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linux/kernel/sched/sched.h
Mathias Krause b027789e5e sched/fair: Prevent dead task groups from regaining cfs_rq's 
Kevin is reporting crashes which point to a use-after-free of a cfs_rq
in update_blocked_averages(). Initial debugging revealed that we've
live cfs_rq's (on_list=1) in an about to be kfree()'d task group in
free_fair_sched_group(). However, it was unclear how that can happen.

His kernel config happened to lead to a layout of struct sched_entity
that put the 'my_q' member directly into the middle of the object
which makes it incidentally overlap with SLUB's freelist pointer.
That, in combination with SLAB_FREELIST_HARDENED's freelist pointer
mangling, leads to a reliable access violation in form of a #GP which
made the UAF fail fast.

Michal seems to have run into the same issue[1]. He already correctly
diagnosed that commit a7b359fc6a ("sched/fair: Correctly insert
cfs_rq's to list on unthrottle") is causing the preconditions for the
UAF to happen by re-adding cfs_rq's also to task groups that have no
more running tasks, i.e. also to dead ones. His analysis, however,
misses the real root cause and it cannot be seen from the crash
backtrace only, as the real offender is tg_unthrottle_up() getting
called via sched_cfs_period_timer() via the timer interrupt at an
inconvenient time.

When unregister_fair_sched_group() unlinks all cfs_rq's from the dying
task group, it doesn't protect itself from getting interrupted. If the
timer interrupt triggers while we iterate over all CPUs or after
unregister_fair_sched_group() has finished but prior to unlinking the
task group, sched_cfs_period_timer() will execute and walk the list of
task groups, trying to unthrottle cfs_rq's, i.e. re-add them to the
dying task group. These will later -- in free_fair_sched_group() -- be
kfree()'ed while still being linked, leading to the fireworks Kevin
and Michal are seeing.

To fix this race, ensure the dying task group gets unlinked first.
However, simply switching the order of unregistering and unlinking the
task group isn't sufficient, as concurrent RCU walkers might still see
it, as can be seen below:

    CPU1:                                      CPU2:
      :                                        timer IRQ:
      :                                          do_sched_cfs_period_timer():
      :                                            :
      :                                            distribute_cfs_runtime():
      :                                              rcu_read_lock();
      :                                              :
      :                                              unthrottle_cfs_rq():
    sched_offline_group():                             :
      :                                                walk_tg_tree_from(…,tg_unthrottle_up,…):
      list_del_rcu(&tg->list);                           :
 (1)  :                                                  list_for_each_entry_rcu(child, &parent->children, siblings)
      :                                                    :
 (2)  list_del_rcu(&tg->siblings);                         :
      :                                                    tg_unthrottle_up():
      unregister_fair_sched_group():                         struct cfs_rq *cfs_rq = tg->cfs_rq[cpu_of(rq)];
        :                                                    :
        list_del_leaf_cfs_rq(tg->cfs_rq[cpu]);               :
        :                                                    :
        :                                                    if (!cfs_rq_is_decayed(cfs_rq) || cfs_rq->nr_running)
 (3)    :                                                        list_add_leaf_cfs_rq(cfs_rq);
      :                                                      :
      :                                                    :
      :                                                  :
      :                                                :
      :                                              :
 (4)  :                                              rcu_read_unlock();

CPU 2 walks the task group list in parallel to sched_offline_group(),
specifically, it'll read the soon to be unlinked task group entry at
(1). Unlinking it on CPU 1 at (2) therefore won't prevent CPU 2 from
still passing it on to tg_unthrottle_up(). CPU 1 now tries to unlink
all cfs_rq's via list_del_leaf_cfs_rq() in
unregister_fair_sched_group().  Meanwhile CPU 2 will re-add some of
these at (3), which is the cause of the UAF later on.

To prevent this additional race from happening, we need to wait until
walk_tg_tree_from() has finished traversing the task groups, i.e.
after the RCU read critical section ends in (4). Afterwards we're safe
to call unregister_fair_sched_group(), as each new walk won't see the
dying task group any more.

On top of that, we need to wait yet another RCU grace period after
unregister_fair_sched_group() to ensure print_cfs_stats(), which might
run concurrently, always sees valid objects, i.e. not already free'd
ones.

This patch survives Michal's reproducer[2] for 8h+ now, which used to
trigger within minutes before.

  [1] https://lore.kernel.org/lkml/20211011172236.11223-1-mkoutny@suse.com/
  [2] https://lore.kernel.org/lkml/20211102160228.GA57072@blackbody.suse.cz/

Fixes: a7b359fc6a ("sched/fair: Correctly insert cfs_rq's to list on unthrottle")
[peterz: shuffle code around a bit]
Reported-by: Kevin Tanguy <kevin.tanguy@corp.ovh.com>
Signed-off-by: Mathias Krause <minipli@grsecurity.net>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
2021-11-11 13:09:33 +01:00

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/* SPDX-License-Identifier: GPL-2.0 */
/*
* Scheduler internal types and methods:
*/
#include <linux/sched.h>
#include <linux/sched/autogroup.h>
#include <linux/sched/clock.h>
#include <linux/sched/coredump.h>
#include <linux/sched/cpufreq.h>
#include <linux/sched/cputime.h>
#include <linux/sched/deadline.h>
#include <linux/sched/debug.h>
#include <linux/sched/hotplug.h>
#include <linux/sched/idle.h>
#include <linux/sched/init.h>
#include <linux/sched/isolation.h>
#include <linux/sched/jobctl.h>
#include <linux/sched/loadavg.h>
#include <linux/sched/mm.h>
#include <linux/sched/nohz.h>
#include <linux/sched/numa_balancing.h>
#include <linux/sched/prio.h>
#include <linux/sched/rt.h>
#include <linux/sched/signal.h>
#include <linux/sched/smt.h>
#include <linux/sched/stat.h>
#include <linux/sched/sysctl.h>
#include <linux/sched/task.h>
#include <linux/sched/task_stack.h>
#include <linux/sched/topology.h>
#include <linux/sched/user.h>
#include <linux/sched/wake_q.h>
#include <linux/sched/xacct.h>
#include <uapi/linux/sched/types.h>
#include <linux/binfmts.h>
#include <linux/bitops.h>
#include <linux/compat.h>
#include <linux/context_tracking.h>
#include <linux/cpufreq.h>
#include <linux/cpuidle.h>
#include <linux/cpuset.h>
#include <linux/ctype.h>
#include <linux/debugfs.h>
#include <linux/delayacct.h>
#include <linux/energy_model.h>
#include <linux/init_task.h>
#include <linux/kprobes.h>
#include <linux/kthread.h>
#include <linux/membarrier.h>
#include <linux/migrate.h>
#include <linux/mmu_context.h>
#include <linux/nmi.h>
#include <linux/proc_fs.h>
#include <linux/prefetch.h>
#include <linux/profile.h>
#include <linux/psi.h>
#include <linux/ratelimit.h>
#include <linux/rcupdate_wait.h>
#include <linux/security.h>
#include <linux/stop_machine.h>
#include <linux/suspend.h>
#include <linux/swait.h>
#include <linux/syscalls.h>
#include <linux/task_work.h>
#include <linux/tsacct_kern.h>
#include <asm/tlb.h>
#ifdef CONFIG_PARAVIRT
# include <asm/paravirt.h>
#endif
#include "cpupri.h"
#include "cpudeadline.h"
#include <trace/events/sched.h>
#ifdef CONFIG_SCHED_DEBUG
# define SCHED_WARN_ON(x) WARN_ONCE(x, #x)
#else
# define SCHED_WARN_ON(x) ({ (void)(x), 0; })
#endif
struct rq;
struct cpuidle_state;
/* task_struct::on_rq states: */
#define TASK_ON_RQ_QUEUED 1
#define TASK_ON_RQ_MIGRATING 2
extern __read_mostly int scheduler_running;
extern unsigned long calc_load_update;
extern atomic_long_t calc_load_tasks;
extern void calc_global_load_tick(struct rq *this_rq);
extern long calc_load_fold_active(struct rq *this_rq, long adjust);
extern void call_trace_sched_update_nr_running(struct rq *rq, int count);
/*
* Helpers for converting nanosecond timing to jiffy resolution
*/
#define NS_TO_JIFFIES(TIME) ((unsigned long)(TIME) / (NSEC_PER_SEC / HZ))
/*
* Increase resolution of nice-level calculations for 64-bit architectures.
* The extra resolution improves shares distribution and load balancing of
* low-weight task groups (eg. nice +19 on an autogroup), deeper taskgroup
* hierarchies, especially on larger systems. This is not a user-visible change
* and does not change the user-interface for setting shares/weights.
*
* We increase resolution only if we have enough bits to allow this increased
* resolution (i.e. 64-bit). The costs for increasing resolution when 32-bit
* are pretty high and the returns do not justify the increased costs.
*
* Really only required when CONFIG_FAIR_GROUP_SCHED=y is also set, but to
* increase coverage and consistency always enable it on 64-bit platforms.
*/
#ifdef CONFIG_64BIT
# define NICE_0_LOAD_SHIFT (SCHED_FIXEDPOINT_SHIFT + SCHED_FIXEDPOINT_SHIFT)
# define scale_load(w) ((w) << SCHED_FIXEDPOINT_SHIFT)
# define scale_load_down(w) \
({ \
unsigned long __w = (w); \
if (__w) \
__w = max(2UL, __w >> SCHED_FIXEDPOINT_SHIFT); \
__w; \
})
#else
# define NICE_0_LOAD_SHIFT (SCHED_FIXEDPOINT_SHIFT)
# define scale_load(w) (w)
# define scale_load_down(w) (w)
#endif
/*
* Task weight (visible to users) and its load (invisible to users) have
* independent resolution, but they should be well calibrated. We use
* scale_load() and scale_load_down(w) to convert between them. The
* following must be true:
*
* scale_load(sched_prio_to_weight[NICE_TO_PRIO(0)-MAX_RT_PRIO]) == NICE_0_LOAD
*
*/
#define NICE_0_LOAD (1L << NICE_0_LOAD_SHIFT)
/*
* Single value that decides SCHED_DEADLINE internal math precision.
* 10 -> just above 1us
* 9 -> just above 0.5us
*/
#define DL_SCALE 10
/*
* Single value that denotes runtime == period, ie unlimited time.
*/
#define RUNTIME_INF ((u64)~0ULL)
static inline int idle_policy(int policy)
{
return policy == SCHED_IDLE;
}
static inline int fair_policy(int policy)
{
return policy == SCHED_NORMAL || policy == SCHED_BATCH;
}
static inline int rt_policy(int policy)
{
return policy == SCHED_FIFO || policy == SCHED_RR;
}
static inline int dl_policy(int policy)
{
return policy == SCHED_DEADLINE;
}
static inline bool valid_policy(int policy)
{
return idle_policy(policy) || fair_policy(policy) ||
rt_policy(policy) || dl_policy(policy);
}
static inline int task_has_idle_policy(struct task_struct *p)
{
return idle_policy(p->policy);
}
static inline int task_has_rt_policy(struct task_struct *p)
{
return rt_policy(p->policy);
}
static inline int task_has_dl_policy(struct task_struct *p)
{
return dl_policy(p->policy);
}
#define cap_scale(v, s) ((v)*(s) >> SCHED_CAPACITY_SHIFT)
static inline void update_avg(u64 *avg, u64 sample)
{
s64 diff = sample - *avg;
*avg += diff / 8;
}
/*
* Shifting a value by an exponent greater *or equal* to the size of said value
* is UB; cap at size-1.
*/
#define shr_bound(val, shift) \
(val >> min_t(typeof(shift), shift, BITS_PER_TYPE(typeof(val)) - 1))
/*
* !! For sched_setattr_nocheck() (kernel) only !!
*
* This is actually gross. :(
*
* It is used to make schedutil kworker(s) higher priority than SCHED_DEADLINE
* tasks, but still be able to sleep. We need this on platforms that cannot
* atomically change clock frequency. Remove once fast switching will be
* available on such platforms.
