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In the v6.12 scheduler development cycle we had 63 commits from 18 contributors:

Browse Source 
- Implement the SCHED_DEADLINE server infrastructure - Daniel Bristot de Oliveira's
    last major contribution to the kernel:
 
      "SCHED_DEADLINE servers can help fixing starvation issues of low priority
      tasks (e.g., SCHED_OTHER) when higher priority tasks monopolize CPU
      cycles. Today we have RT Throttling; DEADLINE servers should be able to
      replace and improve that."
 
      (Daniel Bristot de Oliveira, Peter Zijlstra, Joel Fernandes,
       Youssef Esmat, Huang Shijie)
 
  - Preparatory changes for sched_ext integration:
 
      - Use set_next_task(.first) where required
      - Fix up set_next_task() implementations
      - Clean up DL server vs. core sched
      - Split up put_prev_task_balance()
      - Rework pick_next_task()
      - Combine the last put_prev_task() and the first set_next_task()
      - Rework dl_server
      - Add put_prev_task(.next)
 
       (Peter Zijlstra, with a fix by Tejun Heo)
 
  - Complete the EEVDF transition and refine EEVDF scheduling:
 
      - Implement delayed dequeue
      - Allow shorter slices to wakeup-preempt
      - Use sched_attr::sched_runtime to set request/slice suggestion
      - Document the new feature flags
      - Remove unused and duplicate-functionality fields
      - Simplify & unify pick_next_task_fair()
      - Misc debuggability enhancements
 
       (Peter Zijlstra, with fixes/cleanups by Dietmar Eggemann,
        Valentin Schneider and Chuyi Zhou)
 
  - Initialize the vruntime of a new task when it is first enqueued,
    resulting in significant decrease in latency of newly woken tasks.
    (Zhang Qiao)
 
  - Introduce SM_IDLE and an idle re-entry fast-path in __schedule()
    (K Prateek Nayak, Peter Zijlstra)
 
  - Clean up and clarify the usage of Clean up usage of rt_task()
    (Qais Yousef)
 
  - Preempt SCHED_IDLE entities in strict cgroup hierarchies
    (Tianchen Ding)
 
  - Clarify the documentation of time units for deadline scheduler
    parameters. (Christian Loehle)
 
  - Remove the HZ_BW chicken-bit feature flag introduced a year ago,
    the original change seems to be working fine.
    (Phil Auld)
 
  - Misc fixes and cleanups (Chen Yu, Dan Carpenter, Huang Shijie,
    Peilin He, Qais Yousefm and Vincent Guittot)
 
 Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'sched-core-2024-09-19' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull scheduler updates from Ingo Molnar:

 - Implement the SCHED_DEADLINE server infrastructure - Daniel Bristot
   de Oliveira's last major contribution to the kernel:

     "SCHED_DEADLINE servers can help fixing starvation issues of low
      priority tasks (e.g., SCHED_OTHER) when higher priority tasks
      monopolize CPU cycles. Today we have RT Throttling; DEADLINE
      servers should be able to replace and improve that."

   (Daniel Bristot de Oliveira, Peter Zijlstra, Joel Fernandes, Youssef
   Esmat, Huang Shijie)

 - Preparatory changes for sched_ext integration:
     - Use set_next_task(.first) where required
     - Fix up set_next_task() implementations
     - Clean up DL server vs. core sched
     - Split up put_prev_task_balance()
     - Rework pick_next_task()
     - Combine the last put_prev_task() and the first set_next_task()
     - Rework dl_server
     - Add put_prev_task(.next)

   (Peter Zijlstra, with a fix by Tejun Heo)

 - Complete the EEVDF transition and refine EEVDF scheduling:
     - Implement delayed dequeue
     - Allow shorter slices to wakeup-preempt
     - Use sched_attr::sched_runtime to set request/slice suggestion
     - Document the new feature flags
     - Remove unused and duplicate-functionality fields
     - Simplify & unify pick_next_task_fair()
     - Misc debuggability enhancements

   (Peter Zijlstra, with fixes/cleanups by Dietmar Eggemann, Valentin
   Schneider and Chuyi Zhou)

 - Initialize the vruntime of a new task when it is first enqueued,
   resulting in significant decrease in latency of newly woken tasks
   (Zhang Qiao)

 - Introduce SM_IDLE and an idle re-entry fast-path in __schedule()
   (K Prateek Nayak, Peter Zijlstra)

 - Clean up and clarify the usage of Clean up usage of rt_task()
   (Qais Yousef)

 - Preempt SCHED_IDLE entities in strict cgroup hierarchies
   (Tianchen Ding)

 - Clarify the documentation of time units for deadline scheduler
   parameters (Christian Loehle)

 - Remove the HZ_BW chicken-bit feature flag introduced a year ago,
   the original change seems to be working fine (Phil Auld)

 - Misc fixes and cleanups (Chen Yu, Dan Carpenter, Huang Shijie,
   Peilin He, Qais Yousefm and Vincent Guittot)

* tag 'sched-core-2024-09-19' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (64 commits)
  sched/cpufreq: Use NSEC_PER_MSEC for deadline task
  cpufreq/cppc: Use NSEC_PER_MSEC for deadline task
  sched/deadline: Clarify nanoseconds in uapi
  sched/deadline: Convert schedtool example to chrt
  sched/debug: Fix the runnable tasks output
  sched: Fix sched_delayed vs sched_core
  kernel/sched: Fix util_est accounting for DELAY_DEQUEUE
  kthread: Fix task state in kthread worker if being frozen
  sched/pelt: Use rq_clock_task() for hw_pressure
  sched/fair: Move effective_cpu_util() and effective_cpu_util() in fair.c
  sched/core: Introduce SM_IDLE and an idle re-entry fast-path in __schedule()
  sched: Add put_prev_task(.next)
  sched: Rework dl_server
  sched: Combine the last put_prev_task() and the first set_next_task()
  sched: Rework pick_next_task()
  sched: Split up put_prev_task_balance()
  sched: Clean up DL server vs core sched
  sched: Fixup set_next_task() implementations
  sched: Use set_next_task(.first) where required
  sched/fair: Properly deactivate sched_delayed task upon class change
  ...
This commit is contained in:
Linus Torvalds 2024-09-19 15:55:58 +02:00
commit 2004cef11e
32 changed files with 1695 additions and 747 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

14
Documentation/scheduler/sched-deadline.rst
View File

@ -749,21 +749,19 @@ Appendix A. Test suite
of the command line options. Please refer to rt-app documentation for more
details (`<rt-app-sources>/doc/*.json`).
The second testing application is a modification of schedtool, called
schedtool-dl, which can be used to setup SCHED_DEADLINE parameters for a
certain pid/application. schedtool-dl is available at:
https://github.com/scheduler-tools/schedtool-dl.git.
The second testing application is done using chrt which has support
for SCHED_DEADLINE.
The usage is straightforward::
# schedtool -E -t 10000000:100000000 -e ./my_cpuhog_app
# chrt -d -T 10000000 -D 100000000 0 ./my_cpuhog_app
With this, my_cpuhog_app is put to run inside a SCHED_DEADLINE reservation
of 10ms every 100ms (note that parameters are expressed in microseconds).
You can also use schedtool to create a reservation for an already running
of 10ms every 100ms (note that parameters are expressed in nanoseconds).
You can also use chrt to create a reservation for an already running
application, given that you know its pid::
# schedtool -E -t 10000000:100000000 my_app_pid
# chrt -d -T 10000000 -D 100000000 -p 0 my_app_pid
Appendix B. Minimal main()
==========================

6
drivers/cpufreq/cppc_cpufreq.c
View File

@ -224,9 +224,9 @@ static void __init cppc_freq_invariance_init(void)
* Fake (unused) bandwidth; workaround to "fix"
* priority inheritance.
*/
.sched_runtime = 1000000,
.sched_deadline = 10000000,
.sched_period = 10000000,
.sched_runtime = NSEC_PER_MSEC,
.sched_deadline = 10 * NSEC_PER_MSEC,
.sched_period = 10 * NSEC_PER_MSEC,
};
int ret;

2
fs/bcachefs/six.c
View File

@ -335,7 +335,7 @@ static inline bool six_owner_running(struct six_lock *lock)
*/
rcu_read_lock();
struct task_struct *owner = READ_ONCE(lock->owner);
bool ret = owner ? owner_on_cpu(owner) : !rt_task(current);
bool ret = owner ? owner_on_cpu(owner) : !rt_or_dl_task(current);
rcu_read_unlock();
return ret;

2
fs/proc/base.c
View File

@ -2626,7 +2626,7 @@ static ssize_t timerslack_ns_write(struct file *file, const char __user *buf,
}
task_lock(p);
if (task_is_realtime(p))
if (rt_or_dl_task_policy(p))
slack_ns = 0;
else if (slack_ns == 0)
slack_ns = p->default_timer_slack_ns;

2
include/linux/ioprio.h
View File

@ -40,7 +40,7 @@ static inline int task_nice_ioclass(struct task_struct *task)
{
if (task->policy == SCHED_IDLE)
return IOPRIO_CLASS_IDLE;
else if (task_is_realtime(task))
else if (rt_or_dl_task_policy(task))
return IOPRIO_CLASS_RT;
else
return IOPRIO_CLASS_BE;

28
include/linux/sched.h
View File

@ -149,8 +149,9 @@ struct user_event_mm;
* Special states are those that do not use the normal wait-loop pattern. See
* the comment with set_special_state().
*/
#define is_special_task_state(state) \
((state) & (__TASK_STOPPED | __TASK_TRACED | TASK_PARKED | TASK_DEAD))
#define is_special_task_state(state) \
((state) & (__TASK_STOPPED | __TASK_TRACED | TASK_PARKED | \
TASK_DEAD | TASK_FROZEN))
#ifdef CONFIG_DEBUG_ATOMIC_SLEEP
# define debug_normal_state_change(state_value) \
@ -541,9 +542,14 @@ struct sched_entity {
struct rb_node run_node;
u64 deadline;
u64 min_vruntime;
u64 min_slice;
struct list_head group_node;
unsigned int on_rq;
unsigned char on_rq;
unsigned char sched_delayed;
unsigned char rel_deadline;
unsigned char custom_slice;
/* hole */
u64 exec_start;
u64 sum_exec_runtime;
@ -639,12 +645,26 @@ struct sched_dl_entity {
*
* @dl_overrun tells if the task asked to be informed about runtime
* overruns.
*
* @dl_server tells if this is a server entity.
*
* @dl_defer tells if this is a deferred or regular server. For
* now only defer server exists.
*
* @dl_defer_armed tells if the deferrable server is waiting
* for the replenishment timer to activate it.
*
* @dl_defer_running tells if the deferrable server is actually
* running, skipping the defer phase.
*/
unsigned int dl_throttled : 1;
unsigned int dl_yielded : 1;
unsigned int dl_non_contending : 1;
unsigned int dl_overrun : 1;
unsigned int dl_server : 1;
unsigned int dl_defer : 1;
unsigned int dl_defer_armed : 1;
unsigned int dl_defer_running : 1;
/*
* Bandwidth enforcement timer. Each -deadline task has its
@ -672,7 +692,7 @@ struct sched_dl_entity {
*/
struct rq *rq;
dl_server_has_tasks_f server_has_tasks;
dl_server_pick_f server_pick;
dl_server_pick_f server_pick_task;
#ifdef CONFIG_RT_MUTEXES
/*

14
include/linux/sched/deadline.h
View File

@ -10,16 +10,16 @@
#include <linux/sched.h>
#define MAX_DL_PRIO 0
static inline int dl_prio(int prio)
static inline bool dl_prio(int prio)
{
if (unlikely(prio < MAX_DL_PRIO))
return 1;
return 0;
return unlikely(prio < MAX_DL_PRIO);
}
static inline int dl_task(struct task_struct *p)
/*
* Returns true if a task has a priority that belongs to DL class. PI-boosted
* tasks will return true. Use dl_policy() to ignore PI-boosted tasks.
*/
static inline bool dl_task(struct task_struct *p)
{
return dl_prio(p->prio);
}

1
include/linux/sched/prio.h
View File

@ -14,6 +14,7 @@
*/
#define MAX_RT_PRIO 100
#define MAX_DL_PRIO 0
#define MAX_PRIO (MAX_RT_PRIO + NICE_WIDTH)
#define DEFAULT_PRIO (MAX_RT_PRIO + NICE_WIDTH / 2)

33
include/linux/sched/rt.h
View File

@ -6,19 +6,40 @@
struct task_struct;
static inline int rt_prio(int prio)
static inline bool rt_prio(int prio)
{
if (unlikely(prio < MAX_RT_PRIO))
return 1;
return 0;
return unlikely(prio < MAX_RT_PRIO && prio >= MAX_DL_PRIO);
}
static inline int rt_task(struct task_struct *p)
static inline bool rt_or_dl_prio(int prio)
{
return unlikely(prio < MAX_RT_PRIO);
}
/*
* Returns true if a task has a priority that belongs to RT class. PI-boosted
* tasks will return true. Use rt_policy() to ignore PI-boosted tasks.
*/
static inline bool rt_task(struct task_struct *p)
{
return rt_prio(p->prio);
}
static inline bool task_is_realtime(struct task_struct *tsk)
/*
* Returns true if a task has a priority that belongs to RT or DL classes.
* PI-boosted tasks will return true. Use rt_or_dl_task_policy() to ignore
* PI-boosted tasks.
*/
static inline bool rt_or_dl_task(struct task_struct *p)
{
return rt_or_dl_prio(p->prio);
}
/*
* Returns true if a task has a policy that belongs to RT or DL classes.
* PI-boosted tasks will return false.
*/
static inline bool rt_or_dl_task_policy(struct task_struct *tsk)
{
int policy = tsk->policy;

6
include/uapi/linux/sched/types.h
View File

@ -58,9 +58,9 @@
*
* This is reflected by the following fields of the sched_attr structure:
*
* @sched_deadline representative of the task's deadline
* @sched_runtime representative of the task's runtime
* @sched_period representative of the task's period
* @sched_deadline representative of the task's deadline in nanoseconds
* @sched_runtime representative of the task's runtime in nanoseconds
* @sched_period representative of the task's period in nanoseconds
*
* Given this task model, there are a multiplicity of scheduling algorithms
* and policies, that can be used to ensure all the tasks will make their

