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36ec198bd5
freebsd-dev/sys/kern/sched_core.c
David Xu 36ec198bd5 Add scheduler API sched_relinquish(), the API is used to implement 
yield() and sched_yield() syscalls. Every scheduler has its own way
to relinquish cpu, the ULE and CORE schedulers have two internal run-
queues, a timesharing thread which calls yield() syscall should be
moved to inactive queue.
2006-06-15 06:37:39 +00:00

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/*-
* Copyright (c) 2005-2006, David Xu <yfxu@corp.netease.com>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice unmodified, this list of conditions, and the following
* disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_hwpmc_hooks.h"
#include "opt_sched.h"
#define kse td_sched
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kdb.h>
#include <sys/kernel.h>
#include <sys/kthread.h>
#include <sys/ktr.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/resource.h>
#include <sys/resourcevar.h>
#include <sys/sched.h>
#include <sys/smp.h>
#include <sys/sx.h>
#include <sys/sysctl.h>
#include <sys/sysproto.h>
#include <sys/turnstile.h>
#include <sys/unistd.h>
#include <sys/vmmeter.h>
#ifdef KTRACE
#include <sys/uio.h>
#include <sys/ktrace.h>
#endif
#ifdef HWPMC_HOOKS
#include <sys/pmckern.h>
#endif
#include <machine/cpu.h>
#include <machine/smp.h>
/* get process's nice value, skip value 20 which is not supported */
#define PROC_NICE(p) MIN((p)->p_nice, 19)
/* convert nice to kernel thread priority */
#define NICE_TO_PRI(nice) (PUSER + 20 + (nice))
/* get process's static priority */
#define PROC_PRI(p) NICE_TO_PRI(PROC_NICE(p))
/* convert kernel thread priority to user priority */
#define USER_PRI(pri) MIN((pri) - PUSER, 39)
/* convert nice value to user priority */
#define PROC_USER_PRI(p) (PROC_NICE(p) + 20)
/* maximum user priority, highest prio + 1 */
#define MAX_USER_PRI 40
/* maximum kernel priority its nice is 19 */
#define PUSER_MAX (PUSER + 39)
/* ticks and nanosecond converters */
#define NS_TO_HZ(n) ((n) / (1000000000 / hz))
#define HZ_TO_NS(h) ((h) * (1000000000 / hz))
/* ticks and microsecond converters */
#define MS_TO_HZ(m) ((m) / (1000000 / hz))
#define PRI_SCORE_RATIO 25
#define MAX_SCORE (MAX_USER_PRI * PRI_SCORE_RATIO / 100)
#define MAX_SLEEP_TIME (def_timeslice * MAX_SCORE)
#define NS_MAX_SLEEP_TIME (HZ_TO_NS(MAX_SLEEP_TIME))
#define STARVATION_TIME (MAX_SLEEP_TIME)
#define CURRENT_SCORE(kg) \
(MAX_SCORE * NS_TO_HZ((kg)->kg_slptime) / MAX_SLEEP_TIME)
#define SCALE_USER_PRI(x, upri) \
MAX(x * (upri + 1) / (MAX_USER_PRI/2), min_timeslice)
/*
* For a thread whose nice is zero, the score is used to determine
* if it is an interactive thread.
*/
#define INTERACTIVE_BASE_SCORE (MAX_SCORE * 20)/100
/*
* Calculate a score which a thread must have to prove itself is
* an interactive thread.
*/
#define INTERACTIVE_SCORE(ke) \
(PROC_NICE((ke)->ke_proc) * MAX_SCORE / 40 + INTERACTIVE_BASE_SCORE)
/* Test if a thread is an interactive thread */
#define THREAD_IS_INTERACTIVE(ke) \
((ke)->ke_ksegrp->kg_user_pri <= \
PROC_PRI((ke)->ke_proc) - INTERACTIVE_SCORE(ke))
/*
* Calculate how long a thread must sleep to prove itself is an
* interactive sleep.
*/
#define INTERACTIVE_SLEEP_TIME(ke) \
(HZ_TO_NS(MAX_SLEEP_TIME * \
(MAX_SCORE / 2 + INTERACTIVE_SCORE((ke)) + 1) / MAX_SCORE - 1))
#define CHILD_WEIGHT 90
#define PARENT_WEIGHT 90
#define EXIT_WEIGHT 3
#define SCHED_LOAD_SCALE 128UL
#define IDLE 0
#define IDLE_IDLE 1
#define NOT_IDLE 2
#define KQB_LEN (8) /* Number of priority status words. */
#define KQB_L2BPW (5) /* Log2(sizeof(rqb_word_t) * NBBY)). */
#define KQB_BPW (1<<KQB_L2BPW) /* Bits in an rqb_word_t. */
#define KQB_BIT(pri) (1 << ((pri) & (KQB_BPW - 1)))
#define KQB_WORD(pri) ((pri) >> KQB_L2BPW)
#define KQB_FFS(word) (ffs(word) - 1)
#define KQ_NQS 256
/*
* Type of run queue status word.
*/
typedef u_int32_t kqb_word_t;
/*
* Head of run queues.
*/
TAILQ_HEAD(krqhead, kse);
/*
* Bit array which maintains the status of a run queue. When a queue is
* non-empty the bit corresponding to the queue number will be set.
*/
struct krqbits {
kqb_word_t rqb_bits[KQB_LEN];
};
/*
* Run queue structure. Contains an array of run queues on which processes
* are placed, and a structure to maintain the status of each queue.
*/
struct krunq {
struct krqbits rq_status;
struct krqhead rq_queues[KQ_NQS];
};
/*
* The following datastructures are allocated within their parent structure
* but are scheduler specific.
*/
/*
* The schedulable entity that can be given a context to run. A process may
* have several of these.
*/
struct kse {
TAILQ_ENTRY(kse) ke_procq; /* (j/z) Run queue. */
int ke_flags; /* (j) KEF_* flags. */
struct thread *ke_thread; /* (*) Active associated thread. */
fixpt_t ke_pctcpu; /* (j) %cpu during p_swtime. */
u_char ke_rqindex; /* (j) Run queue index. */
enum {
KES_THREAD = 0x0, /* slaved to thread state */
KES_ONRUNQ
} ke_state; /* (j) thread sched specific status. */
int ke_slice;
struct krunq *ke_runq;
int ke_cpu; /* CPU that we have affinity for. */
int ke_activated;
uint64_t ke_timestamp;
uint64_t ke_lastran;
#ifdef SMP
int ke_tocpu;
#endif
/* The following variables are only used for pctcpu calculation */
int ke_ltick; /* Last tick that we were running on */
int ke_ftick; /* First tick that we were running on */
int ke_ticks; /* Tick count */
};
#define td_kse td_sched
#define ke_proc ke_thread->td_proc
#define ke_ksegrp ke_thread->td_ksegrp
/* flags kept in ke_flags */
#define KEF_ASSIGNED 0x0001 /* Thread is being migrated. */
#define KEF_BOUND 0x0002 /* Thread can not migrate. */
#define KEF_XFERABLE 0x0004 /* Thread was added as transferable. */
#define KEF_HOLD 0x0008 /* Thread is temporarily bound. */
#define KEF_REMOVED 0x0010 /* Thread was removed while ASSIGNED */
#define KEF_INTERNAL 0x0020 /* Thread added due to migration. */
#define KEF_PREEMPTED 0x0040 /* Thread was preempted. */
#define KEF_MIGRATING 0x0080 /* Thread is migrating. */
#define KEF_SLEEP 0x0100 /* Thread did sleep. */
#define KEF_DIDRUN 0x2000 /* Thread actually ran. */
#define KEF_EXIT 0x4000 /* Thread is being killed. */
#define KEF_NEXTRQ 0x8000 /* Thread should be in next queue. */
#define KEF_FIRST_SLICE 0x10000 /* Thread has first time slice left. */
struct kg_sched {
struct thread *skg_last_assigned; /* (j) Last thread assigned to */
/* the system scheduler */
u_long skg_slptime; /* (j) Number of ticks we vol. slept */
u_long skg_runtime; /* (j) Temp total run time. */
int skg_avail_opennings; /* (j) Num unfilled slots in group.*/
int skg_concurrency; /* (j) Num threads requested in group.*/
};
#define kg_last_assigned kg_sched->skg_last_assigned
#define kg_avail_opennings kg_sched->skg_avail_opennings
#define kg_concurrency kg_sched->skg_concurrency
#define kg_slptime kg_sched->skg_slptime
#define kg_runtime kg_sched->skg_runtime
#define SLOT_RELEASE(kg) (kg)->kg_avail_opennings++
#define SLOT_USE(kg) (kg)->kg_avail_opennings--
/*
* Cpu percentage computation macros and defines.
*
* SCHED_CPU_TIME: Number of seconds to average the cpu usage across.
* SCHED_CPU_TICKS: Number of hz ticks to average the cpu usage across.
*/
#define SCHED_CPU_TIME 10
#define SCHED_CPU_TICKS (hz * SCHED_CPU_TIME)
/*
* kseq - per processor runqs and statistics.
