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Commit 831576fe authored by Linus Torvalds's avatar Linus Torvalds
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Merge branch 'sched-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 

* 'sched-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (46 commits)
  sched: Add comments to find_busiest_group() function
  sched: Refactor the power savings balance code
  sched: Optimize the !power_savings_balance during fbg()
  sched: Create a helper function to calculate imbalance
  sched: Create helper to calculate small_imbalance in fbg()
  sched: Create a helper function to calculate sched_domain stats for fbg()
  sched: Define structure to store the sched_domain statistics for fbg()
  sched: Create a helper function to calculate sched_group stats for fbg()
  sched: Define structure to store the sched_group statistics for fbg()
  sched: Fix indentations in find_busiest_group() using gotos
  sched: Simple helper functions for find_busiest_group()
  sched: remove unused fields from struct rq
  sched: jiffies not printed per CPU
  sched: small optimisation of can_migrate_task()
  sched: fix typos in documentation
  sched: add avg_overlap decay
  x86, sched_clock(): mark variables read-mostly
  sched: optimize ttwu vs group scheduling
  sched: TIF_NEED_RESCHED -> need_reshed() cleanup
  sched: don't rebalance if attached on NULL domain
  ...
parents 21cdbc13 66fef08f
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Documentation/scheduler/00-INDEX
View file @ 831576fe
......@@ -2,8 +2,6 @@
- this file.
sched-arch.txt
- CPU Scheduler implementation hints for architecture specific code.
sched-coding.txt
- reference for various scheduler-related methods in the O(1) scheduler.
sched-design-CFS.txt
- goals, design and implementation of the Complete Fair Scheduler.
sched-domains.txt
......
Documentation/scheduler/sched-coding.txt deleted 100644 → 0
View file @ 21cdbc13
Reference for various scheduler-related methods in the O(1) scheduler
Robert Love <rml@tech9.net>, MontaVista Software
Note most of these methods are local to kernel/sched.c - this is by design.
The scheduler is meant to be self-contained and abstracted away. This document
is primarily for understanding the scheduler, not interfacing to it. Some of
the discussed interfaces, however, are general process/scheduling methods.
They are typically defined in include/linux/sched.h.
Main Scheduling Methods
-----------------------
void load_balance(runqueue_t *this_rq, int idle)
Attempts to pull tasks from one cpu to another to balance cpu usage,
if needed. This method is called explicitly if the runqueues are
imbalanced or periodically by the timer tick. Prior to calling,
the current runqueue must be locked and interrupts disabled.
void schedule()
The main scheduling function. Upon return, the highest priority
process will be active.
Locking
-------
Each runqueue has its own lock, rq->lock. When multiple runqueues need
to be locked, lock acquires must be ordered by ascending &runqueue value.
A specific runqueue is locked via
task_rq_lock(task_t pid, unsigned long *flags)
which disables preemption, disables interrupts, and locks the runqueue pid is
running on. Likewise,
task_rq_unlock(task_t pid, unsigned long *flags)
unlocks the runqueue pid is running on, restores interrupts to their previous
state, and reenables preemption.
The routines
double_rq_lock(runqueue_t *rq1, runqueue_t *rq2)
and
double_rq_unlock(runqueue_t *rq1, runqueue_t *rq2)
safely lock and unlock, respectively, the two specified runqueues. They do
not, however, disable and restore interrupts. Users are required to do so
manually before and after calls.
Values
------
MAX_PRIO
The maximum priority of the system, stored in the task as task->prio.
Lower priorities are higher. Normal (non-RT) priorities range from
MAX_RT_PRIO to (MAX_PRIO - 1).
MAX_RT_PRIO
The maximum real-time priority of the system. Valid RT priorities
range from 0 to (MAX_RT_PRIO - 1).
MAX_USER_RT_PRIO
The maximum real-time priority that is exported to user-space. Should
always be equal to or less than MAX_RT_PRIO. Setting it less allows
kernel threads to have higher priorities than any user-space task.
MIN_TIMESLICE
MAX_TIMESLICE
Respectively, the minimum and maximum timeslices (quanta) of a process.
Data
----
struct runqueue
The main per-CPU runqueue data structure.
struct task_struct
The main per-process data structure.
General Methods
---------------
cpu_rq(cpu)
Returns the runqueue of the specified cpu.
this_rq()
Returns the runqueue of the current cpu.
task_rq(pid)
Returns the runqueue which holds the specified pid.
cpu_curr(cpu)
Returns the task currently running on the given cpu.
rt_task(pid)
Returns true if pid is real-time, false if not.
Process Control Methods
-----------------------
void set_user_nice(task_t *p, long nice)
Sets the "nice" value of task p to the given value.
int setscheduler(pid_t pid, int policy, struct sched_param *param)
Sets the scheduling policy and parameters for the given pid.
int set_cpus_allowed(task_t *p, unsigned long new_mask)
Sets a given task's CPU affinity and migrates it to a proper cpu.
Callers must have a valid reference to the task and assure the
task not exit prematurely. No locks can be held during the call.
set_task_state(tsk, state_value)
Sets the given task's state to the given value.
set_current_state(state_value)
Sets the current task's state to the given value.
void set_tsk_need_resched(struct task_struct *tsk)
Sets need_resched in the given task.
void clear_tsk_need_resched(struct task_struct *tsk)
Clears need_resched in the given task.
void set_need_resched()
Sets need_resched in the current task.
void clear_need_resched()
Clears need_resched in the current task.
int need_resched()
Returns true if need_resched is set in the current task, false
otherwise.
yield()
Place the current process at the end of the runqueue and call schedule.
arch/x86/kernel/cpu/intel.c
View file @ 831576fe
......@@ -4,6 +4,7 @@
#include <linux/string.h>
#include <linux/bitops.h>
#include <linux/smp.h>
#include <linux/sched.h>
#include <linux/thread_info.h>
#include <linux/module.h>
......@@ -56,11 +57,16 @@ static void __cpuinit early_init_intel(struct cpuinfo_x86 *c)
/*
* c->x86_power is 8000_0007 edx. Bit 8 is TSC runs at constant rate
* with P/T states and does not stop in deep C-states
* with P/T states and does not stop in deep C-states.
*
* It is also reliable across cores and sockets. (but not across
* cabinets - we turn it off in that case explicitly.)
*/
if (c->x86_power & (1 << 8)) {
set_cpu_cap(c, X86_FEATURE_CONSTANT_TSC);
set_cpu_cap(c, X86_FEATURE_NONSTOP_TSC);
set_cpu_cap(c, X86_FEATURE_TSC_RELIABLE);
sched_clock_stable = 1;
}
}
......
arch/x86/kernel/tsc.c
View file @ 831576fe
......@@ -17,20 +17,21 @@
#include <asm/delay.h>
#include <asm/hypervisor.h>
unsigned int cpu_khz; /* TSC clocks / usec, not used here */
unsigned int __read_mostly cpu_khz; /* TSC clocks / usec, not used here */
EXPORT_SYMBOL(cpu_khz);
unsigned int tsc_khz;
unsigned int __read_mostly tsc_khz;
EXPORT_SYMBOL(tsc_khz);
/*
* TSC can be unstable due to cpufreq or due to unsynced TSCs
*/
static int tsc_unstable;
static int __read_mostly tsc_unstable;
/* native_sched_clock() is called before tsc_init(), so
we must start with the TSC soft disabled to prevent
erroneous rdtsc usage on !cpu_has_tsc processors */
static int tsc_disabled = -1;
static int __read_mostly tsc_disabled = -1;
static int tsc_clocksource_reliable;
/*
......
include/linux/init_task.h
View file @ 831576fe
......@@ -147,6 +147,7 @@ extern struct cred init_cred;
.nr_cpus_allowed = NR_CPUS, \
}, \
.tasks = LIST_HEAD_INIT(tsk.tasks), \
.pushable_tasks = PLIST_NODE_INIT(tsk.pushable_tasks, MAX_PRIO), \
.ptraced = LIST_HEAD_INIT(tsk.ptraced), \
.ptrace_entry = LIST_HEAD_INIT(tsk.ptrace_entry), \
.real_parent = &tsk, \
......
include/linux/latencytop.h
View file @ 831576fe
......@@ -9,6 +9,7 @@
#ifndef _INCLUDE_GUARD_LATENCYTOP_H_
#define _INCLUDE_GUARD_LATENCYTOP_H_
#include <linux/compiler.h>
#ifdef CONFIG_LATENCYTOP
#define LT_SAVECOUNT 32
......@@ -24,7 +25,14 @@ struct latency_record {
struct task_struct;
void account_scheduler_latency(struct task_struct *task, int usecs, int inter);
extern int latencytop_enabled;
void __account_scheduler_latency(struct task_struct *task, int usecs, int inter);
static inline void
account_scheduler_latency(struct task_struct *task, int usecs, int inter)
{
if (unlikely(latencytop_enabled))
__account_scheduler_latency(task, usecs, inter);
}
void clear_all_latency_tracing(struct task_struct *p);
......
include/linux/plist.h
View file @ 831576fe
......@@ -96,6 +96,10 @@ struct plist_node {
# define PLIST_HEAD_LOCK_INIT(_lock)
#endif
#define _PLIST_HEAD_INIT(head) \
.prio_list = LIST_HEAD_INIT((head).prio_list), \
.node_list = LIST_HEAD_INIT((head).node_list)
/**
* PLIST_HEAD_INIT - static struct plist_head initializer
* @head: struct plist_head variable name
......@@ -103,8 +107,7 @@ struct plist_node {
*/
#define PLIST_HEAD_INIT(head, _lock) \
{ \
.prio_list = LIST_HEAD_INIT((head).prio_list), \
.node_list = LIST_HEAD_INIT((head).node_list), \
_PLIST_HEAD_INIT(head), \
PLIST_HEAD_LOCK_INIT(&(_lock)) \
}
......@@ -116,7 +119,7 @@ struct plist_node {
#define PLIST_NODE_INIT(node, __prio) \
{ \
.prio = (__prio), \
.plist = PLIST_HEAD_INIT((node).plist, NULL), \
.plist = { _PLIST_HEAD_INIT((node).plist) }, \
}
/**
......
include/linux/sched.h
View file @ 831576fe
......@@ -998,6 +998,7 @@ struct sched_class {
struct rq *busiest, struct sched_domain *sd,
enum cpu_idle_type idle);
void (*pre_schedule) (struct rq *this_rq, struct task_struct *task);
int (*needs_post_schedule) (struct rq *this_rq);
void (*post_schedule) (struct rq *this_rq);
void (*task_wake_up) (struct rq *this_rq, struct task_struct *task);
......@@ -1052,6 +1053,10 @@ struct sched_entity {
u64 last_wakeup;
u64 avg_overlap;
u64 start_runtime;
u64 avg_wakeup;
u64 nr_migrations;
#ifdef CONFIG_SCHEDSTATS
u64 wait_start;
u64 wait_max;
......@@ -1067,7 +1072,6 @@ struct sched_entity {
u64 exec_max;
u64 slice_max;
u64 nr_migrations;
u64 nr_migrations_cold;
u64 nr_failed_migrations_affine;
u64 nr_failed_migrations_running;
......@@ -1164,6 +1168,7 @@ struct task_struct {
#endif
struct list_head tasks;
struct plist_node pushable_tasks;
struct mm_struct *mm, *active_mm;
......@@ -1675,6 +1680,16 @@ static inline int set_cpus_allowed(struct task_struct *p, cpumask_t new_mask)
return set_cpus_allowed_ptr(p, &new_mask);
}
/*
* Architectures can set this to 1 if they have specified
* CONFIG_HAVE_UNSTABLE_SCHED_CLOCK in their arch Kconfig,
* but then during bootup it turns out that sched_clock()
* is reliable after all:
*/
#ifdef CONFIG_HAVE_UNSTABLE_SCHED_CLOCK
extern int sched_clock_stable;
#endif
extern unsigned long long sched_clock(void);
extern void sched_clock_init(void);
......
init/Kconfig
View file @ 831576fe
......@@ -966,7 +966,6 @@ config SLABINFO
config RT_MUTEXES
boolean
select PLIST
config BASE_SMALL
int
......
kernel/latencytop.c
View file @ 831576fe
......@@ -9,6 +9,44 @@
* as published by the Free Software Foundation; version 2
* of the License.
*/
/*
* CONFIG_LATENCYTOP enables a kernel latency tracking infrastructure that is
* used by the "latencytop" userspace tool. The latency that is tracked is not
* the 'traditional' interrupt latency (which is primarily caused by something
* else consuming CPU), but instead, it is the latency an application encounters
* because the kernel sleeps on its behalf for various reasons.
