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-rw-r--r--include/linux/sched.h2
-rw-r--r--kernel/itimer.c24
-rw-r--r--kernel/posix-cpu-timers.c20
3 files changed, 40 insertions, 6 deletions
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 3b3efaddd953..a069e65e8bb7 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -473,6 +473,8 @@ struct pacct_struct {
struct cpu_itimer {
cputime_t expires;
cputime_t incr;
+ u32 error;
+ u32 incr_error;
};
/**
diff --git a/kernel/itimer.c b/kernel/itimer.c
index 852c88ddd1f0..21adff7b2a17 100644
--- a/kernel/itimer.c
+++ b/kernel/itimer.c
@@ -42,7 +42,7 @@ static struct timeval itimer_get_remtime(struct hrtimer *timer)
}
static void get_cpu_itimer(struct task_struct *tsk, unsigned int clock_id,
- struct itimerval *value)
+ struct itimerval *const value)
{
cputime_t cval, cinterval;
struct cpu_itimer *it = &tsk->signal->it[clock_id];
@@ -127,14 +127,32 @@ enum hrtimer_restart it_real_fn(struct hrtimer *timer)
return HRTIMER_NORESTART;
}
+static inline u32 cputime_sub_ns(cputime_t ct, s64 real_ns)
+{
+ struct timespec ts;
+ s64 cpu_ns;
+
+ cputime_to_timespec(ct, &ts);
+ cpu_ns = timespec_to_ns(&ts);
+
+ return (cpu_ns <= real_ns) ? 0 : cpu_ns - real_ns;
+}
+
static void set_cpu_itimer(struct task_struct *tsk, unsigned int clock_id,
- struct itimerval *value, struct itimerval *ovalue)
+ const struct itimerval *const value,
+ struct itimerval *const ovalue)
{
- cputime_t cval, cinterval, nval, ninterval;
+ cputime_t cval, nval, cinterval, ninterval;
+ s64 ns_ninterval, ns_nval;
struct cpu_itimer *it = &tsk->signal->it[clock_id];
nval = timeval_to_cputime(&value->it_value);
+ ns_nval = timeval_to_ns(&value->it_value);
ninterval = timeval_to_cputime(&value->it_interval);
+ ns_ninterval = timeval_to_ns(&value->it_interval);
+
+ it->incr_error = cputime_sub_ns(ninterval, ns_ninterval);
+ it->error = cputime_sub_ns(nval, ns_nval);
spin_lock_irq(&tsk->sighand->siglock);
diff --git a/kernel/posix-cpu-timers.c b/kernel/posix-cpu-timers.c
index 9b2d5e4dc8c4..b60d644ea4b3 100644
--- a/kernel/posix-cpu-timers.c
+++ b/kernel/posix-cpu-timers.c
@@ -1070,6 +1070,8 @@ static void stop_process_timers(struct task_struct *tsk)
spin_unlock_irqrestore(&cputimer->lock, flags);
}
+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)
{
@@ -1077,9 +1079,16 @@ static void check_cpu_itimer(struct task_struct *tsk, struct cpu_itimer *it,
return;
if (cputime_ge(cur_time, it->expires)) {
- it->expires = it->incr;
- if (!cputime_eq(it->expires, cputime_zero))
- it->expires = cputime_add(it->expires, cur_time);
+ if (!cputime_eq(it->incr, cputime_zero)) {
+ it->expires = cputime_add(it->expires, it->incr);
+ it->error += it->incr_error;
+ if (it->error >= onecputick) {
+ it->expires = cputime_sub(it->expires,
+ jiffies_to_cputime(1));
+ it->error -= onecputick;
+ }
+ } else
+ it->expires = cputime_zero;
__group_send_sig_info(signo, SEND_SIG_PRIV, tsk);
}
@@ -1696,10 +1705,15 @@ static __init int init_posix_cpu_timers(void)
.nsleep = thread_cpu_nsleep,
.nsleep_restart = thread_cpu_nsleep_restart,
};
+ struct timespec ts;
register_posix_clock(CLOCK_PROCESS_CPUTIME_ID, &process);
register_posix_clock(CLOCK_THREAD_CPUTIME_ID, &thread);
+ cputime_to_timespec(jiffies_to_cputime(1), &ts);
+ onecputick = ts.tv_nsec;
+ WARN_ON(ts.tv_sec != 0);
+
return 0;
}
__initcall(init_posix_cpu_timers);