The patch titled
PI-futex: scheduler support for PI
has been removed from the -mm tree. Its filename is
pi-futex-scheduler-support-for-pi.patch
This patch was probably dropped from -mm because
it has now been merged into a subsystem tree or
into Linus's tree, or because it was folded into
its parent patch in the -mm tree.
------------------------------------------------------
Subject: PI-futex: scheduler support for PI
From: Ingo Molnar <mingo@xxxxxxx>
Add framework to boost/unboost the priority of RT tasks.
This consists of:
- caching the 'normal' priority in ->normal_prio
- providing a functions to set/get the priority of the task
- make sched_setscheduler() aware of boosting
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Arjan van de Ven <arjan@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
include/linux/init_task.h | 1
include/linux/sched.h | 19 ++++-
kernel/sched.c | 136 +++++++++++++++++++++++++++++++-----
3 files changed, 138 insertions(+), 18 deletions(-)
diff -puN include/linux/init_task.h~pi-futex-scheduler-support-for-pi include/linux/init_task.h
--- devel/include/linux/init_task.h~pi-futex-scheduler-support-for-pi 2006-05-19 16:01:32.000000000 -0700
+++ devel-akpm/include/linux/init_task.h 2006-05-19 16:01:32.000000000 -0700
@@ -87,6 +87,7 @@ extern struct group_info init_groups;
.lock_depth = -1, \
.prio = MAX_PRIO-20, \
.static_prio = MAX_PRIO-20, \
+ .normal_prio = MAX_PRIO-20, \
.policy = SCHED_NORMAL, \
.cpus_allowed = CPU_MASK_ALL, \
.mm = NULL, \
diff -puN include/linux/sched.h~pi-futex-scheduler-support-for-pi include/linux/sched.h
--- devel/include/linux/sched.h~pi-futex-scheduler-support-for-pi 2006-05-19 16:01:32.000000000 -0700
+++ devel-akpm/include/linux/sched.h 2006-05-19 16:01:32.000000000 -0700
@@ -484,7 +484,8 @@ struct signal_struct {
#define MAX_PRIO (MAX_RT_PRIO + 40)
-#define rt_task(p) (unlikely((p)->prio < MAX_RT_PRIO))
+#define rt_prio(prio) unlikely((prio) < MAX_RT_PRIO)
+#define rt_task(p) rt_prio((p)->prio)
#define batch_task(p) (unlikely((p)->policy == SCHED_BATCH))
/*
@@ -769,7 +770,7 @@ struct task_struct {
#endif
#endif
int load_weight; /* for niceness load balancing purposes */
- int prio, static_prio;
+ int prio, static_prio, normal_prio;
struct list_head run_list;
prio_array_t *array;
@@ -898,6 +899,9 @@ struct task_struct {
/* Protection of proc_dentry: nesting proc_lock, dcache_lock, write_lock_irq(&tasklist_lock); */
spinlock_t proc_lock;
+ /* Protection of the PI data structures: */
+ spinlock_t pi_lock;
+
#ifdef CONFIG_DEBUG_MUTEXES
/* mutex deadlock detection */
struct mutex_waiter *blocked_on;
@@ -1069,6 +1073,17 @@ static inline void idle_task_exit(void)
#endif
extern void sched_idle_next(void);
+
+#ifdef CONFIG_RT_MUTEXES
+extern int rt_mutex_getprio(task_t *p);
+extern void rt_mutex_setprio(task_t *p, int prio);
+#else
+static inline int rt_mutex_getprio(task_t *p)
+{
+ return p->normal_prio;
+}
+#endif
+
extern void set_user_nice(task_t *p, long nice);
extern int task_prio(const task_t *p);
extern int task_nice(const task_t *p);
diff -puN kernel/sched.c~pi-futex-scheduler-support-for-pi kernel/sched.c
--- devel/kernel/sched.c~pi-futex-scheduler-support-for-pi 2006-05-19 16:01:32.000000000 -0700
+++ devel-akpm/kernel/sched.c 2006-05-19 16:01:32.000000000 -0700
@@ -666,7 +666,7 @@ static inline void enqueue_task_head(str
}
/*
- * effective_prio - return the priority that is based on the static
+ * __normal_prio - return the priority that is based on the static
* priority but is modified by bonuses/penalties.
*
* We scale the actual sleep average [0 .... MAX_SLEEP_AVG]
@@ -679,13 +679,11 @@ static inline void enqueue_task_head(str
*
* Both properties are important to certain workloads.