*
* This code tracks 2 levels of statistics:
* 1) System level latency
* 2) Per process latency
*
* The latency is stored in fixed sized data structures in an accumulated form;
* if the "same" latency cause is hit twice, this will be tracked as one entry
* in the data structure. Both the count, total accumulated latency and maximum
* latency are tracked in this data structure. When the fixed size structure is
* full, no new causes are tracked until the buffer is flushed by writing to
* the /proc file; the userspace tool does this on a regular basis.
*
* A latency cause is identified by a stringified backtrace at the point that
* the scheduler gets invoked. The userland tool will use this string to
* identify the cause of the latency in human readable form.
*
* The information is exported via /proc/latency_stats and /proc/<pid>/latency.
* These files look like this:
*
* Latency Top version : v0.1
* 70 59433 4897 i915_irq_wait drm_ioctl vfs_ioctl do_vfs_ioctl sys_ioctl
* | | | |
* | | | +----> the stringified backtrace
* | | +---------> The maximum latency for this entry in microseconds
* | +--------------> The accumulated latency for this entry (microseconds)
* +-------------------> The number of times this entry is hit
*
* (note: the average latency is the accumulated latency divided by the number
* of times)
*/
#include <linux/latencytop.h>
#include <linux/kallsyms.h>
#include <linux/seq_file.h>
......@@ -72,7 +110,7 @@ account_global_scheduler_latency(struct task_struct *tsk, struct latency_record
firstnonnull = i;
continue;
}
for (q = 0 ; q < LT_BACKTRACEDEPTH ; q++) {
for (q = 0; q < LT_BACKTRACEDEPTH; q++) {
unsigned long record = lat->backtrace[q];
if (latency_record[i].backtrace[q] != record) {
......@@ -101,31 +139,52 @@ account_global_scheduler_latency(struct task_struct *tsk, struct latency_record
memcpy(&latency_record[i], lat, sizeof(struct latency_record));
}
static inline void store_stacktrace(struct task_struct *tsk, struct latency_record *lat)
/*
* Iterator to store a backtrace into a latency record entry
*/
static inline void store_stacktrace(struct task_struct *tsk,
struct latency_record *lat)
{
struct stack_trace trace;
memset(&trace, 0, sizeof(trace));
trace.max_entries = LT_BACKTRACEDEPTH;
trace.entries = &lat->backtrace[0];
trace.skip = 0;
save_stack_trace_tsk(tsk, &trace);
}
/**
* __account_scheduler_latency - record an occured latency
* @tsk - the task struct of the task hitting the latency
* @usecs - the duration of the latency in microseconds
* @inter - 1 if the sleep was interruptible, 0 if uninterruptible
*
* This function is the main entry point for recording latency entries
* as called by the scheduler.
*
* This function has a few special cases to deal with normal 'non-latency'
* sleeps: specifically, interruptible sleep longer than 5 msec is skipped
* since this usually is caused by waiting for events via select() and co.
*
* Negative latencies (caused by time going backwards) are also explicitly
* skipped.
*/
void __sched
account_scheduler_latency(struct task_struct *tsk, int usecs, int inter)
__account_scheduler_latency(struct task_struct *tsk, int usecs, int inter)
{
unsigned long flags;
int i, q;
struct latency_record lat;
if (!latencytop_enabled)
return;
/* Long interruptible waits are generally user requested... */
if (inter && usecs > 5000)
return;
/* Negative sleeps are time going backwards */
/* Zero-time sleeps are non-interesting */
if (usecs <= 0)
return;
memset(&lat, 0, sizeof(lat));
lat.count = 1;
lat.time = usecs;
......@@ -143,12 +202,12 @@ account_scheduler_latency(struct task_struct *tsk, int usecs, int inter)
if (tsk->latency_record_count >= LT_SAVECOUNT)
goto out_unlock;
for (i = 0; i < LT_SAVECOUNT ; i++) {
for (i = 0; i < LT_SAVECOUNT; i++) {
struct latency_record *mylat;
int same = 1;
mylat = &tsk->latency_record[i];
for (q = 0 ; q < LT_BACKTRACEDEPTH ; q++) {
for (q = 0; q < LT_BACKTRACEDEPTH; q++) {
unsigned long record = lat.backtrace[q];
if (mylat->backtrace[q] != record) {
......@@ -186,7 +245,7 @@ static int lstats_show(struct seq_file *m, void *v)
for (i = 0; i < MAXLR; i++) {
if (latency_record[i].backtrace[0]) {
int q;
seq_printf(m, "%i %li %li ",
seq_printf(m, "%i %lu %lu ",
latency_record[i].count,
latency_record[i].time,
latency_record[i].max);
......@@ -223,7 +282,7 @@ static int lstats_open(struct inode *inode, struct file *filp)
return single_open(filp, lstats_show, NULL);
}
static struct file_operations lstats_fops = {
static const struct file_operations lstats_fops = {
.open = lstats_open,
.read = seq_read,
.write = lstats_write,
......@@ -236,4 +295,4 @@ static int __init init_lstats_procfs(void)
proc_create("latency_stats", 0644, NULL, &lstats_fops);
return 0;
}
__initcall(init_lstats_procfs);
device_initcall(init_lstats_procfs);
kernel/sched.c
View file @ 831576fe
......@@ -331,6 +331,13 @@ static DEFINE_PER_CPU(struct rt_rq, init_rt_rq) ____cacheline_aligned_in_smp;
*/
static DEFINE_SPINLOCK(task_group_lock);
#ifdef CONFIG_SMP
static int root_task_group_empty(void)
{
return list_empty(&root_task_group.children);
}
#endif
#ifdef CONFIG_FAIR_GROUP_SCHED
#ifdef CONFIG_USER_SCHED
# define INIT_TASK_GROUP_LOAD (2*NICE_0_LOAD)
......@@ -391,6 +398,13 @@ static inline void set_task_rq(struct task_struct *p, unsigned int cpu)
#else
#ifdef CONFIG_SMP
static int root_task_group_empty(void)
{
return 1;
}
#endif
static inline void set_task_rq(struct task_struct *p, unsigned int cpu) { }
static inline struct task_group *task_group(struct task_struct *p)
{
......@@ -467,11 +481,17 @@ struct rt_rq {
struct rt_prio_array active;
unsigned long rt_nr_running;
#if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
int highest_prio; /* highest queued rt task prio */
struct {
int curr; /* highest queued rt task prio */
#ifdef CONFIG_SMP
int next; /* next highest */
#endif
} highest_prio;
#endif
#ifdef CONFIG_SMP
unsigned long rt_nr_migratory;
int overloaded;
struct plist_head pushable_tasks;
#endif
int rt_throttled;
u64 rt_time;
......@@ -549,7 +569,6 @@ struct rq {
unsigned long nr_running;
#define CPU_LOAD_IDX_MAX 5
unsigned long cpu_load[CPU_LOAD_IDX_MAX];
unsigned char idle_at_tick;
#ifdef CONFIG_NO_HZ
unsigned long last_tick_seen;
unsigned char in_nohz_recently;
......@@ -590,6 +609,7 @@ struct rq {
struct root_domain *rd;
struct sched_domain *sd;
unsigned char idle_at_tick;
/* For active balancing */
int active_balance;
int push_cpu;
......@@ -618,9 +638,6 @@ struct rq {
/* could above be rq->cfs_rq.exec_clock + rq->rt_rq.rt_runtime ? */
/* sys_sched_yield() stats */
unsigned int yld_exp_empty;
unsigned int yld_act_empty;
unsigned int yld_both_empty;
unsigned int yld_count;
/* schedule() stats */
......@@ -1183,10 +1200,10 @@ static void resched_task(struct task_struct *p)
assert_spin_locked(&task_rq(p)->lock);
if (unlikely(test_tsk_thread_flag(p, TIF_NEED_RESCHED)))
if (test_tsk_need_resched(p))
return;
set_tsk_thread_flag(p, TIF_NEED_RESCHED);
set_tsk_need_resched(p);
cpu = task_cpu(p);
if (cpu == smp_processor_id())
......@@ -1242,7 +1259,7 @@ void wake_up_idle_cpu(int cpu)
* lockless. The worst case is that the other CPU runs the
* idle task through an additional NOOP schedule()
*/
set_tsk_thread_flag(rq->idle, TIF_NEED_RESCHED);
set_tsk_need_resched(rq->idle);
/* NEED_RESCHED must be visible before we test polling */
smp_mb();
......@@ -1610,21 +1627,42 @@ static inline void update_shares_locked(struct rq *rq, struct sched_domain *sd)
#endif
#ifdef CONFIG_PREEMPT
/*
* double_lock_balance - lock the busiest runqueue, this_rq is locked already.
* fair double_lock_balance: Safely acquires both rq->locks in a fair
* way at the expense of forcing extra atomic operations in all
* invocations. This assures that the double_lock is acquired using the
* same underlying policy as the spinlock_t on this architecture, which
* reduces latency compared to the unfair variant below. However, it
* also adds more overhead and therefore may reduce throughput.
*/
static int double_lock_balance(struct rq *this_rq, struct rq *busiest)
static inline int _double_lock_balance(struct rq *this_rq, struct rq *busiest)
__releases(this_rq->lock)
__acquires(busiest->lock)
__acquires(this_rq->lock)
{
spin_unlock(&this_rq->lock);
double_rq_lock(this_rq, busiest);
return 1;
}
#else
/*
* Unfair double_lock_balance: Optimizes throughput at the expense of
* latency by eliminating extra atomic operations when the locks are
* already in proper order on entry. This favors lower cpu-ids and will
* grant the double lock to lower cpus over higher ids under contention,
* regardless of entry order into the function.
*/
static int _double_lock_balance(struct rq *this_rq, struct rq *busiest)
__releases(this_rq->lock)
__acquires(busiest->lock)
__acquires(this_rq->lock)
{
int ret = 0;
if (unlikely(!irqs_disabled())) {
/* printk() doesn't work good under rq->lock */
spin_unlock(&this_rq->lock);
BUG_ON(1);
}
if (unlikely(!spin_trylock(&busiest->lock))) {
if (busiest < this_rq) {
spin_unlock(&this_rq->lock);
......@@ -1637,6 +1675,22 @@ static int double_lock_balance(struct rq *this_rq, struct rq *busiest)
return ret;
}
#endif /* CONFIG_PREEMPT */
/*
* double_lock_balance - lock the busiest runqueue, this_rq is locked already.
*/
static int double_lock_balance(struct rq *this_rq, struct rq *busiest)
{
if (unlikely(!irqs_disabled())) {
/* printk() doesn't work good under rq->lock */
spin_unlock(&this_rq->lock);
BUG_ON(1);
}
return _double_lock_balance(this_rq, busiest);
}
static inline void double_unlock_balance(struct rq *this_rq, struct rq *busiest)
__releases(busiest->lock)
{
......@@ -1705,6 +1759,9 @@ static void update_avg(u64 *avg, u64 sample)
static void enqueue_task(struct rq *rq, struct task_struct *p, int wakeup)
{
if (wakeup)
p->se.start_runtime = p->se.sum_exec_runtime;
sched_info_queued(p);
p->sched_class->enqueue_task(rq, p, wakeup);
p->se.on_rq = 1;
......@@ -1712,10 +1769,15 @@ static void enqueue_task(struct rq *rq, struct task_struct *p, int wakeup)
static void dequeue_task(struct rq *rq, struct task_struct *p, int sleep)
{
if (sleep && p->se.last_wakeup) {
update_avg(&p->se.avg_overlap,
p->se.sum_exec_runtime - p->se.last_wakeup);
p->se.last_wakeup = 0;
if (sleep) {
if (p->se.last_wakeup) {
update_avg(&p->se.avg_overlap,
p->se.sum_exec_runtime - p->se.last_wakeup);
p->se.last_wakeup = 0;
} else {
update_avg(&p->se.avg_wakeup,
sysctl_sched_wakeup_granularity);
}
}
sched_info_dequeued(p);
......@@ -2017,7 +2079,7 @@ unsigned long wait_task_inactive(struct task_struct *p, long match_state)
* it must be off the runqueue _entirely_, and not
* preempted!
*
* So if it wa still runnable (but just not actively
* So if it was still runnable (but just not actively
* running right now), it's preempted, and we should
* yield - it could be a while.
