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>

0 files changed, 0 insertions, 0 deletions