Commit 99e97b86 authored by Linus Torvalds's avatar Linus Torvalds

Merge branch 'sched-core-for-linus' of...

Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  sched: fix typo in sched-rt-group.txt file
  ftrace: fix typo about map of kernel priority in ftrace.txt file.
  sched: properly define the sched_group::cpumask and sched_domain::span fields
  sched, timers: cleanup avenrun users
  sched, timers: move calc_load() to scheduler
  sched: Don't export sched_mc_power_savings on multi-socket single core system
  sched: emit thread info flags with stack trace
  sched: rt: document the risk of small values in the bandwidth settings
  sched: Replace first_cpu() with cpumask_first() in ILB nomination code
  sched: remove extra call overhead for schedule()
  sched: use group_first_cpu() instead of cpumask_first(sched_group_cpus())
  wait: don't use __wake_up_common()
  sched: Nominate a power-efficient ilb in select_nohz_balancer()
  sched: Nominate idle load balancer from a semi-idle package.
  sched: remove redundant hierarchy walk in check_preempt_wakeup
parents 82782ca7 f04d82b7
......@@ -4,6 +4,7 @@
CONTENTS
========
0. WARNING
1. Overview
1.1 The problem
1.2 The solution
......@@ -14,6 +15,23 @@ CONTENTS
3. Future plans
0. WARNING
==========
Fiddling with these settings can result in an unstable system, the knobs are
root only and assumes root knows what he is doing.
Most notable:
* very small values in sched_rt_period_us can result in an unstable
system when the period is smaller than either the available hrtimer
resolution, or the time it takes to handle the budget refresh itself.
* very small values in sched_rt_runtime_us can result in an unstable
system when the runtime is so small the system has difficulty making
forward progress (NOTE: the migration thread and kstopmachine both
are real-time processes).
1. Overview
===========
......@@ -169,7 +187,7 @@ get their allocated time.
Implementing SCHED_EDF might take a while to complete. Priority Inheritance is
the biggest challenge as the current linux PI infrastructure is geared towards
the limited static priority levels 0-139. With deadline scheduling you need to
the limited static priority levels 0-99. With deadline scheduling you need to
do deadline inheritance (since priority is inversely proportional to the
deadline delta (deadline - now).
......
......@@ -518,9 +518,18 @@ priority with zero (0) being the highest priority and the nice
values starting at 100 (nice -20). Below is a quick chart to map
the kernel priority to user land priorities.
Kernel priority: 0 to 99 ==> user RT priority 99 to 0
Kernel priority: 100 to 139 ==> user nice -20 to 19
Kernel priority: 140 ==> idle task priority
Kernel Space User Space
===============================================================
0(high) to 98(low) user RT priority 99(high) to 1(low)
with SCHED_RR or SCHED_FIFO
---------------------------------------------------------------
99 sched_priority is not used in scheduling
decisions(it must be specified as 0)
---------------------------------------------------------------
100(high) to 139(low) user nice -20(high) to 19(low)
---------------------------------------------------------------
140 idle task priority
---------------------------------------------------------------
The task states are:
......
......@@ -203,7 +203,8 @@ struct pci_bus;
void x86_pci_root_bus_res_quirks(struct pci_bus *b);
#ifdef CONFIG_SMP
#define mc_capable() (cpumask_weight(cpu_core_mask(0)) != nr_cpu_ids)
#define mc_capable() ((boot_cpu_data.x86_max_cores > 1) && \
(cpumask_weight(cpu_core_mask(0)) != nr_cpu_ids))
#define smt_capable() (smp_num_siblings > 1)
#endif
......
......@@ -12,20 +12,14 @@
static int loadavg_proc_show(struct seq_file *m, void *v)
{
int a, b, c;
unsigned long seq;
unsigned long avnrun[3];
do {
seq = read_seqbegin(&xtime_lock);
a = avenrun[0] + (FIXED_1/200);
b = avenrun[1] + (FIXED_1/200);
c = avenrun[2] + (FIXED_1/200);
} while (read_seqretry(&xtime_lock, seq));
get_avenrun(avnrun, FIXED_1/200, 0);
seq_printf(m, "%d.%02d %d.%02d %d.%02d %ld/%d %d\n",
LOAD_INT(a), LOAD_FRAC(a),
LOAD_INT(b), LOAD_FRAC(b),
LOAD_INT(c), LOAD_FRAC(c),
seq_printf(m, "%lu.%02lu %lu.%02lu %lu.%02lu %ld/%d %d\n",
LOAD_INT(avnrun[0]), LOAD_FRAC(avnrun[0]),
LOAD_INT(avnrun[1]), LOAD_FRAC(avnrun[1]),
LOAD_INT(avnrun[2]), LOAD_FRAC(avnrun[2]),
nr_running(), nr_threads,
task_active_pid_ns(current)->last_pid);
return 0;
......