*/
-static int effective_prio(task_t *p)
+
+static inline int __normal_prio(task_t *p)
{
int bonus, prio;
- if (rt_task(p))
- return p->prio;
-
bonus = CURRENT_BONUS(p) - MAX_BONUS / 2;
prio = p->static_prio - bonus;
@@ -801,6 +799,44 @@ static inline void dec_nr_running(task_t
}
/*
+ * Calculate the expected normal priority: i.e. priority
+ * without taking RT-inheritance into account. Might be
+ * boosted by interactivity modifiers. Changes upon fork,
+ * setprio syscalls, and whenever the interactivity
+ * estimator recalculates.
+ */
+static inline int normal_prio(task_t *p)
+{
+ int prio;
+
+ if (p->policy != SCHED_NORMAL && p->policy != SCHED_BATCH)
+ prio = MAX_RT_PRIO-1 - p->rt_priority;
+ else
+ prio = __normal_prio(p);
+ return prio;
+}
+
+/*
+ * Calculate the current priority, i.e. the priority
+ * taken into account by the scheduler. This value might
+ * be boosted by RT tasks, or might be boosted by
+ * interactivity modifiers. Will be RT if the task got
+ * RT-boosted. If not then it returns p->normal_prio.
+ */
+static int effective_prio(task_t *p)
+{
+ p->normal_prio = normal_prio(p);
+ /*
+ * If we are RT tasks or we were boosted to RT priority,
+ * keep the priority unchanged. Otherwise, update priority
+ * to the normal priority:
+ */
+ if (!rt_prio(p->prio))
+ return p->normal_prio;
+ return p->prio;
+}
+
+/*
* __activate_task - move a task to the runqueue.
*/
static void __activate_task(task_t *p, runqueue_t *rq)
@@ -822,6 +858,10 @@ static inline void __activate_idle_task(
inc_nr_running(p, rq);
}
+/*
+ * Recalculate p->normal_prio and p->prio after having slept,
+ * updating the sleep-average too:
+ */
static int recalc_task_prio(task_t *p, unsigned long long now)
{
/* Caller must always ensure 'now >= p->timestamp' */
@@ -1587,6 +1627,7 @@ void fastcall wake_up_new_task(task_t *p
__activate_task(p, rq);
else {
p->prio = current->prio;
+ p->normal_prio = current->normal_prio;
list_add_tail(&p->run_list, ¤t->run_list);
p->array = current->array;
p->array->nr_active++;
@@ -3700,6 +3741,59 @@ long fastcall __sched sleep_on_timeout(w
EXPORT_SYMBOL(sleep_on_timeout);
+#ifdef CONFIG_RT_MUTEXES
+
+/*
+ * rt_mutex_setprio - set the current priority of a task
+ * @p: task
+ * @prio: prio value (kernel-internal form)
+ *
+ * This function changes the 'effective' priority of a task. It does
+ * not touch ->normal_prio like __setscheduler().
+ *
+ * Used by the rt_mutex code to implement priority inheritance logic.
+ */
+void rt_mutex_setprio(task_t *p, int prio)
+{
+ unsigned long flags;
+ prio_array_t *array;
+ runqueue_t *rq;
+ int oldprio;
+
+ BUG_ON(prio < 0 || prio > MAX_PRIO);
+
+ rq = task_rq_lock(p, &flags);
+
+ oldprio = p->prio;
+ array = p->array;
+ if (array)
+ dequeue_task(p, array);
+ p->prio = prio;
+
+ if (array) {
+ /*
+ * If changing to an RT priority then queue it
+ * in the active array!