2
kernel/freezer.c
View File

@ -72,7 +72,7 @@ bool __refrigerator(bool check_kthr_stop)
bool freeze;
raw_spin_lock_irq(&current->pi_lock);
set_current_state(TASK_FROZEN);
WRITE_ONCE(current->__state, TASK_FROZEN);
/* unstale saved_state so that __thaw_task() will wake us up */
current->saved_state = TASK_RUNNING;
raw_spin_unlock_irq(&current->pi_lock);

10
kernel/kthread.c
View File

@ -845,8 +845,16 @@ int kthread_worker_fn(void *worker_ptr)
* event only cares about the address.
*/
trace_sched_kthread_work_execute_end(work, func);
} else if (!freezing(current))
} else if (!freezing(current)) {
schedule();
} else {
/*
* Handle the case where the current remains
* TASK_INTERRUPTIBLE. try_to_freeze() expects
* the current to be TASK_RUNNING.
*/
__set_current_state(TASK_RUNNING);
}
try_to_freeze();
cond_resched();

4
kernel/locking/rtmutex.c
View File

@ -347,7 +347,7 @@ static __always_inline int __waiter_prio(struct task_struct *task)
{
int prio = task->prio;
if (!rt_prio(prio))
if (!rt_or_dl_prio(prio))
return DEFAULT_PRIO;
return prio;
@ -435,7 +435,7 @@ static inline bool rt_mutex_steal(struct rt_mutex_waiter *waiter,
* Note that RT tasks are excluded from same priority (lateral)
* steals to prevent the introduction of an unbounded latency.
*/
if (rt_prio(waiter->tree.prio) || dl_prio(waiter->tree.prio))
if (rt_or_dl_prio(waiter->tree.prio))
return false;
return rt_waiter_node_equal(&waiter->tree, &top_waiter->tree);

4
kernel/locking/rwsem.c
View File

@ -631,7 +631,7 @@ static inline bool rwsem_try_write_lock(struct rw_semaphore *sem,
* if it is an RT task or wait in the wait queue
* for too long.
*/
if (has_handoff || (!rt_task(waiter->task) &&
if (has_handoff || (!rt_or_dl_task(waiter->task) &&
!time_after(jiffies, waiter->timeout)))
return false;
@ -914,7 +914,7 @@ static bool rwsem_optimistic_spin(struct rw_semaphore *sem)
if (owner_state != OWNER_WRITER) {
if (need_resched())
break;
if (rt_task(current) &&
if (rt_or_dl_task(current) &&
(prev_owner_state != OWNER_WRITER))
break;
}

2
kernel/locking/ww_mutex.h
View File

@ -237,7 +237,7 @@ __ww_ctx_less(struct ww_acquire_ctx *a, struct ww_acquire_ctx *b)
int a_prio = a->task->prio;
int b_prio = b->task->prio;
if (rt_prio(a_prio) || rt_prio(b_prio)) {
if (rt_or_dl_prio(a_prio) || rt_or_dl_prio(b_prio)) {
if (a_prio > b_prio)
return true;

248
kernel/sched/core.c
View File

@ -163,7 +163,10 @@ static inline int __task_prio(const struct task_struct *p)
if (p->sched_class == &stop_sched_class) /* trumps deadline */
return -2;
if (rt_prio(p->prio)) /* includes deadline */
if (p->dl_server)
return -1; /* deadline */
if (rt_or_dl_prio(p->prio))
return p->prio; /* [-1, 99] */
if (p->sched_class == &idle_sched_class)
@ -192,8 +195,24 @@ static inline bool prio_less(const struct task_struct *a,
if (-pb < -pa)
return false;
if (pa == -1) /* dl_prio() doesn't work because of stop_class above */
return !dl_time_before(a->dl.deadline, b->dl.deadline);
if (pa == -1) { /* dl_prio() doesn't work because of stop_class above */
const struct sched_dl_entity *a_dl, *b_dl;
a_dl = &a->dl;
/*
* Since,'a' and 'b' can be CFS tasks served by DL server,
* __task_prio() can return -1 (for DL) even for those. In that
* case, get to the dl_server's DL entity.
*/
if (a->dl_server)
a_dl = a->dl_server;
b_dl = &b->dl;
if (b->dl_server)
b_dl = b->dl_server;
return !dl_time_before(a_dl->deadline, b_dl->deadline);
}
if (pa == MAX_RT_PRIO + MAX_NICE) /* fair */
return cfs_prio_less(a, b, in_fi);
@ -240,6 +259,9 @@ static inline int rb_sched_core_cmp(const void *key, const struct rb_node *node)
void sched_core_enqueue(struct rq *rq, struct task_struct *p)
{
if (p->se.sched_delayed)
return;
rq->core->core_task_seq++;
if (!p->core_cookie)
@ -250,6 +272,9 @@ void sched_core_enqueue(struct rq *rq, struct task_struct *p)
void sched_core_dequeue(struct rq *rq, struct task_struct *p, int flags)
{
if (p->se.sched_delayed)
return;
rq->core->core_task_seq++;
if (sched_core_enqueued(p)) {
@ -1269,7 +1294,7 @@ bool sched_can_stop_tick(struct rq *rq)
* dequeued by migrating while the constrained task continues to run.
* E.g. going from 2->1 without going through pick_next_task().
*/
if (sched_feat(HZ_BW) && __need_bw_check(rq, rq->curr)) {
if (__need_bw_check(rq, rq->curr)) {
if (cfs_task_bw_constrained(rq->curr))
return false;
}
@ -1672,6 +1697,9 @@ static inline void uclamp_rq_inc(struct rq *rq, struct task_struct *p)
if (unlikely(!p->sched_class->uclamp_enabled))
return;
if (p->se.sched_delayed)
return;
for_each_clamp_id(clamp_id)
uclamp_rq_inc_id(rq, p, clamp_id);
@ -1696,6 +1724,9 @@ static inline void uclamp_rq_dec(struct rq *rq, struct task_struct *p)
if (unlikely(!p->sched_class->uclamp_enabled))
return;
if (p->se.sched_delayed)
return;
for_each_clamp_id(clamp_id)
uclamp_rq_dec_id(rq, p, clamp_id);
}
@ -1975,14 +2006,21 @@ void enqueue_task(struct rq *rq, struct task_struct *p, int flags)
psi_enqueue(p, (flags & ENQUEUE_WAKEUP) && !(flags & ENQUEUE_MIGRATED));
}
uclamp_rq_inc(rq, p);
p->sched_class->enqueue_task(rq, p, flags);
/*
* Must be after ->enqueue_task() because ENQUEUE_DELAYED can clear
* ->sched_delayed.
*/
uclamp_rq_inc(rq, p);
if (sched_core_enabled(rq))
sched_core_enqueue(rq, p);
}
void dequeue_task(struct rq *rq, struct task_struct *p, int flags)
/*
* Must only return false when DEQUEUE_SLEEP.
*/
inline bool dequeue_task(struct rq *rq, struct task_struct *p, int flags)
{
if (sched_core_enabled(rq))
sched_core_dequeue(rq, p, flags);
@ -1995,8 +2033,12 @@ void dequeue_task(struct rq *rq, struct task_struct *p, int flags)
psi_dequeue(p, flags & DEQUEUE_SLEEP);
}
/*
* Must be before ->dequeue_task() because ->dequeue_task() can 'fail'
* and mark the task ->sched_delayed.
*/
uclamp_rq_dec(rq, p);
p->sched_class->dequeue_task(rq, p, flags);
return p->sched_class->dequeue_task(rq, p, flags);
}
void activate_task(struct rq *rq, struct task_struct *p, int flags)
@ -2014,12 +2056,25 @@ void activate_task(struct rq *rq, struct task_struct *p, int flags)
void deactivate_task(struct rq *rq, struct task_struct *p, int flags)
{
WRITE_ONCE(p->on_rq, (flags & DEQUEUE_SLEEP) ? 0 : TASK_ON_RQ_MIGRATING);
SCHED_WARN_ON(flags & DEQUEUE_SLEEP);
WRITE_ONCE(p->on_rq, TASK_ON_RQ_MIGRATING);
ASSERT_EXCLUSIVE_WRITER(p->on_rq);
/*
* Code explicitly relies on TASK_ON_RQ_MIGRATING begin set *before*
* dequeue_task() and cleared *after* enqueue_task().
*/
dequeue_task(rq, p, flags);
}
static void block_task(struct rq *rq, struct task_struct *p, int flags)
{
if (dequeue_task(rq, p, DEQUEUE_SLEEP | flags))
__block_task(rq, p);
}
/**
* task_curr - is this task currently executing on a CPU?
* @p: the task in question.
@ -2233,6 +2288,12 @@ void migrate_disable(void)
struct task_struct *p = current;
if (p->migration_disabled) {
#ifdef CONFIG_DEBUG_PREEMPT
/*
*Warn about overflow half-way through the range.
*/
WARN_ON_ONCE((s16)p->migration_disabled < 0);
#endif
p->migration_disabled++;
return;
}
@ -2251,14 +2312,20 @@ void migrate_enable(void)
.flags = SCA_MIGRATE_ENABLE,
};
#ifdef CONFIG_DEBUG_PREEMPT
/*
* Check both overflow from migrate_disable() and superfluous
* migrate_enable().
*/
if (WARN_ON_ONCE((s16)p->migration_disabled <= 0))
return;
#endif
if (p->migration_disabled > 1) {
p->migration_disabled--;
return;
}
if (WARN_ON_ONCE(!p->migration_disabled))
return;
/*
* Ensure stop_task runs either before or after this, and that
* __set_cpus_allowed_ptr(SCA_MIGRATE_ENABLE) doesn't schedule().
@ -3607,8 +3674,6 @@ ttwu_do_activate(struct rq *rq, struct task_struct *p, int wake_flags,
rq->idle_stamp = 0;
}
#endif
p->dl_server = NULL;
}
/*
@ -3644,12 +3709,14 @@ static int ttwu_runnable(struct task_struct *p, int wake_flags)
rq = __task_rq_lock(p, &rf);
if (task_on_rq_queued(p)) {
update_rq_clock(rq);
if (p->se.sched_delayed)
enqueue_task(rq, p, ENQUEUE_NOCLOCK | ENQUEUE_DELAYED);
if (!task_on_cpu(rq, p)) {
/*
* When on_rq && !on_cpu the task is preempted, see if
* it should preempt the task that is current now.
*/
update_rq_clock(rq);
wakeup_preempt(rq, p, wake_flags);
}
ttwu_do_wakeup(p);
@ -4029,11 +4096,16 @@ int try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags)
* case the whole 'p->on_rq && ttwu_runnable()' case below
* without taking any locks.
*
* Specifically, given current runs ttwu() we must be before
* schedule()'s block_task(), as such this must not observe
* sched_delayed.
*
* In particular:
* - we rely on Program-Order guarantees for all the ordering,
* - we're serialized against set_special_state() by virtue of
* it disabling IRQs (this allows not taking ->pi_lock).
*/
SCHED_WARN_ON(p->se.sched_delayed);
if (!ttwu_state_match(p, state, &success))
goto out;
@ -4322,9 +4394,11 @@ static void __sched_fork(unsigned long clone_flags, struct task_struct *p)
p->se.nr_migrations = 0;
p->se.vruntime = 0;
p->se.vlag = 0;
p->se.slice = sysctl_sched_base_slice;
INIT_LIST_HEAD(&p->se.group_node);
/* A delayed task cannot be in clone(). */
SCHED_WARN_ON(p->se.sched_delayed);
#ifdef CONFIG_FAIR_GROUP_SCHED
p->se.cfs_rq = NULL;
#endif
@ -4572,6 +4646,8 @@ int sched_fork(unsigned long clone_flags, struct task_struct *p)
p->prio = p->normal_prio = p->static_prio;
set_load_weight(p, false);
p->se.custom_slice = 0;
p->se.slice = sysctl_sched_base_slice;
/*
* We don't need the reset flag anymore after the fork. It has
@ -4686,7 +4762,7 @@ void wake_up_new_task(struct task_struct *p)
update_rq_clock(rq);
post_init_entity_util_avg(p);
activate_task(rq, p, ENQUEUE_NOCLOCK);
activate_task(rq, p, ENQUEUE_NOCLOCK | ENQUEUE_INITIAL);
trace_sched_wakeup_new(p);
wakeup_preempt(rq, p, WF_FORK);
#ifdef CONFIG_SMP
@ -5769,8 +5845,8 @@ static inline void schedule_debug(struct task_struct *prev, bool preempt)
schedstat_inc(this_rq()->sched_count);
}
static void put_prev_task_balance(struct rq *rq, struct task_struct *prev,
struct rq_flags *rf)
static void prev_balance(struct rq *rq, struct task_struct *prev,
struct rq_flags *rf)
{
#ifdef CONFIG_SMP
const struct sched_class *class;
@ -5787,8 +5863,6 @@ static void put_prev_task_balance(struct rq *rq, struct task_struct *prev,
break;
}
#endif
put_prev_task(rq, prev);
}
/*
@ -5800,6 +5874,8 @@ __pick_next_task(struct rq *rq, struct task_struct *prev, struct rq_flags *rf)
const struct sched_class *class;
struct task_struct *p;
rq->dl_server = NULL;
/*
* Optimization: we know that if all tasks are in the fair class we can
* call that function directly, but only if the @prev task wasn't of a
@ -5815,35 +5891,28 @@ __pick_next_task(struct rq *rq, struct task_struct *prev, struct rq_flags *rf)
/* Assume the next prioritized class is idle_sched_class */
if (!p) {
put_prev_task(rq, prev);
p = pick_next_task_idle(rq);
p = pick_task_idle(rq);
put_prev_set_next_task(rq, prev, p);
}
/*
* This is the fast path; it cannot be a DL server pick;
* therefore even if @p == @prev, ->dl_server must be NULL.
*/
if (p->dl_server)
p->dl_server = NULL;
return p;
}
restart:
put_prev_task_balance(rq, prev, rf);
/*
* We've updated @prev and no longer need the server link, clear it.
* Must be done before ->pick_next_task() because that can (re)set
* ->dl_server.
*/
if (prev->dl_server)
prev->dl_server = NULL;
prev_balance(rq, prev, rf);
for_each_class(class) {
p = class->pick_next_task(rq);
if (p)
return p;
if (class->pick_next_task) {
p = class->pick_next_task(rq, prev);
if (p)
return p;
} else {
p = class->pick_task(rq);
if (p) {
put_prev_set_next_task(rq, prev, p);
return p;
}
}
}
BUG(); /* The idle class should always have a runnable task. */
@ -5873,6 +5942,8 @@ static inline struct task_struct *pick_task(struct rq *rq)
const struct sched_class *class;
struct task_struct *p;
rq->dl_server = NULL;
for_each_class(class) {
p = class->pick_task(rq);
if (p)
@ -5911,6 +5982,7 @@ pick_next_task(struct rq *rq, struct task_struct *prev, struct rq_flags *rf)
* another cpu during offline.
*/
rq->core_pick = NULL;
rq->core_dl_server = NULL;
return __pick_next_task(rq, prev, rf);
}
@ -5929,16 +6001,13 @@ pick_next_task(struct rq *rq, struct task_struct *prev, struct rq_flags *rf)
WRITE_ONCE(rq->core_sched_seq, rq->core->core_pick_seq);
next = rq->core_pick;
if (next != prev) {
put_prev_task(rq, prev);
set_next_task(rq, next);
}
rq->dl_server = rq->core_dl_server;
rq->core_pick = NULL;
goto out;
rq->core_dl_server = NULL;
goto out_set_next;
}
put_prev_task_balance(rq, prev, rf);
prev_balance(rq, prev, rf);
smt_mask = cpu_smt_mask(cpu);
need_sync = !!rq->core->core_cookie;
@ -5979,6 +6048,7 @@ pick_next_task(struct rq *rq, struct task_struct *prev, struct rq_flags *rf)
next = pick_task(rq);
if (!next->core_cookie) {
rq->core_pick = NULL;
rq->core_dl_server = NULL;
/*
* For robustness, update the min_vruntime_fi for
* unconstrained picks as well.
@ -6006,7 +6076,9 @@ pick_next_task(struct rq *rq, struct task_struct *prev, struct rq_flags *rf)
if (i != cpu && (rq_i != rq->core || !core_clock_updated))
update_rq_clock(rq_i);
p = rq_i->core_pick = pick_task(rq_i);
rq_i->core_pick = p = pick_task(rq_i);
rq_i->core_dl_server = rq_i->dl_server;
if (!max || prio_less(max, p, fi_before))
max = p;
}
@ -6030,6 +6102,7 @@ pick_next_task(struct rq *rq, struct task_struct *prev, struct rq_flags *rf)
}
rq_i->core_pick = p;
rq_i->core_dl_server = NULL;
if (p == rq_i->idle) {
if (rq_i->nr_running) {
@ -6090,6 +6163,7 @@ pick_next_task(struct rq *rq, struct task_struct *prev, struct rq_flags *rf)
if (i == cpu) {
rq_i->core_pick = NULL;
rq_i->core_dl_server = NULL;
continue;
}
@ -6098,6 +6172,7 @@ pick_next_task(struct rq *rq, struct task_struct *prev, struct rq_flags *rf)
if (rq_i->curr == rq_i->core_pick) {
rq_i->core_pick = NULL;
rq_i->core_dl_server = NULL;
continue;
}
@ -6105,8 +6180,7 @@ pick_next_task(struct rq *rq, struct task_struct *prev, struct rq_flags *rf)
}
out_set_next:
set_next_task(rq, next);
out:
put_prev_set_next_task(rq, prev, next);
if (rq->core->core_forceidle_count && next == rq->idle)
queue_core_balance(rq);
@ -6342,19 +6416,12 @@ pick_next_task(struct rq *rq, struct task_struct *prev, struct rq_flags *rf)
* Constants for the sched_mode argument of __schedule().
*
* The mode argument allows RT enabled kernels to differentiate a
* preemption from blocking on an 'sleeping' spin/rwlock. Note that
* SM_MASK_PREEMPT for !RT has all bits set, which allows the compiler to
* optimize the AND operation out and just check for zero.
* preemption from blocking on an 'sleeping' spin/rwlock.
*/
#define SM_NONE 0x0
#define SM_PREEMPT 0x1
#define SM_RTLOCK_WAIT 0x2
#ifndef CONFIG_PREEMPT_RT
# define SM_MASK_PREEMPT (~0U)
#else
# define SM_MASK_PREEMPT SM_PREEMPT
#endif
#define SM_IDLE (-1)
#define SM_NONE 0
#define SM_PREEMPT 1
#define SM_RTLOCK_WAIT 2
/*
* __schedule() is the main scheduler function.
@ -6395,9 +6462,14 @@ pick_next_task(struct rq *rq, struct task_struct *prev, struct rq_flags *rf)
*
* WARNING: must be called with preemption disabled!
*/
static void __sched notrace __schedule(unsigned int sched_mode)
static void __sched notrace __schedule(int sched_mode)
{
struct task_struct *prev, *next;
/*
* On PREEMPT_RT kernel, SM_RTLOCK_WAIT is noted
* as a preemption by schedule_debug() and RCU.
*/
bool preempt = sched_mode > SM_NONE;
unsigned long *switch_count;
unsigned long prev_state;
struct rq_flags rf;
@ -6408,13 +6480,13 @@ static void __sched notrace __schedule(unsigned int sched_mode)
rq = cpu_rq(cpu);
prev = rq->curr;
schedule_debug(prev, !!sched_mode);
schedule_debug(prev, preempt);
if (sched_feat(HRTICK) || sched_feat(HRTICK_DL))
hrtick_clear(rq);
local_irq_disable();
rcu_note_context_switch(!!sched_mode);
rcu_note_context_switch(preempt);
/*
* Make sure that signal_pending_state()->signal_pending() below
@ -6443,22 +6515,32 @@ static void __sched notrace __schedule(unsigned int sched_mode)
switch_count = &prev->nivcsw;
/* Task state changes only considers SM_PREEMPT as preemption */
preempt = sched_mode == SM_PREEMPT;
/*
* We must load prev->state once (task_struct::state is volatile), such
* that we form a control dependency vs deactivate_task() below.
*/
prev_state = READ_ONCE(prev->__state);
if (!(sched_mode & SM_MASK_PREEMPT) && prev_state) {
if (sched_mode == SM_IDLE) {
if (!rq->nr_running) {
next = prev;
goto picked;
}
} else if (!preempt && prev_state) {
if (signal_pending_state(prev_state, prev)) {
WRITE_ONCE(prev->__state, TASK_RUNNING);
} else {
int flags = DEQUEUE_NOCLOCK;
prev->sched_contributes_to_load =
(prev_state & TASK_UNINTERRUPTIBLE) &&
!(prev_state & TASK_NOLOAD) &&
!(prev_state & TASK_FROZEN);
if (prev->sched_contributes_to_load)
rq->nr_uninterruptible++;
if (unlikely(is_special_task_state(prev_state)))
flags |= DEQUEUE_SPECIAL;
/*
* __schedule() ttwu()
@ -6471,17 +6553,13 @@ static void __sched notrace __schedule(unsigned int sched_mode)
*
* After this, schedule() must not care about p->state any more.
*/
deactivate_task(rq, prev, DEQUEUE_SLEEP | DEQUEUE_NOCLOCK);
if (prev->in_iowait) {
atomic_inc(&rq->nr_iowait);
delayacct_blkio_start();
}
block_task(rq, prev, flags);
}
switch_count = &prev->nvcsw;
}
next = pick_next_task(rq, prev, &rf);
picked:
clear_tsk_need_resched(prev);
clear_preempt_need_resched();
#ifdef CONFIG_SCHED_DEBUG
@ -6523,7 +6601,7 @@ static void __sched notrace __schedule(unsigned int sched_mode)
psi_account_irqtime(rq, prev, next);
psi_sched_switch(prev, next, !task_on_rq_queued(prev));
trace_sched_switch(sched_mode & SM_MASK_PREEMPT, prev, next, prev_state);
trace_sched_switch(preempt, prev, next, prev_state);
/* Also unlocks the rq: */
rq = context_switch(rq, prev, next, &rf);
@ -6599,7 +6677,7 @@ static void sched_update_worker(struct task_struct *tsk)
}
}
static __always_inline void __schedule_loop(unsigned int sched_mode)
static __always_inline void __schedule_loop(int sched_mode)
{
do {
preempt_disable();
@ -6644,7 +6722,7 @@ void __sched schedule_idle(void)
*/
WARN_ON_ONCE(current->__state);
do {
__schedule(SM_NONE);
__schedule(SM_IDLE);
} while (need_resched());
}
@ -8228,8 +8306,6 @@ void __init sched_init(void)
#endif /* CONFIG_RT_GROUP_SCHED */
}
init_rt_bandwidth(&def_rt_bandwidth, global_rt_period(), global_rt_runtime());
#ifdef CONFIG_SMP
init_defrootdomain();
#endif
@ -8284,8 +8360,13 @@ void __init sched_init(void)
init_tg_cfs_entry(&root_task_group, &rq->cfs, NULL, i, NULL);
#endif /* CONFIG_FAIR_GROUP_SCHED */
rq->rt.rt_runtime = def_rt_bandwidth.rt_runtime;
#ifdef CONFIG_RT_GROUP_SCHED
/*
* This is required for init cpu because rt.c:__enable_runtime()
* starts working after scheduler_running, which is not the case
* yet.
*/
rq->rt.rt_runtime = global_rt_runtime();
init_tg_rt_entry(&root_task_group, &rq->rt, NULL, i, NULL);
#endif
#ifdef CONFIG_SMP
@ -8317,10 +8398,12 @@ void __init sched_init(void)
#endif /* CONFIG_SMP */
hrtick_rq_init(rq);
atomic_set(&rq->nr_iowait, 0);
fair_server_init(rq);
#ifdef CONFIG_SCHED_CORE
rq->core = rq;
rq->core_pick = NULL;
rq->core_dl_server = NULL;
rq->core_enabled = 0;
rq->core_tree = RB_ROOT;
rq->core_forceidle_count = 0;
@ -8333,6 +8416,7 @@ void __init sched_init(void)
}
set_load_weight(&init_task, false);
init_task.se.slice = sysctl_sched_base_slice,
/*
* The boot idle thread does lazy MMU switching as well:
@ -8548,7 +8632,7 @@ void normalize_rt_tasks(void)
schedstat_set(p->stats.sleep_start, 0);
schedstat_set(p->stats.block_start, 0);
if (!dl_task(p) && !rt_task(p)) {
if (!rt_or_dl_task(p)) {
/*
* Renice negative nice level userspace
* tasks back to 0:

6
kernel/sched/cpufreq_schedutil.c
View File

@ -654,9 +654,9 @@ static int sugov_kthread_create(struct sugov_policy *sg_policy)
* Fake (unused) bandwidth; workaround to "fix"
* priority inheritance.
*/
.sched_runtime = 1000000,
.sched_deadline = 10000000,
.sched_period = 10000000,
.sched_runtime = NSEC_PER_MSEC,
.sched_deadline = 10 * NSEC_PER_MSEC,
.sched_period = 10 * NSEC_PER_MSEC,
};
struct cpufreq_policy *policy = sg_policy->policy;
int ret;

503
kernel/sched/deadline.c
View File

@ -320,19 +320,12 @@ void sub_running_bw(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq)
__sub_running_bw(dl_se->dl_bw, dl_rq);
}
static void dl_change_utilization(struct task_struct *p, u64 new_bw)
static void dl_rq_change_utilization(struct rq *rq, struct sched_dl_entity *dl_se, u64 new_bw)
{
struct rq *rq;
if (dl_se->dl_non_contending) {
sub_running_bw(dl_se, &rq->dl);
dl_se->dl_non_contending = 0;
WARN_ON_ONCE(p->dl.flags & SCHED_FLAG_SUGOV);
if (task_on_rq_queued(p))
return;
rq = task_rq(p);
if (p->dl.dl_non_contending) {
sub_running_bw(&p->dl, &rq->dl);
p->dl.dl_non_contending = 0;
/*
* If the timer handler is currently running and the
* timer cannot be canceled, inactive_task_timer()
@ -340,13 +333,25 @@ static void dl_change_utilization(struct task_struct *p, u64 new_bw)
* will not touch the rq's active utilization,
* so we are still safe.
*/
if (hrtimer_try_to_cancel(&p->dl.inactive_timer) == 1)
put_task_struct(p);
if (hrtimer_try_to_cancel(&dl_se->inactive_timer) == 1) {
if (!dl_server(dl_se))
put_task_struct(dl_task_of(dl_se));
}
}
__sub_rq_bw(p->dl.dl_bw, &rq->dl);
__sub_rq_bw(dl_se->dl_bw, &rq->dl);
__add_rq_bw(new_bw, &rq->dl);
}
static void dl_change_utilization(struct task_struct *p, u64 new_bw)
{
WARN_ON_ONCE(p->dl.flags & SCHED_FLAG_SUGOV);
if (task_on_rq_queued(p))
return;
dl_rq_change_utilization(task_rq(p), &p->dl, new_bw);
}
static void __dl_clear_params(struct sched_dl_entity *dl_se);
/*
@ -771,6 +776,15 @@ static inline void replenish_dl_new_period(struct sched_dl_entity *dl_se,
/* for non-boosted task, pi_of(dl_se) == dl_se */
dl_se->deadline = rq_clock(rq) + pi_of(dl_se)->dl_deadline;
dl_se->runtime = pi_of(dl_se)->dl_runtime;
/*
* If it is a deferred reservation, and the server
* is not handling an starvation case, defer it.
*/
if (dl_se->dl_defer & !dl_se->dl_defer_running) {
dl_se->dl_throttled = 1;
dl_se->dl_defer_armed = 1;
}
}
/*
@ -809,6 +823,9 @@ static inline void setup_new_dl_entity(struct sched_dl_entity *dl_se)
replenish_dl_new_period(dl_se, rq);
}
static int start_dl_timer(struct sched_dl_entity *dl_se);
static bool dl_entity_overflow(struct sched_dl_entity *dl_se, u64 t);
/*
* Pure Earliest Deadline First (EDF) scheduling does not deal with the
* possibility of a entity lasting more than what it declared, and thus
@ -837,9 +854,18 @@ static void replenish_dl_entity(struct sched_dl_entity *dl_se)
/*
* This could be the case for a !-dl task that is boosted.
* Just go with full inherited parameters.
*
* Or, it could be the case of a deferred reservation that
* was not able to consume its runtime in background and
* reached this point with current u > U.
*
* In both cases, set a new period.
*/
if (dl_se->dl_deadline == 0)
replenish_dl_new_period(dl_se, rq);
if (dl_se->dl_deadline == 0 ||
(dl_se->dl_defer_armed && dl_entity_overflow(dl_se, rq_clock(rq)))) {
dl_se->deadline = rq_clock(rq) + pi_of(dl_se)->dl_deadline;
dl_se->runtime = pi_of(dl_se)->dl_runtime;
}
if (dl_se->dl_yielded && dl_se->runtime > 0)
dl_se->runtime = 0;
@ -873,6 +899,44 @@ static void replenish_dl_entity(struct sched_dl_entity *dl_se)
dl_se->dl_yielded = 0;
if (dl_se->dl_throttled)
dl_se->dl_throttled = 0;
/*
* If this is the replenishment of a deferred reservation,
* clear the flag and return.
*/
if (dl_se->dl_defer_armed) {
dl_se->dl_defer_armed = 0;
return;
}
/*
* A this point, if the deferred server is not armed, and the deadline
* is in the future, if it is not running already, throttle the server
* and arm the defer timer.
*/
if (dl_se->dl_defer && !dl_se->dl_defer_running &&
dl_time_before(rq_clock(dl_se->rq), dl_se->deadline - dl_se->runtime)) {
if (!is_dl_boosted(dl_se) && dl_se->server_has_tasks(dl_se)) {
/*
* Set dl_se->dl_defer_armed and dl_throttled variables to
* inform the start_dl_timer() that this is a deferred
* activation.
*/
dl_se->dl_defer_armed = 1;
dl_se->dl_throttled = 1;
if (!start_dl_timer(dl_se)) {
/*
* If for whatever reason (delays), a previous timer was
* queued but not serviced, cancel it and clean the
* deferrable server variables intended for start_dl_timer().
*/
hrtimer_try_to_cancel(&dl_se->dl_timer);
dl_se->dl_defer_armed = 0;
dl_se->dl_throttled = 0;
}
}
}
}
/*
@ -1023,6 +1087,15 @@ static void update_dl_entity(struct sched_dl_entity *dl_se)
}
replenish_dl_new_period(dl_se, rq);
} else if (dl_server(dl_se) && dl_se->dl_defer) {
/*
* The server can still use its previous deadline, so check if
* it left the dl_defer_running state.
*/
if (!dl_se->dl_defer_running) {
dl_se->dl_defer_armed = 1;
dl_se->dl_throttled = 1;
}
}
}
@ -1055,8 +1128,21 @@ static int start_dl_timer(struct sched_dl_entity *dl_se)
* We want the timer to fire at the deadline, but considering
* that it is actually coming from rq->clock and not from
* hrtimer's time base reading.
*
* The deferred reservation will have its timer set to
* (deadline - runtime). At that point, the CBS rule will decide
* if the current deadline can be used, or if a replenishment is
* required to avoid add too much pressure on the system
* (current u > U).
*/
act = ns_to_ktime(dl_next_period(dl_se));
if (dl_se->dl_defer_armed) {
WARN_ON_ONCE(!dl_se->dl_throttled);
act = ns_to_ktime(dl_se->deadline - dl_se->runtime);
} else {
/* act = deadline - rel-deadline + period */
act = ns_to_ktime(dl_next_period(dl_se));
}
now = hrtimer_cb_get_time(timer);
delta = ktime_to_ns(now) - rq_clock(rq);
act = ktime_add_ns(act, delta);
@ -1106,6 +1192,62 @@ static void __push_dl_task(struct rq *rq, struct rq_flags *rf)
#endif
}
/* a defer timer will not be reset if the runtime consumed was < dl_server_min_res */
static const u64 dl_server_min_res = 1 * NSEC_PER_MSEC;
static enum hrtimer_restart dl_server_timer(struct hrtimer *timer, struct sched_dl_entity *dl_se)
{
struct rq *rq = rq_of_dl_se(dl_se);
u64 fw;
scoped_guard (rq_lock, rq) {
struct rq_flags *rf = &scope.rf;
if (!dl_se->dl_throttled || !dl_se->dl_runtime)
return HRTIMER_NORESTART;
sched_clock_tick();
update_rq_clock(rq);
if (!dl_se->dl_runtime)
return HRTIMER_NORESTART;
if (!dl_se->server_has_tasks(dl_se)) {
replenish_dl_entity(dl_se);
return HRTIMER_NORESTART;
}
if (dl_se->dl_defer_armed) {
/*
* First check if the server could consume runtime in background.
* If so, it is possible to push the defer timer for this amount
* of time. The dl_server_min_res serves as a limit to avoid
* forwarding the timer for a too small amount of time.
*/
if (dl_time_before(rq_clock(dl_se->rq),
(dl_se->deadline - dl_se->runtime - dl_server_min_res))) {
/* reset the defer timer */
fw = dl_se->deadline - rq_clock(dl_se->rq) - dl_se->runtime;
hrtimer_forward_now(timer, ns_to_ktime(fw));
return HRTIMER_RESTART;
}
dl_se->dl_defer_running = 1;
}
enqueue_dl_entity(dl_se, ENQUEUE_REPLENISH);
if (!dl_task(dl_se->rq->curr) || dl_entity_preempt(dl_se, &dl_se->rq->curr->dl))
resched_curr(rq);
__push_dl_task(rq, rf);
}
return HRTIMER_NORESTART;
}
/*
* This is the bandwidth enforcement timer callback. If here, we know
* a task is not on its dl_rq, since the fact that the timer was running
@ -1128,28 +1270,8 @@ static enum hrtimer_restart dl_task_timer(struct hrtimer *timer)
struct rq_flags rf;
struct rq *rq;
if (dl_server(dl_se)) {
struct rq *rq = rq_of_dl_se(dl_se);
struct rq_flags rf;
rq_lock(rq, &rf);
if (dl_se->dl_throttled) {
sched_clock_tick();
update_rq_clock(rq);
if (dl_se->server_has_tasks(dl_se)) {
enqueue_dl_entity(dl_se, ENQUEUE_REPLENISH);
resched_curr(rq);
__push_dl_task(rq, &rf);
} else {
replenish_dl_entity(dl_se);
}
}
rq_unlock(rq, &rf);
return HRTIMER_NORESTART;
}
if (dl_server(dl_se))
return dl_server_timer(timer, dl_se);
p = dl_task_of(dl_se);
rq = task_rq_lock(p, &rf);
@ -1319,22 +1441,10 @@ static u64 grub_reclaim(u64 delta, struct rq *rq, struct sched_dl_entity *dl_se)
return (delta * u_act) >> BW_SHIFT;
}
static inline void
update_stats_dequeue_dl(struct dl_rq *dl_rq, struct sched_dl_entity *dl_se,
int flags);
static void update_curr_dl_se(struct rq *rq, struct sched_dl_entity *dl_se, s64 delta_exec)
s64 dl_scaled_delta_exec(struct rq *rq, struct sched_dl_entity *dl_se, s64 delta_exec)
{
s64 scaled_delta_exec;
if (unlikely(delta_exec <= 0)) {
if (unlikely(dl_se->dl_yielded))
goto throttle;
return;
}
if (dl_entity_is_special(dl_se))
return;
/*
* For tasks that participate in GRUB, we implement GRUB-PA: the
* spare reclaimed bandwidth is used to clock down frequency.
@ -1353,8 +1463,64 @@ static void update_curr_dl_se(struct rq *rq, struct sched_dl_entity *dl_se, s64
scaled_delta_exec = cap_scale(scaled_delta_exec, scale_cpu);
}
return scaled_delta_exec;
}
static inline void
update_stats_dequeue_dl(struct dl_rq *dl_rq, struct sched_dl_entity *dl_se,
int flags);
static void update_curr_dl_se(struct rq *rq, struct sched_dl_entity *dl_se, s64 delta_exec)
{
s64 scaled_delta_exec;
if (unlikely(delta_exec <= 0)) {
if (unlikely(dl_se->dl_yielded))
goto throttle;
return;
}
if (dl_server(dl_se) && dl_se->dl_throttled && !dl_se->dl_defer)
return;
if (dl_entity_is_special(dl_se))
return;
scaled_delta_exec = dl_scaled_delta_exec(rq, dl_se, delta_exec);
dl_se->runtime -= scaled_delta_exec;
/*
* The fair server can consume its runtime while throttled (not queued/
* running as regular CFS).
*
* If the server consumes its entire runtime in this state. The server
* is not required for the current period. Thus, reset the server by
* starting a new period, pushing the activation.
*/
if (dl_se->dl_defer && dl_se->dl_throttled && dl_runtime_exceeded(dl_se)) {
/*
* If the server was previously activated - the starving condition
* took place, it this point it went away because the fair scheduler
* was able to get runtime in background. So return to the initial
* state.
