FreeBSD kernel kern code
sched_ule.c
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1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3  *
4  * Copyright (c) 2002-2007, Jeffrey Roberson <jeff@freebsd.org>
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  * notice unmodified, this list of conditions, and the following
12  * disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  * notice, this list of conditions and the following disclaimer in the
15  * documentation and/or other materials provided with the distribution.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27  */
28 
29 /*
30  * This file implements the ULE scheduler. ULE supports independent CPU
31  * run queues and fine grain locking. It has superior interactive
32  * performance under load even on uni-processor systems.
33  *
34  * etymology:
35  * ULE is the last three letters in schedule. It owes its name to a
36  * generic user created for a scheduling system by Paul Mikesell at
37  * Isilon Systems and a general lack of creativity on the part of the author.
38  */
39 
40 #include <sys/cdefs.h>
41 __FBSDID("$FreeBSD: head/sys/kern/sched_ule.c 327895 2018-01-12 22:48:23Z jeff $");
42 
43 #include "opt_hwpmc_hooks.h"
44 #include "opt_sched.h"
45 
46 #include <sys/param.h>
47 #include <sys/systm.h>
48 #include <sys/kdb.h>
49 #include <sys/kernel.h>
50 #include <sys/ktr.h>
51 #include <sys/limits.h>
52 #include <sys/lock.h>
53 #include <sys/mutex.h>
54 #include <sys/proc.h>
55 #include <sys/resource.h>
56 #include <sys/resourcevar.h>
57 #include <sys/sched.h>
58 #include <sys/sdt.h>
59 #include <sys/smp.h>
60 #include <sys/sx.h>
61 #include <sys/sysctl.h>
62 #include <sys/sysproto.h>
63 #include <sys/turnstile.h>
64 #include <sys/umtx.h>
65 #include <sys/vmmeter.h>
66 #include <sys/cpuset.h>
67 #include <sys/sbuf.h>
68 
69 #ifdef HWPMC_HOOKS
70 #include <sys/pmckern.h>
71 #endif
72 
73 #ifdef KDTRACE_HOOKS
74 #include <sys/dtrace_bsd.h>
75 int dtrace_vtime_active;
76 dtrace_vtime_switch_func_t dtrace_vtime_switch_func;
77 #endif
78 
79 #include <machine/cpu.h>
80 #include <machine/smp.h>
81 
82 #define KTR_ULE 0
83 
84 #define TS_NAME_LEN (MAXCOMLEN + sizeof(" td ") + sizeof(__XSTRING(UINT_MAX)))
85 #define TDQ_NAME_LEN (sizeof("sched lock ") + sizeof(__XSTRING(MAXCPU)))
86 #define TDQ_LOADNAME_LEN (sizeof("CPU ") + sizeof(__XSTRING(MAXCPU)) - 1 + sizeof(" load"))
87 
88 /*
89  * Thread scheduler specific section. All fields are protected
90  * by the thread lock.
91  */
92 struct td_sched {
93  struct runq *ts_runq; /* Run-queue we're queued on. */
94  short ts_flags; /* TSF_* flags. */
95  int ts_cpu; /* CPU that we have affinity for. */
96  int ts_rltick; /* Real last tick, for affinity. */
97  int ts_slice; /* Ticks of slice remaining. */
98  u_int ts_slptime; /* Number of ticks we vol. slept */
99  u_int ts_runtime; /* Number of ticks we were running */
100  int ts_ltick; /* Last tick that we were running on */
101  int ts_ftick; /* First tick that we were running on */
102  int ts_ticks; /* Tick count */
103 #ifdef KTR
104  char ts_name[TS_NAME_LEN];
105 #endif
106 };
107 /* flags kept in ts_flags */
108 #define TSF_BOUND 0x0001 /* Thread can not migrate. */
109 #define TSF_XFERABLE 0x0002 /* Thread was added as transferable. */
110 
111 #define THREAD_CAN_MIGRATE(td) ((td)->td_pinned == 0)
112 #define THREAD_CAN_SCHED(td, cpu) \
113  CPU_ISSET((cpu), &(td)->td_cpuset->cs_mask)
114 
115 _Static_assert(sizeof(struct thread) + sizeof(struct td_sched) <=
116  sizeof(struct thread0_storage),
117  "increase struct thread0_storage.t0st_sched size");
118 
119 /*
120  * Priority ranges used for interactive and non-interactive timeshare
121  * threads. The timeshare priorities are split up into four ranges.
122  * The first range handles interactive threads. The last three ranges
123  * (NHALF, x, and NHALF) handle non-interactive threads with the outer
124  * ranges supporting nice values.
125  */
126 #define PRI_TIMESHARE_RANGE (PRI_MAX_TIMESHARE - PRI_MIN_TIMESHARE + 1)
127 #define PRI_INTERACT_RANGE ((PRI_TIMESHARE_RANGE - SCHED_PRI_NRESV) / 2)
128 #define PRI_BATCH_RANGE (PRI_TIMESHARE_RANGE - PRI_INTERACT_RANGE)
129 
130 #define PRI_MIN_INTERACT PRI_MIN_TIMESHARE
131 #define PRI_MAX_INTERACT (PRI_MIN_TIMESHARE + PRI_INTERACT_RANGE - 1)
132 #define PRI_MIN_BATCH (PRI_MIN_TIMESHARE + PRI_INTERACT_RANGE)
133 #define PRI_MAX_BATCH PRI_MAX_TIMESHARE
134 
135 /*
136  * Cpu percentage computation macros and defines.
137  *
138  * SCHED_TICK_SECS: Number of seconds to average the cpu usage across.
139  * SCHED_TICK_TARG: Number of hz ticks to average the cpu usage across.
140  * SCHED_TICK_MAX: Maximum number of ticks before scaling back.
141  * SCHED_TICK_SHIFT: Shift factor to avoid rounding away results.
142  * SCHED_TICK_HZ: Compute the number of hz ticks for a given ticks count.
143  * SCHED_TICK_TOTAL: Gives the amount of time we've been recording ticks.
144  */
145 #define SCHED_TICK_SECS 10
146 #define SCHED_TICK_TARG (hz * SCHED_TICK_SECS)
147 #define SCHED_TICK_MAX (SCHED_TICK_TARG + hz)
148 #define SCHED_TICK_SHIFT 10
149 #define SCHED_TICK_HZ(ts) ((ts)->ts_ticks >> SCHED_TICK_SHIFT)
150 #define SCHED_TICK_TOTAL(ts) (max((ts)->ts_ltick - (ts)->ts_ftick, hz))
151 
152 /*
153  * These macros determine priorities for non-interactive threads. They are
154  * assigned a priority based on their recent cpu utilization as expressed
155  * by the ratio of ticks to the tick total. NHALF priorities at the start
156  * and end of the MIN to MAX timeshare range are only reachable with negative
157  * or positive nice respectively.
158  *
159  * PRI_RANGE: Priority range for utilization dependent priorities.
160  * PRI_NRESV: Number of nice values.
161  * PRI_TICKS: Compute a priority in PRI_RANGE from the ticks count and total.
162  * PRI_NICE: Determines the part of the priority inherited from nice.
163  */
164 #define SCHED_PRI_NRESV (PRIO_MAX - PRIO_MIN)
165 #define SCHED_PRI_NHALF (SCHED_PRI_NRESV / 2)
166 #define SCHED_PRI_MIN (PRI_MIN_BATCH + SCHED_PRI_NHALF)
167 #define SCHED_PRI_MAX (PRI_MAX_BATCH - SCHED_PRI_NHALF)
168 #define SCHED_PRI_RANGE (SCHED_PRI_MAX - SCHED_PRI_MIN + 1)
169 #define SCHED_PRI_TICKS(ts) \
170  (SCHED_TICK_HZ((ts)) / \
171  (roundup(SCHED_TICK_TOTAL((ts)), SCHED_PRI_RANGE) / SCHED_PRI_RANGE))
172 #define SCHED_PRI_NICE(nice) (nice)
173 
174 /*
175  * These determine the interactivity of a process. Interactivity differs from
176  * cpu utilization in that it expresses the voluntary time slept vs time ran
177  * while cpu utilization includes all time not running. This more accurately
178  * models the intent of the thread.
179  *
180  * SLP_RUN_MAX: Maximum amount of sleep time + run time we'll accumulate
181  * before throttling back.
182  * SLP_RUN_FORK: Maximum slp+run time to inherit at fork time.
183  * INTERACT_MAX: Maximum interactivity value. Smaller is better.
184  * INTERACT_THRESH: Threshold for placement on the current runq.
185  */
186 #define SCHED_SLP_RUN_MAX ((hz * 5) << SCHED_TICK_SHIFT)
187 #define SCHED_SLP_RUN_FORK ((hz / 2) << SCHED_TICK_SHIFT)
188 #define SCHED_INTERACT_MAX (100)
189 #define SCHED_INTERACT_HALF (SCHED_INTERACT_MAX / 2)
190 #define SCHED_INTERACT_THRESH (30)
191 
192 /*
193  * These parameters determine the slice behavior for batch work.
194  */
195 #define SCHED_SLICE_DEFAULT_DIVISOR 10 /* ~94 ms, 12 stathz ticks. */
196 #define SCHED_SLICE_MIN_DIVISOR 6 /* DEFAULT/MIN = ~16 ms. */
197 
198 /* Flags kept in td_flags. */
199 #define TDF_SLICEEND TDF_SCHED2 /* Thread time slice is over. */
200 
201 /*
202  * tickincr: Converts a stathz tick into a hz domain scaled by
203  * the shift factor. Without the shift the error rate
204  * due to rounding would be unacceptably high.
205  * realstathz: stathz is sometimes 0 and run off of hz.
206  * sched_slice: Runtime of each thread before rescheduling.
207  * preempt_thresh: Priority threshold for preemption and remote IPIs.
208  */
210 static int tickincr = 8 << SCHED_TICK_SHIFT;
211 static int realstathz = 127; /* reset during boot. */
212 static int sched_slice = 10; /* reset during boot. */
213 static int sched_slice_min = 1; /* reset during boot. */
214 #ifdef PREEMPTION
215 #ifdef FULL_PREEMPTION
216 static int preempt_thresh = PRI_MAX_IDLE;
217 #else
218 static int preempt_thresh = PRI_MIN_KERN;
219 #endif
220 #else
221 static int preempt_thresh = 0;
222 #endif
224 static int sched_idlespins = 10000;
225 static int sched_idlespinthresh = -1;
226 
227 /*
228  * tdq - per processor runqs and statistics. All fields are protected by the
229  * tdq_lock. The load and lowpri may be accessed without to avoid excess
230  * locking in sched_pickcpu();
231  */
232 struct tdq {
233  /*
234  * Ordered to improve efficiency of cpu_search() and switch().
235  * tdq_lock is padded to avoid false sharing with tdq_load and
236  * tdq_cpu_idle.
237  */
238  struct mtx_padalign tdq_lock; /* run queue lock. */
239  struct cpu_group *tdq_cg; /* Pointer to cpu topology. */
240  volatile int tdq_load; /* Aggregate load. */
241  volatile int tdq_cpu_idle; /* cpu_idle() is active. */
242  int tdq_sysload; /* For loadavg, !ITHD load. */
243  int tdq_transferable; /* Transferable thread count. */
244  short tdq_switchcnt; /* Switches this tick. */
245  short tdq_oldswitchcnt; /* Switches last tick. */
246  u_char tdq_lowpri; /* Lowest priority thread. */
247  u_char tdq_ipipending; /* IPI pending. */
248  u_char tdq_idx; /* Current insert index. */
249  u_char tdq_ridx; /* Current removal index. */
250  struct runq tdq_realtime; /* real-time run queue. */
251  struct runq tdq_timeshare; /* timeshare run queue. */
252  struct runq tdq_idle; /* Queue of IDLE threads. */
254 #ifdef KTR
255  char tdq_loadname[TDQ_LOADNAME_LEN];
256 #endif
257 } __aligned(64);
258 
259 /* Idle thread states and config. */
260 #define TDQ_RUNNING 1
261 #define TDQ_IDLE 2
262 
263 #ifdef SMP
264 struct cpu_group *cpu_top; /* CPU topology */
265 
266 #define SCHED_AFFINITY_DEFAULT (max(1, hz / 1000))
267 #define SCHED_AFFINITY(ts, t) ((ts)->ts_rltick > ticks - ((t) * affinity))
268 
269 /*
270  * Run-time tunables.
271  */
272 static int rebalance = 1;
273 static int balance_interval = 128; /* Default set in sched_initticks(). */
274 static int affinity;
275 static int steal_idle = 1;
276 static int steal_thresh = 2;
277 
278 /*
279  * One thread queue per processor.
280  */
281 static struct tdq tdq_cpu[MAXCPU];
282 static struct tdq *balance_tdq;
283 static int balance_ticks;
284 static DPCPU_DEFINE(uint32_t, randomval);
285 
286 #define TDQ_SELF() (&tdq_cpu[PCPU_GET(cpuid)])
287 #define TDQ_CPU(x) (&tdq_cpu[(x)])
288 #define TDQ_ID(x) ((int)((x) - tdq_cpu))
289 #else /* !SMP */
290 static struct tdq tdq_cpu;
291 
292 #define TDQ_ID(x) (0)
293 #define TDQ_SELF() (&tdq_cpu)
294 #define TDQ_CPU(x) (&tdq_cpu)
295 #endif
296 
297 #define TDQ_LOCK_ASSERT(t, type) mtx_assert(TDQ_LOCKPTR((t)), (type))
298 #define TDQ_LOCK(t) mtx_lock_spin(TDQ_LOCKPTR((t)))
299 #define TDQ_LOCK_FLAGS(t, f) mtx_lock_spin_flags(TDQ_LOCKPTR((t)), (f))
300 #define TDQ_UNLOCK(t) mtx_unlock_spin(TDQ_LOCKPTR((t)))
301 #define TDQ_LOCKPTR(t) ((struct mtx *)(&(t)->tdq_lock))
302 
303 static void sched_priority(struct thread *);
304 static void sched_thread_priority(struct thread *, u_char);
305 static int sched_interact_score(struct thread *);
306 static void sched_interact_update(struct thread *);
307 static void sched_interact_fork(struct thread *);
308 static void sched_pctcpu_update(struct td_sched *, int);
309 
310 /* Operations on per processor queues */
311 static struct thread *tdq_choose(struct tdq *);
312 static void tdq_setup(struct tdq *);
313 static void tdq_load_add(struct tdq *, struct thread *);
314 static void tdq_load_rem(struct tdq *, struct thread *);
315 static __inline void tdq_runq_add(struct tdq *, struct thread *, int);
316 static __inline void tdq_runq_rem(struct tdq *, struct thread *);
317 static inline int sched_shouldpreempt(int, int, int);
318 void tdq_print(int cpu);
319 static void runq_print(struct runq *rq);
320 static void tdq_add(struct tdq *, struct thread *, int);
321 #ifdef SMP
322 static int tdq_move(struct tdq *, struct tdq *);
323 static int tdq_idled(struct tdq *);
324 static void tdq_notify(struct tdq *, struct thread *);
325 static struct thread *tdq_steal(struct tdq *, int);
326 static struct thread *runq_steal(struct runq *, int);
327 static int sched_pickcpu(struct thread *, int);
328 static void sched_balance(void);
329 static int sched_balance_pair(struct tdq *, struct tdq *);
330 static inline struct tdq *sched_setcpu(struct thread *, int, int);
331 static inline void thread_unblock_switch(struct thread *, struct mtx *);
332 static struct mtx *sched_switch_migrate(struct tdq *, struct thread *, int);
333 static int sysctl_kern_sched_topology_spec(SYSCTL_HANDLER_ARGS);
334 static int sysctl_kern_sched_topology_spec_internal(struct sbuf *sb,
335  struct cpu_group *cg, int indent);
336 #endif
337 
338 static void sched_setup(void *dummy);
339 SYSINIT(sched_setup, SI_SUB_RUN_QUEUE, SI_ORDER_FIRST, sched_setup, NULL);
340 
341 static void sched_initticks(void *dummy);
342 SYSINIT(sched_initticks, SI_SUB_CLOCKS, SI_ORDER_THIRD, sched_initticks,
343  NULL);
344 
345 SDT_PROVIDER_DEFINE(sched);
346 
347 SDT_PROBE_DEFINE3(sched, , , change__pri, "struct thread *",
348  "struct proc *", "uint8_t");
349 SDT_PROBE_DEFINE3(sched, , , dequeue, "struct thread *",
350  "struct proc *", "void *");
351 SDT_PROBE_DEFINE4(sched, , , enqueue, "struct thread *",
352  "struct proc *", "void *", "int");
353 SDT_PROBE_DEFINE4(sched, , , lend__pri, "struct thread *",
354  "struct proc *", "uint8_t", "struct thread *");
355 SDT_PROBE_DEFINE2(sched, , , load__change, "int", "int");
356 SDT_PROBE_DEFINE2(sched, , , off__cpu, "struct thread *",
357  "struct proc *");
358 SDT_PROBE_DEFINE(sched, , , on__cpu);
359 SDT_PROBE_DEFINE(sched, , , remain__cpu);
360 SDT_PROBE_DEFINE2(sched, , , surrender, "struct thread *",
361  "struct proc *");
362 
363 /*
364  * Print the threads waiting on a run-queue.
