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sched/walt: Drop arch-specific timer access

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On at least one platform, occasionally the timer providing the wallclock
was able to be reset/go backwards for at least some time after wakeup.

Accept that this might happen and warn the first time, but otherwise just
carry on.

Change-Id: Id3164477ba79049561af7f0889cbeebc199ead4e
Signed-off-by: Chris Redpath <chris.redpath@arm.com>
This commit is contained in:
Chris Redpath
2016-09-20 17:00:47 +01:00
committed by Dmitry Shmidt
parent b7c491d2c4
commit cf43809d7a
1 changed files with 2 additions and 5 deletions
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7
kernel/sched/walt.c
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@@ -22,7 +22,6 @@
#include <linux/syscore_ops.h>
#include <linux/cpufreq.h>
#include <trace/events/sched.h>
#include <clocksource/arm_arch_timer.h>
#include "sched.h"
#include "walt.h"
@@ -188,10 +187,8 @@ update_window_start(struct rq *rq, u64 wallclock)
delta = wallclock - rq->window_start;
/* If the MPM global timer is cleared, set delta as 0 to avoid kernel BUG happening */
if (delta < 0) {
if (arch_timer_read_counter() == 0)
delta = 0;
else
BUG_ON(1);
delta = 0;
WARN_ONCE(1, "WALT wallclock appears to have gone backwards or reset\n");
}
if (delta < walt_ravg_window)