/* SPDX-License-Identifier: GPL-2.0 */

#ifdef CONFIG_SCHEDSTATS

/*
 * Expects runqueue lock to be held for atomicity of update
 */
static inline void
rq_sched_info_arrive(struct rq *rq, unsigned long long delta)
{
        if (rq) {
                rq->rq_sched_info.run_delay += delta;
                rq->rq_sched_info.pcount++;
        }
}

/*
 * Expects runqueue lock to be held for atomicity of update
 */
static inline void
rq_sched_info_depart(struct rq *rq, unsigned long long delta)
{
        if (rq)
                rq->rq_cpu_time += delta;
}

static inline void
rq_sched_info_dequeued(struct rq *rq, unsigned long long delta)
{
        if (rq)
                rq->rq_sched_info.run_delay += delta;
}
#define   schedstat_enabled()           static_branch_unlikely(&sched_schedstats)
#define __schedstat_inc(var)            do { var++; } while (0)
#define   schedstat_inc(var)            do { if (schedstat_enabled()) { var++; } } while (0)
#define __schedstat_add(var, amt)       do { var += (amt); } while (0)
#define   schedstat_add(var, amt)       do { if (schedstat_enabled()) { var += (amt); } } while (0)
#define __schedstat_set(var, val)       do { var = (val); } while (0)
#define   schedstat_set(var, val)       do { if (schedstat_enabled()) { var = (val); } } while (0)
#define   schedstat_val(var)            (var)
#define   schedstat_val_or_zero(var)    ((schedstat_enabled()) ? (var) : 0)

#else /* !CONFIG_SCHEDSTATS: */
static inline void rq_sched_info_arrive  (struct rq *rq, unsigned long long delta) { }
static inline void rq_sched_info_dequeued(struct rq *rq, unsigned long long delta) { }
static inline void rq_sched_info_depart  (struct rq *rq, unsigned long long delta) { }
# define   schedstat_enabled()          0
# define __schedstat_inc(var)           do { } while (0)
# define   schedstat_inc(var)           do { } while (0)
# define __schedstat_add(var, amt)      do { } while (0)
# define   schedstat_add(var, amt)      do { } while (0)
# define __schedstat_set(var, val)      do { } while (0)
# define   schedstat_set(var, val)      do { } while (0)
# define   schedstat_val(var)           0
# define   schedstat_val_or_zero(var)   0
#endif /* CONFIG_SCHEDSTATS */

#ifdef CONFIG_PSI
/*
 * PSI tracks state that persists across sleeps, such as iowaits and
 * memory stalls. As a result, it has to distinguish between sleeps,
 * where a task's runnable state changes, and requeues, where a task
 * and its state are being moved between CPUs and runqueues.
 */
static inline void psi_enqueue(struct task_struct *p, bool wakeup)
{
        int clear = 0, set = TSK_RUNNING;

        if (static_branch_likely(&psi_disabled))
                return;

        if (!wakeup || p->sched_psi_wake_requeue) {
                if (p->in_memstall)
                        set |= TSK_MEMSTALL;
                if (p->sched_psi_wake_requeue)
                        p->sched_psi_wake_requeue = 0;
        } else {
                if (p->in_iowait)
                        clear |= TSK_IOWAIT;
        }

        psi_task_change(p, clear, set);
}

static inline void psi_dequeue(struct task_struct *p, bool sleep)
{
        int clear = TSK_RUNNING;

        if (static_branch_likely(&psi_disabled))
                return;

        /*
         * A voluntary sleep is a dequeue followed by a task switch. To
         * avoid walking all ancestors twice, psi_task_switch() handles
         * TSK_RUNNING and TSK_IOWAIT for us when it moves TSK_ONCPU.
         * Do nothing here.
         */
        if (sleep)
                return;

        if (p->in_memstall)
                clear |= TSK_MEMSTALL;

        psi_task_change(p, clear, 0);
}

static inline void psi_ttwu_dequeue(struct task_struct *p)
{
        if (static_branch_likely(&psi_disabled))
                return;
        /*
         * Is the task being migrated during a wakeup? Make sure to
         * deregister its sleep-persistent psi states from the old
         * queue, and let psi_enqueue() know it has to requeue.
         */
        if (unlikely(p->in_iowait || p->in_memstall)) {
                struct rq_flags rf;
                struct rq *rq;
                int clear = 0;

                if (p->in_iowait)
                        clear |= TSK_IOWAIT;
                if (p->in_memstall)
                        clear |= TSK_MEMSTALL;