+ */
+ if (rt_task(p))
+ array = rq->active;
+ enqueue_task(p, array);
+ /*
+ * Reschedule if we are currently running on this runqueue and
+ * our priority decreased, or if we are not currently running on
+ * this runqueue and our priority is higher than the current's
+ */
+ if (task_running(rq, p)) {
+ if (p->prio > oldprio)
+ resched_task(rq->curr);
+ } else if (TASK_PREEMPTS_CURR(p, rq))
+ resched_task(rq->curr);
+ }
+ task_rq_unlock(rq, &flags);
+}
+
+#endif
+
void set_user_nice(task_t *p, long nice)
{
unsigned long flags;
@@ -3865,16 +3959,16 @@ static void __setscheduler(struct task_s
BUG_ON(p->array);
p->policy = policy;
p->rt_priority = prio;
- if (policy != SCHED_NORMAL && policy != SCHED_BATCH) {
- p->prio = MAX_RT_PRIO-1 - p->rt_priority;
- } else {
- p->prio = p->static_prio;
- /*
- * SCHED_BATCH tasks are treated as perpetual CPU hogs:
- */
- if (policy == SCHED_BATCH)
- p->sleep_avg = 0;
- }
+
+ p->normal_prio = normal_prio(p);
+ /* we are holding p->pi_list already */
+ p->prio = rt_mutex_getprio(p);
+ /*
+ * SCHED_BATCH tasks are treated as perpetual CPU hogs:
+ */
+ if (policy == SCHED_BATCH)
+ p->sleep_avg = 0;
+
set_load_weight(p);
}
@@ -3942,6 +4036,11 @@ recheck:
if (retval)
return retval;
/*
+ * make sure no PI-waiters arrive (or leave) while we are
+ * changing the priority of the task:
+ */
+ spin_lock(&p->pi_lock);
+ /*
* To be able to change p->policy safely, the apropriate
* runqueue lock must be held.
*/
@@ -3950,6 +4049,7 @@ recheck:
if (unlikely(oldpolicy != -1 && oldpolicy != p->policy)) {
policy = oldpolicy = -1;
task_rq_unlock(rq, &flags);
+ spin_unlock(&p->pi_lock);
goto recheck;
}
array = p->array;
@@ -3971,6 +4071,8 @@ recheck:
resched_task(rq->curr);
}
task_rq_unlock(rq, &flags);
+ spin_unlock(&p->pi_lock);
+
return 0;
}
EXPORT_SYMBOL_GPL(sched_setscheduler);
@@ -4602,7 +4704,7 @@ void __devinit init_idle(task_t *idle, i
idle->timestamp = sched_clock();
idle->sleep_avg = 0;
idle->array = NULL;
- idle->prio = MAX_PRIO;
+ idle->prio = idle->normal_prio = MAX_PRIO;
idle->state = TASK_RUNNING;
idle->cpus_allowed = cpumask_of_cpu(cpu);
set_task_cpu(idle, cpu);
@@ -6602,6 +6704,7 @@ void normalize_rt_tasks(void)
if (!rt_task(p))
continue;
+ spin_lock(&p->pi_lock);
rq = task_rq_lock(p, &flags);
array = p->array;
@@ -6614,6 +6717,7 @@ void normalize_rt_tasks(void)
}
task_rq_unlock(rq, &flags);
+ spin_unlock(&p->pi_lock);
}
read_unlock_irq(&tasklist_lock);
}
_
Patches currently in -mm which might be from mingo@xxxxxxx are
git-acpi.patch
fix-drivers-mfd-ucb1x00-corec-irq-probing-bug.patch
git-infiniband.patch
git-netdev-all.patch
fix-for-serial-uart-lockup.patch
swapless-pm-add-r-w-migration-entries-fix.patch
i386-break-out-of-recursion-in-stackframe-walk.patch
x86-re-enable-generic-numa.patch
vdso-randomize-the-i386-vdso-by-moving-it-into-a-vma.patch
vdso-randomize-the-i386-vdso-by-moving-it-into-a-vma-tidy.patch
vdso-randomize-the-i386-vdso-by-moving-it-into-a-vma-arch_vma_name-fix.patch
work-around-ppc64-bootup-bug-by-making-mutex-debugging-save-restore-irqs.patch
kernel-kernel-cpuc-to-mutexes.patch
cond-resched-might-sleep-fix.patch
define-__raw_get_cpu_var-and-use-it.patch
ide-cd-end-of-media-error-fix.patch
spin-rwlock-init-cleanups.patch
time-clocksource-infrastructure.patch
sched-comment-bitmap-size-accounting.patch
sched-fix-interactive-ceiling-code.patch
sched-implement-smpnice.patch
sched-protect-calculation-of-max_pull-from-integer-wrap.patch
sched-store-weighted-load-on-up.patch
sched-add-discrete-weighted-cpu-load-function.patch
sched-prevent-high-load-weight-tasks-suppressing-balancing.patch