*
* SUGOV stands for SchedUtil GOVernor.
*/
#define SCHED_FLAG_SUGOV 0x10000000
#define SCHED_DL_FLAGS (SCHED_FLAG_RECLAIM | SCHED_FLAG_DL_OVERRUN | SCHED_FLAG_SUGOV)
static inline bool dl_entity_is_special(struct sched_dl_entity *dl_se)
{
#ifdef CONFIG_CPU_FREQ_GOV_SCHEDUTIL
return unlikely(dl_se->flags & SCHED_FLAG_SUGOV);
#else
return false;
#endif
}
/*
* Tells if entity @a should preempt entity @b.
*/
static inline bool
dl_entity_preempt(struct sched_dl_entity *a, struct sched_dl_entity *b)
{
return dl_entity_is_special(a) ||
dl_time_before(a->deadline, b->deadline);
}
/*
* This is the priority-queue data structure of the RT scheduling class:
*/
struct rt_prio_array {
DECLARE_BITMAP(bitmap, MAX_RT_PRIO+1); /* include 1 bit for delimiter */
struct list_head queue[MAX_RT_PRIO];
};
struct rt_bandwidth {
/* nests inside the rq lock: */
raw_spinlock_t rt_runtime_lock;
ktime_t rt_period;
u64 rt_runtime;
struct hrtimer rt_period_timer;
unsigned int rt_period_active;
};
void __dl_clear_params(struct task_struct *p);
struct dl_bandwidth {
raw_spinlock_t dl_runtime_lock;
u64 dl_runtime;
u64 dl_period;
};
static inline int dl_bandwidth_enabled(void)
{
return sysctl_sched_rt_runtime >= 0;
}
/*
* To keep the bandwidth of -deadline tasks under control
* we need some place where:
* - store the maximum -deadline bandwidth of each cpu;
* - cache the fraction of bandwidth that is currently allocated in
* each root domain;
*
* This is all done in the data structure below. It is similar to the
* one used for RT-throttling (rt_bandwidth), with the main difference
* that, since here we are only interested in admission control, we
* do not decrease any runtime while the group "executes", neither we
* need a timer to replenish it.
*
* With respect to SMP, bandwidth is given on a per root domain basis,
* meaning that:
* - bw (< 100%) is the deadline bandwidth of each CPU;
* - total_bw is the currently allocated bandwidth in each root domain;
*/
struct dl_bw {
raw_spinlock_t lock;
u64 bw;
u64 total_bw;
};
static inline void __dl_update(struct dl_bw *dl_b, s64 bw);
static inline
void __dl_sub(struct dl_bw *dl_b, u64 tsk_bw, int cpus)
{
dl_b->total_bw -= tsk_bw;
__dl_update(dl_b, (s32)tsk_bw / cpus);
}
static inline
void __dl_add(struct dl_bw *dl_b, u64 tsk_bw, int cpus)
{
dl_b->total_bw += tsk_bw;
__dl_update(dl_b, -((s32)tsk_bw / cpus));
}
static inline bool __dl_overflow(struct dl_bw *dl_b, unsigned long cap,
u64 old_bw, u64 new_bw)
{
return dl_b->bw != -1 &&
cap_scale(dl_b->bw, cap) < dl_b->total_bw - old_bw + new_bw;
}
/*
* Verify the fitness of task @p to run on @cpu taking into account the
* CPU original capacity and the runtime/deadline ratio of the task.
*
* The function will return true if the CPU original capacity of the
* @cpu scaled by SCHED_CAPACITY_SCALE >= runtime/deadline ratio of the
* task and false otherwise.
*/
static inline bool dl_task_fits_capacity(struct task_struct *p, int cpu)
{
unsigned long cap = arch_scale_cpu_capacity(cpu);
return cap_scale(p->dl.dl_deadline, cap) >= p->dl.dl_runtime;
}
extern void init_dl_bw(struct dl_bw *dl_b);
extern int sched_dl_global_validate(void);
extern void sched_dl_do_global(void);
extern int sched_dl_overflow(struct task_struct *p, int policy, const struct sched_attr *attr);
extern void __setparam_dl(struct task_struct *p, const struct sched_attr *attr);
extern void __getparam_dl(struct task_struct *p, struct sched_attr *attr);
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_task_can_attach(struct task_struct *p, const struct cpumask *cs_cpus_allowed);
extern int dl_cpuset_cpumask_can_shrink(const struct cpumask *cur, const struct cpumask *trial);
extern bool dl_cpu_busy(unsigned int cpu);
#ifdef CONFIG_CGROUP_SCHED
#include <linux/cgroup.h>
#include <linux/psi.h>
struct cfs_rq;
struct rt_rq;
extern struct list_head task_groups;
struct cfs_bandwidth {
#ifdef CONFIG_CFS_BANDWIDTH
raw_spinlock_t lock;
ktime_t period;
u64 quota;
u64 runtime;
u64 burst;
u64 runtime_snap;
s64 hierarchical_quota;
u8 idle;
u8 period_active;
u8 slack_started;
struct hrtimer period_timer;
struct hrtimer slack_timer;
struct list_head throttled_cfs_rq;
/* Statistics: */
int nr_periods;
int nr_throttled;
int nr_burst;
u64 throttled_time;
u64 burst_time;
#endif
};
/* Task group related information */
struct task_group {
struct cgroup_subsys_state css;
#ifdef CONFIG_FAIR_GROUP_SCHED
/* schedulable entities of this group on each CPU */
struct sched_entity **se;
/* runqueue "owned" by this group on each CPU */
struct cfs_rq **cfs_rq;
unsigned long shares;
/* A positive value indicates that this is a SCHED_IDLE group. */
int idle;
#ifdef CONFIG_SMP
/*
* load_avg can be heavily contended at clock tick time, so put
* it in its own cacheline separated from the fields above which
* will also be accessed at each tick.
*/
atomic_long_t load_avg ____cacheline_aligned;
#endif
#endif
#ifdef CONFIG_RT_GROUP_SCHED
struct sched_rt_entity **rt_se;
struct rt_rq **rt_rq;
struct rt_bandwidth rt_bandwidth;
#endif
struct rcu_head rcu;
struct list_head list;
struct task_group *parent;
struct list_head siblings;
struct list_head children;
#ifdef CONFIG_SCHED_AUTOGROUP
struct autogroup *autogroup;
#endif
struct cfs_bandwidth cfs_bandwidth;
#ifdef CONFIG_UCLAMP_TASK_GROUP
/* The two decimal precision [%] value requested from user-space */
unsigned int uclamp_pct[UCLAMP_CNT];
/* Clamp values requested for a task group */
struct uclamp_se uclamp_req[UCLAMP_CNT];
/* Effective clamp values used for a task group */
struct uclamp_se uclamp[UCLAMP_CNT];
#endif
};
#ifdef CONFIG_FAIR_GROUP_SCHED
#define ROOT_TASK_GROUP_LOAD NICE_0_LOAD
/*
* A weight of 0 or 1 can cause arithmetics problems.
* A weight of a cfs_rq is the sum of weights of which entities
* are queued on this cfs_rq, so a weight of a entity should not be
* too large, so as the shares value of a task group.
* (The default weight is 1024 - so there's no practical
* limitation from this.)
*/
#define MIN_SHARES (1UL << 1)
#define MAX_SHARES (1UL << 18)
#endif
typedef int (*tg_visitor)(struct task_group *, void *);
extern int walk_tg_tree_from(struct task_group *from,
tg_visitor down, tg_visitor up, void *data);
/*
* Iterate the full tree, calling @down when first entering a node and @up when
* leaving it for the final time.
*
* Caller must hold rcu_lock or sufficient equivalent.
*/
static inline int walk_tg_tree(tg_visitor down, tg_visitor up, void *data)
{
return walk_tg_tree_from(&root_task_group, down, up, data);
}
extern int tg_nop(struct task_group *tg, void *data);
extern void free_fair_sched_group(struct task_group *tg);
extern int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent);
extern void online_fair_sched_group(struct task_group *tg);
extern void unregister_fair_sched_group(struct task_group *tg);
extern void init_tg_cfs_entry(struct task_group *tg, struct cfs_rq *cfs_rq,
struct sched_entity *se, int cpu,
struct sched_entity *parent);
extern void init_cfs_bandwidth(struct cfs_bandwidth *cfs_b);
extern void __refill_cfs_bandwidth_runtime(struct cfs_bandwidth *cfs_b);
extern void start_cfs_bandwidth(struct cfs_bandwidth *cfs_b);
extern void unthrottle_cfs_rq(struct cfs_rq *cfs_rq);
extern void unregister_rt_sched_group(struct task_group *tg);
extern void free_rt_sched_group(struct task_group *tg);
extern int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent);
extern void init_tg_rt_entry(struct task_group *tg, struct rt_rq *rt_rq,
struct sched_rt_entity *rt_se, int cpu,
struct sched_rt_entity *parent);
extern int sched_group_set_rt_runtime(struct task_group *tg, long rt_runtime_us);
extern int sched_group_set_rt_period(struct task_group *tg, u64 rt_period_us);
extern long sched_group_rt_runtime(struct task_group *tg);
extern long sched_group_rt_period(struct task_group *tg);
extern int sched_rt_can_attach(struct task_group *tg, struct task_struct *tsk);
extern struct task_group *sched_create_group(struct task_group *parent);
extern void sched_online_group(struct task_group *tg,
struct task_group *parent);
extern void sched_destroy_group(struct task_group *tg);
extern void sched_release_group(struct task_group *tg);
extern void sched_move_task(struct task_struct *tsk);
#ifdef CONFIG_FAIR_GROUP_SCHED
extern int sched_group_set_shares(struct task_group *tg, unsigned long shares);
extern int sched_group_set_idle(struct task_group *tg, long idle);
#ifdef CONFIG_SMP
extern void set_task_rq_fair(struct sched_entity *se,
struct cfs_rq *prev, struct cfs_rq *next);
#else /* !CONFIG_SMP */
static inline void set_task_rq_fair(struct sched_entity *se,
struct cfs_rq *prev, struct cfs_rq *next) { }
#endif /* CONFIG_SMP */
#endif /* CONFIG_FAIR_GROUP_SCHED */
#else /* CONFIG_CGROUP_SCHED */
struct cfs_bandwidth { };
#endif /* CONFIG_CGROUP_SCHED */
/* CFS-related fields in a runqueue */
struct cfs_rq {
struct load_weight load;
unsigned int nr_running;
unsigned int h_nr_running; /* SCHED_{NORMAL,BATCH,IDLE} */
unsigned int idle_nr_running; /* SCHED_IDLE */
unsigned int idle_h_nr_running; /* SCHED_IDLE */
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;
/*
* 'curr' points to currently running entity on this cfs_rq.
* It is set to NULL otherwise (i.e when none are currently running).
*/
struct sched_entity *curr;
struct sched_entity *next;
struct sched_entity *last;
struct sched_entity *skip;
#ifdef CONFIG_SCHED_DEBUG
unsigned int nr_spread_over;
#endif
#ifdef CONFIG_SMP
/*
* CFS load tracking
*/
struct sched_avg avg;
#ifndef CONFIG_64BIT
u64 load_last_update_time_copy;
#endif
struct {
raw_spinlock_t lock ____cacheline_aligned;
int nr;
unsigned long load_avg;
unsigned long util_avg;
unsigned long runnable_avg;
} removed;
#ifdef CONFIG_FAIR_GROUP_SCHED
unsigned long tg_load_avg_contrib;
long propagate;
long prop_runnable_sum;
/*
* h_load = weight * f(tg)
*
* Where f(tg) is the recursive weight fraction assigned to
* this group.
*/
unsigned long h_load;
u64 last_h_load_update;
struct sched_entity *h_load_next;
#endif /* CONFIG_FAIR_GROUP_SCHED */
#endif /* CONFIG_SMP */
#ifdef CONFIG_FAIR_GROUP_SCHED
struct rq *rq; /* CPU runqueue to which this cfs_rq is attached */
/*
* leaf cfs_rqs are those that hold tasks (lowest schedulable entity in
* a hierarchy). Non-leaf lrqs hold other higher schedulable entities
* (like users, containers etc.)