*/
......@@ -2267,7 +2329,7 @@ static int try_to_wake_up(struct task_struct *p, unsigned int state, int sync)
sync = 0;
#ifdef CONFIG_SMP
if (sched_feat(LB_WAKEUP_UPDATE)) {
if (sched_feat(LB_WAKEUP_UPDATE) && !root_task_group_empty()) {
struct sched_domain *sd;
this_cpu = raw_smp_processor_id();
......@@ -2345,6 +2407,22 @@ static int try_to_wake_up(struct task_struct *p, unsigned int state, int sync)
activate_task(rq, p, 1);
success = 1;
/*
* Only attribute actual wakeups done by this task.
*/
if (!in_interrupt()) {
struct sched_entity *se = &current->se;
u64 sample = se->sum_exec_runtime;
if (se->last_wakeup)
sample -= se->last_wakeup;
else
sample -= se->start_runtime;
update_avg(&se->avg_wakeup, sample);
se->last_wakeup = se->sum_exec_runtime;
}
out_running:
trace_sched_wakeup(rq, p, success);
check_preempt_curr(rq, p, sync);
......@@ -2355,8 +2433,6 @@ static int try_to_wake_up(struct task_struct *p, unsigned int state, int sync)
p->sched_class->task_wake_up(rq, p);
#endif
out:
current->se.last_wakeup = current->se.sum_exec_runtime;
task_rq_unlock(rq, &flags);
return success;
......@@ -2386,6 +2462,8 @@ static void __sched_fork(struct task_struct *p)
p->se.prev_sum_exec_runtime = 0;
p->se.last_wakeup = 0;
p->se.avg_overlap = 0;
p->se.start_runtime = 0;
p->se.avg_wakeup = sysctl_sched_wakeup_granularity;
#ifdef CONFIG_SCHEDSTATS
p->se.wait_start = 0;
......@@ -2448,6 +2526,8 @@ void sched_fork(struct task_struct *p, int clone_flags)
/* Want to start with kernel preemption disabled. */
task_thread_info(p)->preempt_count = 1;
#endif
plist_node_init(&p->pushable_tasks, MAX_PRIO);
put_cpu();
}
......@@ -2491,7 +2571,7 @@ void wake_up_new_task(struct task_struct *p, unsigned long clone_flags)
#ifdef CONFIG_PREEMPT_NOTIFIERS
/**
* preempt_notifier_register - tell me when current is being being preempted & rescheduled
* preempt_notifier_register - tell me when current is being preempted & rescheduled
* @notifier: notifier struct to register
*/
void preempt_notifier_register(struct preempt_notifier *notifier)
......@@ -2588,6 +2668,12 @@ static void finish_task_switch(struct rq *rq, struct task_struct *prev)
{
struct mm_struct *mm = rq->prev_mm;
long prev_state;
#ifdef CONFIG_SMP
int post_schedule = 0;
if (current->sched_class->needs_post_schedule)
post_schedule = current->sched_class->needs_post_schedule(rq);
#endif
rq->prev_mm = NULL;
......@@ -2606,7 +2692,7 @@ static void finish_task_switch(struct rq *rq, struct task_struct *prev)
finish_arch_switch(prev);
finish_lock_switch(rq, prev);
#ifdef CONFIG_SMP
if (current->sched_class->post_schedule)
if (post_schedule)
current->sched_class->post_schedule(rq);
#endif
......@@ -2913,6 +2999,7 @@ int can_migrate_task(struct task_struct *p, struct rq *rq, int this_cpu,
struct sched_domain *sd, enum cpu_idle_type idle,
int *all_pinned)
{
int tsk_cache_hot = 0;
/*
* We do not migrate tasks that are:
* 1) running (obviously), or
......@@ -2936,10 +3023,11 @@ int can_migrate_task(struct task_struct *p, struct rq *rq, int this_cpu,
* 2) too many balance attempts have failed.
*/
if (!task_hot(p, rq->clock, sd) ||
sd->nr_balance_failed > sd->cache_nice_tries) {
tsk_cache_hot = task_hot(p, rq->clock, sd);
if (!tsk_cache_hot ||
sd->nr_balance_failed > sd->cache_nice_tries) {
#ifdef CONFIG_SCHEDSTATS
if (task_hot(p, rq->clock, sd)) {
if (tsk_cache_hot) {
schedstat_inc(sd, lb_hot_gained[idle]);
schedstat_inc(p, se.nr_forced_migrations);
}
......@@ -2947,7 +3035,7 @@ int can_migrate_task(struct task_struct *p, struct rq *rq, int this_cpu,
return 1;
}
if (task_hot(p, rq->clock, sd)) {
if (tsk_cache_hot) {
schedstat_inc(p, se.nr_failed_migrations_hot);
return 0;
}
......@@ -2987,6 +3075,16 @@ balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest,
pulled++;
rem_load_move -= p->se.load.weight;
#ifdef CONFIG_PREEMPT
/*
* NEWIDLE balancing is a source of latency, so preemptible kernels
* will stop after the first task is pulled to minimize the critical
* section.
*/
if (idle == CPU_NEWLY_IDLE)
goto out;
#endif
/*
* We only want to steal up to the prescribed amount of weighted load.
*/
......@@ -3033,9 +3131,15 @@ static int move_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest,
sd, idle, all_pinned, &this_best_prio);
class = class->next;
#ifdef CONFIG_PREEMPT
/*
* NEWIDLE balancing is a source of latency, so preemptible
* kernels will stop after the first task is pulled to minimize
* the critical section.
*/
if (idle == CPU_NEWLY_IDLE && this_rq->nr_running)
break;
#endif
} while (class && max_load_move > total_load_moved);
return total_load_moved > 0;
......@@ -3085,246 +3189,479 @@ static int move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest,
return 0;
}
/********** Helpers for find_busiest_group ************************/
/**
* sd_lb_stats - Structure to store the statistics of a sched_domain
* during load balancing.
*/
struct sd_lb_stats {
struct sched_group *busiest; /* Busiest group in this sd */
struct sched_group *this; /* Local group in this sd */
unsigned long total_load; /* Total load of all groups in sd */
unsigned long total_pwr; /* Total power of all groups in sd */
unsigned long avg_load; /* Average load across all groups in sd */
/** Statistics of this group */
unsigned long this_load;
unsigned long this_load_per_task;
unsigned long this_nr_running;
/* Statistics of the busiest group */
unsigned long max_load;
unsigned long busiest_load_per_task;
unsigned long busiest_nr_running;
int group_imb; /* Is there imbalance in this sd */
#if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
int power_savings_balance; /* Is powersave balance needed for this sd */
struct sched_group *group_min; /* Least loaded group in sd */
struct sched_group *group_leader; /* Group which relieves group_min */
unsigned long min_load_per_task; /* load_per_task in group_min */
unsigned long leader_nr_running; /* Nr running of group_leader */
unsigned long min_nr_running; /* Nr running of group_min */
#endif
};
/*
* find_busiest_group finds and returns the busiest CPU group within the
* domain. It calculates and returns the amount of weighted load which
* should be moved to restore balance via the imbalance parameter.
/**
* sg_lb_stats - stats of a sched_group required for load_balancing
*/
struct sg_lb_stats {
unsigned long avg_load; /*Avg load across the CPUs of the group */
unsigned long group_load; /* Total load over the CPUs of the group */
unsigned long sum_nr_running; /* Nr tasks running in the group */
unsigned long sum_weighted_load; /* Weighted load of group's tasks */
unsigned long group_capacity;
int group_imb; /* Is there an imbalance in the group ? */
};
/**
* group_first_cpu - Returns the first cpu in the cpumask of a sched_group.
* @group: The group whose first cpu is to be returned.
*/
static struct sched_group *
find_busiest_group(struct sched_domain *sd, int this_cpu,
unsigned long *imbalance, enum cpu_idle_type idle,
int *sd_idle, const struct cpumask *cpus, int *balance)
static inline unsigned int group_first_cpu(struct sched_group *group)
{
struct sched_group *busiest = NULL, *this = NULL, *group = sd->groups;
unsigned long max_load, avg_load, total_load, this_load, total_pwr;
unsigned long max_pull;
unsigned long busiest_load_per_task, busiest_nr_running;
unsigned long this_load_per_task, this_nr_running;
int load_idx, group_imb = 0;
#if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
int power_savings_balance = 1;
unsigned long leader_nr_running = 0, min_load_per_task = 0;
unsigned long min_nr_running = ULONG_MAX;
struct sched_group *group_min = NULL, *group_leader = NULL;
#endif
return cpumask_first(sched_group_cpus(group));
}
max_load = this_load = total_load = total_pwr = 0;
busiest_load_per_task = busiest_nr_running = 0;
this_load_per_task = this_nr_running = 0;
/**
* get_sd_load_idx - Obtain the load index for a given sched domain.
* @sd: The sched_domain whose load_idx is to be obtained.
* @idle: The Idle status of the CPU for whose sd load_icx is obtained.
*/
static inline int get_sd_load_idx(struct sched_domain *sd,
enum cpu_idle_type idle)
{
int load_idx;
if (idle == CPU_NOT_IDLE)
switch (idle) {
case CPU_NOT_IDLE:
load_idx = sd->busy_idx;
else if (idle == CPU_NEWLY_IDLE)
break;
case CPU_NEWLY_IDLE:
load_idx = sd->newidle_idx;
else
break;
default:
load_idx = sd->idle_idx;
break;
}
do {
unsigned long load, group_capacity, max_cpu_load, min_cpu_load;
int local_group;
int i;
int __group_imb = 0;
unsigned int balance_cpu = -1, first_idle_cpu = 0;
unsigned long sum_nr_running, sum_weighted_load;
unsigned long sum_avg_load_per_task;
unsigned long avg_load_per_task;
return load_idx;
}
local_group = cpumask_test_cpu(this_cpu,
sched_group_cpus(group));
if (local_group)
balance_cpu = cpumask_first(sched_group_cpus(group));
#if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
/**
* init_sd_power_savings_stats - Initialize power savings statistics for
* the given sched_domain, during load balancing.
*
* @sd: Sched domain whose power-savings statistics are to be initialized.
* @sds: Variable containing the statistics for sd.
* @idle: Idle status of the CPU at which we're performing load-balancing.
*/
static inline void init_sd_power_savings_stats(struct sched_domain *sd,
struct sd_lb_stats *sds, enum cpu_idle_type idle)
{
/*
* Busy processors will not participate in power savings
* balance.
*/
if (idle == CPU_NOT_IDLE || !(sd->flags & SD_POWERSAVINGS_BALANCE))
sds->power_savings_balance = 0;
else {
sds->power_savings_balance = 1;
sds->min_nr_running = ULONG_MAX;
sds->leader_nr_running = 0;
}
}
/* Tally up the load of all CPUs in the group */
sum_weighted_load = sum_nr_running = avg_load = 0;
sum_avg_load_per_task = avg_load_per_task = 0;
/**
* update_sd_power_savings_stats - Update the power saving stats for a
* sched_domain while performing load balancing.
*
* @group: sched_group belonging to the sched_domain under consideration.
* @sds: Variable containing the statistics of the sched_domain
* @local_group: Does group contain the CPU for which we're performing
* load balancing ?
* @sgs: Variable containing the statistics of the group.
*/
static inline void update_sd_power_savings_stats(struct sched_group *group,
struct sd_lb_stats *sds, int local_group, struct sg_lb_stats *sgs)
{
max_cpu_load = 0;
min_cpu_load = ~0UL;
if (!sds->power_savings_balance)
return;
for_each_cpu_and(i, sched_group_cpus(group), cpus) {
struct rq *rq = cpu_rq(i);
/*
* If the local group is idle or completely loaded
* no need to do power savings balance at this domain
*/
if (local_group && (sds->this_nr_running >= sgs->group_capacity ||
!sds->this_nr_running))
sds->power_savings_balance = 0;
if (*sd_idle && rq->nr_running)
*sd_idle = 0;
/*
* If a group is already running at full capacity or idle,
* don't include that group in power savings calculations
*/
if (!sds->power_savings_balance ||
sgs->sum_nr_running >= sgs->group_capacity ||
!sgs->sum_nr_running)
return;
/* Bias balancing toward cpus of our domain */
if (local_group) {
if (idle_cpu(i) && !first_idle_cpu) {
first_idle_cpu = 1;
balance_cpu = i;
}
/*
* Calculate the group which has the least non-idle load.