*/
struct kseq {
struct krunq ksq_idle; /* Queue of IDLE threads. */
struct krunq ksq_timeshare[2]; /* Run queues for !IDLE. */
struct krunq *ksq_next; /* Next timeshare queue. */
struct krunq *ksq_curr; /* Current queue. */
int ksq_load_timeshare; /* Load for timeshare. */
int ksq_load_idle;
int ksq_load; /* Aggregate load. */
int ksq_sysload; /* For loadavg, !P_NOLOAD */
uint64_t ksq_expired_timestamp;
uint64_t ksq_last_timestamp;
signed char ksq_best_expired_nice;
#ifdef SMP
int ksq_transferable;
LIST_ENTRY(kseq) ksq_siblings; /* Next in kseq group. */
struct kseq_group *ksq_group; /* Our processor group. */
struct thread *ksq_migrated;
TAILQ_HEAD(,kse) ksq_migrateq;
int ksq_avgload;
#endif
};
#ifdef SMP
/*
* kseq groups are groups of processors which can cheaply share threads. When
* one processor in the group goes idle it will check the runqs of the other
* processors in its group prior to halting and waiting for an interrupt.
* These groups are suitable for SMT (Symetric Multi-Threading) and not NUMA.
* In a NUMA environment we'd want an idle bitmap per group and a two tiered
* load balancer.
*/
struct kseq_group {
int ksg_cpus; /* Count of CPUs in this kseq group. */
cpumask_t ksg_cpumask; /* Mask of cpus in this group. */
cpumask_t ksg_idlemask; /* Idle cpus in this group. */
cpumask_t ksg_mask; /* Bit mask for first cpu. */
int ksg_transferable; /* Transferable load of this group. */
LIST_HEAD(, kseq) ksg_members; /* Linked list of all members. */
int ksg_balance_tick;
};
#endif
static struct kse kse0;
static struct kg_sched kg_sched0;
static int min_timeslice = 5;
static int def_timeslice = 100;
static int granularity = 10;
static int realstathz;
/*
* One kse queue per processor.
*/
#ifdef SMP
static cpumask_t kseq_idle;
static int ksg_maxid;
static struct kseq kseq_cpu[MAXCPU];
static struct kseq_group kseq_groups[MAXCPU];
static int balance_tick;
static int balance_interval = 1;
static int balance_interval_max = 32;
static int balance_interval_min = 8;
static int balance_busy_factor = 32;
static int imbalance_pct = 25;
static int imbalance_pct2 = 50;
static int ignore_topology = 1;
#define KSEQ_SELF() (&kseq_cpu[PCPU_GET(cpuid)])
#define KSEQ_CPU(x) (&kseq_cpu[(x)])
#define KSEQ_ID(x) ((x) - kseq_cpu)
#define KSEQ_GROUP(x) (&kseq_groups[(x)])
#else /* !SMP */
static struct kseq kseq_cpu;
#define KSEQ_SELF() (&kseq_cpu)
#define KSEQ_CPU(x) (&kseq_cpu)
#endif
/* decay 95% of `p_pctcpu' in 60 seconds; see CCPU_SHIFT before changing */
static fixpt_t ccpu = 0.95122942450071400909 * FSCALE; /* exp(-1/20) */
SYSCTL_INT(_kern, OID_AUTO, ccpu, CTLFLAG_RD, &ccpu, 0, "");
static void sched_setup(void *dummy);
SYSINIT(sched_setup, SI_SUB_RUN_QUEUE, SI_ORDER_FIRST, sched_setup, NULL);
static void sched_initticks(void *dummy);
SYSINIT(sched_initticks, SI_SUB_CLOCKS, SI_ORDER_THIRD, sched_initticks, NULL)
static SYSCTL_NODE(_kern, OID_AUTO, sched, CTLFLAG_RW, 0, "Scheduler");
SYSCTL_STRING(_kern_sched, OID_AUTO, name, CTLFLAG_RD, "core", 0,
"Scheduler name");
#ifdef SMP
SYSCTL_INT(_kern_sched, OID_AUTO, imbalance_pct, CTLFLAG_RW,
&imbalance_pct, 0, "");
SYSCTL_INT(_kern_sched, OID_AUTO, imbalance_pct2, CTLFLAG_RW,
&imbalance_pct2, 0, "");
SYSCTL_INT(_kern_sched, OID_AUTO, balance_interval_min, CTLFLAG_RW,
&balance_interval_min, 0, "");
SYSCTL_INT(_kern_sched, OID_AUTO, balance_interval_max, CTLFLAG_RW,
&balance_interval_max, 0, "");
#endif
static void slot_fill(struct ksegrp *);
static void krunq_add(struct krunq *, struct kse *, int flags);
static struct kse *krunq_choose(struct krunq *);
static void krunq_clrbit(struct krunq *rq, int pri);
static int krunq_findbit(struct krunq *rq);
static void krunq_init(struct krunq *);
static void krunq_remove(struct krunq *, struct kse *);
#ifdef SMP
static struct kse *krunq_steal(struct krunq *rq, int my_cpu);
#endif
static struct kse * kseq_choose(struct kseq *);
static void kseq_load_add(struct kseq *, struct kse *);
static void kseq_load_rem(struct kseq *, struct kse *);
static void kseq_runq_add(struct kseq *, struct kse *, int);
static void kseq_runq_rem(struct kseq *, struct kse *);
static void kseq_setup(struct kseq *);
static int sched_is_timeshare(struct ksegrp *kg);
static struct kse *sched_choose(void);
static int sched_calc_pri(struct ksegrp *kg);
static int sched_starving(struct kseq *, uint64_t, struct kse *);
static void sched_pctcpu_update(struct kse *);
static void sched_thread_priority(struct thread *, u_char);
static uint64_t sched_timestamp(void);
static int sched_recalc_pri(struct kse *ke, uint64_t now);
static int sched_timeslice(struct kse *ke);
static void sched_update_runtime(struct kse *ke, uint64_t now);
static void sched_commit_runtime(struct kse *ke);
#ifdef SMP
static void sched_balance_tick(int my_cpu, int idle);
static int sched_balance_idle(int my_cpu, int idle);
static int sched_balance(int my_cpu, int idle);
struct kseq_group *sched_find_busiest_group(int my_cpu, int idle,
int *imbalance);
static struct kseq *sched_find_busiest_queue(struct kseq_group *ksg);
static int sched_find_idlest_cpu(struct kse *ke, int cpu);
static int sched_pull_threads(struct kseq *high, struct kseq *myksq,
int max_move, int idle);
static int sched_pull_one(struct kseq *from, struct kseq *myksq, int idle);
static struct kse *sched_steal(struct kseq *, int my_cpu, int stealidle);
static int sched_idled(struct kseq *, int idle);
static int sched_find_idle_cpu(int defcpu);
static void migrated_setup(void *dummy);
static void migrated(void *dummy);
SYSINIT(migrated_setup, SI_SUB_KTHREAD_IDLE, SI_ORDER_MIDDLE, migrated_setup,
NULL);
#endif /* SMP */
static inline int
kse_pinned(struct kse *ke)
{
if (ke->ke_thread->td_pinned)
return (1);
if (ke->ke_flags & KEF_BOUND)
return (1);
return (0);
}
#ifdef SMP
static inline int
kse_can_migrate(struct kse *ke)
{
if (kse_pinned(ke))
return (0);
return (1);
}
#endif
/*
* Initialize a run structure.
*/
static void
krunq_init(struct krunq *rq)
{
int i;
bzero(rq, sizeof *rq);
for (i = 0; i < KQ_NQS; i++)
TAILQ_INIT(&rq->rq_queues[i]);
}
/*
* Clear the status bit of the queue corresponding to priority level pri,
* indicating that it is empty.
*/
static inline void
krunq_clrbit(struct krunq *rq, int pri)
{
struct krqbits *rqb;
rqb = &rq->rq_status;
rqb->rqb_bits[KQB_WORD(pri)] &= ~KQB_BIT(pri);
}
/*
* Find the index of the first non-empty run queue. This is done by
* scanning the status bits, a set bit indicates a non-empty queue.
*/
static int
krunq_findbit(struct krunq *rq)
{
struct krqbits *rqb;
int pri;
int i;
rqb = &rq->rq_status;
for (i = 0; i < KQB_LEN; i++) {
if (rqb->rqb_bits[i]) {
pri = KQB_FFS(rqb->rqb_bits[i]) + (i << KQB_L2BPW);
return (pri);
}
}
return (-1);
}
/*
* Set the status bit of the queue corresponding to priority level pri,
* indicating that it is non-empty.
*/
static inline void
krunq_setbit(struct krunq *rq, int pri)
{
struct krqbits *rqb;
rqb = &rq->rq_status;
rqb->rqb_bits[KQB_WORD(pri)] |= KQB_BIT(pri);
}
/*
* Add the KSE to the queue specified by its priority, and set the
* corresponding status bit.
*/
static void
krunq_add(struct krunq *rq, struct kse *ke, int flags)
{
struct krqhead *rqh;
int pri;
pri = ke->ke_thread->td_priority;
ke->ke_rqindex = pri;
krunq_setbit(rq, pri);
rqh = &rq->rq_queues[pri];
if (flags & SRQ_PREEMPTED)
TAILQ_INSERT_HEAD(rqh, ke, ke_procq);
else
TAILQ_INSERT_TAIL(rqh, ke, ke_procq);
}
/*
* Find the highest priority process on the run queue.