......@@ -116,6 +116,7 @@ struct fs_struct;
* 11 bit fractions.
*/
extern unsigned long avenrun[]; /* Load averages */
extern void get_avenrun(unsigned long *loads, unsigned long offset, int shift);
#define FSHIFT 11 /* nr of bits of precision */
#define FIXED_1 (1<<FSHIFT) /* 1.0 as fixed-point */
......@@ -135,8 +136,8 @@ DECLARE_PER_CPU(unsigned long, process_counts);
extern int nr_processes(void);
extern unsigned long nr_running(void);
extern unsigned long nr_uninterruptible(void);
extern unsigned long nr_active(void);
extern unsigned long nr_iowait(void);
extern void calc_global_load(void);
extern unsigned long get_parent_ip(unsigned long addr);
......@@ -838,7 +839,17 @@ struct sched_group {
*/
u32 reciprocal_cpu_power;
unsigned long cpumask[];
/*
* The CPUs this group covers.
*
* NOTE: this field is variable length. (Allocated dynamically
* by attaching extra space to the end of the structure,
* depending on how many CPUs the kernel has booted up with)
*
* It is also be embedded into static data structures at build
* time. (See 'struct static_sched_group' in kernel/sched.c)
*/
unsigned long cpumask[0];
};
static inline struct cpumask *sched_group_cpus(struct sched_group *sg)
......@@ -924,8 +935,17 @@ struct sched_domain {
char *name;
#endif
/* span of all CPUs in this domain */
unsigned long span[];
/*
* Span of all CPUs in this domain.
*
* NOTE: this field is variable length. (Allocated dynamically
* by attaching extra space to the end of the structure,
* depending on how many CPUs the kernel has booted up with)
*
* It is also be embedded into static data structures at build
* time. (See 'struct static_sched_domain' in kernel/sched.c)
*/
unsigned long span[0];
};
static inline struct cpumask *sched_domain_span(struct sched_domain *sd)
......
......@@ -132,8 +132,6 @@ static inline void __remove_wait_queue(wait_queue_head_t *head,
list_del(&old->task_list);
}
void __wake_up_common(wait_queue_head_t *q, unsigned int mode,
int nr_exclusive, int sync, void *key);
void __wake_up(wait_queue_head_t *q, unsigned int mode, int nr, void *key);
void __wake_up_locked_key(wait_queue_head_t *q, unsigned int mode, void *key);
void __wake_up_sync_key(wait_queue_head_t *q, unsigned int mode, int nr,
......
......@@ -249,7 +249,9 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
/* didnt get the lock, go to sleep: */
spin_unlock_mutex(&lock->wait_lock, flags);
__schedule();
preempt_enable_no_resched();
schedule();
preempt_disable();
spin_lock_mutex(&lock->wait_lock, flags);
}
......
This diff is collapsed.
......@@ -1487,17 +1487,10 @@ static void check_preempt_wakeup(struct rq *rq, struct task_struct *p, int sync)
find_matching_se(&se, &pse);
while (se) {
BUG_ON(!pse);
if (wakeup_preempt_entity(se, pse) == 1) {
if (wakeup_preempt_entity(se, pse) == 1)
resched_task(curr);
break;
}
se = parent_entity(se);
pse = parent_entity(pse);
}
}
static struct task_struct *pick_next_task_fair(struct rq *rq)
......
......@@ -22,7 +22,8 @@ static void check_preempt_curr_idle(struct rq *rq, struct task_struct *p, int sy
static struct task_struct *pick_next_task_idle(struct rq *rq)
{
schedstat_inc(rq, sched_goidle);
/* adjust the active tasks as we might go into a long sleep */
calc_load_account_active(rq);
return rq->idle;
}
......
......@@ -22,7 +22,7 @@
/*
* This read-write spinlock protects us from races in SMP while
* playing with xtime and avenrun.