365  */
366 static void
367 runq_print(struct runq *rq)
368 {
369  struct rqhead *rqh;
370  struct thread *td;
371  int pri;
372  int j;
373  int i;
374 
375  for (i = 0; i < RQB_LEN; i++) {
376  printf("\t\trunq bits %d 0x%zx\n",
377  i, rq->rq_status.rqb_bits[i]);
378  for (j = 0; j < RQB_BPW; j++)
379  if (rq->rq_status.rqb_bits[i] & (1ul << j)) {
380  pri = j + (i << RQB_L2BPW);
381  rqh = &rq->rq_queues[pri];
382  TAILQ_FOREACH(td, rqh, td_runq) {
383  printf("\t\t\ttd %p(%s) priority %d rqindex %d pri %d\n",
384  td, td->td_name, td->td_priority,
385  td->td_rqindex, pri);
386  }
387  }
388  }
389 }
390 
391 /*
392  * Print the status of a per-cpu thread queue. Should be a ddb show cmd.
393  */
394 void
395 tdq_print(int cpu)
396 {
397  struct tdq *tdq;
398 
399  tdq = TDQ_CPU(cpu);
400 
401  printf("tdq %d:\n", TDQ_ID(tdq));
402  printf("\tlock %p\n", TDQ_LOCKPTR(tdq));
403  printf("\tLock name: %s\n", tdq->tdq_name);
404  printf("\tload: %d\n", tdq->tdq_load);
405  printf("\tswitch cnt: %d\n", tdq->tdq_switchcnt);
406  printf("\told switch cnt: %d\n", tdq->tdq_oldswitchcnt);
407  printf("\ttimeshare idx: %d\n", tdq->tdq_idx);
408  printf("\ttimeshare ridx: %d\n", tdq->tdq_ridx);
409  printf("\tload transferable: %d\n", tdq->tdq_transferable);
410  printf("\tlowest priority: %d\n", tdq->tdq_lowpri);
411  printf("\trealtime runq:\n");
412  runq_print(&tdq->tdq_realtime);
413  printf("\ttimeshare runq:\n");
414  runq_print(&tdq->tdq_timeshare);
415  printf("\tidle runq:\n");
416  runq_print(&tdq->tdq_idle);
417 }
418 
419 static inline int
420 sched_shouldpreempt(int pri, int cpri, int remote)
421 {
422  /*
423  * If the new priority is not better than the current priority there is
424  * nothing to do.
425  */
426  if (pri >= cpri)
427  return (0);
428  /*
429  * Always preempt idle.
430  */
431  if (cpri >= PRI_MIN_IDLE)
432  return (1);
433  /*
434  * If preemption is disabled don't preempt others.
435  */
436  if (preempt_thresh == 0)
437  return (0);
438  /*
439  * Preempt if we exceed the threshold.
440  */
441  if (pri <= preempt_thresh)
442  return (1);
443  /*
444  * If we're interactive or better and there is non-interactive
445  * or worse running preempt only remote processors.
446  */
447  if (remote && pri <= PRI_MAX_INTERACT && cpri > PRI_MAX_INTERACT)
448  return (1);
449  return (0);
450 }
451 
452 /*
453  * Add a thread to the actual run-queue. Keeps transferable counts up to
454  * date with what is actually on the run-queue. Selects the correct
455  * queue position for timeshare threads.
456  */
457 static __inline void
458 tdq_runq_add(struct tdq *tdq, struct thread *td, int flags)
459 {
460  struct td_sched *ts;
461  u_char pri;
462 
463  TDQ_LOCK_ASSERT(tdq, MA_OWNED);
464  THREAD_LOCK_ASSERT(td, MA_OWNED);
465 
466  pri = td->td_priority;
467  ts = td_get_sched(td);
468  TD_SET_RUNQ(td);
469  if (THREAD_CAN_MIGRATE(td)) {
470  tdq->tdq_transferable++;
471  ts->ts_flags |= TSF_XFERABLE;
472  }
473  if (pri < PRI_MIN_BATCH) {
474  ts->ts_runq = &tdq->tdq_realtime;
475  } else if (pri <= PRI_MAX_BATCH) {
476  ts->ts_runq = &tdq->tdq_timeshare;
477  KASSERT(pri <= PRI_MAX_BATCH && pri >= PRI_MIN_BATCH,
478  ("Invalid priority %d on timeshare runq", pri));
479  /*
480  * This queue contains only priorities between MIN and MAX
481  * realtime. Use the whole queue to represent these values.
482  */
483  if ((flags & (SRQ_BORROWING|SRQ_PREEMPTED)) == 0) {
484  pri = RQ_NQS * (pri - PRI_MIN_BATCH) / PRI_BATCH_RANGE;
485  pri = (pri + tdq->tdq_idx) % RQ_NQS;
486  /*
487  * This effectively shortens the queue by one so we
488  * can have a one slot difference between idx and
489  * ridx while we wait for threads to drain.
490  */
491  if (tdq->tdq_ridx != tdq->tdq_idx &&
492  pri == tdq->tdq_ridx)
493  pri = (unsigned char)(pri - 1) % RQ_NQS;
494  } else
495  pri = tdq->tdq_ridx;
496  runq_add_pri(ts->ts_runq, td, pri, flags);
497  return;
498  } else
499  ts->ts_runq = &tdq->tdq_idle;
500  runq_add(ts->ts_runq, td, flags);
501 }
502 
503 /*
504  * Remove a thread from a run-queue. This typically happens when a thread
505  * is selected to run. Running threads are not on the queue and the
506  * transferable count does not reflect them.
507  */
508 static __inline void
509 tdq_runq_rem(struct tdq *tdq, struct thread *td)
510 {
511  struct td_sched *ts;
512 
513  ts = td_get_sched(td);
514  TDQ_LOCK_ASSERT(tdq, MA_OWNED);
515  KASSERT(ts->ts_runq != NULL,
516  ("tdq_runq_remove: thread %p null ts_runq", td));
517  if (ts->ts_flags & TSF_XFERABLE) {
518  tdq->tdq_transferable--;
519  ts->ts_flags &= ~TSF_XFERABLE;
520  }
521  if (ts->ts_runq == &tdq->tdq_timeshare) {
522  if (tdq->tdq_idx != tdq->tdq_ridx)
523  runq_remove_idx(ts->ts_runq, td, &tdq->tdq_ridx);
524  else
525  runq_remove_idx(ts->ts_runq, td, NULL);
526  } else
527  runq_remove(ts->ts_runq, td);
528 }
529 
530 /*
531  * Load is maintained for all threads RUNNING and ON_RUNQ. Add the load
532  * for this thread to the referenced thread queue.
533  */
534 static void
535 tdq_load_add(struct tdq *tdq, struct thread *td)
536 {
537 
538  TDQ_LOCK_ASSERT(tdq, MA_OWNED);
539  THREAD_LOCK_ASSERT(td, MA_OWNED);
540 
541  tdq->tdq_load++;
542  if ((td->td_flags & TDF_NOLOAD) == 0)
543  tdq->tdq_sysload++;
544  KTR_COUNTER0(KTR_SCHED, "load", tdq->tdq_loadname, tdq->tdq_load);
545  SDT_PROBE2(sched, , , load__change, (int)TDQ_ID(tdq), tdq->tdq_load);
546 }
547 
548 /*
549  * Remove the load from a thread that is transitioning to a sleep state or
550  * exiting.
551  */
552 static void
553 tdq_load_rem(struct tdq *tdq, struct thread *td)
554 {
555 
556  THREAD_LOCK_ASSERT(td, MA_OWNED);
557  TDQ_LOCK_ASSERT(tdq, MA_OWNED);
558  KASSERT(tdq->tdq_load != 0,
559  ("tdq_load_rem: Removing with 0 load on queue %d", TDQ_ID(tdq)));
560 
561  tdq->tdq_load--;
562  if ((td->td_flags & TDF_NOLOAD) == 0)
563  tdq->tdq_sysload--;
564  KTR_COUNTER0(KTR_SCHED, "load", tdq->tdq_loadname, tdq->tdq_load);
565  SDT_PROBE2(sched, , , load__change, (int)TDQ_ID(tdq), tdq->tdq_load);
566 }
567 
568 /*
569  * Bound timeshare latency by decreasing slice size as load increases. We
570  * consider the maximum latency as the sum of the threads waiting to run
571  * aside from curthread and target no more than sched_slice latency but
572  * no less than sched_slice_min runtime.
573  */
574 static inline int
575 tdq_slice(struct tdq *tdq)
576 {
577  int load;
578 
579  /*
580  * It is safe to use sys_load here because this is called from
581  * contexts where timeshare threads are running and so there
582  * cannot be higher priority load in the system.
583  */
584  load = tdq->tdq_sysload - 1;
585  if (load >= SCHED_SLICE_MIN_DIVISOR)
586  return (sched_slice_min);
587  if (load <= 1)
588  return (sched_slice);
589  return (sched_slice / load);
590 }
591 
592 /*
593  * Set lowpri to its exact value by searching the run-queue and
594  * evaluating curthread. curthread may be passed as an optimization.
595  */
596 static void
597 tdq_setlowpri(struct tdq *tdq, struct thread *ctd)
598 {
599  struct thread *td;
600 
601  TDQ_LOCK_ASSERT(tdq, MA_OWNED);
602  if (ctd == NULL)
603  ctd = pcpu_find(TDQ_ID(tdq))->pc_curthread;
604  td = tdq_choose(tdq);
605  if (td == NULL || td->td_priority > ctd->td_priority)
606  tdq->tdq_lowpri = ctd->td_priority;
607  else
608  tdq->tdq_lowpri = td->td_priority;
609 }
610 
611 #ifdef SMP
612 /*
613  * We need some randomness. Implement a classic Linear Congruential
614  * Generator X_{n+1}=(aX_n+c) mod m. These values are optimized for
615  * m = 2^32, a = 69069 and c = 5. We only return the upper 16 bits
616  * of the random state (in the low bits of our answer) to keep
617  * the maximum randomness.
618  */
619 static uint32_t
620 sched_random(void)
621 {
622  uint32_t *rndptr;
623 
624  rndptr = DPCPU_PTR(randomval);
625  *rndptr = *rndptr * 69069 + 5;
626 
627  return (*rndptr >> 16);
628 }
629 
630 struct cpu_search {
631  cpuset_t cs_mask;
632  u_int cs_prefer;
633  int cs_pri; /* Min priority for low. */
634  int cs_limit; /* Max load for low, min load for high. */
635  int cs_cpu;
636  int cs_load;
637 };
638 
639 #define CPU_SEARCH_LOWEST 0x1
640 #define CPU_SEARCH_HIGHEST 0x2
641 #define CPU_SEARCH_BOTH (CPU_SEARCH_LOWEST|CPU_SEARCH_HIGHEST)
642 
643 #define CPUSET_FOREACH(cpu, mask) \
644  for ((cpu) = 0; (cpu) <= mp_maxid; (cpu)++) \
645  if (CPU_ISSET(cpu, &mask))
646 
647 static __always_inline int cpu_search(const struct cpu_group *cg,
648  struct cpu_search *low, struct cpu_search *high, const int match);
649 int __noinline cpu_search_lowest(const struct cpu_group *cg,
650  struct cpu_search *low);
651 int __noinline cpu_search_highest(const struct cpu_group *cg,
652  struct cpu_search *high);
653 int __noinline cpu_search_both(const struct cpu_group *cg,
654  struct cpu_search *low, struct cpu_search *high);
655 
656 /*
657  * Search the tree of cpu_groups for the lowest or highest loaded cpu
658  * according to the match argument. This routine actually compares the
659  * load on all paths through the tree and finds the least loaded cpu on
660  * the least loaded path, which may differ from the least loaded cpu in
661  * the system. This balances work among caches and buses.
662  *
663  * This inline is instantiated in three forms below using constants for the
664  * match argument. It is reduced to the minimum set for each case. It is
665  * also recursive to the depth of the tree.
666  */
667 static __always_inline int
668 cpu_search(const struct cpu_group *cg, struct cpu_search *low,
669  struct cpu_search *high, const int match)
670 {
671  struct cpu_search lgroup;
672  struct cpu_search hgroup;
673  cpuset_t cpumask;
674  struct cpu_group *child;
675  struct tdq *tdq;
676  int cpu, i, hload, lload, load, total, rnd;
677 
678  total = 0;
679  cpumask = cg->cg_mask;
680  if (match & CPU_SEARCH_LOWEST) {
681  lload = INT_MAX;
682  lgroup = *low;
683  }
684  if (match & CPU_SEARCH_HIGHEST) {
685  hload = INT_MIN;
686  hgroup = *high;
687  }
688 
689  /* Iterate through the child CPU groups and then remaining CPUs. */
690  for (i = cg->cg_children, cpu = mp_maxid; ; ) {
691  if (i == 0) {
692 #ifdef HAVE_INLINE_FFSL
693  cpu = CPU_FFS(&cpumask) - 1;
694 #else
695  while (cpu >= 0 && !CPU_ISSET(cpu, &cpumask))
696  cpu--;
697 #endif
698  if (cpu < 0)
699  break;
700  child = NULL;
701  } else
702  child = &cg->cg_child[i - 1];
703 
704  if (match & CPU_SEARCH_LOWEST)
705  lgroup.cs_cpu = -1;
706  if (match & CPU_SEARCH_HIGHEST)
707  hgroup.cs_cpu = -1;
708  if (child) { /* Handle child CPU group. */
709  CPU_NAND(&cpumask, &child->cg_mask);
710  switch (match) {
711  case CPU_SEARCH_LOWEST:
712  load = cpu_search_lowest(child, &lgroup);
713  break;
714  case CPU_SEARCH_HIGHEST:
715  load = cpu_search_highest(child, &hgroup);
716  break;
717  case CPU_SEARCH_BOTH:
718  load = cpu_search_both(child, &lgroup, &hgroup);
719  break;
720  }
721  } else { /* Handle child CPU. */
722  CPU_CLR(cpu, &cpumask);
723  tdq = TDQ_CPU(cpu);
724  load = tdq->tdq_load * 256;
725  rnd = sched_random() % 32;
726  if (match & CPU_SEARCH_LOWEST) {
727  if (cpu == low->cs_prefer)
728  load -= 64;
729  /* If that CPU is allowed and get data. */
730  if (tdq->tdq_lowpri > lgroup.cs_pri &&
731  tdq->tdq_load <= lgroup.cs_limit &&
732  CPU_ISSET(cpu, &lgroup.cs_mask)) {
733  lgroup.cs_cpu = cpu;
734  lgroup.cs_load = load - rnd;
735  }
736  }
737  if (match & CPU_SEARCH_HIGHEST)
738  if (tdq->tdq_load >= hgroup.cs_limit &&
739  tdq->tdq_transferable &&
740  CPU_ISSET(cpu, &hgroup.cs_mask)) {
741  hgroup.cs_cpu = cpu;
742  hgroup.cs_load = load - rnd;
743  }
744  }
745  total += load;
746 
747  /* We have info about child item. Compare it. */
748  if (match & CPU_SEARCH_LOWEST) {
749  if (lgroup.cs_cpu >= 0 &&
750  (load < lload ||
751  (load == lload && lgroup.cs_load < low->cs_load))) {
752  lload = load;
753  low->cs_cpu = lgroup.cs_cpu;
754  low->cs_load = lgroup.cs_load;
755  }
756  }
757  if (match & CPU_SEARCH_HIGHEST)
758  if (hgroup.cs_cpu >= 0 &&
759  (load > hload ||
760  (load == hload && hgroup.cs_load > high->cs_load))) {
761  hload = load;
762  high->cs_cpu = hgroup.cs_cpu;
763  high->cs_load = hgroup.cs_load;
764  }
765  if (child) {
766  i--;
767  if (i == 0 && CPU_EMPTY(&cpumask))
768  break;
769  }
770 #ifndef HAVE_INLINE_FFSL
771  else
772  cpu--;
773 #endif
774  }
775  return (total);
776 }
777 
778 /*
779  * cpu_search instantiations must pass constants to maintain the inline
780  * optimization.
