diff --git a/kernel/time/timer.c b/kernel/time/timer.c
index 352b161113cd..d44dba1d4af0 100644
--- a/kernel/time/timer.c
+++ b/kernel/time/timer.c
@@ -196,6 +196,51 @@ EXPORT_SYMBOL(jiffies_64);
 # define BASE_DEF	0
 #endif
 
+/**
+ * struct timer_base - Per CPU timer base (number of base depends on config)
+ * @lock:		Lock protecting the timer_base
+ * @running_timer:	When expiring timers, the lock is dropped. To make
+ *			sure not to race agains deleting/modifying a
+ *			currently running timer, the pointer is set to the
+ *			timer, which expires at the moment. If no timer is
+ *			running, the pointer is NULL.
+ * @expiry_lock:	PREEMPT_RT only: Lock is taken in softirq around
+ *			timer expiry callback execution and when trying to
+ *			delete a running timer and it wasn't successful in
+ *			the first glance. It prevents priority inversion
+ *			when callback was preempted on a remote CPU and a
+ *			caller tries to delete the running timer. It also
+ *			prevents a life lock, when the task which tries to
+ *			delete a timer preempted the softirq thread which
+ *			is running the timer callback function.
+ * @timer_waiters:	PREEMPT_RT only: Tells, if there is a waiter
+ *			waiting for the end of the timer callback function
+ *			execution.
+ * @clk:		clock of the timer base; is updated before enqueue
+ *			of a timer; during expiry, it is 1 offset ahead of
+ *			jiffies to avoid endless requeuing to current
+ *			jiffies
+ * @next_expiry:	expiry value of the first timer; it is updated when
+ *			finding the next timer and during enqueue; the
+ *			value is not valid, when next_expiry_recalc is set
+ * @cpu:		Number of CPU the timer base belongs to
+ * @next_expiry_recalc: States, whether a recalculation of next_expiry is
+ *			required. Value is set true, when a timer was
+ *			deleted.
+ * @is_idle:		Is set, when timer_base is idle. It is triggered by NOHZ
+ *			code. This state is only used in standard
+ *			base. Deferrable timers, which are enqueued remotely
+ *			never wake up an idle CPU. So no matter of supporting it
+ *			for this base.
+ * @timers_pending:	Is set, when a timer is pending in the base. It is only
+ *			reliable when next_expiry_recalc is not set.
+ * @pending_map:	bitmap of the timer wheel; each bit reflects a
+ *			bucket of the wheel. When a bit is set, at least a
+ *			single timer is enqueued in the related bucket.
+ * @vectors:		Array of lists; Each array member reflects a bucket
+ *			of the timer wheel. The list contains all timers
+ *			which are enqueued into a specific bucket.
+ */
 struct timer_base {
 	raw_spinlock_t		lock;
 	struct timer_list	*running_timer;