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| author | Peter Zijlstra <peterz@infradead.org> | 2013-08-14 14:55:46 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2013-09-25 14:07:52 +0200 |
| commit | 01028747559ac6c6f642a7bbd2875cc4f66b2feb (patch) | |
| tree | 3672a4ca3409cae40d5c7338ad9bfa590045dcbc | |
| parent | sched, arch: Create asm/preempt.h (diff) | |
| download | linux-01028747559ac6c6f642a7bbd2875cc4f66b2feb.tar.xz linux-01028747559ac6c6f642a7bbd2875cc4f66b2feb.zip | |
sched: Create more preempt_count accessors
We need a few special preempt_count accessors:
- task_preempt_count() for when we're interested in the preemption
count of another (non-running) task.
- init_task_preempt_count() for properly initializing the preemption
count.
- init_idle_preempt_count() a special case of the above for the idle
threads.
With these no generic code ever touches thread_info::preempt_count
anymore and architectures could choose to remove it.
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/n/tip-jf5swrio8l78j37d06fzmo4r@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
| -rw-r--r-- | include/asm-generic/preempt.h | 14 | ||||
| -rw-r--r-- | include/trace/events/sched.h | 2 | ||||
| -rw-r--r-- | kernel/sched/core.c | 7 |
3 files changed, 18 insertions, 5 deletions
diff --git a/include/asm-generic/preempt.h b/include/asm-generic/preempt.h index a1fc6590a743..8100b1ec1715 100644 --- a/include/asm-generic/preempt.h +++ b/include/asm-generic/preempt.h @@ -28,6 +28,20 @@ static __always_inline void preempt_count_set(int pc) } /* + * must be macros to avoid header recursion hell + */ +#define task_preempt_count(p) \ + (task_thread_info(p)->preempt_count & ~PREEMPT_NEED_RESCHED) + +#define init_task_preempt_count(p) do { \ + task_thread_info(p)->preempt_count = PREEMPT_DISABLED; \ +} while (0) + +#define init_idle_preempt_count(p, cpu) do { \ + task_thread_info(p)->preempt_count = PREEMPT_ENABLED; \ +} while (0) + +/* * We fold the NEED_RESCHED bit into the preempt count such that * preempt_enable() can decrement and test for needing to reschedule with a * single instruction. diff --git a/include/trace/events/sched.h b/include/trace/events/sched.h index 2e7d9947a10d..613381bcde40 100644 --- a/include/trace/events/sched.h +++ b/include/trace/events/sched.h @@ -100,7 +100,7 @@ static inline long __trace_sched_switch_state(struct task_struct *p) /* * For all intents and purposes a preempted task is a running task. */ - if (task_thread_info(p)->preempt_count & PREEMPT_ACTIVE) + if (task_preempt_count(p) & PREEMPT_ACTIVE) state = TASK_RUNNING | TASK_STATE_MAX; #endif diff --git a/kernel/sched/core.c b/kernel/sched/core.c index ee61f5affd20..0ba4e4192390 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -983,7 +983,7 @@ void set_task_cpu(struct task_struct *p, unsigned int new_cpu) * ttwu() will sort out the placement. */ WARN_ON_ONCE(p->state != TASK_RUNNING && p->state != TASK_WAKING && - !(task_thread_info(p)->preempt_count & PREEMPT_ACTIVE)); + !(task_preempt_count(p) & PREEMPT_ACTIVE)); #ifdef CONFIG_LOCKDEP /* @@ -1723,8 +1723,7 @@ void sched_fork(struct task_struct *p) p->on_cpu = 0; #endif #ifdef CONFIG_PREEMPT_COUNT - /* Want to start with kernel preemption disabled. */ - task_thread_info(p)->preempt_count = PREEMPT_DISABLED; + init_task_preempt_count(p); #endif #ifdef CONFIG_SMP plist_node_init(&p->pushable_tasks, MAX_PRIO); @@ -4217,7 +4216,7 @@ void init_idle(struct task_struct *idle, int cpu) raw_spin_unlock_irqrestore(&rq->lock, flags); /* Set the preempt count _outside_ the spinlocks! */ - task_thread_info(idle)->preempt_count = PREEMPT_ENABLED; + init_idle_preempt_count(idle, cpu); /* * The idle tasks have their own, simple scheduling class: |