*/
static struct kse *
krunq_choose(struct krunq *rq)
{
struct krqhead *rqh;
struct kse *ke;
int pri;
mtx_assert(&sched_lock, MA_OWNED);
if ((pri = krunq_findbit(rq)) != -1) {
rqh = &rq->rq_queues[pri];
ke = TAILQ_FIRST(rqh);
KASSERT(ke != NULL, ("runq_choose: no proc on busy queue"));
return (ke);
}
return (NULL);
}
/*
* Remove the KSE from the queue specified by its priority, and clear the
* corresponding status bit if the queue becomes empty.
* Caller must set ke->ke_state afterwards.
*/
static void
krunq_remove(struct krunq *rq, struct kse *ke)
{
struct krqhead *rqh;
int pri;
KASSERT(ke->ke_proc->p_sflag & PS_INMEM,
("runq_remove: process swapped out"));
pri = ke->ke_rqindex;
rqh = &rq->rq_queues[pri];
KASSERT(ke != NULL, ("krunq_remove: no proc on busy queue"));
TAILQ_REMOVE(rqh, ke, ke_procq);
if (TAILQ_EMPTY(rqh))
krunq_clrbit(rq, pri);
}
#ifdef SMP
static struct kse *
krunq_steal(struct krunq *rq, int my_cpu)
{
struct krqhead *rqh;
struct krqbits *rqb;
struct kse *ke;
kqb_word_t word;
int i, bit;
(void)my_cpu;
mtx_assert(&sched_lock, MA_OWNED);
rqb = &rq->rq_status;
for (i = 0; i < KQB_LEN; i++) {
if ((word = rqb->rqb_bits[i]) == 0)
continue;
do {
bit = KQB_FFS(word);
rqh = &rq->rq_queues[bit + (i << KQB_L2BPW)];
TAILQ_FOREACH(ke, rqh, ke_procq) {
if (kse_can_migrate(ke))
return (ke);
}
word &= ~((kqb_word_t)1 << bit);
} while (word != 0);
}
return (NULL);
}
#endif
static inline void
kseq_runq_add(struct kseq *kseq, struct kse *ke, int flags)
{
#ifdef SMP
if (kse_pinned(ke) == 0) {
kseq->ksq_transferable++;
kseq->ksq_group->ksg_transferable++;
ke->ke_flags |= KEF_XFERABLE;
}
#endif
if (ke->ke_flags & KEF_PREEMPTED)
flags |= SRQ_PREEMPTED;
krunq_add(ke->ke_runq, ke, flags);
}
static inline void
kseq_runq_rem(struct kseq *kseq, struct kse *ke)
{
#ifdef SMP
if (ke->ke_flags & KEF_XFERABLE) {
kseq->ksq_transferable--;
kseq->ksq_group->ksg_transferable--;
ke->ke_flags &= ~KEF_XFERABLE;
}
#endif
krunq_remove(ke->ke_runq, ke);
ke->ke_runq = NULL;
}
static void
kseq_load_add(struct kseq *kseq, struct kse *ke)
{
int class;
mtx_assert(&sched_lock, MA_OWNED);
#ifdef SMP
if (__predict_false(ke->ke_thread == kseq->ksq_migrated))
return;
#endif
class = PRI_BASE(ke->ke_ksegrp->kg_pri_class);
if (class == PRI_TIMESHARE)
kseq->ksq_load_timeshare++;
else if (class == PRI_IDLE)
kseq->ksq_load_idle++;
kseq->ksq_load++;
if ((ke->ke_proc->p_flag & P_NOLOAD) == 0)
kseq->ksq_sysload++;
}
static void
kseq_load_rem(struct kseq *kseq, struct kse *ke)
{
int class;
mtx_assert(&sched_lock, MA_OWNED);
#ifdef SMP
if (__predict_false(ke->ke_thread == kseq->ksq_migrated))
return;
#endif
class = PRI_BASE(ke->ke_ksegrp->kg_pri_class);
if (class == PRI_TIMESHARE)
kseq->ksq_load_timeshare--;
else if (class == PRI_IDLE)
kseq->ksq_load_idle--;
kseq->ksq_load--;
if ((ke->ke_proc->p_flag & P_NOLOAD) == 0)
kseq->ksq_sysload--;
}
/*
* Pick the highest priority task we have and return it.
*/
static struct kse *
kseq_choose(struct kseq *kseq)
{
struct krunq *swap;
struct kse *ke;
mtx_assert(&sched_lock, MA_OWNED);
ke = krunq_choose(kseq->ksq_curr);
if (ke != NULL)
return (ke);
kseq->ksq_best_expired_nice = 21;
kseq->ksq_expired_timestamp = 0;
swap = kseq->ksq_curr;
kseq->ksq_curr = kseq->ksq_next;
kseq->ksq_next = swap;
ke = krunq_choose(kseq->ksq_curr);
if (ke != NULL)
return (ke);
return krunq_choose(&kseq->ksq_idle);
}
static inline uint64_t
sched_timestamp(void)
{
uint64_t now = cputick2usec(cpu_ticks()) * 1000;
return (now);
}
static inline int
sched_timeslice(struct kse *ke)
{
struct proc *p = ke->ke_proc;
if (ke->ke_proc->p_nice < 0)
return SCALE_USER_PRI(def_timeslice*4, PROC_USER_PRI(p));
else
return SCALE_USER_PRI(def_timeslice, PROC_USER_PRI(p));
}
static inline int
sched_is_timeshare(struct ksegrp *kg)
{
/*
* XXX P_KTHREAD should be checked, but unfortunately, the
* readonly flag resides in a volatile member p_flag, reading
* it could cause lots of cache line sharing and invalidating.
*/
return (kg->kg_pri_class == PRI_TIMESHARE);
}
static int
sched_calc_pri(struct ksegrp *kg)
{
int score, pri;
if (__predict_false(!sched_is_timeshare(kg)))
return (kg->kg_user_pri);
score = CURRENT_SCORE(kg) - MAX_SCORE / 2;
pri = PROC_PRI(kg->kg_proc) - score;
if (pri < PUSER)
pri = PUSER;
if (pri > PUSER_MAX)
pri = PUSER_MAX;
return (pri);
}
static int
sched_recalc_pri(struct kse *ke, uint64_t now)
{
uint64_t delta;
unsigned int sleep_time;
struct ksegrp *kg;
kg = ke->ke_ksegrp;
delta = now - ke->ke_timestamp;
if (__predict_false(!sched_is_timeshare(kg)))
return (kg->kg_user_pri);
if (delta > NS_MAX_SLEEP_TIME)
sleep_time = NS_MAX_SLEEP_TIME;
else
sleep_time = (unsigned int)delta;
if (__predict_false(sleep_time == 0))
goto out;
if (ke->ke_activated != -1 &&
sleep_time > INTERACTIVE_SLEEP_TIME(ke)) {
kg->kg_slptime = HZ_TO_NS(MAX_SLEEP_TIME - def_timeslice);
} else {
sleep_time *= (MAX_SCORE - CURRENT_SCORE(kg)) ? : 1;
/*
* If thread is waking from uninterruptible sleep, it is
* unlikely an interactive sleep, limit its sleep time to
* prevent it from being an interactive thread.
*/
if (ke->ke_activated == -1) {
if (kg->kg_slptime >= INTERACTIVE_SLEEP_TIME(ke))
sleep_time = 0;
else if (kg->kg_slptime + sleep_time >=
INTERACTIVE_SLEEP_TIME(ke)) {
kg->kg_slptime = INTERACTIVE_SLEEP_TIME(ke);
sleep_time = 0;
}
}
/*
* Thread gets priority boost here.
