90 lines
3.0 KiB
Diff
90 lines
3.0 KiB
Diff
From 5b806c00aacae2ae74726e6adec729bb2b328bcb Mon Sep 17 00:00:00 2001
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From: Thomas Gleixner <tglx@linutronix.de>
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Date: Sat, 25 Jun 2011 09:21:04 +0200
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Subject: [PATCH 145/290] sched-rt-mutex-wakeup.patch
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Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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---
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include/linux/sched.h | 3 +++
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kernel/sched.c | 31 ++++++++++++++++++++++++++++++-
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2 files changed, 33 insertions(+), 1 deletion(-)
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diff --git a/include/linux/sched.h b/include/linux/sched.h
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index 3f36640..57d5b54 100644
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--- a/include/linux/sched.h
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+++ b/include/linux/sched.h
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@@ -1073,6 +1073,7 @@ struct sched_domain;
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#define WF_SYNC 0x01 /* waker goes to sleep after wakup */
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#define WF_FORK 0x02 /* child wakeup after fork */
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#define WF_MIGRATED 0x04 /* internal use, task got migrated */
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+#define WF_LOCK_SLEEPER 0x08 /* wakeup spinlock "sleeper" */
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#define ENQUEUE_WAKEUP 1
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#define ENQUEUE_HEAD 2
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@@ -1222,6 +1223,7 @@ enum perf_event_task_context {
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struct task_struct {
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volatile long state; /* -1 unrunnable, 0 runnable, >0 stopped */
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+ volatile long saved_state; /* saved state for "spinlock sleepers" */
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void *stack;
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atomic_t usage;
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unsigned int flags; /* per process flags, defined below */
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@@ -2190,6 +2192,7 @@ extern void xtime_update(unsigned long ticks);
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extern int wake_up_state(struct task_struct *tsk, unsigned int state);
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extern int wake_up_process(struct task_struct *tsk);
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+extern int wake_up_lock_sleeper(struct task_struct * tsk);
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extern void wake_up_new_task(struct task_struct *tsk);
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#ifdef CONFIG_SMP
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extern void kick_process(struct task_struct *tsk);
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diff --git a/kernel/sched.c b/kernel/sched.c
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index 8af4f7f..d3e327d 100644
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--- a/kernel/sched.c
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+++ b/kernel/sched.c
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@@ -2823,8 +2823,25 @@ try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags)
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smp_wmb();
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raw_spin_lock_irqsave(&p->pi_lock, flags);
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- if (!(p->state & state))
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+ if (!(p->state & state)) {
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+ /*
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+ * The task might be running due to a spinlock sleeper
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+ * wakeup. Check the saved state and set it to running
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+ * if the wakeup condition is true.
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+ */
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+ if (!(wake_flags & WF_LOCK_SLEEPER)) {
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+ if (p->saved_state & state)
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+ p->saved_state = TASK_RUNNING;
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+ }
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goto out;
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+ }
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+
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+ /*
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+ * If this is a regular wakeup, then we can unconditionally
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+ * clear the saved state of a "lock sleeper".
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+ */
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+ if (!(wake_flags & WF_LOCK_SLEEPER))
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+ p->saved_state = TASK_RUNNING;
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success = 1; /* we're going to change ->state */
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cpu = task_cpu(p);
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@@ -2896,6 +2913,18 @@ int wake_up_process(struct task_struct *p)
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}
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EXPORT_SYMBOL(wake_up_process);
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+/**
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+ * wake_up_lock_sleeper - Wake up a specific process blocked on a "sleeping lock"
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+ * @p: The process to be woken up.
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+ *
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+ * Same as wake_up_process() above, but wake_flags=WF_LOCK_SLEEPER to indicate
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+ * the nature of the wakeup.
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+ */
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+int wake_up_lock_sleeper(struct task_struct *p)
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+{
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+ return try_to_wake_up(p, TASK_ALL, WF_LOCK_SLEEPER);
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+}
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+
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int wake_up_state(struct task_struct *p, unsigned int state)
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{
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return try_to_wake_up(p, state, 0);
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