Re: 2.4.9-ac1 RAID-5 resync causes PPP connection to be unusable

Andreas Dilger
2001-08-31T15:32:02Z

On Aug 30, 2001 21:23 -0700, Kevin P. Fleming wrote:
> OK, I see that now... and it looks like the risks associated with setting
> the unmaskirq flags on my drives (none of the four drives have it set now)
> are too great to be worth playing with it. I'll just not use my PPP
> connection during these particularly heavy disk activity moments. Thanks for
> the quick response.

There was a kernel patch (or possibly a user-space tool) which allowed
one to change the "priority" of IRQs and their handlers. This was back
in the 1.2 or 2.0 days, when _any_ disk or other interrupt activity might
be enough to cause problems for serial connections (especially if you
only had a 16450 UART (1 byte buffer) instead of a 16550 (16 byte buffer).
You could make your serial interrupt (handler) take priority over disk
interrupts.

Maybe Ted Ts'o or other long-time Linux folks will know what was actually
called, and whether it is still applicable to modern hardware/kernel.

Cheers, Andreas
--
Andreas Dilger \ "If a man ate a pound of pasta and a pound of antipasto,
\ would they cancel out, leaving him still hungry?"
http://www-mddsp.enel.ucalgary.ca/People/adilger/ -- Dogbert