*/
dl_se->dl_defer_running = 0;
hrtimer_try_to_cancel(&dl_se->dl_timer);
replenish_dl_new_period(dl_se, dl_se->rq);
/*
* Not being able to start the timer seems problematic. If it could not
* be started for whatever reason, we need to "unthrottle" the DL server
* and queue right away. Otherwise nothing might queue it. That's similar
* to what enqueue_dl_entity() does on start_dl_timer==0. For now, just warn.
*/
WARN_ON_ONCE(!start_dl_timer(dl_se));
return;
}
throttle:
if (dl_runtime_exceeded(dl_se) || dl_se->dl_yielded) {
dl_se->dl_throttled = 1;
@ -1381,6 +1547,14 @@ static void update_curr_dl_se(struct rq *rq, struct sched_dl_entity *dl_se, s64
resched_curr(rq);
}
/*
* The fair server (sole dl_server) does not account for real-time
* workload because it is running fair work.
*/
if (dl_se == &rq->fair_server)
return;
#ifdef CONFIG_RT_GROUP_SCHED
/*
* Because -- for now -- we share the rt bandwidth, we need to
* account our runtime there too, otherwise actual rt tasks
@ -1405,34 +1579,155 @@ static void update_curr_dl_se(struct rq *rq, struct sched_dl_entity *dl_se, s64
rt_rq->rt_time += delta_exec;
raw_spin_unlock(&rt_rq->rt_runtime_lock);
}
#endif
}
/*
* In the non-defer mode, the idle time is not accounted, as the
* server provides a guarantee.
*
* If the dl_server is in defer mode, the idle time is also considered
* as time available for the fair server, avoiding a penalty for the
* rt scheduler that did not consumed that time.
*/
void dl_server_update_idle_time(struct rq *rq, struct task_struct *p)
{
s64 delta_exec, scaled_delta_exec;
if (!rq->fair_server.dl_defer)
return;
/* no need to discount more */
if (rq->fair_server.runtime < 0)
return;
delta_exec = rq_clock_task(rq) - p->se.exec_start;
if (delta_exec < 0)
return;
scaled_delta_exec = dl_scaled_delta_exec(rq, &rq->fair_server, delta_exec);
rq->fair_server.runtime -= scaled_delta_exec;
if (rq->fair_server.runtime < 0) {
rq->fair_server.dl_defer_running = 0;
rq->fair_server.runtime = 0;
}
p->se.exec_start = rq_clock_task(rq);
}
void dl_server_update(struct sched_dl_entity *dl_se, s64 delta_exec)
{
update_curr_dl_se(dl_se->rq, dl_se, delta_exec);
/* 0 runtime = fair server disabled */
if (dl_se->dl_runtime)
update_curr_dl_se(dl_se->rq, dl_se, delta_exec);
}
void dl_server_start(struct sched_dl_entity *dl_se)
{
struct rq *rq = dl_se->rq;
/*
* XXX: the apply do not work fine at the init phase for the
* fair server because things are not yet set. We need to improve
* this before getting generic.
*/
if (!dl_server(dl_se)) {
u64 runtime = 50 * NSEC_PER_MSEC;
u64 period = 1000 * NSEC_PER_MSEC;
dl_server_apply_params(dl_se, runtime, period, 1);
dl_se->dl_server = 1;
dl_se->dl_defer = 1;
setup_new_dl_entity(dl_se);
}
if (!dl_se->dl_runtime)
return;
enqueue_dl_entity(dl_se, ENQUEUE_WAKEUP);
if (!dl_task(dl_se->rq->curr) || dl_entity_preempt(dl_se, &rq->curr->dl))
resched_curr(dl_se->rq);
}
void dl_server_stop(struct sched_dl_entity *dl_se)
{
if (!dl_se->dl_runtime)
return;
dequeue_dl_entity(dl_se, DEQUEUE_SLEEP);
hrtimer_try_to_cancel(&dl_se->dl_timer);
dl_se->dl_defer_armed = 0;
dl_se->dl_throttled = 0;
}
void dl_server_init(struct sched_dl_entity *dl_se, struct rq *rq,
dl_server_has_tasks_f has_tasks,
dl_server_pick_f pick)
dl_server_pick_f pick_task)
{
dl_se->rq = rq;
dl_se->server_has_tasks = has_tasks;
dl_se->server_pick = pick;
dl_se->server_pick_task = pick_task;
}
void __dl_server_attach_root(struct sched_dl_entity *dl_se, struct rq *rq)
{
u64 new_bw = dl_se->dl_bw;
int cpu = cpu_of(rq);
struct dl_bw *dl_b;
dl_b = dl_bw_of(cpu_of(rq));
guard(raw_spinlock)(&dl_b->lock);
if (!dl_bw_cpus(cpu))
return;
__dl_add(dl_b, new_bw, dl_bw_cpus(cpu));
}
int dl_server_apply_params(struct sched_dl_entity *dl_se, u64 runtime, u64 period, bool init)
{
u64 old_bw = init ? 0 : to_ratio(dl_se->dl_period, dl_se->dl_runtime);
u64 new_bw = to_ratio(period, runtime);
struct rq *rq = dl_se->rq;
int cpu = cpu_of(rq);
struct dl_bw *dl_b;
unsigned long cap;
int retval = 0;
int cpus;
dl_b = dl_bw_of(cpu);
guard(raw_spinlock)(&dl_b->lock);
cpus = dl_bw_cpus(cpu);
cap = dl_bw_capacity(cpu);
if (__dl_overflow(dl_b, cap, old_bw, new_bw))
return -EBUSY;
if (init) {
__add_rq_bw(new_bw, &rq->dl);
__dl_add(dl_b, new_bw, cpus);
} else {
__dl_sub(dl_b, dl_se->dl_bw, cpus);
__dl_add(dl_b, new_bw, cpus);
dl_rq_change_utilization(rq, dl_se, new_bw);
}
dl_se->dl_runtime = runtime;
dl_se->dl_deadline = period;
dl_se->dl_period = period;
dl_se->runtime = 0;
dl_se->deadline = 0;
dl_se->dl_bw = to_ratio(dl_se->dl_period, dl_se->dl_runtime);
dl_se->dl_density = to_ratio(dl_se->dl_deadline, dl_se->dl_runtime);
return retval;
}
/*
@ -1599,46 +1894,40 @@ static inline bool __dl_less(struct rb_node *a, const struct rb_node *b)
return dl_time_before(__node_2_dle(a)->deadline, __node_2_dle(b)->deadline);
}
static inline struct sched_statistics *
static __always_inline struct sched_statistics *
__schedstats_from_dl_se(struct sched_dl_entity *dl_se)
{
if (!schedstat_enabled())
return NULL;
if (dl_server(dl_se))
return NULL;
return &dl_task_of(dl_se)->stats;
}
static inline void
update_stats_wait_start_dl(struct dl_rq *dl_rq, struct sched_dl_entity *dl_se)
{
struct sched_statistics *stats;
if (!schedstat_enabled())
return;
stats = __schedstats_from_dl_se(dl_se);
__update_stats_wait_start(rq_of_dl_rq(dl_rq), dl_task_of(dl_se), stats);
struct sched_statistics *stats = __schedstats_from_dl_se(dl_se);
if (stats)
__update_stats_wait_start(rq_of_dl_rq(dl_rq), dl_task_of(dl_se), stats);
}
static inline void
update_stats_wait_end_dl(struct dl_rq *dl_rq, struct sched_dl_entity *dl_se)
{
struct sched_statistics *stats;
if (!schedstat_enabled())
return;
stats = __schedstats_from_dl_se(dl_se);
__update_stats_wait_end(rq_of_dl_rq(dl_rq), dl_task_of(dl_se), stats);
struct sched_statistics *stats = __schedstats_from_dl_se(dl_se);
if (stats)
__update_stats_wait_end(rq_of_dl_rq(dl_rq), dl_task_of(dl_se), stats);
}
static inline void
update_stats_enqueue_sleeper_dl(struct dl_rq *dl_rq, struct sched_dl_entity *dl_se)
{
struct sched_statistics *stats;
if (!schedstat_enabled())
return;
stats = __schedstats_from_dl_se(dl_se);
__update_stats_enqueue_sleeper(rq_of_dl_rq(dl_rq), dl_task_of(dl_se), stats);
struct sched_statistics *stats = __schedstats_from_dl_se(dl_se);
if (stats)
__update_stats_enqueue_sleeper(rq_of_dl_rq(dl_rq), dl_task_of(dl_se), stats);
}
static inline void
@ -1735,7 +2024,7 @@ enqueue_dl_entity(struct sched_dl_entity *dl_se, int flags)
* be counted in the active utilization; hence, we need to call
* add_running_bw().
*/
if (dl_se->dl_throttled && !(flags & ENQUEUE_REPLENISH)) {
if (!dl_se->dl_defer && dl_se->dl_throttled && !(flags & ENQUEUE_REPLENISH)) {
if (flags & ENQUEUE_WAKEUP)
task_contending(dl_se, flags);
@ -1757,6 +2046,25 @@ enqueue_dl_entity(struct sched_dl_entity *dl_se, int flags)
setup_new_dl_entity(dl_se);
}
/*
* If the reservation is still throttled, e.g., it got replenished but is a
* deferred task and still got to wait, don't enqueue.
*/
if (dl_se->dl_throttled && start_dl_timer(dl_se))
return;
/*
* We're about to enqueue, make sure we're not ->dl_throttled!
* In case the timer was not started, say because the defer time
* has passed, mark as not throttled and mark unarmed.
* Also cancel earlier timers, since letting those run is pointless.
*/
if (dl_se->dl_throttled) {
hrtimer_try_to_cancel(&dl_se->dl_timer);
dl_se->dl_defer_armed = 0;
dl_se->dl_throttled = 0;
}
__enqueue_dl_entity(dl_se);
}
@ -1846,7 +2154,7 @@ static void enqueue_task_dl(struct rq *rq, struct task_struct *p, int flags)
enqueue_pushable_dl_task(rq, p);
}
static void dequeue_task_dl(struct rq *rq, struct task_struct *p, int flags)
static bool dequeue_task_dl(struct rq *rq, struct task_struct *p, int flags)
{
update_curr_dl(rq);
@ -1856,6 +2164,8 @@ static void dequeue_task_dl(struct rq *rq, struct task_struct *p, int flags)
dequeue_dl_entity(&p->dl, flags);
if (!p->dl.dl_throttled && !dl_server(&p->dl))
dequeue_pushable_dl_task(rq, p);
return true;
}
/*
@ -2074,6 +2384,9 @@ static void set_next_task_dl(struct rq *rq, struct task_struct *p, bool first)
update_dl_rq_load_avg(rq_clock_pelt(rq), rq, 0);
deadline_queue_push_tasks(rq);
if (hrtick_enabled(rq))
start_hrtick_dl(rq, &p->dl);
}
static struct sched_dl_entity *pick_next_dl_entity(struct dl_rq *dl_rq)
@ -2086,7 +2399,11 @@ static struct sched_dl_entity *pick_next_dl_entity(struct dl_rq *dl_rq)
return __node_2_dle(left);
}
static struct task_struct *pick_task_dl(struct rq *rq)
/*
* __pick_next_task_dl - Helper to pick the next -deadline task to run.
* @rq: The runqueue to pick the next task from.
*/
static struct task_struct *__pick_task_dl(struct rq *rq)
{
struct sched_dl_entity *dl_se;
struct dl_rq *dl_rq = &rq->dl;
@ -2100,14 +2417,13 @@ static struct task_struct *pick_task_dl(struct rq *rq)
WARN_ON_ONCE(!dl_se);
if (dl_server(dl_se)) {
p = dl_se->server_pick(dl_se);
p = dl_se->server_pick_task(dl_se);
if (!p) {
WARN_ON_ONCE(1);
dl_se->dl_yielded = 1;
update_curr_dl_se(rq, dl_se, 0);
goto again;
}
p->dl_server = dl_se;
rq->dl_server = dl_se;
} else {
p = dl_task_of(dl_se);
}
@ -2115,24 +2431,12 @@ static struct task_struct *pick_task_dl(struct rq *rq)
return p;
}
static struct task_struct *pick_next_task_dl(struct rq *rq)
static struct task_struct *pick_task_dl(struct rq *rq)
{
struct task_struct *p;
p = pick_task_dl(rq);
if (!p)
return p;
if (!p->dl_server)
set_next_task_dl(rq, p, true);
if (hrtick_enabled(rq))
start_hrtick_dl(rq, &p->dl);
return p;
return __pick_task_dl(rq);
}
static void put_prev_task_dl(struct rq *rq, struct task_struct *p)
static void put_prev_task_dl(struct rq *rq, struct task_struct *p, struct task_struct *next)
{
struct sched_dl_entity *dl_se = &p->dl;
struct dl_rq *dl_rq = &rq->dl;
@ -2824,13 +3128,12 @@ DEFINE_SCHED_CLASS(dl) = {
.wakeup_preempt = wakeup_preempt_dl,
.pick_next_task = pick_next_task_dl,
.pick_task = pick_task_dl,
.put_prev_task = put_prev_task_dl,
.set_next_task = set_next_task_dl,
#ifdef CONFIG_SMP
.balance = balance_dl,
.pick_task = pick_task_dl,
.select_task_rq = select_task_rq_dl,
.migrate_task_rq = migrate_task_rq_dl,
.set_cpus_allowed = set_cpus_allowed_dl,

