diff --git a/fs/proc/base.c b/fs/proc/base.c
index a45d4d640f01..56b1c4f1e8c0 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -95,6 +95,7 @@
 #include <linux/flex_array.h>
 #include <linux/posix-timers.h>
 #include <trace/events/oom.h>
+#include <linux/swait.h>
 #include "internal.h"
 #include "fd.h"
 
diff --git a/kernel/softirq.c b/kernel/softirq.c
index 73dae64bfc9c..9bad7a16dc61 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -947,10 +947,12 @@ static void __tasklet_schedule_common(struct tasklet_struct *t,
 	 * is locked before adding it to the list.
 	 */
 	if (test_bit(TASKLET_STATE_SCHED, &t->state)) {
+#if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT_RT_FULL)
 		if (test_and_set_bit(TASKLET_STATE_CHAINED, &t->state)) {
 			tasklet_unlock(t);
 			return;
 		}
+#endif
 		t->next = NULL;
 		*head->tail = t;
 		head->tail = &(t->next);
@@ -1044,7 +1046,11 @@ static void tasklet_action_common(struct softirq_action *a,
 again:
 		t->func(t->data);
 
+#if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT_RT_FULL)
 		while (cmpxchg(&t->state, TASKLET_STATEF_RC, 0) != TASKLET_STATEF_RC) {
+#else
+		while (!tasklet_tryunlock(t)) {
+#endif
 			/*
 			 * If it got disabled meanwhile, bail out:
 			 */
diff --git a/localversion-rt b/localversion-rt
index 3165a8781ff5..51b05e9abe6f 100644
--- a/localversion-rt
+++ b/localversion-rt
@@ -1 +1 @@
--rt54
+-rt55
diff --git a/mm/slub.c b/mm/slub.c
index d243c6ef7fc9..a9473bbb1338 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -2341,9 +2341,6 @@ static void flush_all(struct kmem_cache *s)
 	for_each_online_cpu(cpu) {
 		struct slub_free_list *f;
 
-		if (!has_cpu_slab(cpu, s))
-			continue;
-
 		f = &per_cpu(slub_free_list, cpu);
 		raw_spin_lock_irq(&f->lock);
 		list_splice_init(&f->list, &tofree);