_stats functionality is inactive on bootup.
|
||||
|
||||
To activate a sample period issue:
|
||||
# echo 1 >/proc/timer_stats
|
||||
|
||||
To stop a sample period issue:
|
||||
# echo 0 >/proc/timer_stats
|
||||
|
||||
The statistics can be retrieved by:
|
||||
# cat /proc/timer_stats
|
||||
|
||||
The readout of /proc/timer_stats automatically disables sampling. The sampled
|
||||
information is kept until a new sample period is started. This allows multiple
|
||||
readouts.
|
||||
|
||||
Sample output of /proc/timer_stats:
|
||||
|
||||
Timerstats sample period: 3.888770 s
|
||||
12, 0 swapper hrtimer_stop_sched_tick (hrtimer_sched_tick)
|
||||
15, 1 swapper hcd_submit_urb (rh_timer_func)
|
||||
4, 959 kedac schedule_timeout (process_timeout)
|
||||
1, 0 swapper page_writeback_init (wb_timer_fn)
|
||||
28, 0 swapper hrtimer_stop_sched_tick (hrtimer_sched_tick)
|
||||
22, 2948 IRQ 4 tty_flip_buffer_push (delayed_work_timer_fn)
|
||||
3, 3100 bash schedule_timeout (process_timeout)
|
||||
1, 1 swapper queue_delayed_work_on (delayed_work_timer_fn)
|
||||
1, 1 swapper queue_delayed_work_on (delayed_work_timer_fn)
|
||||
1, 1 swapper neigh_table_init_no_netlink (neigh_periodic_timer)
|
||||
1, 2292 ip __netdev_watchdog_up (dev_watchdog)
|
||||
1, 23 events/1 do_cache_clean (delayed_work_timer_fn)
|
||||
90 total events, 30.0 events/sec
|
||||
|
||||
The first column is the number of events, the second column the pid, the third
|
||||
column is the name of the process. The forth column shows the function which
|
||||
initialized the timer and in parenthesis the callback function which was
|
||||
executed on expiry.
|
||||
|
||||
Thomas, Ingo
|
||||
|
||||
Added flag to indicate 'deferrable timer' in /proc/timer_stats. A deferrable
|
||||
timer will appear as follows
|
||||
10D, 1 swapper queue_delayed_work_on (delayed_work_timer_fn)
|
||||
|
||||
|
|
@ -96,12 +96,6 @@ enum hrtimer_restart {
|
|||
* @function: timer expiry callback function
|
||||
* @base: pointer to the timer base (per cpu and per clock)
|
||||
* @state: state information (See bit values above)
|
||||
* @start_site: timer statistics field to store the site where the timer
|
||||
* was started
|
||||
* @start_comm: timer statistics field to store the name of the process which
|
||||
* started the timer
|
||||
* @start_pid: timer statistics field to store the pid of the task which
|
||||
* started the timer
|
||||
*
|
||||
* The hrtimer structure must be initialized by hrtimer_init()
|
||||
*/
|
||||
|
|
@ -111,11 +105,6 @@ struct hrtimer {
|
|||
enum hrtimer_restart (*function)(struct hrtimer *);
|
||||
struct hrtimer_clock_base *base;
|
||||
unsigned long state;
|
||||
#ifdef CONFIG_TIMER_STATS
|
||||
int start_pid;
|
||||
void *start_site;
|
||||
char start_comm[16];
|
||||
#endif
|
||||
};
|
||||
|
||||
/**
|
||||
|
|
|
|||
|
|
@ -23,11 +23,6 @@ struct timer_list {
|
|||
|
||||
int slack;
|
||||
|
||||