*/
kg->kg_slptime += sleep_time;
/* Sleep time should never be larger than maximum */
if (kg->kg_slptime > NS_MAX_SLEEP_TIME)
kg->kg_slptime = NS_MAX_SLEEP_TIME;
}
out:
return (sched_calc_pri(kg));
}
static void
sched_update_runtime(struct kse *ke, uint64_t now)
{
uint64_t runtime;
struct ksegrp *kg = ke->ke_ksegrp;
if (sched_is_timeshare(kg)) {
if ((int64_t)(now - ke->ke_timestamp) < NS_MAX_SLEEP_TIME) {
runtime = now - ke->ke_timestamp;
if ((int64_t)(now - ke->ke_timestamp) < 0)
runtime = 0;
} else {
runtime = NS_MAX_SLEEP_TIME;
}
runtime /= (CURRENT_SCORE(kg) ? : 1);
kg->kg_runtime += runtime;
ke->ke_timestamp = now;
}
}
static void
sched_commit_runtime(struct kse *ke)
{
struct ksegrp *kg = ke->ke_ksegrp;
if (kg->kg_runtime > kg->kg_slptime)
kg->kg_slptime = 0;
else
kg->kg_slptime -= kg->kg_runtime;
kg->kg_runtime = 0;
}
#ifdef SMP
/* staged balancing operations between CPUs */
#define CPU_OFFSET(cpu) (hz * cpu / MAXCPU)
static void
sched_balance_tick(int my_cpu, int idle)
{
struct kseq *kseq = KSEQ_CPU(my_cpu);
unsigned t = ticks + CPU_OFFSET(my_cpu);
int old_load, cur_load;
int interval;
old_load = kseq->ksq_avgload;
cur_load = kseq->ksq_load * SCHED_LOAD_SCALE;
if (cur_load > old_load)
old_load++;
kseq->ksq_avgload = (old_load + cur_load) / 2;
interval = balance_interval;
if (idle == NOT_IDLE)
interval *= balance_busy_factor;
interval = MS_TO_HZ(interval);
if (interval == 0)
interval = 1;
if (t - balance_tick >= interval) {
sched_balance(my_cpu, idle);
balance_tick += interval;
}
}
static int
sched_balance(int my_cpu, int idle)
{
struct kseq_group *high_group;
struct kseq *high_queue;
int imbalance, pulled;
mtx_assert(&sched_lock, MA_OWNED);
high_group = sched_find_busiest_group(my_cpu, idle, &imbalance);
if (high_group == NULL)
goto out;
high_queue = sched_find_busiest_queue(high_group);
if (high_queue == NULL)
goto out;
pulled = sched_pull_threads(high_queue, KSEQ_CPU(my_cpu), imbalance,
idle);
if (pulled == 0) {
if (balance_interval < balance_interval_max)
balance_interval++;
} else {
balance_interval = balance_interval_min;
}
return (pulled);
out:
if (balance_interval < balance_interval_max)
balance_interval *= 2;
return (0);
}
static int
sched_balance_idle(int my_cpu, int idle)
{
struct kseq_group *high_group;
struct kseq *high_queue;
int imbalance, pulled;
mtx_assert(&sched_lock, MA_OWNED);
high_group = sched_find_busiest_group(my_cpu, idle, &imbalance);
if (high_group == NULL)
return (0);
high_queue = sched_find_busiest_queue(high_group);
if (high_queue == NULL)
return (0);
pulled = sched_pull_threads(high_queue, KSEQ_CPU(my_cpu), imbalance,
idle);
return (pulled);
}
static inline int
kseq_source_load(struct kseq *ksq)
{
int load = ksq->ksq_load * SCHED_LOAD_SCALE;
return (MIN(ksq->ksq_avgload, load));
}
static inline int
kseq_dest_load(struct kseq *ksq)
{
int load = ksq->ksq_load * SCHED_LOAD_SCALE;
return (MAX(ksq->ksq_avgload, load));
}
struct kseq_group *
sched_find_busiest_group(int my_cpu, int idle, int *imbalance)
{
static unsigned stage_cpu;
struct kseq_group *high;
struct kseq_group *ksg;
struct kseq *my_ksq, *ksq;
int my_load, high_load, avg_load, total_load, load;
int diff, cnt, i;
*imbalance = 0;
if (__predict_false(smp_started == 0))
return (NULL);
my_ksq = KSEQ_CPU(my_cpu);
high = NULL;
high_load = total_load = my_load = 0;
i = (stage_cpu++) % (ksg_maxid + 1);
for (cnt = 0; cnt <= ksg_maxid; cnt++) {
ksg = KSEQ_GROUP(i);
/*
* Find the CPU with the highest load that has some
* threads to transfer.
*/
load = 0;
LIST_FOREACH(ksq, &ksg->ksg_members, ksq_siblings) {
if (ksg == my_ksq->ksq_group)
load += kseq_dest_load(ksq);
else
load += kseq_source_load(ksq);
}
if (ksg == my_ksq->ksq_group) {
my_load = load;
} else if (load > high_load && ksg->ksg_transferable) {
high = ksg;
high_load = load;
}
total_load += load;
if (++i > ksg_maxid)
i = 0;
}
avg_load = total_load / (ksg_maxid + 1);
if (high == NULL)
return (NULL);
if (my_load >= avg_load ||
(high_load - my_load) * 100 < imbalance_pct * my_load) {
if (idle == IDLE_IDLE ||
(idle == IDLE && high_load > SCHED_LOAD_SCALE)) {
*imbalance = 1;
return (high);
} else {
return (NULL);
}
}
/*
* Pick a minimum imbalance value, avoid raising our load
* higher than average and pushing busiest load under average.
*/
diff = MIN(high_load - avg_load, avg_load - my_load);
if (diff < SCHED_LOAD_SCALE) {
if (high_load - my_load >= SCHED_LOAD_SCALE * 2) {
*imbalance = 1;
return (high);
}
}
*imbalance = diff / SCHED_LOAD_SCALE;
return (high);
}
static struct kseq *
sched_find_busiest_queue(struct kseq_group *ksg)
{
struct kseq *kseq, *high = NULL;
int load, high_load = 0;
LIST_FOREACH(kseq, &ksg->ksg_members, ksq_siblings) {
load = kseq_source_load(kseq);
if (load > high_load) {
high_load = load;
high = kseq;
}
}
return (high);
}
static int
sched_pull_threads(struct kseq *high, struct kseq *myksq, int max_pull,
int idle)
{
int pulled, i;
mtx_assert(&sched_lock, MA_OWNED);
pulled = 0;
for (i = 0; i < max_pull; i++) {
if (sched_pull_one(high, myksq, idle))
pulled++;
else
break;
}
return (pulled);
}
static int
sched_pull_one(struct kseq *from, struct kseq *myksq, int idle)
{
struct kseq *kseq;
struct kse *ke;
struct krunq *destq;
int class;
mtx_assert(&sched_lock, MA_OWNED);
kseq = from;
ke = sched_steal(kseq, KSEQ_ID(myksq), idle);
if (ke == NULL) {
/* doing balance in same group */
if (from->ksq_group == myksq->ksq_group)
return (0);
struct kseq_group *ksg;
ksg = kseq->ksq_group;
LIST_FOREACH(kseq, &ksg->ksg_members, ksq_siblings) {
if (kseq == from || kseq == myksq ||
kseq->ksq_transferable == 0)
continue;
ke = sched_steal(kseq, KSEQ_ID(myksq), idle);
break;
}
if (ke == NULL)
return (0);
}
ke->ke_timestamp = ke->ke_timestamp + myksq->ksq_last_timestamp -
kseq->ksq_last_timestamp;
ke->ke_lastran = 0;
if (ke->ke_runq == from->ksq_curr)
destq = myksq->ksq_curr;
else if (ke->ke_runq == from->ksq_next)
destq = myksq->ksq_next;
else
destq = &myksq->ksq_idle;
kseq_runq_rem(kseq, ke);
kseq_load_rem(kseq, ke);
ke->ke_cpu = KSEQ_ID(myksq);
ke->ke_runq = destq;
ke->ke_state = KES_ONRUNQ;
kseq_runq_add(myksq, ke, 0);
kseq_load_add(myksq, ke);
class = PRI_BASE(ke->ke_ksegrp->kg_pri_class);
if (class != PRI_IDLE) {
if (kseq_idle & myksq->ksq_group->ksg_mask)
kseq_idle &= ~myksq->ksq_group->ksg_mask;
if (myksq->ksq_group->ksg_idlemask & PCPU_GET(cpumask))
myksq->ksq_group->ksg_idlemask &= ~PCPU_GET(cpumask);
}
if (ke->ke_thread->td_priority < curthread->td_priority)
curthread->td_flags |= TDF_NEEDRESCHED;
return (1);
}
static struct kse *
sched_steal(struct kseq *kseq, int my_cpu, int idle)
{
struct kse *ke;
/*
* Steal from expired queue first to try to get a non-interactive
* task that may not have run for a while.
*/
if ((ke = krunq_steal(kseq->ksq_next, my_cpu)) != NULL)
return (ke);
if ((ke = krunq_steal(kseq->ksq_curr, my_cpu)) != NULL)
return (ke);
if (idle == IDLE_IDLE)
return (krunq_steal(&kseq->ksq_idle, my_cpu));
return (NULL);
}
static int
sched_idled(struct kseq *kseq, int idle)
{
struct kseq_group *ksg;
struct kseq *steal;
mtx_assert(&sched_lock, MA_OWNED);
ksg = kseq->ksq_group;
/*
* If we're in a cpu group, try and steal kses from another cpu in
* the group before idling.
*/
if (ksg->ksg_cpus > 1 && ksg->ksg_transferable) {
LIST_FOREACH(steal, &ksg->ksg_members, ksq_siblings) {
if (steal == kseq || steal->ksq_transferable == 0)
continue;
if (sched_pull_one(steal, kseq, idle))
return (0);
}
}
if (sched_balance_idle(PCPU_GET(cpuid), idle))
return (0);
/*
* We only set the idled bit when all of the cpus in the group are
* idle. Otherwise we could get into a situation where a KSE bounces
* back and forth between two idle cores on seperate physical CPUs.
