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| author | Paul E. McKenney <paul.mckenney@linaro.org> | 2012-03-27 16:02:08 -0700 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2012-05-02 14:43:23 -0700 |
| commit | 616c310e83b872024271c915c1b9ab505b9efad9 (patch) | |
| tree | 1339bc7b3bef920b4641a5af2f182e9dfa2a6632 /include/linux/sched.h | |
| parent | 66f75a5d028beaf67c931435fdc3e7823125730c (diff) | |
| download | blackbird-op-linux-616c310e83b872024271c915c1b9ab505b9efad9.tar.gz blackbird-op-linux-616c310e83b872024271c915c1b9ab505b9efad9.zip | |
rcu: Move PREEMPT_RCU preemption to switch_to() invocation
Currently, PREEMPT_RCU readers are enqueued upon entry to the scheduler.
This is inefficient because enqueuing is required only if there is a
context switch, and entry to the scheduler does not guarantee a context
switch.
The commit therefore moves the enqueuing to immediately precede the
call to switch_to() from the scheduler.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/sched.h')
| -rw-r--r-- | include/linux/sched.h | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/include/linux/sched.h b/include/linux/sched.h index 81a173c0897d..8f3fd945070f 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1905,12 +1905,22 @@ static inline void rcu_copy_process(struct task_struct *p) INIT_LIST_HEAD(&p->rcu_node_entry); } +static inline void rcu_switch_from(struct task_struct *prev) +{ + if (prev->rcu_read_lock_nesting != 0) + rcu_preempt_note_context_switch(); +} + #else static inline void rcu_copy_process(struct task_struct *p) { } +static inline void rcu_switch_from(struct task_struct *prev) +{ +} + #endif #ifdef CONFIG_SMP |