#ifdef CONFIG_TIMER_STATS
|
||||
int start_pid;
|
||||
void *start_site;
|
||||
char start_comm[16];
|
||||
#endif
|
||||
#ifdef CONFIG_LOCKDEP
|
||||
struct lockdep_map lockdep_map;
|
||||
#endif
|
||||
|
|
@ -194,49 +189,6 @@ extern void set_timer_slack(struct timer_list *time, int slack_hz);
|
|||
*/
|
||||
extern unsigned long get_next_timer_interrupt(unsigned long now);
|
||||
|
||||
/*
|
||||
* Timer-statistics info:
|
||||
*/
|
||||
#ifdef CONFIG_TIMER_STATS
|
||||
|
||||
extern int timer_stats_active;
|
||||
|
||||
#define TIMER_STATS_FLAG_DEFERRABLE 0x1
|
||||
|
||||
extern void init_timer_stats(void);
|
||||
|
||||
extern void timer_stats_update_stats(void *timer, pid_t pid, void *startf,
|
||||
void *timerf, char *comm,
|
||||
unsigned int timer_flag);
|
||||
|
||||
extern void __timer_stats_timer_set_start_info(struct timer_list *timer,
|
||||
void *addr);
|
||||
|
||||
static inline void timer_stats_timer_set_start_info(struct timer_list *timer)
|
||||
{
|
||||
if (likely(!timer_stats_active))
|
||||
return;
|
||||
__timer_stats_timer_set_start_info(timer, __builtin_return_address(0));
|
||||
}
|
||||
|
||||
static inline void timer_stats_timer_clear_start_info(struct timer_list *timer)
|
||||
{
|
||||
timer->start_site = NULL;
|
||||
}
|
||||
#else
|
||||
static inline void init_timer_stats(void)
|
||||
{
|
||||
}
|
||||
|
||||
static inline void timer_stats_timer_set_start_info(struct timer_list *timer)
|
||||
{
|
||||
}
|
||||
|
||||
static inline void timer_stats_timer_clear_start_info(struct timer_list *timer)
|
||||
{
|
||||
}
|
||||
#endif
|
||||
|
||||
extern void add_timer(struct timer_list *timer);
|
||||
|
||||
extern int try_to_del_timer_sync(struct timer_list *timer);
|
||||
|
|
|
|||
|
|
@ -831,34 +831,6 @@ void hrtimers_resume(void)
|
|||
clock_was_set_delayed();
|
||||
}
|
||||
|
||||
static inline void timer_stats_hrtimer_set_start_info(struct hrtimer *timer)
|
||||
{
|
||||
#ifdef CONFIG_TIMER_STATS
|
||||
if (timer->start_site)
|
||||
return;
|
||||
timer->start_site = __builtin_return_address(0);
|
||||
memcpy(timer->start_comm, current->comm, TASK_COMM_LEN);
|
||||
timer->start_pid = current->pid;
|
||||
#endif
|
||||
}
|
||||
|
||||
static inline void timer_stats_hrtimer_clear_start_info(struct hrtimer *timer)
|
||||
{
|
||||
#ifdef CONFIG_TIMER_STATS
|
||||
timer->start_site = NULL;
|
||||
#endif
|
||||
}
|
||||
|
||||
static inline void timer_stats_account_hrtimer(struct hrtimer *timer)
|
||||
{
|
||||
#ifdef CONFIG_TIMER_STATS
|
||||
if (likely(!timer_stats_active))
|
||||
return;
|
||||
timer_stats_update_stats(timer, timer->start_pid, timer->start_site,
|
||||
timer->function, timer->start_comm, 0);
|
||||
#endif
|
||||
}
|
||||
|
||||
/*
|
||||
* Counterpart to lock_hrtimer_base above:
|
||||
*/
|
||||
|
|
@ -992,7 +964,6 @@ remove_hrtimer(struct hrtimer *timer, struct hrtimer_clock_base *base)
|
|||
* rare case and less expensive than a smp call.
