Hi,
In this version, just a few warnings fixed due to missing type updates. And also
a selftest for quick basic breakage checks.
The branch is pullable from:
git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks.git
timers/posix-cpu-timers
Thanks.
Frederic Weisbecker (4):
posix_cpu_timer: Consolidate expiry time type
posix_cpu_timers: Consolidate timer list cleanups
posix_cpu_timers: Consolidate expired timers check
selftests: Add basic posix timers selftests
include/linux/posix-timers.h | 16 +-
kernel/posix-cpu-timers.c | 390 +++++++++----------------
tools/testing/selftests/Makefile | 1 +
tools/testing/selftests/timers/Makefile | 8 +
tools/testing/selftests/timers/posix_timers.c | 221 ++++++++++++++
5 files changed, 378 insertions(+), 258 deletions(-)
create mode 100644 tools/testing/selftests/timers/Makefile
create mode 100644 tools/testing/selftests/timers/posix_timers.c
--
1.7.5.4
Consolidate the common code amongst per thread and per process
timers list on tick time.
List traversal, expiry check and subsequent updates can be
shared in a common helper.
Signed-off-by: Frederic Weisbecker <[email protected]>
Cc: Stanislaw Gruszka <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Oleg Nesterov <[email protected]>
---
kernel/posix-cpu-timers.c | 118 +++++++++++++--------------------------------
1 files changed, 33 insertions(+), 85 deletions(-)
diff --git a/kernel/posix-cpu-timers.c b/kernel/posix-cpu-timers.c
index b30775f..edf94b6 100644
--- a/kernel/posix-cpu-timers.c
+++ b/kernel/posix-cpu-timers.c
@@ -812,6 +812,28 @@ static void posix_cpu_timer_get(struct k_itimer *timer, struct itimerspec *itp)
}
}
+static unsigned long long
+check_timers_list(struct list_head *timers,
+ struct list_head *firing,
+ unsigned long long curr)
+{
+ int maxfire = 20;
+
+ while (!list_empty(timers)) {
+ struct cpu_timer_list *t;
+
+ t = list_first_entry(timers, struct cpu_timer_list, entry);
+
+ if (!--maxfire || curr < t->expires)
+ return t->expires;
+
+ t->firing = 1;
+ list_move_tail(&t->entry, firing);
+ }
+
+ return 0;
+}
+
/*
* Check for any per-thread CPU timers that have fired and move them off
* the tsk->cpu_timers[N] list onto the firing list. Here we update the
@@ -820,54 +842,20 @@ static void posix_cpu_timer_get(struct k_itimer *timer, struct itimerspec *itp)
static void check_thread_timers(struct task_struct *tsk,
struct list_head *firing)
{
- int maxfire;
struct list_head *timers = tsk->cpu_timers;
struct signal_struct *const sig = tsk->signal;
+ struct task_cputime *tsk_expires = &tsk->cputime_expires;
+ unsigned long long expires;
unsigned long soft;
- maxfire = 20;
- tsk->cputime_expires.prof_exp = 0;
- while (!list_empty(timers)) {
- struct cpu_timer_list *t = list_first_entry(timers,
- struct cpu_timer_list,
- entry);
- if (!--maxfire || prof_ticks(tsk) < t->expires) {
- tsk->cputime_expires.prof_exp = expires_to_cputime(t->expires);
- break;
- }
- t->firing = 1;
- list_move_tail(&t->entry, firing);
- }
+ expires = check_timers_list(timers, firing, prof_ticks(tsk));
+ tsk_expires->prof_exp = expires_to_cputime(expires);
- ++timers;
- maxfire = 20;
- tsk->cputime_expires.virt_exp = 0;
- while (!list_empty(timers)) {
- struct cpu_timer_list *t = list_first_entry(timers,
- struct cpu_timer_list,
- entry);
- if (!--maxfire || virt_ticks(tsk) < t->expires) {
- tsk->cputime_expires.virt_exp = expires_to_cputime(t->expires);
- break;
- }
- t->firing = 1;
- list_move_tail(&t->entry, firing);
- }
+ expires = check_timers_list(++timers, firing, virt_ticks(tsk));
+ tsk_expires->virt_exp = expires_to_cputime(expires);
- ++timers;
- maxfire = 20;
- tsk->cputime_expires.sched_exp = 0;
- while (!list_empty(timers)) {
- struct cpu_timer_list *t = list_first_entry(timers,
- struct cpu_timer_list,
- entry);
- if (!--maxfire || tsk->se.sum_exec_runtime < t->expires) {
- tsk->cputime_expires.sched_exp = t->expires;
- break;
- }
- t->firing = 1;
- list_move_tail(&t->entry, firing);
- }
+ tsk_expires->sched_exp = check_timers_list(++timers, firing,
+ tsk->se.sum_exec_runtime);
/*
* Check for the special case thread timers.
