83 lines
2.4 KiB
Diff
83 lines
2.4 KiB
Diff
Subject: sched: Move task_struct cleanup to RCU
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From: Thomas Gleixner <tglx@linutronix.de>
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Date: Tue, 31 May 2011 16:59:16 +0200
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Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.9/older/patches-4.9-rt1.tar.xz
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__put_task_struct() does quite some expensive work. We don't want to
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burden random tasks with that.
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Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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---
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include/linux/sched.h | 13 +++++++++++++
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kernel/fork.c | 15 ++++++++++++++-
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2 files changed, 27 insertions(+), 1 deletion(-)
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--- a/include/linux/sched.h
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+++ b/include/linux/sched.h
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@@ -1961,6 +1961,9 @@ struct task_struct {
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unsigned int sequential_io;
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unsigned int sequential_io_avg;
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#endif
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+#ifdef CONFIG_PREEMPT_RT_BASE
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+ struct rcu_head put_rcu;
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+#endif
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#ifdef CONFIG_DEBUG_ATOMIC_SLEEP
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unsigned long task_state_change;
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#endif
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@@ -2218,6 +2221,15 @@ extern struct pid *cad_pid;
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extern void free_task(struct task_struct *tsk);
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#define get_task_struct(tsk) do { atomic_inc(&(tsk)->usage); } while(0)
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+#ifdef CONFIG_PREEMPT_RT_BASE
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+extern void __put_task_struct_cb(struct rcu_head *rhp);
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+
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+static inline void put_task_struct(struct task_struct *t)
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+{
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+ if (atomic_dec_and_test(&t->usage))
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+ call_rcu(&t->put_rcu, __put_task_struct_cb);
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+}
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+#else
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extern void __put_task_struct(struct task_struct *t);
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static inline void put_task_struct(struct task_struct *t)
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@@ -2225,6 +2237,7 @@ static inline void put_task_struct(struc
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if (atomic_dec_and_test(&t->usage))
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__put_task_struct(t);
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}
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+#endif
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struct task_struct *task_rcu_dereference(struct task_struct **ptask);
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struct task_struct *try_get_task_struct(struct task_struct **ptask);
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--- a/kernel/fork.c
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+++ b/kernel/fork.c
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@@ -376,7 +376,9 @@ static inline void put_signal_struct(str
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if (atomic_dec_and_test(&sig->sigcnt))
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free_signal_struct(sig);
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}
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-
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+#ifdef CONFIG_PREEMPT_RT_BASE
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+static
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+#endif
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void __put_task_struct(struct task_struct *tsk)
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{
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WARN_ON(!tsk->exit_state);
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@@ -393,7 +395,18 @@ void __put_task_struct(struct task_struc
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if (!profile_handoff_task(tsk))
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free_task(tsk);
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}
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+#ifndef CONFIG_PREEMPT_RT_BASE
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EXPORT_SYMBOL_GPL(__put_task_struct);
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+#else
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+void __put_task_struct_cb(struct rcu_head *rhp)
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+{
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+ struct task_struct *tsk = container_of(rhp, struct task_struct, put_rcu);
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+
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+ __put_task_struct(tsk);
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+
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+}
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+EXPORT_SYMBOL_GPL(__put_task_struct_cb);
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+#endif
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void __init __weak arch_task_cache_init(void) { }
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