diff options
Diffstat (limited to 'target/linux/pistachio/patches-4.9/107-clockevents-Retry-programming-min-delta-up-to-10-tim.patch')
| -rw-r--r-- | target/linux/pistachio/patches-4.9/107-clockevents-Retry-programming-min-delta-up-to-10-tim.patch | 66 |
1 files changed, 0 insertions, 66 deletions
diff --git a/target/linux/pistachio/patches-4.9/107-clockevents-Retry-programming-min-delta-up-to-10-tim.patch b/target/linux/pistachio/patches-4.9/107-clockevents-Retry-programming-min-delta-up-to-10-tim.patch deleted file mode 100644 index 857823b783..0000000000 --- a/target/linux/pistachio/patches-4.9/107-clockevents-Retry-programming-min-delta-up-to-10-tim.patch +++ /dev/null @@ -1,66 +0,0 @@ -From b46f8c74afdd30cd52bfdcc2231470a0bab04416 Mon Sep 17 00:00:00 2001 -From: James Hogan <james.hogan@imgtec.com> -Date: Fri, 22 Apr 2016 18:22:45 +0100 -Subject: clockevents: Retry programming min delta up to 10 times - -Under virtualisation it is possible to get unexpected latency during a -clockevent device's set_next_event() callback which can make it return --ETIME even for a delta based on min_delta_ns. - -The clockevents_program_min_delta() implementation for -CONFIG_GENERIC_CLOCKEVENTS_MIN_ADJUST=n doesn't handle retries when this -happens, nor does clockevents_program_event() or its callers when force -is true (for example hrtimer_reprogram()). This can result in hangs -until the clock event device does a full period. - -It isn't appropriate to use MIN_ADJUST in this case as occasional -hypervisor induced high latency will cause min_delta_ns to quickly -increase to the maximum. -Instead, borrow the retry pattern from the MIN_ADJUST case, but without -making adjustments. We retry up to 10 times before giving up. - -(picked https://patchwork.kernel.org/patch/8909491/) - -Signed-off-by: James Hogan <james.hogan@imgtec.com> ---- - kernel/time/clockevents.c | 26 +++++++++++++++++++------- - 1 file changed, 19 insertions(+), 7 deletions(-) - ---- a/kernel/time/clockevents.c -+++ b/kernel/time/clockevents.c -@@ -281,16 +281,28 @@ static int clockevents_program_min_delta - { - unsigned long long clc; - int64_t delta; -+ int i; - -- delta = dev->min_delta_ns; -- dev->next_event = ktime_add_ns(ktime_get(), delta); -+ for (i = 0;;) { -+ delta = dev->min_delta_ns; -+ dev->next_event = ktime_add_ns(ktime_get(), delta); - -- if (clockevent_state_shutdown(dev)) -- return 0; -+ if (clockevent_state_shutdown(dev)) -+ return 0; - -- dev->retries++; -- clc = ((unsigned long long) delta * dev->mult) >> dev->shift; -- return dev->set_next_event((unsigned long) clc, dev); -+ dev->retries++; -+ clc = ((unsigned long long) delta * dev->mult) >> dev->shift; -+ if (dev->set_next_event((unsigned long) clc, dev) == 0) -+ return 0; -+ -+ if (++i > 9) { -+ /* -+ * We tried 10 times to program the device with the -+ * given min_delta_ns. Get out of here. -+ */ -+ return -ETIME; -+ } -+ } - } - - #endif /* CONFIG_GENERIC_CLOCKEVENTS_MIN_ADJUST */ |