*
* leaf_cfs_rq_list ties together list of leaf cfs_rq's in a CPU.
* This list is used during load balance.
*/
int on_list;
struct list_head leaf_cfs_rq_list;
struct task_group *tg; /* group that "owns" this runqueue */
/* Locally cached copy of our task_group's idle value */
int idle;
#ifdef CONFIG_CFS_BANDWIDTH
int runtime_enabled;
s64 runtime_remaining;
u64 throttled_clock;
u64 throttled_clock_task;
u64 throttled_clock_task_time;
int throttled;
int throttle_count;
struct list_head throttled_list;
#endif /* CONFIG_CFS_BANDWIDTH */
#endif /* CONFIG_FAIR_GROUP_SCHED */
};
static inline int rt_bandwidth_enabled(void)
{
return sysctl_sched_rt_runtime >= 0;
}
/* RT IPI pull logic requires IRQ_WORK */
#if defined(CONFIG_IRQ_WORK) && defined(CONFIG_SMP)
# define HAVE_RT_PUSH_IPI
#endif
/* Real-Time classes' related field in a runqueue: */
struct rt_rq {
struct rt_prio_array active;
unsigned int rt_nr_running;
unsigned int rr_nr_running;
#if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
struct {
int curr; /* highest queued rt task prio */
#ifdef CONFIG_SMP
int next; /* next highest */
#endif
} highest_prio;
#endif
#ifdef CONFIG_SMP
unsigned int rt_nr_migratory;
unsigned int rt_nr_total;
int overloaded;
struct plist_head pushable_tasks;
#endif /* CONFIG_SMP */
int rt_queued;
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;
struct task_group *tg;
#endif
};
static inline bool rt_rq_is_runnable(struct rt_rq *rt_rq)
{
return rt_rq->rt_queued && rt_rq->rt_nr_running;
}
/* Deadline class' related fields in a runqueue */
struct dl_rq {
/* runqueue is an rbtree, ordered by deadline */
struct rb_root_cached root;
unsigned int dl_nr_running;
#ifdef CONFIG_SMP
/*
* Deadline values of the currently executing and the
* earliest ready task on this rq. Caching these facilitates
* the decision whether or not a ready but not running task
* should migrate somewhere else.
*/
struct {
u64 curr;
u64 next;
} earliest_dl;
unsigned int dl_nr_migratory;
int overloaded;
/*
* Tasks on this rq that can be pushed away. They are kept in
* an rb-tree, ordered by tasks' deadlines, with caching
* of the leftmost (earliest deadline) element.
*/
struct rb_root_cached pushable_dl_tasks_root;
#else
struct dl_bw dl_bw;
#endif
/*
* "Active utilization" for this runqueue: increased when a
* task wakes up (becomes TASK_RUNNING) and decreased when a
* task blocks
*/
u64 running_bw;
/*
* Utilization of the tasks "assigned" to this runqueue (including
* the tasks that are in runqueue and the tasks that executed on this
* CPU and blocked). Increased when a task moves to this runqueue, and
* decreased when the task moves away (migrates, changes scheduling
* policy, or terminates).
* This is needed to compute the "inactive utilization" for the
* runqueue (inactive utilization = this_bw - running_bw).
*/
u64 this_bw;
u64 extra_bw;
/*
* Inverse of the fraction of CPU utilization that can be reclaimed
* by the GRUB algorithm.
*/
u64 bw_ratio;
};
#ifdef CONFIG_FAIR_GROUP_SCHED
/* An entity is a task if it doesn't "own" a runqueue */
#define entity_is_task(se) (!se->my_q)
static inline void se_update_runnable(struct sched_entity *se)
{
if (!entity_is_task(se))
se->runnable_weight = se->my_q->h_nr_running;
}
static inline long se_runnable(struct sched_entity *se)
{
if (entity_is_task(se))
return !!se->on_rq;
else
return se->runnable_weight;
}
#else
#define entity_is_task(se) 1
static inline void se_update_runnable(struct sched_entity *se) {}
static inline long se_runnable(struct sched_entity *se)
{
return !!se->on_rq;
}
#endif
#ifdef CONFIG_SMP
/*
* XXX we want to get rid of these helpers and use the full load resolution.
*/
static inline long se_weight(struct sched_entity *se)
{
return scale_load_down(se->load.weight);
}
static inline bool sched_asym_prefer(int a, int b)
{
return arch_asym_cpu_priority(a) > arch_asym_cpu_priority(b);
}
struct perf_domain {
struct em_perf_domain *em_pd;
struct perf_domain *next;
struct rcu_head rcu;
};
/* Scheduling group status flags */
#define SG_OVERLOAD 0x1 /* More than one runnable task on a CPU. */
#define SG_OVERUTILIZED 0x2 /* One or more CPUs are over-utilized. */
/*
* We add the notion of a root-domain which will be used to define per-domain
* variables. Each exclusive cpuset essentially defines an island domain by
* fully partitioning the member CPUs from any other cpuset. Whenever a new
* exclusive cpuset is created, we also create and attach a new root-domain
* object.
*
*/
struct root_domain {
atomic_t refcount;
atomic_t rto_count;
struct rcu_head rcu;
cpumask_var_t span;
cpumask_var_t online;
/*
* Indicate pullable load on at least one CPU, e.g:
* - More than one runnable task
* - Running task is misfit
*/
int overload;
/* Indicate one or more cpus over-utilized (tipping point) */
int overutilized;
/*
* The bit corresponding to a CPU gets set here if such CPU has more
* than one runnable -deadline task (as it is below for RT tasks).
*/
cpumask_var_t dlo_mask;
atomic_t dlo_count;
struct dl_bw dl_bw;
struct cpudl cpudl;
/*
* Indicate whether a root_domain's dl_bw has been checked or
* updated. It's monotonously increasing value.
*
* Also, some corner cases, like 'wrap around' is dangerous, but given
* that u64 is 'big enough'. So that shouldn't be a concern.
*/
u64 visit_gen;
#ifdef HAVE_RT_PUSH_IPI
/*
* For IPI pull requests, loop across the rto_mask.
*/
struct irq_work rto_push_work;
raw_spinlock_t rto_lock;
/* These are only updated and read within rto_lock */
int rto_loop;
int rto_cpu;
/* These atomics are updated outside of a lock */
atomic_t rto_loop_next;
atomic_t rto_loop_start;
#endif
/*
* The "RT overload" flag: it gets set if a CPU has more than
* one runnable RT task.
*/
cpumask_var_t rto_mask;
struct cpupri cpupri;
unsigned long max_cpu_capacity;
/*
* NULL-terminated list of performance domains intersecting with the
* CPUs of the rd. Protected by RCU.
*/
struct perf_domain __rcu *pd;
};
extern void init_defrootdomain(void);
extern int sched_init_domains(const struct cpumask *cpu_map);
extern void rq_attach_root(struct rq *rq, struct root_domain *rd);
extern void sched_get_rd(struct root_domain *rd);
extern void sched_put_rd(struct root_domain *rd);
#ifdef HAVE_RT_PUSH_IPI
extern void rto_push_irq_work_func(struct irq_work *work);
#endif
#endif /* CONFIG_SMP */
#ifdef CONFIG_UCLAMP_TASK
/*
* struct uclamp_bucket - Utilization clamp bucket
* @value: utilization clamp value for tasks on this clamp bucket
* @tasks: number of RUNNABLE tasks on this clamp bucket
*
* Keep track of how many tasks are RUNNABLE for a given utilization
* clamp value.
*/
struct uclamp_bucket {
unsigned long value : bits_per(SCHED_CAPACITY_SCALE);
unsigned long tasks : BITS_PER_LONG - bits_per(SCHED_CAPACITY_SCALE);
};
/*
* struct uclamp_rq - rq's utilization clamp
* @value: currently active clamp values for a rq
* @bucket: utilization clamp buckets affecting a rq
*
* Keep track of RUNNABLE tasks on a rq to aggregate their clamp values.
* A clamp value is affecting a rq when there is at least one task RUNNABLE
* (or actually running) with that value.
*
* There are up to UCLAMP_CNT possible different clamp values, currently there
* are only two: minimum utilization and maximum utilization.
*
* All utilization clamping values are MAX aggregated, since:
* - for util_min: we want to run the CPU at least at the max of the minimum
* utilization required by its currently RUNNABLE tasks.
* - for util_max: we want to allow the CPU to run up to the max of the
* maximum utilization allowed by its currently RUNNABLE tasks.
*
* Since on each system we expect only a limited number of different
* utilization clamp values (UCLAMP_BUCKETS), use a simple array to track
* the metrics required to compute all the per-rq utilization clamp values.
*/
struct uclamp_rq {
unsigned int value;
struct uclamp_bucket bucket[UCLAMP_BUCKETS];
};
DECLARE_STATIC_KEY_FALSE(sched_uclamp_used);
#endif /* CONFIG_UCLAMP_TASK */
/*
* This is the main, per-CPU runqueue data structure.
*
* Locking rule: those places that want to lock multiple runqueues
* (such as the load balancing or the thread migration code), lock
* acquire operations must be ordered by ascending &runqueue.
*/
struct rq {
/* runqueue lock: */
raw_spinlock_t __lock;
/*
* nr_running and cpu_load should be in the same cacheline because
* remote CPUs use both these fields when doing load calculation.
