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Cputime cleanups on reader side:

Browse Source 
* Improve naming and code location
 
 * Consolidate adjustment code
 
 * Comment the adjustement code
 
 Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
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Merge tag 'cputime-adjustment-cleanups' of git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks into sched/core

Pull cputime cleanups from Frederic Weisbecker:

 * Improve naming and code location

 * Consolidate adjustment code

 * Comment the adjustement code

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Ingo Molnar 2012-12-08 15:31:07 +01:00
commit e783377e93
13 changed files with 119 additions and 205 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
fs/proc/array.c
View File

@ -438,7 +438,7 @@ static int do_task_stat(struct seq_file *m, struct pid_namespace *ns,
min_flt += sig->min_flt;
maj_flt += sig->maj_flt;
thread_group_times(task, &utime, &stime);
thread_group_cputime_adjusted(task, &utime, &stime);
gtime += sig->gtime;
}
@ -454,7 +454,7 @@ static int do_task_stat(struct seq_file *m, struct pid_namespace *ns,
if (!whole) {
min_flt = task->min_flt;
maj_flt = task->maj_flt;
task_times(task, &utime, &stime);
task_cputime_adjusted(task, &utime, &stime);
gtime = task->gtime;
}

78
fs/proc/base.c
View File

@ -1272,81 +1272,6 @@ static const struct file_operations proc_pid_sched_operations = {
#endif
#ifdef CONFIG_SCHED_AUTOGROUP
/*
* Print out autogroup related information:
*/
static int sched_autogroup_show(struct seq_file *m, void *v)
{
struct inode *inode = m->private;
struct task_struct *p;
p = get_proc_task(inode);
if (!p)
return -ESRCH;
proc_sched_autogroup_show_task(p, m);
put_task_struct(p);
return 0;
}
static ssize_t
sched_autogroup_write(struct file *file, const char __user *buf,
size_t count, loff_t *offset)
{
struct inode *inode = file->f_path.dentry->d_inode;
struct task_struct *p;
char buffer[PROC_NUMBUF];
int nice;
int err;
memset(buffer, 0, sizeof(buffer));
if (count > sizeof(buffer) - 1)
count = sizeof(buffer) - 1;
if (copy_from_user(buffer, buf, count))
return -EFAULT;
err = kstrtoint(strstrip(buffer), 0, &nice);
if (err < 0)
return err;
p = get_proc_task(inode);
if (!p)
return -ESRCH;
err = proc_sched_autogroup_set_nice(p, nice);
if (err)
count = err;
put_task_struct(p);
return count;
}
static int sched_autogroup_open(struct inode *inode, struct file *filp)
{
int ret;
ret = single_open(filp, sched_autogroup_show, NULL);
if (!ret) {
struct seq_file *m = filp->private_data;
m->private = inode;
}
return ret;
}
static const struct file_operations proc_pid_sched_autogroup_operations = {
.open = sched_autogroup_open,
.read = seq_read,
.write = sched_autogroup_write,
.llseek = seq_lseek,
.release = single_release,
};
#endif /* CONFIG_SCHED_AUTOGROUP */
static ssize_t comm_write(struct file *file, const char __user *buf,
size_t count, loff_t *offset)
{
@ -2657,9 +2582,6 @@ static const struct pid_entry tgid_base_stuff[] = {
INF("limits", S_IRUGO, proc_pid_limits),
#ifdef CONFIG_SCHED_DEBUG
REG("sched", S_IRUGO|S_IWUSR, proc_pid_sched_operations),
#endif
#ifdef CONFIG_SCHED_AUTOGROUP
REG("autogroup", S_IRUGO|S_IWUSR, proc_pid_sched_autogroup_operations),
#endif
REG("comm", S_IRUGO|S_IWUSR, proc_pid_set_comm_operations),
#ifdef CONFIG_HAVE_ARCH_TRACEHOOK