* This is the group from where we need to pick up the load
* for saving power
*/
if ((sgs->sum_nr_running < sds->min_nr_running) ||
(sgs->sum_nr_running == sds->min_nr_running &&
group_first_cpu(group) > group_first_cpu(sds->group_min))) {
sds->group_min = group;
sds->min_nr_running = sgs->sum_nr_running;
sds->min_load_per_task = sgs->sum_weighted_load /
sgs->sum_nr_running;
}
load = target_load(i, load_idx);
} else {
load = source_load(i, load_idx);
if (load > max_cpu_load)
max_cpu_load = load;
if (min_cpu_load > load)
min_cpu_load = load;
}
/*
* Calculate the group which is almost near its
* capacity but still has some space to pick up some load
* from other group and save more power
*/
if (sgs->sum_nr_running > sgs->group_capacity - 1)
return;
avg_load += load;
sum_nr_running += rq->nr_running;
sum_weighted_load += weighted_cpuload(i);
if (sgs->sum_nr_running > sds->leader_nr_running ||
(sgs->sum_nr_running == sds->leader_nr_running &&
group_first_cpu(group) < group_first_cpu(sds->group_leader))) {
sds->group_leader = group;
sds->leader_nr_running = sgs->sum_nr_running;
}
}
sum_avg_load_per_task += cpu_avg_load_per_task(i);
}
/**
* check_power_save_busiest_group - Check if we have potential to perform
* some power-savings balance. If yes, set the busiest group to be
* the least loaded group in the sched_domain, so that it's CPUs can
* be put to idle.
*
* @sds: Variable containing the statistics of the sched_domain
* under consideration.
* @this_cpu: Cpu at which we're currently performing load-balancing.
* @imbalance: Variable to store the imbalance.
*
* Returns 1 if there is potential to perform power-savings balance.
* Else returns 0.
*/
static inline int check_power_save_busiest_group(struct sd_lb_stats *sds,
int this_cpu, unsigned long *imbalance)
{
if (!sds->power_savings_balance)
return 0;
/*
* First idle cpu or the first cpu(busiest) in this sched group
* is eligible for doing load balancing at this and above
* domains. In the newly idle case, we will allow all the cpu's
* to do the newly idle load balance.
*/
if (idle != CPU_NEWLY_IDLE && local_group &&
balance_cpu != this_cpu && balance) {
*balance = 0;
goto ret;
}
if (sds->this != sds->group_leader ||
sds->group_leader == sds->group_min)
return 0;
total_load += avg_load;
total_pwr += group->__cpu_power;
*imbalance = sds->min_load_per_task;
sds->busiest = sds->group_min;
/* Adjust by relative CPU power of the group */
avg_load = sg_div_cpu_power(group,
avg_load * SCHED_LOAD_SCALE);
if (sched_mc_power_savings >= POWERSAVINGS_BALANCE_WAKEUP) {
cpu_rq(this_cpu)->rd->sched_mc_preferred_wakeup_cpu =
group_first_cpu(sds->group_leader);
}
return 1;
/*
* Consider the group unbalanced when the imbalance is larger
* than the average weight of two tasks.
*
* APZ: with cgroup the avg task weight can vary wildly and
* might not be a suitable number - should we keep a
* normalized nr_running number somewhere that negates
* the hierarchy?
*/
avg_load_per_task = sg_div_cpu_power(group,
sum_avg_load_per_task * SCHED_LOAD_SCALE);
}
#else /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */
static inline void init_sd_power_savings_stats(struct sched_domain *sd,
struct sd_lb_stats *sds, enum cpu_idle_type idle)
{
return;
}
if ((max_cpu_load - min_cpu_load) > 2*avg_load_per_task)
__group_imb = 1;
static inline void update_sd_power_savings_stats(struct sched_group *group,
struct sd_lb_stats *sds, int local_group, struct sg_lb_stats *sgs)
{
return;
}
static inline int check_power_save_busiest_group(struct sd_lb_stats *sds,
int this_cpu, unsigned long *imbalance)
{
return 0;
}
#endif /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */
group_capacity = group->__cpu_power / SCHED_LOAD_SCALE;
/**
* update_sg_lb_stats - Update sched_group's statistics for load balancing.
* @group: sched_group whose statistics are to be updated.
* @this_cpu: Cpu for which load balance is currently performed.
* @idle: Idle status of this_cpu
* @load_idx: Load index of sched_domain of this_cpu for load calc.
* @sd_idle: Idle status of the sched_domain containing group.
* @local_group: Does group contain this_cpu.
* @cpus: Set of cpus considered for load balancing.
* @balance: Should we balance.
* @sgs: variable to hold the statistics for this group.
*/
static inline void update_sg_lb_stats(struct sched_group *group, int this_cpu,
enum cpu_idle_type idle, int load_idx, int *sd_idle,
int local_group, const struct cpumask *cpus,
int *balance, struct sg_lb_stats *sgs)
{
unsigned long load, max_cpu_load, min_cpu_load;
int i;
unsigned int balance_cpu = -1, first_idle_cpu = 0;
unsigned long sum_avg_load_per_task;
unsigned long avg_load_per_task;
if (local_group)
balance_cpu = group_first_cpu(group);
/* Tally up the load of all CPUs in the group */
sum_avg_load_per_task = avg_load_per_task = 0;
max_cpu_load = 0;
min_cpu_load = ~0UL;
for_each_cpu_and(i, sched_group_cpus(group), cpus) {
struct rq *rq = cpu_rq(i);
if (*sd_idle && rq->nr_running)
*sd_idle = 0;
/* Bias balancing toward cpus of our domain */
if (local_group) {
this_load = avg_load;
this = group;
this_nr_running = sum_nr_running;
this_load_per_task = sum_weighted_load;
} else if (avg_load > max_load &&
(sum_nr_running > group_capacity || __group_imb)) {
max_load = avg_load;
busiest = group;
busiest_nr_running = sum_nr_running;
busiest_load_per_task = sum_weighted_load;
group_imb = __group_imb;
if (idle_cpu(i) && !first_idle_cpu) {
first_idle_cpu = 1;
balance_cpu = i;
}
load = target_load(i, load_idx);
} else {
load = source_load(i, load_idx);
if (load > max_cpu_load)
max_cpu_load = load;
if (min_cpu_load > load)
min_cpu_load = load;
}
#if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
/*
* Busy processors will not participate in power savings
* balance.
*/
if (idle == CPU_NOT_IDLE ||
!(sd->flags & SD_POWERSAVINGS_BALANCE))
goto group_next;
sgs->group_load += load;
sgs->sum_nr_running += rq->nr_running;
sgs->sum_weighted_load += weighted_cpuload(i);
/*
* If the local group is idle or completely loaded
* no need to do power savings balance at this domain
*/
if (local_group && (this_nr_running >= group_capacity ||
!this_nr_running))
power_savings_balance = 0;
sum_avg_load_per_task += cpu_avg_load_per_task(i);
}
/*
* If a group is already running at full capacity or idle,
* don't include that group in power savings calculations
*/
if (!power_savings_balance || sum_nr_running >= group_capacity
|| !sum_nr_running)
goto group_next;
/*
* First idle cpu or the first cpu(busiest) in this sched group
* is eligible for doing load balancing at this and above
* domains. In the newly idle case, we will allow all the cpu's
* to do the newly idle load balance.
*/
if (idle != CPU_NEWLY_IDLE && local_group &&
balance_cpu != this_cpu && balance) {
*balance = 0;
return;
}
/*
* Calculate the group which has the least non-idle load.
* This is the group from where we need to pick up the load
* for saving power
*/
if ((sum_nr_running < min_nr_running) ||
(sum_nr_running == min_nr_running &&
cpumask_first(sched_group_cpus(group)) >
cpumask_first(sched_group_cpus(group_min)))) {
group_min = group;
min_nr_running = sum_nr_running;
min_load_per_task = sum_weighted_load /
sum_nr_running;
}
/* Adjust by relative CPU power of the group */
sgs->avg_load = sg_div_cpu_power(group,
sgs->group_load * SCHED_LOAD_SCALE);
/*
* Calculate the group which is almost near its
* capacity but still has some space to pick up some load
* from other group and save more power
*/
if (sum_nr_running <= group_capacity - 1) {
if (sum_nr_running > leader_nr_running ||
(sum_nr_running == leader_nr_running &&
cpumask_first(sched_group_cpus(group)) <
cpumask_first(sched_group_cpus(group_leader)))) {
group_leader = group;
leader_nr_running = sum_nr_running;
}
/*
* Consider the group unbalanced when the imbalance is larger
* than the average weight of two tasks.
*
* APZ: with cgroup the avg task weight can vary wildly and
* might not be a suitable number - should we keep a
* normalized nr_running number somewhere that negates
* the hierarchy?
*/
avg_load_per_task = sg_div_cpu_power(group,
sum_avg_load_per_task * SCHED_LOAD_SCALE);
if ((max_cpu_load - min_cpu_load) > 2*avg_load_per_task)
sgs->group_imb = 1;
sgs->group_capacity = group->__cpu_power / SCHED_LOAD_SCALE;
}
/**
* update_sd_lb_stats - Update sched_group's statistics for load balancing.
* @sd: sched_domain whose statistics are to be updated.
* @this_cpu: Cpu for which load balance is currently performed.
* @idle: Idle status of this_cpu
* @sd_idle: Idle status of the sched_domain containing group.
* @cpus: Set of cpus considered for load balancing.
* @balance: Should we balance.
* @sds: variable to hold the statistics for this sched_domain.
*/
static inline void update_sd_lb_stats(struct sched_domain *sd, int this_cpu,
enum cpu_idle_type idle, int *sd_idle,
const struct cpumask *cpus, int *balance,
struct sd_lb_stats *sds)
{
struct sched_group *group = sd->groups;
struct sg_lb_stats sgs;
int load_idx;
init_sd_power_savings_stats(sd, sds, idle);
load_idx = get_sd_load_idx(sd, idle);
do {
int local_group;
local_group = cpumask_test_cpu(this_cpu,
sched_group_cpus(group));
memset(&sgs, 0, sizeof(sgs));
update_sg_lb_stats(group, this_cpu, idle, load_idx, sd_idle,
local_group, cpus, balance, &sgs);
if (local_group && balance && !(*balance))
return;
sds->total_load += sgs.group_load;
sds->total_pwr += group->__cpu_power;
if (local_group) {
sds->this_load = sgs.avg_load;
sds->this = group;
sds->this_nr_running = sgs.sum_nr_running;
sds->this_load_per_task = sgs.sum_weighted_load;
} else if (sgs.avg_load > sds->max_load &&
(sgs.sum_nr_running > sgs.group_capacity ||
sgs.group_imb)) {
sds->max_load = sgs.avg_load;
sds->busiest = group;
sds->busiest_nr_running = sgs.sum_nr_running;
sds->busiest_load_per_task = sgs.sum_weighted_load;
sds->group_imb = sgs.group_imb;
}
group_next:
#endif
update_sd_power_savings_stats(group, sds, local_group, &sgs);
group = group->next;
} while (group != sd->groups);
if (!busiest || this_load >= max_load || busiest_nr_running == 0)
goto out_balanced;
avg_load = (SCHED_LOAD_SCALE * total_load) / total_pwr;
}
if (this_load >= avg_load ||
100*max_load <= sd->imbalance_pct*this_load)
goto out_balanced;
/**
* fix_small_imbalance - Calculate the minor imbalance that exists
* amongst the groups of a sched_domain, during
* load balancing.
* @sds: Statistics of the sched_domain whose imbalance is to be calculated.
* @this_cpu: The cpu at whose sched_domain we're performing load-balance.
* @imbalance: Variable to store the imbalance.
*/
static inline void fix_small_imbalance(struct sd_lb_stats *sds,
int this_cpu, unsigned long *imbalance)
{
unsigned long tmp, pwr_now = 0, pwr_move = 0;
unsigned int imbn = 2;
if (sds->this_nr_running) {
sds->this_load_per_task /= sds->this_nr_running;
if (sds->busiest_load_per_task >
sds->this_load_per_task)
imbn = 1;
} else
sds->this_load_per_task =
cpu_avg_load_per_task(this_cpu);
busiest_load_per_task /= busiest_nr_running;
if (group_imb)
busiest_load_per_task = min(busiest_load_per_task, avg_load);
if (sds->max_load - sds->this_load + sds->busiest_load_per_task >=
sds->busiest_load_per_task * imbn) {
*imbalance = sds->busiest_load_per_task;
return;
}
/*
* We're trying to get all the cpus to the average_load, so we don't
* want to push ourselves above the average load, nor do we wish to
* reduce the max loaded cpu below the average load, as either of these
* actions would just result in more rebalancing later, and ping-pong
* tasks around. Thus we look for the minimum possible imbalance.
* Negative imbalances (*we* are more loaded than anyone else) will
* be counted as no imbalance for these purposes -- we can't fix that
* by pulling tasks to us. Be careful of negative numbers as they'll
* appear as very large values with unsigned longs.