|
||||
*/
|
||||
debug_deactivate(timer);
|
||||
timer_stats_hrtimer_clear_start_info(timer);
|
||||
reprogram = base->cpu_base == &__get_cpu_var(hrtimer_bases);
|
||||
/*
|
||||
* We must preserve the CALLBACK state flag here,
|
||||
|
|
@ -1038,8 +1009,6 @@ int __hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
|
|||
/* Switch the timer base, if necessary: */
|
||||
new_base = switch_hrtimer_base(timer, base, mode & HRTIMER_MODE_PINNED);
|
||||
|
||||
timer_stats_hrtimer_set_start_info(timer);
|
||||
|
||||
leftmost = enqueue_hrtimer(timer, new_base);
|
||||
|
||||
/*
|
||||
|
|
@ -1215,12 +1184,6 @@ static void __hrtimer_init(struct hrtimer *timer, clockid_t clock_id,
|
|||
base = hrtimer_clockid_to_base(clock_id);
|
||||
timer->base = &cpu_base->clock_base[base];
|
||||
timerqueue_init(&timer->node);
|
||||
|
||||
#ifdef CONFIG_TIMER_STATS
|
||||
timer->start_site = NULL;
|
||||
timer->start_pid = -1;
|
||||
memset(timer->start_comm, 0, TASK_COMM_LEN);
|
||||
#endif
|
||||
}
|
||||
|
||||
/**
|
||||
|
|
@ -1268,7 +1231,6 @@ static void __run_hrtimer(struct hrtimer *timer, ktime_t *now)
|
|||
|
||||
debug_deactivate(timer);
|
||||
__remove_hrtimer(timer, base, HRTIMER_STATE_CALLBACK, 0);
|
||||
timer_stats_account_hrtimer(timer);
|
||||
fn = timer->function;
|
||||
|
||||
/*
|
||||
|
|
|
|||
|
|
@ -7,6 +7,5 @@ obj-$(CONFIG_GENERIC_CLOCKEVENTS_BROADCAST) += tick-broadcast.o tick-broadcast-h
|
|||
obj-$(CONFIG_GENERIC_SCHED_CLOCK) += sched_clock.o
|
||||
obj-$(CONFIG_TICK_ONESHOT) += tick-oneshot.o
|
||||
obj-$(CONFIG_TICK_ONESHOT) += tick-sched.o
|
||||
obj-$(CONFIG_TIMER_STATS) += timer_stats.o
|
||||
|
||||
ccflags-y += -Idrivers/cpuidle
|
||||
|
|
|
|||
|
|
@ -57,21 +57,11 @@ static void
|
|||
print_timer(struct seq_file *m, struct hrtimer *taddr, struct hrtimer *timer,
|
||||
int idx, u64 now)
|
||||
{
|
||||
#ifdef CONFIG_TIMER_STATS
|
||||
char tmp[TASK_COMM_LEN + 1];
|
||||
#endif
|
||||
SEQ_printf(m, " #%d: ", idx);
|
||||
print_name_offset(m, taddr);
|
||||
SEQ_printf(m, ", ");
|
||||
print_name_offset(m, timer->function);
|
||||
SEQ_printf(m, ", S:%02lx", timer->state);
|
||||
#ifdef CONFIG_TIMER_STATS
|
||||
SEQ_printf(m, ", ");
|
||||
print_name_offset(m, timer->start_site);
|
||||
memcpy(tmp, timer->start_comm, TASK_COMM_LEN);
|
||||
tmp[TASK_COMM_LEN] = 0;
|
||||
SEQ_printf(m, ", %s/%d", tmp, timer->start_pid);
|
||||
#endif
|
||||
SEQ_printf(m, "\n");
|
||||
SEQ_printf(m, " # expires at %Lu-%Lu nsecs [in %Ld to %Ld nsecs]\n",
|
||||
(unsigned long long)ktime_to_ns(hrtimer_get_softexpires(timer)),
|
||||
|
|
|
|||
|
|
@ -1,425 +0,0 @@
|
|||
/*
|
||||
* kernel/time/timer_stats.c
|
||||
*
|
||||
* Collect timer usage statistics.
|
||||
*
|
||||
* Copyright(C) 2006, Red Hat, Inc., Ingo Molnar
|
||||
* Copyright(C) 2006 Timesys Corp., Thomas Gleixner <tglx@timesys.com>
|
||||
*
|
||||
* timer_stats is based on timer_top, a similar functionality which was part of
|
||||
* Con Kolivas dyntick patch set. It was developed by Daniel Petrini at the
|
||||
* Instituto Nokia de Tecnologia - INdT - Manaus. timer_top's design was based
|
||||
* on dynamic allocation of the statistics entries and linear search based
|
||||
* lookup combined with a global lock, rather than the static array, hash
|
||||
* and per-CPU locking which is used by timer_stats. It was written for the
|
||||
* pre hrtimer kernel code and therefore did not take hrtimers into account.
|
||||
* Nevertheless it provided the base for the timer_stats implementation and
|
||||
* was a helpful source of inspiration. Kudos to Daniel and the Nokia folks
|
||||
* for this effort.
