From: Zhao Hongjiang <zhaohongjiang@xxxxxxxxxx>
When we run the test "taskset -c 1 stress -m 1 --vm-bytes 50M" and
"taskset -c 1 cyclictest -t 1 -p 80 -n -m -v" with rt closed 3.4.26-rt38 kernel,
the cyclictest's result is anomalous as follow:
0: 278: 1
0: 279: 2
0: 280: 17
0: 281: 1657
0: 282: 1680
0: 283: 4678
0: 284: 7026
0: 285: 6678
0: 286: 9677
0: 287: 12678
0: 288: 13090
0: 289: 14678
0: 290: 17677
0: 291: 20155
0: 292: 19678
0: 293: 22679
0: 294: 25676
0: 295: 26218
0: 296: 27679
0: 297: 30677
0: 298: 33283
0: 299: 32677
0: 300: 35676
and the result is increase continuously forever. We find that the patch
("hrtimer: fixup hrtimer callback changes for preempt-rt") has missed
hrtimer_peek_ahead_timers() in hrtimer_rt_run_pending() fuction in nort
code. We fix this and the test result isn't increase continuously as same
as the result with nort 3.4.26 kernel as follow:
0: 636: 8
0: 637: 7
0: 638: 8
0: 639: 9
0: 640: 7
0: 641: 9
0: 642: 8
0: 643: 8
0: 644: 8
0: 645: 32
0: 646: 8683
0: 647: 7760
0: 648: 6784
0: 649: 5797
0: 650: 4810
0: 651: 3823
0: 652: 2836
0: 653: 1849
0: 654: 862
0: 655: 7
0: 656: 7
0: 657: 7
0: 658: 6
0: 659: 8
0: 660: 7
Signed-off-by: Zhao Hongjiang <zhaohongjiang@xxxxxxxxxx>
Signed-off-by: Weng Meiling <wengmeiling.weng@xxxxxxxxxx>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
[PG: direct cherry pick of b236e408 from v3.6-rt]
Signed-off-by: Paul Gortmaker <paul.gortmaker@xxxxxxxxxxxxx>
diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
index c5f8b11..9d96d7a 100644
--- a/kernel/hrtimer.c
+++ b/kernel/hrtimer.c
@@ -1430,7 +1430,11 @@ static int hrtimer_rt_defer(struct hrtimer *timer)
#else
-static inline void hrtimer_rt_run_pending(void) { }
+static inline void hrtimer_rt_run_pending(void)
+{
+ hrtimer_peek_ahead_timers();
+}
+
static inline int hrtimer_rt_defer(struct hrtimer *timer) { return 0; }
#endif
--
1.8.1.2
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