@@ -967,7 +955,6 @@ static inline int task_cputime_zero(const struct task_cputime *cputime)
static void check_process_timers(struct task_struct *tsk,
struct list_head *firing)
{
- int maxfire;
struct signal_struct *const sig = tsk->signal;
unsigned long long utime, ptime, virt_expires, prof_expires;
unsigned long long sum_sched_runtime, sched_expires;
@@ -982,49 +969,10 @@ static void check_process_timers(struct task_struct *tsk,
utime = cputime_to_expires(cputime.utime);
ptime = utime + cputime_to_expires(cputime.stime);
sum_sched_runtime = cputime.sum_exec_runtime;
- maxfire = 20;
- prof_expires = 0;
- while (!list_empty(timers)) {
- struct cpu_timer_list *tl = list_first_entry(timers,
- struct cpu_timer_list,
- entry);
- if (!--maxfire || ptime < tl->expires) {
- prof_expires = tl->expires;
- break;
- }
- tl->firing = 1;
- list_move_tail(&tl->entry, firing);
- }
- ++timers;
- maxfire = 20;
- virt_expires = 0;
- while (!list_empty(timers)) {
- struct cpu_timer_list *tl = list_first_entry(timers,
- struct cpu_timer_list,
- entry);
- if (!--maxfire || utime < tl->expires) {
- virt_expires = tl->expires;
- break;
- }
- tl->firing = 1;
- list_move_tail(&tl->entry, firing);
- }
-
- ++timers;
- maxfire = 20;
- sched_expires = 0;
- while (!list_empty(timers)) {
- struct cpu_timer_list *tl = list_first_entry(timers,
- struct cpu_timer_list,
- entry);
- if (!--maxfire || sum_sched_runtime < tl->expires) {
- sched_expires = tl->expires;
- break;
- }
- tl->firing = 1;
- list_move_tail(&tl->entry, firing);
- }
+ prof_expires = check_timers_list(timers, firing, ptime);
+ virt_expires = check_timers_list(++timers, firing, utime);
+ sched_expires = check_timers_list(++timers, firing, sum_sched_runtime);
/*
* Check for the special case process timers.
--
1.7.5.4
Add some initial basic tests on a few posix timers
interface such as setitimer() and timer_settime().
These simply check that expiration happens in a reasonable
timeframe after expected elapsed clock time (user time,
user + system time, real time, ...).
This is helpful for finding basic breakages while hacking
on this subsystem.
Signed-off-by: Frederic Weisbecker <[email protected]>
Cc: Stanislaw Gruszka <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Steven Rostedt <[email protected]>
---
tools/testing/selftests/Makefile | 1 +
tools/testing/selftests/timers/Makefile | 8 +
tools/testing/selftests/timers/posix_timers.c | 221 +++++++++++++++++++++++++
3 files changed, 230 insertions(+), 0 deletions(-)
create mode 100644 tools/testing/selftests/timers/Makefile
create mode 100644 tools/testing/selftests/timers/posix_timers.c
diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile
index 3cc0ad7..4bdaede 100644
--- a/tools/testing/selftests/Makefile
+++ b/tools/testing/selftests/Makefile
@@ -5,6 +5,7 @@ TARGETS += vm
TARGETS += cpu-hotplug
TARGETS += memory-hotplug
TARGETS += efivarfs
+TARGETS += timers
all:
for TARGET in $(TARGETS); do \
diff --git a/tools/testing/selftests/timers/Makefile b/tools/testing/selftests/timers/Makefile
new file mode 100644
index 0000000..eb2859f
--- /dev/null
+++ b/tools/testing/selftests/timers/Makefile
@@ -0,0 +1,8 @@
+all:
+ gcc posix_timers.c -o posix_timers -lrt
+
+run_tests: all
+ ./posix_timers
+
+clean:
+ rm -f ./posix_timers
diff --git a/tools/testing/selftests/timers/posix_timers.c b/tools/testing/selftests/timers/posix_timers.c
new file mode 100644
index 0000000..4fa655d
--- /dev/null
+++ b/tools/testing/selftests/timers/posix_timers.c
@@ -0,0 +1,221 @@
+/*
+ * Copyright (C) 2013 Red Hat, Inc., Frederic Weisbecker <[email protected]>
+ *
+ * Licensed under the terms of the GNU GPL License version 2
+ *
+ * Selftests for a few posix timers interface.
+ *
+ * Kernel loop code stolen from Steven Rostedt <[email protected]>
+ */
+
+#include <sys/time.h>
+#include <stdio.h>
+#include <signal.h>
+#include <unistd.h>
+#include <time.h>
+#include <pthread.h>
+
+#define DELAY 2
+#define USECS_PER_SEC 1000000
+
+static volatile int done;
+
+/* Busy loop in userspace to elapse ITIMER_VIRTUAL */
+static void user_loop(void)
+{
+ while (!done);
+}
+
+/*
+ * Try to spend as much time as possible in kernelspace
+ * to elapse ITIMER_PROF.
+ */
+static void kernel_loop(void)
+{
+ void *addr = sbrk(0);
+
+ while (!done) {
+ brk(addr + 4096);
+ brk(addr);
+ }
+}
+
+/*
+ * Sleep until ITIMER_REAL expiration.
+ */
+static void idle_loop(void)
+{
+ pause();
+}
+
+static void sig_handler(int nr)
+{
+ done = 1;
+}
+
+/*
+ * Check the expected timer expiration matches the GTOD elapsed delta since
+ * we armed the timer. Keep a 0.5 sec error margin due to various jitter.