198
kernel/sched/debug.c
View File

@ -333,8 +333,165 @@ static const struct file_operations sched_debug_fops = {
.release = seq_release,
};
enum dl_param {
DL_RUNTIME = 0,
DL_PERIOD,
};
static unsigned long fair_server_period_max = (1UL << 22) * NSEC_PER_USEC; /* ~4 seconds */
static unsigned long fair_server_period_min = (100) * NSEC_PER_USEC; /* 100 us */
static ssize_t sched_fair_server_write(struct file *filp, const char __user *ubuf,
size_t cnt, loff_t *ppos, enum dl_param param)
{
long cpu = (long) ((struct seq_file *) filp->private_data)->private;
struct rq *rq = cpu_rq(cpu);
u64 runtime, period;
size_t err;
int retval;
u64 value;
err = kstrtoull_from_user(ubuf, cnt, 10, &value);
if (err)
return err;
scoped_guard (rq_lock_irqsave, rq) {
runtime = rq->fair_server.dl_runtime;
period = rq->fair_server.dl_period;
switch (param) {
case DL_RUNTIME:
if (runtime == value)
break;
runtime = value;
break;
case DL_PERIOD:
if (value == period)
break;
period = value;
break;
}
if (runtime > period ||
period > fair_server_period_max ||
period < fair_server_period_min) {
return -EINVAL;
}
if (rq->cfs.h_nr_running) {
update_rq_clock(rq);
dl_server_stop(&rq->fair_server);
}
retval = dl_server_apply_params(&rq->fair_server, runtime, period, 0);
if (retval)
cnt = retval;
if (!runtime)
printk_deferred("Fair server disabled in CPU %d, system may crash due to starvation.\n",
cpu_of(rq));
if (rq->cfs.h_nr_running)
dl_server_start(&rq->fair_server);
}
*ppos += cnt;
return cnt;
}
static size_t sched_fair_server_show(struct seq_file *m, void *v, enum dl_param param)
{
unsigned long cpu = (unsigned long) m->private;
struct rq *rq = cpu_rq(cpu);
u64 value;
switch (param) {
case DL_RUNTIME:
value = rq->fair_server.dl_runtime;
break;
case DL_PERIOD:
value = rq->fair_server.dl_period;
break;
}
seq_printf(m, "%llu\n", value);
return 0;
}
static ssize_t
sched_fair_server_runtime_write(struct file *filp, const char __user *ubuf,
size_t cnt, loff_t *ppos)
{
return sched_fair_server_write(filp, ubuf, cnt, ppos, DL_RUNTIME);
}
static int sched_fair_server_runtime_show(struct seq_file *m, void *v)
{
return sched_fair_server_show(m, v, DL_RUNTIME);
}
static int sched_fair_server_runtime_open(struct inode *inode, struct file *filp)
{
return single_open(filp, sched_fair_server_runtime_show, inode->i_private);
}
static const struct file_operations fair_server_runtime_fops = {
.open = sched_fair_server_runtime_open,
.write = sched_fair_server_runtime_write,
.read = seq_read,
.llseek = seq_lseek,
.release = single_release,
};
static ssize_t
sched_fair_server_period_write(struct file *filp, const char __user *ubuf,
size_t cnt, loff_t *ppos)
{
return sched_fair_server_write(filp, ubuf, cnt, ppos, DL_PERIOD);
}
static int sched_fair_server_period_show(struct seq_file *m, void *v)
{
return sched_fair_server_show(m, v, DL_PERIOD);
}
static int sched_fair_server_period_open(struct inode *inode, struct file *filp)
{
return single_open(filp, sched_fair_server_period_show, inode->i_private);
}
static const struct file_operations fair_server_period_fops = {
.open = sched_fair_server_period_open,
.write = sched_fair_server_period_write,
.read = seq_read,
.llseek = seq_lseek,
.release = single_release,
};
static struct dentry *debugfs_sched;
static void debugfs_fair_server_init(void)
{
struct dentry *d_fair;
unsigned long cpu;
d_fair = debugfs_create_dir("fair_server", debugfs_sched);
if (!d_fair)
return;
for_each_possible_cpu(cpu) {
struct dentry *d_cpu;
char buf[32];
snprintf(buf, sizeof(buf), "cpu%lu", cpu);
d_cpu = debugfs_create_dir(buf, d_fair);
debugfs_create_file("runtime", 0644, d_cpu, (void *) cpu, &fair_server_runtime_fops);
debugfs_create_file("period", 0644, d_cpu, (void *) cpu, &fair_server_period_fops);
}
}
static __init int sched_init_debug(void)
{
struct dentry __maybe_unused *numa;
@ -374,6 +531,8 @@ static __init int sched_init_debug(void)
debugfs_create_file("debug", 0444, debugfs_sched, NULL, &sched_debug_fops);
debugfs_fair_server_init();
return 0;
}
late_initcall(sched_init_debug);
@ -580,27 +739,27 @@ print_task(struct seq_file *m, struct rq *rq, struct task_struct *p)
else
SEQ_printf(m, " %c", task_state_to_char(p));
SEQ_printf(m, "%15s %5d %9Ld.%06ld %c %9Ld.%06ld %9Ld.%06ld %9Ld.%06ld %9Ld %5d ",
SEQ_printf(m, " %15s %5d %9Ld.%06ld %c %9Ld.%06ld %c %9Ld.%06ld %9Ld.%06ld %9Ld %5d ",
p->comm, task_pid_nr(p),
SPLIT_NS(p->se.vruntime),
entity_eligible(cfs_rq_of(&p->se), &p->se) ? 'E' : 'N',
SPLIT_NS(p->se.deadline),
p->se.custom_slice ? 'S' : ' ',
SPLIT_NS(p->se.slice),
SPLIT_NS(p->se.sum_exec_runtime),
(long long)(p->nvcsw + p->nivcsw),
p->prio);
SEQ_printf(m, "%9lld.%06ld %9lld.%06ld %9lld.%06ld %9lld.%06ld",
SEQ_printf(m, "%9lld.%06ld %9lld.%06ld %9lld.%06ld",
SPLIT_NS(schedstat_val_or_zero(p->stats.wait_sum)),
SPLIT_NS(p->se.sum_exec_runtime),
SPLIT_NS(schedstat_val_or_zero(p->stats.sum_sleep_runtime)),
SPLIT_NS(schedstat_val_or_zero(p->stats.sum_block_runtime)));
#ifdef CONFIG_NUMA_BALANCING
SEQ_printf(m, " %d %d", task_node(p), task_numa_group_id(p));
SEQ_printf(m, " %d %d", task_node(p), task_numa_group_id(p));
#endif
#ifdef CONFIG_CGROUP_SCHED
SEQ_printf_task_group_path(m, task_group(p), " %s")
SEQ_printf_task_group_path(m, task_group(p), " %s")
#endif
SEQ_printf(m, "\n");
@ -612,10 +771,26 @@ static void print_rq(struct seq_file *m, struct rq *rq, int rq_cpu)
SEQ_printf(m, "\n");
SEQ_printf(m, "runnable tasks:\n");
SEQ_printf(m, " S task PID tree-key switches prio"
" wait-time sum-exec sum-sleep\n");
SEQ_printf(m, " S task PID vruntime eligible "
"deadline slice sum-exec switches "
"prio wait-time sum-sleep sum-block"
#ifdef CONFIG_NUMA_BALANCING
" node group-id"
#endif
#ifdef CONFIG_CGROUP_SCHED
" group-path"
#endif
"\n");
SEQ_printf(m, "-------------------------------------------------------"
"------------------------------------------------------\n");
"------------------------------------------------------"
"------------------------------------------------------"
#ifdef CONFIG_NUMA_BALANCING
"--------------"
#endif
#ifdef CONFIG_CGROUP_SCHED
"--------------"
#endif
"\n");
rcu_read_lock();
for_each_process_thread(g, p) {
@ -641,8 +816,6 @@ void print_cfs_rq(struct seq_file *m, int cpu, struct cfs_rq *cfs_rq)
SEQ_printf(m, "\n");
SEQ_printf(m, "cfs_rq[%d]:\n", cpu);
#endif
SEQ_printf(m, " .%-30s: %Ld.%06ld\n", "exec_clock",
SPLIT_NS(cfs_rq->exec_clock));
raw_spin_rq_lock_irqsave(rq, flags);
root = __pick_root_entity(cfs_rq);
@ -669,8 +842,6 @@ void print_cfs_rq(struct seq_file *m, int cpu, struct cfs_rq *cfs_rq)
SPLIT_NS(right_vruntime));
spread = right_vruntime - left_vruntime;
SEQ_printf(m, " .%-30s: %Ld.%06ld\n", "spread", SPLIT_NS(spread));
SEQ_printf(m, " .%-30s: %d\n", "nr_spread_over",
cfs_rq->nr_spread_over);
SEQ_printf(m, " .%-30s: %d\n", "nr_running", cfs_rq->nr_running);
SEQ_printf(m, " .%-30s: %d\n", "h_nr_running", cfs_rq->h_nr_running);
SEQ_printf(m, " .%-30s: %d\n", "idle_nr_running",
@ -730,9 +901,12 @@ void print_rt_rq(struct seq_file *m, int cpu, struct rt_rq *rt_rq)
SEQ_printf(m, " .%-30s: %Ld.%06ld\n", #x, SPLIT_NS(rt_rq->x))
PU(rt_nr_running);
#ifdef CONFIG_RT_GROUP_SCHED
P(rt_throttled);
PN(rt_time);
PN(rt_runtime);
#endif
#undef PN
#undef PU