* OK, we don't have enough imbalance to justify moving tasks,
* however we may be able to increase total CPU power used by
* moving them.
*/
if (max_load <= busiest_load_per_task)
goto out_balanced;
pwr_now += sds->busiest->__cpu_power *
min(sds->busiest_load_per_task, sds->max_load);
pwr_now += sds->this->__cpu_power *
min(sds->this_load_per_task, sds->this_load);
pwr_now /= SCHED_LOAD_SCALE;
/* Amount of load we'd subtract */
tmp = sg_div_cpu_power(sds->busiest,
sds->busiest_load_per_task * SCHED_LOAD_SCALE);
if (sds->max_load > tmp)
pwr_move += sds->busiest->__cpu_power *
min(sds->busiest_load_per_task, sds->max_load - tmp);
/* Amount of load we'd add */
if (sds->max_load * sds->busiest->__cpu_power <
sds->busiest_load_per_task * SCHED_LOAD_SCALE)
tmp = sg_div_cpu_power(sds->this,
sds->max_load * sds->busiest->__cpu_power);
else
tmp = sg_div_cpu_power(sds->this,
sds->busiest_load_per_task * SCHED_LOAD_SCALE);
pwr_move += sds->this->__cpu_power *
min(sds->this_load_per_task, sds->this_load + tmp);
pwr_move /= SCHED_LOAD_SCALE;
/* Move if we gain throughput */
if (pwr_move > pwr_now)
*imbalance = sds->busiest_load_per_task;
}
/**
* calculate_imbalance - Calculate the amount of imbalance present within the
* groups of a given sched_domain during load balance.
* @sds: statistics of the sched_domain whose imbalance is to be calculated.
* @this_cpu: Cpu for which currently load balance is being performed.
* @imbalance: The variable to store the imbalance.
*/
static inline void calculate_imbalance(struct sd_lb_stats *sds, int this_cpu,
unsigned long *imbalance)
{
unsigned long max_pull;
/*
* In the presence of smp nice balancing, certain scenarios can have
* max load less than avg load(as we skip the groups at or below
* its cpu_power, while calculating max_load..)
*/
if (max_load < avg_load) {
if (sds->max_load < sds->avg_load) {
*imbalance = 0;
goto small_imbalance;
return fix_small_imbalance(sds, this_cpu, imbalance);
}
/* Don't want to pull so many tasks that a group would go idle */
max_pull = min(max_load - avg_load, max_load - busiest_load_per_task);
max_pull = min(sds->max_load - sds->avg_load,
sds->max_load - sds->busiest_load_per_task);
/* How much load to actually move to equalise the imbalance */
*imbalance = min(max_pull * busiest->__cpu_power,
(avg_load - this_load) * this->__cpu_power)
*imbalance = min(max_pull * sds->busiest->__cpu_power,
(sds->avg_load - sds->this_load) * sds->this->__cpu_power)
/ SCHED_LOAD_SCALE;
/*
......@@ -3333,78 +3670,110 @@ find_busiest_group(struct sched_domain *sd, int this_cpu,
* a think about bumping its value to force at least one task to be
* moved
*/
if (*imbalance < busiest_load_per_task) {
unsigned long tmp, pwr_now, pwr_move;
unsigned int imbn;
small_imbalance:
pwr_move = pwr_now = 0;
imbn = 2;
if (this_nr_running) {
this_load_per_task /= this_nr_running;
if (busiest_load_per_task > this_load_per_task)
imbn = 1;
} else
this_load_per_task = cpu_avg_load_per_task(this_cpu);
if (*imbalance < sds->busiest_load_per_task)
return fix_small_imbalance(sds, this_cpu, imbalance);
if (max_load - this_load + busiest_load_per_task >=
busiest_load_per_task * imbn) {
*imbalance = busiest_load_per_task;
return busiest;
}
}
/******* find_busiest_group() helpers end here *********************/
/*
* OK, we don't have enough imbalance to justify moving tasks,
* however we may be able to increase total CPU power used by
* moving them.
*/
/**
* find_busiest_group - Returns the busiest group within the sched_domain
* if there is an imbalance. If there isn't an imbalance, and
* the user has opted for power-savings, it returns a group whose
* CPUs can be put to idle by rebalancing those tasks elsewhere, if
* such a group exists.
*
* Also calculates the amount of weighted load which should be moved
* to restore balance.
*
* @sd: The sched_domain whose busiest group is to be returned.
* @this_cpu: The cpu for which load balancing is currently being performed.
* @imbalance: Variable which stores amount of weighted load which should
* be moved to restore balance/put a group to idle.
* @idle: The idle status of this_cpu.
* @sd_idle: The idleness of sd
* @cpus: The set of CPUs under consideration for load-balancing.
* @balance: Pointer to a variable indicating if this_cpu
* is the appropriate cpu to perform load balancing at this_level.
*
* Returns: - the busiest group if imbalance exists.
* - If no imbalance and user has opted for power-savings balance,
* return the least loaded group whose CPUs can be
* put to idle by rebalancing its tasks onto our group.
*/
static struct sched_group *
find_busiest_group(struct sched_domain *sd, int this_cpu,
unsigned long *imbalance, enum cpu_idle_type idle,
int *sd_idle, const struct cpumask *cpus, int *balance)
{
struct sd_lb_stats sds;
pwr_now += busiest->__cpu_power *
min(busiest_load_per_task, max_load);
pwr_now += this->__cpu_power *
min(this_load_per_task, this_load);
pwr_now /= SCHED_LOAD_SCALE;
/* Amount of load we'd subtract */
tmp = sg_div_cpu_power(busiest,
busiest_load_per_task * SCHED_LOAD_SCALE);
if (max_load > tmp)
pwr_move += busiest->__cpu_power *
min(busiest_load_per_task, max_load - tmp);
/* Amount of load we'd add */
if (max_load * busiest->__cpu_power <
busiest_load_per_task * SCHED_LOAD_SCALE)
tmp = sg_div_cpu_power(this,
max_load * busiest->__cpu_power);
else
tmp = sg_div_cpu_power(this,
busiest_load_per_task * SCHED_LOAD_SCALE);
pwr_move += this->__cpu_power *
min(this_load_per_task, this_load + tmp);
pwr_move /= SCHED_LOAD_SCALE;
memset(&sds, 0, sizeof(sds));
/* Move if we gain throughput */
if (pwr_move > pwr_now)
*imbalance = busiest_load_per_task;
}
/*
* Compute the various statistics relavent for load balancing at
* this level.
*/
update_sd_lb_stats(sd, this_cpu, idle, sd_idle, cpus,
balance, &sds);
/* Cases where imbalance does not exist from POV of this_cpu */
/* 1) this_cpu is not the appropriate cpu to perform load balancing
* at this level.
* 2) There is no busy sibling group to pull from.
* 3) This group is the busiest group.
* 4) This group is more busy than the avg busieness at this
* sched_domain.
* 5) The imbalance is within the specified limit.
* 6) Any rebalance would lead to ping-pong
*/
if (balance && !(*balance))
goto ret;
return busiest;
if (!sds.busiest || sds.busiest_nr_running == 0)
goto out_balanced;
out_balanced:
#if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
if (idle == CPU_NOT_IDLE || !(sd->flags & SD_POWERSAVINGS_BALANCE))
goto ret;
if (sds.this_load >= sds.max_load)
goto out_balanced;
if (this == group_leader && group_leader != group_min) {
*imbalance = min_load_per_task;
if (sched_mc_power_savings >= POWERSAVINGS_BALANCE_WAKEUP) {
cpu_rq(this_cpu)->rd->sched_mc_preferred_wakeup_cpu =
cpumask_first(sched_group_cpus(group_leader));
}
return group_min;
}
#endif
sds.avg_load = (SCHED_LOAD_SCALE * sds.total_load) / sds.total_pwr;
if (sds.this_load >= sds.avg_load)
goto out_balanced;
if (100 * sds.max_load <= sd->imbalance_pct * sds.this_load)
goto out_balanced;
sds.busiest_load_per_task /= sds.busiest_nr_running;
if (sds.group_imb)
sds.busiest_load_per_task =
min(sds.busiest_load_per_task, sds.avg_load);
/*
* We're trying to get all the cpus to the average_load, so we don't
* want to push ourselves above the average load, nor do we wish to
* reduce the max loaded cpu below the average load, as either of these
* actions would just result in more rebalancing later, and ping-pong
* tasks around. Thus we look for the minimum possible imbalance.
* Negative imbalances (*we* are more loaded than anyone else) will
* be counted as no imbalance for these purposes -- we can't fix that
* by pulling tasks to us. Be careful of negative numbers as they'll
* appear as very large values with unsigned longs.
*/
if (sds.max_load <= sds.busiest_load_per_task)
goto out_balanced;
/* Looks like there is an imbalance. Compute it */
calculate_imbalance(&sds, this_cpu, imbalance);
return sds.busiest;
out_balanced:
/*
* There is no obvious imbalance. But check if we can do some balancing
* to save power.
*/
if (check_power_save_busiest_group(&sds, this_cpu, imbalance))
return sds.busiest;
ret:
*imbalance = 0;
return NULL;
......@@ -4057,6 +4426,11 @@ static void run_rebalance_domains(struct softirq_action *h)
#endif
}
static inline int on_null_domain(int cpu)
{
return !rcu_dereference(cpu_rq(cpu)->sd);
}
/*
* Trigger the SCHED_SOFTIRQ if it is time to do periodic load balancing.
*
......@@ -4114,7 +4488,9 @@ static inline void trigger_load_balance(struct rq *rq, int cpu)
cpumask_test_cpu(cpu, nohz.cpu_mask))
return;
#endif
if (time_after_eq(jiffies, rq->next_balance))
/* Don't need to rebalance while attached to NULL domain */
if (time_after_eq(jiffies, rq->next_balance) &&
likely(!on_null_domain(cpu)))
raise_softirq(SCHED_SOFTIRQ);
}
......@@ -4508,11 +4884,33 @@ static inline void schedule_debug(struct task_struct *prev)
#endif
}
static void put_prev_task(struct rq *rq, struct task_struct *prev)
{
if (prev->state == TASK_RUNNING) {
u64 runtime = prev->se.sum_exec_runtime;
runtime -= prev->se.prev_sum_exec_runtime;
runtime = min_t(u64, runtime, 2*sysctl_sched_migration_cost);
/*
* In order to avoid avg_overlap growing stale when we are
* indeed overlapping and hence not getting put to sleep, grow
* the avg_overlap on preemption.
*
* We use the average preemption runtime because that
* correlates to the amount of cache footprint a task can
* build up.
*/
update_avg(&prev->se.avg_overlap, runtime);
}
prev->sched_class->put_prev_task(rq, prev);
}
/*
* Pick up the highest-prio task:
*/
static inline struct task_struct *
pick_next_task(struct rq *rq, struct task_struct *prev)
pick_next_task(struct rq *rq)
{
const struct sched_class *class;
struct task_struct *p;
......@@ -4586,8 +4984,8 @@ asmlinkage void __sched schedule(void)
if (unlikely(!rq->nr_running))
idle_balance(cpu, rq);
prev->sched_class->put_prev_task(rq, prev);
next = pick_next_task(rq, prev);
put_prev_task(rq, prev);
next = pick_next_task(rq);
if (likely(prev != next)) {
sched_info_switch(prev, next);
......@@ -4642,7 +5040,7 @@ asmlinkage void __sched preempt_schedule(void)
* between schedule and now.
*/
barrier();
} while (unlikely(test_thread_flag(TIF_NEED_RESCHED)));
} while (need_resched());
}
EXPORT_SYMBOL(preempt_schedule);
......@@ -4671,7 +5069,7 @@ asmlinkage void __sched preempt_schedule_irq(void)
* between schedule and now.
