Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
sched: Provide idle_rq() helper
A fix for the dl_server 'requires' idle_cpu() usage, which made me
note that it and available_idle_cpu() are extern function calls.
And while idle_cpu() is used outside of kernel/sched/,
available_idle_cpu() is not.
This makes it hard to make idle_cpu() an inline helper, so provide
idle_rq() and implement idle_cpu() and available_idle_cpu() using
that.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
+23
-30
-1
include/linux/sched.h
-1
include/linux/sched.h
···
1874
1874
extern int can_nice(const struct task_struct *p, const int nice);
1875
1875
extern int task_curr(const struct task_struct *p);
1876
1876
extern int idle_cpu(int cpu);
1877
-
extern int available_idle_cpu(int cpu);
1878
1877
extern int sched_setscheduler(struct task_struct *, int, const struct sched_param *);
1879
1878
extern int sched_setscheduler_nocheck(struct task_struct *, int, const struct sched_param *);
1880
1879
extern void sched_set_fifo(struct task_struct *p);
+22
kernel/sched/sched.h
+22
kernel/sched/sched.h
···
1364
1364
#define cpu_curr(cpu) (cpu_rq(cpu)->curr)
1365
1365
#define raw_rq() raw_cpu_ptr(&runqueues)
1366
1366
1367
+
static inline bool idle_rq(struct rq *rq)
1368
+
{
1369
+
return rq->curr == rq->idle && !rq->nr_running && !rq->ttwu_pending;
1370
+
}
1371
+
1372
+
/**
1373
+
* available_idle_cpu - is a given CPU idle for enqueuing work.
1374
+
* @cpu: the CPU in question.
1375
+
*
1376
+
* Return: 1 if the CPU is currently idle. 0 otherwise.
1377
+
*/
1378
+
static inline bool available_idle_cpu(int cpu)
1379
+
{
1380
+
if (!idle_rq(cpu_rq(cpu)))
1381
+
return 0;
1382
+
1383
+
if (vcpu_is_preempted(cpu))
1384
+
return 0;
1385
+
1386
+
return 1;
1387
+
}
1388
+
1367
1389
#ifdef CONFIG_SCHED_PROXY_EXEC
1368
1390
static inline void rq_set_donor(struct rq *rq, struct task_struct *t)
1369
1391
{
+1
-29
kernel/sched/syscalls.c
+1
-29
kernel/sched/syscalls.c
···
180
180
*/
181
181
int idle_cpu(int cpu)
182
182
{
183
-
struct rq *rq = cpu_rq(cpu);
184
-
185
-
if (rq->curr != rq->idle)
186
-
return 0;
187
-
188
-
if (rq->nr_running)
189
-
return 0;
190
-
191
-
if (rq->ttwu_pending)
192
-
return 0;
193
-
194
-
return 1;
195
-
}
196
-
197
-
/**
198
-
* available_idle_cpu - is a given CPU idle for enqueuing work.
199
-
* @cpu: the CPU in question.
200
-
*
201
-
* Return: 1 if the CPU is currently idle. 0 otherwise.
202
-
*/
203
-
int available_idle_cpu(int cpu)
204
-
{
205
-
if (!idle_cpu(cpu))
206
-
return 0;
207
-
208
-
if (vcpu_is_preempted(cpu))
209
-
return 0;
210
-
211
-
return 1;
183
+
return idle_rq(cpu_rq(cpu));
212
184
}
213
185
214
186
/**