+ */
+static int check_diff(struct timeval start, struct timeval end)
+{
+ long long diff;
+
+ diff = end.tv_usec - start.tv_usec;
+ diff += (end.tv_sec - start.tv_sec) * USECS_PER_SEC;
+
+ if (abs(diff - DELAY * USECS_PER_SEC) > USECS_PER_SEC / 2) {
+ printf("Diff too high: %lld..", diff);
+ return -1;
+ }
+
+ return 0;
+}
+
+static int check_itimer(int which)
+{
+ int err;
+ struct timeval start, end;
+ struct itimerval val = {
+ .it_value.tv_sec = DELAY,
+ };
+
+ printf("Check itimer ");
+
+ if (which == ITIMER_VIRTUAL)
+ printf("virtual... ");
+ else if (which == ITIMER_PROF)
+ printf("prof... ");
+ else if (which == ITIMER_REAL)
+ printf("real... ");
+
+ fflush(stdout);
+
+ done = 0;
+
+ if (which == ITIMER_VIRTUAL)
+ signal(SIGVTALRM, sig_handler);
+ else if (which == ITIMER_PROF)
+ signal(SIGPROF, sig_handler);
+ else if (which == ITIMER_REAL)
+ signal(SIGALRM, sig_handler);
+
+ err = gettimeofday(&start, NULL);
+ if (err < 0) {
+ perror("Can't call gettimeofday()\n");
+ return -1;
+ }
+
+ err = setitimer(which, &val, NULL);
+ if (err < 0) {
+ perror("Can't set timer\n");
+ return -1;
+ }
+
+ if (which == ITIMER_VIRTUAL)
+ user_loop();
+ else if (which == ITIMER_PROF)
+ kernel_loop();
+ else if (which == ITIMER_REAL)
+ idle_loop();
+
+ gettimeofday(&end, NULL);
+ if (err < 0) {
+ perror("Can't call gettimeofday()\n");
+ return -1;
+ }
+
+ if (!check_diff(start, end))
+ printf("[OK]\n");
+ else
+ printf("[FAIL]\n");
+
+ return 0;
+}
+
+static int check_timer_create(int which)
+{
+ int err;
+ timer_t id;
+ struct timeval start, end;
+ struct itimerspec val = {
+ .it_value.tv_sec = DELAY,
+ };
+
+ printf("Check timer_create() ");
+ if (which == CLOCK_THREAD_CPUTIME_ID) {
+ printf("per thread... ");
+ } else if (which == CLOCK_PROCESS_CPUTIME_ID) {
+ printf("per process... ");
+ }
+ fflush(stdout);
+
+ done = 0;
+ timer_create(which, NULL, &id);
+ if (err < 0) {
+ perror("Can't create timer\n");
+ return -1;
+ }
+ signal(SIGALRM, sig_handler);
+
+ err = gettimeofday(&start, NULL);
+ if (err < 0) {
+ perror("Can't call gettimeofday()\n");
+ return -1;
+ }
+
+ err = timer_settime(id, 0, &val, NULL);
+ if (err < 0) {
+ perror("Can't set timer\n");
+ return -1;
+ }
+
+ user_loop();
+
+ gettimeofday(&end, NULL);
+ if (err < 0) {
+ perror("Can't call gettimeofday()\n");
+ return -1;
+ }
+
+ if (!check_diff(start, end))
+ printf("[OK]\n");
+ else
+ printf("[FAIL]\n");
+
+ return 0;
+}
+
+int main(int argc, char **argv)
+{
+ int err;
+
+ printf("Testing posix timers. False negative may happen on CPU execution \n");
+ printf("based timers if other threads run on the CPU...\n");
+
+ if (check_itimer(ITIMER_VIRTUAL) < 0)
+ return -1;
+
+ if (check_itimer(ITIMER_PROF) < 0)
+ return -1;
+
+ if (check_itimer(ITIMER_REAL) < 0)
+ return -1;
+
+ if (check_timer_create(CLOCK_THREAD_CPUTIME_ID) < 0)
+ return -1;
+
+ /*
+ * It's unfortunately hard to reliably test a timer expiration
+ * on parallel multithread cputime. We could arm it to expire
+ * on DELAY * nr_threads, with nr_threads busy looping, then wait
+ * the normal DELAY since the time is elapsing nr_threads faster.
+ * But for that we need to ensure we have real physical free CPUs
+ * to ensure true parallelism. So test only one thread until we
+ * find a better solution.
+ */
+ if (check_timer_create(CLOCK_PROCESS_CPUTIME_ID) < 0)
+ return -1;
+
+ return 0;
+}
--
1.7.5.4
The posix cpu timer expiry time is stored in a union of
two types: a 64 bits field if we rely on scheduler precise
accounting, or a cputime_t if we rely on jiffies.
This result in quite some duplicate code and special cases
to handle the two types.
Just unify this into a single 64 bits field. cputime_t can
always fit into it.
Signed-off-by: Frederic Weisbecker <[email protected]>
Cc: Stanislaw Gruszka <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Oleg Nesterov <[email protected]>
---
include/linux/posix-timers.h | 16 ++-
kernel/posix-cpu-timers.c | 266 +++++++++++++++++-------------------------
2 files changed, 117 insertions(+), 165 deletions(-)
diff --git a/include/linux/posix-timers.h b/include/linux/posix-timers.h
index 042058f..92a51df 100644
--- a/include/linux/posix-timers.h
+++ b/include/linux/posix-timers.h
@@ -7,14 +7,20 @@
#include <linux/timex.h>
#include <linux/alarmtimer.h>
-union cpu_time_count {
- cputime_t cpu;
- unsigned long long sched;
-};
+
+static inline unsigned long long cputime_to_expires(cputime_t expires)
+{
+ return (__force unsigned long long)expires;
+}
+
+static inline cputime_t expires_to_cputime(unsigned long long expires)
+{
+ return (__force cputime_t)expires;
+}
struct cpu_timer_list {
struct list_head entry;
- union cpu_time_count expires, incr;
+ unsigned long long expires, incr;
struct task_struct *task;
int firing;
};
diff --git a/kernel/posix-cpu-timers.c b/kernel/posix-cpu-timers.c
index 8fd709c..e5286b5 100644
--- a/kernel/posix-cpu-timers.c
+++ b/kernel/posix-cpu-timers.c
@@ -49,59 +49,28 @@ static int check_clock(const clockid_t which_clock)
return error;
}
-static inline union cpu_time_count
+static inline unsigned long long
timespec_to_sample(const clockid_t which_clock, const struct timespec *tp)
{
- union cpu_time_count ret;
- ret.sched = 0; /* high half always zero when .cpu used */
+ unsigned long long ret;
+
+ ret = 0; /* high half always zero when .cpu used */
if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED) {
- ret.sched = (unsigned long long)tp->tv_sec * NSEC_PER_SEC + tp->tv_nsec;
+ ret = (unsigned long long)tp->tv_sec * NSEC_PER_SEC + tp->tv_nsec;
} else {
- ret.cpu = timespec_to_cputime(tp);
+ ret = cputime_to_expires(timespec_to_cputime(tp));
}
return ret;
}
static void sample_to_timespec(const clockid_t which_clock,
- union cpu_time_count cpu,
+ unsigned long long expires,
struct timespec *tp)
{
if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED)
- *tp = ns_to_timespec(cpu.sched);
+ *tp = ns_to_timespec(expires);
else
- cputime_to_timespec(cpu.cpu, tp);
-}
-
-static inline int cpu_time_before(const clockid_t which_clock,
- union cpu_time_count now,
- union cpu_time_count then)
-{
- if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED) {
- return now.sched < then.sched;
- } else {
- return now.cpu < then.cpu;
- }
-}
-static inline void cpu_time_add(const clockid_t which_clock,
- union cpu_time_count *acc,
- union cpu_time_count val)
-{
- if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED) {
- acc->sched += val.sched;
- } else {
- acc->cpu += val.cpu;
- }
-}
-static inline union cpu_time_count cpu_time_sub(const clockid_t which_clock,
- union cpu_time_count a,
- union cpu_time_count b)
-{
- if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED) {
- a.sched -= b.sched;
- } else {
- a.cpu -= b.cpu;
- }
- return a;
+ cputime_to_timespec((__force cputime_t)expires, tp);
}
/*
@@ -109,65 +78,49 @@ static inline union cpu_time_count cpu_time_sub(const clockid_t which_clock,
* given the current clock sample.