*/
barrier();
} while (unlikely(test_thread_flag(TIF_NEED_RESCHED)));
} while (need_resched());
}
#endif /* CONFIG_PREEMPT */
......@@ -5145,7 +5543,7 @@ SYSCALL_DEFINE1(nice, int, increment)
if (increment > 40)
increment = 40;
nice = PRIO_TO_NICE(current->static_prio) + increment;
nice = TASK_NICE(current) + increment;
if (nice < -20)
nice = -20;
if (nice > 19)
......@@ -6423,7 +6821,7 @@ static void migrate_dead_tasks(unsigned int dead_cpu)
if (!rq->nr_running)
break;
update_rq_clock(rq);
next = pick_next_task(rq, rq->curr);
next = pick_next_task(rq);
if (!next)
break;
next->sched_class->put_prev_task(rq, next);
......@@ -8218,11 +8616,15 @@ static void init_rt_rq(struct rt_rq *rt_rq, struct rq *rq)
__set_bit(MAX_RT_PRIO, array->bitmap);
#if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
rt_rq->highest_prio = MAX_RT_PRIO;
rt_rq->highest_prio.curr = MAX_RT_PRIO;
#ifdef CONFIG_SMP
rt_rq->highest_prio.next = MAX_RT_PRIO;
#endif
#endif
#ifdef CONFIG_SMP
rt_rq->rt_nr_migratory = 0;
rt_rq->overloaded = 0;
plist_head_init(&rq->rt.pushable_tasks, &rq->lock);
#endif
rt_rq->rt_time = 0;
......@@ -9598,7 +10000,7 @@ static void cpuacct_charge(struct task_struct *tsk, u64 cputime)
struct cpuacct *ca;
int cpu;
if (!cpuacct_subsys.active)
if (unlikely(!cpuacct_subsys.active))
return;
cpu = task_cpu(tsk);
......
kernel/sched_clock.c
View file @ 831576fe
......@@ -24,11 +24,11 @@
* The clock: sched_clock_cpu() is monotonic per cpu, and should be somewhat
* consistent between cpus (never more than 2 jiffies difference).
*/
#include <linux/sched.h>
#include <linux/percpu.h>
#include <linux/spinlock.h>
#include <linux/ktime.h>
#include <linux/module.h>
#include <linux/percpu.h>
#include <linux/ktime.h>
#include <linux/sched.h>
/*
* Scheduler clock - returns current time in nanosec units.
......@@ -43,6 +43,7 @@ unsigned long long __attribute__((weak)) sched_clock(void)
static __read_mostly int sched_clock_running;
#ifdef CONFIG_HAVE_UNSTABLE_SCHED_CLOCK
__read_mostly int sched_clock_stable;
struct sched_clock_data {
/*
......@@ -87,7 +88,7 @@ void sched_clock_init(void)
}
/*
* min,max except they take wrapping into account
* min, max except they take wrapping into account
*/
static inline u64 wrap_min(u64 x, u64 y)
......@@ -111,15 +112,13 @@ static u64 __update_sched_clock(struct sched_clock_data *scd, u64 now)
s64 delta = now - scd->tick_raw;
u64 clock, min_clock, max_clock;
WARN_ON_ONCE(!irqs_disabled());
if (unlikely(delta < 0))
delta = 0;
/*
* scd->clock = clamp(scd->tick_gtod + delta,
* max(scd->tick_gtod, scd->clock),
* scd->tick_gtod + TICK_NSEC);
* max(scd->tick_gtod, scd->clock),
* scd->tick_gtod + TICK_NSEC);
*/
clock = scd->tick_gtod + delta;
......@@ -148,12 +147,13 @@ static void lock_double_clock(struct sched_clock_data *data1,
u64 sched_clock_cpu(int cpu)
{
struct sched_clock_data *scd = cpu_sdc(cpu);
u64 now, clock, this_clock, remote_clock;
struct sched_clock_data *scd;
if (unlikely(!sched_clock_running))
return 0ull;
if (sched_clock_stable)
return sched_clock();
scd = cpu_sdc(cpu);
WARN_ON_ONCE(!irqs_disabled());
now = sched_clock();
......@@ -195,14 +195,18 @@ u64 sched_clock_cpu(int cpu)
void sched_clock_tick(void)
{
struct sched_clock_data *scd = this_scd();
struct sched_clock_data *scd;
u64 now, now_gtod;
if (sched_clock_stable)
return;
if (unlikely(!sched_clock_running))
return;
WARN_ON_ONCE(!irqs_disabled());
scd = this_scd();
now_gtod = ktime_to_ns(ktime_get());
now = sched_clock();
......@@ -250,7 +254,7 @@ u64 sched_clock_cpu(int cpu)
return sched_clock();
}
#endif
#endif /* CONFIG_HAVE_UNSTABLE_SCHED_CLOCK */
unsigned long long cpu_clock(int cpu)
{
......
kernel/sched_debug.c
View file @ 831576fe
......@@ -272,7 +272,6 @@ static void print_cpu(struct seq_file *m, int cpu)
P(nr_switches);
P(nr_load_updates);
P(nr_uninterruptible);
SEQ_printf(m, " .%-30s: %lu\n", "jiffies", jiffies);
PN(next_balance);
P(curr->pid);
PN(clock);
......@@ -287,9 +286,6 @@ static void print_cpu(struct seq_file *m, int cpu)
#ifdef CONFIG_SCHEDSTATS
#define P(n) SEQ_printf(m, " .%-30s: %d\n", #n, rq->n);
P(yld_exp_empty);
P(yld_act_empty);
P(yld_both_empty);
P(yld_count);
P(sched_switch);
......@@ -314,7 +310,7 @@ static int sched_debug_show(struct seq_file *m, void *v)
u64 now = ktime_to_ns(ktime_get());
int cpu;
SEQ_printf(m, "Sched Debug Version: v0.08, %s %.*s\n",
SEQ_printf(m, "Sched Debug Version: v0.09, %s %.*s\n",
init_utsname()->release,
(int)strcspn(init_utsname()->version, " "),
init_utsname()->version);
......@@ -325,6 +321,7 @@ static int sched_debug_show(struct seq_file *m, void *v)
SEQ_printf(m, " .%-40s: %Ld\n", #x, (long long)(x))
#define PN(x) \
SEQ_printf(m, " .%-40s: %Ld.%06ld\n", #x, SPLIT_NS(x))
P(jiffies);
PN(sysctl_sched_latency);
PN(sysctl_sched_min_granularity);
PN(sysctl_sched_wakeup_granularity);
......@@ -397,6 +394,7 @@ void proc_sched_show_task(struct task_struct *p, struct seq_file *m)
PN(se.vruntime);
PN(se.sum_exec_runtime);
PN(se.avg_overlap);
PN(se.avg_wakeup);
nr_switches = p->nvcsw + p->nivcsw;
......
kernel/sched_fair.c
View file @ 831576fe
......@@ -1314,16 +1314,63 @@ static int select_task_rq_fair(struct task_struct *p, int sync)
}
#endif /* CONFIG_SMP */
static unsigned long wakeup_gran(struct sched_entity *se)
/*
* Adaptive granularity
*
* se->avg_wakeup gives the average time a task runs until it does a wakeup,
* with the limit of wakeup_gran -- when it never does a wakeup.
*
* So the smaller avg_wakeup is the faster we want this task to preempt,
* but we don't want to treat the preemptee unfairly and therefore allow it
* to run for at least the amount of time we'd like to run.
*
* NOTE: we use 2*avg_wakeup to increase the probability of actually doing one
*
* NOTE: we use *nr_running to scale with load, this nicely matches the
* degrading latency on load.
*/
static unsigned long
adaptive_gran(struct sched_entity *curr, struct sched_entity *se)
{
u64 this_run = curr->sum_exec_runtime - curr->prev_sum_exec_runtime;
u64 expected_wakeup = 2*se->avg_wakeup * cfs_rq_of(se)->nr_running;
u64 gran = 0;
if (this_run < expected_wakeup)
gran = expected_wakeup - this_run;
return min_t(s64, gran, sysctl_sched_wakeup_granularity);
}
static unsigned long
wakeup_gran(struct sched_entity *curr, struct sched_entity *se)
{
unsigned long gran = sysctl_sched_wakeup_granularity;
if (cfs_rq_of(curr)->curr && sched_feat(ADAPTIVE_GRAN))
gran = adaptive_gran(curr, se);
/*
* More easily preempt - nice tasks, while not making it harder for
* + nice tasks.
* Since its curr running now, convert the gran from real-time
* to virtual-time in his units.
*/
if (!sched_feat(ASYM_GRAN) || se->load.weight > NICE_0_LOAD)
gran = calc_delta_fair(sysctl_sched_wakeup_granularity, se);
if (sched_feat(ASYM_GRAN)) {
/*
* By using 'se' instead of 'curr' we penalize light tasks, so
* they get preempted easier. That is, if 'se' < 'curr' then
* the resulting gran will be larger, therefore penalizing the
* lighter, if otoh 'se' > 'curr' then the resulting gran will
* be smaller, again penalizing the lighter task.
*
* This is especially important for buddies when the leftmost
* task is higher priority than the buddy.
*/
if (unlikely(se->load.weight != NICE_0_LOAD))
gran = calc_delta_fair(gran, se);
} else {
if (unlikely(curr->load.weight != NICE_0_LOAD))
gran = calc_delta_fair(gran, curr);
}
return gran;
}
......@@ -1350,7 +1397,7 @@ wakeup_preempt_entity(struct sched_entity *curr, struct sched_entity *se)
if (vdiff <= 0)
return -1;
gran = wakeup_gran(curr);
gran = wakeup_gran(curr, se);
if (vdiff > gran)
return 1;
......
kernel/sched_features.h
View file @ 831576fe
SCHED_FEAT(NEW_FAIR_SLEEPERS, 1)
SCHED_FEAT(NORMALIZED_SLEEPER, 1)
SCHED_FEAT(NORMALIZED_SLEEPER, 0)
SCHED_FEAT(ADAPTIVE_GRAN, 1)
SCHED_FEAT(WAKEUP_PREEMPT, 1)
SCHED_FEAT(START_DEBIT, 1)
SCHED_FEAT(AFFINE_WAKEUPS, 1)
......