*/
unsigned int nr_running;
#ifdef CONFIG_NUMA_BALANCING
unsigned int nr_numa_running;
unsigned int nr_preferred_running;
unsigned int numa_migrate_on;
#endif
#ifdef CONFIG_NO_HZ_COMMON
#ifdef CONFIG_SMP
unsigned long last_blocked_load_update_tick;
unsigned int has_blocked_load;
call_single_data_t nohz_csd;
#endif /* CONFIG_SMP */
unsigned int nohz_tick_stopped;
atomic_t nohz_flags;
#endif /* CONFIG_NO_HZ_COMMON */
#ifdef CONFIG_SMP
unsigned int ttwu_pending;
#endif
u64 nr_switches;
#ifdef CONFIG_UCLAMP_TASK
/* Utilization clamp values based on CPU's RUNNABLE tasks */
struct uclamp_rq uclamp[UCLAMP_CNT] ____cacheline_aligned;
unsigned int uclamp_flags;
#define UCLAMP_FLAG_IDLE 0x01
#endif
struct cfs_rq cfs;
struct rt_rq rt;
struct dl_rq dl;
#ifdef CONFIG_FAIR_GROUP_SCHED
/* list of leaf cfs_rq on this CPU: */
struct list_head leaf_cfs_rq_list;
struct list_head *tmp_alone_branch;
#endif /* CONFIG_FAIR_GROUP_SCHED */
/*
* This is part of a global counter where only the total sum
* over all CPUs matters. A task can increase this counter on
* one CPU and if it got migrated afterwards it may decrease
* it on another CPU. Always updated under the runqueue lock:
*/
unsigned int nr_uninterruptible;
struct task_struct __rcu *curr;
struct task_struct *idle;
struct task_struct *stop;
unsigned long next_balance;
struct mm_struct *prev_mm;
unsigned int clock_update_flags;
u64 clock;
/* Ensure that all clocks are in the same cache line */
u64 clock_task ____cacheline_aligned;
u64 clock_pelt;
unsigned long lost_idle_time;
atomic_t nr_iowait;
#ifdef CONFIG_SCHED_DEBUG
u64 last_seen_need_resched_ns;
int ticks_without_resched;
#endif
#ifdef CONFIG_MEMBARRIER
int membarrier_state;
#endif
#ifdef CONFIG_SMP
struct root_domain *rd;
struct sched_domain __rcu *sd;
unsigned long cpu_capacity;
unsigned long cpu_capacity_orig;
struct callback_head *balance_callback;
unsigned char nohz_idle_balance;
unsigned char idle_balance;
unsigned long misfit_task_load;
/* For active balancing */
int active_balance;
int push_cpu;
struct cpu_stop_work active_balance_work;
/* CPU of this runqueue: */
int cpu;
int online;
struct list_head cfs_tasks;
struct sched_avg avg_rt;
struct sched_avg avg_dl;
#ifdef CONFIG_HAVE_SCHED_AVG_IRQ
struct sched_avg avg_irq;
#endif
#ifdef CONFIG_SCHED_THERMAL_PRESSURE
struct sched_avg avg_thermal;
#endif
u64 idle_stamp;
u64 avg_idle;
unsigned long wake_stamp;
u64 wake_avg_idle;
/* This is used to determine avg_idle's max value */
u64 max_idle_balance_cost;
#ifdef CONFIG_HOTPLUG_CPU
struct rcuwait hotplug_wait;
#endif
#endif /* CONFIG_SMP */
#ifdef CONFIG_IRQ_TIME_ACCOUNTING
u64 prev_irq_time;
#endif
#ifdef CONFIG_PARAVIRT
u64 prev_steal_time;
#endif
#ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING
u64 prev_steal_time_rq;
#endif
/* calc_load related fields */
unsigned long calc_load_update;
long calc_load_active;
#ifdef CONFIG_SCHED_HRTICK
#ifdef CONFIG_SMP
call_single_data_t hrtick_csd;
#endif
struct hrtimer hrtick_timer;
ktime_t hrtick_time;
#endif
#ifdef CONFIG_SCHEDSTATS
/* 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;
/* schedule() stats */
unsigned int sched_count;
unsigned int sched_goidle;
/* try_to_wake_up() stats */
unsigned int ttwu_count;
unsigned int ttwu_local;
#endif
#ifdef CONFIG_CPU_IDLE
/* Must be inspected within a rcu lock section */
struct cpuidle_state *idle_state;
#endif
#ifdef CONFIG_SMP
unsigned int nr_pinned;
#endif
unsigned int push_busy;
struct cpu_stop_work push_work;
#ifdef CONFIG_SCHED_CORE
/* per rq */
struct rq *core;
struct task_struct *core_pick;
unsigned int core_enabled;
unsigned int core_sched_seq;
struct rb_root core_tree;
/* shared state -- careful with sched_core_cpu_deactivate() */
unsigned int core_task_seq;
unsigned int core_pick_seq;
unsigned long core_cookie;
unsigned char core_forceidle;
unsigned int core_forceidle_seq;
#endif
};
#ifdef CONFIG_FAIR_GROUP_SCHED
/* CPU runqueue to which this cfs_rq is attached */
static inline struct rq *rq_of(struct cfs_rq *cfs_rq)
{
return cfs_rq->rq;
}
#else
static inline struct rq *rq_of(struct cfs_rq *cfs_rq)
{
return container_of(cfs_rq, struct rq, cfs);
}
#endif
static inline int cpu_of(struct rq *rq)
{
#ifdef CONFIG_SMP
return rq->cpu;
#else
return 0;
#endif
}
#define MDF_PUSH 0x01
static inline bool is_migration_disabled(struct task_struct *p)
{
#ifdef CONFIG_SMP
return p->migration_disabled;
#else
return false;
#endif
}
struct sched_group;
#ifdef CONFIG_SCHED_CORE
static inline struct cpumask *sched_group_span(struct sched_group *sg);
DECLARE_STATIC_KEY_FALSE(__sched_core_enabled);
static inline bool sched_core_enabled(struct rq *rq)
{
return static_branch_unlikely(&__sched_core_enabled) && rq->core_enabled;
}
static inline bool sched_core_disabled(void)
{
return !static_branch_unlikely(&__sched_core_enabled);
}
/*
* Be careful with this function; not for general use. The return value isn't
* stable unless you actually hold a relevant rq->__lock.
*/
static inline raw_spinlock_t *rq_lockp(struct rq *rq)
{
if (sched_core_enabled(rq))
return &rq->core->__lock;
return &rq->__lock;
}
static inline raw_spinlock_t *__rq_lockp(struct rq *rq)
{
if (rq->core_enabled)
return &rq->core->__lock;
return &rq->__lock;
}
bool cfs_prio_less(struct task_struct *a, struct task_struct *b, bool fi);
/*
* Helpers to check if the CPU's core cookie matches with the task's cookie
* when core scheduling is enabled.
* A special case is that the task's cookie always matches with CPU's core
* cookie if the CPU is in an idle core.
*/
static inline bool sched_cpu_cookie_match(struct rq *rq, struct task_struct *p)
{
/* Ignore cookie match if core scheduler is not enabled on the CPU. */
if (!sched_core_enabled(rq))
return true;
return rq->core->core_cookie == p->core_cookie;
}
static inline bool sched_core_cookie_match(struct rq *rq, struct task_struct *p)
{
bool idle_core = true;
int cpu;
/* Ignore cookie match if core scheduler is not enabled on the CPU. */
if (!sched_core_enabled(rq))
return true;
for_each_cpu(cpu, cpu_smt_mask(cpu_of(rq))) {
if (!available_idle_cpu(cpu)) {
idle_core = false;
break;
}
}
/*
* A CPU in an idle core is always the best choice for tasks with
* cookies.
*/
return idle_core || rq->core->core_cookie == p->core_cookie;
}
static inline bool sched_group_cookie_match(struct rq *rq,
struct task_struct *p,
struct sched_group *group)
{
int cpu;
/* Ignore cookie match if core scheduler is not enabled on the CPU. */
if (!sched_core_enabled(rq))
return true;
for_each_cpu_and(cpu, sched_group_span(group), p->cpus_ptr) {
if (sched_core_cookie_match(rq, p))
return true;
}
return false;
}
extern void queue_core_balance(struct rq *rq);
static inline bool sched_core_enqueued(struct task_struct *p)
{
return !RB_EMPTY_NODE(&p->core_node);
}
extern void sched_core_enqueue(struct rq *rq, struct task_struct *p);
extern void sched_core_dequeue(struct rq *rq, struct task_struct *p);
extern void sched_core_get(void);
extern void sched_core_put(void);
#else /* !CONFIG_SCHED_CORE */
static inline bool sched_core_enabled(struct rq *rq)
{
return false;
}
static inline bool sched_core_disabled(void)
{
return true;
}
static inline raw_spinlock_t *rq_lockp(struct rq *rq)
{
return &rq->__lock;
}
static inline raw_spinlock_t *__rq_lockp(struct rq *rq)
{
return &rq->__lock;
}
static inline void queue_core_balance(struct rq *rq)
{
}
static inline bool sched_cpu_cookie_match(struct rq *rq, struct task_struct *p)
{
return true;
}
static inline bool sched_core_cookie_match(struct rq *rq, struct task_struct *p)
{
return true;
}
static inline bool sched_group_cookie_match(struct rq *rq,
struct task_struct *p,
struct sched_group *group)
{
return true;
}
#endif /* CONFIG_SCHED_CORE */
static inline void lockdep_assert_rq_held(struct rq *rq)
{
lockdep_assert_held(__rq_lockp(rq));
}
extern void raw_spin_rq_lock_nested(struct rq *rq, int subclass);
extern bool raw_spin_rq_trylock(struct rq *rq);
extern void raw_spin_rq_unlock(struct rq *rq);
static inline void raw_spin_rq_lock(struct rq *rq)
{
raw_spin_rq_lock_nested(rq, 0);
}
static inline void raw_spin_rq_lock_irq(struct rq *rq)
{
local_irq_disable();
raw_spin_rq_lock(rq);
}
static inline void raw_spin_rq_unlock_irq(struct rq *rq)
{
raw_spin_rq_unlock(rq);
local_irq_enable();
}
static inline unsigned long _raw_spin_rq_lock_irqsave(struct rq *rq)
{
unsigned long flags;
local_irq_save(flags);
raw_spin_rq_lock(rq);
return flags;
}
static inline void raw_spin_rq_unlock_irqrestore(struct rq *rq, unsigned long flags)
{
raw_spin_rq_unlock(rq);
local_irq_restore(flags);
}
#define raw_spin_rq_lock_irqsave(rq, flags) \
do { \
flags = _raw_spin_rq_lock_irqsave(rq); \
} while (0)
#ifdef CONFIG_SCHED_SMT
extern void __update_idle_core(struct rq *rq);
static inline void update_idle_core(struct rq *rq)
{
if (static_branch_unlikely(&sched_smt_present))
__update_idle_core(rq);
}
#else
static inline void update_idle_core(struct rq *rq) { }
#endif
DECLARE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues);
#define cpu_rq(cpu) (&per_cpu(runqueues, (cpu)))
#define this_rq() this_cpu_ptr(&runqueues)
#define task_rq(p) cpu_rq(task_cpu(p))
#define cpu_curr(cpu) (cpu_rq(cpu)->curr)
#define raw_rq() raw_cpu_ptr(&runqueues)
#ifdef CONFIG_FAIR_GROUP_SCHED
static inline struct task_struct *task_of(struct sched_entity *se)
{
SCHED_WARN_ON(!entity_is_task(se));
return container_of(se, struct task_struct, se);
}
static inline struct cfs_rq *task_cfs_rq(struct task_struct *p)
{
return p->se.cfs_rq;
}
/* runqueue on which this entity is (to be) queued */
static inline struct cfs_rq *cfs_rq_of(struct sched_entity *se)
{
return se->cfs_rq;
}
/* runqueue "owned" by this group */
static inline struct cfs_rq *group_cfs_rq(struct sched_entity *grp)
{
return grp->my_q;
}
#else
static inline struct task_struct *task_of(struct sched_entity *se)
{
return container_of(se, struct task_struct, se);
}
static inline struct cfs_rq *task_cfs_rq(struct task_struct *p)
{
return &task_rq(p)->cfs;
}
static inline struct cfs_rq *cfs_rq_of(struct sched_entity *se)
{
struct task_struct *p = task_of(se);
struct rq *rq = task_rq(p);
return &rq->cfs;
}
/* runqueue "owned" by this group */
static inline struct cfs_rq *group_cfs_rq(struct sched_entity *grp)
{
return NULL;
}
#endif
extern void update_rq_clock(struct rq *rq);
/*
* rq::clock_update_flags bits
*
* %RQCF_REQ_SKIP - will request skipping of clock update on the next
* call to __schedule(). This is an optimisation to avoid
* neighbouring rq clock updates.
*
* %RQCF_ACT_SKIP - is set from inside of __schedule() when skipping is
* in effect and calls to update_rq_clock() are being ignored.
*
* %RQCF_UPDATED - is a debug flag that indicates whether a call has been
* made to update_rq_clock() since the last time rq::lock was pinned.
*
* If inside of __schedule(), clock_update_flags will have been
* shifted left (a left shift is a cheap operation for the fast path
* to promote %RQCF_REQ_SKIP to %RQCF_ACT_SKIP), so you must use,
*
* if (rq-clock_update_flags >= RQCF_UPDATED)
*
* to check if %RQCF_UPDATED is set. It'll never be shifted more than
* one position though, because the next rq_unpin_lock() will shift it
* back.
*/
#define RQCF_REQ_SKIP 0x01
#define RQCF_ACT_SKIP 0x02
#define RQCF_UPDATED 0x04
static inline void assert_clock_updated(struct rq *rq)
{
/*
* The only reason for not seeing a clock update since the
* last rq_pin_lock() is if we're currently skipping updates.
*/
SCHED_WARN_ON(rq->clock_update_flags < RQCF_ACT_SKIP);
}
static inline u64 rq_clock(struct rq *rq)
{
lockdep_assert_rq_held(rq);
assert_clock_updated(rq);
return rq->clock;
}
static inline u64 rq_clock_task(struct rq *rq)
{
lockdep_assert_rq_held(rq);
assert_clock_updated(rq);
return rq->clock_task;
}
/**
* By default the decay is the default pelt decay period.
* The decay shift can change the decay period in
* multiples of 32.