27
include/linux/sched.h
View File

@ -433,14 +433,29 @@ struct cpu_itimer {
u32 incr_error;
};
/**
* struct cputime - snaphsot of system and user cputime
* @utime: time spent in user mode
* @stime: time spent in system mode
*
* Gathers a generic snapshot of user and system time.
*/
struct cputime {
cputime_t utime;
cputime_t stime;
};
/**
* struct task_cputime - collected CPU time counts
* @utime: time spent in user mode, in &cputime_t units
* @stime: time spent in kernel mode, in &cputime_t units
* @sum_exec_runtime: total time spent on the CPU, in nanoseconds
*
* This structure groups together three kinds of CPU time that are
* tracked for threads and thread groups. Most things considering
* This is an extension of struct cputime that includes the total runtime
* spent by the task from the scheduler point of view.
*
* As a result, this structure groups together three kinds of CPU time
* that are tracked for threads and thread groups. Most things considering
* CPU time want to group these counts together and treat all three
* of them in parallel.
*/
@ -581,7 +596,7 @@ struct signal_struct {
cputime_t gtime;
cputime_t cgtime;
#ifndef CONFIG_VIRT_CPU_ACCOUNTING
cputime_t prev_utime, prev_stime;
struct cputime prev_cputime;
#endif
unsigned long nvcsw, nivcsw, cnvcsw, cnivcsw;
unsigned long min_flt, maj_flt, cmin_flt, cmaj_flt;
@ -1340,7 +1355,7 @@ struct task_struct {
cputime_t utime, stime, utimescaled, stimescaled;
cputime_t gtime;
#ifndef CONFIG_VIRT_CPU_ACCOUNTING
cputime_t prev_utime, prev_stime;
struct cputime prev_cputime;
#endif
unsigned long nvcsw, nivcsw; /* context switch counts */
struct timespec start_time; /* monotonic time */
@ -1751,8 +1766,8 @@ static inline void put_task_struct(struct task_struct *t)
__put_task_struct(t);
}
extern void task_times(struct task_struct *p, cputime_t *ut, cputime_t *st);
extern void thread_group_times(struct task_struct *p, cputime_t *ut, cputime_t *st);
extern void task_cputime_adjusted(struct task_struct *p, cputime_t *ut, cputime_t *st);
extern void thread_group_cputime_adjusted(struct task_struct *p, cputime_t *ut, cputime_t *st);
/*
* Per process flags

4
kernel/exit.c
View File

@ -1186,11 +1186,11 @@ static int wait_task_zombie(struct wait_opts *wo, struct task_struct *p)
* as other threads in the parent group can be right
* here reaping other children at the same time.
*
* We use thread_group_times() to get times for the thread
* We use thread_group_cputime_adjusted() to get times for the thread
* group, which consolidates times for all threads in the
* group including the group leader.
*/
thread_group_times(p, &tgutime, &tgstime);
thread_group_cputime_adjusted(p, &tgutime, &tgstime);
spin_lock_irq(&p->real_parent->sighand->siglock);
psig = p->real_parent->signal;
sig = p->signal;

2
kernel/fork.c
View File

@ -1222,7 +1222,7 @@ static struct task_struct *copy_process(unsigned long clone_flags,
p->utime = p->stime = p->gtime = 0;
p->utimescaled = p->stimescaled = 0;
#ifndef CONFIG_VIRT_CPU_ACCOUNTING
p->prev_utime = p->prev_stime = 0;
p->prev_cputime.utime = p->prev_cputime.stime = 0;
#endif
#if defined(SPLIT_RSS_COUNTING)
memset(&p->rss_stat, 0, sizeof(p->rss_stat));

