diff options
| author | Paul E. McKenney <paulmck@linux.ibm.com> | 2019-04-19 07:38:27 -0700 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.ibm.com> | 2019-05-28 09:06:09 -0700 |
| commit | c682db558e6eec10a711b0a6bcb8c35fd15f6a39 (patch) | |
| tree | 2ef1e00e69c82e2181a85b6ef32af5741cc2a7f2 /kernel/rcu/rcu.h | |
| parent | 3432d765c59ba026de49bd4f1f0c2adeff0e7a16 (diff) | |
| download | linux-c682db558e6eec10a711b0a6bcb8c35fd15f6a39.tar.bz2 | |
rcutorture: Add trivial RCU implementation
I have been showing off a trivial RCU implementation for non-preemptive
environments for some time now:
#define rcu_read_lock()
#define rcu_read_unlock()
#define rcu_dereference(p) READ_ONCE(p)
#define rcu_assign_pointer(p, v) smp_store_release(&(p), (v))
void synchronize_rcu(void)
{
int cpu;
for_each_online_cpu(cpu)
sched_setaffinity(current->pid, cpumask_of(cpu));
}
Trivial or not, as the old saying goes, "if it ain't tested, it don't
work!". This commit therefore adds a "trivial" flavor to rcutorture
and a corresponding TRIVIAL test scenario. This variant does not handle
CPU hotplug, which is unconditionally enabled on x86 for post-v5.1-rc3
kernels, which is why the TRIVIAL.boot says "rcutorture.onoff_interval=0".
This commit actually does handle CONFIG_PREEMPT=y kernels, but only
because it turns back the Linux-kernel clock in order to provide these
alternative definitions (or the moral equivalent thereof):
#define rcu_read_lock() preempt_disable()
#define rcu_read_unlock() preempt_enable()
In CONFIG_PREEMPT=n kernels without debugging, these are equivalent to
empty macros give or take a compiler barrier. However, the have been
successfully tested with actual empty macros as well.
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
[ paulmck: Fix symbol issue reported by kbuild test robot <lkp@intel.com>. ]
[ paulmck: Work around sched_setaffinity() issue noted by Andrea Parri. ]
[ paulmck: Add rcutorture.shuffle_interval=0 to TRIVIAL.boot to fix
interaction with shuffler task noted by Peter Zijlstra. ]
Tested-by: Andrea Parri <andrea.parri@amarulasolutions.com>
Diffstat (limited to 'kernel/rcu/rcu.h')
| -rw-r--r-- | kernel/rcu/rcu.h | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/kernel/rcu/rcu.h b/kernel/rcu/rcu.h index 390aab20115e..5290b01de534 100644 --- a/kernel/rcu/rcu.h +++ b/kernel/rcu/rcu.h @@ -446,6 +446,7 @@ void rcu_request_urgent_qs_task(struct task_struct *t); enum rcutorture_type { RCU_FLAVOR, RCU_TASKS_FLAVOR, + RCU_TRIVIAL_FLAVOR, SRCU_FLAVOR, INVALID_RCU_FLAVOR }; @@ -479,6 +480,10 @@ void do_trace_rcu_torture_read(const char *rcutorturename, #endif #endif +#if IS_ENABLED(CONFIG_RCU_TORTURE_TEST) || IS_MODULE(CONFIG_RCU_TORTURE_TEST) +long rcutorture_sched_setaffinity(pid_t pid, const struct cpumask *in_mask); +#endif + #ifdef CONFIG_TINY_SRCU static inline void srcutorture_get_gp_data(enum rcutorture_type test_type, |