1 /* SPDX-License-Identifier: GPL-2.0 */
2
3 #ifdef CONFIG_SCHEDSTATS
4
5 /*
6 * Expects runqueue lock to be held for atomicity of update
7 */
8 static inline void
rq_sched_info_arrive(struct rq * rq,unsigned long long delta)9 rq_sched_info_arrive(struct rq *rq, unsigned long long delta)
10 {
11 if (rq) {
12 rq->rq_sched_info.run_delay += delta;
13 rq->rq_sched_info.pcount++;
14 }
15 }
16
17 /*
18 * Expects runqueue lock to be held for atomicity of update
19 */
20 static inline void
rq_sched_info_depart(struct rq * rq,unsigned long long delta)21 rq_sched_info_depart(struct rq *rq, unsigned long long delta)
22 {
23 if (rq)
24 rq->rq_cpu_time += delta;
25 }
26
27 static inline void
rq_sched_info_dequeue(struct rq * rq,unsigned long long delta)28 rq_sched_info_dequeue(struct rq *rq, unsigned long long delta)
29 {
30 if (rq)
31 rq->rq_sched_info.run_delay += delta;
32 }
33 #define schedstat_enabled() static_branch_unlikely(&sched_schedstats)
34 #define __schedstat_inc(var) do { var++; } while (0)
35 #define schedstat_inc(var) do { if (schedstat_enabled()) { var++; } } while (0)
36 #define __schedstat_add(var, amt) do { var += (amt); } while (0)
37 #define schedstat_add(var, amt) do { if (schedstat_enabled()) { var += (amt); } } while (0)
38 #define __schedstat_set(var, val) do { var = (val); } while (0)
39 #define schedstat_set(var, val) do { if (schedstat_enabled()) { var = (val); } } while (0)
40 #define schedstat_val(var) (var)
41 #define schedstat_val_or_zero(var) ((schedstat_enabled()) ? (var) : 0)
42
43 #else /* !CONFIG_SCHEDSTATS: */
rq_sched_info_arrive(struct rq * rq,unsigned long long delta)44 static inline void rq_sched_info_arrive (struct rq *rq, unsigned long long delta) { }
rq_sched_info_dequeue(struct rq * rq,unsigned long long delta)45 static inline void rq_sched_info_dequeue(struct rq *rq, unsigned long long delta) { }
rq_sched_info_depart(struct rq * rq,unsigned long long delta)46 static inline void rq_sched_info_depart (struct rq *rq, unsigned long long delta) { }
47 # define schedstat_enabled() 0
48 # define __schedstat_inc(var) do { } while (0)
49 # define schedstat_inc(var) do { } while (0)
50 # define __schedstat_add(var, amt) do { } while (0)
51 # define schedstat_add(var, amt) do { } while (0)
52 # define __schedstat_set(var, val) do { } while (0)
53 # define schedstat_set(var, val) do { } while (0)
54 # define schedstat_val(var) 0
55 # define schedstat_val_or_zero(var) 0
56 #endif /* CONFIG_SCHEDSTATS */
57
58 #ifdef CONFIG_PSI
59 /*
60 * PSI tracks state that persists across sleeps, such as iowaits and
61 * memory stalls. As a result, it has to distinguish between sleeps,
62 * where a task's runnable state changes, and requeues, where a task
63 * and its state are being moved between CPUs and runqueues.
64 */
psi_enqueue(struct task_struct * p,bool wakeup)65 static inline void psi_enqueue(struct task_struct *p, bool wakeup)
66 {
67 int clear = 0, set = TSK_RUNNING;
68
69 if (static_branch_likely(&psi_disabled))
70 return;
71
72 if (!wakeup || p->sched_psi_wake_requeue) {
73 if (p->in_memstall)
74 set |= TSK_MEMSTALL;
75 if (p->sched_psi_wake_requeue)
76 p->sched_psi_wake_requeue = 0;
77 } else {
78 if (p->in_iowait)
79 clear |= TSK_IOWAIT;
80 }
81
82 psi_task_change(p, clear, set);
83 }
84
psi_dequeue(struct task_struct * p,bool sleep)85 static inline void psi_dequeue(struct task_struct *p, bool sleep)
86 {
87 int clear = TSK_RUNNING;
88
89 if (static_branch_likely(&psi_disabled))
90 return;
91
92 /*
93 * A voluntary sleep is a dequeue followed by a task switch. To
94 * avoid walking all ancestors twice, psi_task_switch() handles
95 * TSK_RUNNING and TSK_IOWAIT for us when it moves TSK_ONCPU.
96 * Do nothing here.
97 */
98 if (sleep)
99 return;
100
101 if (p->in_memstall)
102 clear |= TSK_MEMSTALL;
103
104 psi_task_change(p, clear, 0);
105 }
106
psi_ttwu_dequeue(struct task_struct * p)107 static inline void psi_ttwu_dequeue(struct task_struct *p)
108 {
109 if (static_branch_likely(&psi_disabled))
110 return;
111 /*
112 * Is the task being migrated during a wakeup? Make sure to
113 * deregister its sleep-persistent psi states from the old
114 * queue, and let psi_enqueue() know it has to requeue.