*/
ksg->ksg_idlemask |= PCPU_GET(cpumask);
if (ksg->ksg_idlemask != ksg->ksg_cpumask)
return (1);
kseq_idle |= ksg->ksg_mask;
return (1);
}
static int
sched_find_idle_cpu(int defcpu)
{
struct pcpu *pcpu;
struct kseq_group *ksg;
struct kseq *ksq;
int cpu;
mtx_assert(&sched_lock, MA_OWNED);
ksq = KSEQ_CPU(defcpu);
ksg = ksq->ksq_group;
pcpu = pcpu_find(defcpu);
if (ksg->ksg_idlemask & pcpu->pc_cpumask)
return (defcpu);
/* Try to find a fully idled cpu. */
if (kseq_idle) {
cpu = ffs(kseq_idle);
if (cpu)
goto migrate;
}
/*
* If another cpu in this group has idled, assign a thread over
* to them after checking to see if there are idled groups.
*/
if (ksg->ksg_idlemask) {
cpu = ffs(ksg->ksg_idlemask);
if (cpu)
goto migrate;
}
return (defcpu);
migrate:
/*
* Now that we've found an idle CPU, migrate the thread.
*/
cpu--;
return (cpu);
}
static int
sched_find_idlest_cpu(struct kse *ke, int cpu)
{
static unsigned stage_cpu;
struct kseq_group *ksg;
struct kseq *ksq;
int load, min_load = INT_MAX;
int first = 1;
int idlest = -1;
int i, cnt;
(void)ke;
if (__predict_false(smp_started == 0))
return (cpu);
first = 1;
i = (stage_cpu++) % (ksg_maxid + 1);
for (cnt = 0; cnt <= ksg_maxid; cnt++) {
ksg = KSEQ_GROUP(i);
LIST_FOREACH(ksq, &ksg->ksg_members, ksq_siblings) {
load = kseq_source_load(ksq);
if (first || load < min_load) {
first = 0;
load = min_load;
idlest = KSEQ_ID(ksq);
}
}
if (++i > ksg_maxid)
i = 0;
}
return (idlest);
}
static void
migrated_setup(void *dummy)
{
struct kseq *kseq;
struct proc *p;
struct thread *td;
int i, error;
for (i = 0; i < MAXCPU; i++) {
if (CPU_ABSENT(i))
continue;
kseq = &kseq_cpu[i];
error = kthread_create(migrated, kseq, &p, RFSTOPPED, 0,
"migrated%d", i);
if (error)
panic("can not create migration thread");
PROC_LOCK(p);
p->p_flag |= P_NOLOAD;
mtx_lock_spin(&sched_lock);
td = FIRST_THREAD_IN_PROC(p);
td->td_kse->ke_flags |= KEF_BOUND;
td->td_kse->ke_cpu = i;
kseq->ksq_migrated = td;
sched_class(td->td_ksegrp, PRI_ITHD);
td->td_kse->ke_runq = kseq->ksq_curr;
sched_prio(td, PRI_MIN);
SLOT_USE(td->td_ksegrp);
kseq_runq_add(kseq, td->td_kse, 0);
td->td_kse->ke_state = KES_ONRUNQ;
mtx_unlock_spin(&sched_lock);
PROC_UNLOCK(p);
}
}
static void
migrated(void *dummy)
{
struct thread *td = curthread;
struct kseq *kseq = KSEQ_SELF();
struct kse *ke;
mtx_lock_spin(&sched_lock);
for (;;) {
while ((ke = TAILQ_FIRST(&kseq->ksq_migrateq)) != NULL) {
TAILQ_REMOVE(&kseq->ksq_migrateq, ke, ke_procq);
kseq_load_rem(kseq, ke);
ke->ke_flags &= ~KEF_MIGRATING;
ke->ke_cpu = ke->ke_tocpu;
setrunqueue(ke->ke_thread, SRQ_BORING);
}
TD_SET_IWAIT(td);
mi_switch(SW_VOL, NULL);
}
mtx_unlock_spin(&sched_lock);
}
#else
static inline void
sched_balance_tick(int my_cpu, int idle)
{
}
#endif /* SMP */
static void
kseq_setup(struct kseq *kseq)
{
krunq_init(&kseq->ksq_timeshare[0]);
krunq_init(&kseq->ksq_timeshare[1]);
krunq_init(&kseq->ksq_idle);
kseq->ksq_curr = &kseq->ksq_timeshare[0];
kseq->ksq_next = &kseq->ksq_timeshare[1];
kseq->ksq_best_expired_nice = 21;
#ifdef SMP
TAILQ_INIT(&kseq->ksq_migrateq);
#endif
}
static void
sched_setup(void *dummy)
{
#ifdef SMP
int i;
int t;
#endif
/*
* To avoid divide-by-zero, we set realstathz a dummy value
* in case which sched_clock() called before sched_initticks().
*/
realstathz = hz;
min_timeslice = MAX(5 * hz / 1000, 1);
def_timeslice = MAX(100 * hz / 1000, 1);
granularity = MAX(10 * hz / 1000, 1);
#ifdef SMP
t = ticks;
balance_tick = t;
/*
* Initialize the kseqs.
*/
for (i = 0; i < MAXCPU; i++) {
struct kseq *ksq;
ksq = &kseq_cpu[i];
kseq_setup(&kseq_cpu[i]);
}
if (smp_topology == NULL || ignore_topology) {
struct kseq_group *ksg;
struct kseq *ksq;
int cpus;
for (cpus = 0, i = 0; i < MAXCPU; i++) {
if (CPU_ABSENT(i))
continue;
ksq = &kseq_cpu[i];
ksg = &kseq_groups[cpus];
/*
* Setup a kseq group with one member.
*/
ksq->ksq_group = ksg;
ksg->ksg_cpus = 1;
ksg->ksg_idlemask = 0;
ksg->ksg_cpumask = ksg->ksg_mask = 1 << i;
ksg->ksg_balance_tick = t;
LIST_INIT(&ksg->ksg_members);
LIST_INSERT_HEAD(&ksg->ksg_members, ksq, ksq_siblings);
cpus++;
}
ksg_maxid = cpus - 1;
} else {
struct kseq_group *ksg;
struct cpu_group *cg;
int j;
for (i = 0; i < smp_topology->ct_count; i++) {
cg = &smp_topology->ct_group[i];
ksg = &kseq_groups[i];
/*
* Initialize the group.
*/
ksg->ksg_idlemask = 0;
ksg->ksg_cpus = cg->cg_count;
ksg->ksg_cpumask = cg->cg_mask;
LIST_INIT(&ksg->ksg_members);
/*
* Find all of the group members and add them.
*/
for (j = 0; j < MAXCPU; j++) {
if ((cg->cg_mask & (1 << j)) != 0) {
if (ksg->ksg_mask == 0)
ksg->ksg_mask = 1 << j;
kseq_cpu[j].ksq_group = ksg;
LIST_INSERT_HEAD(&ksg->ksg_members,
&kseq_cpu[j], ksq_siblings);
}
}
ksg->ksg_balance_tick = t;
}
ksg_maxid = smp_topology->ct_count - 1;
}
#else
kseq_setup(KSEQ_SELF());
#endif
mtx_lock_spin(&sched_lock);
kseq_load_add(KSEQ_SELF(), &kse0);
mtx_unlock_spin(&sched_lock);
}
/* ARGSUSED */
static void
sched_initticks(void *dummy)
{
mtx_lock_spin(&sched_lock);
realstathz = stathz ? stathz : hz;
mtx_unlock_spin(&sched_lock);
}
/*
* Very early in the boot some setup of scheduler-specific
* parts of proc0 and of soem scheduler resources needs to be done.
* Called from:
* proc0_init()
*/
void
schedinit(void)
{
/*
* Set up the scheduler specific parts of proc0.
*/
proc0.p_sched = NULL; /* XXX */
ksegrp0.kg_sched = &kg_sched0;
thread0.td_sched = &kse0;
kse0.ke_thread = &thread0;
kse0.ke_state = KES_THREAD;
kse0.ke_slice = 100;
kg_sched0.skg_concurrency = 1;
kg_sched0.skg_avail_opennings = 0; /* we are already running */
}
/*
* This is only somewhat accurate since given many processes of the same
* priority they will switch when their slices run out, which will be
* at most SCHED_SLICE_MAX.
*/
int
sched_rr_interval(void)
{
return (def_timeslice);
}
static void
sched_pctcpu_update(struct kse *ke)
{
/*
* Adjust counters and watermark for pctcpu calc.
*/
if (ke->ke_ltick > ticks - SCHED_CPU_TICKS) {
/*
* Shift the tick count out so that the divide doesn't
* round away our results.
*/
ke->ke_ticks <<= 10;
ke->ke_ticks = (ke->ke_ticks / (ticks - ke->ke_ftick)) *
SCHED_CPU_TICKS;
ke->ke_ticks >>= 10;
} else
ke->ke_ticks = 0;
ke->ke_ltick = ticks;
ke->ke_ftick = ke->ke_ltick - SCHED_CPU_TICKS;
}
void
sched_thread_priority(struct thread *td, u_char prio)
{
struct kse *ke;
ke = td->td_kse;
mtx_assert(&sched_lock, MA_OWNED);
if (__predict_false(td->td_priority == prio))
return;
if (TD_ON_RUNQ(td)) {
/*
* If the priority has been elevated due to priority
* propagation, we may have to move ourselves to a new
* queue. We still call adjustrunqueue below in case kse
* needs to fix things up.
