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authorPaul E. McKenney <paulmck@kernel.org>2020-02-04 15:00:56 -0800
committerPaul E. McKenney <paulmck@kernel.org>2020-02-20 16:03:31 -0800
commit50d4b62970e21e9573daf0e3c1138b4d1ebcca47 (patch)
tree9b9a542b7b632ceb3bdef16513e5717de0438e9d /kernel/rcu
parent12af660321263d7744d5d06b765c7b03fade3858 (diff)
downloadlinux-50d4b62970e21e9573daf0e3c1138b4d1ebcca47.tar.bz2
rcutorture: Make rcu_torture_barrier_cbs() post from corresponding CPU
Currently, rcu_torture_barrier_cbs() posts callbacks from whatever CPU it is running on, which means that all these kthreads might well be posting from the same CPU, which would drastically reduce the effectiveness of this test. This commit therefore uses IPIs to make the callbacks be posted from the corresponding CPU (given by local variable myid). If the IPI fails (which can happen if the target CPU is offline or does not exist at all), the callback is posted on whatever CPU is currently running. Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Diffstat (limited to 'kernel/rcu')
-rw-r--r--kernel/rcu/rcutorture.c16
1 files changed, 13 insertions, 3 deletions
diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
index 7e01e9a87352..f82515cded34 100644
--- a/kernel/rcu/rcutorture.c
+++ b/kernel/rcu/rcutorture.c
@@ -2053,6 +2053,14 @@ static void rcu_torture_barrier_cbf(struct rcu_head *rcu)
atomic_inc(&barrier_cbs_invoked);
}
+/* IPI handler to get callback posted on desired CPU, if online. */
+static void rcu_torture_barrier1cb(void *rcu_void)
+{
+ struct rcu_head *rhp = rcu_void;
+
+ cur_ops->call(rhp, rcu_torture_barrier_cbf);
+}
+
/* kthread function to register callbacks used to test RCU barriers. */
static int rcu_torture_barrier_cbs(void *arg)
{
@@ -2076,9 +2084,11 @@ static int rcu_torture_barrier_cbs(void *arg)
* The above smp_load_acquire() ensures barrier_phase load
* is ordered before the following ->call().
*/
- local_irq_disable(); /* Just to test no-irq call_rcu(). */
- cur_ops->call(&rcu, rcu_torture_barrier_cbf);
- local_irq_enable();
+ if (smp_call_function_single(myid, rcu_torture_barrier1cb,
+ &rcu, 1)) {
+ // IPI failed, so use direct call from current CPU.
+ cur_ops->call(&rcu, rcu_torture_barrier_cbf);
+ }
if (atomic_dec_and_test(&barrier_cbs_count))
wake_up(&barrier_wq);
} while (!torture_must_stop());