diff options
Diffstat (limited to 'kernel/locking/osq_lock.c')
| -rw-r--r-- | kernel/locking/osq_lock.c | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/kernel/locking/osq_lock.c b/kernel/locking/osq_lock.c index 8d7047ecef4e..0befa20ce96e 100644 --- a/kernel/locking/osq_lock.c +++ b/kernel/locking/osq_lock.c @@ -1,6 +1,7 @@ #include <linux/percpu.h> #include <linux/sched.h> #include <linux/osq_lock.h> +#include <linux/sched/rt.h> /* * An MCS like lock especially tailored for optimistic spinning for sleeping @@ -85,6 +86,7 @@ bool osq_lock(struct optimistic_spin_queue *lock) { struct optimistic_spin_node *node = this_cpu_ptr(&osq_node); struct optimistic_spin_node *prev, *next; + struct task_struct *task = current; int curr = encode_cpu(smp_processor_id()); int old; @@ -131,8 +133,13 @@ bool osq_lock(struct optimistic_spin_queue *lock) while (!READ_ONCE(node->locked)) { /* * If we need to reschedule bail... so we can block. + * If a task spins on owner on a CPU after acquiring + * osq_lock while a RT task spins on another CPU to + * acquire osq_lock, it will starve the owner from + * completing if owner is to be scheduled on the same CPU. + * It will be a live lock. */ - if (need_resched()) + if (need_resched() || rt_task(task)) goto unqueue; cpu_relax_lowlatency(); |