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| author |   Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2017-04-11 15:50:41 -0700 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2017-04-21 05:59:27 -0700 |
| commit | bcbfdd01dce5556a952fae84ef16fd0f12525e7b (patch) | |
| tree | d674b23e7a573c6e5234acb5e914fc60e581594a /include/linux/rcutiny.h | |
| parent | srcu: Expedite srcu_schedule_cbs_snp() callback invocation (diff) | |
| download | linux-dev-bcbfdd01dce5556a952fae84ef16fd0f12525e7b.tar.xz linux-dev-bcbfdd01dce5556a952fae84ef16fd0f12525e7b.zip | |
rcu: Make non-preemptive schedule be Tasks RCU quiescent state
Currently, a call to schedule() acts as a Tasks RCU quiescent state
only if a context switch actually takes place. However, just the
call to schedule() guarantees that the calling task has moved off of
whatever tracing trampoline that it might have been one previously.
This commit therefore plumbs schedule()'s "preempt" parameter into
rcu_note_context_switch(), which then records the Tasks RCU quiescent
state, but only if this call to schedule() was -not- due to a preemption.
To avoid adding overhead to the common-case context-switch path,
this commit hides the rcu_note_context_switch() check under an existing
non-common-case check.
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Diffstat (limited to 'include/linux/rcutiny.h')
| -rw-r--r-- | include/linux/rcutiny.h | 13 |
1 files changed, 9 insertions, 4 deletions
diff --git a/include/linux/rcutiny.h b/include/linux/rcutiny.h index 5219be250f00..74d9c3a1feee 100644 --- a/include/linux/rcutiny.h +++ b/include/linux/rcutiny.h @@ -92,10 +92,11 @@ static inline void kfree_call_rcu(struct rcu_head *head, call_rcu(head, func); } -static inline void rcu_note_context_switch(void) -{ - rcu_sched_qs(); -} +#define rcu_note_context_switch(preempt) \ + do { \ + rcu_sched_qs(); \ + rcu_note_voluntary_context_switch_lite(current); \ + } while (0) /* * Take advantage of the fact that there is only one CPU, which @@ -242,6 +243,10 @@ static inline bool rcu_is_watching(void) #endif /* #else defined(CONFIG_DEBUG_LOCK_ALLOC) || defined(CONFIG_RCU_TRACE) */ +static inline void rcu_request_urgent_qs_task(struct task_struct *t) +{ +} + static inline void rcu_all_qs(void) { barrier(); /* Avoid RCU read-side critical sections leaking across. */ |