Re: elevator-starvation-4 (2.2.14 && 2.3.42)

From: Jeff Garzik (jgarzik@mandrakesoft.com)
Date: Fri Feb 11 2000 - 00:59:33 EST


Bruce Thompson wrote:
>
> I tend to disagree. If we assume that cat /dev/zero > file fills
> consecutive blocks with zeroes then I would argue that the relative
> priority between the driver space handling block requests and user
> space generating requests is slightly screwy. In a case where
> requests are being generated faster than the driver can deal with
> them then no matter how we order the request queue, we've got a
> problem.
>
> I would argue that as long as the relative priority between user
> space and driver space is such that a swamped driver can handle at
> least N + 1 requests in the time that user space can generate N
> requests then we have a stable situation and the driver can
> eventually catch up and service all requests. Otherwise, I claim that
> I can come up with a pathological case for any aging scheme that will
> result in requests being starved. [...]

Surely you realize that the case where userland is generates requests
faster than the driver can fulfill is a common case...

        Jeff

-- 
Jeff Garzik         | "Vegetarian" is the Indian word
Building 1024       | for 'lousy hunter.'
MandrakeSoft, Inc.  |

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