781  */
782 int
783 cpu_search_lowest(const struct cpu_group *cg, struct cpu_search *low)
784 {
785  return cpu_search(cg, low, NULL, CPU_SEARCH_LOWEST);
786 }
787 
788 int
789 cpu_search_highest(const struct cpu_group *cg, struct cpu_search *high)
790 {
791  return cpu_search(cg, NULL, high, CPU_SEARCH_HIGHEST);
792 }
793 
794 int
795 cpu_search_both(const struct cpu_group *cg, struct cpu_search *low,
796  struct cpu_search *high)
797 {
798  return cpu_search(cg, low, high, CPU_SEARCH_BOTH);
799 }
800 
801 /*
802  * Find the cpu with the least load via the least loaded path that has a
803  * lowpri greater than pri pri. A pri of -1 indicates any priority is
804  * acceptable.
805  */
806 static inline int
807 sched_lowest(const struct cpu_group *cg, cpuset_t mask, int pri, int maxload,
808  int prefer)
809 {
810  struct cpu_search low;
811 
812  low.cs_cpu = -1;
813  low.cs_prefer = prefer;
814  low.cs_mask = mask;
815  low.cs_pri = pri;
816  low.cs_limit = maxload;
817  cpu_search_lowest(cg, &low);
818  return low.cs_cpu;
819 }
820 
821 /*
822  * Find the cpu with the highest load via the highest loaded path.
823  */
824 static inline int
825 sched_highest(const struct cpu_group *cg, cpuset_t mask, int minload)
826 {
827  struct cpu_search high;
828 
829  high.cs_cpu = -1;
830  high.cs_mask = mask;
831  high.cs_limit = minload;
832  cpu_search_highest(cg, &high);
833  return high.cs_cpu;
834 }
835 
836 static void
837 sched_balance_group(struct cpu_group *cg)
838 {
839  cpuset_t hmask, lmask;
840  int high, low, anylow;
841 
842  CPU_FILL(&hmask);
843  for (;;) {
844  high = sched_highest(cg, hmask, 1);
845  /* Stop if there is no more CPU with transferrable threads. */
846  if (high == -1)
847  break;
848  CPU_CLR(high, &hmask);
849  CPU_COPY(&hmask, &lmask);
850  /* Stop if there is no more CPU left for low. */
851  if (CPU_EMPTY(&lmask))
852  break;
853  anylow = 1;
854 nextlow:
855  low = sched_lowest(cg, lmask, -1,
856  TDQ_CPU(high)->tdq_load - 1, high);
857  /* Stop if we looked well and found no less loaded CPU. */
858  if (anylow && low == -1)
859  break;
860  /* Go to next high if we found no less loaded CPU. */
861  if (low == -1)
862  continue;
863  /* Transfer thread from high to low. */
864  if (sched_balance_pair(TDQ_CPU(high), TDQ_CPU(low))) {
865  /* CPU that got thread can no longer be a donor. */
866  CPU_CLR(low, &hmask);
867  } else {
868  /*
869  * If failed, then there is no threads on high
870  * that can run on this low. Drop low from low
871  * mask and look for different one.
872  */
873  CPU_CLR(low, &lmask);
874  anylow = 0;
875  goto nextlow;
876  }
877  }
878 }
879 
880 static void
881 sched_balance(void)
882 {
883  struct tdq *tdq;
884 
885  if (smp_started == 0 || rebalance == 0)
886  return;
887 
888  balance_ticks = max(balance_interval / 2, 1) +
889  (sched_random() % balance_interval);
890  tdq = TDQ_SELF();
891  TDQ_UNLOCK(tdq);
892  sched_balance_group(cpu_top);
893  TDQ_LOCK(tdq);
894 }
895 
896 /*
897  * Lock two thread queues using their address to maintain lock order.
898  */
899 static void
900 tdq_lock_pair(struct tdq *one, struct tdq *two)
901 {
902  if (one < two) {
903  TDQ_LOCK(one);
904  TDQ_LOCK_FLAGS(two, MTX_DUPOK);
905  } else {
906  TDQ_LOCK(two);
907  TDQ_LOCK_FLAGS(one, MTX_DUPOK);
908  }
909 }
910 
911 /*
912  * Unlock two thread queues. Order is not important here.
913  */
914 static void
915 tdq_unlock_pair(struct tdq *one, struct tdq *two)
916 {
917  TDQ_UNLOCK(one);
918  TDQ_UNLOCK(two);
919 }
920 
921 /*
922  * Transfer load between two imbalanced thread queues.
923  */
924 static int
925 sched_balance_pair(struct tdq *high, struct tdq *low)
926 {
927  int moved;
928  int cpu;
929 
930  tdq_lock_pair(high, low);
931  moved = 0;
932  /*
933  * Determine what the imbalance is and then adjust that to how many
934  * threads we actually have to give up (transferable).
935  */
936  if (high->tdq_transferable != 0 && high->tdq_load > low->tdq_load &&
937  (moved = tdq_move(high, low)) > 0) {
938  /*
939  * In case the target isn't the current cpu IPI it to force a
940  * reschedule with the new workload.
941  */
942  cpu = TDQ_ID(low);
943  if (cpu != PCPU_GET(cpuid))
944  ipi_cpu(cpu, IPI_PREEMPT);
945  }
946  tdq_unlock_pair(high, low);
947  return (moved);
948 }
949 
950 /*
951  * Move a thread from one thread queue to another.
952  */
953 static int
954 tdq_move(struct tdq *from, struct tdq *to)
955 {
956  struct td_sched *ts;
957  struct thread *td;
958  struct tdq *tdq;
959  int cpu;
960 
961  TDQ_LOCK_ASSERT(from, MA_OWNED);
962  TDQ_LOCK_ASSERT(to, MA_OWNED);
963 
964  tdq = from;
965  cpu = TDQ_ID(to);
966  td = tdq_steal(tdq, cpu);
967  if (td == NULL)
968  return (0);
969  ts = td_get_sched(td);
970  /*
971  * Although the run queue is locked the thread may be blocked. Lock
972  * it to clear this and acquire the run-queue lock.
973  */
974  thread_lock(td);
975  /* Drop recursive lock on from acquired via thread_lock(). */
976  TDQ_UNLOCK(from);
977  sched_rem(td);
978  ts->ts_cpu = cpu;
979  td->td_lock = TDQ_LOCKPTR(to);
980  tdq_add(to, td, SRQ_YIELDING);
981  return (1);
982 }
983 
984 /*
985  * This tdq has idled. Try to steal a thread from another cpu and switch
986  * to it.
987  */
988 static int
989 tdq_idled(struct tdq *tdq)
990 {
991  struct cpu_group *cg;
992  struct tdq *steal;
993  cpuset_t mask;
994  int thresh;
995  int cpu;
996 
997  if (smp_started == 0 || steal_idle == 0)
998  return (1);
999  CPU_FILL(&mask);
1000  CPU_CLR(PCPU_GET(cpuid), &mask);
1001  /* We don't want to be preempted while we're iterating. */
1002  spinlock_enter();
1003  for (cg = tdq->tdq_cg; cg != NULL; ) {
1004  if ((cg->cg_flags & CG_FLAG_THREAD) == 0)
1005  thresh = steal_thresh;
1006  else
1007  thresh = 1;
1008  cpu = sched_highest(cg, mask, thresh);
1009  if (cpu == -1) {
1010  cg = cg->cg_parent;
1011  continue;
1012  }
1013  steal = TDQ_CPU(cpu);
1014  CPU_CLR(cpu, &mask);
1015  tdq_lock_pair(tdq, steal);
1016  if (steal->tdq_load < thresh || steal->tdq_transferable == 0) {
1017  tdq_unlock_pair(tdq, steal);
1018  continue;
1019  }
1020  /*
1021  * If a thread was added while interrupts were disabled don't
1022  * steal one here. If we fail to acquire one due to affinity
1023  * restrictions loop again with this cpu removed from the
1024  * set.
1025  */
1026  if (tdq->tdq_load == 0 && tdq_move(steal, tdq) == 0) {
1027  tdq_unlock_pair(tdq, steal);
1028  continue;
1029  }
1030  spinlock_exit();
1031  TDQ_UNLOCK(steal);
1032  mi_switch(SW_VOL | SWT_IDLE, NULL);
1033  thread_unlock(curthread);
1034 
1035  return (0);
1036  }
1037  spinlock_exit();
1038  return (1);
1039 }
1040 
1041 /*
1042  * Notify a remote cpu of new work. Sends an IPI if criteria are met.
1043  */
1044 static void
1045 tdq_notify(struct tdq *tdq, struct thread *td)
1046 {
1047  struct thread *ctd;
1048  int pri;
1049  int cpu;
1050 
1051  if (tdq->tdq_ipipending)
1052  return;
1053  cpu = td_get_sched(td)->ts_cpu;
1054  pri = td->td_priority;
1055  ctd = pcpu_find(cpu)->pc_curthread;
1056  if (!sched_shouldpreempt(pri, ctd->td_priority, 1))
1057  return;
1058 
1059  /*
1060  * Make sure that our caller's earlier update to tdq_load is
1061  * globally visible before we read tdq_cpu_idle. Idle thread
1062  * accesses both of them without locks, and the order is important.
1063  */
1064  atomic_thread_fence_seq_cst();
1065 
1066  if (TD_IS_IDLETHREAD(ctd)) {
1067  /*
1068  * If the MD code has an idle wakeup routine try that before
1069  * falling back to IPI.
1070  */
1071  if (!tdq->tdq_cpu_idle || cpu_idle_wakeup(cpu))
1072  return;
1073  }
1074  tdq->tdq_ipipending = 1;
1075  ipi_cpu(cpu, IPI_PREEMPT);
1076 }
1077 
1078 /*
1079  * Steals load from a timeshare queue. Honors the rotating queue head
1080  * index.
1081  */
1082 static struct thread *
1083 runq_steal_from(struct runq *rq, int cpu, u_char start)
1084 {
1085  struct rqbits *rqb;
1086  struct rqhead *rqh;
1087  struct thread *td, *first;
1088  int bit;
1089  int i;
1090 
1091  rqb = &rq->rq_status;
1092  bit = start & (RQB_BPW -1);
1093  first = NULL;
1094 again:
1095  for (i = RQB_WORD(start); i < RQB_LEN; bit = 0, i++) {
1096  if (rqb->rqb_bits[i] == 0)
1097  continue;
1098  if (bit == 0)
1099  bit = RQB_FFS(rqb->rqb_bits[i]);
1100  for (; bit < RQB_BPW; bit++) {
1101  if ((rqb->rqb_bits[i] & (1ul << bit)) == 0)
1102  continue;
1103  rqh = &rq->rq_queues[bit + (i << RQB_L2BPW)];
1104  TAILQ_FOREACH(td, rqh, td_runq) {
1105  if (first && THREAD_CAN_MIGRATE(td) &&
1106  THREAD_CAN_SCHED(td, cpu))
1107  return (td);
1108  first = td;
1109  }
1110  }
1111  }
1112  if (start != 0) {
1113  start = 0;
1114  goto again;
1115  }
1116 
1117  if (first && THREAD_CAN_MIGRATE(first) &&
1118  THREAD_CAN_SCHED(first, cpu))
1119  return (first);
1120  return (NULL);
1121 }
1122 
1123 /*
1124  * Steals load from a standard linear queue.
1125  */
1126 static struct thread *
1127 runq_steal(struct runq *rq, int cpu)
1128 {
1129  struct rqhead *rqh;
1130  struct rqbits *rqb;
1131  struct thread *td;
1132  int word;
1133  int bit;
1134 
1135  rqb = &rq->rq_status;
1136  for (word = 0; word < RQB_LEN; word++) {
1137  if (rqb->rqb_bits[word] == 0)
1138  continue;
1139  for (bit = 0; bit < RQB_BPW; bit++) {
1140  if ((rqb->rqb_bits[word] & (1ul << bit)) == 0)
1141  continue;
1142  rqh = &rq->rq_queues[bit + (word << RQB_L2BPW)];
1143  TAILQ_FOREACH(td, rqh, td_runq)
1144  if (THREAD_CAN_MIGRATE(td) &&
1145  THREAD_CAN_SCHED(td, cpu))
1146  return (td);
1147  }
1148  }
1149  return (NULL);
1150 }
1151 
1152 /*
1153  * Attempt to steal a thread in priority order from a thread queue.
1154  */
1155 static struct thread *
1156 tdq_steal(struct tdq *tdq, int cpu)
1157 {
1158  struct thread *td;
1159 
1160  TDQ_LOCK_ASSERT(tdq, MA_OWNED);
1161  if ((td = runq_steal(&tdq->tdq_realtime, cpu)) != NULL)
1162  return (td);
1163  if ((td = runq_steal_from(&tdq->tdq_timeshare,
1164  cpu, tdq->tdq_ridx)) != NULL)
1165  return (td);
1166  return (runq_steal(&tdq->tdq_idle, cpu));
1167 }
1168 
1169 /*
1170  * Sets the thread lock and ts_cpu to match the requested cpu. Unlocks the
1171  * current lock and returns with the assigned queue locked.
1172  */
1173 static inline struct tdq *
1174 sched_setcpu(struct thread *td, int cpu, int flags)
1175 {
1176 
1177  struct tdq *tdq;
1178 
1179  THREAD_LOCK_ASSERT(td, MA_OWNED);
1180  tdq = TDQ_CPU(cpu);
1181  td_get_sched(td)->ts_cpu = cpu;
1182  /*
1183  * If the lock matches just return the queue.
1184  */
1185  if (td->td_lock == TDQ_LOCKPTR(tdq))
1186  return (tdq);
1187 #ifdef notyet
1188  /*
1189  * If the thread isn't running its lockptr is a
1190  * turnstile or a sleepqueue. We can just lock_set without
1191  * blocking.
1192  */
1193  if (TD_CAN_RUN(td)) {
1194  TDQ_LOCK(tdq);
1195  thread_lock_set(td, TDQ_LOCKPTR(tdq));
1196  return (tdq);
1197  }
1198 #endif
1199  /*
1200  * The hard case, migration, we need to block the thread first to
1201  * prevent order reversals with other cpus locks.
1202  */
1203  spinlock_enter();
1204  thread_lock_block(td);
1205  TDQ_LOCK(tdq);
1206  thread_lock_unblock(td, TDQ_LOCKPTR(tdq));
1207  spinlock_exit();
1208  return (tdq);
1209 }
1210 
1211 SCHED_STAT_DEFINE(pickcpu_intrbind, "Soft interrupt binding");
1212 SCHED_STAT_DEFINE(pickcpu_idle_affinity, "Picked idle cpu based on affinity");
1213 SCHED_STAT_DEFINE(pickcpu_affinity, "Picked cpu based on affinity");
1214 SCHED_STAT_DEFINE(pickcpu_lowest, "Selected lowest load");
1215 SCHED_STAT_DEFINE(pickcpu_local, "Migrated to current cpu");
1216 SCHED_STAT_DEFINE(pickcpu_migration, "Selection may have caused migration");
1217 
1218 static int
1219 sched_pickcpu(struct thread *td, int flags)
1220 {
1221  struct cpu_group *cg, *ccg;
1222  struct td_sched *ts;
1223  struct tdq *tdq;
1224  cpuset_t mask;
1225  int cpu, pri, self;
1226 
1227  self = PCPU_GET(cpuid);
1228  ts = td_get_sched(td);
1229  KASSERT(!CPU_ABSENT(ts->ts_cpu), ("sched_pickcpu: Start scheduler on "
1230  "absent CPU %d for thread %s.", ts->ts_cpu, td->td_name));
1231  if (smp_started == 0)
1232  return (self);
1233  /*
1234  * Don't migrate a running thread from sched_switch().
