Re: [PATCH RFC clocksource 2/5] clocksource: Retry clock read if long delays detected

Rik van Riel
2021-01-06T16:29:13Z

On Tue, 2021-01-05 at 16:41 -0800, paulmck@kernel.org wrote:
>
> @@ -203,7 +204,6 @@ static void
> clocksource_watchdog_inject_delay(void)
> injectfail = inject_delay_run;
> if (!(++injectfail / inject_delay_run % inject_delay_freq)) {
> printk("%s(): Injecting delay.\n", __func__);
> - injectfail = 0;
> for (i = 0; i < 2 * WATCHDOG_THRESHOLD / NSEC_PER_MSEC;
> i++)
> udelay(1000);

Wait, patch 1 just added that line?

Should patch 1 not add it and this
patch go without
this removal? :)

+ wdagain_nsec = clocksource_cyc2ns(delta, watchdog-
>mult, watchdog->shift);
+ if (wdagain_nsec < 0 || wdagain_nsec >
WATCHDOG_MAX_SKEW) {
+ wderr_nsec = wdagain_nsec;
+ if (nretries++ < max_read_retries)
+ goto retry;
+ }

Given that clocksource_cyc2ns uses unsigned multiplication
followed by a right shift, do we need to test for <0?