> >>>>>> -#define TIMEOUT (20 * HZ) > >>>>>> +unsigned int __read_mostly sys_freeze_process_timeout_msecs = > >> 20000; > >>>>> > >>>>> 20000 does not mean 20 seconds since we can select HZ other than > 1000. > >>>>> So (20 * HZ) is better than 20000. > >>>>> > >>>> [Li, Fei] > >>>> Are you sure about this, (20*HZ) better than 20000, or you mean 20 * > >> MSEC_PER_SEC? > >>> Yasuaki mean HZ value will not always be 1000.The value of HZ differs for > >> each > >>> supported architecture. In fact, on some supported architectures, > >>> it even differs between machine types. > >>> When writing kernel code, never assume that HZ has any given value. > >>> Right now you are assuming that the delay will be always 20 seconds > because > >> of > >>> your assumption of HZ. > >> > >> That's correct, the initial value should be 20 * HZ (i.e. as before). > > [Li, Fei] > > Yes, you are right, and IMHO it's already as this in the patch, > > as 20 * HZ == msecs_to_jiffies(20000), with the current definition > MSEC_PER_SEC > > of 1000L. I'll update the default value as 20 * MSEC_PER_SEC in patch V4. > > 20 * MSEC_PER_SEC is not 20 seconds. In Linux, 1 * HZ is 1 seconds. Sure.
> Thus, > - If HZ is defined as 1000, 1000 is 1 seconds. > - If HZ is defined as 250, 250 is 1 seconds. > > 20 * MSEC_PER_SEC is always 20000. > Thus, > - If HZ is defined as 1000, 20 * MSEC_PER_SEC is 20 seconds. > - If HZ is defined as 250, 20 * MSEC_PER_SEC is 80 seconds. Could you check the patch again? The patch are using msecs_to_jiffies(20 * MSEC_PER_SEC), not 20 * MSEC_PER_SEC. msecs_to_jiffies() has done the conversion from MSEC_PER_SEC to HZ. > > So you should use 20 * HZ if you define timeout at 20 seconds. > > Thanks, > Yasuaki Ishimatsu.