24
kernel/posix-cpu-timers.c
View File

@ -217,30 +217,6 @@ static int cpu_clock_sample(const clockid_t which_clock, struct task_struct *p,
return 0;
}
void thread_group_cputime(struct task_struct *tsk, struct task_cputime *times)
{
struct signal_struct *sig = tsk->signal;
struct task_struct *t;
times->utime = sig->utime;
times->stime = sig->stime;
times->sum_exec_runtime = sig->sum_sched_runtime;
rcu_read_lock();
/* make sure we can trust tsk->thread_group list */
if (!likely(pid_alive(tsk)))
goto out;
t = tsk;
do {
times->utime += t->utime;
times->stime += t->stime;
times->sum_exec_runtime += task_sched_runtime(t);
} while_each_thread(tsk, t);
out:
rcu_read_unlock();
}
static void update_gt_cputime(struct task_cputime *a, struct task_cputime *b)
{
if (b->utime > a->utime)

64
kernel/sched/auto_group.c
View File

@ -110,6 +110,9 @@ static inline struct autogroup *autogroup_create(void)
bool task_wants_autogroup(struct task_struct *p, struct task_group *tg)
{
if (!sysctl_sched_autogroup_enabled)
return false;
if (tg != &root_task_group)
return false;
@ -155,8 +158,11 @@ autogroup_move_group(struct task_struct *p, struct autogroup *ag)
/* Allocates GFP_KERNEL, cannot be called under any spinlock */
void sched_autogroup_create_attach(struct task_struct *p)
{
struct autogroup *ag = autogroup_create();
struct autogroup *ag;
if (!sysctl_sched_autogroup_enabled)
return;
ag = autogroup_create();
autogroup_move_group(p, ag);
/* drop extra reference added by autogroup_create() */
autogroup_kref_put(ag);
@ -172,11 +178,15 @@ EXPORT_SYMBOL(sched_autogroup_detach);
void sched_autogroup_fork(struct signal_struct *sig)
{
if (!sysctl_sched_autogroup_enabled)
return;
sig->autogroup = autogroup_task_get(current);
}
void sched_autogroup_exit(struct signal_struct *sig)
{
if (!sysctl_sched_autogroup_enabled)
return;
autogroup_kref_put(sig->autogroup);
}
@ -189,58 +199,6 @@ static int __init setup_autogroup(char *str)
__setup("noautogroup", setup_autogroup);
#ifdef CONFIG_PROC_FS
int proc_sched_autogroup_set_nice(struct task_struct *p, int nice)
{
static unsigned long next = INITIAL_JIFFIES;
struct autogroup *ag;
int err;
if (nice < -20 || nice > 19)
return -EINVAL;
err = security_task_setnice(current, nice);
if (err)
return err;
if (nice < 0 && !can_nice(current, nice))
return -EPERM;
/* this is a heavy operation taking global locks.. */
if (!capable(CAP_SYS_ADMIN) && time_before(jiffies, next))
return -EAGAIN;
next = HZ / 10 + jiffies;
ag = autogroup_task_get(p);
down_write(&ag->lock);
err = sched_group_set_shares(ag->tg, prio_to_weight[nice + 20]);
if (!err)
ag->nice = nice;
up_write(&ag->lock);
autogroup_kref_put(ag);
return err;
}
void proc_sched_autogroup_show_task(struct task_struct *p, struct seq_file *m)
{
struct autogroup *ag = autogroup_task_get(p);
if (!task_group_is_autogroup(ag->tg))
goto out;
down_read(&ag->lock);
seq_printf(m, "/autogroup-%ld nice %d\n", ag->id, ag->nice);
up_read(&ag->lock);
out:
autogroup_kref_put(ag);
}
#endif /* CONFIG_PROC_FS */
#ifdef CONFIG_SCHED_DEBUG
int autogroup_path(struct task_group *tg, char *buf, int buflen)
{

4
kernel/sched/auto_group.h
View File

@ -24,9 +24,7 @@ extern bool task_wants_autogroup(struct task_struct *p, struct task_group *tg);
static inline struct task_group *
autogroup_task_group(struct task_struct *p, struct task_group *tg)
{
int enabled = ACCESS_ONCE(sysctl_sched_autogroup_enabled);
if (enabled && task_wants_autogroup(p, tg))
if (task_wants_autogroup(p, tg))
return p->signal->autogroup->tg;
return tg;

