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Merge branch 'tip/sched/core' into sched_ext/for-6.12

Browse source 
Pull in tip/sched/core to resolve two merge conflicts:

- 96fd6c65ef ("sched: Factor out update_other_load_avgs() from __update_blocked_others()")
  5d871a6399 ("sched/fair: Move effective_cpu_util() and effective_cpu_util() in fair.c")

  A simple context conflict. The former added __update_blocked_others() in
  the same #ifdef CONFIG_SMP block that effective_cpu_util() and
  sched_cpu_util() are in and the latter moved those functions to fair.c.
  This makes __update_blocked_others() more out of place. Will follow up
  with a patch to relocate.

- 96fd6c65ef ("sched: Factor out update_other_load_avgs() from __update_blocked_others()")
  84d265281d ("sched/pelt: Use rq_clock_task() for hw_pressure")

  The former factored out the body of __update_blocked_others() into
  update_other_load_avgs(). The latter changed how update_hw_load_avg() is
  called in the body. Resolved by applying the change to
  update_other_load_avgs() instead.

Signed-off-by: Tejun Heo <tj@kernel.org>
This commit is contained in:
Tejun Heo 2024-09-11 08:43:26 -10:00
commit 0b1777f0fa
9 changed files with 189 additions and 152 deletions
repo.diff.show_diff_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;

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

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();

51
kernel/sched/core.c
View file

@ -267,6 +267,9 @@ 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)
@ -277,6 +280,9 @@ 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)) {
@ -6477,19 +6483,12 @@ 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.
@ -6530,9 +6529,14 @@ 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;
@ -6543,13 +6547,13 @@ 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
@ -6578,12 +6582,20 @@ 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 {
@ -6614,6 +6626,7 @@ static void __sched notrace __schedule(unsigned int sched_mode)
}
next = pick_next_task(rq, prev, &rf);
picked:
clear_tsk_need_resched(prev);
clear_preempt_need_resched();
#ifdef CONFIG_SCHED_DEBUG
@ -6655,7 +6668,7 @@ 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);
@ -6731,7 +6744,7 @@ 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();
@ -6776,7 +6789,7 @@ void __sched schedule_idle(void)
*/
WARN_ON_ONCE(current->__state);
do {
__schedule(SM_NONE);
__schedule(SM_IDLE);
} while (need_resched());
}

6
kernel/sched/cpufreq_schedutil.c
View file

@ -662,9 +662,9 @@ 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;

31
kernel/sched/debug.c
View file

@ -739,7 +739,7 @@ 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 %c %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',
@ -750,17 +750,16 @@ print_task(struct seq_file *m, struct rq *rq, struct task_struct *p)
(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");
@ -772,10 +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) {

115
kernel/sched/fair.c
View file

@ -6949,18 +6949,19 @@ enqueue_task_fair(struct rq *rq, struct task_struct *p, int flags)
int rq_h_nr_running = rq->cfs.h_nr_running;
u64 slice = 0;
if (flags & ENQUEUE_DELAYED) {
requeue_delayed_entity(se);
return;
}
/*
* The code below (indirectly) updates schedutil which looks at
* the cfs_rq utilization to select a frequency.
* Let's add the task's estimated utilization to the cfs_rq's
* estimated utilization, before we update schedutil.
*/
util_est_enqueue(&rq->cfs, p);
if (!(p->se.sched_delayed && (task_on_rq_migrating(p) || (flags & ENQUEUE_RESTORE))))
util_est_enqueue(&rq->cfs, p);
if (flags & ENQUEUE_DELAYED) {
requeue_delayed_entity(se);
return;
}
/*
* If in_iowait is set, the code below may not trigger any cpufreq
@ -7178,7 +7179,8 @@ static int dequeue_entities(struct rq *rq, struct sched_entity *se, int flags)
*/
static bool dequeue_task_fair(struct rq *rq, struct task_struct *p, int flags)
{
util_est_dequeue(&rq->cfs, p);
if (!(p->se.sched_delayed && (task_on_rq_migrating(p) || (flags & DEQUEUE_SAVE))))
util_est_dequeue(&rq->cfs, p);
if (dequeue_entities(rq, &p->se, flags) < 0) {
util_est_update(&rq->cfs, p, DEQUEUE_SLEEP);
@ -8085,6 +8087,105 @@ static unsigned long cpu_util_without(int cpu, struct task_struct *p)
return cpu_util(cpu, p, -1, 0);
}
/*
* 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);
}
/*
* energy_env - Utilization landscape for energy estimation.
* @task_busy_time: Utilization contribution by the task for which we test the

102
kernel/sched/syscalls.c
View file

@ -272,110 +272,12 @@ bool update_other_load_avgs(struct rq *rq)
lockdep_assert_rq_held(rq);
/* hw_pressure doesn't care about invariance */
return update_rt_rq_load_avg(now, rq, curr_class == &rt_sched_class) |
update_dl_rq_load_avg(now, rq, curr_class == &dl_sched_class) |
update_hw_load_avg(now, rq, hw_pressure) |
update_hw_load_avg(rq_clock_task(rq), rq, hw_pressure) |
update_irq_load_avg(rq, 0);
}
/*
* 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 */
/**