*/
static void bump_cpu_timer(struct k_itimer *timer,
- union cpu_time_count now)
+ unsigned long long now)
{
int i;
+ unsigned long long delta, incr;
- if (timer->it.cpu.incr.sched == 0)
+ if (timer->it.cpu.incr == 0)
return;
- if (CPUCLOCK_WHICH(timer->it_clock) == CPUCLOCK_SCHED) {
- unsigned long long delta, incr;
+ if (now < timer->it.cpu.expires)
+ return;
- if (now.sched < timer->it.cpu.expires.sched)
- return;
- incr = timer->it.cpu.incr.sched;
- delta = now.sched + incr - timer->it.cpu.expires.sched;
- /* Don't use (incr*2 < delta), incr*2 might overflow. */
- for (i = 0; incr < delta - incr; i++)
- incr = incr << 1;
- for (; i >= 0; incr >>= 1, i--) {
- if (delta < incr)
- continue;
- timer->it.cpu.expires.sched += incr;
- timer->it_overrun += 1 << i;
- delta -= incr;
- }
- } else {
- cputime_t delta, incr;
+ incr = timer->it.cpu.incr;
+ delta = now + incr - timer->it.cpu.expires;
- if (now.cpu < timer->it.cpu.expires.cpu)
- return;
- incr = timer->it.cpu.incr.cpu;
- delta = now.cpu + incr - timer->it.cpu.expires.cpu;
- /* Don't use (incr*2 < delta), incr*2 might overflow. */
- for (i = 0; incr < delta - incr; i++)
- incr += incr;
- for (; i >= 0; incr = incr >> 1, i--) {
- if (delta < incr)
- continue;
- timer->it.cpu.expires.cpu += incr;
- timer->it_overrun += 1 << i;
- delta -= incr;
- }
+ /* Don't use (incr*2 < delta), incr*2 might overflow. */
+ for (i = 0; incr < delta - incr; i++)
+ incr = incr << 1;
+
+ for (; i >= 0; incr >>= 1, i--) {
+ if (delta < incr)
+ continue;
+
+ timer->it.cpu.expires += incr;
+ timer->it_overrun += 1 << i;
+ delta -= incr;
}
}
-static inline cputime_t prof_ticks(struct task_struct *p)
+static inline unsigned long long prof_ticks(struct task_struct *p)
{
cputime_t utime, stime;
task_cputime(p, &utime, &stime);
- return utime + stime;
+ return cputime_to_expires(utime + stime);
}
-static inline cputime_t virt_ticks(struct task_struct *p)
+static inline unsigned long long virt_ticks(struct task_struct *p)
{
cputime_t utime;
task_cputime(p, &utime, NULL);
- return utime;
+ return cputime_to_expires(utime);
}
static int
@@ -208,19 +161,19 @@ posix_cpu_clock_set(const clockid_t which_clock, const struct timespec *tp)
* Sample a per-thread clock for the given task.