98
kernel/sched/cputime.c
View File

@ -288,6 +288,34 @@ static __always_inline bool steal_account_process_tick(void)
return false;
}
/*
* Accumulate raw cputime values of dead tasks (sig->[us]time) and live
* tasks (sum on group iteration) belonging to @tsk's group.
*/
void thread_group_cputime(struct task_struct *tsk, struct task_cputime *times)
{
struct signal_struct *sig = tsk->signal;
struct task_struct *t;
times->utime = sig->utime;
times->stime = sig->stime;
times->sum_exec_runtime = sig->sum_sched_runtime;
rcu_read_lock();
/* make sure we can trust tsk->thread_group list */
if (!likely(pid_alive(tsk)))
goto out;
t = tsk;
do {
times->utime += t->utime;
times->stime += t->stime;
times->sum_exec_runtime += task_sched_runtime(t);
} while_each_thread(tsk, t);
out:
rcu_read_unlock();
}
#ifndef CONFIG_VIRT_CPU_ACCOUNTING
#ifdef CONFIG_IRQ_TIME_ACCOUNTING
@ -417,13 +445,13 @@ void account_idle_ticks(unsigned long ticks)
* Use precise platform statistics if available:
*/
#ifdef CONFIG_VIRT_CPU_ACCOUNTING
void task_times(struct task_struct *p, cputime_t *ut, cputime_t *st)
void task_cputime_adjusted(struct task_struct *p, cputime_t *ut, cputime_t *st)
{
*ut = p->utime;
*st = p->stime;
}
void thread_group_times(struct task_struct *p, cputime_t *ut, cputime_t *st)
void thread_group_cputime_adjusted(struct task_struct *p, cputime_t *ut, cputime_t *st)
{
struct task_cputime cputime;
@ -488,14 +516,30 @@ static cputime_t scale_utime(cputime_t utime, cputime_t rtime, cputime_t total)
return (__force cputime_t) temp;
}
void task_times(struct task_struct *p, cputime_t *ut, cputime_t *st)
/*
* Adjust tick based cputime random precision against scheduler
* runtime accounting.
*/
static void cputime_adjust(struct task_cputime *curr,
struct cputime *prev,
cputime_t *ut, cputime_t *st)
{
cputime_t rtime, utime = p->utime, total = utime + p->stime;
cputime_t rtime, utime, total;
utime = curr->utime;
total = utime + curr->stime;
/*
* Use CFS's precise accounting:
* Tick based cputime accounting depend on random scheduling
* timeslices of a task to be interrupted or not by the timer.
* Depending on these circumstances, the number of these interrupts
* may be over or under-optimistic, matching the real user and system
* cputime with a variable precision.
*
* Fix this by scaling these tick based values against the total
* runtime accounted by the CFS scheduler.
*/
rtime = nsecs_to_cputime(p->se.sum_exec_runtime);
rtime = nsecs_to_cputime(curr->sum_exec_runtime);
if (total)
utime = scale_utime(utime, rtime, total);
@ -503,38 +547,36 @@ void task_times(struct task_struct *p, cputime_t *ut, cputime_t *st)
utime = rtime;
/*
* Compare with previous values, to keep monotonicity:
* If the tick based count grows faster than the scheduler one,
* the result of the scaling may go backward.
* Let's enforce monotonicity.
*/
p->prev_utime = max(p->prev_utime, utime);
p->prev_stime = max(p->prev_stime, rtime - p->prev_utime);
prev->utime = max(prev->utime, utime);
prev->stime = max(prev->stime, rtime - prev->utime);
*ut = p->prev_utime;
*st = p->prev_stime;
*ut = prev->utime;
*st = prev->stime;
}
void task_cputime_adjusted(struct task_struct *p, cputime_t *ut, cputime_t *st)
{
struct task_cputime cputime = {
.utime = p->utime,
.stime = p->stime,
.sum_exec_runtime = p->se.sum_exec_runtime,
};
cputime_adjust(&cputime, &p->prev_cputime, ut, st);
}
/*
* Must be called with siglock held.
*/
void thread_group_times(struct task_struct *p, cputime_t *ut, cputime_t *st)
void thread_group_cputime_adjusted(struct task_struct *p, cputime_t *ut, cputime_t *st)
{
struct signal_struct *sig = p->signal;
struct task_cputime cputime;
cputime_t rtime, utime, total;
thread_group_cputime(p, &cputime);
total = cputime.utime + cputime.stime;
rtime = nsecs_to_cputime(cputime.sum_exec_runtime);
if (total)
utime = scale_utime(cputime.utime, rtime, total);
else
utime = rtime;
sig->prev_utime = max(sig->prev_utime, utime);
sig->prev_stime = max(sig->prev_stime, rtime - sig->prev_utime);
*ut = sig->prev_utime;
*st = sig->prev_stime;
cputime_adjust(&cputime, &p->signal->prev_cputime, ut, st);
}
#endif

