2019-08-18 21:33:52 +00:00
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From bc6dc2730e93dec5ead183a44781b5c8bf47b3d7 Mon Sep 17 00:00:00 2001
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2018-08-27 14:32:32 +00:00
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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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2019-08-18 21:33:52 +00:00
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Subject: [PATCH 106/283] sched: Move task_struct cleanup to RCU
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Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.19/older/patches-4.19.59-rt24.tar.xz
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2018-08-27 14:32:32 +00:00
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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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2019-04-08 23:49:20 +00:00
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include/linux/sched.h | 3 +++
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include/linux/sched/task.h | 11 ++++++++++-
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kernel/fork.c | 15 ++++++++++++++-
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2018-08-27 14:32:32 +00:00
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3 files changed, 27 insertions(+), 2 deletions(-)
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2019-04-08 23:49:20 +00:00
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diff --git a/include/linux/sched.h b/include/linux/sched.h
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2019-04-30 12:45:19 +00:00
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index c2dfe6939773..a6f2f76b1162 100644
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2018-08-27 14:32:32 +00:00
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--- a/include/linux/sched.h
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+++ b/include/linux/sched.h
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2018-12-14 09:55:05 +00:00
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@@ -1186,6 +1186,9 @@ struct task_struct {
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2018-08-27 14:32:32 +00:00
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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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2019-04-08 23:49:20 +00:00
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diff --git a/include/linux/sched/task.h b/include/linux/sched/task.h
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index 108ede99e533..bb98c5b43f81 100644
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2018-08-27 14:32:32 +00:00
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--- a/include/linux/sched/task.h
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+++ b/include/linux/sched/task.h
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@@ -88,6 +88,15 @@ extern void sched_exec(void);
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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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2019-04-08 23:49:20 +00:00
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@@ -95,7 +104,7 @@ static inline void put_task_struct(struct task_struct *t)
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2018-08-27 14:32:32 +00:00
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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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-
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+#endif
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struct task_struct *task_rcu_dereference(struct task_struct **ptask);
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#ifdef CONFIG_ARCH_WANTS_DYNAMIC_TASK_STRUCT
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2019-04-08 23:49:20 +00:00
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diff --git a/kernel/fork.c b/kernel/fork.c
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2019-08-18 21:33:52 +00:00
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index 492bc898b09a..cba3cade3d5b 100644
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2018-08-27 14:32:32 +00:00
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--- a/kernel/fork.c
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+++ b/kernel/fork.c
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2019-04-08 23:49:20 +00:00
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@@ -671,7 +671,9 @@ static inline void put_signal_struct(struct signal_struct *sig)
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2018-08-27 14:32:32 +00:00
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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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2019-04-08 23:49:20 +00:00
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@@ -688,7 +690,18 @@ void __put_task_struct(struct task_struct *tsk)
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2018-08-27 14:32:32 +00:00
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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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2019-04-08 23:49:20 +00:00
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--
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2.20.1
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