sched-improve-stability-of-smpnice-load-balancing.patch
sched-improve-smpnice-load-balancing-when-load-per-task.patch
smpnice-dont-consider-sched-groups-which-are-lightly-loaded-for-balancing.patch
smpnice-dont-consider-sched-groups-which-are-lightly-loaded-for-balancing-fix.patch
sched-modify-move_tasks-to-improve-load-balancing-outcomes.patch
sched-avoid-unnecessarily-moving-highest-priority-task-move_tasks.patch
sched-avoid-unnecessarily-moving-highest-priority-task-move_tasks-fix-2.patch
sched_domain-handle-kmalloc-failure.patch
sched_domain-handle-kmalloc-failure-fix.patch
sched_domain-dont-use-gfp_atomic.patch
sched_domain-use-kmalloc_node.patch
sched_domain-allocate-sched_group-structures-dynamically.patch
sched-add-above-background-load-function.patch
mm-implement-swap-prefetching-fix.patch
pi-futex-scheduler-support-for-pi.patch
pi-futex-rt-mutex-core.patch
pi-futex-rt-mutex-core-fix-timeout-race.patch
pi-futex-rt-mutex-docs.patch
pi-futex-rt-mutex-debug.patch
pi-futex-rt-mutex-tester.patch
pi-futex-rt-mutex-futex-api.patch
pi-futex-futex_lock_pi-futex_unlock_pi-support.patch
pi-futex-v2.patch
pi-futex-v3.patch
pi-futex-patchset-v4.patch
pi-futex-patchset-v4-update.patch
pi-futex-patchset-v4-fix.patch
rtmutex-remove-buggy-bug_on-in-pi-boosting-code.patch
futex-pi-enforce-waiter-bit-when-owner-died-is-detected.patch
rtmutex-debug-printk-correct-task-information.patch
futex-pi-make-use-of-restart_block-when-interrupted.patch
document-futex-pi-design.patch
futex_requeue-optimization.patch
reiser4.patch
reiser4-spin-rwlock-init-cleanups.patch
genirq-rename-desc-handler-to-desc-chip.patch
genirq-rename-desc-handler-to-desc-chip-power-fix.patch
genirq-rename-desc-handler-to-desc-chip-ia64-fix.patch
genirq-rename-desc-handler-to-desc-chip-ia64-fix-2.patch
genirq-sem2mutex-probe_sem-probing_active.patch
genirq-cleanup-merge-irq_affinity-into-irq_desc.patch
genirq-cleanup-remove-irq_descp.patch
genirq-cleanup-remove-fastcall.patch
genirq-cleanup-misc-code-cleanups.patch
genirq-cleanup-reduce-irq_desc_t-use-mark-it-obsolete.patch
genirq-cleanup-include-linux-irqh.patch
genirq-cleanup-merge-irq_dir-smp_affinity_entry-into-irq_desc.patch
genirq-cleanup-merge-pending_irq_cpumask-into-irq_desc.patch
genirq-cleanup-turn-arch_has_irq_per_cpu-into-config_irq_per_cpu.patch
genirq-debug-better-debug-printout-in-enable_irq.patch
genirq-add-retrigger-irq-op-to-consolidate-hw_irq_resend.patch
genirq-doc-comment-include-linux-irqh-structures.patch
genirq-doc-handle_irq_event-and-__do_irq-comments.patch
genirq-cleanup-no_irq_type-cleanups.patch
genirq-doc-add-design-documentation.patch
genirq-add-genirq-sw-irq-retrigger.patch
genirq-add-irq_noprobe-support.patch
genirq-add-irq_norequest-support.patch
genirq-add-irq_noautoen-support.patch
genirq-update-copyrights.patch
genirq-core.patch
genirq-add-irq-chip-support.patch
genirq-add-handle_bad_irq.patch
genirq-add-irq-wake-power-management-support.patch
genirq-add-sa_trigger-support.patch
genirq-cleanup-no_irq_type-no_irq_chip-rename.patch
genirq-convert-the-x86_64-architecture-to-irq-chips.patch
genirq-convert-the-i386-architecture-to-irq-chips.patch
genirq-convert-the-i386-architecture-to-irq-chips-fix-2.patch
genirq-more-verbose-debugging-on-unexpected-irq-vectors.patch
detect-atomic-counter-underflows.patch
debug-shared-irqs.patch
make-frame_pointer-default=y.patch
mutex-subsystem-synchro-test-module.patch
vdso-print-fatal-signals.patch
vdso-improve-print_fatal_signals-support-by-adding-memory-maps.patch
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