*/
if (prio < td->td_priority && ke->ke_runq != NULL &&
ke->ke_runq != KSEQ_CPU(ke->ke_cpu)->ksq_curr) {
krunq_remove(ke->ke_runq, ke);
ke->ke_runq = KSEQ_CPU(ke->ke_cpu)->ksq_curr;
krunq_add(ke->ke_runq, ke, 0);
}
/*
* Hold this kse on this cpu so that sched_prio() doesn't
* cause excessive migration. We only want migration to
* happen as the result of a wakeup.
*/
ke->ke_flags |= KEF_HOLD;
adjustrunqueue(td, prio);
ke->ke_flags &= ~KEF_HOLD;
} else
td->td_priority = prio;
}
/*
* Update a thread's priority when it is lent another thread's
* priority.
*/
void
sched_lend_prio(struct thread *td, u_char prio)
{
td->td_flags |= TDF_BORROWING;
sched_thread_priority(td, prio);
}
/*
* Restore a thread's priority when priority propagation is
* over. The prio argument is the minimum priority the thread
* needs to have to satisfy other possible priority lending
* requests. If the thread's regular priority is less
* important than prio, the thread will keep a priority boost
* of prio.
*/
void
sched_unlend_prio(struct thread *td, u_char prio)
{
u_char base_pri;
if (td->td_base_pri >= PRI_MIN_TIMESHARE &&
td->td_base_pri <= PRI_MAX_TIMESHARE)
base_pri = td->td_ksegrp->kg_user_pri;
else
base_pri = td->td_base_pri;
if (prio >= base_pri) {
td->td_flags &= ~TDF_BORROWING;
sched_thread_priority(td, base_pri);
} else
sched_lend_prio(td, prio);
}
void
sched_prio(struct thread *td, u_char prio)
{
u_char oldprio;
/* First, update the base priority. */
td->td_base_pri = prio;
/*
* If the thread is borrowing another thread's priority, don't
* ever lower the priority.
*/
if (td->td_flags & TDF_BORROWING && td->td_priority < prio)
return;
/* Change the real priority. */
oldprio = td->td_priority;
sched_thread_priority(td, prio);
/*
* If the thread is on a turnstile, then let the turnstile update
* its state.
*/
if (TD_ON_LOCK(td) && oldprio != prio)
turnstile_adjust(td, oldprio);
}
void
sched_switch(struct thread *td, struct thread *newtd, int flags)
{
struct kseq *ksq;
struct kse *ke;
struct ksegrp *kg;
uint64_t now;
mtx_assert(&sched_lock, MA_OWNED);
now = sched_timestamp();
ke = td->td_kse;
kg = td->td_ksegrp;
ksq = KSEQ_SELF();
td->td_lastcpu = td->td_oncpu;
td->td_oncpu = NOCPU;
td->td_flags &= ~TDF_NEEDRESCHED;
td->td_owepreempt = 0;
/*
* If the KSE has been assigned it may be in the process of switching
* to the new cpu. This is the case in sched_bind().
*/
if (__predict_false(td == PCPU_GET(idlethread))) {
TD_SET_CAN_RUN(td);
} else if (__predict_false((ke->ke_flags & KEF_MIGRATING) != 0)) {
SLOT_RELEASE(td->td_ksegrp);
} else {
/* We are ending our run so make our slot available again */
SLOT_RELEASE(td->td_ksegrp);
kseq_load_rem(ksq, ke);
if (TD_IS_RUNNING(td)) {
/*
* Don't allow the thread to migrate
* from a preemption.
*/
ke->ke_flags |= KEF_HOLD;
setrunqueue(td, (flags & SW_PREEMPT) ?
SRQ_OURSELF|SRQ_YIELDING|SRQ_PREEMPTED :
SRQ_OURSELF|SRQ_YIELDING);
ke->ke_flags &= ~KEF_HOLD;
} else if ((td->td_proc->p_flag & P_HADTHREADS) &&
(newtd == NULL || newtd->td_ksegrp != td->td_ksegrp))
/*
* We will not be on the run queue.
* So we must be sleeping or similar.
* Don't use the slot if we will need it
* for newtd.
*/
slot_fill(td->td_ksegrp);
}
if (newtd != NULL) {
/*
* If we bring in a thread account for it as if it had been
* added to the run queue and then chosen.
*/
newtd->td_kse->ke_flags |= KEF_DIDRUN;
TD_SET_RUNNING(newtd);
kseq_load_add(KSEQ_SELF(), newtd->td_kse);
/*
* XXX When we preempt, we've already consumed a slot because
* we got here through sched_add(). However, newtd can come
* from thread_switchout() which can't SLOT_USE() because
* the SLOT code is scheduler dependent. We must use the
* slot here otherwise.
*/
if ((flags & SW_PREEMPT) == 0)
SLOT_USE(newtd->td_ksegrp);
newtd->td_kse->ke_timestamp = now;
} else
newtd = choosethread();
if (td != newtd) {
sched_update_runtime(ke, now);
ke->ke_lastran = now;
#ifdef HWPMC_HOOKS
if (PMC_PROC_IS_USING_PMCS(td->td_proc))
PMC_SWITCH_CONTEXT(td, PMC_FN_CSW_OUT);
#endif
cpu_switch(td, newtd);
#ifdef HWPMC_HOOKS
if (PMC_PROC_IS_USING_PMCS(td->td_proc))
PMC_SWITCH_CONTEXT(td, PMC_FN_CSW_IN);
#endif
}
sched_lock.mtx_lock = (uintptr_t)td;
td->td_oncpu = PCPU_GET(cpuid);
}
void
sched_nice(struct proc *p, int nice)
{
struct ksegrp *kg;
struct thread *td;
PROC_LOCK_ASSERT(p, MA_OWNED);
mtx_assert(&sched_lock, MA_OWNED);
p->p_nice = nice;
FOREACH_KSEGRP_IN_PROC(p, kg) {
if (kg->kg_pri_class == PRI_TIMESHARE) {
kg->kg_user_pri = sched_calc_pri(kg);
FOREACH_THREAD_IN_GROUP(kg, td)
td->td_flags |= TDF_NEEDRESCHED;
}
}
}
void
sched_sleep(struct thread *td)
{
struct kse *ke;
mtx_assert(&sched_lock, MA_OWNED);
ke = td->td_kse;
if (td->td_flags & TDF_SINTR)
ke->ke_activated = 0;
else
ke->ke_activated = -1;
ke->ke_flags |= KEF_SLEEP;
}
void
sched_wakeup(struct thread *td)
{
struct kse *ke;
struct ksegrp *kg;
struct kseq *kseq, *mykseq;
uint64_t now;
mtx_assert(&sched_lock, MA_OWNED);
ke = td->td_kse;
kg = td->td_ksegrp;
kseq = KSEQ_CPU(ke->ke_cpu);
mykseq = KSEQ_SELF();
if (ke->ke_flags & KEF_SLEEP) {
ke->ke_flags &= ~KEF_SLEEP;
if (sched_is_timeshare(kg)) {
now = sched_timestamp();
sched_commit_runtime(ke);
#ifdef SMP
if (kseq != mykseq)
now = now - mykseq->ksq_last_timestamp +
kseq->ksq_last_timestamp;
#endif
kg->kg_user_pri = sched_recalc_pri(ke, now);
}
}
ke->ke_flags &= ~KEF_NEXTRQ;
setrunqueue(td, SRQ_BORING);
}
/*
* Penalize the parent for creating a new child and initialize the child's
* priority.
*/
void
sched_fork(struct thread *td, struct thread *childtd)
{
mtx_assert(&sched_lock, MA_OWNED);
sched_fork_ksegrp(td, childtd->td_ksegrp);
sched_fork_thread(td, childtd);
}
void
sched_fork_ksegrp(struct thread *td, struct ksegrp *child)
{
struct ksegrp *kg = td->td_ksegrp;
mtx_assert(&sched_lock, MA_OWNED);
child->kg_slptime = kg->kg_slptime * CHILD_WEIGHT / 100;
if (child->kg_pri_class == PRI_TIMESHARE)
child->kg_user_pri = sched_calc_pri(child);
kg->kg_slptime = kg->kg_slptime * PARENT_WEIGHT / 100;
}
void
sched_fork_thread(struct thread *td, struct thread *child)
{
struct kse *ke;
struct kse *ke2;
sched_newthread(child);
ke = td->td_kse;
ke2 = child->td_kse;
#ifdef SMP
ke2->ke_cpu = sched_find_idlest_cpu(ke, PCPU_GET(cpuid));
#else
ke2->ke_cpu = ke->ke_cpu;
#endif
ke2->ke_slice = (ke->ke_slice + 1) >> 1;
ke2->ke_flags |= KEF_FIRST_SLICE;
ke2->ke_activated = 0;
ke2->ke_timestamp = sched_timestamp();
ke->ke_slice >>= 1;
if (ke->ke_slice == 0) {
ke->ke_slice = 1;
sched_tick();
}
/* Grab our parents cpu estimation information. */
ke2->ke_ticks = ke->ke_ticks;
ke2->ke_ltick = ke->ke_ltick;
ke2->ke_ftick = ke->ke_ftick;
}
void
sched_class(struct ksegrp *kg, int class)
{
struct kseq *kseq;
struct kse *ke;
struct thread *td;
int nclass;
int oclass;
mtx_assert(&sched_lock, MA_OWNED);
if (kg->kg_pri_class == class)
return;
nclass = PRI_BASE(class);
oclass = PRI_BASE(kg->kg_pri_class);
FOREACH_THREAD_IN_GROUP(kg, td) {
ke = td->td_kse;
/* New thread does not have runq assigned */
if (ke->ke_runq == NULL)
continue;
kseq = KSEQ_CPU(ke->ke_cpu);
if (oclass == PRI_TIMESHARE)
kseq->ksq_load_timeshare--;
else if (oclass == PRI_IDLE)
kseq->ksq_load_idle--;
if (nclass == PRI_TIMESHARE)
kseq->ksq_load_timeshare++;
else if (nclass == PRI_IDLE)
kseq->ksq_load_idle++;
}
kg->kg_pri_class = class;
}
/*
* Return some of the child's priority and interactivity to the parent.