* Decay shift Decay period(ms)
* 0 32
* 1 64
* 2 128
* 3 256
* 4 512
*/
extern int sched_thermal_decay_shift;
static inline u64 rq_clock_thermal(struct rq *rq)
{
return rq_clock_task(rq) >> sched_thermal_decay_shift;
}
static inline void rq_clock_skip_update(struct rq *rq)
{
lockdep_assert_rq_held(rq);
rq->clock_update_flags |= RQCF_REQ_SKIP;
}
/*
* See rt task throttling, which is the only time a skip
* request is canceled.
*/
static inline void rq_clock_cancel_skipupdate(struct rq *rq)
{
lockdep_assert_rq_held(rq);
rq->clock_update_flags &= ~RQCF_REQ_SKIP;
}
struct rq_flags {
unsigned long flags;
struct pin_cookie cookie;
#ifdef CONFIG_SCHED_DEBUG
/*
* A copy of (rq::clock_update_flags & RQCF_UPDATED) for the
* current pin context is stashed here in case it needs to be
* restored in rq_repin_lock().
*/
unsigned int clock_update_flags;
#endif
};
extern struct callback_head balance_push_callback;
/*
* Lockdep annotation that avoids accidental unlocks; it's like a
* sticky/continuous lockdep_assert_held().
*
* This avoids code that has access to 'struct rq *rq' (basically everything in
* the scheduler) from accidentally unlocking the rq if they do not also have a
* copy of the (on-stack) 'struct rq_flags rf'.
*
* Also see Documentation/locking/lockdep-design.rst.
*/
static inline void rq_pin_lock(struct rq *rq, struct rq_flags *rf)
{
rf->cookie = lockdep_pin_lock(__rq_lockp(rq));
#ifdef CONFIG_SCHED_DEBUG
rq->clock_update_flags &= (RQCF_REQ_SKIP|RQCF_ACT_SKIP);
rf->clock_update_flags = 0;
#ifdef CONFIG_SMP
SCHED_WARN_ON(rq->balance_callback && rq->balance_callback != &balance_push_callback);
#endif
#endif
}
static inline void rq_unpin_lock(struct rq *rq, struct rq_flags *rf)
{
#ifdef CONFIG_SCHED_DEBUG
if (rq->clock_update_flags > RQCF_ACT_SKIP)
rf->clock_update_flags = RQCF_UPDATED;
#endif
lockdep_unpin_lock(__rq_lockp(rq), rf->cookie);
}
static inline void rq_repin_lock(struct rq *rq, struct rq_flags *rf)
{
lockdep_repin_lock(__rq_lockp(rq), rf->cookie);
#ifdef CONFIG_SCHED_DEBUG
/*
* Restore the value we stashed in @rf for this pin context.
*/
rq->clock_update_flags |= rf->clock_update_flags;
#endif
}
struct rq *__task_rq_lock(struct task_struct *p, struct rq_flags *rf)
__acquires(rq->lock);
struct rq *task_rq_lock(struct task_struct *p, struct rq_flags *rf)
__acquires(p->pi_lock)
__acquires(rq->lock);
static inline void __task_rq_unlock(struct rq *rq, struct rq_flags *rf)
__releases(rq->lock)
{
rq_unpin_lock(rq, rf);
raw_spin_rq_unlock(rq);
}
static inline void
task_rq_unlock(struct rq *rq, struct task_struct *p, struct rq_flags *rf)
__releases(rq->lock)
__releases(p->pi_lock)
{
rq_unpin_lock(rq, rf);
raw_spin_rq_unlock(rq);
raw_spin_unlock_irqrestore(&p->pi_lock, rf->flags);
}
static inline void
rq_lock_irqsave(struct rq *rq, struct rq_flags *rf)
__acquires(rq->lock)
{
raw_spin_rq_lock_irqsave(rq, rf->flags);
rq_pin_lock(rq, rf);
}
static inline void
rq_lock_irq(struct rq *rq, struct rq_flags *rf)
__acquires(rq->lock)
{
raw_spin_rq_lock_irq(rq);
rq_pin_lock(rq, rf);
}
static inline void
rq_lock(struct rq *rq, struct rq_flags *rf)
__acquires(rq->lock)
{
raw_spin_rq_lock(rq);
rq_pin_lock(rq, rf);
}
static inline void
rq_unlock_irqrestore(struct rq *rq, struct rq_flags *rf)
__releases(rq->lock)
{
rq_unpin_lock(rq, rf);
raw_spin_rq_unlock_irqrestore(rq, rf->flags);
}
static inline void
rq_unlock_irq(struct rq *rq, struct rq_flags *rf)
__releases(rq->lock)
{
rq_unpin_lock(rq, rf);
raw_spin_rq_unlock_irq(rq);
}
static inline void
rq_unlock(struct rq *rq, struct rq_flags *rf)
__releases(rq->lock)
{
rq_unpin_lock(rq, rf);
raw_spin_rq_unlock(rq);
}
static inline struct rq *
this_rq_lock_irq(struct rq_flags *rf)
__acquires(rq->lock)
{
struct rq *rq;
local_irq_disable();
rq = this_rq();
rq_lock(rq, rf);
return rq;
}
#ifdef CONFIG_NUMA
enum numa_topology_type {
NUMA_DIRECT,
NUMA_GLUELESS_MESH,
NUMA_BACKPLANE,
};
extern enum numa_topology_type sched_numa_topology_type;
extern int sched_max_numa_distance;
extern bool find_numa_distance(int distance);
extern void sched_init_numa(void);
extern void sched_domains_numa_masks_set(unsigned int cpu);
extern void sched_domains_numa_masks_clear(unsigned int cpu);
extern int sched_numa_find_closest(const struct cpumask *cpus, int cpu);
#else
static inline void sched_init_numa(void) { }
static inline void sched_domains_numa_masks_set(unsigned int cpu) { }
static inline void sched_domains_numa_masks_clear(unsigned int cpu) { }
static inline int sched_numa_find_closest(const struct cpumask *cpus, int cpu)
{
return nr_cpu_ids;
}
#endif
#ifdef CONFIG_NUMA_BALANCING
/* The regions in numa_faults array from task_struct */
enum numa_faults_stats {
NUMA_MEM = 0,
NUMA_CPU,
NUMA_MEMBUF,
NUMA_CPUBUF
};
extern void sched_setnuma(struct task_struct *p, int node);
extern int migrate_task_to(struct task_struct *p, int cpu);
extern int migrate_swap(struct task_struct *p, struct task_struct *t,
int cpu, int scpu);
extern void init_numa_balancing(unsigned long clone_flags, struct task_struct *p);
#else
static inline void
init_numa_balancing(unsigned long clone_flags, struct task_struct *p)
{
}
#endif /* CONFIG_NUMA_BALANCING */
#ifdef CONFIG_SMP
static inline void
queue_balance_callback(struct rq *rq,
struct callback_head *head,
void (*func)(struct rq *rq))
{
lockdep_assert_rq_held(rq);
if (unlikely(head->next || rq->balance_callback == &balance_push_callback))
return;
head->func = (void (*)(struct callback_head *))func;
head->next = rq->balance_callback;
rq->balance_callback = head;
}
#define rcu_dereference_check_sched_domain(p) \
rcu_dereference_check((p), \
lockdep_is_held(&sched_domains_mutex))
/*
* The domain tree (rq->sd) is protected by RCU's quiescent state transition.
* See destroy_sched_domains: call_rcu for details.
*
* The domain tree of any CPU may only be accessed from within
* preempt-disabled sections.
*/
#define for_each_domain(cpu, __sd) \
for (__sd = rcu_dereference_check_sched_domain(cpu_rq(cpu)->sd); \
__sd; __sd = __sd->parent)
/**
* highest_flag_domain - Return highest sched_domain containing flag.
* @cpu: The CPU whose highest level of sched domain is to
* be returned.
* @flag: The flag to check for the highest sched_domain
* for the given CPU.
*
* Returns the highest sched_domain of a CPU which contains the given flag.
*/
static inline struct sched_domain *highest_flag_domain(int cpu, int flag)
{
struct sched_domain *sd, *hsd = NULL;
for_each_domain(cpu, sd) {
if (!(sd->flags & flag))
break;
hsd = sd;
}
return hsd;
}
static inline struct sched_domain *lowest_flag_domain(int cpu, int flag)
{
struct sched_domain *sd;
for_each_domain(cpu, sd) {
if (sd->flags & flag)
break;
}
return sd;
}
DECLARE_PER_CPU(struct sched_domain __rcu *, sd_llc);
DECLARE_PER_CPU(int, sd_llc_size);
DECLARE_PER_CPU(int, sd_llc_id);
DECLARE_PER_CPU(struct sched_domain_shared __rcu *, sd_llc_shared);
DECLARE_PER_CPU(struct sched_domain __rcu *, sd_numa);
DECLARE_PER_CPU(struct sched_domain __rcu *, sd_asym_packing);
DECLARE_PER_CPU(struct sched_domain __rcu *, sd_asym_cpucapacity);
extern struct static_key_false sched_asym_cpucapacity;
struct sched_group_capacity {
atomic_t ref;
/*
* CPU capacity of this group, SCHED_CAPACITY_SCALE being max capacity
* for a single CPU.
*/
unsigned long capacity;
unsigned long min_capacity; /* Min per-CPU capacity in group */
unsigned long max_capacity; /* Max per-CPU capacity in group */
unsigned long next_update;
int imbalance; /* XXX unrelated to capacity but shared group state */
#ifdef CONFIG_SCHED_DEBUG
int id;
#endif
unsigned long cpumask[]; /* Balance mask */
};
struct sched_group {
struct sched_group *next; /* Must be a circular list */
atomic_t ref;
unsigned int group_weight;
struct sched_group_capacity *sgc;
int asym_prefer_cpu; /* CPU of highest priority in group */
int flags;
/*
* The CPUs this group covers.
*
* NOTE: this field is variable length. (Allocated dynamically
* by attaching extra space to the end of the structure,
* depending on how many CPUs the kernel has booted up with)
*/
unsigned long cpumask[];
};
static inline struct cpumask *sched_group_span(struct sched_group *sg)
{
return to_cpumask(sg->cpumask);
}
/*
* See build_balance_mask().
*/
static inline struct cpumask *group_balance_mask(struct sched_group *sg)
{
return to_cpumask(sg->sgc->cpumask);
}
/**
* group_first_cpu - Returns the first CPU in the cpumask of a sched_group.
* @group: The group whose first CPU is to be returned.
*/
static inline unsigned int group_first_cpu(struct sched_group *group)
{
return cpumask_first(sched_group_span(group));
}
extern int group_balance_cpu(struct sched_group *sg);
#ifdef CONFIG_SCHED_DEBUG
void update_sched_domain_debugfs(void);
void dirty_sched_domain_sysctl(int cpu);
#else
static inline void update_sched_domain_debugfs(void)
{
}
static inline void dirty_sched_domain_sysctl(int cpu)
{
}
#endif
extern int sched_update_scaling(void);
extern void flush_smp_call_function_from_idle(void);
#else /* !CONFIG_SMP: */
static inline void flush_smp_call_function_from_idle(void) { }
#endif
#include "stats.h"
#include "autogroup.h"
#ifdef CONFIG_CGROUP_SCHED
/*
* Return the group to which this tasks belongs.
*
* We cannot use task_css() and friends because the cgroup subsystem
* changes that value before the cgroup_subsys::attach() method is called,
* therefore we cannot pin it and might observe the wrong value.
*
* The same is true for autogroup's p->signal->autogroup->tg, the autogroup
* core changes this before calling sched_move_task().
*
* Instead we use a 'copy' which is updated from sched_move_task() while
* holding both task_struct::pi_lock and rq::lock.