1235  */
1236  if ((flags & SRQ_OURSELF) || !THREAD_CAN_MIGRATE(td))
1237  return (ts->ts_cpu);
1238  /*
1239  * Prefer to run interrupt threads on the processors that generate
1240  * the interrupt.
1241  */
1242  pri = td->td_priority;
1243  if (td->td_priority <= PRI_MAX_ITHD && THREAD_CAN_SCHED(td, self) &&
1244  curthread->td_intr_nesting_level && ts->ts_cpu != self) {
1245  SCHED_STAT_INC(pickcpu_intrbind);
1246  ts->ts_cpu = self;
1247  if (TDQ_CPU(self)->tdq_lowpri > pri) {
1248  SCHED_STAT_INC(pickcpu_affinity);
1249  return (ts->ts_cpu);
1250  }
1251  }
1252  /*
1253  * If the thread can run on the last cpu and the affinity has not
1254  * expired or it is idle run it there.
1255  */
1256  tdq = TDQ_CPU(ts->ts_cpu);
1257  cg = tdq->tdq_cg;
1258  if (THREAD_CAN_SCHED(td, ts->ts_cpu) &&
1259  tdq->tdq_lowpri >= PRI_MIN_IDLE &&
1260  SCHED_AFFINITY(ts, CG_SHARE_L2)) {
1261  if (cg->cg_flags & CG_FLAG_THREAD) {
1262  CPUSET_FOREACH(cpu, cg->cg_mask) {
1263  if (TDQ_CPU(cpu)->tdq_lowpri < PRI_MIN_IDLE)
1264  break;
1265  }
1266  } else
1267  cpu = INT_MAX;
1268  if (cpu > mp_maxid) {
1269  SCHED_STAT_INC(pickcpu_idle_affinity);
1270  return (ts->ts_cpu);
1271  }
1272  }
1273  /*
1274  * Search for the last level cache CPU group in the tree.
1275  * Skip caches with expired affinity time and SMT groups.
1276  * Affinity to higher level caches will be handled less aggressively.
1277  */
1278  for (ccg = NULL; cg != NULL; cg = cg->cg_parent) {
1279  if (cg->cg_flags & CG_FLAG_THREAD)
1280  continue;
1281  if (!SCHED_AFFINITY(ts, cg->cg_level))
1282  continue;
1283  ccg = cg;
1284  }
1285  if (ccg != NULL)
1286  cg = ccg;
1287  cpu = -1;
1288  /* Search the group for the less loaded idle CPU we can run now. */
1289  mask = td->td_cpuset->cs_mask;
1290  if (cg != NULL && cg != cpu_top &&
1291  CPU_CMP(&cg->cg_mask, &cpu_top->cg_mask) != 0)
1292  cpu = sched_lowest(cg, mask, max(pri, PRI_MAX_TIMESHARE),
1293  INT_MAX, ts->ts_cpu);
1294  /* Search globally for the less loaded CPU we can run now. */
1295  if (cpu == -1)
1296  cpu = sched_lowest(cpu_top, mask, pri, INT_MAX, ts->ts_cpu);
1297  /* Search globally for the less loaded CPU. */
1298  if (cpu == -1)
1299  cpu = sched_lowest(cpu_top, mask, -1, INT_MAX, ts->ts_cpu);
1300  KASSERT(cpu != -1, ("sched_pickcpu: Failed to find a cpu."));
1301  KASSERT(!CPU_ABSENT(cpu), ("sched_pickcpu: Picked absent CPU %d.", cpu));
1302  /*
1303  * Compare the lowest loaded cpu to current cpu.
1304  */
1305  if (THREAD_CAN_SCHED(td, self) && TDQ_CPU(self)->tdq_lowpri > pri &&
1306  TDQ_CPU(cpu)->tdq_lowpri < PRI_MIN_IDLE &&
1307  TDQ_CPU(self)->tdq_load <= TDQ_CPU(cpu)->tdq_load + 1) {
1308  SCHED_STAT_INC(pickcpu_local);
1309  cpu = self;
1310  } else
1311  SCHED_STAT_INC(pickcpu_lowest);
1312  if (cpu != ts->ts_cpu)
1313  SCHED_STAT_INC(pickcpu_migration);
1314  return (cpu);
1315 }
1316 #endif
1317 
1318 /*
1319  * Pick the highest priority task we have and return it.
1320  */
1321 static struct thread *
1322 tdq_choose(struct tdq *tdq)
1323 {
1324  struct thread *td;
1325 
1326  TDQ_LOCK_ASSERT(tdq, MA_OWNED);
1327  td = runq_choose(&tdq->tdq_realtime);
1328  if (td != NULL)
1329  return (td);
1330  td = runq_choose_from(&tdq->tdq_timeshare, tdq->tdq_ridx);
1331  if (td != NULL) {
1332  KASSERT(td->td_priority >= PRI_MIN_BATCH,
1333  ("tdq_choose: Invalid priority on timeshare queue %d",
1334  td->td_priority));
1335  return (td);
1336  }
1337  td = runq_choose(&tdq->tdq_idle);
1338  if (td != NULL) {
1339  KASSERT(td->td_priority >= PRI_MIN_IDLE,
1340  ("tdq_choose: Invalid priority on idle queue %d",
1341  td->td_priority));
1342  return (td);
1343  }
1344 
1345  return (NULL);
1346 }
1347 
1348 /*
1349  * Initialize a thread queue.
1350  */
1351 static void
1352 tdq_setup(struct tdq *tdq)
1353 {
1354 
1355  if (bootverbose)
1356  printf("ULE: setup cpu %d\n", TDQ_ID(tdq));
1357  runq_init(&tdq->tdq_realtime);
1358  runq_init(&tdq->tdq_timeshare);
1359  runq_init(&tdq->tdq_idle);
1360  snprintf(tdq->tdq_name, sizeof(tdq->tdq_name),
1361  "sched lock %d", (int)TDQ_ID(tdq));
1362  mtx_init(&tdq->tdq_lock, tdq->tdq_name, "sched lock",
1363  MTX_SPIN | MTX_RECURSE);
1364 #ifdef KTR
1365  snprintf(tdq->tdq_loadname, sizeof(tdq->tdq_loadname),
1366  "CPU %d load", (int)TDQ_ID(tdq));
1367 #endif
1368 }
1369 
1370 #ifdef SMP
1371 static void
1372 sched_setup_smp(void)
1373 {
1374  struct tdq *tdq;
1375  int i;
1376 
1377  cpu_top = smp_topo();
1378  CPU_FOREACH(i) {
1379  tdq = TDQ_CPU(i);
1380  tdq_setup(tdq);
1381  tdq->tdq_cg = smp_topo_find(cpu_top, i);
1382  if (tdq->tdq_cg == NULL)
1383  panic("Can't find cpu group for %d\n", i);
1384  }
1385  balance_tdq = TDQ_SELF();
1386  sched_balance();
1387 }
1388 #endif
1389 
1390 /*
1391  * Setup the thread queues and initialize the topology based on MD
1392  * information.
1393  */
1394 static void
1396 {
1397  struct tdq *tdq;
1398 
1399  tdq = TDQ_SELF();
1400 #ifdef SMP
1401  sched_setup_smp();
1402 #else
1403  tdq_setup(tdq);
1404 #endif
1405 
1406  /* Add thread0's load since it's running. */
1407  TDQ_LOCK(tdq);
1408  thread0.td_lock = TDQ_LOCKPTR(TDQ_SELF());
1409  tdq_load_add(tdq, &thread0);
1410  tdq->tdq_lowpri = thread0.td_priority;
1411  TDQ_UNLOCK(tdq);
1412 }
1413 
1414 /*
1415  * This routine determines time constants after stathz and hz are setup.
1416  */
1417 /* ARGSUSED */
1418 static void
1420 {
1421  int incr;
1422 
1423  realstathz = stathz ? stathz : hz;
1424  sched_slice = realstathz / SCHED_SLICE_DEFAULT_DIVISOR;
1425  sched_slice_min = sched_slice / SCHED_SLICE_MIN_DIVISOR;
1426  hogticks = imax(1, (2 * hz * sched_slice + realstathz / 2) /
1427  realstathz);
1428 
1429  /*
1430  * tickincr is shifted out by 10 to avoid rounding errors due to
1431  * hz not being evenly divisible by stathz on all platforms.
1432  */
1433  incr = (hz << SCHED_TICK_SHIFT) / realstathz;
1434  /*
1435  * This does not work for values of stathz that are more than
1436  * 1 << SCHED_TICK_SHIFT * hz. In practice this does not happen.
1437  */
1438  if (incr == 0)
1439  incr = 1;
1440  tickincr = incr;
1441 #ifdef SMP
1442  /*
1443  * Set the default balance interval now that we know
1444  * what realstathz is.
1445  */
1446  balance_interval = realstathz;
1447  affinity = SCHED_AFFINITY_DEFAULT;
1448 #endif
1449  if (sched_idlespinthresh < 0)
1450  sched_idlespinthresh = 2 * max(10000, 6 * hz) / realstathz;
1451 }
1452 
1453 
1454 /*
1455  * This is the core of the interactivity algorithm. Determines a score based
1456  * on past behavior. It is the ratio of sleep time to run time scaled to
1457  * a [0, 100] integer. This is the voluntary sleep time of a process, which
1458  * differs from the cpu usage because it does not account for time spent
1459  * waiting on a run-queue. Would be prettier if we had floating point.
1460  *
1461  * When a thread's sleep time is greater than its run time the
1462  * calculation is:
1463  *
1464  * scaling factor
1465  * interactivity score = ---------------------
1466  * sleep time / run time
1467  *
1468  *
1469  * When a thread's run time is greater than its sleep time the
1470  * calculation is:
1471  *
1472  * scaling factor
1473  * interactivity score = --------------------- + scaling factor
1474  * run time / sleep time
1475  */
1476 static int
1477 sched_interact_score(struct thread *td)
1478 {
1479  struct td_sched *ts;
1480  int div;
1481 
1482  ts = td_get_sched(td);
1483  /*
1484  * The score is only needed if this is likely to be an interactive
1485  * task. Don't go through the expense of computing it if there's
1486  * no chance.
1487  */
1488  if (sched_interact <= SCHED_INTERACT_HALF &&
1489  ts->ts_runtime >= ts->ts_slptime)
1490  return (SCHED_INTERACT_HALF);
1491 
1492  if (ts->ts_runtime > ts->ts_slptime) {
1493  div = max(1, ts->ts_runtime / SCHED_INTERACT_HALF);
1494  return (SCHED_INTERACT_HALF +
1495  (SCHED_INTERACT_HALF - (ts->ts_slptime / div)));
1496  }
1497  if (ts->ts_slptime > ts->ts_runtime) {
1498  div = max(1, ts->ts_slptime / SCHED_INTERACT_HALF);
1499  return (ts->ts_runtime / div);
1500  }
1501  /* runtime == slptime */
1502  if (ts->ts_runtime)
1503  return (SCHED_INTERACT_HALF);
1504 
1505  /*
1506  * This can happen if slptime and runtime are 0.
1507  */
1508  return (0);
1509 
1510 }
1511 
1512 /*
1513  * Scale the scheduling priority according to the "interactivity" of this
1514  * process.
1515  */
1516 static void
1517 sched_priority(struct thread *td)
1518 {
1519  int score;
1520  int pri;
1521 
1522  if (PRI_BASE(td->td_pri_class) != PRI_TIMESHARE)
1523  return;
1524  /*
1525  * If the score is interactive we place the thread in the realtime
1526  * queue with a priority that is less than kernel and interrupt
1527  * priorities. These threads are not subject to nice restrictions.
1528  *
1529  * Scores greater than this are placed on the normal timeshare queue
1530  * where the priority is partially decided by the most recent cpu
1531  * utilization and the rest is decided by nice value.
1532  *
1533  * The nice value of the process has a linear effect on the calculated
1534  * score. Negative nice values make it easier for a thread to be
1535  * considered interactive.
1536  */
1537  score = imax(0, sched_interact_score(td) + td->td_proc->p_nice);
1538  if (score < sched_interact) {
1539  pri = PRI_MIN_INTERACT;
1540  pri += ((PRI_MAX_INTERACT - PRI_MIN_INTERACT + 1) /
1541  sched_interact) * score;
1542  KASSERT(pri >= PRI_MIN_INTERACT && pri <= PRI_MAX_INTERACT,
1543  ("sched_priority: invalid interactive priority %d score %d",
1544  pri, score));
1545  } else {
1546  pri = SCHED_PRI_MIN;
1547  if (td_get_sched(td)->ts_ticks)
1548  pri += min(SCHED_PRI_TICKS(td_get_sched(td)),
1549  SCHED_PRI_RANGE - 1);
1550  pri += SCHED_PRI_NICE(td->td_proc->p_nice);
1551  KASSERT(pri >= PRI_MIN_BATCH && pri <= PRI_MAX_BATCH,
1552  ("sched_priority: invalid priority %d: nice %d, "
1553  "ticks %d ftick %d ltick %d tick pri %d",
1554  pri, td->td_proc->p_nice, td_get_sched(td)->ts_ticks,
1555  td_get_sched(td)->ts_ftick, td_get_sched(td)->ts_ltick,
1556  SCHED_PRI_TICKS(td_get_sched(td))));
1557  }
1558  sched_user_prio(td, pri);
1559 
1560  return;
1561 }
1562 
1563 /*
1564  * This routine enforces a maximum limit on the amount of scheduling history
1565  * kept. It is called after either the slptime or runtime is adjusted. This
1566  * function is ugly due to integer math.
1567  */
1568 static void
1569 sched_interact_update(struct thread *td)
1570 {
1571  struct td_sched *ts;
1572  u_int sum;
1573 
1574  ts = td_get_sched(td);
1575  sum = ts->ts_runtime + ts->ts_slptime;
1576  if (sum < SCHED_SLP_RUN_MAX)
1577  return;
1578  /*
1579  * This only happens from two places:
1580  * 1) We have added an unusual amount of run time from fork_exit.
1581  * 2) We have added an unusual amount of sleep time from sched_sleep().
1582  */
1583  if (sum > SCHED_SLP_RUN_MAX * 2) {
1584  if (ts->ts_runtime > ts->ts_slptime) {
1586  ts->ts_slptime = 1;
1587  } else {
1589  ts->ts_runtime = 1;
1590  }
1591  return;
1592  }
1593  /*
1594  * If we have exceeded by more than 1/5th then the algorithm below
1595  * will not bring us back into range. Dividing by two here forces
1596  * us into the range of [4/5 * SCHED_INTERACT_MAX, SCHED_INTERACT_MAX]
1597  */
1598  if (sum > (SCHED_SLP_RUN_MAX / 5) * 6) {
1599  ts->ts_runtime /= 2;
1600  ts->ts_slptime /= 2;
1601  return;
1602  }
1603  ts->ts_runtime = (ts->ts_runtime / 5) * 4;
1604  ts->ts_slptime = (ts->ts_slptime / 5) * 4;
1605 }
1606 
1607 /*
1608  * Scale back the interactivity history when a child thread is created. The
1609  * history is inherited from the parent but the thread may behave totally
1610  * differently. For example, a shell spawning a compiler process. We want
1611  * to learn that the compiler is behaving badly very quickly.
1612  */
1613 static void
1614 sched_interact_fork(struct thread *td)
1615 {
1616  struct td_sched *ts;
1617  int ratio;
1618  int sum;
1619 
1620  ts = td_get_sched(td);
1621  sum = ts->ts_runtime + ts->ts_slptime;
1622  if (sum > SCHED_SLP_RUN_FORK) {
1623  ratio = sum / SCHED_SLP_RUN_FORK;
1624  ts->ts_runtime /= ratio;
1625  ts->ts_slptime /= ratio;
1626  }
1627 }
1628 
1629 /*
1630  * Called from proc0_init() to setup the scheduler fields.
1631  */
1632 void
1634 {
1635  struct td_sched *ts0;
1636 
1637  /*
1638  * Set up the scheduler specific parts of thread0.