770
kernel/sched/fair.c
View File

File diff suppressed because it is too large Load Diff

30
kernel/sched/features.h
View File

@ -5,8 +5,24 @@
* sleep+wake cycles. EEVDF placement strategy #1, #2 if disabled.
*/
SCHED_FEAT(PLACE_LAG, true)
/*
* Give new tasks half a slice to ease into the competition.
*/
SCHED_FEAT(PLACE_DEADLINE_INITIAL, true)
/*
* Preserve relative virtual deadline on 'migration'.
*/
SCHED_FEAT(PLACE_REL_DEADLINE, true)
/*
* Inhibit (wakeup) preemption until the current task has either matched the
* 0-lag point or until is has exhausted it's slice.
*/
SCHED_FEAT(RUN_TO_PARITY, true)
/*
* Allow wakeup of tasks with a shorter slice to cancel RESPECT_SLICE for
* current.
*/
SCHED_FEAT(PREEMPT_SHORT, true)
/*
* Prefer to schedule the task we woke last (assuming it failed
@ -21,6 +37,18 @@ SCHED_FEAT(NEXT_BUDDY, false)
*/
SCHED_FEAT(CACHE_HOT_BUDDY, true)
/*
* Delay dequeueing tasks until they get selected or woken.
*
* By delaying the dequeue for non-eligible tasks, they remain in the
* competition and can burn off their negative lag. When they get selected
* they'll have positive lag by definition.
*
* DELAY_ZERO clips the lag on dequeue (or wakeup) to 0.
*/
SCHED_FEAT(DELAY_DEQUEUE, true)
SCHED_FEAT(DELAY_ZERO, true)
/*
* Allow wakeup-time preemption of the current task:
*/
@ -85,5 +113,3 @@ SCHED_FEAT(WA_BIAS, true)
SCHED_FEAT(UTIL_EST, true)
SCHED_FEAT(LATENCY_WARN, false)
SCHED_FEAT(HZ_BW, true)

23
kernel/sched/idle.c
View File

@ -450,43 +450,35 @@ static void wakeup_preempt_idle(struct rq *rq, struct task_struct *p, int flags)
resched_curr(rq);
}
static void put_prev_task_idle(struct rq *rq, struct task_struct *prev)
static void put_prev_task_idle(struct rq *rq, struct task_struct *prev, struct task_struct *next)
{
dl_server_update_idle_time(rq, prev);
}
static void set_next_task_idle(struct rq *rq, struct task_struct *next, bool first)
{
update_idle_core(rq);
schedstat_inc(rq->sched_goidle);
next->se.exec_start = rq_clock_task(rq);
}
#ifdef CONFIG_SMP
static struct task_struct *pick_task_idle(struct rq *rq)
struct task_struct *pick_task_idle(struct rq *rq)
{
return rq->idle;
}
#endif
struct task_struct *pick_next_task_idle(struct rq *rq)
{
struct task_struct *next = rq->idle;
set_next_task_idle(rq, next, true);
return next;
}
/*
* It is not legal to sleep in the idle task - print a warning
* message if some code attempts to do it:
*/
static void
static bool
dequeue_task_idle(struct rq *rq, struct task_struct *p, int flags)
{
raw_spin_rq_unlock_irq(rq);
printk(KERN_ERR "bad: scheduling from the idle thread!\n");
dump_stack();
raw_spin_rq_lock_irq(rq);
return true;
}
/*
@ -528,13 +520,12 @@ DEFINE_SCHED_CLASS(idle) = {
.wakeup_preempt = wakeup_preempt_idle,
.pick_next_task = pick_next_task_idle,
.pick_task = pick_task_idle,
.put_prev_task = put_prev_task_idle,
.set_next_task = set_next_task_idle,
#ifdef CONFIG_SMP
.balance = balance_idle,
.pick_task = pick_task_idle,
.select_task_rq = select_task_rq_idle,
.set_cpus_allowed = set_cpus_allowed_common,
#endif