2
kernel/sched/fair.c
View File

@ -3330,7 +3330,7 @@ static void check_preempt_wakeup(struct rq *rq, struct task_struct *p, int wake_
* Batch and idle tasks do not preempt non-idle tasks (their preemption
* is driven by the tick):
*/
if (unlikely(p->policy != SCHED_NORMAL))
if (unlikely(p->policy != SCHED_NORMAL) || !sched_feat(WAKEUP_PREEMPTION))
return;
find_matching_se(&se, &pse);

5
kernel/sched/features.h
View File

@ -31,6 +31,11 @@ SCHED_FEAT(LAST_BUDDY, true)
*/
SCHED_FEAT(CACHE_HOT_BUDDY, true)
/*
* Allow wakeup-time preemption of the current task:
*/
SCHED_FEAT(WAKEUP_PREEMPTION, true)
/*
* Use arch dependent cpu power functions
*/

6
kernel/sys.c
View File

@ -1046,7 +1046,7 @@ void do_sys_times(struct tms *tms)
cputime_t tgutime, tgstime, cutime, cstime;
spin_lock_irq(&current->sighand->siglock);
thread_group_times(current, &tgutime, &tgstime);
thread_group_cputime_adjusted(current, &tgutime, &tgstime);
cutime = current->signal->cutime;
cstime = current->signal->cstime;
spin_unlock_irq(&current->sighand->siglock);
@ -1704,7 +1704,7 @@ static void k_getrusage(struct task_struct *p, int who, struct rusage *r)
utime = stime = 0;
if (who == RUSAGE_THREAD) {
task_times(current, &utime, &stime);
task_cputime_adjusted(current, &utime, &stime);
accumulate_thread_rusage(p, r);
maxrss = p->signal->maxrss;
goto out;
@ -1730,7 +1730,7 @@ static void k_getrusage(struct task_struct *p, int who, struct rusage *r)
break;
case RUSAGE_SELF:
thread_group_times(p, &tgutime, &tgstime);
thread_group_cputime_adjusted(p, &tgutime, &tgstime);
utime += tgutime;
stime += tgstime;
r->ru_nvcsw += p->signal->nvcsw;

6
kernel/sysctl.c
View File

@ -367,10 +367,8 @@ static struct ctl_table kern_table[] = {
.procname = "sched_autogroup_enabled",
.data = &sysctl_sched_autogroup_enabled,
.maxlen = sizeof(unsigned int),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = &zero,
.extra2 = &one,
.mode = 0444,
.proc_handler = proc_dointvec,
},
#endif
#ifdef CONFIG_CFS_BANDWIDTH