115 */
116 if (unlikely(p->in_iowait || p->in_memstall)) {
117 struct rq_flags rf;
118 struct rq *rq;
119 int clear = 0;
120
121 if (p->in_iowait)
122 clear |= TSK_IOWAIT;
123 if (p->in_memstall)
124 clear |= TSK_MEMSTALL;
125
126 rq = __task_rq_lock(p, &rf);
127 psi_task_change(p, clear, 0);
128 p->sched_psi_wake_requeue = 1;
129 __task_rq_unlock(rq, &rf);
130 }
131 }
132
psi_sched_switch(struct task_struct * prev,struct task_struct * next,bool sleep)133 static inline void psi_sched_switch(struct task_struct *prev,
134 struct task_struct *next,
135 bool sleep)
136 {
137 if (static_branch_likely(&psi_disabled))
138 return;
139
140 psi_task_switch(prev, next, sleep);
141 }
142
143 #else /* CONFIG_PSI */
psi_enqueue(struct task_struct * p,bool wakeup)144 static inline void psi_enqueue(struct task_struct *p, bool wakeup) {}
psi_dequeue(struct task_struct * p,bool sleep)145 static inline void psi_dequeue(struct task_struct *p, bool sleep) {}
psi_ttwu_dequeue(struct task_struct * p)146 static inline void psi_ttwu_dequeue(struct task_struct *p) {}
psi_sched_switch(struct task_struct * prev,struct task_struct * next,bool sleep)147 static inline void psi_sched_switch(struct task_struct *prev,
148 struct task_struct *next,
149 bool sleep) {}
150 #endif /* CONFIG_PSI */
151
152 #ifdef CONFIG_SCHED_INFO
153 /*
154 * We are interested in knowing how long it was from the *first* time a
155 * task was queued to the time that it finally hit a CPU, we call this routine
156 * from dequeue_task() to account for possible rq->clock skew across CPUs. The
157 * delta taken on each CPU would annul the skew.
158 */
sched_info_dequeue(struct rq * rq,struct task_struct * t)159 static inline void sched_info_dequeue(struct rq *rq, struct task_struct *t)
160 {
161 unsigned long long delta = 0;
162
163 if (!t->sched_info.last_queued)
164 return;
165
166 delta = rq_clock(rq) - t->sched_info.last_queued;
167 t->sched_info.last_queued = 0;
168 t->sched_info.run_delay += delta;
169
170 rq_sched_info_dequeue(rq, delta);
171 }
172
173 /*
174 * Called when a task finally hits the CPU. We can now calculate how
175 * long it was waiting to run. We also note when it began so that we
176 * can keep stats on how long its timeslice is.
177 */
sched_info_arrive(struct rq * rq,struct task_struct * t)178 static void sched_info_arrive(struct rq *rq, struct task_struct *t)
179 {
180 unsigned long long now, delta = 0;
181
182 if (!t->sched_info.last_queued)
183 return;
184
185 now = rq_clock(rq);
186 delta = now - t->sched_info.last_queued;
187 t->sched_info.last_queued = 0;
188 t->sched_info.run_delay += delta;
189 t->sched_info.last_arrival = now;
190 t->sched_info.pcount++;
191
192 rq_sched_info_arrive(rq, delta);
193 }
194
195 /*
196 * This function is only called from enqueue_task(), but also only updates
197 * the timestamp if it is already not set. It's assumed that
198 * sched_info_dequeue() will clear that stamp when appropriate.
199 */
sched_info_enqueue(struct rq * rq,struct task_struct * t)200 static inline void sched_info_enqueue(struct rq *rq, struct task_struct *t)
201 {
202 if (!t->sched_info.last_queued)
203 t->sched_info.last_queued = rq_clock(rq);
204 }
205
206 /*
207 * Called when a process ceases being the active-running process involuntarily
208 * due, typically, to expiring its time slice (this may also be called when
209 * switching to the idle task). Now we can calculate how long we ran.
210 * Also, if the process is still in the TASK_RUNNING state, call
211 * sched_info_enqueue() to mark that it has now again started waiting on
212 * the runqueue.
213 */
sched_info_depart(struct rq * rq,struct task_struct * t)214 static inline void sched_info_depart(struct rq *rq, struct task_struct *t)
215 {
216 unsigned long long delta = rq_clock(rq) - t->sched_info.last_arrival;
217
218 rq_sched_info_depart(rq, delta);
219
220 if (task_is_running(t))
221 sched_info_enqueue(rq, t);
222 }
223
224 /*
225 * Called when tasks are switched involuntarily due, typically, to expiring
226 * their time slice. (This may also be called when switching to or from
227 * the idle task.) We are only called when prev != next.
228 */
229 static inline void
sched_info_switch(struct rq * rq,struct task_struct * prev,struct task_struct * next)230 sched_info_switch(struct rq *rq, struct task_struct *prev, struct task_struct *next)
231 {
232 /*
233 * prev now departs the CPU. It's not interesting to record
234 * stats about how efficient we were at scheduling the idle
235 * process, however.
236 */
237 if (prev != rq->idle)
238 sched_info_depart(rq, prev);
239
240 if (next != rq->idle)
241 sched_info_arrive(rq, next);
242 }
243
244 #else /* !CONFIG_SCHED_INFO: */
245 # define sched_info_enqueue(rq, t) do { } while (0)
246 # define sched_info_dequeue(rq, t) do { } while (0)
247 # define sched_info_switch(rq, t, next) do { } while (0)
248 #endif /* CONFIG_SCHED_INFO */
249
