Messages in this thread Patch in this message | | | From | "Paul E. McKenney" <> | Subject | [PATCH tip/core/rcu 01/22] sched: Make non-production PREEMPT cond_resched() help Tasks RCU | Date | Sun, 22 Apr 2018 19:32:06 -0700 |
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In CONFIG_PREEMPT=y kernels, cond_resched() is a complete no-op, and thus cannot help advance Tasks-RCU grace periods. However, such grace periods are only an issue in non-production benchmarking runs of the Linux kernel. This commit therefore makes cond_resched() invoke rcu_note_voluntary_context_switch() for kernels implementing Tasks RCU even in CONFIG_PREEMPT=y kernels.
Reported-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> --- include/linux/sched.h | 6 ++++++ 1 file changed, 6 insertions(+)
diff --git a/include/linux/sched.h b/include/linux/sched.h index b3d697f3b573..fe8f7178a22d 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1617,6 +1617,12 @@ static inline int test_tsk_need_resched(struct task_struct *tsk) */ #ifndef CONFIG_PREEMPT extern int _cond_resched(void); +#elif defined(CONFIG_TRACEPOINT_BENCHMARK) +static inline int _cond_resched(void) +{ + rcu_note_voluntary_context_switch(current); + return 0; +} #else static inline int _cond_resched(void) { return 0; } #endif -- 2.5.2
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