*/
static int cpu_clock_sample(const clockid_t which_clock, struct task_struct *p,
- union cpu_time_count *cpu)
+ unsigned long long *sample)
{
switch (CPUCLOCK_WHICH(which_clock)) {
default:
return -EINVAL;
case CPUCLOCK_PROF:
- cpu->cpu = prof_ticks(p);
+ *sample = prof_ticks(p);
break;
case CPUCLOCK_VIRT:
- cpu->cpu = virt_ticks(p);
+ *sample = virt_ticks(p);
break;
case CPUCLOCK_SCHED:
- cpu->sched = task_sched_runtime(p);
+ *sample = task_sched_runtime(p);
break;
}
return 0;
@@ -267,7 +220,7 @@ void thread_group_cputimer(struct task_struct *tsk, struct task_cputime *times)
*/
static int cpu_clock_sample_group(const clockid_t which_clock,
struct task_struct *p,
- union cpu_time_count *cpu)
+ unsigned long long *sample)
{
struct task_cputime cputime;
@@ -276,15 +229,15 @@ static int cpu_clock_sample_group(const clockid_t which_clock,
return -EINVAL;
case CPUCLOCK_PROF:
thread_group_cputime(p, &cputime);
- cpu->cpu = cputime.utime + cputime.stime;
+ *sample = cputime_to_expires(cputime.utime + cputime.stime);
break;
case CPUCLOCK_VIRT:
thread_group_cputime(p, &cputime);
- cpu->cpu = cputime.utime;
+ *sample = cputime_to_expires(cputime.utime);
break;
case CPUCLOCK_SCHED:
thread_group_cputime(p, &cputime);
- cpu->sched = cputime.sum_exec_runtime;
+ *sample = cputime.sum_exec_runtime;
break;
}
return 0;
@@ -295,7 +248,7 @@ static int posix_cpu_clock_get(const clockid_t which_clock, struct timespec *tp)
{
const pid_t pid = CPUCLOCK_PID(which_clock);
int error = -EINVAL;
- union cpu_time_count rtn;
+ unsigned long long rtn;
if (pid == 0) {
/*
@@ -444,30 +397,30 @@ static void cleanup_timers(struct list_head *head,
list_for_each_entry_safe(timer, next, head, entry) {
list_del_init(&timer->entry);
- if (timer->expires.cpu < ptime) {
- timer->expires.cpu = 0;
+ if (timer->expires < cputime_to_expires(ptime)) {
+ timer->expires = 0;
} else {
- timer->expires.cpu -= ptime;
+ timer->expires -= cputime_to_expires(ptime);
}
}
++head;
list_for_each_entry_safe(timer, next, head, entry) {
list_del_init(&timer->entry);
- if (timer->expires.cpu < utime) {
- timer->expires.cpu = 0;
+ if (timer->expires < cputime_to_expires(utime)) {
+ timer->expires = 0;
} else {
- timer->expires.cpu -= utime;
+ timer->expires -= cputime_to_expires(utime);
}
}
++head;
list_for_each_entry_safe(timer, next, head, entry) {
list_del_init(&timer->entry);
- if (timer->expires.sched < sum_exec_runtime) {
- timer->expires.sched = 0;
+ if (timer->expires < sum_exec_runtime) {
+ timer->expires = 0;
} else {
- timer->expires.sched -= sum_exec_runtime;
+ timer->expires -= sum_exec_runtime;
}
}
}
@@ -499,7 +452,7 @@ void posix_cpu_timers_exit_group(struct task_struct *tsk)
tsk->se.sum_exec_runtime + sig->sum_sched_runtime);
}
-static void clear_dead_task(struct k_itimer *timer, union cpu_time_count now)
+static void clear_dead_task(struct k_itimer *timer, unsigned long long now)
{
/*
* That's all for this thread or process.
@@ -507,9 +460,7 @@ static void clear_dead_task(struct k_itimer *timer, union cpu_time_count now)
*/
put_task_struct(timer->it.cpu.task);
timer->it.cpu.task = NULL;
- timer->it.cpu.expires = cpu_time_sub(timer->it_clock,
- timer->it.cpu.expires,
- now);
+ timer->it.cpu.expires -= now;
}
static inline int expires_gt(cputime_t expires, cputime_t new_exp)
@@ -541,14 +492,14 @@ static void arm_timer(struct k_itimer *timer)
listpos = head;
list_for_each_entry(next, head, entry) {
- if (cpu_time_before(timer->it_clock, nt->expires, next->expires))
+ if (nt->expires < next->expires)
break;
listpos = &next->entry;
}
list_add(&nt->entry, listpos);
if (listpos == head) {
- union cpu_time_count *exp = &nt->expires;
+ unsigned long long exp = nt->expires;
/*
* We are the new earliest-expiring POSIX 1.b timer, hence
@@ -559,17 +510,17 @@ static void arm_timer(struct k_itimer *timer)
switch (CPUCLOCK_WHICH(timer->it_clock)) {
case CPUCLOCK_PROF:
- if (expires_gt(cputime_expires->prof_exp, exp->cpu))
- cputime_expires->prof_exp = exp->cpu;
+ if (expires_gt(cputime_expires->prof_exp, expires_to_cputime(exp)))
+ cputime_expires->prof_exp = expires_to_cputime(exp);
break;
case CPUCLOCK_VIRT:
- if (expires_gt(cputime_expires->virt_exp, exp->cpu))
- cputime_expires->virt_exp = exp->cpu;
+ if (expires_gt(cputime_expires->virt_exp, expires_to_cputime(exp)))
+ cputime_expires->virt_exp = expires_to_cputime(exp);
break;
case CPUCLOCK_SCHED:
if (cputime_expires->sched_exp == 0 ||
- cputime_expires->sched_exp > exp->sched)
- cputime_expires->sched_exp = exp->sched;
+ cputime_expires->sched_exp > exp)
+ cputime_expires->sched_exp = exp;
break;
}
}
@@ -584,20 +535,20 @@ static void cpu_timer_fire(struct k_itimer *timer)
/*
* User don't want any signal.
*/
- timer->it.cpu.expires.sched = 0;
+ timer->it.cpu.expires = 0;
} else if (unlikely(timer->sigq == NULL)) {
/*
* This a special case for clock_nanosleep,
* not a normal timer from sys_timer_create.
*/
wake_up_process(timer->it_process);
- timer->it.cpu.expires.sched = 0;
- } else if (timer->it.cpu.incr.sched == 0) {
+ timer->it.cpu.expires = 0;
+ } else if (timer->it.cpu.incr == 0) {
/*
* One-shot timer. Clear it as soon as it's fired.