|
||||
*
|
||||
* timer_top.c is
|
||||
* Copyright (C) 2005 Instituto Nokia de Tecnologia - INdT - Manaus
|
||||
* Written by Daniel Petrini <d.pensator@gmail.com>
|
||||
* timer_top.c was released under the GNU General Public License version 2
|
||||
*
|
||||
* We export the addresses and counting of timer functions being called,
|
||||
* the pid and cmdline from the owner process if applicable.
|
||||
*
|
||||
* Start/stop data collection:
|
||||
* # echo [1|0] >/proc/timer_stats
|
||||
*
|
||||
* Display the information collected so far:
|
||||
* # cat /proc/timer_stats
|
||||
*
|
||||
* This program is free software; you can redistribute it and/or modify
|
||||
* it under the terms of the GNU General Public License version 2 as
|
||||
* published by the Free Software Foundation.
|
||||
*/
|
||||
|
||||
#include <linux/proc_fs.h>
|
||||
#include <linux/module.h>
|
||||
#include <linux/spinlock.h>
|
||||
#include <linux/sched.h>
|
||||
#include <linux/seq_file.h>
|
||||
#include <linux/kallsyms.h>
|
||||
|
||||
#include <asm/uaccess.h>
|
||||
|
||||
/*
|
||||
* This is our basic unit of interest: a timer expiry event identified
|
||||
* by the timer, its start/expire functions and the PID of the task that
|
||||
* started the timer. We count the number of times an event happens:
|
||||
*/
|
||||
struct entry {
|
||||
/*
|
||||
* Hash list:
|
||||
*/
|
||||
struct entry *next;
|
||||
|
||||
/*
|
||||
* Hash keys:
|
||||
*/
|
||||
void *timer;
|
||||
void *start_func;
|
||||
void *expire_func;
|
||||
pid_t pid;
|
||||
|
||||
/*
|
||||
* Number of timeout events:
|
||||
*/
|
||||
unsigned long count;
|
||||
unsigned int timer_flag;
|
||||
|
||||
/*
|
||||
* We save the command-line string to preserve
|
||||
* this information past task exit:
|
||||
*/
|
||||
char comm[TASK_COMM_LEN + 1];
|
||||
|
||||
} ____cacheline_aligned_in_smp;
|
||||
|
||||
/*
|
||||
* Spinlock protecting the tables - not taken during lookup:
|
||||
*/
|
||||
static DEFINE_RAW_SPINLOCK(table_lock);
|
||||
|
||||
/*
|
||||
* Per-CPU lookup locks for fast hash lookup:
|
||||
*/
|
||||
static DEFINE_PER_CPU(raw_spinlock_t, tstats_lookup_lock);
|
||||
|
||||
/*
|
||||
* Mutex to serialize state changes with show-stats activities:
|
||||
*/
|
||||
static DEFINE_MUTEX(show_mutex);
|
||||
|
||||
/*
|
||||
* Collection status, active/inactive:
|
||||
*/
|
||||
int __read_mostly timer_stats_active;
|
||||
|
||||
/*
|
||||
* Beginning/end timestamps of measurement:
|
||||
*/
|
||||
static ktime_t time_start, time_stop;
|
||||
|
||||
/*
|
||||
* tstat entry structs only get allocated while collection is
|
||||
* active and never freed during that time - this simplifies
|
||||
* things quite a bit.
|
||||
*
|
||||
* They get freed when a new collection period is started.