1639  */
1640  ts0 = td_get_sched(&thread0);
1641  ts0->ts_ltick = ticks;
1642  ts0->ts_ftick = ticks;
1643  ts0->ts_slice = 0;
1644  ts0->ts_cpu = curcpu; /* set valid CPU number */
1645 }
1646 
1647 /*
1648  * This is only somewhat accurate since given many processes of the same
1649  * priority they will switch when their slices run out, which will be
1650  * at most sched_slice stathz ticks.
1651  */
1652 int
1654 {
1655 
1656  /* Convert sched_slice from stathz to hz. */
1657  return (imax(1, (sched_slice * hz + realstathz / 2) / realstathz));
1658 }
1659 
1660 /*
1661  * Update the percent cpu tracking information when it is requested or
1662  * the total history exceeds the maximum. We keep a sliding history of
1663  * tick counts that slowly decays. This is less precise than the 4BSD
1664  * mechanism since it happens with less regular and frequent events.
1665  */
1666 static void
1668 {
1669  int t = ticks;
1670 
1671  /*
1672  * The signed difference may be negative if the thread hasn't run for
1673  * over half of the ticks rollover period.
1674  */
1675  if ((u_int)(t - ts->ts_ltick) >= SCHED_TICK_TARG) {
1676  ts->ts_ticks = 0;
1677  ts->ts_ftick = t - SCHED_TICK_TARG;
1678  } else if (t - ts->ts_ftick >= SCHED_TICK_MAX) {
1679  ts->ts_ticks = (ts->ts_ticks / (ts->ts_ltick - ts->ts_ftick)) *
1680  (ts->ts_ltick - (t - SCHED_TICK_TARG));
1681  ts->ts_ftick = t - SCHED_TICK_TARG;
1682  }
1683  if (run)
1684  ts->ts_ticks += (t - ts->ts_ltick) << SCHED_TICK_SHIFT;
1685  ts->ts_ltick = t;
1686 }
1687 
1688 /*
1689  * Adjust the priority of a thread. Move it to the appropriate run-queue
1690  * if necessary. This is the back-end for several priority related
1691  * functions.
1692  */
1693 static void
1694 sched_thread_priority(struct thread *td, u_char prio)
1695 {
1696  struct td_sched *ts;
1697  struct tdq *tdq;
1698  int oldpri;
1699 
1700  KTR_POINT3(KTR_SCHED, "thread", sched_tdname(td), "prio",
1701  "prio:%d", td->td_priority, "new prio:%d", prio,
1702  KTR_ATTR_LINKED, sched_tdname(curthread));
1703  SDT_PROBE3(sched, , , change__pri, td, td->td_proc, prio);
1704  if (td != curthread && prio < td->td_priority) {
1705  KTR_POINT3(KTR_SCHED, "thread", sched_tdname(curthread),
1706  "lend prio", "prio:%d", td->td_priority, "new prio:%d",
1707  prio, KTR_ATTR_LINKED, sched_tdname(td));
1708  SDT_PROBE4(sched, , , lend__pri, td, td->td_proc, prio,
1709  curthread);
1710  }
1711  ts = td_get_sched(td);
1712  THREAD_LOCK_ASSERT(td, MA_OWNED);
1713  if (td->td_priority == prio)
1714  return;
1715  /*
1716  * If the priority has been elevated due to priority
1717  * propagation, we may have to move ourselves to a new
1718  * queue. This could be optimized to not re-add in some
1719  * cases.
1720  */
1721  if (TD_ON_RUNQ(td) && prio < td->td_priority) {
1722  sched_rem(td);
1723  td->td_priority = prio;
1724  sched_add(td, SRQ_BORROWING);
1725  return;
1726  }
1727  /*
1728  * If the thread is currently running we may have to adjust the lowpri
1729  * information so other cpus are aware of our current priority.
1730  */
1731  if (TD_IS_RUNNING(td)) {
1732  tdq = TDQ_CPU(ts->ts_cpu);
1733  oldpri = td->td_priority;
1734  td->td_priority = prio;
1735  if (prio < tdq->tdq_lowpri)
1736  tdq->tdq_lowpri = prio;
1737  else if (tdq->tdq_lowpri == oldpri)
1738  tdq_setlowpri(tdq, td);
1739  return;
1740  }
1741  td->td_priority = prio;
1742 }
1743 
1744 /*
1745  * Update a thread's priority when it is lent another thread's
1746  * priority.
1747  */
1748 void
1749 sched_lend_prio(struct thread *td, u_char prio)
1750 {
1751 
1752  td->td_flags |= TDF_BORROWING;
1753  sched_thread_priority(td, prio);
1754 }
1755 
1756 /*
1757  * Restore a thread's priority when priority propagation is
1758  * over. The prio argument is the minimum priority the thread
1759  * needs to have to satisfy other possible priority lending
1760  * requests. If the thread's regular priority is less
1761  * important than prio, the thread will keep a priority boost
1762  * of prio.
1763  */
1764 void
1765 sched_unlend_prio(struct thread *td, u_char prio)
1766 {
1767  u_char base_pri;
1768 
1769  if (td->td_base_pri >= PRI_MIN_TIMESHARE &&
1770  td->td_base_pri <= PRI_MAX_TIMESHARE)
1771  base_pri = td->td_user_pri;
1772  else
1773  base_pri = td->td_base_pri;
1774  if (prio >= base_pri) {
1775  td->td_flags &= ~TDF_BORROWING;
1776  sched_thread_priority(td, base_pri);
1777  } else
1778  sched_lend_prio(td, prio);
1779 }
1780 
1781 /*
1782  * Standard entry for setting the priority to an absolute value.
1783  */
1784 void
1785 sched_prio(struct thread *td, u_char prio)
1786 {
1787  u_char oldprio;
1788 
1789  /* First, update the base priority. */
1790  td->td_base_pri = prio;
1791 
1792  /*
1793  * If the thread is borrowing another thread's priority, don't
1794  * ever lower the priority.
1795  */
1796  if (td->td_flags & TDF_BORROWING && td->td_priority < prio)
1797  return;
1798 
1799  /* Change the real priority. */
1800  oldprio = td->td_priority;
1801  sched_thread_priority(td, prio);
1802 
1803  /*
1804  * If the thread is on a turnstile, then let the turnstile update
1805  * its state.
1806  */
1807  if (TD_ON_LOCK(td) && oldprio != prio)
1808  turnstile_adjust(td, oldprio);
1809 }
1810 
1811 /*
1812  * Set the base user priority, does not effect current running priority.
1813  */
1814 void
1815 sched_user_prio(struct thread *td, u_char prio)
1816 {
1817 
1818  td->td_base_user_pri = prio;
1819  if (td->td_lend_user_pri <= prio)
1820  return;
1821  td->td_user_pri = prio;
1822 }
1823 
1824 void
1825 sched_lend_user_prio(struct thread *td, u_char prio)
1826 {
1827 
1828  THREAD_LOCK_ASSERT(td, MA_OWNED);
1829  td->td_lend_user_pri = prio;
1830  td->td_user_pri = min(prio, td->td_base_user_pri);
1831  if (td->td_priority > td->td_user_pri)
1832  sched_prio(td, td->td_user_pri);
1833  else if (td->td_priority != td->td_user_pri)
1834  td->td_flags |= TDF_NEEDRESCHED;
1835 }
1836 
1837 /*
1838  * Handle migration from sched_switch(). This happens only for
1839  * cpu binding.
1840  */
1841 static struct mtx *
1842 sched_switch_migrate(struct tdq *tdq, struct thread *td, int flags)
1843 {
1844  struct tdq *tdn;
1845 
1846  KASSERT(!CPU_ABSENT(td_get_sched(td)->ts_cpu), ("sched_switch_migrate: "
1847  "thread %s queued on absent CPU %d.", td->td_name,
1848  td_get_sched(td)->ts_cpu));
1849  tdn = TDQ_CPU(td_get_sched(td)->ts_cpu);
1850 #ifdef SMP
1851  tdq_load_rem(tdq, td);
1852  /*
1853  * Do the lock dance required to avoid LOR. We grab an extra
1854  * spinlock nesting to prevent preemption while we're
1855  * not holding either run-queue lock.
1856  */
1857  spinlock_enter();
1858  thread_lock_block(td); /* This releases the lock on tdq. */
1859 
1860  /*
1861  * Acquire both run-queue locks before placing the thread on the new
1862  * run-queue to avoid deadlocks created by placing a thread with a
1863  * blocked lock on the run-queue of a remote processor. The deadlock
1864  * occurs when a third processor attempts to lock the two queues in
1865  * question while the target processor is spinning with its own
1866  * run-queue lock held while waiting for the blocked lock to clear.
1867  */
1868  tdq_lock_pair(tdn, tdq);
1869  tdq_add(tdn, td, flags);
1870  tdq_notify(tdn, td);
1871  TDQ_UNLOCK(tdn);
1872  spinlock_exit();
1873 #endif
1874  return (TDQ_LOCKPTR(tdn));
1875 }
1876 
1877 /*
1878  * Variadic version of thread_lock_unblock() that does not assume td_lock
1879  * is blocked.
1880  */
1881 static inline void
1882 thread_unblock_switch(struct thread *td, struct mtx *mtx)
1883 {
1884  atomic_store_rel_ptr((volatile uintptr_t *)&td->td_lock,
1885  (uintptr_t)mtx);
1886 }
1887 
1888 /*
1889  * Switch threads. This function has to handle threads coming in while
1890  * blocked for some reason, running, or idle. It also must deal with
1891  * migrating a thread from one queue to another as running threads may
1892  * be assigned elsewhere via binding.
1893  */
1894 void
1895 sched_switch(struct thread *td, struct thread *newtd, int flags)
1896 {
1897  struct tdq *tdq;
1898  struct td_sched *ts;
1899  struct mtx *mtx;
1900  int srqflag;
1901  int cpuid, preempted;
1902 
1903  THREAD_LOCK_ASSERT(td, MA_OWNED);
1904  KASSERT(newtd == NULL, ("sched_switch: Unsupported newtd argument"));
1905 
1906  cpuid = PCPU_GET(cpuid);
1907  tdq = TDQ_CPU(cpuid);
1908  ts = td_get_sched(td);
1909  mtx = td->td_lock;
1910  sched_pctcpu_update(ts, 1);
1911  ts->ts_rltick = ticks;
1912  td->td_lastcpu = td->td_oncpu;
1913  td->td_oncpu = NOCPU;
1914  preempted = (td->td_flags & TDF_SLICEEND) == 0 &&
1915  (flags & SW_PREEMPT) != 0;
1916  td->td_flags &= ~(TDF_NEEDRESCHED | TDF_SLICEEND);
1917  td->td_owepreempt = 0;
1918  if (!TD_IS_IDLETHREAD(td))
1919  tdq->tdq_switchcnt++;
1920  /*
1921  * The lock pointer in an idle thread should never change. Reset it
1922  * to CAN_RUN as well.
1923  */
1924  if (TD_IS_IDLETHREAD(td)) {
1925  MPASS(td->td_lock == TDQ_LOCKPTR(tdq));
1926  TD_SET_CAN_RUN(td);
1927  } else if (TD_IS_RUNNING(td)) {
1928  MPASS(td->td_lock == TDQ_LOCKPTR(tdq));
1929  srqflag = preempted ?
1930  SRQ_OURSELF|SRQ_YIELDING|SRQ_PREEMPTED :
1931  SRQ_OURSELF|SRQ_YIELDING;
1932 #ifdef SMP
1933  if (THREAD_CAN_MIGRATE(td) && !THREAD_CAN_SCHED(td, ts->ts_cpu))
1934  ts->ts_cpu = sched_pickcpu(td, 0);
1935 #endif
1936  if (ts->ts_cpu == cpuid)
1937  tdq_runq_add(tdq, td, srqflag);
1938  else {
1939  KASSERT(THREAD_CAN_MIGRATE(td) ||
1940  (ts->ts_flags & TSF_BOUND) != 0,
1941  ("Thread %p shouldn't migrate", td));
1942  mtx = sched_switch_migrate(tdq, td, srqflag);
1943  }
1944  } else {
1945  /* This thread must be going to sleep. */
1946  TDQ_LOCK(tdq);
1947  mtx = thread_lock_block(td);
1948  tdq_load_rem(tdq, td);
1949  }
1950 
1951 #if (KTR_COMPILE & KTR_SCHED) != 0
1952  if (TD_IS_IDLETHREAD(td))
1953  KTR_STATE1(KTR_SCHED, "thread", sched_tdname(td), "idle",
1954  "prio:%d", td->td_priority);
1955  else
1956  KTR_STATE3(KTR_SCHED, "thread", sched_tdname(td), KTDSTATE(td),
1957  "prio:%d", td->td_priority, "wmesg:\"%s\"", td->td_wmesg,
1958  "lockname:\"%s\"", td->td_lockname);
1959 #endif
1960 
1961  /*
1962  * We enter here with the thread blocked and assigned to the
1963  * appropriate cpu run-queue or sleep-queue and with the current
1964  * thread-queue locked.
1965  */
1966  TDQ_LOCK_ASSERT(tdq, MA_OWNED | MA_NOTRECURSED);
1967  newtd = choosethread();
1968  /*
1969  * Call the MD code to switch contexts if necessary.
1970  */
1971  if (td != newtd) {
1972 #ifdef HWPMC_HOOKS
1973  if (PMC_PROC_IS_USING_PMCS(td->td_proc))
1974  PMC_SWITCH_CONTEXT(td, PMC_FN_CSW_OUT);
1975 #endif
1976  SDT_PROBE2(sched, , , off__cpu, newtd, newtd->td_proc);
1977  lock_profile_release_lock(&TDQ_LOCKPTR(tdq)->lock_object);
1978  TDQ_LOCKPTR(tdq)->mtx_lock = (uintptr_t)newtd;
1979  sched_pctcpu_update(td_get_sched(newtd), 0);
1980 
1981 #ifdef KDTRACE_HOOKS
1982  /*
1983  * If DTrace has set the active vtime enum to anything
1984  * other than INACTIVE (0), then it should have set the
1985  * function to call.
1986  */
1987  if (dtrace_vtime_active)
1988  (*dtrace_vtime_switch_func)(newtd);
1989 #endif
1990 
1991  cpu_switch(td, newtd, mtx);
1992  /*
1993  * We may return from cpu_switch on a different cpu. However,
1994  * we always return with td_lock pointing to the current cpu's
1995  * run queue lock.
1996  */
1997  cpuid = PCPU_GET(cpuid);
1998  tdq = TDQ_CPU(cpuid);
1999  lock_profile_obtain_lock_success(
2000  &TDQ_LOCKPTR(tdq)->lock_object, 0, 0, __FILE__, __LINE__);
2001 
2002  SDT_PROBE0(sched, , , on__cpu);
2003 #ifdef HWPMC_HOOKS
2004  if (PMC_PROC_IS_USING_PMCS(td->td_proc))
2005  PMC_SWITCH_CONTEXT(td, PMC_FN_CSW_IN);
2006 #endif
2007  } else {
2008  thread_unblock_switch(td, mtx);
2009  SDT_PROBE0(sched, , , remain__cpu);
2010  }
2011 
2012  KTR_STATE1(KTR_SCHED, "thread", sched_tdname(td), "running",
2013  "prio:%d", td->td_priority);
2014 
2015  /*
2016  * Assert that all went well and return.
2017  */
2018  TDQ_LOCK_ASSERT(tdq, MA_OWNED|MA_NOTRECURSED);
2019  MPASS(td->td_lock == TDQ_LOCKPTR(tdq));
2020  td->td_oncpu = cpuid;
2021 }
2022 
2023 /*
2024  * Adjust thread priorities as a result of a nice request.
2025  */
2026 void
2027 sched_nice(struct proc *p, int nice)
2028 {
2029  struct thread *td;
2030 
2031  PROC_LOCK_ASSERT(p, MA_OWNED);
2032 
2033  p->p_nice = nice;
2034  FOREACH_THREAD_IN_PROC(p, td) {
2035  thread_lock(td);
2036  sched_priority(td);
2037  sched_prio(td, td->td_base_user_pri);
2038  thread_unlock(td);
2039  }
2040 }
2041 
2042 /*
2043  * Record the sleep time for the interactivity scorer.