*/
posix_timer_event(timer, 0);
- timer->it.cpu.expires.sched = 0;
+ timer->it.cpu.expires = 0;
} else if (posix_timer_event(timer, ++timer->it_requeue_pending)) {
/*
* The signal did not get queued because the signal
@@ -615,7 +566,7 @@ static void cpu_timer_fire(struct k_itimer *timer)
*/
static int cpu_timer_sample_group(const clockid_t which_clock,
struct task_struct *p,
- union cpu_time_count *cpu)
+ unsigned long long *sample)
{
struct task_cputime cputime;
@@ -624,13 +575,13 @@ static int cpu_timer_sample_group(const clockid_t which_clock,
default:
return -EINVAL;
case CPUCLOCK_PROF:
- cpu->cpu = cputime.utime + cputime.stime;
+ *sample = cputime_to_expires(cputime.utime + cputime.stime);
break;
case CPUCLOCK_VIRT:
- cpu->cpu = cputime.utime;
+ *sample = cputime_to_expires(cputime.utime);
break;
case CPUCLOCK_SCHED:
- cpu->sched = cputime.sum_exec_runtime + task_delta_exec(p);
+ *sample = cputime.sum_exec_runtime + task_delta_exec(p);
break;
}
return 0;
@@ -646,7 +597,7 @@ static int posix_cpu_timer_set(struct k_itimer *timer, int flags,
struct itimerspec *new, struct itimerspec *old)
{
struct task_struct *p = timer->it.cpu.task;
- union cpu_time_count old_expires, new_expires, old_incr, val;
+ unsigned long long old_expires, new_expires, old_incr, val;
int ret;
if (unlikely(p == NULL)) {
@@ -701,7 +652,7 @@ static int posix_cpu_timer_set(struct k_itimer *timer, int flags,
}
if (old) {
- if (old_expires.sched == 0) {
+ if (old_expires == 0) {
old->it_value.tv_sec = 0;
old->it_value.tv_nsec = 0;
} else {
@@ -716,11 +667,8 @@ static int posix_cpu_timer_set(struct k_itimer *timer, int flags,
* new setting.
*/
bump_cpu_timer(timer, val);
- if (cpu_time_before(timer->it_clock, val,
- timer->it.cpu.expires)) {
- old_expires = cpu_time_sub(
- timer->it_clock,
- timer->it.cpu.expires, val);
+ if (val < timer->it.cpu.expires) {
+ old_expires = timer->it.cpu.expires - val;
sample_to_timespec(timer->it_clock,
old_expires,
&old->it_value);
@@ -743,8 +691,8 @@ static int posix_cpu_timer_set(struct k_itimer *timer, int flags,
goto out;
}
- if (new_expires.sched != 0 && !(flags & TIMER_ABSTIME)) {
- cpu_time_add(timer->it_clock, &new_expires, val);
+ if (new_expires != 0 && !(flags & TIMER_ABSTIME)) {
+ new_expires += val;
}
/*
@@ -753,8 +701,7 @@ static int posix_cpu_timer_set(struct k_itimer *timer, int flags,
* arm the timer (we'll just fake it for timer_gettime).
*/
timer->it.cpu.expires = new_expires;
- if (new_expires.sched != 0 &&
- cpu_time_before(timer->it_clock, val, new_expires)) {
+ if (new_expires != 0 && val < new_expires) {
arm_timer(timer);
}
@@ -778,8 +725,7 @@ static int posix_cpu_timer_set(struct k_itimer *timer, int flags,
timer->it_overrun_last = 0;
timer->it_overrun = -1;
- if (new_expires.sched != 0 &&
- !cpu_time_before(timer->it_clock, val, new_expires)) {
+ if (new_expires != 0 && !(val < new_expires)) {
/*
* The designated time already passed, so we notify
* immediately, even if the thread never runs to
@@ -799,7 +745,7 @@ static int posix_cpu_timer_set(struct k_itimer *timer, int flags,
static void posix_cpu_timer_get(struct k_itimer *timer, struct itimerspec *itp)
{
- union cpu_time_count now;
+ unsigned long long now;
struct task_struct *p = timer->it.cpu.task;
int clear_dead;
@@ -809,7 +755,7 @@ static void posix_cpu_timer_get(struct k_itimer *timer, struct itimerspec *itp)
sample_to_timespec(timer->it_clock,
timer->it.cpu.incr, &itp->it_interval);
- if (timer->it.cpu.expires.sched == 0) { /* Timer not armed at all. */
+ if (timer->it.cpu.expires == 0) { /* Timer not armed at all. */
itp->it_value.tv_sec = itp->it_value.tv_nsec = 0;
return;
}
@@ -841,7 +787,7 @@ static void posix_cpu_timer_get(struct k_itimer *timer, struct itimerspec *itp)
*/
put_task_struct(p);
timer->it.cpu.task = NULL;
- timer->it.cpu.expires.sched = 0;
+ timer->it.cpu.expires = 0;
read_unlock(&tasklist_lock);
goto dead;
} else {
@@ -862,10 +808,9 @@ static void posix_cpu_timer_get(struct k_itimer *timer, struct itimerspec *itp)
goto dead;
}
- if (cpu_time_before(timer->it_clock, now, timer->it.cpu.expires)) {
+ if (now < timer->it.cpu.expires) {
sample_to_timespec(timer->it_clock,
- cpu_time_sub(timer->it_clock,
- timer->it.cpu.expires, now),
+ timer->it.cpu.expires - now,
&itp->it_value);
} else {
/*
@@ -896,8 +841,8 @@ static void check_thread_timers(struct task_struct *tsk,
struct cpu_timer_list *t = list_first_entry(timers,
struct cpu_timer_list,
entry);
- if (!--maxfire || prof_ticks(tsk) < t->expires.cpu) {
- tsk->cputime_expires.prof_exp = t->expires.cpu;
+ if (!--maxfire || prof_ticks(tsk) < t->expires) {
+ tsk->cputime_expires.prof_exp = expires_to_cputime(t->expires);
break;
}
t->firing = 1;
@@ -911,8 +856,8 @@ static void check_thread_timers(struct task_struct *tsk,
struct cpu_timer_list *t = list_first_entry(timers,
struct cpu_timer_list,
entry);
- if (!--maxfire || virt_ticks(tsk) < t->expires.cpu) {
- tsk->cputime_expires.virt_exp = t->expires.cpu;
+ if (!--maxfire || virt_ticks(tsk) < t->expires) {
+ tsk->cputime_expires.virt_exp = expires_to_cputime(t->expires);
break;
}
t->firing = 1;
@@ -926,8 +871,8 @@ static void check_thread_timers(struct task_struct *tsk,
struct cpu_timer_list *t = list_first_entry(timers,
struct cpu_timer_list,
entry);
- if (!--maxfire || tsk->se.sum_exec_runtime < t->expires.sched) {
- tsk->cputime_expires.sched_exp = t->expires.sched;
+ if (!--maxfire || tsk->se.sum_exec_runtime < t->expires) {
+ tsk->cputime_expires.sched_exp = t->expires;
break;
}
t->firing = 1;
@@ -980,7 +925,8 @@ static void stop_process_timers(struct signal_struct *sig)
static u32 onecputick;
static void check_cpu_itimer(struct task_struct *tsk, struct cpu_itimer *it,
- cputime_t *expires, cputime_t cur_time, int signo)
+ unsigned long long *expires,
+ unsigned long long cur_time, int signo)
{
if (!it->expires)
return;
@@ -1033,7 +979,7 @@ static void check_process_timers(struct task_struct *tsk,
{
int maxfire;
struct signal_struct *const sig = tsk->signal;
- cputime_t utime, ptime, virt_expires, prof_expires;
+ unsigned long long utime, ptime, virt_expires, prof_expires;
unsigned long long sum_sched_runtime, sched_expires;
struct list_head *timers = sig->cpu_timers;
struct task_cputime cputime;
@@ -1043,8 +989,8 @@ static void check_process_timers(struct task_struct *tsk,
* Collect the current process totals.