|
||||
*/
|
||||
#define MAX_ENTRIES_BITS 10
|
||||
#define MAX_ENTRIES (1UL << MAX_ENTRIES_BITS)
|
||||
|
||||
static unsigned long nr_entries;
|
||||
static struct entry entries[MAX_ENTRIES];
|
||||
|
||||
static atomic_t overflow_count;
|
||||
|
||||
/*
|
||||
* The entries are in a hash-table, for fast lookup:
|
||||
*/
|
||||
#define TSTAT_HASH_BITS (MAX_ENTRIES_BITS - 1)
|
||||
#define TSTAT_HASH_SIZE (1UL << TSTAT_HASH_BITS)
|
||||
#define TSTAT_HASH_MASK (TSTAT_HASH_SIZE - 1)
|
||||
|
||||
#define __tstat_hashfn(entry) \
|
||||
(((unsigned long)(entry)->timer ^ \
|
||||
(unsigned long)(entry)->start_func ^ \
|
||||
(unsigned long)(entry)->expire_func ^ \
|
||||
(unsigned long)(entry)->pid ) & TSTAT_HASH_MASK)
|
||||
|
||||
#define tstat_hashentry(entry) (tstat_hash_table + __tstat_hashfn(entry))
|
||||
|
||||
static struct entry *tstat_hash_table[TSTAT_HASH_SIZE] __read_mostly;
|
||||
|
||||
static void reset_entries(void)
|
||||
{
|
||||
nr_entries = 0;
|
||||
memset(entries, 0, sizeof(entries));
|
||||
memset(tstat_hash_table, 0, sizeof(tstat_hash_table));
|
||||
atomic_set(&overflow_count, 0);
|
||||
}
|
||||
|
||||
static struct entry *alloc_entry(void)
|
||||
{
|
||||
if (nr_entries >= MAX_ENTRIES)
|
||||
return NULL;
|
||||
|
||||
return entries + nr_entries++;
|
||||
}
|
||||
|
||||
static int match_entries(struct entry *entry1, struct entry *entry2)
|
||||
{
|
||||
return entry1->timer == entry2->timer &&
|
||||
entry1->start_func == entry2->start_func &&
|
||||
entry1->expire_func == entry2->expire_func &&
|
||||
entry1->pid == entry2->pid;
|
||||
}
|
||||
|
||||
/*
|
||||
* Look up whether an entry matching this item is present
|
||||
* in the hash already. Must be called with irqs off and the
|
||||
* lookup lock held:
|
||||
*/
|
||||
static struct entry *tstat_lookup(struct entry *entry, char *comm)
|
||||
{
|
||||
struct entry **head, *curr, *prev;
|
||||
|
||||
head = tstat_hashentry(entry);
|
||||
curr = *head;
|
||||
|
||||
/*
|
||||
* The fastpath is when the entry is already hashed,
|
||||
* we do this with the lookup lock held, but with the
|
||||
* table lock not held:
|
||||
*/
|
||||
while (curr) {
|
||||
if (match_entries(curr, entry))
|
||||
return curr;
|
||||
|
||||
curr = curr->next;
|
||||
}
|
||||
/*
|
||||
* Slowpath: allocate, set up and link a new hash entry:
|
||||
*/
|
||||
prev = NULL;
|
||||
curr = *head;
|
||||
|
||||
raw_spin_lock(&table_lock);
|
||||
/*
|
||||
* Make sure we have not raced with another CPU:
|
||||
*/
|
||||
while (curr) {
|
||||
if (match_entries(curr, entry))
|
||||
goto out_unlock;
|
||||
|
||||
prev = curr;
|
||||
curr = curr->next;
|
||||
}
|
||||
|
||||
curr = alloc_entry();
|
||||
if (curr) {
|
||||
*curr = *entry;
|
||||
curr->count = 0;
|
||||
curr->next = NULL;
|
||||
memcpy(curr->comm, comm, TASK_COMM_LEN);
|
||||
|
||||
smp_mb(); /* Ensure that curr is initialized before insert */
|
||||
|
||||
if (prev)
|
||||
prev->next = curr;
|
||||
else
|
||||
*head = curr;
|
||||
}
|
||||
out_unlock:
|
||||
raw_spin_unlock(&table_lock);
|
||||
|
||||
return curr;
|
||||
}
|
||||
|
||||
/**
|
||||
* timer_stats_update_stats - Update the statistics for a timer.
|
||||
* @timer: pointer to either a timer_list or a hrtimer
|
||||
* @pid: the pid of the task which set up the timer
|
||||
* @startf: pointer to the function which did the timer setup
|
||||
* @timerf: pointer to the timer callback function of the timer
|
||||
* @comm: name of the process which set up the timer
|
||||
*
|
||||
* When the timer is already registered, then the event counter is
|
||||
* incremented. Otherwise the timer is registered in a free slot.
