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authorPaul E. McKenney <paulmck@kernel.org>2022-03-04 10:41:44 -0800
committerPaul E. McKenney <paulmck@kernel.org>2022-04-11 17:06:42 -0700
commit5d90070816534882b9158f14154b7e2cdef1194a (patch)
treeff57ad59d100eaba92b197926d88ca504378df30 /include/linux/rcupdate.h
parent88db792bbe9b140680c74e9f2f801ac00f54e05e (diff)
downloadlinux-5d90070816534882b9158f14154b7e2cdef1194a.tar.bz2
rcu-tasks: Make Tasks RCU account for userspace execution
The main Tasks RCU quiescent state is voluntary context switch. However, userspace execution is also a valid quiescent state, and is a valuable one for userspace applications that spin repeatedly executing light-weight non-sleeping system calls. Currently, such an application can delay a Tasks RCU grace period for many tens of seconds. This commit therefore enlists the aid of the scheduler-clock interrupt to provide a Tasks RCU quiescent state when it interrupted a task executing in userspace. [ paulmck: Apply feedback from kernel test robot. ] Cc: Martin KaFai Lau <kafai@fb.com> Cc: Neil Spring <ntspring@fb.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Diffstat (limited to 'include/linux/rcupdate.h')
-rw-r--r--include/linux/rcupdate.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index e7c39c200e2b..1a32036c918c 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -196,6 +196,7 @@ void synchronize_rcu_tasks_rude(void);
void exit_tasks_rcu_start(void);
void exit_tasks_rcu_finish(void);
#else /* #ifdef CONFIG_TASKS_RCU_GENERIC */
+#define rcu_tasks_classic_qs(t, preempt) do { } while (0)
#define rcu_tasks_qs(t, preempt) do { } while (0)
#define rcu_note_voluntary_context_switch(t) do { } while (0)
#define call_rcu_tasks call_rcu