*/
thread_group_cputimer(tsk, &cputime);
- utime = cputime.utime;
- ptime = utime + cputime.stime;
+ utime = cputime_to_expires(cputime.utime);
+ ptime = utime + cputime_to_expires(cputime.stime);
sum_sched_runtime = cputime.sum_exec_runtime;
maxfire = 20;
prof_expires = 0;
@@ -1052,8 +998,8 @@ static void check_process_timers(struct task_struct *tsk,
struct cpu_timer_list *tl = list_first_entry(timers,
struct cpu_timer_list,
entry);
- if (!--maxfire || ptime < tl->expires.cpu) {
- prof_expires = tl->expires.cpu;
+ if (!--maxfire || ptime < tl->expires) {
+ prof_expires = tl->expires;
break;
}
tl->firing = 1;
@@ -1067,8 +1013,8 @@ static void check_process_timers(struct task_struct *tsk,
struct cpu_timer_list *tl = list_first_entry(timers,
struct cpu_timer_list,
entry);
- if (!--maxfire || utime < tl->expires.cpu) {
- virt_expires = tl->expires.cpu;
+ if (!--maxfire || utime < tl->expires) {
+ virt_expires = tl->expires;
break;
}
tl->firing = 1;
@@ -1082,8 +1028,8 @@ static void check_process_timers(struct task_struct *tsk,
struct cpu_timer_list *tl = list_first_entry(timers,
struct cpu_timer_list,
entry);
- if (!--maxfire || sum_sched_runtime < tl->expires.sched) {
- sched_expires = tl->expires.sched;
+ if (!--maxfire || sum_sched_runtime < tl->expires) {
+ sched_expires = tl->expires;
break;
}
tl->firing = 1;
@@ -1127,8 +1073,8 @@ static void check_process_timers(struct task_struct *tsk,
}
}
- sig->cputime_expires.prof_exp = prof_expires;
- sig->cputime_expires.virt_exp = virt_expires;
+ sig->cputime_expires.prof_exp = expires_to_cputime(prof_expires);
+ sig->cputime_expires.virt_exp = expires_to_cputime(virt_expires);
sig->cputime_expires.sched_exp = sched_expires;
if (task_cputime_zero(&sig->cputime_expires))
stop_process_timers(sig);
@@ -1141,7 +1087,7 @@ static void check_process_timers(struct task_struct *tsk,
void posix_cpu_timer_schedule(struct k_itimer *timer)
{
struct task_struct *p = timer->it.cpu.task;
- union cpu_time_count now;
+ unsigned long long now;
if (unlikely(p == NULL))
/*
@@ -1170,7 +1116,7 @@ void posix_cpu_timer_schedule(struct k_itimer *timer)
*/
put_task_struct(p);
timer->it.cpu.task = p = NULL;
- timer->it.cpu.expires.sched = 0;
+ timer->it.cpu.expires = 0;
goto out_unlock;
} else if (unlikely(p->exit_state) && thread_group_empty(p)) {
/*
@@ -1345,7 +1291,7 @@ void run_posix_cpu_timers(struct task_struct *tsk)
void set_process_cpu_timer(struct task_struct *tsk, unsigned int clock_idx,
cputime_t *newval, cputime_t *oldval)
{
- union cpu_time_count now;
+ unsigned long long now;
BUG_ON(clock_idx == CPUCLOCK_SCHED);
cpu_timer_sample_group(clock_idx, tsk, &now);
@@ -1357,17 +1303,17 @@ void set_process_cpu_timer(struct task_struct *tsk, unsigned int clock_idx,
* it to be absolute.
*/
if (*oldval) {
- if (*oldval <= now.cpu) {
+ if (*oldval <= now) {
/* Just about to fire. */
*oldval = cputime_one_jiffy;
} else {
- *oldval -= now.cpu;
+ *oldval -= now;
}
}
if (!*newval)
return;
- *newval += now.cpu;
+ *newval += now;
}
/*
@@ -1415,7 +1361,7 @@ static int do_cpu_nanosleep(const clockid_t which_clock, int flags,
}
while (!signal_pending(current)) {
- if (timer.it.cpu.expires.sched == 0) {
+ if (timer.it.cpu.expires == 0) {
/*
* Our timer fired and was reset, below
* deletion can not fail.
--
1.7.5.4
Cleaning up the posix cpu timers on task exit shares
some common code among timer list types, most notably the
list traversal and expiry time update.
Unify this in a common helper.