|
||||
*/
|
||||
void timer_stats_update_stats(void *timer, pid_t pid, void *startf,
|
||||
void *timerf, char *comm,
|
||||
unsigned int timer_flag)
|
||||
{
|
||||
/*
|
||||
* It doesn't matter which lock we take:
|
||||
*/
|
||||
raw_spinlock_t *lock;
|
||||
struct entry *entry, input;
|
||||
unsigned long flags;
|
||||
|
||||
if (likely(!timer_stats_active))
|
||||
return;
|
||||
|
||||
lock = &per_cpu(tstats_lookup_lock, raw_smp_processor_id());
|
||||
|
||||
input.timer = timer;
|
||||
input.start_func = startf;
|
||||
input.expire_func = timerf;
|
||||
input.pid = pid;
|
||||
input.timer_flag = timer_flag;
|
||||
|
||||
raw_spin_lock_irqsave(lock, flags);
|
||||
if (!timer_stats_active)
|
||||
goto out_unlock;
|
||||
|
||||
entry = tstat_lookup(&input, comm);
|
||||
if (likely(entry))
|
||||
entry->count++;
|
||||
else
|
||||
atomic_inc(&overflow_count);
|
||||
|
||||
out_unlock:
|
||||
raw_spin_unlock_irqrestore(lock, flags);
|
||||
}
|
||||
|
||||
static void print_name_offset(struct seq_file *m, unsigned long addr)
|
||||
{
|
||||
char symname[KSYM_NAME_LEN];
|
||||
|
||||
if (lookup_symbol_name(addr, symname) < 0)
|
||||
seq_printf(m, "<%p>", (void *)addr);
|
||||
else
|
||||
seq_printf(m, "%s", symname);
|
||||
}
|
||||
|
||||
static int tstats_show(struct seq_file *m, void *v)
|
||||
{
|
||||
struct timespec period;
|
||||
struct entry *entry;
|
||||
unsigned long ms;
|
||||
long events = 0;
|
||||
ktime_t time;
|
||||
int i;
|
||||
|
||||
mutex_lock(&show_mutex);
|
||||
/*
|
||||
* If still active then calculate up to now:
|
||||
*/
|
||||
if (timer_stats_active)
|
||||
time_stop = ktime_get();
|
||||
|
||||
time = ktime_sub(time_stop, time_start);
|
||||
|
||||
period = ktime_to_timespec(time);
|
||||
ms = period.tv_nsec / 1000000;
|
||||
|
||||
seq_puts(m, "Timer Stats Version: v0.2\n");
|
||||
seq_printf(m, "Sample period: %ld.%03ld s\n", period.tv_sec, ms);
|
||||
if (atomic_read(&overflow_count))
|
||||
seq_printf(m, "Overflow: %d entries\n",
|
||||
atomic_read(&overflow_count));
|
||||
|
||||
for (i = 0; i < nr_entries; i++) {
|
||||
entry = entries + i;
|
||||
if (entry->timer_flag & TIMER_STATS_FLAG_DEFERRABLE) {
|
||||
seq_printf(m, "%4luD, %5d %-16s ",
|
||||
entry->count, entry->pid, entry->comm);
|
||||
} else {
|
||||
seq_printf(m, " %4lu, %5d %-16s ",
|
||||
entry->count, entry->pid, entry->comm);
|
||||
}
|
||||
|
||||
print_name_offset(m, (unsigned long)entry->start_func);
|
||||
seq_puts(m, " (");
|
||||
print_name_offset(m, (unsigned long)entry->expire_func);
|
||||
seq_puts(m, ")\n");
|
||||
|
||||
events += entry->count;
|
||||
}
|
||||
|
||||
ms += period.tv_sec * 1000;
|
||||
if (!ms)
|
||||
ms = 1;
|
||||
|
||||
if (events && period.tv_sec)
|
||||
seq_printf(m, "%ld total events, %ld.%03ld events/sec\n",
|
||||
events, events * 1000 / ms,
|
||||
(events * 1000000 / ms) % 1000);
|
||||
else
|
||||
seq_printf(m, "%ld total events\n", events);
|
||||
|
||||
mutex_unlock(&show_mutex);
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
/*
|
||||
* After a state change, make sure all concurrent lookup/update
|
||||
* activities have stopped:
|
||||
*/
|
||||
static void sync_access(void)
|
||||
{
|
||||
unsigned long flags;
|
||||
int cpu;
|
||||
|
||||
for_each_online_cpu(cpu) {
|
||||
raw_spinlock_t *lock = &per_cpu(tstats_lookup_lock, cpu);