*/
static inline struct task_group *task_group(struct task_struct *p)
{
return p->sched_task_group;
}
/* Change a task's cfs_rq and parent entity if it moves across CPUs/groups */
static inline void set_task_rq(struct task_struct *p, unsigned int cpu)
{
#if defined(CONFIG_FAIR_GROUP_SCHED) || defined(CONFIG_RT_GROUP_SCHED)
struct task_group *tg = task_group(p);
#endif
#ifdef CONFIG_FAIR_GROUP_SCHED
set_task_rq_fair(&p->se, p->se.cfs_rq, tg->cfs_rq[cpu]);
p->se.cfs_rq = tg->cfs_rq[cpu];
p->se.parent = tg->se[cpu];
#endif
#ifdef CONFIG_RT_GROUP_SCHED
p->rt.rt_rq = tg->rt_rq[cpu];
p->rt.parent = tg->rt_se[cpu];
#endif
}
#else /* CONFIG_CGROUP_SCHED */
static inline void set_task_rq(struct task_struct *p, unsigned int cpu) { }
static inline struct task_group *task_group(struct task_struct *p)
{
return NULL;
}
#endif /* CONFIG_CGROUP_SCHED */
static inline void __set_task_cpu(struct task_struct *p, unsigned int cpu)
{
set_task_rq(p, cpu);
#ifdef CONFIG_SMP
/*
* After ->cpu is set up to a new value, task_rq_lock(p, ...) can be
* successfully executed on another CPU. We must ensure that updates of
* per-task data have been completed by this moment.
*/
smp_wmb();
WRITE_ONCE(task_thread_info(p)->cpu, cpu);
p->wake_cpu = cpu;
#endif
}
/*
* Tunables that become constants when CONFIG_SCHED_DEBUG is off:
*/
#ifdef CONFIG_SCHED_DEBUG
# include <linux/static_key.h>
# define const_debug __read_mostly
#else
# define const_debug const
#endif
#define SCHED_FEAT(name, enabled) \
__SCHED_FEAT_##name ,
enum {
#include "features.h"
__SCHED_FEAT_NR,
};
#undef SCHED_FEAT
#ifdef CONFIG_SCHED_DEBUG
/*
* To support run-time toggling of sched features, all the translation units
* (but core.c) reference the sysctl_sched_features defined in core.c.
*/
extern const_debug unsigned int sysctl_sched_features;
#ifdef CONFIG_JUMP_LABEL
#define SCHED_FEAT(name, enabled) \
static __always_inline bool static_branch_##name(struct static_key *key) \
{ \
return static_key_##enabled(key); \
}
#include "features.h"
#undef SCHED_FEAT
extern struct static_key sched_feat_keys[__SCHED_FEAT_NR];
#define sched_feat(x) (static_branch_##x(&sched_feat_keys[__SCHED_FEAT_##x]))
#else /* !CONFIG_JUMP_LABEL */
#define sched_feat(x) (sysctl_sched_features & (1UL << __SCHED_FEAT_##x))
#endif /* CONFIG_JUMP_LABEL */
#else /* !SCHED_DEBUG */
/*
* Each translation unit has its own copy of sysctl_sched_features to allow
* constants propagation at compile time and compiler optimization based on
* features default.
*/
#define SCHED_FEAT(name, enabled) \
(1UL << __SCHED_FEAT_##name) * enabled |
static const_debug __maybe_unused unsigned int sysctl_sched_features =
#include "features.h"
0;
#undef SCHED_FEAT
#define sched_feat(x) !!(sysctl_sched_features & (1UL << __SCHED_FEAT_##x))
#endif /* SCHED_DEBUG */
extern struct static_key_false sched_numa_balancing;
extern struct static_key_false sched_schedstats;
static inline u64 global_rt_period(void)
{
return (u64)sysctl_sched_rt_period * NSEC_PER_USEC;
}
static inline u64 global_rt_runtime(void)
{
if (sysctl_sched_rt_runtime < 0)
return RUNTIME_INF;
return (u64)sysctl_sched_rt_runtime * NSEC_PER_USEC;
}
static inline int task_current(struct rq *rq, struct task_struct *p)
{
return rq->curr == p;
}
static inline int task_running(struct rq *rq, struct task_struct *p)
{
#ifdef CONFIG_SMP
return p->on_cpu;
#else
return task_current(rq, p);
#endif
}
static inline int task_on_rq_queued(struct task_struct *p)
{
return p->on_rq == TASK_ON_RQ_QUEUED;
}
static inline int task_on_rq_migrating(struct task_struct *p)
{
return READ_ONCE(p->on_rq) == TASK_ON_RQ_MIGRATING;
}
/* Wake flags. The first three directly map to some SD flag value */
#define WF_EXEC 0x02 /* Wakeup after exec; maps to SD_BALANCE_EXEC */
#define WF_FORK 0x04 /* Wakeup after fork; maps to SD_BALANCE_FORK */
#define WF_TTWU 0x08 /* Wakeup; maps to SD_BALANCE_WAKE */
#define WF_SYNC 0x10 /* Waker goes to sleep after wakeup */
#define WF_MIGRATED 0x20 /* Internal use, task got migrated */
#define WF_ON_CPU 0x40 /* Wakee is on_cpu */
#ifdef CONFIG_SMP
static_assert(WF_EXEC == SD_BALANCE_EXEC);
static_assert(WF_FORK == SD_BALANCE_FORK);
static_assert(WF_TTWU == SD_BALANCE_WAKE);
#endif
/*
* To aid in avoiding the subversion of "niceness" due to uneven distribution
* of tasks with abnormal "nice" values across CPUs the contribution that
* each task makes to its run queue's load is weighted according to its
* scheduling class and "nice" value. For SCHED_NORMAL tasks this is just a
* scaled version of the new time slice allocation that they receive on time
* slice expiry etc.
*/
#define WEIGHT_IDLEPRIO 3
#define WMULT_IDLEPRIO 1431655765
extern const int sched_prio_to_weight[40];
extern const u32 sched_prio_to_wmult[40];
/*
* {de,en}queue flags:
*
* DEQUEUE_SLEEP - task is no longer runnable
* ENQUEUE_WAKEUP - task just became runnable
*
* SAVE/RESTORE - an otherwise spurious dequeue/enqueue, done to ensure tasks
* are in a known state which allows modification. Such pairs
* should preserve as much state as possible.
*
* MOVE - paired with SAVE/RESTORE, explicitly does not preserve the location
* in the runqueue.
*
* ENQUEUE_HEAD - place at front of runqueue (tail if not specified)
* ENQUEUE_REPLENISH - CBS (replenish runtime and postpone deadline)
* ENQUEUE_MIGRATED - the task was migrated during wakeup
*
*/
#define DEQUEUE_SLEEP 0x01
#define DEQUEUE_SAVE 0x02 /* Matches ENQUEUE_RESTORE */
#define DEQUEUE_MOVE 0x04 /* Matches ENQUEUE_MOVE */
#define DEQUEUE_NOCLOCK 0x08 /* Matches ENQUEUE_NOCLOCK */
#define ENQUEUE_WAKEUP 0x01
#define ENQUEUE_RESTORE 0x02
#define ENQUEUE_MOVE 0x04
#define ENQUEUE_NOCLOCK 0x08
#define ENQUEUE_HEAD 0x10
#define ENQUEUE_REPLENISH 0x20
#ifdef CONFIG_SMP
#define ENQUEUE_MIGRATED 0x40
#else
#define ENQUEUE_MIGRATED 0x00
#endif
#define RETRY_TASK ((void *)-1UL)
struct sched_class {
#ifdef CONFIG_UCLAMP_TASK
int uclamp_enabled;
#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);
void (*yield_task) (struct rq *rq);
bool (*yield_to_task)(struct rq *rq, struct task_struct *p);
void (*check_preempt_curr)(struct rq *rq, struct task_struct *p, int flags);
struct task_struct *(*pick_next_task)(struct rq *rq);
void (*put_prev_task)(struct rq *rq, struct task_struct *p);
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);
void (*set_cpus_allowed)(struct task_struct *p,
const struct cpumask *newmask,
u32 flags);
void (*rq_online)(struct rq *rq);
void (*rq_offline)(struct rq *rq);
struct rq *(*find_lock_rq)(struct task_struct *p, struct rq *rq);
#endif
void (*task_tick)(struct rq *rq, struct task_struct *p, int queued);
void (*task_fork)(struct task_struct *p);
void (*task_dead)(struct task_struct *p);
/*
* The switched_from() call is allowed to drop rq->lock, therefore we
* cannot assume the switched_from/switched_to pair is serialized by
* rq->lock. They are however serialized by p->pi_lock.
*/
void (*switched_from)(struct rq *this_rq, struct task_struct *task);
void (*switched_to) (struct rq *this_rq, struct task_struct *task);
void (*prio_changed) (struct rq *this_rq, struct task_struct *task,
int oldprio);
unsigned int (*get_rr_interval)(struct rq *rq,
struct task_struct *task);
void (*update_curr)(struct rq *rq);
#define TASK_SET_GROUP 0
#define TASK_MOVE_GROUP 1
#ifdef CONFIG_FAIR_GROUP_SCHED
void (*task_change_group)(struct task_struct *p, int type);
#endif
};
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);
}
static inline void set_next_task(struct rq *rq, struct task_struct *next)
{
next->sched_class->set_next_task(rq, next, false);
}
/*
* Helper to define a sched_class instance; each one is placed in a separate
* section which is ordered by the linker script:
*
* include/asm-generic/vmlinux.lds.h
*
* Also enforce alignment on the instance, not the type, to guarantee layout.
*/
#define DEFINE_SCHED_CLASS(name) \
const struct sched_class name##_sched_class \
__aligned(__alignof__(struct sched_class)) \
__section("__" #name "_sched_class")
/* Defined in include/asm-generic/vmlinux.lds.h */
extern struct sched_class __begin_sched_classes[];
extern struct sched_class __end_sched_classes[];
#define sched_class_highest (__end_sched_classes - 1)
#define sched_class_lowest (__begin_sched_classes - 1)
#define for_class_range(class, _from, _to) \
for (class = (_from); class != (_to); class--)
#define for_each_class(class) \
for_class_range(class, sched_class_highest, sched_class_lowest)
extern const struct sched_class stop_sched_class;
extern const struct sched_class dl_sched_class;
extern const struct sched_class rt_sched_class;
extern const struct sched_class fair_sched_class;
extern const struct sched_class idle_sched_class;
static inline bool sched_stop_runnable(struct rq *rq)
{
return rq->stop && task_on_rq_queued(rq->stop);
}
static inline bool sched_dl_runnable(struct rq *rq)
{
return rq->dl.dl_nr_running > 0;
}
static inline bool sched_rt_runnable(struct rq *rq)
{
return rq->rt.rt_queued > 0;
}
static inline bool sched_fair_runnable(struct rq *rq)
{
return rq->cfs.nr_running > 0;
}
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);
#define SCA_CHECK 0x01
#define SCA_MIGRATE_DISABLE 0x02
#define SCA_MIGRATE_ENABLE 0x04
#define SCA_USER 0x08
#ifdef CONFIG_SMP
extern void update_group_capacity(struct sched_domain *sd, int cpu);
extern void trigger_load_balance(struct rq *rq);
extern void set_cpus_allowed_common(struct task_struct *p, const struct cpumask *new_mask, u32 flags);
static inline struct task_struct *get_push_task(struct rq *rq)
{
struct task_struct *p = rq->curr;
lockdep_assert_rq_held(rq);
if (rq->push_busy)
return NULL;
if (p->nr_cpus_allowed == 1)
return NULL;
if (p->migration_disabled)
return NULL;
rq->push_busy = true;
return get_task_struct(p);
}
extern int push_cpu_stop(void *arg);
#endif
#ifdef CONFIG_CPU_IDLE
static inline void idle_set_state(struct rq *rq,
struct cpuidle_state *idle_state)
{
rq->idle_state = idle_state;
}
static inline struct cpuidle_state *idle_get_state(struct rq *rq)
{
SCHED_WARN_ON(!rcu_read_lock_held());
return rq->idle_state;
}
#else
static inline void idle_set_state(struct rq *rq,
struct cpuidle_state *idle_state)
{
}
static inline struct cpuidle_state *idle_get_state(struct rq *rq)
{
return NULL;
}
#endif
extern void schedule_idle(void);
extern void sysrq_sched_debug_show(void);
extern void sched_init_granularity(void);
extern void update_max_interval(void);
extern void init_sched_dl_class(void);
extern void init_sched_rt_class(void);
extern void init_sched_fair_class(void);
extern void reweight_task(struct task_struct *p, int prio);
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 struct dl_bandwidth def_dl_bandwidth;
extern void init_dl_bandwidth(struct dl_bandwidth *dl_b, u64 period, u64 runtime);
extern void init_dl_task_timer(struct sched_dl_entity *dl_se);
extern void init_dl_inactive_task_timer(struct sched_dl_entity *dl_se);
#define BW_SHIFT 20
#define BW_UNIT (1 << BW_SHIFT)
#define RATIO_SHIFT 8
#define MAX_BW_BITS (64 - BW_SHIFT)
#define MAX_BW ((1ULL << MAX_BW_BITS) - 1)
unsigned long to_ratio(u64 period, u64 runtime);
extern void init_entity_runnable_average(struct sched_entity *se);
extern void post_init_entity_util_avg(struct task_struct *p);
#ifdef CONFIG_NO_HZ_FULL
extern bool sched_can_stop_tick(struct rq *rq);
extern int __init sched_tick_offload_init(void);
/*
* Tick may be needed by tasks in the runqueue depending on their policy and
* requirements. If tick is needed, lets send the target an IPI to kick it out of
* nohz mode if necessary.