2044  */
2045 void
2046 sched_sleep(struct thread *td, int prio)
2047 {
2048 
2049  THREAD_LOCK_ASSERT(td, MA_OWNED);
2050 
2051  td->td_slptick = ticks;
2052  if (TD_IS_SUSPENDED(td) || prio >= PSOCK)
2053  td->td_flags |= TDF_CANSWAP;
2054  if (PRI_BASE(td->td_pri_class) != PRI_TIMESHARE)
2055  return;
2056  if (static_boost == 1 && prio)
2057  sched_prio(td, prio);
2058  else if (static_boost && td->td_priority > static_boost)
2059  sched_prio(td, static_boost);
2060 }
2061 
2062 /*
2063  * Schedule a thread to resume execution and record how long it voluntarily
2064  * slept. We also update the pctcpu, interactivity, and priority.
2065  */
2066 void
2067 sched_wakeup(struct thread *td)
2068 {
2069  struct td_sched *ts;
2070  int slptick;
2071 
2072  THREAD_LOCK_ASSERT(td, MA_OWNED);
2073  ts = td_get_sched(td);
2074  td->td_flags &= ~TDF_CANSWAP;
2075  /*
2076  * If we slept for more than a tick update our interactivity and
2077  * priority.
2078  */
2079  slptick = td->td_slptick;
2080  td->td_slptick = 0;
2081  if (slptick && slptick != ticks) {
2082  ts->ts_slptime += (ticks - slptick) << SCHED_TICK_SHIFT;
2084  sched_pctcpu_update(ts, 0);
2085  }
2086  /*
2087  * Reset the slice value since we slept and advanced the round-robin.
2088  */
2089  ts->ts_slice = 0;
2090  sched_add(td, SRQ_BORING);
2091 }
2092 
2093 /*
2094  * Penalize the parent for creating a new child and initialize the child's
2095  * priority.
2096  */
2097 void
2098 sched_fork(struct thread *td, struct thread *child)
2099 {
2100  THREAD_LOCK_ASSERT(td, MA_OWNED);
2101  sched_pctcpu_update(td_get_sched(td), 1);
2102  sched_fork_thread(td, child);
2103  /*
2104  * Penalize the parent and child for forking.
2105  */
2106  sched_interact_fork(child);
2107  sched_priority(child);
2108  td_get_sched(td)->ts_runtime += tickincr;
2110  sched_priority(td);
2111 }
2112 
2113 /*
2114  * Fork a new thread, may be within the same process.
2115  */
2116 void
2117 sched_fork_thread(struct thread *td, struct thread *child)
2118 {
2119  struct td_sched *ts;
2120  struct td_sched *ts2;
2121  struct tdq *tdq;
2122 
2123  tdq = TDQ_SELF();
2124  THREAD_LOCK_ASSERT(td, MA_OWNED);
2125  /*
2126  * Initialize child.
2127  */
2128  ts = td_get_sched(td);
2129  ts2 = td_get_sched(child);
2130  child->td_oncpu = NOCPU;
2131  child->td_lastcpu = NOCPU;
2132  child->td_lock = TDQ_LOCKPTR(tdq);
2133  child->td_cpuset = cpuset_ref(td->td_cpuset);
2134  child->td_domain.dr_policy = td->td_cpuset->cs_domain;
2135  ts2->ts_cpu = ts->ts_cpu;
2136  ts2->ts_flags = 0;
2137  /*
2138  * Grab our parents cpu estimation information.
2139  */
2140  ts2->ts_ticks = ts->ts_ticks;
2141  ts2->ts_ltick = ts->ts_ltick;
2142  ts2->ts_ftick = ts->ts_ftick;
2143  /*
2144  * Do not inherit any borrowed priority from the parent.
2145  */
2146  child->td_priority = child->td_base_pri;
2147  /*
2148  * And update interactivity score.
2149  */
2150  ts2->ts_slptime = ts->ts_slptime;
2151  ts2->ts_runtime = ts->ts_runtime;
2152  /* Attempt to quickly learn interactivity. */
2153  ts2->ts_slice = tdq_slice(tdq) - sched_slice_min;
2154 #ifdef KTR
2155  bzero(ts2->ts_name, sizeof(ts2->ts_name));
2156 #endif
2157 }
2158 
2159 /*
2160  * Adjust the priority class of a thread.
2161  */
2162 void
2163 sched_class(struct thread *td, int class)
2164 {
2165 
2166  THREAD_LOCK_ASSERT(td, MA_OWNED);
2167  if (td->td_pri_class == class)
2168  return;
2169  td->td_pri_class = class;
2170 }
2171 
2172 /*
2173  * Return some of the child's priority and interactivity to the parent.
2174  */
2175 void
2176 sched_exit(struct proc *p, struct thread *child)
2177 {
2178  struct thread *td;
2179 
2180  KTR_STATE1(KTR_SCHED, "thread", sched_tdname(child), "proc exit",
2181  "prio:%d", child->td_priority);
2182  PROC_LOCK_ASSERT(p, MA_OWNED);
2183  td = FIRST_THREAD_IN_PROC(p);
2184  sched_exit_thread(td, child);
2185 }
2186 
2187 /*
2188  * Penalize another thread for the time spent on this one. This helps to
2189  * worsen the priority and interactivity of processes which schedule batch
2190  * jobs such as make. This has little effect on the make process itself but
2191  * causes new processes spawned by it to receive worse scores immediately.
2192  */
2193 void
2194 sched_exit_thread(struct thread *td, struct thread *child)
2195 {
2196 
2197  KTR_STATE1(KTR_SCHED, "thread", sched_tdname(child), "thread exit",
2198  "prio:%d", child->td_priority);
2199  /*
2200  * Give the child's runtime to the parent without returning the
2201  * sleep time as a penalty to the parent. This causes shells that
2202  * launch expensive things to mark their children as expensive.
2203  */
2204  thread_lock(td);
2205  td_get_sched(td)->ts_runtime += td_get_sched(child)->ts_runtime;
2207  sched_priority(td);
2208  thread_unlock(td);
2209 }
2210 
2211 void
2212 sched_preempt(struct thread *td)
2213 {
2214  struct tdq *tdq;
2215 
2216  SDT_PROBE2(sched, , , surrender, td, td->td_proc);
2217 
2218  thread_lock(td);
2219  tdq = TDQ_SELF();
2220  TDQ_LOCK_ASSERT(tdq, MA_OWNED);
2221  tdq->tdq_ipipending = 0;
2222  if (td->td_priority > tdq->tdq_lowpri) {
2223  int flags;
2224 
2225  flags = SW_INVOL | SW_PREEMPT;
2226  if (td->td_critnest > 1)
2227  td->td_owepreempt = 1;
2228  else if (TD_IS_IDLETHREAD(td))
2229  mi_switch(flags | SWT_REMOTEWAKEIDLE, NULL);
2230  else
2231  mi_switch(flags | SWT_REMOTEPREEMPT, NULL);
2232  }
2233  thread_unlock(td);
2234 }
2235 
2236 /*
2237  * Fix priorities on return to user-space. Priorities may be elevated due
2238  * to static priorities in msleep() or similar.
2239  */
2240 void
2241 sched_userret(struct thread *td)
2242 {
2243  /*
2244  * XXX we cheat slightly on the locking here to avoid locking in
2245  * the usual case. Setting td_priority here is essentially an
2246  * incomplete workaround for not setting it properly elsewhere.
2247  * Now that some interrupt handlers are threads, not setting it
2248  * properly elsewhere can clobber it in the window between setting
2249  * it here and returning to user mode, so don't waste time setting
2250  * it perfectly here.
2251  */
2252  KASSERT((td->td_flags & TDF_BORROWING) == 0,
2253  ("thread with borrowed priority returning to userland"));
2254  if (td->td_priority != td->td_user_pri) {
2255  thread_lock(td);
2256  td->td_priority = td->td_user_pri;
2257  td->td_base_pri = td->td_user_pri;
2258  tdq_setlowpri(TDQ_SELF(), td);
2259  thread_unlock(td);
2260  }
2261 }
2262 
2263 /*
2264  * Handle a stathz tick. This is really only relevant for timeshare
2265  * threads.
2266  */
2267 void
2268 sched_clock(struct thread *td)
2269 {
2270  struct tdq *tdq;
2271  struct td_sched *ts;
2272 
2273  THREAD_LOCK_ASSERT(td, MA_OWNED);
2274  tdq = TDQ_SELF();
2275 #ifdef SMP
2276  /*
2277  * We run the long term load balancer infrequently on the first cpu.
2278  */
2279  if (balance_tdq == tdq) {
2280  if (balance_ticks && --balance_ticks == 0)
2281  sched_balance();
2282  }
2283 #endif
2284  /*
2285  * Save the old switch count so we have a record of the last ticks
2286  * activity. Initialize the new switch count based on our load.
2287  * If there is some activity seed it to reflect that.
2288  */
2289  tdq->tdq_oldswitchcnt = tdq->tdq_switchcnt;
2290  tdq->tdq_switchcnt = tdq->tdq_load;
2291  /*
2292  * Advance the insert index once for each tick to ensure that all
2293  * threads get a chance to run.
2294  */
2295  if (tdq->tdq_idx == tdq->tdq_ridx) {
2296  tdq->tdq_idx = (tdq->tdq_idx + 1) % RQ_NQS;
2297  if (TAILQ_EMPTY(&tdq->tdq_timeshare.rq_queues[tdq->tdq_ridx]))
2298  tdq->tdq_ridx = tdq->tdq_idx;
2299  }
2300  ts = td_get_sched(td);
2301  sched_pctcpu_update(ts, 1);
2302  if (td->td_pri_class & PRI_FIFO_BIT)
2303  return;
2304  if (PRI_BASE(td->td_pri_class) == PRI_TIMESHARE) {
2305  /*
2306  * We used a tick; charge it to the thread so
2307  * that we can compute our interactivity.
2308  */
2309  td_get_sched(td)->ts_runtime += tickincr;
2311  sched_priority(td);
2312  }
2313 
2314  /*
2315  * Force a context switch if the current thread has used up a full
2316  * time slice (default is 100ms).
2317  */
2318  if (!TD_IS_IDLETHREAD(td) && ++ts->ts_slice >= tdq_slice(tdq)) {
2319  ts->ts_slice = 0;
2320  td->td_flags |= TDF_NEEDRESCHED | TDF_SLICEEND;
2321  }
2322 }
2323 
2324 u_int
2325 sched_estcpu(struct thread *td __unused)
2326 {
2327 
2328  return (0);
2329 }
2330 
2331 /*
2332  * Return whether the current CPU has runnable tasks. Used for in-kernel
2333  * cooperative idle threads.
2334  */
2335 int
2337 {
2338  struct tdq *tdq;
2339  int load;
2340 
2341  load = 1;
2342 
2343  tdq = TDQ_SELF();
2344  if ((curthread->td_flags & TDF_IDLETD) != 0) {
2345  if (tdq->tdq_load > 0)
2346  goto out;
2347  } else
2348  if (tdq->tdq_load - 1 > 0)
2349  goto out;
2350  load = 0;
2351 out:
2352  return (load);
2353 }
2354 
2355 /*
2356  * Choose the highest priority thread to run. The thread is removed from
2357  * the run-queue while running however the load remains. For SMP we set
2358  * the tdq in the global idle bitmask if it idles here.
2359  */
2360 struct thread *
2362 {
2363  struct thread *td;
2364  struct tdq *tdq;
2365 
2366  tdq = TDQ_SELF();
2367  TDQ_LOCK_ASSERT(tdq, MA_OWNED);
2368  td = tdq_choose(tdq);
2369  if (td) {
2370  tdq_runq_rem(tdq, td);
2371  tdq->tdq_lowpri = td->td_priority;
2372  return (td);
2373  }
2374  tdq->tdq_lowpri = PRI_MAX_IDLE;
2375  return (PCPU_GET(idlethread));
2376 }
2377 
2378 /*
2379  * Set owepreempt if necessary. Preemption never happens directly in ULE,
2380  * we always request it once we exit a critical section.
2381  */
2382 static inline void
2383 sched_setpreempt(struct thread *td)
2384 {
2385  struct thread *ctd;
2386  int cpri;
2387  int pri;
2388 
2389  THREAD_LOCK_ASSERT(curthread, MA_OWNED);
2390 
2391  ctd = curthread;
2392  pri = td->td_priority;
2393  cpri = ctd->td_priority;
2394  if (pri < cpri)
2395  ctd->td_flags |= TDF_NEEDRESCHED;
2396  if (panicstr != NULL || pri >= cpri || cold || TD_IS_INHIBITED(ctd))
2397  return;
2398  if (!sched_shouldpreempt(pri, cpri, 0))
2399  return;
2400  ctd->td_owepreempt = 1;
2401 }
2402 
2403 /*
2404  * Add a thread to a thread queue. Select the appropriate runq and add the
2405  * thread to it. This is the internal function called when the tdq is
2406  * predetermined.
2407  */
2408 void
2409 tdq_add(struct tdq *tdq, struct thread *td, int flags)
2410 {
2411 
2412  TDQ_LOCK_ASSERT(tdq, MA_OWNED);
2413  KASSERT((td->td_inhibitors == 0),
2414  ("sched_add: trying to run inhibited thread"));
2415  KASSERT((TD_CAN_RUN(td) || TD_IS_RUNNING(td)),
2416  ("sched_add: bad thread state"));
2417  KASSERT(td->td_flags & TDF_INMEM,
2418  ("sched_add: thread swapped out"));
2419 
2420  if (td->td_priority < tdq->tdq_lowpri)
2421  tdq->tdq_lowpri = td->td_priority;
2422  tdq_runq_add(tdq, td, flags);
2423  tdq_load_add(tdq, td);
2424 }
2425 
2426 /*
2427  * Select the target thread queue and add a thread to it. Request
2428  * preemption or IPI a remote processor if required.
2429  */
2430 void
2431 sched_add(struct thread *td, int flags)
2432 {
2433  struct tdq *tdq;
2434 #ifdef SMP
2435  int cpu;
2436 #endif
2437 
2438  KTR_STATE2(KTR_SCHED, "thread", sched_tdname(td), "runq add",
2439  "prio:%d", td->td_priority, KTR_ATTR_LINKED,
2440  sched_tdname(curthread));
2441  KTR_POINT1(KTR_SCHED, "thread", sched_tdname(curthread), "wokeup",
2442  KTR_ATTR_LINKED, sched_tdname(td));
2443  SDT_PROBE4(sched, , , enqueue, td, td->td_proc, NULL,
2444  flags & SRQ_PREEMPTED);
2445  THREAD_LOCK_ASSERT(td, MA_OWNED);
2446  /*
2447  * Recalculate the priority before we select the target cpu or
2448  * run-queue.
2449  */
2450  if (PRI_BASE(td->td_pri_class) == PRI_TIMESHARE)
2451  sched_priority(td);
2452 #ifdef SMP
2453  /*
2454  * Pick the destination cpu and if it isn't ours transfer to the
2455  * target cpu.
2456  */
2457  cpu = sched_pickcpu(td, flags);
2458  tdq = sched_setcpu(td, cpu, flags);
2459  tdq_add(tdq, td, flags);
2460  if (cpu != PCPU_GET(cpuid)) {
2461  tdq_notify(tdq, td);
2462  return;
2463  }
2464 #else
2465  tdq = TDQ_SELF();
2466  TDQ_LOCK(tdq);
2467  /*
2468  * Now that the thread is moving to the run-queue, set the lock
2469  * to the scheduler's lock.
2470  */
2471  thread_lock_set(td, TDQ_LOCKPTR(tdq));
2472  tdq_add(tdq, td, flags);
2473 #endif
2474  if (!(flags & SRQ_YIELDING))
2475  sched_setpreempt(td);
2476 }
2477 
2478 /*
2479  * Remove a thread from a run-queue without running it. This is used
2480  * when we're stealing a thread from a remote queue. Otherwise all threads
2481  * exit by calling sched_exit_thread() and sched_throw() themselves.
