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Re: ZFS L2ARC on NetBSD-9



> On 19. Apr 2021, at 19:59, Andrew Parker <andrew%pmk1.net@localhost> wrote:
> 
> On Monday, 19 April 2021 13:28:07 EDT Robert Elz wrote:
> >     Date:        Sun, 18 Apr 2021 18:58:56 +0000
> >     From:        Andrew Parker <andrew%pmk1.net@localhost>
> >     Message-ID:  <2245776.bZt9KSGgi3@t470s.local>
> >
> >   | Does anyone else have a working L2ARC?
> >
> > Sorry, don't even know what that is, and don't (currently anyway) use zfs,
> >
> > but:
> >   | -               interval = hz * l2arc_feed_secs;
> >   | +               interval = mstohz(l2arc_feed_secs);
> >
> > Are you sure about that part of the change (the earlier fragment looked
> > reasonable) ?
> >
> > mstohz() when starting with seconds (which the name of that var suggests)
> > looks like it would be much smaller than intended, whereas simply
> > multiplying seconds by hz gives ticks, which looks to be the objective in
> > all of that. Alternatively multiply secs by 1000 to generate ms, and
> > mstohz() that.
> >
> > Watch out for potential overflow in all of this though.
> >
> > kre
> 
> Oops.  I completely misread how the return value of l2arc_write_interval is used so that patch doesn't make any sense.  But adding the printf suggested earlier results in this just after boot:
> 
> [    14.600107] WARNING: ZFS on NetBSD is under development
> [    14.650039] ZFS filesystem version: 5
> [    14.650039] wait 100
> [    15.690043] wait 96
> [    17.840054] wait 0

As Manuel said this will block forever.  Please try the attached diff
that should prevent waits on negative or zero ticks.

--
J. Hannken-Illjes - hannken%eis.cs.tu-bs.de@localhost - TU Braunschweig (Germany)

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