|
||||
|
||||
raw_spin_lock_irqsave(lock, flags);
|
||||
/* nothing */
|
||||
raw_spin_unlock_irqrestore(lock, flags);
|
||||
}
|
||||
}
|
||||
|
||||
static ssize_t tstats_write(struct file *file, const char __user *buf,
|
||||
size_t count, loff_t *offs)
|
||||
{
|
||||
char ctl[2];
|
||||
|
||||
if (count != 2 || *offs)
|
||||
return -EINVAL;
|
||||
|
||||
if (copy_from_user(ctl, buf, count))
|
||||
return -EFAULT;
|
||||
|
||||
mutex_lock(&show_mutex);
|
||||
switch (ctl[0]) {
|
||||
case '0':
|
||||
if (timer_stats_active) {
|
||||
timer_stats_active = 0;
|
||||
time_stop = ktime_get();
|
||||
sync_access();
|
||||
}
|
||||
break;
|
||||
case '1':
|
||||
if (!timer_stats_active) {
|
||||
reset_entries();
|
||||
time_start = ktime_get();
|
||||
smp_mb();
|
||||
timer_stats_active = 1;
|
||||
}
|
||||
break;
|
||||
default:
|
||||
count = -EINVAL;
|
||||
}
|
||||
mutex_unlock(&show_mutex);
|
||||
|
||||
return count;
|
||||
}
|
||||
|
||||
static int tstats_open(struct inode *inode, struct file *filp)
|
||||
{
|
||||
return single_open(filp, tstats_show, NULL);
|
||||
}
|
||||
|
||||
static const struct file_operations tstats_fops = {
|
||||
.open = tstats_open,
|
||||
.read = seq_read,
|
||||
.write = tstats_write,
|
||||
.llseek = seq_lseek,
|
||||
.release = single_release,
|
||||
};
|
||||
|
||||
void __init init_timer_stats(void)
|
||||
{
|
||||
int cpu;
|
||||
|
||||
for_each_possible_cpu(cpu)
|
||||
raw_spin_lock_init(&per_cpu(tstats_lookup_lock, cpu));
|
||||
}
|
||||
|
||||
static int __init init_tstats_procfs(void)
|
||||
{
|
||||
struct proc_dir_entry *pe;
|
||||
|
||||
pe = proc_create("timer_stats", 0644, NULL, &tstats_fops);
|
||||
if (!pe)
|
||||
return -ENOMEM;
|
||||
return 0;
|
||||
}
|
||||
__initcall(init_tstats_procfs);
|
||||
|
|
@ -409,34 +409,6 @@ static int internal_add_timer(struct tvec_base *base, struct timer_list *timer)
|
|||
return leftmost;
|
||||
}
|
||||
|
||||
#ifdef CONFIG_TIMER_STATS
|
||||
void __timer_stats_timer_set_start_info(struct timer_list *timer, void *addr)
|
||||
{
|
||||
if (timer->start_site)
|
||||
return;
|
||||
|
||||
timer->start_site = addr;
|
||||
memcpy(timer->start_comm, current->comm, TASK_COMM_LEN);
|
||||
timer->start_pid = current->pid;
|
||||
}
|
||||
|
||||
static void timer_stats_account_timer(struct timer_list *timer)
|
||||
{
|
||||
unsigned int flag = 0;
|
||||
|
||||
if (likely(!timer->start_site))
|
||||
return;
|
||||
if (unlikely(tbase_get_deferrable(timer->base)))
|
||||
flag |= TIMER_STATS_FLAG_DEFERRABLE;
|
||||
|
||||
timer_stats_update_stats(timer, timer->start_pid, timer->start_site,
|
||||
timer->function, timer->start_comm, flag);
|
||||
}
|
||||
|
||||
#else
|
||||
static void timer_stats_account_timer(struct timer_list *timer) {}
|
||||
#endif
|
||||
|
||||
#ifdef CONFIG_DEBUG_OBJECTS_TIMERS
|
||||
|
||||
static struct debug_obj_descr timer_debug_descr;
|
||||
|
|
@ -649,11 +621,6 @@ static void do_init_timer(struct timer_list *timer, unsigned int flags,
|
|||
timer->entry.next = NULL;
|
||||
timer->base = (void *)((unsigned long)base | flags);
|
||||
timer->slack = -1;
|
||||
#ifdef CONFIG_TIMER_STATS
|
||||
timer->start_site = NULL;
|
||||
timer->start_pid = -1;
|
||||
memset(timer->start_comm, 0, TASK_COMM_LEN);
|
||||
#endif
|
||||