Signed-off-by: Frederic Weisbecker <[email protected]>
Cc: Stanislaw Gruszka <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Oleg Nesterov <[email protected]>
---
kernel/posix-cpu-timers.c | 48 +++++++++++++++++---------------------------
1 files changed, 19 insertions(+), 29 deletions(-)
diff --git a/kernel/posix-cpu-timers.c b/kernel/posix-cpu-timers.c
index e5286b5..b30775f 100644
--- a/kernel/posix-cpu-timers.c
+++ b/kernel/posix-cpu-timers.c
@@ -382,6 +382,21 @@ static int posix_cpu_timer_del(struct k_itimer *timer)
return ret;
}
+static void cleanup_timers_list(struct list_head *head,
+ unsigned long long curr)
+{
+ struct cpu_timer_list *timer, *next;
+
+ list_for_each_entry_safe(timer, next, head, entry) {
+ list_del_init(&timer->entry);
+ if (timer->expires < curr) {
+ timer->expires = 0;
+ } else {
+ timer->expires -= curr;
+ }
+ }
+}
+
/*
* Clean out CPU timers still ticking when a thread exited. The task
* pointer is cleared, and the expiry time is replaced with the residual
@@ -392,37 +407,12 @@ static void cleanup_timers(struct list_head *head,
cputime_t utime, cputime_t stime,
unsigned long long sum_exec_runtime)
{
- struct cpu_timer_list *timer, *next;
- cputime_t ptime = utime + stime;
- list_for_each_entry_safe(timer, next, head, entry) {
- list_del_init(&timer->entry);
- if (timer->expires < cputime_to_expires(ptime)) {
- timer->expires = 0;
- } else {
- timer->expires -= cputime_to_expires(ptime);
- }
- }
-
- ++head;
- list_for_each_entry_safe(timer, next, head, entry) {
- list_del_init(&timer->entry);
- if (timer->expires < cputime_to_expires(utime)) {
- timer->expires = 0;
- } else {
- timer->expires -= cputime_to_expires(utime);
- }
- }
+ cputime_t ptime = utime + stime;
- ++head;
- list_for_each_entry_safe(timer, next, head, entry) {
- list_del_init(&timer->entry);
- if (timer->expires < sum_exec_runtime) {
- timer->expires = 0;
- } else {
- timer->expires -= sum_exec_runtime;
- }
- }
+ cleanup_timers_list(head, cputime_to_expires(ptime));
+ cleanup_timers_list(++head, cputime_to_expires(utime));
+ cleanup_timers_list(++head, sum_exec_runtime);
}
/*
--
1.7.5.4
On Fri, 15 Mar 2013 17:54:02 +0100 Frederic Weisbecker <[email protected]> wrote:
> Add some initial basic tests on a few posix timers
> interface such as setitimer() and timer_settime().
>
> These simply check that expiration happens in a reasonable
> timeframe after expected elapsed clock time (user time,
> user + system time, real time, ...).
>
> This is helpful for finding basic breakages while hacking
> on this subsystem.
>
> ...
>
> tools/testing/selftests/timers/Makefile | 8 +
I wonder if this should be tools/testing/posix-timers/, to leave room
in the namespace for other varieties of timer.
2013/3/18 Andrew Morton <[email protected]>:
> On Fri, 15 Mar 2013 17:54:02 +0100 Frederic Weisbecker <[email protected]> wrote:
>
>> Add some initial basic tests on a few posix timers
>> interface such as setitimer() and timer_settime().
>>
>> These simply check that expiration happens in a reasonable
>> timeframe after expected elapsed clock time (user time,
>> user + system time, real time, ...).
>>
>> This is helpful for finding basic breakages while hacking
>> on this subsystem.
>>
>> ...
>>
>> tools/testing/selftests/timers/Makefile | 8 +
>
> I wonder if this should be tools/testing/posix-timers/, to leave room
> in the namespace for other varieties of timer.
In fact I called it timers/ on purpose such that some more timers
related selftests can be added and gathered in the future. But I don't
mind if we keep very single purpose directories like
tools/testing/posix-timers/
On Fri, 15 Mar 2013 17:53:59 +0100 Frederic Weisbecker <[email protected]> wrote:
> The posix cpu timer expiry time is stored in a union of
> two types: a 64 bits field if we rely on scheduler precise
> accounting, or a cputime_t if we rely on jiffies.
>
> This result in quite some duplicate code and special cases
> to handle the two types.
>
> Just unify this into a single 64 bits field. cputime_t can
> always fit into it.
>
x86_64 allnoconfig:
kernel/posix-cpu-timers.c: In function 'posix_cpu_timer_schedule':
kernel/posix-cpu-timers.c:1127: warning: 'now' may be used uninitialized in this function
It looks like it's always been buggy, but your switch from `union
cou_time_count' to `unsigned long long' made gcc notice it.
2013/3/19 Andrew Morton <[email protected]>:
> On Fri, 15 Mar 2013 17:53:59 +0100 Frederic Weisbecker <[email protected]> wrote:
>
>> The posix cpu timer expiry time is stored in a union of
>> two types: a 64 bits field if we rely on scheduler precise
>> accounting, or a cputime_t if we rely on jiffies.
>>
>> This result in quite some duplicate code and special cases
>> to handle the two types.
>>
>> Just unify this into a single 64 bits field. cputime_t can
>> always fit into it.
>>
>
> x86_64 allnoconfig:
>
> kernel/posix-cpu-timers.c: In function 'posix_cpu_timer_schedule':
> kernel/posix-cpu-timers.c:1127: warning: 'now' may be used uninitialized in this function
>
> It looks like it's always been buggy, but your switch from `union
> cou_time_count' to `unsigned long long' made gcc notice it.
Ok, from a quick view it seems what's missing is a call to
cpu_timer_sample_group() to compute the residual time for further call
of timer_gettime(). I'll look at it deeper and send you a fix.
Thanks.