kernel/sched_rt.c
View file @ 831576fe
......@@ -3,6 +3,40 @@
* policies)
*/
static inline struct task_struct *rt_task_of(struct sched_rt_entity *rt_se)
{
return container_of(rt_se, struct task_struct, rt);
}
#ifdef CONFIG_RT_GROUP_SCHED
static inline struct rq *rq_of_rt_rq(struct rt_rq *rt_rq)
{
return rt_rq->rq;
}
static inline struct rt_rq *rt_rq_of_se(struct sched_rt_entity *rt_se)
{
return rt_se->rt_rq;
}
#else /* CONFIG_RT_GROUP_SCHED */
static inline struct rq *rq_of_rt_rq(struct rt_rq *rt_rq)
{
return container_of(rt_rq, struct rq, rt);
}
static inline struct rt_rq *rt_rq_of_se(struct sched_rt_entity *rt_se)
{
struct task_struct *p = rt_task_of(rt_se);
struct rq *rq = task_rq(p);
return &rq->rt;
}
#endif /* CONFIG_RT_GROUP_SCHED */
#ifdef CONFIG_SMP
static inline int rt_overloaded(struct rq *rq)
......@@ -37,25 +71,69 @@ static inline void rt_clear_overload(struct rq *rq)
cpumask_clear_cpu(rq->cpu, rq->rd->rto_mask);
}
static void update_rt_migration(struct rq *rq)
static void update_rt_migration(struct rt_rq *rt_rq)
{
if (rq->rt.rt_nr_migratory && (rq->rt.rt_nr_running > 1)) {
if (!rq->rt.overloaded) {
rt_set_overload(rq);
rq->rt.overloaded = 1;
if (rt_rq->rt_nr_migratory && (rt_rq->rt_nr_running > 1)) {
if (!rt_rq->overloaded) {
rt_set_overload(rq_of_rt_rq(rt_rq));
rt_rq->overloaded = 1;
}
} else if (rq->rt.overloaded) {
rt_clear_overload(rq);
rq->rt.overloaded = 0;
} else if (rt_rq->overloaded) {
rt_clear_overload(rq_of_rt_rq(rt_rq));
rt_rq->overloaded = 0;
}
}
#endif /* CONFIG_SMP */
static inline struct task_struct *rt_task_of(struct sched_rt_entity *rt_se)
static void inc_rt_migration(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
{
if (rt_se->nr_cpus_allowed > 1)
rt_rq->rt_nr_migratory++;
update_rt_migration(rt_rq);
}
static void dec_rt_migration(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
{
if (rt_se->nr_cpus_allowed > 1)
rt_rq->rt_nr_migratory--;
update_rt_migration(rt_rq);
}
static void enqueue_pushable_task(struct rq *rq, struct task_struct *p)
{
plist_del(&p->pushable_tasks, &rq->rt.pushable_tasks);
plist_node_init(&p->pushable_tasks, p->prio);
plist_add(&p->pushable_tasks, &rq->rt.pushable_tasks);
}
static void dequeue_pushable_task(struct rq *rq, struct task_struct *p)
{
plist_del(&p->pushable_tasks, &rq->rt.pushable_tasks);
}
#else
static inline void enqueue_pushable_task(struct rq *rq, struct task_struct *p)
{
return container_of(rt_se, struct task_struct, rt);
}
static inline void dequeue_pushable_task(struct rq *rq, struct task_struct *p)
{
}
static inline
void inc_rt_migration(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
{
}
static inline
void dec_rt_migration(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
{
}
#endif /* CONFIG_SMP */
static inline int on_rt_rq(struct sched_rt_entity *rt_se)
{
return !list_empty(&rt_se->run_list);
......@@ -79,16 +157,6 @@ static inline u64 sched_rt_period(struct rt_rq *rt_rq)
#define for_each_leaf_rt_rq(rt_rq, rq) \
list_for_each_entry_rcu(rt_rq, &rq->leaf_rt_rq_list, leaf_rt_rq_list)
static inline struct rq *rq_of_rt_rq(struct rt_rq *rt_rq)
{
return rt_rq->rq;
}
static inline struct rt_rq *rt_rq_of_se(struct sched_rt_entity *rt_se)
{
return rt_se->rt_rq;
}
#define for_each_sched_rt_entity(rt_se) \
for (; rt_se; rt_se = rt_se->parent)
......@@ -108,7 +176,7 @@ static void sched_rt_rq_enqueue(struct rt_rq *rt_rq)
if (rt_rq->rt_nr_running) {
if (rt_se && !on_rt_rq(rt_se))
enqueue_rt_entity(rt_se);
if (rt_rq->highest_prio < curr->prio)
if (rt_rq->highest_prio.curr < curr->prio)
resched_task(curr);
}
}
......@@ -176,19 +244,6 @@ static inline u64 sched_rt_period(struct rt_rq *rt_rq)
#define for_each_leaf_rt_rq(rt_rq, rq) \
for (rt_rq = &rq->rt; rt_rq; rt_rq = NULL)
static inline struct rq *rq_of_rt_rq(struct rt_rq *rt_rq)
{
return container_of(rt_rq, struct rq, rt);
}
static inline struct rt_rq *rt_rq_of_se(struct sched_rt_entity *rt_se)
{
struct task_struct *p = rt_task_of(rt_se);
struct rq *rq = task_rq(p);
return &rq->rt;
}
#define for_each_sched_rt_entity(rt_se) \
for (; rt_se; rt_se = NULL)
......@@ -473,7 +528,7 @@ static inline int rt_se_prio(struct sched_rt_entity *rt_se)
struct rt_rq *rt_rq = group_rt_rq(rt_se);
if (rt_rq)
return rt_rq->highest_prio;
return rt_rq->highest_prio.curr;
#endif
return rt_task_of(rt_se)->prio;
......@@ -547,91 +602,174 @@ static void update_curr_rt(struct rq *rq)
}
}
static inline
void inc_rt_tasks(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
#if defined CONFIG_SMP
static struct task_struct *pick_next_highest_task_rt(struct rq *rq, int cpu);
static inline int next_prio(struct rq *rq)
{
WARN_ON(!rt_prio(rt_se_prio(rt_se)));
rt_rq->rt_nr_running++;
#if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
if (rt_se_prio(rt_se) < rt_rq->highest_prio) {
#ifdef CONFIG_SMP
struct rq *rq = rq_of_rt_rq(rt_rq);
#endif
struct task_struct *next = pick_next_highest_task_rt(rq, rq->cpu);
if (next && rt_prio(next->prio))
return next->prio;
else
return MAX_RT_PRIO;
}
static void
inc_rt_prio_smp(struct rt_rq *rt_rq, int prio, int prev_prio)
{
struct rq *rq = rq_of_rt_rq(rt_rq);
if (prio < prev_prio) {
/*
* If the new task is higher in priority than anything on the
* run-queue, we know that the previous high becomes our
* next-highest.
*/
rt_rq->highest_prio.next = prev_prio;
rt_rq->highest_prio = rt_se_prio(rt_se);
#ifdef CONFIG_SMP
if (rq->online)
cpupri_set(&rq->rd->cpupri, rq->cpu,
rt_se_prio(rt_se));
#endif
}
#endif
#ifdef CONFIG_SMP
if (rt_se->nr_cpus_allowed > 1) {
struct rq *rq = rq_of_rt_rq(rt_rq);
cpupri_set(&rq->rd->cpupri, rq->cpu, prio);
rq->rt.rt_nr_migratory++;
}
} else if (prio == rt_rq->highest_prio.curr)
/*
* If the next task is equal in priority to the highest on
* the run-queue, then we implicitly know that the next highest
* task cannot be any lower than current
*/
rt_rq->highest_prio.next = prio;
else if (prio < rt_rq->highest_prio.next)
/*
* Otherwise, we need to recompute next-highest
*/
rt_rq->highest_prio.next = next_prio(rq);
}
update_rt_migration(rq_of_rt_rq(rt_rq));
#endif
#ifdef CONFIG_RT_GROUP_SCHED
if (rt_se_boosted(rt_se))
rt_rq->rt_nr_boosted++;
static void
dec_rt_prio_smp(struct rt_rq *rt_rq, int prio, int prev_prio)
{
struct rq *rq = rq_of_rt_rq(rt_rq);
if (rt_rq->tg)
start_rt_bandwidth(&rt_rq->tg->rt_bandwidth);
#else
start_rt_bandwidth(&def_rt_bandwidth);
#endif
if (rt_rq->rt_nr_running && (prio <= rt_rq->highest_prio.next))
rt_rq->highest_prio.next = next_prio(rq);
if (rq->online && rt_rq->highest_prio.curr != prev_prio)
cpupri_set(&rq->rd->cpupri, rq->cpu, rt_rq->highest_prio.curr);
}
#else /* CONFIG_SMP */
static inline
void dec_rt_tasks(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
{
#ifdef CONFIG_SMP
int highest_prio = rt_rq->highest_prio;
#endif
void inc_rt_prio_smp(struct rt_rq *rt_rq, int prio, int prev_prio) {}
static inline
void dec_rt_prio_smp(struct rt_rq *rt_rq, int prio, int prev_prio) {}
#endif /* CONFIG_SMP */
WARN_ON(!rt_prio(rt_se_prio(rt_se)));
WARN_ON(!rt_rq->rt_nr_running);
rt_rq->rt_nr_running--;
#if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
static void
inc_rt_prio(struct rt_rq *rt_rq, int prio)
{
int prev_prio = rt_rq->highest_prio.curr;
if (prio < prev_prio)
rt_rq->highest_prio.curr = prio;
inc_rt_prio_smp(rt_rq, prio, prev_prio);
}
static void
dec_rt_prio(struct rt_rq *rt_rq, int prio)
{
int prev_prio = rt_rq->highest_prio.curr;
if (rt_rq->rt_nr_running) {
struct rt_prio_array *array;
WARN_ON(rt_se_prio(rt_se) < rt_rq->highest_prio);
if (rt_se_prio(rt_se) == rt_rq->highest_prio) {
/* recalculate */
array = &rt_rq->active;
rt_rq->highest_prio =
WARN_ON(prio < prev_prio);
/*
* This may have been our highest task, and therefore
* we may have some recomputation to do
*/
if (prio == prev_prio) {
struct rt_prio_array *array = &rt_rq->active;
rt_rq->highest_prio.curr =
sched_find_first_bit(array->bitmap);
} /* otherwise leave rq->highest prio alone */
}
} else
rt_rq->highest_prio = MAX_RT_PRIO;
#endif
#ifdef CONFIG_SMP
if (rt_se->nr_cpus_allowed > 1) {
struct rq *rq = rq_of_rt_rq(rt_rq);
rq->rt.rt_nr_migratory--;
}
rt_rq->highest_prio.curr = MAX_RT_PRIO;
if (rt_rq->highest_prio != highest_prio) {
struct rq *rq = rq_of_rt_rq(rt_rq);
dec_rt_prio_smp(rt_rq, prio, prev_prio);
}
if (rq->online)
cpupri_set(&rq->rd->cpupri, rq->cpu,
rt_rq->highest_prio);
}
#else
static inline void inc_rt_prio(struct rt_rq *rt_rq, int prio) {}
static inline void dec_rt_prio(struct rt_rq *rt_rq, int prio) {}
#endif /* CONFIG_SMP || CONFIG_RT_GROUP_SCHED */
update_rt_migration(rq_of_rt_rq(rt_rq));
#endif /* CONFIG_SMP */
#ifdef CONFIG_RT_GROUP_SCHED
static void
inc_rt_group(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
{
if (rt_se_boosted(rt_se))
rt_rq->rt_nr_boosted++;
if (rt_rq->tg)
start_rt_bandwidth(&rt_rq->tg->rt_bandwidth);
}
static void
dec_rt_group(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
{
if (rt_se_boosted(rt_se))
rt_rq->rt_nr_boosted--;
WARN_ON(!rt_rq->rt_nr_running && rt_rq->rt_nr_boosted);
#endif
}
#else /* CONFIG_RT_GROUP_SCHED */
static void
inc_rt_group(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
{
start_rt_bandwidth(&def_rt_bandwidth);
}
static inline
void dec_rt_group(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq) {}
#endif /* CONFIG_RT_GROUP_SCHED */
static inline
void inc_rt_tasks(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
{
int prio = rt_se_prio(rt_se);
WARN_ON(!rt_prio(prio));
rt_rq->rt_nr_running++;
inc_rt_prio(rt_rq, prio);
inc_rt_migration(rt_se, rt_rq);
inc_rt_group(rt_se, rt_rq);
}
static inline
void dec_rt_tasks(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
{
WARN_ON(!rt_prio(rt_se_prio(rt_se)));
WARN_ON(!rt_rq->rt_nr_running);
rt_rq->rt_nr_running--;
dec_rt_prio(rt_rq, rt_se_prio(rt_se));
dec_rt_migration(rt_se, rt_rq);
dec_rt_group(rt_se, rt_rq);
}
static void __enqueue_rt_entity(struct sched_rt_entity *rt_se)
......@@ -718,6 +856,9 @@ static void enqueue_task_rt(struct rq *rq, struct task_struct *p, int wakeup)
enqueue_rt_entity(rt_se);
if (!task_current(rq, p) && p->rt.nr_cpus_allowed > 1)
enqueue_pushable_task(rq, p);
inc_cpu_load(rq, p->se.load.weight);
}
......@@ -728,6 +869,8 @@ static void dequeue_task_rt(struct rq *rq, struct task_struct *p, int sleep)
update_curr_rt(rq);
dequeue_rt_entity(rt_se);
dequeue_pushable_task(rq, p);
dec_cpu_load(rq, p->se.load.weight);
}
......@@ -878,7 +1021,7 @@ static struct sched_rt_entity *pick_next_rt_entity(struct rq *rq,
return next;
}
static struct task_struct *pick_next_task_rt(struct rq *rq)
static struct task_struct *_pick_next_task_rt(struct rq *rq)
{
struct sched_rt_entity *rt_se;
struct task_struct *p;
......@@ -900,6 +1043,18 @@ static struct task_struct *pick_next_task_rt(struct rq *rq)
p = rt_task_of(rt_se);
p->se.exec_start = rq->clock;
return p;
}
static struct task_struct *pick_next_task_rt(struct rq *rq)
{
struct task_struct *p = _pick_next_task_rt(rq);
/* The running task is never eligible for pushing */
if (p)
dequeue_pushable_task(rq, p);
return p;
}
......@@ -907,6 +1062,13 @@ static void put_prev_task_rt(struct rq *rq, struct task_struct *p)
{
update_curr_rt(rq);
p->se.exec_start = 0;
/*
* The previous task needs to be made eligible for pushing
* if it is still active
*/
if (p->se.on_rq && p->rt.nr_cpus_allowed > 1)
enqueue_pushable_task(rq, p);
}
#ifdef CONFIG_SMP
......@@ -1072,7 +1234,7 @@ static struct rq *find_lock_lowest_rq(struct task_struct *task, struct rq *rq)
}
/* If this rq is still suitable use it. */
if (lowest_rq->rt.highest_prio > task->prio)
if (lowest_rq->rt.highest_prio.curr > task->prio)
break;
/* try again */
......@@ -1083,6 +1245,31 @@ static struct rq *find_lock_lowest_rq(struct task_struct *task, struct rq *rq)
return lowest_rq;
}
static inline int has_pushable_tasks(struct rq *rq)
{
return !plist_head_empty(&rq->rt.pushable_tasks);
}
static struct task_struct *pick_next_pushable_task(struct rq *rq)
{
struct task_struct *p;
if (!has_pushable_tasks(rq))
return NULL;
p = plist_first_entry(&rq->rt.pushable_tasks,
struct task_struct, pushable_tasks);
BUG_ON(rq->cpu != task_cpu(p));
BUG_ON(task_current(rq, p));
BUG_ON(p->rt.nr_cpus_allowed <= 1);
BUG_ON(!p->se.on_rq);
BUG_ON(!rt_task(p));
return p;
}
/*
* If the current CPU has more than one RT task, see if the non
* running task can migrate over to a CPU that is running a task
......@@ -1092,13 +1279,11 @@ static int push_rt_task(struct rq *rq)
{
struct task_struct *next_task;
struct rq *lowest_rq;
int ret = 0;
int paranoid = RT_MAX_TRIES;
if (!rq->rt.overloaded)
return 0;
next_task = pick_next_highest_task_rt(rq, -1);
next_task = pick_next_pushable_task(rq);
if (!next_task)
return 0;
......@@ -1127,16 +1312,34 @@ static int push_rt_task(struct rq *rq)
struct task_struct *task;
/*
* find lock_lowest_rq releases rq->lock
* so it is possible that next_task has changed.
