diff options
Diffstat (limited to 'kernel/locking')
| -rw-r--r-- | kernel/locking/lockdep.c | 7 | ||||
| -rw-r--r-- | kernel/locking/lockdep_proc.c | 4 | ||||
| -rw-r--r-- | kernel/locking/osq_lock.c | 23 | ||||
| -rw-r--r-- | kernel/locking/qspinlock.c | 13 | ||||
| -rw-r--r-- | kernel/locking/rwsem.c | 4 |
5 files changed, 24 insertions, 27 deletions
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c index 32282e7112d3..32406ef0d6a2 100644 --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -482,7 +482,7 @@ static struct lock_trace *save_trace(void) struct lock_trace *trace, *t2; struct hlist_head *hash_head; u32 hash; - unsigned int max_entries; + int max_entries; BUILD_BUG_ON_NOT_POWER_OF_2(STACK_TRACE_HASH_SIZE); BUILD_BUG_ON(LOCK_TRACE_SIZE_IN_LONGS >= MAX_STACK_TRACE_ENTRIES); @@ -490,10 +490,8 @@ static struct lock_trace *save_trace(void) trace = (struct lock_trace *)(stack_trace + nr_stack_trace_entries); max_entries = MAX_STACK_TRACE_ENTRIES - nr_stack_trace_entries - LOCK_TRACE_SIZE_IN_LONGS; - trace->nr_entries = stack_trace_save(trace->entries, max_entries, 3); - if (nr_stack_trace_entries >= MAX_STACK_TRACE_ENTRIES - - LOCK_TRACE_SIZE_IN_LONGS - 1) { + if (max_entries <= 0) { if (!debug_locks_off_graph_unlock()) return NULL; @@ -502,6 +500,7 @@ static struct lock_trace *save_trace(void) return NULL; } + trace->nr_entries = stack_trace_save(trace->entries, max_entries, 3); hash = jhash(trace->entries, trace->nr_entries * sizeof(trace->entries[0]), 0); diff --git a/kernel/locking/lockdep_proc.c b/kernel/locking/lockdep_proc.c index dadb7b7fba37..9bb6d2497b04 100644 --- a/kernel/locking/lockdep_proc.c +++ b/kernel/locking/lockdep_proc.c @@ -286,9 +286,9 @@ static int lockdep_stats_show(struct seq_file *m, void *v) seq_printf(m, " stack-trace entries: %11lu [max: %lu]\n", nr_stack_trace_entries, MAX_STACK_TRACE_ENTRIES); #if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) - seq_printf(m, " number of stack traces: %llu\n", + seq_printf(m, " number of stack traces: %11llu\n", lockdep_stack_trace_count()); - seq_printf(m, " number of stack hash chains: %llu\n", + seq_printf(m, " number of stack hash chains: %11llu\n", lockdep_stack_hash_count()); #endif seq_printf(m, " combined max dependencies: %11u\n", diff --git a/kernel/locking/osq_lock.c b/kernel/locking/osq_lock.c index 6ef600aa0f47..1f7734949ac8 100644 --- a/kernel/locking/osq_lock.c +++ b/kernel/locking/osq_lock.c @@ -134,20 +134,17 @@ bool osq_lock(struct optimistic_spin_queue *lock) * cmpxchg in an attempt to undo our queueing. */ - while (!READ_ONCE(node->locked)) { - /* - * If we need to reschedule bail... so we can block. - * Use vcpu_is_preempted() to avoid waiting for a preempted - * lock holder: - */ - if (need_resched() || vcpu_is_preempted(node_cpu(node->prev))) - goto unqueue; - - cpu_relax(); - } - return true; + /* + * Wait to acquire the lock or cancelation. Note that need_resched() + * will come with an IPI, which will wake smp_cond_load_relaxed() if it + * is implemented with a monitor-wait. vcpu_is_preempted() relies on + * polling, be careful. + */ + if (smp_cond_load_relaxed(&node->locked, VAL || need_resched() || + vcpu_is_preempted(node_cpu(node->prev)))) + return true; -unqueue: + /* unqueue */ /* * Step - A -- stabilize @prev * diff --git a/kernel/locking/qspinlock.c b/kernel/locking/qspinlock.c index 2473f10c6956..b9515fcc9b29 100644 --- a/kernel/locking/qspinlock.c +++ b/kernel/locking/qspinlock.c @@ -31,14 +31,15 @@ /* * The basic principle of a queue-based spinlock can best be understood * by studying a classic queue-based spinlock implementation called the - * MCS lock. The paper below provides a good description for this kind - * of lock. + * MCS lock. A copy of the original MCS lock paper ("Algorithms for Scalable + * Synchronization on Shared-Memory Multiprocessors by Mellor-Crummey and + * Scott") is available at * - * http://www.cise.ufl.edu/tr/DOC/REP-1992-71.pdf + * https://bugzilla.kernel.org/show_bug.cgi?id=206115 * - * This queued spinlock implementation is based on the MCS lock, however to make - * it fit the 4 bytes we assume spinlock_t to be, and preserve its existing - * API, we must modify it somehow. + * This queued spinlock implementation is based on the MCS lock, however to + * make it fit the 4 bytes we assume spinlock_t to be, and preserve its + * existing API, we must modify it somehow. * * In particular; where the traditional MCS lock consists of a tail pointer * (8 bytes) and needs the next pointer (another 8 bytes) of its own node to diff --git a/kernel/locking/rwsem.c b/kernel/locking/rwsem.c index 44e68761f432..0d9b6be9ecc8 100644 --- a/kernel/locking/rwsem.c +++ b/kernel/locking/rwsem.c @@ -1226,8 +1226,8 @@ wait: * In this case, we attempt to acquire the lock again * without sleeping. */ - if ((wstate == WRITER_HANDOFF) && - (rwsem_spin_on_owner(sem, 0) == OWNER_NULL)) + if (wstate == WRITER_HANDOFF && + rwsem_spin_on_owner(sem, RWSEM_NONSPINNABLE) == OWNER_NULL) goto trylock_again; /* Block until there are no active lockers. */ |