*/
void
sched_exit(struct proc *p, struct thread *childtd)
{
mtx_assert(&sched_lock, MA_OWNED);
sched_exit_thread(FIRST_THREAD_IN_PROC(p), childtd);
sched_exit_ksegrp(FIRST_KSEGRP_IN_PROC(p), childtd);
}
void
sched_exit_ksegrp(struct ksegrp *parentkg, struct thread *td)
{
if (td->td_ksegrp->kg_slptime < parentkg->kg_slptime) {
parentkg->kg_slptime = parentkg->kg_slptime /
(EXIT_WEIGHT) * (EXIT_WEIGHT - 1) +
td->td_ksegrp->kg_slptime / EXIT_WEIGHT;
}
}
void
sched_exit_thread(struct thread *td, struct thread *childtd)
{
struct kse *childke = childtd->td_kse;
struct kse *parentke = td->td_kse;
kseq_load_rem(KSEQ_CPU(childke->ke_cpu), childke);
sched_update_runtime(childke, sched_timestamp());
sched_commit_runtime(childke);
if ((childke->ke_flags & KEF_FIRST_SLICE) &&
td->td_proc == childtd->td_proc->p_pptr) {
parentke->ke_slice += childke->ke_slice;
if (parentke->ke_slice > sched_timeslice(parentke))
parentke->ke_slice = sched_timeslice(parentke);
}
}
static int
sched_starving(struct kseq *ksq, uint64_t now, struct kse *ke)
{
uint64_t delta;
if (PROC_NICE(ke->ke_proc) > ksq->ksq_best_expired_nice)
return (1);
if (ksq->ksq_expired_timestamp == 0)
return (0);
delta = now - ksq->ksq_expired_timestamp;
if (delta > STARVATION_TIME * (ksq->ksq_load - ksq->ksq_load_idle))
return (1);
return (0);
}
/*
* An interactive thread has smaller time slice granularity,
* a cpu hog can have larger granularity.
*/
static inline int
sched_timeslice_split(struct kse *ke)
{
int score, g;
score = (int)(MAX_SCORE - CURRENT_SCORE(ke->ke_ksegrp));
if (score == 0)
score = 1;
#ifdef SMP
g = granularity * ((1 << score) - 1) * smp_cpus;
#else
g = granularity * ((1 << score) - 1);
#endif
return (ke->ke_slice >= g && ke->ke_slice % g == 0);
}
void
sched_tick(void)
{
struct thread *td;
struct proc *p;
struct kse *ke;
struct ksegrp *kg;
struct kseq *kseq;
uint64_t now;
int cpuid;
int class;
mtx_assert(&sched_lock, MA_OWNED);
td = curthread;
ke = td->td_kse;
kg = ke->ke_ksegrp;
p = ke->ke_proc;
class = PRI_BASE(kg->kg_pri_class);
now = sched_timestamp();
cpuid = PCPU_GET(cpuid);
kseq = KSEQ_CPU(cpuid);
kseq->ksq_last_timestamp = now;
if (class == PRI_IDLE) {
int idle_td = (curthread == PCPU_GET(idlethread));
/*
* Processes of equal idle priority are run round-robin.
*/
if (!idle_td && --ke->ke_slice <= 0) {
ke->ke_slice = def_timeslice;
td->td_flags |= TDF_NEEDRESCHED;
}
sched_balance_tick(cpuid, idle_td ? IDLE_IDLE : IDLE);
return;
}
if (ke->ke_flags & KEF_NEXTRQ) {
/* The thread was already scheduled off. */
curthread->td_flags |= TDF_NEEDRESCHED;
goto out;
}
if (class == PRI_REALTIME) {
/*
* Realtime scheduling, do round robin for RR class, FIFO
* is not affected.
*/
if (PRI_NEED_RR(kg->kg_pri_class) && --ke->ke_slice <= 0) {
ke->ke_slice = def_timeslice;
curthread->td_flags |= TDF_NEEDRESCHED;
}
goto out;
}
/*
* Current, we skip kernel thread, though it may be classified as
* TIMESHARE.
*/
if (class != PRI_TIMESHARE || (p->p_flag & P_KTHREAD) != 0)
goto out;
if (--ke->ke_slice <= 0) {
curthread->td_flags |= TDF_NEEDRESCHED;
sched_update_runtime(ke, now);
sched_commit_runtime(ke);
kg->kg_user_pri = sched_calc_pri(kg);
ke->ke_slice = sched_timeslice(ke);
ke->ke_flags &= ~KEF_FIRST_SLICE;
if (!kseq->ksq_expired_timestamp)
kseq->ksq_expired_timestamp = now;
if (!THREAD_IS_INTERACTIVE(ke) ||
sched_starving(kseq, now, ke)) {
/* The thead becomes cpu hog, schedule it off. */
ke->ke_flags |= KEF_NEXTRQ;
if (PROC_NICE(p) < kseq->ksq_best_expired_nice)
kseq->ksq_best_expired_nice = PROC_NICE(p);
}
} else {
/*
* Don't allow an interactive thread which has long timeslice
* to monopolize CPU, split the long timeslice into small
* chunks. This essentially does round-robin between
* interactive threads.
*/
if (THREAD_IS_INTERACTIVE(ke) && sched_timeslice_split(ke))
curthread->td_flags |= TDF_NEEDRESCHED;
}
out:
sched_balance_tick(cpuid, NOT_IDLE);
}
void
sched_clock(struct thread *td)
{
struct ksegrp *kg;
struct kse *ke;
mtx_assert(&sched_lock, MA_OWNED);
ke = td->td_kse;
kg = ke->ke_ksegrp;
/* Adjust ticks for pctcpu */
ke->ke_ticks++;
ke->ke_ltick = ticks;
/* Go up to one second beyond our max and then trim back down */
if (ke->ke_ftick + SCHED_CPU_TICKS + hz < ke->ke_ltick)
sched_pctcpu_update(ke);
}
int
sched_runnable(void)
{
struct kseq *kseq;
kseq = KSEQ_SELF();
if (krunq_findbit(kseq->ksq_curr) != -1 ||
krunq_findbit(kseq->ksq_next) != -1 ||
krunq_findbit(&kseq->ksq_idle) != -1)
return (1);
return (0);
}
void
sched_userret(struct thread *td)
{
struct ksegrp *kg;
KASSERT((td->td_flags & TDF_BORROWING) == 0,
("thread with borrowed priority returning to userland"));
kg = td->td_ksegrp;
if (td->td_priority != kg->kg_user_pri) {
mtx_lock_spin(&sched_lock);
td->td_priority = kg->kg_user_pri;
td->td_base_pri = kg->kg_user_pri;
mtx_unlock_spin(&sched_lock);
}
}
struct kse *
sched_choose(void)
{
struct kseq *kseq;
struct kse *ke;
mtx_assert(&sched_lock, MA_OWNED);
kseq = KSEQ_SELF();
#ifdef SMP
restart:
#endif
ke = kseq_choose(kseq);
if (ke) {
#ifdef SMP
if (ke->ke_ksegrp->kg_pri_class == PRI_IDLE)
if (sched_idled(kseq, IDLE) == 0)
goto restart;
#endif
kseq_runq_rem(kseq, ke);
ke->ke_state = KES_THREAD;
ke->ke_flags &= ~KEF_PREEMPTED;
ke->ke_timestamp = sched_timestamp();
return (ke);
}
#ifdef SMP
if (sched_idled(kseq, IDLE_IDLE) == 0)
goto restart;
#endif
return (NULL);
}
void
sched_add(struct thread *td, int flags)
{
struct kseq *ksq, *my_ksq;
struct ksegrp *kg;
struct kse *ke;
int preemptive;
int canmigrate;
int class;
int my_cpu;
int nextrq;
#ifdef SMP
struct thread *td2;
struct pcpu *pcpu;
int cpu, new_cpu;
int load, my_load;
#endif
mtx_assert(&sched_lock, MA_OWNED);
ke = td->td_kse;
kg = td->td_ksegrp;
KASSERT(ke->ke_state != KES_ONRUNQ,
("sched_add: kse %p (%s) already in run queue", ke,
ke->ke_proc->p_comm));
KASSERT(ke->ke_proc->p_sflag & PS_INMEM,
("sched_add: process swapped out"));
KASSERT(ke->ke_runq == NULL,
("sched_add: KSE %p is still assigned to a run queue", ke));
canmigrate = 1;
preemptive = !(flags & SRQ_YIELDING);
class = PRI_BASE(kg->kg_pri_class);
my_cpu = PCPU_GET(cpuid);
my_ksq = KSEQ_CPU(my_cpu);
if (flags & SRQ_PREEMPTED)
ke->ke_flags |= KEF_PREEMPTED;
if ((ke->ke_flags & KEF_INTERNAL) == 0)
SLOT_USE(td->td_ksegrp);
nextrq = (ke->ke_flags & KEF_NEXTRQ);
ke->ke_flags &= ~(KEF_NEXTRQ | KEF_INTERNAL);
#ifdef SMP
cpu = ke->ke_cpu;
canmigrate = kse_can_migrate(ke);
/*
* Don't migrate running threads here. Force the long term balancer
* to do it.