* If it has, then try again.
* so it is possible that next_task has migrated.
*
* We need to make sure that the task is still on the same
* run-queue and is also still the next task eligible for
* pushing.
*/
task = pick_next_highest_task_rt(rq, -1);
if (unlikely(task != next_task) && task && paranoid--) {
put_task_struct(next_task);
next_task = task;
goto retry;
task = pick_next_pushable_task(rq);
if (task_cpu(next_task) == rq->cpu && task == next_task) {
/*
* If we get here, the task hasnt moved at all, but
* it has failed to push. We will not try again,
* since the other cpus will pull from us when they
* are ready.
*/
dequeue_pushable_task(rq, next_task);
goto out;
}
goto out;
if (!task)
/* No more tasks, just exit */
goto out;
/*
* Something has shifted, try again.
*/
put_task_struct(next_task);
next_task = task;
goto retry;
}
deactivate_task(rq, next_task, 0);
......@@ -1147,23 +1350,12 @@ static int push_rt_task(struct rq *rq)
double_unlock_balance(rq, lowest_rq);
ret = 1;
out:
put_task_struct(next_task);
return ret;
return 1;
}
/*
* TODO: Currently we just use the second highest prio task on
* the queue, and stop when it can't migrate (or there's
* no more RT tasks). There may be a case where a lower
* priority RT task has a different affinity than the
* higher RT task. In this case the lower RT task could
* possibly be able to migrate where as the higher priority
* RT task could not. We currently ignore this issue.
* Enhancements are welcome!
*/
static void push_rt_tasks(struct rq *rq)
{
/* push_rt_task will return true if it moved an RT */
......@@ -1174,33 +1366,35 @@ static void push_rt_tasks(struct rq *rq)
static int pull_rt_task(struct rq *this_rq)
{
int this_cpu = this_rq->cpu, ret = 0, cpu;
struct task_struct *p, *next;
struct task_struct *p;
struct rq *src_rq;
if (likely(!rt_overloaded(this_rq)))
return 0;
next = pick_next_task_rt(this_rq);
for_each_cpu(cpu, this_rq->rd->rto_mask) {
if (this_cpu == cpu)
continue;
src_rq = cpu_rq(cpu);
/*
* Don't bother taking the src_rq->lock if the next highest
* task is known to be lower-priority than our current task.
* This may look racy, but if this value is about to go
* logically higher, the src_rq will push this task away.
* And if its going logically lower, we do not care
*/
if (src_rq->rt.highest_prio.next >=
this_rq->rt.highest_prio.curr)
continue;
/*
* We can potentially drop this_rq's lock in
* double_lock_balance, and another CPU could
* steal our next task - hence we must cause
* the caller to recalculate the next task
* in that case:
* alter this_rq
*/
if (double_lock_balance(this_rq, src_rq)) {
struct task_struct *old_next = next;
next = pick_next_task_rt(this_rq);
if (next != old_next)
ret = 1;
}
double_lock_balance(this_rq, src_rq);
/*
* Are there still pullable RT tasks?
......@@ -1214,7 +1408,7 @@ static int pull_rt_task(struct rq *this_rq)
* Do we have an RT task that preempts
* the to-be-scheduled task?
*/
if (p && (!next || (p->prio < next->prio))) {
if (p && (p->prio < this_rq->rt.highest_prio.curr)) {
WARN_ON(p == src_rq->curr);
WARN_ON(!p->se.on_rq);
......@@ -1224,12 +1418,9 @@ static int pull_rt_task(struct rq *this_rq)
* This is just that p is wakeing up and hasn't
* had a chance to schedule. We only pull
* p if it is lower in priority than the
* current task on the run queue or
* this_rq next task is lower in prio than
* the current task on that rq.
* current task on the run queue
*/
if (p->prio < src_rq->curr->prio ||
(next && next->prio < src_rq->curr->prio))
if (p->prio < src_rq->curr->prio)
goto skip;
ret = 1;
......@@ -1242,13 +1433,7 @@ static int pull_rt_task(struct rq *this_rq)
* case there's an even higher prio task
* in another runqueue. (low likelyhood
* but possible)
*
* Update next so that we won't pick a task
* on another cpu with a priority lower (or equal)
* than the one we just picked.
*/
next = p;
}
skip:
double_unlock_balance(this_rq, src_rq);
......@@ -1260,24 +1445,27 @@ static int pull_rt_task(struct rq *this_rq)
static void pre_schedule_rt(struct rq *rq, struct task_struct *prev)
{
/* Try to pull RT tasks here if we lower this rq's prio */
if (unlikely(rt_task(prev)) && rq->rt.highest_prio > prev->prio)
if (unlikely(rt_task(prev)) && rq->rt.highest_prio.curr > prev->prio)
pull_rt_task(rq);
}
/*
* assumes rq->lock is held
*/
static int needs_post_schedule_rt(struct rq *rq)
{
return has_pushable_tasks(rq);
}
static void post_schedule_rt(struct rq *rq)
{
/*
* If we have more than one rt_task queued, then
* see if we can push the other rt_tasks off to other CPUS.
* Note we may release the rq lock, and since
* the lock was owned by prev, we need to release it
* first via finish_lock_switch and then reaquire it here.
* This is only called if needs_post_schedule_rt() indicates that
* we need to push tasks away
*/
if (unlikely(rq->rt.overloaded)) {
spin_lock_irq(&rq->lock);
push_rt_tasks(rq);
spin_unlock_irq(&rq->lock);
}
spin_lock_irq(&rq->lock);
push_rt_tasks(rq);
spin_unlock_irq(&rq->lock);
}
/*
......@@ -1288,7 +1476,8 @@ static void task_wake_up_rt(struct rq *rq, struct task_struct *p)
{
if (!task_running(rq, p) &&
!test_tsk_need_resched(rq->curr) &&
rq->rt.overloaded)
has_pushable_tasks(rq) &&
p->rt.nr_cpus_allowed > 1)
push_rt_tasks(rq);
}
......@@ -1324,6 +1513,24 @@ static void set_cpus_allowed_rt(struct task_struct *p,
if (p->se.on_rq && (weight != p->rt.nr_cpus_allowed)) {
struct rq *rq = task_rq(p);
if (!task_current(rq, p)) {
/*
* Make sure we dequeue this task from the pushable list
* before going further. It will either remain off of
* the list because we are no longer pushable, or it
* will be requeued.
*/
if (p->rt.nr_cpus_allowed > 1)
dequeue_pushable_task(rq, p);
/*
* Requeue if our weight is changing and still > 1
*/
if (weight > 1)
enqueue_pushable_task(rq, p);
}
if ((p->rt.nr_cpus_allowed <= 1) && (weight > 1)) {
rq->rt.rt_nr_migratory++;
} else if ((p->rt.nr_cpus_allowed > 1) && (weight <= 1)) {
......@@ -1331,7 +1538,7 @@ static void set_cpus_allowed_rt(struct task_struct *p,
rq->rt.rt_nr_migratory--;
}
update_rt_migration(rq);
update_rt_migration(&rq->rt);
}
cpumask_copy(&p->cpus_allowed, new_mask);
......@@ -1346,7 +1553,7 @@ static void rq_online_rt(struct rq *rq)
__enable_runtime(rq);
cpupri_set(&rq->rd->cpupri, rq->cpu, rq->rt.highest_prio);
cpupri_set(&rq->rd->cpupri, rq->cpu, rq->rt.highest_prio.curr);
}
/* Assumes rq->lock is held */
......@@ -1438,7 +1645,7 @@ static void prio_changed_rt(struct rq *rq, struct task_struct *p,
* can release the rq lock and p could migrate.
* Only reschedule if p is still on the same runqueue.
*/
if (p->prio > rq->rt.highest_prio && rq->curr == p)
if (p->prio > rq->rt.highest_prio.curr && rq->curr == p)
resched_task(p);
#else
/* For UP simply resched on drop of prio */
......@@ -1509,6 +1716,9 @@ static void set_curr_task_rt(struct rq *rq)
struct task_struct *p = rq->curr;
p->se.exec_start = rq->clock;
/* The running task is never eligible for pushing */
dequeue_pushable_task(rq, p);
}
static const struct sched_class rt_sched_class = {
......@@ -1531,6 +1741,7 @@ static const struct sched_class rt_sched_class = {
.rq_online = rq_online_rt,
.rq_offline = rq_offline_rt,
.pre_schedule = pre_schedule_rt,
.needs_post_schedule = needs_post_schedule_rt,
.post_schedule = post_schedule_rt,
.task_wake_up = task_wake_up_rt,
.switched_from = switched_from_rt,
......
kernel/sched_stats.h
View file @ 831576fe
......@@ -4,7 +4,7 @@
* bump this up when changing the output format or the meaning of an existing
* format, so that tools can adapt (or abort)
*/
#define SCHEDSTAT_VERSION 14
#define SCHEDSTAT_VERSION 15
static int show_schedstat(struct seq_file *seq, void *v)
{
......@@ -26,9 +26,8 @@ static int show_schedstat(struct seq_file *seq, void *v)
/* runqueue-specific stats */
seq_printf(seq,
"cpu%d %u %u %u %u %u %u %u %u %u %llu %llu %lu",
cpu, rq->yld_both_empty,
rq->yld_act_empty, rq->yld_exp_empty, rq->yld_count,
"cpu%d %u %u %u %u %u %u %llu %llu %lu",
cpu, rq->yld_count,
rq->sched_switch, rq->sched_count, rq->sched_goidle,
rq->ttwu_count, rq->ttwu_local,
rq->rq_cpu_time,
......
lib/Kconfig
View file @ 831576fe
......@@ -136,12 +136,6 @@ config TEXTSEARCH_BM
config TEXTSEARCH_FSM
tristate
#
# plist support is select#ed if needed
#
config PLIST
boolean
config HAS_IOMEM
boolean
depends on !NO_IOMEM
......
lib/Makefile
View file @ 831576fe
......@@ -11,7 +11,8 @@ lib-y := ctype.o string.o vsprintf.o cmdline.o \
rbtree.o radix-tree.o dump_stack.o \
idr.o int_sqrt.o extable.o prio_tree.o \
sha1.o irq_regs.o reciprocal_div.o argv_split.o \
proportions.o prio_heap.o ratelimit.o show_mem.o is_single_threaded.o
proportions.o prio_heap.o ratelimit.o show_mem.o \
is_single_threaded.o plist.o
lib-$(CONFIG_MMU) += ioremap.o
lib-$(CONFIG_SMP) += cpumask.o
......@@ -40,7 +41,6 @@ lib-$(CONFIG_GENERIC_FIND_NEXT_BIT) += find_next_bit.o
lib-$(CONFIG_GENERIC_FIND_LAST_BIT) += find_last_bit.o
obj-$(CONFIG_GENERIC_HWEIGHT) += hweight.o
obj-$(CONFIG_LOCK_KERNEL) += kernel_lock.o
obj-$(CONFIG_PLIST) += plist.o
obj-$(CONFIG_DEBUG_PREEMPT) += smp_processor_id.o
obj-$(CONFIG_DEBUG_LIST) += list_debug.o
obj-$(CONFIG_DEBUG_OBJECTS) += debugobjects.o
......
lib/kernel_lock.c
View file @ 831576fe
......@@ -39,7 +39,7 @@ static __cacheline_aligned_in_smp DEFINE_SPINLOCK(kernel_flag);
int __lockfunc __reacquire_kernel_lock(void)
{
while (!_raw_spin_trylock(&kernel_flag)) {
if (test_thread_flag(TIF_NEED_RESCHED))
if (need_resched())
return -EAGAIN;
cpu_relax();
}
......
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