2482  */
2483 void
2484 sched_rem(struct thread *td)
2485 {
2486  struct tdq *tdq;
2487 
2488  KTR_STATE1(KTR_SCHED, "thread", sched_tdname(td), "runq rem",
2489  "prio:%d", td->td_priority);
2490  SDT_PROBE3(sched, , , dequeue, td, td->td_proc, NULL);
2491  tdq = TDQ_CPU(td_get_sched(td)->ts_cpu);
2492  TDQ_LOCK_ASSERT(tdq, MA_OWNED);
2493  MPASS(td->td_lock == TDQ_LOCKPTR(tdq));
2494  KASSERT(TD_ON_RUNQ(td),
2495  ("sched_rem: thread not on run queue"));
2496  tdq_runq_rem(tdq, td);
2497  tdq_load_rem(tdq, td);
2498  TD_SET_CAN_RUN(td);
2499  if (td->td_priority == tdq->tdq_lowpri)
2500  tdq_setlowpri(tdq, NULL);
2501 }
2502 
2503 /*
2504  * Fetch cpu utilization information. Updates on demand.
2505  */
2506 fixpt_t
2507 sched_pctcpu(struct thread *td)
2508 {
2509  fixpt_t pctcpu;
2510  struct td_sched *ts;
2511 
2512  pctcpu = 0;
2513  ts = td_get_sched(td);
2514 
2515  THREAD_LOCK_ASSERT(td, MA_OWNED);
2516  sched_pctcpu_update(ts, TD_IS_RUNNING(td));
2517  if (ts->ts_ticks) {
2518  int rtick;
2519 
2520  /* How many rtick per second ? */
2521  rtick = min(SCHED_TICK_HZ(ts) / SCHED_TICK_SECS, hz);
2522  pctcpu = (FSCALE * ((FSCALE * rtick)/hz)) >> FSHIFT;
2523  }
2524 
2525  return (pctcpu);
2526 }
2527 
2528 /*
2529  * Enforce affinity settings for a thread. Called after adjustments to
2530  * cpumask.
2531  */
2532 void
2533 sched_affinity(struct thread *td)
2534 {
2535 #ifdef SMP
2536  struct td_sched *ts;
2537 
2538  THREAD_LOCK_ASSERT(td, MA_OWNED);
2539  ts = td_get_sched(td);
2540  if (THREAD_CAN_SCHED(td, ts->ts_cpu))
2541  return;
2542  if (TD_ON_RUNQ(td)) {
2543  sched_rem(td);
2544  sched_add(td, SRQ_BORING);
2545  return;
2546  }
2547  if (!TD_IS_RUNNING(td))
2548  return;
2549  /*
2550  * Force a switch before returning to userspace. If the
2551  * target thread is not running locally send an ipi to force
2552  * the issue.
2553  */
2554  td->td_flags |= TDF_NEEDRESCHED;
2555  if (td != curthread)
2556  ipi_cpu(ts->ts_cpu, IPI_PREEMPT);
2557 #endif
2558 }
2559 
2560 /*
2561  * Bind a thread to a target cpu.
2562  */
2563 void
2564 sched_bind(struct thread *td, int cpu)
2565 {
2566  struct td_sched *ts;
2567 
2568  THREAD_LOCK_ASSERT(td, MA_OWNED|MA_NOTRECURSED);
2569  KASSERT(td == curthread, ("sched_bind: can only bind curthread"));
2570  ts = td_get_sched(td);
2571  if (ts->ts_flags & TSF_BOUND)
2572  sched_unbind(td);
2573  KASSERT(THREAD_CAN_MIGRATE(td), ("%p must be migratable", td));
2574  ts->ts_flags |= TSF_BOUND;
2575  sched_pin();
2576  if (PCPU_GET(cpuid) == cpu)
2577  return;
2578  ts->ts_cpu = cpu;
2579  /* When we return from mi_switch we'll be on the correct cpu. */
2580  mi_switch(SW_VOL, NULL);
2581 }
2582 
2583 /*
2584  * Release a bound thread.
2585  */
2586 void
2587 sched_unbind(struct thread *td)
2588 {
2589  struct td_sched *ts;
2590 
2591  THREAD_LOCK_ASSERT(td, MA_OWNED);
2592  KASSERT(td == curthread, ("sched_unbind: can only bind curthread"));
2593  ts = td_get_sched(td);
2594  if ((ts->ts_flags & TSF_BOUND) == 0)
2595  return;
2596  ts->ts_flags &= ~TSF_BOUND;
2597  sched_unpin();
2598 }
2599 
2600 int
2601 sched_is_bound(struct thread *td)
2602 {
2603  THREAD_LOCK_ASSERT(td, MA_OWNED);
2604  return (td_get_sched(td)->ts_flags & TSF_BOUND);
2605 }
2606 
2607 /*
2608  * Basic yield call.
2609  */
2610 void
2611 sched_relinquish(struct thread *td)
2612 {
2613  thread_lock(td);
2614  mi_switch(SW_VOL | SWT_RELINQUISH, NULL);
2615  thread_unlock(td);
2616 }
2617 
2618 /*
2619  * Return the total system load.
2620  */
2621 int
2623 {
2624 #ifdef SMP
2625  int total;
2626  int i;
2627 
2628  total = 0;
2629  CPU_FOREACH(i)
2630  total += TDQ_CPU(i)->tdq_sysload;
2631  return (total);
2632 #else
2633  return (TDQ_SELF()->tdq_sysload);
2634 #endif
2635 }
2636 
2637 int
2639 {
2640  return (sizeof(struct proc));
2641 }
2642 
2643 int
2645 {
2646  return (sizeof(struct thread) + sizeof(struct td_sched));
2647 }
2648 
2649 #ifdef SMP
2650 #define TDQ_IDLESPIN(tdq) \
2651  ((tdq)->tdq_cg != NULL && ((tdq)->tdq_cg->cg_flags & CG_FLAG_THREAD) == 0)
2652 #else
2653 #define TDQ_IDLESPIN(tdq) 1
2654 #endif
2655 
2656 /*
2657  * The actual idle process.
2658  */
2659 void
2661 {
2662  struct thread *td;
2663  struct tdq *tdq;
2664  int oldswitchcnt, switchcnt;
2665  int i;
2666 
2667  mtx_assert(&Giant, MA_NOTOWNED);
2668  td = curthread;
2669  tdq = TDQ_SELF();
2670  THREAD_NO_SLEEPING();
2671  oldswitchcnt = -1;
2672  for (;;) {
2673  if (tdq->tdq_load) {
2674  thread_lock(td);
2675  mi_switch(SW_VOL | SWT_IDLE, NULL);
2676  thread_unlock(td);
2677  }
2678  switchcnt = tdq->tdq_switchcnt + tdq->tdq_oldswitchcnt;
2679 #ifdef SMP
2680  if (switchcnt != oldswitchcnt) {
2681  oldswitchcnt = switchcnt;
2682  if (tdq_idled(tdq) == 0)
2683  continue;
2684  }
2685  switchcnt = tdq->tdq_switchcnt + tdq->tdq_oldswitchcnt;
2686 #else
2687  oldswitchcnt = switchcnt;
2688 #endif
2689  /*
2690  * If we're switching very frequently, spin while checking
2691  * for load rather than entering a low power state that
2692  * may require an IPI. However, don't do any busy
2693  * loops while on SMT machines as this simply steals
2694  * cycles from cores doing useful work.
2695  */
2696  if (TDQ_IDLESPIN(tdq) && switchcnt > sched_idlespinthresh) {
2697  for (i = 0; i < sched_idlespins; i++) {
2698  if (tdq->tdq_load)
2699  break;
2700  cpu_spinwait();
2701  }
2702  }
2703 
2704  /* If there was context switch during spin, restart it. */
2705  switchcnt = tdq->tdq_switchcnt + tdq->tdq_oldswitchcnt;
2706  if (tdq->tdq_load != 0 || switchcnt != oldswitchcnt)
2707  continue;
2708 
2709  /* Run main MD idle handler. */
2710  tdq->tdq_cpu_idle = 1;
2711  /*
2712  * Make sure that tdq_cpu_idle update is globally visible
2713  * before cpu_idle() read tdq_load. The order is important
2714  * to avoid race with tdq_notify.
2715  */
2716  atomic_thread_fence_seq_cst();
2717  cpu_idle(switchcnt * 4 > sched_idlespinthresh);
2718  tdq->tdq_cpu_idle = 0;
2719 
2720  /*
2721  * Account thread-less hardware interrupts and
2722  * other wakeup reasons equal to context switches.
2723  */
2724  switchcnt = tdq->tdq_switchcnt + tdq->tdq_oldswitchcnt;
2725  if (switchcnt != oldswitchcnt)
2726  continue;
2727  tdq->tdq_switchcnt++;
2728  oldswitchcnt++;
2729  }
2730 }
2731 
2732 /*
2733  * A CPU is entering for the first time or a thread is exiting.
2734  */
2735 void
2736 sched_throw(struct thread *td)
2737 {
2738  struct thread *newtd;
2739  struct tdq *tdq;
2740 
2741  tdq = TDQ_SELF();
2742  if (td == NULL) {
2743  /* Correct spinlock nesting and acquire the correct lock. */
2744  TDQ_LOCK(tdq);
2745  spinlock_exit();
2746  PCPU_SET(switchtime, cpu_ticks());
2747  PCPU_SET(switchticks, ticks);
2748  } else {
2749  MPASS(td->td_lock == TDQ_LOCKPTR(tdq));
2750  tdq_load_rem(tdq, td);
2751  lock_profile_release_lock(&TDQ_LOCKPTR(tdq)->lock_object);
2752  td->td_lastcpu = td->td_oncpu;
2753  td->td_oncpu = NOCPU;
2754  }
2755  KASSERT(curthread->td_md.md_spinlock_count == 1, ("invalid count"));
2756  newtd = choosethread();
2757  TDQ_LOCKPTR(tdq)->mtx_lock = (uintptr_t)newtd;
2758  cpu_throw(td, newtd); /* doesn't return */
2759 }
2760 
2761 /*
2762  * This is called from fork_exit(). Just acquire the correct locks and
2763  * let fork do the rest of the work.
2764  */
2765 void
2766 sched_fork_exit(struct thread *td)
2767 {
2768  struct tdq *tdq;
2769  int cpuid;
2770 
2771  /*
2772  * Finish setting up thread glue so that it begins execution in a
2773  * non-nested critical section with the scheduler lock held.
2774  */
2775  cpuid = PCPU_GET(cpuid);
2776  tdq = TDQ_CPU(cpuid);
2777  if (TD_IS_IDLETHREAD(td))
2778  td->td_lock = TDQ_LOCKPTR(tdq);
2779  MPASS(td->td_lock == TDQ_LOCKPTR(tdq));
2780  td->td_oncpu = cpuid;
2781  TDQ_LOCK_ASSERT(tdq, MA_OWNED | MA_NOTRECURSED);
2782  lock_profile_obtain_lock_success(
2783  &TDQ_LOCKPTR(tdq)->lock_object, 0, 0, __FILE__, __LINE__);
2784 
2785  KTR_STATE1(KTR_SCHED, "thread", sched_tdname(td), "running",
2786  "prio:%d", td->td_priority);
2787  SDT_PROBE0(sched, , , on__cpu);
2788 }
2789 
2790 /*
2791  * Create on first use to catch odd startup conditons.
2792  */
2793 char *
2794 sched_tdname(struct thread *td)
2795 {
2796 #ifdef KTR
2797  struct td_sched *ts;
2798 
2799  ts = td_get_sched(td);
2800  if (ts->ts_name[0] == '\0')
2801  snprintf(ts->ts_name, sizeof(ts->ts_name),
2802  "%s tid %d", td->td_name, td->td_tid);
2803  return (ts->ts_name);
2804 #else
2805  return (td->td_name);
2806 #endif
2807 }
2808 
2809 #ifdef KTR
2810 void
2811 sched_clear_tdname(struct thread *td)
2812 {
2813  struct td_sched *ts;
2814 
2815  ts = td_get_sched(td);
2816  ts->ts_name[0] = '\0';
2817 }
2818 #endif
2819 
2820 #ifdef SMP
2821 
2822 /*
2823  * Build the CPU topology dump string. Is recursively called to collect
2824  * the topology tree.
2825  */
2826 static int
2827 sysctl_kern_sched_topology_spec_internal(struct sbuf *sb, struct cpu_group *cg,
2828  int indent)
2829 {
2830  char cpusetbuf[CPUSETBUFSIZ];
2831  int i, first;
2832 
2833  sbuf_printf(sb, "%*s<group level=\"%d\" cache-level=\"%d\">\n", indent,
2834  "", 1 + indent / 2, cg->cg_level);
2835  sbuf_printf(sb, "%*s <cpu count=\"%d\" mask=\"%s\">", indent, "",
2836  cg->cg_count, cpusetobj_strprint(cpusetbuf, &cg->cg_mask));
2837  first = TRUE;
2838  for (i = 0; i < MAXCPU; i++) {
2839  if (CPU_ISSET(i, &cg->cg_mask)) {
2840  if (!first)
2841  sbuf_printf(sb, ", ");
2842  else
2843  first = FALSE;
2844  sbuf_printf(sb, "%d", i);
2845  }
2846  }
2847  sbuf_printf(sb, "</cpu>\n");
2848 
2849  if (cg->cg_flags != 0) {
2850  sbuf_printf(sb, "%*s <flags>", indent, "");
2851  if ((cg->cg_flags & CG_FLAG_HTT) != 0)
2852  sbuf_printf(sb, "<flag name=\"HTT\">HTT group</flag>");
2853  if ((cg->cg_flags & CG_FLAG_THREAD) != 0)
2854  sbuf_printf(sb, "<flag name=\"THREAD\">THREAD group</flag>");
2855  if ((cg->cg_flags & CG_FLAG_SMT) != 0)
2856  sbuf_printf(sb, "<flag name=\"SMT\">SMT group</flag>");
2857  sbuf_printf(sb, "</flags>\n");
2858  }
2859 
2860  if (cg->cg_children > 0) {
2861  sbuf_printf(sb, "%*s <children>\n", indent, "");
2862  for (i = 0; i < cg->cg_children; i++)
2863  sysctl_kern_sched_topology_spec_internal(sb,
2864  &cg->cg_child[i], indent+2);
2865  sbuf_printf(sb, "%*s </children>\n", indent, "");
2866  }
2867  sbuf_printf(sb, "%*s</group>\n", indent, "");
2868  return (0);
2869 }
2870 
2871 /*
2872  * Sysctl handler for retrieving topology dump. It's a wrapper for
2873  * the recursive sysctl_kern_smp_topology_spec_internal().
