diff options
| -rw-r--r-- | kernel/bpf/rqspinlock.c | 18 |
1 files changed, 8 insertions, 10 deletions
diff --git a/kernel/bpf/rqspinlock.c b/kernel/bpf/rqspinlock.c index e602cbbbd029..e35b06fcf9ee 100644 --- a/kernel/bpf/rqspinlock.c +++ b/kernel/bpf/rqspinlock.c @@ -450,19 +450,17 @@ queue: * not be nested NMIs taking spinlocks. That may not be true in * some architectures even though the chance of needing more than * 4 nodes will still be extremely unlikely. When that happens, - * we fall back to spinning on the lock directly without using - * any MCS node. This is not the most elegant solution, but is - * simple enough. + * we fall back to attempting a trylock operation without using + * any MCS node. Unlike qspinlock which cannot fail, we have the + * option of failing the slow path, and under contention, such a + * trylock spinning will likely be treated unfairly due to lack of + * queueing, hence do not spin. */ if (unlikely(idx >= _Q_MAX_NODES || (in_nmi() && idx > 0))) { lockevent_inc(lock_no_node); - RES_RESET_TIMEOUT(ts, RES_DEF_TIMEOUT); - while (!queued_spin_trylock(lock)) { - if (RES_CHECK_TIMEOUT(ts, ret, ~0u)) { - lockevent_inc(rqspinlock_lock_timeout); - goto err_release_node; - } - cpu_relax(); + if (!queued_spin_trylock(lock)) { + ret = -EDEADLK; + goto err_release_node; } goto release; } |