*/
static inline void sched_update_tick_dependency(struct rq *rq)
{
int cpu = cpu_of(rq);
if (!tick_nohz_full_cpu(cpu))
return;
if (sched_can_stop_tick(rq))
tick_nohz_dep_clear_cpu(cpu, TICK_DEP_BIT_SCHED);
else
tick_nohz_dep_set_cpu(cpu, TICK_DEP_BIT_SCHED);
}
#else
static inline int sched_tick_offload_init(void) { return 0; }
static inline void sched_update_tick_dependency(struct rq *rq) { }
#endif
static inline void add_nr_running(struct rq *rq, unsigned count)
{
unsigned prev_nr = rq->nr_running;
rq->nr_running = prev_nr + count;
if (trace_sched_update_nr_running_tp_enabled()) {
call_trace_sched_update_nr_running(rq, count);
}
#ifdef CONFIG_SMP
if (prev_nr < 2 && rq->nr_running >= 2) {
if (!READ_ONCE(rq->rd->overload))
WRITE_ONCE(rq->rd->overload, 1);
}
#endif
sched_update_tick_dependency(rq);
}
static inline void sub_nr_running(struct rq *rq, unsigned count)
{
rq->nr_running -= count;
if (trace_sched_update_nr_running_tp_enabled()) {
call_trace_sched_update_nr_running(rq, -count);
}
/* Check if we still need preemption */
sched_update_tick_dependency(rq);
}
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);
extern void check_preempt_curr(struct rq *rq, struct task_struct *p, int flags);
extern const_debug unsigned int sysctl_sched_nr_migrate;
extern const_debug unsigned int sysctl_sched_migration_cost;
#ifdef CONFIG_SCHED_DEBUG
extern unsigned int sysctl_sched_latency;
extern unsigned int sysctl_sched_min_granularity;
extern unsigned int sysctl_sched_idle_min_granularity;
extern unsigned int sysctl_sched_wakeup_granularity;
extern int sysctl_resched_latency_warn_ms;
extern int sysctl_resched_latency_warn_once;
extern unsigned int sysctl_sched_tunable_scaling;
extern unsigned int sysctl_numa_balancing_scan_delay;
extern unsigned int sysctl_numa_balancing_scan_period_min;
extern unsigned int sysctl_numa_balancing_scan_period_max;
extern unsigned int sysctl_numa_balancing_scan_size;
#endif
#ifdef CONFIG_SCHED_HRTICK
/*
* Use hrtick when:
* - enabled by features
* - hrtimer is actually high res
*/
static inline int hrtick_enabled(struct rq *rq)
{
if (!cpu_active(cpu_of(rq)))
return 0;
return hrtimer_is_hres_active(&rq->hrtick_timer);
}
static inline int hrtick_enabled_fair(struct rq *rq)
{
if (!sched_feat(HRTICK))
return 0;
return hrtick_enabled(rq);
}
static inline int hrtick_enabled_dl(struct rq *rq)
{
if (!sched_feat(HRTICK_DL))
return 0;
return hrtick_enabled(rq);
}
void hrtick_start(struct rq *rq, u64 delay);
#else
static inline int hrtick_enabled_fair(struct rq *rq)
{
return 0;
}
static inline int hrtick_enabled_dl(struct rq *rq)
{
return 0;
}
static inline int hrtick_enabled(struct rq *rq)
{
return 0;
}
#endif /* CONFIG_SCHED_HRTICK */
#ifndef arch_scale_freq_tick
static __always_inline
void arch_scale_freq_tick(void)
{
}
#endif
#ifndef arch_scale_freq_capacity
/**
* arch_scale_freq_capacity - get the frequency scale factor of a given CPU.
* @cpu: the CPU in question.
*
* Return: the frequency scale factor normalized against SCHED_CAPACITY_SCALE, i.e.
*
* f_curr
* ------ * SCHED_CAPACITY_SCALE
* f_max
*/
static __always_inline
unsigned long arch_scale_freq_capacity(int cpu)
{
return SCHED_CAPACITY_SCALE;
}
#endif
#ifdef CONFIG_SMP
static inline bool rq_order_less(struct rq *rq1, struct rq *rq2)
{
#ifdef CONFIG_SCHED_CORE
/*
* In order to not have {0,2},{1,3} turn into into an AB-BA,
* order by core-id first and cpu-id second.
*
* Notably:
*
* double_rq_lock(0,3); will take core-0, core-1 lock
* double_rq_lock(1,2); will take core-1, core-0 lock
*
* when only cpu-id is considered.
*/
if (rq1->core->cpu < rq2->core->cpu)
return true;
if (rq1->core->cpu > rq2->core->cpu)
return false;
/*
* __sched_core_flip() relies on SMT having cpu-id lock order.
*/
#endif
return rq1->cpu < rq2->cpu;
}
extern void double_rq_lock(struct rq *rq1, struct rq *rq2);
#ifdef CONFIG_PREEMPTION
/*
* fair double_lock_balance: Safely acquires both rq->locks in a fair
* way at the expense of forcing extra atomic operations in all
* invocations. This assures that the double_lock is acquired using the
* same underlying policy as the spinlock_t on this architecture, which
* reduces latency compared to the unfair variant below. However, it
* also adds more overhead and therefore may reduce throughput.
*/
static inline int _double_lock_balance(struct rq *this_rq, struct rq *busiest)
__releases(this_rq->lock)
__acquires(busiest->lock)
__acquires(this_rq->lock)
{
raw_spin_rq_unlock(this_rq);
double_rq_lock(this_rq, busiest);
return 1;
}
#else
/*
* Unfair double_lock_balance: Optimizes throughput at the expense of
* latency by eliminating extra atomic operations when the locks are
* already in proper order on entry. This favors lower CPU-ids and will
* grant the double lock to lower CPUs over higher ids under contention,
* regardless of entry order into the function.
*/
static inline int _double_lock_balance(struct rq *this_rq, struct rq *busiest)
__releases(this_rq->lock)
__acquires(busiest->lock)
__acquires(this_rq->lock)
{
if (__rq_lockp(this_rq) == __rq_lockp(busiest))
return 0;
if (likely(raw_spin_rq_trylock(busiest)))
return 0;
if (rq_order_less(this_rq, busiest)) {
raw_spin_rq_lock_nested(busiest, SINGLE_DEPTH_NESTING);
return 0;
}
raw_spin_rq_unlock(this_rq);
double_rq_lock(this_rq, busiest);
return 1;
}
#endif /* CONFIG_PREEMPTION */
/*
* double_lock_balance - lock the busiest runqueue, this_rq is locked already.
*/
static inline int double_lock_balance(struct rq *this_rq, struct rq *busiest)
{
lockdep_assert_irqs_disabled();
return _double_lock_balance(this_rq, busiest);
}
static inline void double_unlock_balance(struct rq *this_rq, struct rq *busiest)
__releases(busiest->lock)
{
if (__rq_lockp(this_rq) != __rq_lockp(busiest))
raw_spin_rq_unlock(busiest);
lock_set_subclass(&__rq_lockp(this_rq)->dep_map, 0, _RET_IP_);
}
static inline void double_lock(spinlock_t *l1, spinlock_t *l2)
{
if (l1 > l2)
swap(l1, l2);
spin_lock(l1);
spin_lock_nested(l2, SINGLE_DEPTH_NESTING);
}
static inline void double_lock_irq(spinlock_t *l1, spinlock_t *l2)
{
if (l1 > l2)
swap(l1, l2);
spin_lock_irq(l1);
spin_lock_nested(l2, SINGLE_DEPTH_NESTING);
}
static inline void double_raw_lock(raw_spinlock_t *l1, raw_spinlock_t *l2)
{
if (l1 > l2)
swap(l1, l2);
raw_spin_lock(l1);
raw_spin_lock_nested(l2, SINGLE_DEPTH_NESTING);
}
/*
* double_rq_unlock - safely unlock two runqueues
*
* Note this does not restore interrupts like task_rq_unlock,
* you need to do so manually after calling.
*/
static inline void double_rq_unlock(struct rq *rq1, struct rq *rq2)
__releases(rq1->lock)
__releases(rq2->lock)
{
if (__rq_lockp(rq1) != __rq_lockp(rq2))
raw_spin_rq_unlock(rq2);
else
__release(rq2->lock);
raw_spin_rq_unlock(rq1);
}
extern void set_rq_online (struct rq *rq);
extern void set_rq_offline(struct rq *rq);
extern bool sched_smp_initialized;
#else /* CONFIG_SMP */
/*
* double_rq_lock - safely lock two runqueues
*
* Note this does not disable interrupts like task_rq_lock,
* you need to do so manually before calling.
*/
static inline void double_rq_lock(struct rq *rq1, struct rq *rq2)
__acquires(rq1->lock)
__acquires(rq2->lock)
{
BUG_ON(!irqs_disabled());
BUG_ON(rq1 != rq2);
raw_spin_rq_lock(rq1);
__acquire(rq2->lock); /* Fake it out ;) */
}
/*
* double_rq_unlock - safely unlock two runqueues
*
* Note this does not restore interrupts like task_rq_unlock,
* you need to do so manually after calling.