261
kernel/sched/rt.c
View File

@ -8,10 +8,6 @@ int sched_rr_timeslice = RR_TIMESLICE;
/* More than 4 hours if BW_SHIFT equals 20. */
static const u64 max_rt_runtime = MAX_BW;
static int do_sched_rt_period_timer(struct rt_bandwidth *rt_b, int overrun);
struct rt_bandwidth def_rt_bandwidth;
/*
* period over which we measure -rt task CPU usage in us.
* default: 1s
@ -66,6 +62,40 @@ static int __init sched_rt_sysctl_init(void)
late_initcall(sched_rt_sysctl_init);
#endif
void init_rt_rq(struct rt_rq *rt_rq)
{
struct rt_prio_array *array;
int i;
array = &rt_rq->active;
for (i = 0; i < MAX_RT_PRIO; i++) {
INIT_LIST_HEAD(array->queue + i);
__clear_bit(i, array->bitmap);
}
/* delimiter for bitsearch: */
__set_bit(MAX_RT_PRIO, array->bitmap);
#if defined CONFIG_SMP
rt_rq->highest_prio.curr = MAX_RT_PRIO-1;
rt_rq->highest_prio.next = MAX_RT_PRIO-1;
rt_rq->overloaded = 0;
plist_head_init(&rt_rq->pushable_tasks);
#endif /* CONFIG_SMP */
/* We start is dequeued state, because no RT tasks are queued */
rt_rq->rt_queued = 0;
#ifdef CONFIG_RT_GROUP_SCHED
rt_rq->rt_time = 0;
rt_rq->rt_throttled = 0;
rt_rq->rt_runtime = 0;
raw_spin_lock_init(&rt_rq->rt_runtime_lock);
#endif
}
#ifdef CONFIG_RT_GROUP_SCHED
static int do_sched_rt_period_timer(struct rt_bandwidth *rt_b, int overrun);
static enum hrtimer_restart sched_rt_period_timer(struct hrtimer *timer)
{
struct rt_bandwidth *rt_b =
@ -130,35 +160,6 @@ static void start_rt_bandwidth(struct rt_bandwidth *rt_b)
do_start_rt_bandwidth(rt_b);
}
void init_rt_rq(struct rt_rq *rt_rq)
{
struct rt_prio_array *array;
int i;
array = &rt_rq->active;
for (i = 0; i < MAX_RT_PRIO; i++) {
INIT_LIST_HEAD(array->queue + i);
__clear_bit(i, array->bitmap);
}
/* delimiter for bit-search: */
__set_bit(MAX_RT_PRIO, array->bitmap);
#if defined CONFIG_SMP
rt_rq->highest_prio.curr = MAX_RT_PRIO-1;
rt_rq->highest_prio.next = MAX_RT_PRIO-1;
rt_rq->overloaded = 0;
plist_head_init(&rt_rq->pushable_tasks);
#endif /* CONFIG_SMP */
/* We start is dequeued state, because no RT tasks are queued */
rt_rq->rt_queued = 0;
rt_rq->rt_time = 0;
rt_rq->rt_throttled = 0;
rt_rq->rt_runtime = 0;
raw_spin_lock_init(&rt_rq->rt_runtime_lock);
}
#ifdef CONFIG_RT_GROUP_SCHED
static void destroy_rt_bandwidth(struct rt_bandwidth *rt_b)
{
hrtimer_cancel(&rt_b->rt_period_timer);
@ -195,7 +196,6 @@ void unregister_rt_sched_group(struct task_group *tg)
{
if (tg->rt_se)
destroy_rt_bandwidth(&tg->rt_bandwidth);
}
void free_rt_sched_group(struct task_group *tg)
@ -253,8 +253,7 @@ int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent)
if (!tg->rt_se)
goto err;
init_rt_bandwidth(&tg->rt_bandwidth,
ktime_to_ns(def_rt_bandwidth.rt_period), 0);
init_rt_bandwidth(&tg->rt_bandwidth, ktime_to_ns(global_rt_period()), 0);
for_each_possible_cpu(i) {
rt_rq = kzalloc_node(sizeof(struct rt_rq),
@ -604,70 +603,6 @@ static inline struct rt_bandwidth *sched_rt_bandwidth(struct rt_rq *rt_rq)
return &rt_rq->tg->rt_bandwidth;
}
#else /* !CONFIG_RT_GROUP_SCHED */
static inline u64 sched_rt_runtime(struct rt_rq *rt_rq)
{
return rt_rq->rt_runtime;
}
static inline u64 sched_rt_period(struct rt_rq *rt_rq)
{
return ktime_to_ns(def_rt_bandwidth.rt_period);
}
typedef struct rt_rq *rt_rq_iter_t;
#define for_each_rt_rq(rt_rq, iter, rq) \
for ((void) iter, rt_rq = &rq->rt; rt_rq; rt_rq = NULL)
#define for_each_sched_rt_entity(rt_se) \
for (; rt_se; rt_se = NULL)
static inline struct rt_rq *group_rt_rq(struct sched_rt_entity *rt_se)
{
return NULL;
}
static inline void sched_rt_rq_enqueue(struct rt_rq *rt_rq)
{
struct rq *rq = rq_of_rt_rq(rt_rq);
if (!rt_rq->rt_nr_running)
return;
enqueue_top_rt_rq(rt_rq);
resched_curr(rq);
}
static inline void sched_rt_rq_dequeue(struct rt_rq *rt_rq)
{
dequeue_top_rt_rq(rt_rq, rt_rq->rt_nr_running);
}
static inline int rt_rq_throttled(struct rt_rq *rt_rq)
{
return rt_rq->rt_throttled;
}
static inline const struct cpumask *sched_rt_period_mask(void)
{
return cpu_online_mask;
}
static inline
struct rt_rq *sched_rt_period_rt_rq(struct rt_bandwidth *rt_b, int cpu)
{
return &cpu_rq(cpu)->rt;
}
static inline struct rt_bandwidth *sched_rt_bandwidth(struct rt_rq *rt_rq)
{
return &def_rt_bandwidth;
}
#endif /* CONFIG_RT_GROUP_SCHED */
bool sched_rt_bandwidth_account(struct rt_rq *rt_rq)
{
struct rt_bandwidth *rt_b = sched_rt_bandwidth(rt_rq);
@ -859,7 +794,7 @@ static int do_sched_rt_period_timer(struct rt_bandwidth *rt_b, int overrun)
const struct cpumask *span;
span = sched_rt_period_mask();
#ifdef CONFIG_RT_GROUP_SCHED
/*
* FIXME: isolated CPUs should really leave the root task group,
* whether they are isolcpus or were isolated via cpusets, lest
@ -871,7 +806,7 @@ static int do_sched_rt_period_timer(struct rt_bandwidth *rt_b, int overrun)
*/
if (rt_b == &root_task_group.rt_bandwidth)
span = cpu_online_mask;
#endif
for_each_cpu(i, span) {
int enqueue = 0;
struct rt_rq *rt_rq = sched_rt_period_rt_rq(rt_b, i);
@ -938,18 +873,6 @@ static int do_sched_rt_period_timer(struct rt_bandwidth *rt_b, int overrun)
return idle;
}
static inline int rt_se_prio(struct sched_rt_entity *rt_se)
{
#ifdef CONFIG_RT_GROUP_SCHED
struct rt_rq *rt_rq = group_rt_rq(rt_se);
if (rt_rq)
return rt_rq->highest_prio.curr;
#endif
return rt_task_of(rt_se)->prio;
}
static int sched_rt_runtime_exceeded(struct rt_rq *rt_rq)
{
u64 runtime = sched_rt_runtime(rt_rq);
@ -993,6 +916,72 @@ static int sched_rt_runtime_exceeded(struct rt_rq *rt_rq)
return 0;
}
#else /* !CONFIG_RT_GROUP_SCHED */
typedef struct rt_rq *rt_rq_iter_t;
#define for_each_rt_rq(rt_rq, iter, rq) \
for ((void) iter, rt_rq = &rq->rt; rt_rq; rt_rq = NULL)
#define for_each_sched_rt_entity(rt_se) \
for (; rt_se; rt_se = NULL)
static inline struct rt_rq *group_rt_rq(struct sched_rt_entity *rt_se)
{
return NULL;
}
static inline void sched_rt_rq_enqueue(struct rt_rq *rt_rq)
{
struct rq *rq = rq_of_rt_rq(rt_rq);
if (!rt_rq->rt_nr_running)
return;
enqueue_top_rt_rq(rt_rq);
resched_curr(rq);
}
static inline void sched_rt_rq_dequeue(struct rt_rq *rt_rq)
{
dequeue_top_rt_rq(rt_rq, rt_rq->rt_nr_running);
}
static inline int rt_rq_throttled(struct rt_rq *rt_rq)
{
return false;
}
static inline const struct cpumask *sched_rt_period_mask(void)
{
return cpu_online_mask;
}
static inline
struct rt_rq *sched_rt_period_rt_rq(struct rt_bandwidth *rt_b, int cpu)
{
return &cpu_rq(cpu)->rt;
}
#ifdef CONFIG_SMP
static void __enable_runtime(struct rq *rq) { }
static void __disable_runtime(struct rq *rq) { }
#endif
#endif /* CONFIG_RT_GROUP_SCHED */
static inline int rt_se_prio(struct sched_rt_entity *rt_se)
{
#ifdef CONFIG_RT_GROUP_SCHED
struct rt_rq *rt_rq = group_rt_rq(rt_se);
if (rt_rq)
return rt_rq->highest_prio.curr;
#endif
return rt_task_of(rt_se)->prio;
}
/*
* Update the current task's runtime statistics. Skip current tasks that
* are not in our scheduling class.
@ -1000,7 +989,6 @@ static int sched_rt_runtime_exceeded(struct rt_rq *rt_rq)
static void update_curr_rt(struct rq *rq)
{
struct task_struct *curr = rq->curr;
struct sched_rt_entity *rt_se = &curr->rt;
s64 delta_exec;
if (curr->sched_class != &rt_sched_class)
@ -1010,6 +998,9 @@ static void update_curr_rt(struct rq *rq)
if (unlikely(delta_exec <= 0))
return;
#ifdef CONFIG_RT_GROUP_SCHED
struct sched_rt_entity *rt_se = &curr->rt;
if (!rt_bandwidth_enabled())
return;
@ -1028,6 +1019,7 @@ static void update_curr_rt(struct rq *rq)
do_start_rt_bandwidth(sched_rt_bandwidth(rt_rq));
}
}
#endif
}
static void
@ -1184,7 +1176,6 @@ dec_rt_group(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
static void
inc_rt_group(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
{
start_rt_bandwidth(&def_rt_bandwidth);
}
static inline
@ -1492,7 +1483,7 @@ enqueue_task_rt(struct rq *rq, struct task_struct *p, int flags)
enqueue_pushable_task(rq, p);
}
static void dequeue_task_rt(struct rq *rq, struct task_struct *p, int flags)
static bool dequeue_task_rt(struct rq *rq, struct task_struct *p, int flags)
{
struct sched_rt_entity *rt_se = &p->rt;
@ -1500,6 +1491,8 @@ static void dequeue_task_rt(struct rq *rq, struct task_struct *p, int flags)
dequeue_rt_entity(rt_se, flags);
dequeue_pushable_task(rq, p);
return true;
}
/*
@ -1755,17 +1748,7 @@ static struct task_struct *pick_task_rt(struct rq *rq)
return p;
}
static struct task_struct *pick_next_task_rt(struct rq *rq)
{
struct task_struct *p = pick_task_rt(rq);
if (p)
set_next_task_rt(rq, p, true);
return p;
}
static void put_prev_task_rt(struct rq *rq, struct task_struct *p)
static void put_prev_task_rt(struct rq *rq, struct task_struct *p, struct task_struct *next)
{
struct sched_rt_entity *rt_se = &p->rt;
struct rt_rq *rt_rq = &rq->rt;
@ -2652,13 +2635,12 @@ DEFINE_SCHED_CLASS(rt) = {
.wakeup_preempt = wakeup_preempt_rt,
.pick_next_task = pick_next_task_rt,
.pick_task = pick_task_rt,
.put_prev_task = put_prev_task_rt,
.set_next_task = set_next_task_rt,
#ifdef CONFIG_SMP
.balance = balance_rt,
.pick_task = pick_task_rt,
.select_task_rq = select_task_rq_rt,
.set_cpus_allowed = set_cpus_allowed_common,
.rq_online = rq_online_rt,
@ -2912,19 +2894,6 @@ int sched_rt_can_attach(struct task_group *tg, struct task_struct *tsk)
#ifdef CONFIG_SYSCTL
static int sched_rt_global_constraints(void)
{
unsigned long flags;
int i;
raw_spin_lock_irqsave(&def_rt_bandwidth.rt_runtime_lock, flags);
for_each_possible_cpu(i) {
struct rt_rq *rt_rq = &cpu_rq(i)->rt;
raw_spin_lock(&rt_rq->rt_runtime_lock);
rt_rq->rt_runtime = global_rt_runtime();
raw_spin_unlock(&rt_rq->rt_runtime_lock);
}
raw_spin_unlock_irqrestore(&def_rt_bandwidth.rt_runtime_lock, flags);
return 0;
}
#endif /* CONFIG_SYSCTL */
@ -2944,12 +2913,6 @@ static int sched_rt_global_validate(void)
static void sched_rt_do_global(void)
{
unsigned long flags;
raw_spin_lock_irqsave(&def_rt_bandwidth.rt_runtime_lock, flags);
def_rt_bandwidth.rt_runtime = global_rt_runtime();
def_rt_bandwidth.rt_period = ns_to_ktime(global_rt_period());
raw_spin_unlock_irqrestore(&def_rt_bandwidth.rt_runtime_lock, flags);
}
static int sched_rt_handler(const struct ctl_table *table, int write, void *buffer,

101
kernel/sched/sched.h
View File

@ -68,6 +68,7 @@
#include <linux/wait_api.h>
#include <linux/wait_bit.h>
#include <linux/workqueue_api.h>
#include <linux/delayacct.h>
#include <trace/events/power.h>
#include <trace/events/sched.h>
@ -335,7 +336,7 @@ extern bool __checkparam_dl(const struct sched_attr *attr);
extern bool dl_param_changed(struct task_struct *p, const struct sched_attr *attr);
extern int dl_cpuset_cpumask_can_shrink(const struct cpumask *cur, const struct cpumask *trial);
extern int dl_bw_check_overflow(int cpu);
extern s64 dl_scaled_delta_exec(struct rq *rq, struct sched_dl_entity *dl_se, s64 delta_exec);
/*
* SCHED_DEADLINE supports servers (nested scheduling) with the following
* interface:
@ -361,7 +362,14 @@ extern void dl_server_start(struct sched_dl_entity *dl_se);
extern void dl_server_stop(struct sched_dl_entity *dl_se);
extern void dl_server_init(struct sched_dl_entity *dl_se, struct rq *rq,
dl_server_has_tasks_f has_tasks,
dl_server_pick_f pick);
dl_server_pick_f pick_task);
extern void dl_server_update_idle_time(struct rq *rq,
struct task_struct *p);
extern void fair_server_init(struct rq *rq);
extern void __dl_server_attach_root(struct sched_dl_entity *dl_se, struct rq *rq);
extern int dl_server_apply_params(struct sched_dl_entity *dl_se,
u64 runtime, u64 period, bool init);
#ifdef CONFIG_CGROUP_SCHED
@ -599,17 +607,12 @@ struct cfs_rq {
s64 avg_vruntime;
u64 avg_load;
u64 exec_clock;
u64 min_vruntime;
#ifdef CONFIG_SCHED_CORE
unsigned int forceidle_seq;
u64 min_vruntime_fi;
#endif
#ifndef CONFIG_64BIT
u64 min_vruntime_copy;
#endif
struct rb_root_cached tasks_timeline;
/*
@ -619,10 +622,6 @@ struct cfs_rq {
struct sched_entity *curr;
struct sched_entity *next;
#ifdef CONFIG_SCHED_DEBUG
unsigned int nr_spread_over;
#endif
#ifdef CONFIG_SMP
/*
* CFS load tracking
@ -726,13 +725,13 @@ struct rt_rq {
#endif /* CONFIG_SMP */
int rt_queued;
#ifdef CONFIG_RT_GROUP_SCHED
int rt_throttled;
u64 rt_time;
u64 rt_runtime;
/* Nests inside the rq lock: */
raw_spinlock_t rt_runtime_lock;
#ifdef CONFIG_RT_GROUP_SCHED
unsigned int rt_nr_boosted;
struct rq *rq;
@ -820,6 +819,9 @@ static inline void se_update_runnable(struct sched_entity *se)
static inline long se_runnable(struct sched_entity *se)
{
if (se->sched_delayed)
return false;
if (entity_is_task(se))
return !!se->on_rq;
else
@ -834,6 +836,9 @@ static inline void se_update_runnable(struct sched_entity *se) { }
static inline long se_runnable(struct sched_entity *se)
{
if (se->sched_delayed)
return false;
return !!se->on_rq;
}
@ -1044,6 +1049,8 @@ struct rq {
struct rt_rq rt;
struct dl_rq dl;
struct sched_dl_entity fair_server;
#ifdef CONFIG_FAIR_GROUP_SCHED
/* list of leaf cfs_rq on this CPU: */
struct list_head leaf_cfs_rq_list;
@ -1059,6 +1066,7 @@ struct rq {
unsigned int nr_uninterruptible;
struct task_struct __rcu *curr;
struct sched_dl_entity *dl_server;
struct task_struct *idle;
struct task_struct *stop;
unsigned long next_balance;
@ -1158,7 +1166,6 @@ struct rq {
/* latency stats */
struct sched_info rq_sched_info;
unsigned long long rq_cpu_time;
/* could above be rq->cfs_rq.exec_clock + rq->rt_rq.rt_runtime ? */
/* sys_sched_yield() stats */
unsigned int yld_count;
@ -1187,6 +1194,7 @@ struct rq {
/* per rq */
struct rq *core;
struct task_struct *core_pick;
struct sched_dl_entity *core_dl_server;
unsigned int core_enabled;
unsigned int core_sched_seq;
struct rb_root core_tree;
@ -2247,11 +2255,13 @@ extern const u32 sched_prio_to_wmult[40];
*
*/
#define DEQUEUE_SLEEP 0x01
#define DEQUEUE_SLEEP 0x01 /* Matches ENQUEUE_WAKEUP */
#define DEQUEUE_SAVE 0x02 /* Matches ENQUEUE_RESTORE */
#define DEQUEUE_MOVE 0x04 /* Matches ENQUEUE_MOVE */
#define DEQUEUE_NOCLOCK 0x08 /* Matches ENQUEUE_NOCLOCK */
#define DEQUEUE_SPECIAL 0x10
#define DEQUEUE_MIGRATING 0x100 /* Matches ENQUEUE_MIGRATING */
#define DEQUEUE_DELAYED 0x200 /* Matches ENQUEUE_DELAYED */
#define ENQUEUE_WAKEUP 0x01
#define ENQUEUE_RESTORE 0x02
@ -2267,6 +2277,7 @@ extern const u32 sched_prio_to_wmult[40];
#endif
#define ENQUEUE_INITIAL 0x80
#define ENQUEUE_MIGRATING 0x100
#define ENQUEUE_DELAYED 0x200
#define RETRY_TASK ((void *)-1UL)
@ -2285,23 +2296,31 @@ struct sched_class {
#endif
void (*enqueue_task) (struct rq *rq, struct task_struct *p, int flags);
void (*dequeue_task) (struct rq *rq, struct task_struct *p, int flags);
bool (*dequeue_task) (struct rq *rq, struct task_struct *p, int flags);
void (*yield_task) (struct rq *rq);
bool (*yield_to_task)(struct rq *rq, struct task_struct *p);
void (*wakeup_preempt)(struct rq *rq, struct task_struct *p, int flags);
struct task_struct *(*pick_next_task)(struct rq *rq);
struct task_struct *(*pick_task)(struct rq *rq);
/*
* Optional! When implemented pick_next_task() should be equivalent to:
*
* next = pick_task();
* if (next) {
* put_prev_task(prev);
* set_next_task_first(next);
* }
*/
struct task_struct *(*pick_next_task)(struct rq *rq, struct task_struct *prev);
void (*put_prev_task)(struct rq *rq, struct task_struct *p);
void (*put_prev_task)(struct rq *rq, struct task_struct *p, struct task_struct *next);
void (*set_next_task)(struct rq *rq, struct task_struct *p, bool first);
#ifdef CONFIG_SMP
int (*balance)(struct rq *rq, struct task_struct *prev, struct rq_flags *rf);
int (*select_task_rq)(struct task_struct *p, int task_cpu, int flags);
struct task_struct * (*pick_task)(struct rq *rq);
void (*migrate_task_rq)(struct task_struct *p, int new_cpu);
void (*task_woken)(struct rq *this_rq, struct task_struct *task);
@ -2345,7 +2364,7 @@ struct sched_class {
static inline void put_prev_task(struct rq *rq, struct task_struct *prev)
{
WARN_ON_ONCE(rq->curr != prev);
prev->sched_class->put_prev_task(rq, prev);
prev->sched_class->put_prev_task(rq, prev, NULL);
}
static inline void set_next_task(struct rq *rq, struct task_struct *next)
@ -2353,6 +2372,30 @@ static inline void set_next_task(struct rq *rq, struct task_struct *next)
next->sched_class->set_next_task(rq, next, false);
}
static inline void
__put_prev_set_next_dl_server(struct rq *rq,
struct task_struct *prev,
struct task_struct *next)
{
prev->dl_server = NULL;
next->dl_server = rq->dl_server;
rq->dl_server = NULL;
}
static inline void put_prev_set_next_task(struct rq *rq,
struct task_struct *prev,
struct task_struct *next)
{
WARN_ON_ONCE(rq->curr != prev);
__put_prev_set_next_dl_server(rq, prev, next);
if (next == prev)
return;
prev->sched_class->put_prev_task(rq, prev, next);
next->sched_class->set_next_task(rq, next, true);
}
/*
* Helper to define a sched_class instance; each one is placed in a separate
@ -2408,7 +2451,7 @@ static inline bool sched_fair_runnable(struct rq *rq)
}
extern struct task_struct *pick_next_task_fair(struct rq *rq, struct task_struct *prev, struct rq_flags *rf);
extern struct task_struct *pick_next_task_idle(struct rq *rq);
extern struct task_struct *pick_task_idle(struct rq *rq);
#define SCA_CHECK 0x01
#define SCA_MIGRATE_DISABLE 0x02
@ -2515,7 +2558,6 @@ extern void reweight_task(struct task_struct *p, const struct load_weight *lw);
extern void resched_curr(struct rq *rq);
extern void resched_cpu(int cpu);
extern struct rt_bandwidth def_rt_bandwidth;
extern void init_rt_bandwidth(struct rt_bandwidth *rt_b, u64 period, u64 runtime);
extern bool sched_rt_bandwidth_account(struct rt_rq *rt_rq);
@ -2586,6 +2628,19 @@ static inline void sub_nr_running(struct rq *rq, unsigned count)
sched_update_tick_dependency(rq);
}
static inline void __block_task(struct rq *rq, struct task_struct *p)
{
WRITE_ONCE(p->on_rq, 0);
ASSERT_EXCLUSIVE_WRITER(p->on_rq);
if (p->sched_contributes_to_load)
rq->nr_uninterruptible++;
if (p->in_iowait) {
atomic_inc(&rq->nr_iowait);
delayacct_blkio_start();
}
}
extern void activate_task(struct rq *rq, struct task_struct *p, int flags);
extern void deactivate_task(struct rq *rq, struct task_struct *p, int flags);
@ -3607,7 +3662,7 @@ extern int __sched_setaffinity(struct task_struct *p, struct affinity_context *c
extern void __setscheduler_prio(struct task_struct *p, int prio);
extern void set_load_weight(struct task_struct *p, bool update_load);
extern void enqueue_task(struct rq *rq, struct task_struct *p, int flags);
extern void dequeue_task(struct rq *rq, struct task_struct *p, int flags);
extern bool dequeue_task(struct rq *rq, struct task_struct *p, int flags);
extern void check_class_changed(struct rq *rq, struct task_struct *p,
const struct sched_class *prev_class,