*/
if (ke->ke_flags & KEF_HOLD) {
ke->ke_flags &= ~KEF_HOLD;
canmigrate = 0;
}
/*
* If this thread is pinned or bound, notify the target cpu.
*/
if (!canmigrate)
goto activate_it;
if (class == PRI_ITHD) {
ke->ke_cpu = my_cpu;
goto activate_it;
}
if (ke->ke_cpu == my_cpu)
goto activate_it;
if (my_ksq->ksq_group->ksg_idlemask & PCPU_GET(cpumask)) {
ke->ke_cpu = my_cpu;
goto activate_it;
}
new_cpu = my_cpu;
load = kseq_source_load(KSEQ_CPU(cpu));
my_load = kseq_dest_load(my_ksq);
if ((my_load - load) * 100 < my_load * imbalance_pct2)
goto try_idle_cpu;
new_cpu = cpu;
try_idle_cpu:
new_cpu = sched_find_idle_cpu(new_cpu);
ke->ke_cpu = new_cpu;
activate_it:
if (ke->ke_cpu != cpu)
ke->ke_lastran = 0;
#endif
ksq = KSEQ_CPU(ke->ke_cpu);
switch (class) {
case PRI_ITHD:
case PRI_REALTIME:
ke->ke_runq = ksq->ksq_curr;
break;
case PRI_TIMESHARE:
if ((td->td_flags & TDF_BORROWING) == 0 && nextrq)
ke->ke_runq = ksq->ksq_next;
else
ke->ke_runq = ksq->ksq_curr;
break;
case PRI_IDLE:
/*
* This is for priority prop.
*/
if (td->td_priority < PRI_MIN_IDLE)
ke->ke_runq = ksq->ksq_curr;
else
ke->ke_runq = &ksq->ksq_idle;
break;
default:
panic("Unknown pri class.");
break;
}
if (ke->ke_runq == my_ksq->ksq_curr &&
td->td_priority < curthread->td_priority) {
curthread->td_flags |= TDF_NEEDRESCHED;
ke->ke_runq = NULL;
if (preemptive && maybe_preempt(td))
return;
ke->ke_runq = my_ksq->ksq_curr;
if (curthread->td_ksegrp->kg_pri_class == PRI_IDLE)
td->td_owepreempt = 1;
}
ke->ke_state = KES_ONRUNQ;
kseq_runq_add(ksq, ke, flags);
kseq_load_add(ksq, ke);
#ifdef SMP
pcpu = pcpu_find(ke->ke_cpu);
if (class != PRI_IDLE) {
if (kseq_idle & ksq->ksq_group->ksg_mask)
kseq_idle &= ~ksq->ksq_group->ksg_mask;
if (ksq->ksq_group->ksg_idlemask & pcpu->pc_cpumask)
ksq->ksq_group->ksg_idlemask &= ~pcpu->pc_cpumask;
}
if (ke->ke_cpu != my_cpu) {
td2 = pcpu->pc_curthread;
if (__predict_false(td2 == pcpu->pc_idlethread)) {
td2->td_flags |= TDF_NEEDRESCHED;
ipi_selected(pcpu->pc_cpumask, IPI_AST);
} else if (td->td_priority < td2->td_priority) {
if (class == PRI_ITHD || class == PRI_REALTIME ||
td2->td_ksegrp->kg_pri_class == PRI_IDLE)
ipi_selected(pcpu->pc_cpumask, IPI_PREEMPT);
else if ((td2->td_flags & TDF_NEEDRESCHED) == 0) {
td2->td_flags |= TDF_NEEDRESCHED;
ipi_selected(pcpu->pc_cpumask, IPI_AST);
}
}
}
#endif
}
void
sched_rem(struct thread *td)
{
struct kseq *kseq;
struct kse *ke;
mtx_assert(&sched_lock, MA_OWNED);
ke = td->td_kse;
ke->ke_flags &= ~KEF_PREEMPTED;
KASSERT((ke->ke_state == KES_ONRUNQ),
("sched_rem: KSE not on run queue"));
kseq = KSEQ_CPU(ke->ke_cpu);
#ifdef SMP
if (ke->ke_flags & KEF_MIGRATING) {
ke->ke_flags &= ~KEF_MIGRATING;
kseq_load_rem(kseq, ke);
TAILQ_REMOVE(&kseq->ksq_migrateq, ke, ke_procq);
ke->ke_cpu = ke->ke_tocpu;
} else
#endif
{
KASSERT((ke->ke_state == KES_ONRUNQ),
("sched_rem: KSE not on run queue"));
SLOT_RELEASE(td->td_ksegrp);
kseq_runq_rem(kseq, ke);
kseq_load_rem(kseq, ke);
}
ke->ke_state = KES_THREAD;
}
fixpt_t
sched_pctcpu(struct thread *td)
{
fixpt_t pctcpu;
struct kse *ke;
pctcpu = 0;
ke = td->td_kse;
if (ke == NULL)
return (0);
mtx_lock_spin(&sched_lock);
if (ke->ke_ticks) {
int rtick;
/*
* Don't update more frequently than twice a second. Allowing
* this causes the cpu usage to decay away too quickly due to
* rounding errors.
*/
if (ke->ke_ftick + SCHED_CPU_TICKS < ke->ke_ltick ||
ke->ke_ltick < (ticks - (hz / 2)))
sched_pctcpu_update(ke);
/* How many rtick per second ? */
rtick = MIN(ke->ke_ticks / SCHED_CPU_TIME, SCHED_CPU_TICKS);
pctcpu = (FSCALE * ((FSCALE * rtick)/realstathz)) >> FSHIFT;
}
ke->ke_proc->p_swtime = ke->ke_ltick - ke->ke_ftick;
mtx_unlock_spin(&sched_lock);
return (pctcpu);
}
void
sched_bind(struct thread *td, int cpu)
{
struct kseq *kseq;
struct kse *ke;
mtx_assert(&sched_lock, MA_OWNED);
ke = td->td_kse;
ke->ke_flags |= KEF_BOUND;
#ifdef SMP
if (PCPU_GET(cpuid) == cpu)
return;
kseq = KSEQ_SELF();
ke->ke_flags |= KEF_MIGRATING;
ke->ke_tocpu = cpu;
TAILQ_INSERT_TAIL(&kseq->ksq_migrateq, ke, ke_procq);
if (kseq->ksq_migrated) {
if (TD_AWAITING_INTR(kseq->ksq_migrated)) {
TD_CLR_IWAIT(kseq->ksq_migrated);
setrunqueue(kseq->ksq_migrated, SRQ_YIELDING);
}
}
/* When we return from mi_switch we'll be on the correct cpu. */
mi_switch(SW_VOL, NULL);
#else
(void)kseq;
#endif
}
void
sched_unbind(struct thread *td)
{
mtx_assert(&sched_lock, MA_OWNED);
td->td_kse->ke_flags &= ~KEF_BOUND;
}
int
sched_is_bound(struct thread *td)
{
mtx_assert(&sched_lock, MA_OWNED);
return (td->td_kse->ke_flags & KEF_BOUND);
}
int
sched_load(void)
{
#ifdef SMP
int total;
int i;
total = 0;
for (i = 0; i < MAXCPU; i++)
total += KSEQ_CPU(i)->ksq_sysload;
return (total);
#else
return (KSEQ_SELF()->ksq_sysload);
#endif
}
void
sched_relinquish(struct thread *td)
{
struct ksegrp *kg;
kg = td->td_ksegrp;
mtx_lock_spin(&sched_lock);
if (sched_is_timeshare(kg)) {
sched_prio(td, PRI_MAX_TIMESHARE);
td->td_kse->ke_flags |= KEF_NEXTRQ;
}
mi_switch(SW_VOL, NULL);
mtx_unlock_spin(&sched_lock);
}
int
sched_sizeof_ksegrp(void)
{
return (sizeof(struct ksegrp) + sizeof(struct kg_sched));
}
int
sched_sizeof_proc(void)
{
return (sizeof(struct proc));
}
int
sched_sizeof_thread(void)
{
return (sizeof(struct thread) + sizeof(struct td_sched));
}
#define KERN_SWITCH_INCLUDE 1
#include "kern/kern_switch.c"
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