lockdep_init_map(&timer->lockdep_map, name, key, 0);
|
||||
}
|
||||
|
||||
|
|
@ -751,7 +718,6 @@ __mod_timer(struct timer_list *timer, unsigned long expires,
|
|||
unsigned long flags;
|
||||
int ret = 0, cpu, leftmost;
|
||||
|
||||
timer_stats_timer_set_start_info(timer);
|
||||
BUG_ON(!timer->function);
|
||||
|
||||
base = lock_timer_base(timer, &flags);
|
||||
|
|
@ -973,7 +939,6 @@ void add_timer_on(struct timer_list *timer, int cpu)
|
|||
unsigned long flags;
|
||||
int leftmost;
|
||||
|
||||
timer_stats_timer_set_start_info(timer);
|
||||
BUG_ON(timer_pending(timer) || !timer->function);
|
||||
spin_lock_irqsave(&base->lock, flags);
|
||||
timer_set_base(timer, base);
|
||||
|
|
@ -1013,7 +978,6 @@ int del_timer(struct timer_list *timer)
|
|||
|
||||
debug_assert_init(timer);
|
||||
|
||||
timer_stats_timer_clear_start_info(timer);
|
||||
if (timer_pending(timer)) {
|
||||
base = lock_timer_base(timer, &flags);
|
||||
ret = detach_if_pending(timer, base, true);
|
||||
|
|
@ -1041,10 +1005,9 @@ int try_to_del_timer_sync(struct timer_list *timer)
|
|||
|
||||
base = lock_timer_base(timer, &flags);
|
||||
|
||||
if (base->running_timer != timer) {
|
||||
timer_stats_timer_clear_start_info(timer);
|
||||
if (base->running_timer != timer)
|
||||
ret = detach_if_pending(timer, base, true);
|
||||
}
|
||||
|
||||
spin_unlock_irqrestore(&base->lock, flags);
|
||||
|
||||
return ret;
|
||||
|
|
@ -1229,8 +1192,6 @@ static inline void __run_timers(struct tvec_base *base)
|
|||
data = timer->data;
|
||||
irqsafe = tbase_get_irqsafe(timer->base);
|
||||
|
||||
timer_stats_account_timer(timer);
|
||||
|
||||
base->running_timer = timer;
|
||||
detach_expired_timer(timer, base);
|
||||
|
||||
|
|
@ -1728,7 +1689,6 @@ void __init init_timers(void)
|
|||
|
||||
err = timer_cpu_notify(&timers_nb, (unsigned long)CPU_UP_PREPARE,
|
||||
(void *)(long)smp_processor_id());
|
||||
init_timer_stats();
|
||||
|
||||
BUG_ON(err != NOTIFY_OK);
|
||||
|
||||
|
|
|
|||
|
|
@ -1481,8 +1481,6 @@ static void __queue_delayed_work(int cpu, struct workqueue_struct *wq,
|
|||
return;
|
||||
}
|
||||
|
||||
timer_stats_timer_set_start_info(&dwork->timer);
|
||||
|
||||
dwork->wq = wq;
|
||||
dwork->cpu = cpu;
|
||||
timer->expires = jiffies + delay;
|
||||
|
|
|
|||
|
|
@ -391,20 +391,6 @@ config SCHEDSTATS
|
|||
application, you can say N to avoid the very slight overhead
|
||||
this adds.
|
||||
|
||||
config TIMER_STATS
|
||||
bool "Collect kernel timers statistics"
|
||||
depends on DEBUG_KERNEL && PROC_FS
|
||||
help
|
||||
If you say Y here, additional code will be inserted into the
|
||||
timer routines to collect statistics about kernel timers being
|
||||
reprogrammed. The statistics can be read from /proc/timer_stats.
|
||||
The statistics collection is started by writing 1 to /proc/timer_stats,
|
||||
writing 0 stops it. This feature is useful to collect information
|
||||
about timer usage patterns in kernel and userspace. This feature
|
||||
is lightweight if enabled in the kernel config but not activated
|
||||
(it defaults to deactivated on bootup and will only be activated
|
||||
if some application like powertop activates it explicitly).
|
||||
|
||||
config DEBUG_OBJECTS
|
||||
bool "Debug object operations"
|
||||
depends on DEBUG_KERNEL
|
||||
|
|
|
|||
Loading…
Reference in New Issue