* playing with xtime.
*/
__cacheline_aligned_in_smp DEFINE_SEQLOCK(xtime_lock);
......
......@@ -1122,47 +1122,6 @@ void update_process_times(int user_tick)
run_posix_cpu_timers(p);
}
/*
* Nr of active tasks - counted in fixed-point numbers
*/
static unsigned long count_active_tasks(void)
{
return nr_active() * FIXED_1;
}
/*
* Hmm.. Changed this, as the GNU make sources (load.c) seems to
* imply that avenrun[] is the standard name for this kind of thing.
* Nothing else seems to be standardized: the fractional size etc
* all seem to differ on different machines.
*
* Requires xtime_lock to access.
*/
unsigned long avenrun[3];
EXPORT_SYMBOL(avenrun);
/*
* calc_load - given tick count, update the avenrun load estimates.
* This is called while holding a write_lock on xtime_lock.
*/
static inline void calc_load(unsigned long ticks)
{
unsigned long active_tasks; /* fixed-point */
static int count = LOAD_FREQ;
count -= ticks;
if (unlikely(count < 0)) {
active_tasks = count_active_tasks();
do {
CALC_LOAD(avenrun[0], EXP_1, active_tasks);
CALC_LOAD(avenrun[1], EXP_5, active_tasks);
CALC_LOAD(avenrun[2], EXP_15, active_tasks);
count += LOAD_FREQ;
} while (count < 0);
}
}
/*
* This function runs timers and the timer-tq in bottom half context.
*/
......@@ -1186,16 +1145,6 @@ void run_local_timers(void)
softlockup_tick();
}
/*
* Called by the timer interrupt. xtime_lock must already be taken
* by the timer IRQ!
*/
static inline void update_times(unsigned long ticks)
{
update_wall_time();
calc_load(ticks);
}
/*
* The 64-bit jiffies value is not atomic - you MUST NOT read it
* without sampling the sequence number in xtime_lock.
......@@ -1205,7 +1154,8 @@ static inline void update_times(unsigned long ticks)
void do_timer(unsigned long ticks)
{
jiffies_64 += ticks;
update_times(ticks);
update_wall_time();
calc_global_load();
}
#ifdef __ARCH_WANT_SYS_ALARM
......@@ -1406,37 +1356,17 @@ int do_sysinfo(struct sysinfo *info)
{
unsigned long mem_total, sav_total;
unsigned int mem_unit, bitcount;
unsigned long seq;
memset(info, 0, sizeof(struct sysinfo));
do {
struct timespec tp;
seq = read_seqbegin(&xtime_lock);
/*
* This is annoying. The below is the same thing
* posix_get_clock_monotonic() does, but it wants to
* take the lock which we want to cover the loads stuff
* too.
*/
memset(info, 0, sizeof(struct sysinfo));
getnstimeofday(&tp);
tp.tv_sec += wall_to_monotonic.tv_sec;
tp.tv_nsec += wall_to_monotonic.tv_nsec;
ktime_get_ts(&tp);
monotonic_to_bootbased(&tp);
if (tp.tv_nsec - NSEC_PER_SEC >= 0) {
tp.tv_nsec = tp.tv_nsec - NSEC_PER_SEC;
tp.tv_sec++;
}
info->uptime = tp.tv_sec + (tp.tv_nsec ? 1 : 0);
info->loads[0] = avenrun[0] << (SI_LOAD_SHIFT - FSHIFT);
info->loads[1] = avenrun[1] << (SI_LOAD_SHIFT - FSHIFT);
info->loads[2] = avenrun[2] << (SI_LOAD_SHIFT - FSHIFT);
get_avenrun(info->loads, 0, SI_LOAD_SHIFT - FSHIFT);
info->procs = nr_threads;
} while (read_seqretry(&xtime_lock, seq));
si_meminfo(info);
si_swapinfo(info);
......
......@@ -154,7 +154,7 @@ void abort_exclusive_wait(wait_queue_head_t *q, wait_queue_t *wait,
if (!list_empty(&wait->task_list))
list_del_init(&wait->task_list);
else if (waitqueue_active(q))
__wake_up_common(q, mode, 1, 0, key);
__wake_up_locked_key(q, mode, key);
spin_unlock_irqrestore(&q->lock, flags);
}
EXPORT_SYMBOL(abort_exclusive_wait);
......
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