2874  */
2875 static int
2876 sysctl_kern_sched_topology_spec(SYSCTL_HANDLER_ARGS)
2877 {
2878  struct sbuf *topo;
2879  int err;
2880 
2881  KASSERT(cpu_top != NULL, ("cpu_top isn't initialized"));
2882 
2883  topo = sbuf_new_for_sysctl(NULL, NULL, 512, req);
2884  if (topo == NULL)
2885  return (ENOMEM);
2886 
2887  sbuf_printf(topo, "<groups>\n");
2888  err = sysctl_kern_sched_topology_spec_internal(topo, cpu_top, 1);
2889  sbuf_printf(topo, "</groups>\n");
2890 
2891  if (err == 0) {
2892  err = sbuf_finish(topo);
2893  }
2894  sbuf_delete(topo);
2895  return (err);
2896 }
2897 
2898 #endif
2899 
2900 static int
2901 sysctl_kern_quantum(SYSCTL_HANDLER_ARGS)
2902 {
2903  int error, new_val, period;
2904 
2905  period = 1000000 / realstathz;
2906  new_val = period * sched_slice;
2907  error = sysctl_handle_int(oidp, &new_val, 0, req);
2908  if (error != 0 || req->newptr == NULL)
2909  return (error);
2910  if (new_val <= 0)
2911  return (EINVAL);
2912  sched_slice = imax(1, (new_val + period / 2) / period);
2913  sched_slice_min = sched_slice / SCHED_SLICE_MIN_DIVISOR;
2914  hogticks = imax(1, (2 * hz * sched_slice + realstathz / 2) /
2915  realstathz);
2916  return (0);
2917 }
2918 
2919 SYSCTL_NODE(_kern, OID_AUTO, sched, CTLFLAG_RW, 0, "Scheduler");
2920 SYSCTL_STRING(_kern_sched, OID_AUTO, name, CTLFLAG_RD, "ULE", 0,
2921  "Scheduler name");
2922 SYSCTL_PROC(_kern_sched, OID_AUTO, quantum, CTLTYPE_INT | CTLFLAG_RW,
2923  NULL, 0, sysctl_kern_quantum, "I",
2924  "Quantum for timeshare threads in microseconds");
2925 SYSCTL_INT(_kern_sched, OID_AUTO, slice, CTLFLAG_RW, &sched_slice, 0,
2926  "Quantum for timeshare threads in stathz ticks");
2927 SYSCTL_INT(_kern_sched, OID_AUTO, interact, CTLFLAG_RW, &sched_interact, 0,
2928  "Interactivity score threshold");
2929 SYSCTL_INT(_kern_sched, OID_AUTO, preempt_thresh, CTLFLAG_RW,
2930  &preempt_thresh, 0,
2931  "Maximal (lowest) priority for preemption");
2932 SYSCTL_INT(_kern_sched, OID_AUTO, static_boost, CTLFLAG_RW, &static_boost, 0,
2933  "Assign static kernel priorities to sleeping threads");
2934 SYSCTL_INT(_kern_sched, OID_AUTO, idlespins, CTLFLAG_RW, &sched_idlespins, 0,
2935  "Number of times idle thread will spin waiting for new work");
2936 SYSCTL_INT(_kern_sched, OID_AUTO, idlespinthresh, CTLFLAG_RW,
2937  &sched_idlespinthresh, 0,
2938  "Threshold before we will permit idle thread spinning");
2939 #ifdef SMP
2940 SYSCTL_INT(_kern_sched, OID_AUTO, affinity, CTLFLAG_RW, &affinity, 0,
2941  "Number of hz ticks to keep thread affinity for");
2942 SYSCTL_INT(_kern_sched, OID_AUTO, balance, CTLFLAG_RW, &rebalance, 0,
2943  "Enables the long-term load balancer");
2944 SYSCTL_INT(_kern_sched, OID_AUTO, balance_interval, CTLFLAG_RW,
2945  &balance_interval, 0,
2946  "Average period in stathz ticks to run the long-term balancer");
2947 SYSCTL_INT(_kern_sched, OID_AUTO, steal_idle, CTLFLAG_RW, &steal_idle, 0,
2948  "Attempts to steal work from other cores before idling");
2949 SYSCTL_INT(_kern_sched, OID_AUTO, steal_thresh, CTLFLAG_RW, &steal_thresh, 0,
2950  "Minimum load on remote CPU before we'll steal");
2951 SYSCTL_PROC(_kern_sched, OID_AUTO, topology_spec, CTLTYPE_STRING |
2952  CTLFLAG_MPSAFE | CTLFLAG_RD, NULL, 0, sysctl_kern_sched_topology_spec, "A",
2953  "XML dump of detected CPU topology");
2954 #endif
2955 
2956 /* ps compat. All cpu percentages from ULE are weighted. */
2957 static int ccpu = 0;
2958 SYSCTL_INT(_kern, OID_AUTO, ccpu, CTLFLAG_RD, &ccpu, 0, "");
static struct tdq tdq_cpu
Definition: sched_ule.c:290
volatile int smp_started
Definition: subr_smp.c:77
u_int ts_runtime
Definition: sched_ule.c:99
static void sched_initticks(void *dummy)
Definition: sched_ule.c:1419
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Definition: sched_ule.c:102
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Definition: sched_ule.c:84
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Definition: kern_switch.c:368
SYSCTL_PROC(_kern_sched, OID_AUTO, quantum, CTLTYPE_INT|CTLFLAG_RW, NULL, 0, sysctl_kern_quantum, "I", "Quantum for timeshare threads in microseconds")
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Definition: sched_ule.c:241
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Definition: sched_ule.c:1749
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Definition: sched_ule.c:2361
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Definition: sched_ule.c:2163
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Definition: subr_prf.c:542
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Definition: clock_if.m:39
#define TDF_SLICEEND
Definition: sched_ule.c:199
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Definition: sched_ule.c:94
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Definition: sched_ule.c:2117
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Definition: init_main.c:117
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Definition: linker_if.m:86
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Definition: subr_smp.c:78
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Definition: sched_ule.c:98
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Definition: sched_ule.c:166
#define SCHED_PRI_RANGE
Definition: sched_ule.c:168
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Definition: sched_ule.c:1395
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Definition: sched_ule.c:112
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Definition: sched_ule.c:238
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Definition: sched_ule.c:1477
static __inline void tdq_runq_rem(struct tdq *, struct thread *)
Definition: sched_ule.c:509
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Definition: sched_ule.c:1815
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Definition: sched_ule.c:2901
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Definition: sched_ule.c:245
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Definition: sched_ule.c:238
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Definition: sched_ule.c:247
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Definition: sched_ule.c:132
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Definition: subr_pcpu.c:280
static int ccpu
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Definition: sched_4bsd.c:101
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Definition: sched_ule.c:1352
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Definition: sched_4bsd.c:99
char tdq_name[TDQ_NAME_LEN]
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Definition: sched_ule.c:2046
#define TSF_XFERABLE
Definition: sched_ule.c:109
int ts_rltick
Definition: sched_ule.c:96
SYSINIT(sched_setup, SI_SUB_RUN_QUEUE, SI_ORDER_FIRST, sched_setup, NULL)
static void tdq_load_rem(struct tdq *, struct thread *)
Definition: sched_ule.c:553
struct runq tdq_idle
Definition: sched_ule.c:245
SDT_PROBE_DEFINE(sched,,, on__cpu)
u_char tdq_ridx
Definition: sched_ule.c:249
int ts_ltick
Definition: sched_ule.c:100
volatile int tdq_load
Definition: sched_ule.c:233
struct thread * runq_choose_from(struct runq *rq, u_char idx)
Definition: kern_switch.c:492
static int sched_idlespins
Definition: sched_ule.c:224
#define PRI_MAX_INTERACT
Definition: sched_ule.c:131
int ts_slice
Definition: sched_4bsd.c:100
char tdq_name[TDQ_NAME_LEN]
Definition: sched_ule.c:253
#define SCHED_INTERACT_HALF
Definition: sched_ule.c:189
struct runq tdq_realtime
Definition: sched_ule.c:243
#define TDQ_IDLESPIN(tdq)
Definition: sched_ule.c:2653
SDT_PROBE_DEFINE2(sched,,, load__change, "int", "int")
static int sched_idlespinthresh
Definition: sched_ule.c:225
#define TDQ_ID(x)
Definition: sched_ule.c:292
static struct runq runq
Definition: sched_4bsd.c:163
SYSCTL_STRING(_kern_sched, OID_AUTO, name, CTLFLAG_RD, "ULE", 0, "Scheduler name")
void runq_add_pri(struct runq *rq, struct thread *td, u_char pri, int flags)
Definition: kern_switch.c:387
void runq_init(struct runq *rq)
Definition: kern_switch.c:265
#define SCHED_SLICE_MIN_DIVISOR
Definition: sched_ule.c:196
static int sched_slice_min
Definition: sched_ule.c:213
static void tdq_setlowpri(struct tdq *tdq, struct thread *ctd)
Definition: sched_ule.c:597
void sched_throw(struct thread *td)
Definition: sched_ule.c:2736
struct thread * runq_choose(struct runq *rq)
Definition: kern_switch.c:472
void thread_lock_set(struct thread *td, struct mtx *new)
Definition: kern_mutex.c:967
void sched_fork_exit(struct thread *td)
Definition: sched_ule.c:2766
struct cpuset * cpuset_ref(struct cpuset *set)
Definition: kern_cpuset.c:160
void sched_relinquish(struct thread *td)
Definition: sched_ule.c:2611
static int dummy
void tdq_print(int cpu)
Definition: sched_ule.c:395
u_int sched_estcpu(struct thread *td __unused)
Definition: sched_ule.c:2325
Definition: sched_ule.c:232
void sched_wakeup(struct thread *td)
Definition: sched_ule.c:2067
SDT_PROBE_DEFINE4(sched,,, enqueue, "struct thread *", "struct proc *", "void *", "int")
struct runq * ts_runq
Definition: sched_4bsd.c:102
int sched_sizeof_thread(void)
Definition: sched_ule.c:2644
struct mtx __exclusive_cache_line Giant
Definition: kern_mutex.c:171
void sched_switch(struct thread *td, struct thread *newtd, int flags)
Definition: sched_ule.c:1895
void sched_rem(struct thread *td)
Definition: sched_ule.c:2484
u_long flags
#define SCHED_TICK_SECS
Definition: sched_ule.c:145
struct cpu_group * tdq_cg
Definition: sched_ule.c:239
int ts_cpu
Definition: sched_ule.c:95
int sbuf_printf(struct sbuf *s, const char *fmt,...)
Definition: subr_sbuf.c:678
#define SCHED_SLP_RUN_FORK
Definition: sched_ule.c:187
void sched_lend_user_prio(struct thread *td, u_char prio)
Definition: sched_ule.c:1825
DPCPU_DEFINE(sbintime_t, hardclocktime)
#define PRI_MIN_INTERACT
Definition: sched_ule.c:130
static struct thread * tdq_choose(struct tdq *)
Definition: sched_ule.c:1322
static int tickincr
Definition: sched_ule.c:210
int tdq_transferable
Definition: sched_ule.c:236
int sched_is_bound(struct thread *td)
Definition: sched_ule.c:2601
int mask
Definition: subr_acl_nfs4.c:71
static struct mtx * sched_switch_migrate(struct tdq *tdq, struct thread *td, int flags)
Definition: sched_ule.c:1842
int sysctl_handle_int(SYSCTL_HANDLER_ARGS)
Definition: kern_sysctl.c:1478
#define TDQ_SELF()
Definition: sched_ule.c:293
#define TDQ_LOADNAME_LEN
Definition: sched_ule.c:86
#define SCHED_TICK_MAX
Definition: sched_ule.c:147
struct runq tdq_timeshare
Definition: sched_ule.c:251
void sched_clock(struct thread *td)
Definition: sched_ule.c:2268
static void runq_print(struct runq *rq)
Definition: sched_ule.c:367
static void sched_thread_priority(struct thread *, u_char)
Definition: sched_ule.c:1694
SDT_PROBE_DEFINE3(sched,,, change__pri, "struct thread *", "struct proc *", "uint8_t")
void runq_remove(struct runq *rq, struct thread *td)
Definition: kern_switch.c:517
struct runq tdq_realtime
Definition: sched_ule.c:250
static __inline void tdq_runq_add(struct tdq *, struct thread *, int)
Definition: sched_ule.c:458
#define SCHED_PRI_NICE(nice)
Definition: sched_ule.c:172
void sched_affinity(struct thread *td)
Definition: sched_ule.c:2533
int printf(const char *fmt,...)
Definition: subr_prf.c:400
void sched_exit(struct proc *p, struct thread *child)
Definition: sched_ule.c:2176
struct runq tdq_idle
Definition: sched_ule.c:252
#define SCHED_PRI_TICKS(ts)
Definition: sched_ule.c:169
void sbuf_delete(struct sbuf *s)
Definition: subr_sbuf.c:805
#define TDQ_LOCK_FLAGS(t, f)
Definition: sched_ule.c:299
void sched_idletd(void *dummy)
Definition: sched_ule.c:2660
void sched_unlend_prio(struct thread *td, u_char prio)
Definition: sched_ule.c:1765
int tdq_sysload
Definition: sched_ule.c:242
#define TSF_BOUND
Definition: sched_ule.c:108
struct cpu_group * tdq_cg
Definition: sched_ule.c:232
struct runq tdq_timeshare
Definition: sched_ule.c:244
_Static_assert(sizeof(struct thread)+sizeof(struct td_sched)<=sizeof(struct thread0_storage), "increase struct thread0_storage.t0st_sched size")
#define SCHED_TICK_HZ(ts)
Definition: sched_ule.c:149
SYSCTL_INT(_kern_sched, OID_AUTO, slice, CTLFLAG_RW, &sched_slice, 0, "Quantum for timeshare threads in stathz ticks")
static void thread_unblock_switch(struct thread *td, struct mtx *mtx)
Definition: sched_ule.c:1882
int sbuf_finish(struct sbuf *s)
Definition: subr_sbuf.c:740
void sched_preempt(struct thread *td)
Definition: sched_ule.c:2212
static int realstathz
Definition: sched_ule.c:211
volatile int tdq_load
Definition: sched_ule.c:240
#define TDQ_LOCK(t)
Definition: sched_ule.c:298
#define SCHED_SLICE_DEFAULT_DIVISOR
Definition: sched_ule.c:195
#define TDQ_UNLOCK(t)
Definition: sched_ule.c:300
volatile int ticks
Definition: kern_clock.c:386
int sched_load(void)
Definition: sched_ule.c:2622
int hogticks
Definition: kern_synch.c:75
SDT_PROVIDER_DEFINE(sched)
static int sched_interact
Definition: sched_ule.c:209
static int tdq_slice(struct tdq *tdq)
Definition: sched_ule.c:575
static void sched_interact_fork(struct thread *)
Definition: sched_ule.c:1614
int stathz
Definition: kern_clock.c:383
static void sched_priority(struct thread *)
Definition: sched_ule.c:1517
void sched_nice(struct proc *p, int nice)
Definition: sched_ule.c:2027
#define SCHED_SLP_RUN_MAX
Definition: sched_ule.c:186
static void sched_setpreempt(struct thread *td)
Definition: sched_ule.c:2383
int tdq_transferable
Definition: sched_ule.c:243
static int sched_slice
Definition: sched_ule.c:212
char * cpusetobj_strprint(char *buf, const cpuset_t *set)
Definition: kern_cpuset.c:1136
void sched_userret(struct thread *td)
Definition: sched_ule.c:2241
#define TDQ_LOCKPTR(t)
Definition: sched_ule.c:301
void sched_fork(struct thread *td, struct thread *child)
Definition: sched_ule.c:2098
#define SCHED_INTERACT_THRESH
Definition: sched_ule.c:190
#define PRI_MAX_BATCH
Definition: sched_ule.c:133
static void tdq_add(struct tdq *, struct thread *, int)
Definition: sched_ule.c:2409
struct mtx * thread_lock_block(struct thread *td)
Definition: kern_mutex.c:946
u_char tdq_idx
Definition: sched_ule.c:248
#define SCHED_TICK_TARG
Definition: sched_ule.c:146
int sched_runnable(void)
Definition: sched_ule.c:2336
struct mtx_padalign tdq_lock
Definition: sched_ule.c:231
void sched_unbind(struct thread *td)
Definition: sched_ule.c:2587
static int preempt_thresh
Definition: sched_ule.c:221
#define PRI_BATCH_RANGE
Definition: sched_ule.c:128
#define THREAD_CAN_MIGRATE(td)
Definition: sched_ule.c:111
volatile int tdq_cpu_idle
Definition: sched_ule.c:234
void sched_prio(struct thread *td, u_char prio)
Definition: sched_ule.c:1785
void sched_add(struct thread *td, int flags)
Definition: sched_ule.c:2431
short tdq_switchcnt
Definition: sched_ule.c:244
u_char tdq_lowpri
Definition: sched_ule.c:239
u_char tdq_lowpri
Definition: sched_ule.c:246
SYSCTL_NODE(_kern, OID_AUTO, sched, CTLFLAG_RW, 0, "Scheduler")
static void tdq_load_add(struct tdq *, struct thread *)
Definition: sched_ule.c:535
cpu_tick_f * cpu_ticks
Definition: kern_tc.c:2138
void thread_lock_unblock(struct thread *td, struct mtx *new)
Definition: kern_mutex.c:959
#define TDQ_NAME_LEN
Definition: sched_ule.c:85
static int static_boost
Definition: sched_ule.c:223
__FBSDID("$FreeBSD: head/sys/kern/sched_ule.c 327895 2018-01-12 22:48:23Z jeff $")
void sched_bind(struct thread *td, int cpu)
Definition: sched_ule.c:2564
struct sbuf * sbuf_new_for_sysctl(struct sbuf *s, char *buf, int length, struct sysctl_req *req)
Definition: kern_sysctl.c:2170
int hz
Definition: subr_param.c:86
fixpt_t sched_pctcpu(struct thread *td)
Definition: sched_ule.c:2507
int sched_sizeof_proc(void)
Definition: sched_ule.c:2638
static void sched_pctcpu_update(struct td_sched *, int)
Definition: sched_ule.c:1667