Re: [patch] Reset the high water marks in CPUs pcp list

Nick Piggin
2005-09-29T06:49:26Z

Christoph Lameter wrote:

>
>I know that Jack and Nick did something with those counts to insure that
>page coloring effects are avoided. Would you comment?
>
>

The 'batch' argument to setup_pageset should be clamped to a power
of 2 minus 1 (ie. 15, 31, etc), which was found to avoid the worst
of the colouring problems.

pcp->high of the hotlist IMO should have been reduced to 4 anyway
after its pcp->low was reduced from 2 to 0.

I don't see that there would be any problems with playing with the
->high and ->low numbers so long as they are a reasonable multiple
of batch, however I would question the merit of setting the high
watermark of the cold queue to ->batch + 1 (should really stay at
2*batch IMO).

Nick

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