On Fri, Jul 01, 2022 at 10:49:10AM -0700, Luis Chamberlain wrote:
On Thu, Jun 30, 2022 at 03:33:23PM -0700, Lucas De Marchi wrote:
On Thu, Jun 30, 2022 at 03:09:32PM -0700, Luis Chamberlain wrote:
> Sorry for the super late review, I was swamped. OK so the only issue
> I can think of is that rmmod *used* to support the kernel wait support
> with $(rmmod --wait) so wouldn't this be odd?
any reason not to use modprobe -r?
I was referring to old scripts which may have used $(rmmod --wait) before.
But since support for that was ripped, then yeah I can see that should
not be an issue.
However I can think of *one* issue, did we ever support `modprobe--wait`?
no
Because the way fstests / blktests would implement this feature
detection is with something like this now:
_has_modprobe_patient()
{
modprobe --help >& /dev/null || return 1
modprobe --help | grep -q -1 "remove-patiently" || return 1
return 0
}
the grep would need to be changed to something like "-w, --wait"
> It is why I had gone with:
>
> -p | --remove-patiently patiently removes the module
> -t | --timeout timeout in ms to remove the module
>
> You would know better though.
>
> Also just curious, is it really terrible to just support waiting
> forever?
is there a use case for that? If we are trying to cover some races, I
imagine a small timeout would be sufficient. Also notice that if the
timeout is too big, so will be the interval between the retries. On
your v2 I had suggested polling the refcnt so we would get notificed
on changes, but as you also noticed, that didn't work very well. So I
went back to a time-based retry solution.
if there is a use-case, should we cap the interval between retries?
I really can't think of a use case except for catching glaring
unexpected bugs in test suites where the kernel developer would
really like to know something really bad happened, but even then
a timeout is likely desirable.
yeah... if developer wants to possibly wait for a long time, `--wait -1`
is available to wait for years.
So just a heads up the timeout I'll use for fstests / blktests will be
of 100 seconds.
yeah... 100 seconds still make more sense than -1 IMO
Lucas De Marchi
Thanks for this work!
Luis