*/
static inline void double_rq_unlock(struct rq *rq1, struct rq *rq2)
__releases(rq1->lock)
__releases(rq2->lock)
{
BUG_ON(rq1 != rq2);
raw_spin_rq_unlock(rq1);
__release(rq2->lock);
}
#endif
extern struct sched_entity *__pick_first_entity(struct cfs_rq *cfs_rq);
extern struct sched_entity *__pick_last_entity(struct cfs_rq *cfs_rq);
#ifdef CONFIG_SCHED_DEBUG
extern bool sched_debug_verbose;
extern void print_cfs_stats(struct seq_file *m, int cpu);
extern void print_rt_stats(struct seq_file *m, int cpu);
extern void print_dl_stats(struct seq_file *m, int cpu);
extern void print_cfs_rq(struct seq_file *m, int cpu, struct cfs_rq *cfs_rq);
extern void print_rt_rq(struct seq_file *m, int cpu, struct rt_rq *rt_rq);
extern void print_dl_rq(struct seq_file *m, int cpu, struct dl_rq *dl_rq);
extern void resched_latency_warn(int cpu, u64 latency);
#ifdef CONFIG_NUMA_BALANCING
extern void
show_numa_stats(struct task_struct *p, struct seq_file *m);
extern void
print_numa_stats(struct seq_file *m, int node, unsigned long tsf,
unsigned long tpf, unsigned long gsf, unsigned long gpf);
#endif /* CONFIG_NUMA_BALANCING */
#else
static inline void resched_latency_warn(int cpu, u64 latency) {}
#endif /* CONFIG_SCHED_DEBUG */
extern void init_cfs_rq(struct cfs_rq *cfs_rq);
extern void init_rt_rq(struct rt_rq *rt_rq);
extern void init_dl_rq(struct dl_rq *dl_rq);
extern void cfs_bandwidth_usage_inc(void);
extern void cfs_bandwidth_usage_dec(void);
#ifdef CONFIG_NO_HZ_COMMON
#define NOHZ_BALANCE_KICK_BIT 0
#define NOHZ_STATS_KICK_BIT 1
#define NOHZ_NEWILB_KICK_BIT 2
#define NOHZ_NEXT_KICK_BIT 3
/* Run rebalance_domains() */
#define NOHZ_BALANCE_KICK BIT(NOHZ_BALANCE_KICK_BIT)
/* Update blocked load */
#define NOHZ_STATS_KICK BIT(NOHZ_STATS_KICK_BIT)
/* Update blocked load when entering idle */
#define NOHZ_NEWILB_KICK BIT(NOHZ_NEWILB_KICK_BIT)
/* Update nohz.next_balance */
#define NOHZ_NEXT_KICK BIT(NOHZ_NEXT_KICK_BIT)
#define NOHZ_KICK_MASK (NOHZ_BALANCE_KICK | NOHZ_STATS_KICK | NOHZ_NEXT_KICK)
#define nohz_flags(cpu) (&cpu_rq(cpu)->nohz_flags)
extern void nohz_balance_exit_idle(struct rq *rq);
#else
static inline void nohz_balance_exit_idle(struct rq *rq) { }
#endif
#if defined(CONFIG_SMP) && defined(CONFIG_NO_HZ_COMMON)
extern void nohz_run_idle_balance(int cpu);
#else
static inline void nohz_run_idle_balance(int cpu) { }
#endif
#ifdef CONFIG_SMP
static inline
void __dl_update(struct dl_bw *dl_b, s64 bw)
{
struct root_domain *rd = container_of(dl_b, struct root_domain, dl_bw);
int i;
RCU_LOCKDEP_WARN(!rcu_read_lock_sched_held(),
"sched RCU must be held");
for_each_cpu_and(i, rd->span, cpu_active_mask) {
struct rq *rq = cpu_rq(i);
rq->dl.extra_bw += bw;
}
}
#else
static inline
void __dl_update(struct dl_bw *dl_b, s64 bw)
{
struct dl_rq *dl = container_of(dl_b, struct dl_rq, dl_bw);
dl->extra_bw += bw;
}
#endif
#ifdef CONFIG_IRQ_TIME_ACCOUNTING
struct irqtime {
u64 total;
u64 tick_delta;
u64 irq_start_time;
struct u64_stats_sync sync;
};
DECLARE_PER_CPU(struct irqtime, cpu_irqtime);
/*
* Returns the irqtime minus the softirq time computed by ksoftirqd.
* Otherwise ksoftirqd's sum_exec_runtime is subtracted its own runtime
* and never move forward.
*/
static inline u64 irq_time_read(int cpu)
{
struct irqtime *irqtime = &per_cpu(cpu_irqtime, cpu);
unsigned int seq;
u64 total;
do {
seq = __u64_stats_fetch_begin(&irqtime->sync);
total = irqtime->total;
} while (__u64_stats_fetch_retry(&irqtime->sync, seq));
return total;
}
#endif /* CONFIG_IRQ_TIME_ACCOUNTING */
#ifdef CONFIG_CPU_FREQ
DECLARE_PER_CPU(struct update_util_data __rcu *, cpufreq_update_util_data);
/**
* cpufreq_update_util - Take a note about CPU utilization changes.
* @rq: Runqueue to carry out the update for.
* @flags: Update reason flags.
*
* This function is called by the scheduler on the CPU whose utilization is
* being updated.
*
* It can only be called from RCU-sched read-side critical sections.
*
* The way cpufreq is currently arranged requires it to evaluate the CPU
* performance state (frequency/voltage) on a regular basis to prevent it from
* being stuck in a completely inadequate performance level for too long.
* That is not guaranteed to happen if the updates are only triggered from CFS
* and DL, though, because they may not be coming in if only RT tasks are
* active all the time (or there are RT tasks only).
*
* As a workaround for that issue, this function is called periodically by the
* RT sched class to trigger extra cpufreq updates to prevent it from stalling,
* but that really is a band-aid. Going forward it should be replaced with
* solutions targeted more specifically at RT tasks.
*/
static inline void cpufreq_update_util(struct rq *rq, unsigned int flags)
{
struct update_util_data *data;
data = rcu_dereference_sched(*per_cpu_ptr(&cpufreq_update_util_data,
cpu_of(rq)));
if (data)
data->func(data, rq_clock(rq), flags);
}
#else
static inline void cpufreq_update_util(struct rq *rq, unsigned int flags) {}
#endif /* CONFIG_CPU_FREQ */
#ifdef CONFIG_UCLAMP_TASK
unsigned long uclamp_eff_value(struct task_struct *p, enum uclamp_id clamp_id);
/**
* uclamp_rq_util_with - clamp @util with @rq and @p effective uclamp values.
* @rq: The rq to clamp against. Must not be NULL.
* @util: The util value to clamp.
* @p: The task to clamp against. Can be NULL if you want to clamp
* against @rq only.
*
* Clamps the passed @util to the max(@rq, @p) effective uclamp values.
*
* If sched_uclamp_used static key is disabled, then just return the util
* without any clamping since uclamp aggregation at the rq level in the fast
* path is disabled, rendering this operation a NOP.
*
* Use uclamp_eff_value() if you don't care about uclamp values at rq level. It
* will return the correct effective uclamp value of the task even if the
* static key is disabled.
*/
static __always_inline
unsigned long uclamp_rq_util_with(struct rq *rq, unsigned long util,
struct task_struct *p)
{
unsigned long min_util = 0;
unsigned long max_util = 0;
if (!static_branch_likely(&sched_uclamp_used))
return util;
if (p) {
min_util = uclamp_eff_value(p, UCLAMP_MIN);
max_util = uclamp_eff_value(p, UCLAMP_MAX);
/*
* Ignore last runnable task's max clamp, as this task will
* reset it. Similarly, no need to read the rq's min clamp.
*/
if (rq->uclamp_flags & UCLAMP_FLAG_IDLE)
goto out;
}
min_util = max_t(unsigned long, min_util, READ_ONCE(rq->uclamp[UCLAMP_MIN].value));
max_util = max_t(unsigned long, max_util, READ_ONCE(rq->uclamp[UCLAMP_MAX].value));
out:
/*
* Since CPU's {min,max}_util clamps are MAX aggregated considering
* RUNNABLE tasks with _different_ clamps, we can end up with an
* inversion. Fix it now when the clamps are applied.
*/
if (unlikely(min_util >= max_util))
return min_util;
return clamp(util, min_util, max_util);
}
/*
* When uclamp is compiled in, the aggregation at rq level is 'turned off'
* by default in the fast path and only gets turned on once userspace performs
* an operation that requires it.
*
* Returns true if userspace opted-in to use uclamp and aggregation at rq level
* hence is active.
*/
static inline bool uclamp_is_used(void)
{
return static_branch_likely(&sched_uclamp_used);
}
#else /* CONFIG_UCLAMP_TASK */
static inline
unsigned long uclamp_rq_util_with(struct rq *rq, unsigned long util,
struct task_struct *p)
{
return util;
}
static inline bool uclamp_is_used(void)
{
return false;
}
#endif /* CONFIG_UCLAMP_TASK */
#ifdef arch_scale_freq_capacity
# ifndef arch_scale_freq_invariant
# define arch_scale_freq_invariant() true
# endif
#else
# define arch_scale_freq_invariant() false
#endif
#ifdef CONFIG_SMP
static inline unsigned long capacity_orig_of(int cpu)
{
return cpu_rq(cpu)->cpu_capacity_orig;
}
/**
* enum cpu_util_type - CPU utilization type
* @FREQUENCY_UTIL: Utilization used to select frequency
* @ENERGY_UTIL: Utilization used during energy calculation
*
* The utilization signals of all scheduling classes (CFS/RT/DL) and IRQ time
* need to be aggregated differently depending on the usage made of them. This
* enum is used within effective_cpu_util() to differentiate the types of
* utilization expected by the callers, and adjust the aggregation accordingly.
*/
enum cpu_util_type {
FREQUENCY_UTIL,
ENERGY_UTIL,
};
unsigned long effective_cpu_util(int cpu, unsigned long util_cfs,
unsigned long max, enum cpu_util_type type,
struct task_struct *p);
static inline unsigned long cpu_bw_dl(struct rq *rq)
{
return (rq->dl.running_bw * SCHED_CAPACITY_SCALE) >> BW_SHIFT;
}
static inline unsigned long cpu_util_dl(struct rq *rq)
{
return READ_ONCE(rq->avg_dl.util_avg);
}
static inline unsigned long cpu_util_cfs(struct rq *rq)
{
unsigned long util = READ_ONCE(rq->cfs.avg.util_avg);
if (sched_feat(UTIL_EST)) {
util = max_t(unsigned long, util,
READ_ONCE(rq->cfs.avg.util_est.enqueued));
}
return util;
}
static inline unsigned long cpu_util_rt(struct rq *rq)
{
return READ_ONCE(rq->avg_rt.util_avg);
}
#endif
#ifdef CONFIG_HAVE_SCHED_AVG_IRQ
static inline unsigned long cpu_util_irq(struct rq *rq)
{
return rq->avg_irq.util_avg;
}
static inline
unsigned long scale_irq_capacity(unsigned long util, unsigned long irq, unsigned long max)
{
util *= (max - irq);
util /= max;
return util;
}
#else
static inline unsigned long cpu_util_irq(struct rq *rq)
{
return 0;
}
static inline
unsigned long scale_irq_capacity(unsigned long util, unsigned long irq, unsigned long max)
{
return util;
}
#endif
#if defined(CONFIG_ENERGY_MODEL) && defined(CONFIG_CPU_FREQ_GOV_SCHEDUTIL)
#define perf_domain_span(pd) (to_cpumask(((pd)->em_pd->cpus)))
DECLARE_STATIC_KEY_FALSE(sched_energy_present);
static inline bool sched_energy_enabled(void)
{
return static_branch_unlikely(&sched_energy_present);
}
#else /* ! (CONFIG_ENERGY_MODEL && CONFIG_CPU_FREQ_GOV_SCHEDUTIL) */
#define perf_domain_span(pd) NULL
static inline bool sched_energy_enabled(void) { return false; }
#endif /* CONFIG_ENERGY_MODEL && CONFIG_CPU_FREQ_GOV_SCHEDUTIL */
#ifdef CONFIG_MEMBARRIER
/*
* The scheduler provides memory barriers required by membarrier between:
* - prior user-space memory accesses and store to rq->membarrier_state,
* - store to rq->membarrier_state and following user-space memory accesses.
* In the same way it provides those guarantees around store to rq->curr.
*/
static inline void membarrier_switch_mm(struct rq *rq,
struct mm_struct *prev_mm,
struct mm_struct *next_mm)
{
int membarrier_state;
if (prev_mm == next_mm)
return;
membarrier_state = atomic_read(&next_mm->membarrier_state);
if (READ_ONCE(rq->membarrier_state) == membarrier_state)
return;
WRITE_ONCE(rq->membarrier_state, membarrier_state);
}
#else
static inline void membarrier_switch_mm(struct rq *rq,
struct mm_struct *prev_mm,
struct mm_struct *next_mm)
{
}
#endif
#ifdef CONFIG_SMP
static inline bool is_per_cpu_kthread(struct task_struct *p)
{
if (!(p->flags & PF_KTHREAD))
return false;
if (p->nr_cpus_allowed != 1)
return false;
return true;
}
#endif
extern void swake_up_all_locked(struct swait_queue_head *q);
extern void __prepare_to_swait(struct swait_queue_head *q, struct swait_queue *wait);
#ifdef CONFIG_PREEMPT_DYNAMIC
extern int preempt_dynamic_mode;
extern int sched_dynamic_mode(const char *str);
extern void sched_dynamic_update(int mode);
#endif
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