Merge branch 'perf/urgent' into perf/core, to avoid conflicts

[firefly-linux-kernel-4.4.55.git] / kernel / hrtimer.c

diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
index 53d26829cd4d3dd00a6ce305f54d0a45fe7b7589..d10eba8089d164e376134bc54ab2d2f45818aab9 100644 (file)
--- a/kernel/hrtimer.c
+++ b/kernel/hrtimer.c
@@ -234,6 +234,11 @@ again:
                        goto again;
                }
                timer->base = new_base;
+       } else {
+               if (cpu != this_cpu && hrtimer_check_target(timer, new_base)) {
+                       cpu = this_cpu;
+                       goto again;
+               }
        }
        return new_base;
 }
@@ -569,6 +574,23 @@ hrtimer_force_reprogram(struct hrtimer_cpu_base *cpu_base, int skip_equal)
 
        cpu_base->expires_next.tv64 = expires_next.tv64;
 
+       /*
+        * If a hang was detected in the last timer interrupt then we
+        * leave the hang delay active in the hardware. We want the
+        * system to make progress. That also prevents the following
+        * scenario:
+        * T1 expires 50ms from now
+        * T2 expires 5s from now
+        *
+        * T1 is removed, so this code is called and would reprogram
+        * the hardware to 5s from now. Any hrtimer_start after that
+        * will not reprogram the hardware due to hang_detected being
+        * set. So we'd effectivly block all timers until the T2 event
+        * fires.
+        */
+       if (cpu_base->hang_detected)
+               return;
+
        if (cpu_base->expires_next.tv64 != KTIME_MAX)
                tick_program_event(cpu_base->expires_next, 1);
 }