                rq = __task_rq_lock(p, &rf);
                psi_task_change(p, clear, 0);
                p->sched_psi_wake_requeue = 1;
                __task_rq_unlock(rq, &rf);
        }
}

static inline void psi_sched_switch(struct task_struct *prev,
                                    struct task_struct *next,
                                    bool sleep)
{
        if (static_branch_likely(&psi_disabled))
                return;

        psi_task_switch(prev, next, sleep);
}

#else /* CONFIG_PSI */
static inline void psi_enqueue(struct task_struct *p, bool wakeup) {}
static inline void psi_dequeue(struct task_struct *p, bool sleep) {}
static inline void psi_ttwu_dequeue(struct task_struct *p) {}
static inline void psi_sched_switch(struct task_struct *prev,
                                    struct task_struct *next,
                                    bool sleep) {}
#endif /* CONFIG_PSI */

#ifdef CONFIG_SCHED_INFO
static inline void sched_info_reset_dequeued(struct task_struct *t)
{
        t->sched_info.last_queued = 0;
}

/*
 * We are interested in knowing how long it was from the *first* time a
 * task was queued to the time that it finally hit a CPU, we call this routine
 * from dequeue_task() to account for possible rq->clock skew across CPUs. The
 * delta taken on each CPU would annul the skew.
 */
static inline void sched_info_dequeued(struct rq *rq, struct task_struct *t)
{
        unsigned long long now = rq_clock(rq), delta = 0;

        if (sched_info_on()) {
                if (t->sched_info.last_queued)
                        delta = now - t->sched_info.last_queued;
        }
        sched_info_reset_dequeued(t);
        t->sched_info.run_delay += delta;

        rq_sched_info_dequeued(rq, delta);
}

/*
 * Called when a task finally hits the CPU.  We can now calculate how
 * long it was waiting to run.  We also note when it began so that we
 * can keep stats on how long its timeslice is.
 */
static void sched_info_arrive(struct rq *rq, struct task_struct *t)
{
        unsigned long long now = rq_clock(rq), delta = 0;

        if (t->sched_info.last_queued)
                delta = now - t->sched_info.last_queued;
        sched_info_reset_dequeued(t);
        t->sched_info.run_delay += delta;
        t->sched_info.last_arrival = now;
        t->sched_info.pcount++;

        rq_sched_info_arrive(rq, delta);
}

/*
 * This function is only called from enqueue_task(), but also only updates
 * the timestamp if it is already not set.  It's assumed that
 * sched_info_dequeued() will clear that stamp when appropriate.
 */
static inline void sched_info_queued(struct rq *rq, struct task_struct *t)
{
        if (sched_info_on()) {
                if (!t->sched_info.last_queued)
                        t->sched_info.last_queued = rq_clock(rq);
        }
}

/*
 * Called when a process ceases being the active-running process involuntarily
 * due, typically, to expiring its time slice (this may also be called when
 * switching to the idle task).  Now we can calculate how long we ran.
 * Also, if the process is still in the TASK_RUNNING state, call
 * sched_info_queued() to mark that it has now again started waiting on
 * the runqueue.
 */
static inline void sched_info_depart(struct rq *rq, struct task_struct *t)
{
        unsigned long long delta = rq_clock(rq) - t->sched_info.last_arrival;

        rq_sched_info_depart(rq, delta);

        if (t->state == TASK_RUNNING)
                sched_info_queued(rq, t);
}

/*
 * Called when tasks are switched involuntarily due, typically, to expiring
 * their time slice.  (This may also be called when switching to or from
 * the idle task.)  We are only called when prev != next.
 */
static inline void
__sched_info_switch(struct rq *rq, struct task_struct *prev, struct task_struct *next)
{
        /*
         * prev now departs the CPU.  It's not interesting to record
         * stats about how efficient we were at scheduling the idle
         * process, however.
         */
        if (prev != rq->idle)
                sched_info_depart(rq, prev);

        if (next != rq->idle)
                sched_info_arrive(rq, next);
}

static inline void
sched_info_switch(struct rq *rq, struct task_struct *prev, struct task_struct *next)
{
        if (sched_info_on())
                __sched_info_switch(rq, prev, next);
}

#else /* !CONFIG_SCHED_INFO: */
# define sched_info_queued(rq, t)       do { } while (0)
# define sched_info_reset_dequeued(t)   do { } while (0)
# define sched_info_dequeued(rq, t)     do { } while (0)
# define sched_info_depart(rq, t)       do { } while (0)
# define sched_info_arrive(rq, next)    do { } while (0)
# define sched_info_switch(rq, t, next) do { } while (0)
#endif /* CONFIG_SCHED_INFO */