18
kernel/sched/stop_task.c
View File

@ -41,26 +41,17 @@ static struct task_struct *pick_task_stop(struct rq *rq)
return rq->stop;
}
static struct task_struct *pick_next_task_stop(struct rq *rq)
{
struct task_struct *p = pick_task_stop(rq);
if (p)
set_next_task_stop(rq, p, true);
return p;
}
static void
enqueue_task_stop(struct rq *rq, struct task_struct *p, int flags)
{
add_nr_running(rq, 1);
}
static void
static bool
dequeue_task_stop(struct rq *rq, struct task_struct *p, int flags)
{
sub_nr_running(rq, 1);
return true;
}
static void yield_task_stop(struct rq *rq)
@ -68,7 +59,7 @@ static void yield_task_stop(struct rq *rq)
BUG(); /* the stop task should never yield, its pointless. */
}
static void put_prev_task_stop(struct rq *rq, struct task_struct *prev)
static void put_prev_task_stop(struct rq *rq, struct task_struct *prev, struct task_struct *next)
{
update_curr_common(rq);
}
@ -111,13 +102,12 @@ DEFINE_SCHED_CLASS(stop) = {
.wakeup_preempt = wakeup_preempt_stop,
.pick_next_task = pick_next_task_stop,
.pick_task = pick_task_stop,
.put_prev_task = put_prev_task_stop,
.set_next_task = set_next_task_stop,
#ifdef CONFIG_SMP
.balance = balance_stop,
.pick_task = pick_task_stop,
.select_task_rq = select_task_rq_stop,
.set_cpus_allowed = set_cpus_allowed_common,
#endif

134
kernel/sched/syscalls.c
View File

@ -57,7 +57,7 @@ static int effective_prio(struct task_struct *p)
* keep the priority unchanged. Otherwise, update priority
* to the normal priority:
*/
if (!rt_prio(p->prio))
if (!rt_or_dl_prio(p->prio))
return p->normal_prio;
return p->prio;
}
@ -258,107 +258,6 @@ int sched_core_idle_cpu(int cpu)
#endif
#ifdef CONFIG_SMP
/*
* This function computes an effective utilization for the given CPU, to be
* used for frequency selection given the linear relation: f = u * f_max.
*
* The scheduler tracks the following metrics:
*
* cpu_util_{cfs,rt,dl,irq}()
* cpu_bw_dl()
*
* Where the cfs,rt and dl util numbers are tracked with the same metric and
* synchronized windows and are thus directly comparable.
*
* The cfs,rt,dl utilization are the running times measured with rq->clock_task
* which excludes things like IRQ and steal-time. These latter are then accrued
* in the IRQ utilization.
*
* The DL bandwidth number OTOH is not a measured metric but a value computed
* based on the task model parameters and gives the minimal utilization
* required to meet deadlines.
*/
unsigned long effective_cpu_util(int cpu, unsigned long util_cfs,
unsigned long *min,
unsigned long *max)
{
unsigned long util, irq, scale;
struct rq *rq = cpu_rq(cpu);
scale = arch_scale_cpu_capacity(cpu);
/*
* Early check to see if IRQ/steal time saturates the CPU, can be
* because of inaccuracies in how we track these -- see
* update_irq_load_avg().
*/
irq = cpu_util_irq(rq);
if (unlikely(irq >= scale)) {
if (min)
*min = scale;
if (max)
*max = scale;
return scale;
}
if (min) {
/*
* The minimum utilization returns the highest level between:
* - the computed DL bandwidth needed with the IRQ pressure which
* steals time to the deadline task.
* - The minimum performance requirement for CFS and/or RT.
*/
*min = max(irq + cpu_bw_dl(rq), uclamp_rq_get(rq, UCLAMP_MIN));
/*
* When an RT task is runnable and uclamp is not used, we must
* ensure that the task will run at maximum compute capacity.
*/
if (!uclamp_is_used() && rt_rq_is_runnable(&rq->rt))
*min = max(*min, scale);
}
/*
* Because the time spend on RT/DL tasks is visible as 'lost' time to
* CFS tasks and we use the same metric to track the effective
* utilization (PELT windows are synchronized) we can directly add them
* to obtain the CPU's actual utilization.
*/
util = util_cfs + cpu_util_rt(rq);
util += cpu_util_dl(rq);
/*
* The maximum hint is a soft bandwidth requirement, which can be lower
* than the actual utilization because of uclamp_max requirements.
*/
if (max)
*max = min(scale, uclamp_rq_get(rq, UCLAMP_MAX));
if (util >= scale)
return scale;
/*
* There is still idle time; further improve the number by using the
* IRQ metric. Because IRQ/steal time is hidden from the task clock we
* need to scale the task numbers:
*
* max - irq
* U' = irq + --------- * U
* max
*/
util = scale_irq_capacity(util, irq, scale);
util += irq;
return min(scale, util);
}
unsigned long sched_cpu_util(int cpu)
{
return effective_cpu_util(cpu, cpu_util_cfs(cpu), NULL, NULL);
}
#endif /* CONFIG_SMP */
/**
* find_process_by_pid - find a process with a matching PID value.
* @pid: the pid in question.
@ -401,13 +300,23 @@ static void __setscheduler_params(struct task_struct *p,
p->policy = policy;
if (dl_policy(policy))
if (dl_policy(policy)) {
__setparam_dl(p, attr);
else if (fair_policy(policy))
} else if (fair_policy(policy)) {
p->static_prio = NICE_TO_PRIO(attr->sched_nice);
if (attr->sched_runtime) {
p->se.custom_slice = 1;
p->se.slice = clamp_t(u64, attr->sched_runtime,
NSEC_PER_MSEC/10, /* HZ=1000 * 10 */
NSEC_PER_MSEC*100); /* HZ=100 / 10 */
} else {
p->se.custom_slice = 0;
p->se.slice = sysctl_sched_base_slice;
}
}
/* rt-policy tasks do not have a timerslack */
if (task_is_realtime(p)) {
if (rt_or_dl_task_policy(p)) {
p->timer_slack_ns = 0;
} else if (p->timer_slack_ns == 0) {
/* when switching back to non-rt policy, restore timerslack */
@ -708,7 +617,9 @@ int __sched_setscheduler(struct task_struct *p,
* but store a possible modification of reset_on_fork.
*/
if (unlikely(policy == p->policy)) {
if (fair_policy(policy) && attr->sched_nice != task_nice(p))
if (fair_policy(policy) &&
(attr->sched_nice != task_nice(p) ||
(attr->sched_runtime != p->se.slice)))
goto change;
if (rt_policy(policy) && attr->sched_priority != p->rt_priority)
goto change;
@ -854,6 +765,9 @@ static int _sched_setscheduler(struct task_struct *p, int policy,
.sched_nice = PRIO_TO_NICE(p->static_prio),
};
if (p->se.custom_slice)
attr.sched_runtime = p->se.slice;
/* Fixup the legacy SCHED_RESET_ON_FORK hack. */
if ((policy != SETPARAM_POLICY) && (policy & SCHED_RESET_ON_FORK)) {
attr.sched_flags |= SCHED_FLAG_RESET_ON_FORK;
@ -1020,12 +934,14 @@ static int sched_copy_attr(struct sched_attr __user *uattr, struct sched_attr *a
static void get_params(struct task_struct *p, struct sched_attr *attr)
{
if (task_has_dl_policy(p))
if (task_has_dl_policy(p)) {
__getparam_dl(p, attr);
else if (task_has_rt_policy(p))
} else if (task_has_rt_policy(p)) {
attr->sched_priority = p->rt_priority;
else
} else {
attr->sched_nice = task_nice(p);
attr->sched_runtime = p->se.slice;
}
}
/**

8
kernel/sched/topology.c
View File

@ -516,6 +516,14 @@ void rq_attach_root(struct rq *rq, struct root_domain *rd)
if (cpumask_test_cpu(rq->cpu, cpu_active_mask))
set_rq_online(rq);
/*
* Because the rq is not a task, dl_add_task_root_domain() did not
* move the fair server bw to the rd if it already started.
* Add it now.
*/
if (rq->fair_server.dl_server)
__dl_server_attach_root(&rq->fair_server, rq);
rq_unlock_irqrestore(rq, &rf);
if (old_rd)

2
kernel/sys.c
View File

@ -2557,7 +2557,7 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
error = current->timer_slack_ns;
break;
case PR_SET_TIMERSLACK:
if (task_is_realtime(current))
if (rt_or_dl_task_policy(current))
break;
if (arg2 <= 0)
current->timer_slack_ns =

2
kernel/time/hrtimer.c
View File

@ -1977,7 +1977,7 @@ static void __hrtimer_init_sleeper(struct hrtimer_sleeper *sl,
* expiry.
*/
if (IS_ENABLED(CONFIG_PREEMPT_RT)) {
if (task_is_realtime(current) && !(mode & HRTIMER_MODE_SOFT))
if (rt_or_dl_task_policy(current) && !(mode & HRTIMER_MODE_SOFT))
mode |= HRTIMER_MODE_HARD;
}

2
kernel/trace/trace_sched_wakeup.c
View File

@ -547,7 +547,7 @@ probe_wakeup(void *ignore, struct task_struct *p)
* - wakeup_dl handles tasks belonging to sched_dl class only.
*/
if (tracing_dl || (wakeup_dl && !dl_task(p)) ||
(wakeup_rt && !dl_task(p) && !rt_task(p)) ||
(wakeup_rt && !rt_or_dl_task(p)) ||
(!dl_task(p) && (p->prio >= wakeup_prio || p->prio >= current->prio)))
return;

4
mm/page-writeback.c
View File

@ -418,7 +418,7 @@ static void domain_dirty_limits(struct dirty_throttle_control *dtc)
bg_thresh = (bg_ratio * available_memory) / PAGE_SIZE;
tsk = current;
if (rt_task(tsk)) {
if (rt_or_dl_task(tsk)) {
bg_thresh += bg_thresh / 4 + global_wb_domain.dirty_limit / 32;
thresh += thresh / 4 + global_wb_domain.dirty_limit / 32;
}
@ -477,7 +477,7 @@ static unsigned long node_dirty_limit(struct pglist_data *pgdat)
else
dirty = vm_dirty_ratio * node_memory / 100;
if (rt_task(tsk))
if (rt_or_dl_task(tsk))
dirty += dirty / 4;
/*

2
mm/page_alloc.c
View File

@ -4004,7 +4004,7 @@ gfp_to_alloc_flags(gfp_t gfp_mask, unsigned int order)
*/
if (alloc_flags & ALLOC_MIN_RESERVE)
alloc_flags &= ~ALLOC_CPUSET;
} else if (unlikely(rt_task(current)) && in_task())
} else if (unlikely(rt_or_dl_task(current)) && in_task())
alloc_flags |= ALLOC_MIN_RESERVE;
alloc_flags = gfp_to_alloc_flags_cma(gfp_mask, alloc_flags);