--On Wednesday, July 18, 2001 10:54:52 +0200 Mike Galbraith 
[off-list ref] wrote:

Possible solution:

Effectively reserving the last ~meg (pick a number, scaled by ramsize
would be better) of ZONE_DMA for real GFP_DMA allocations would cure
Dirk's problem I bet, and also cure most of the others too, simply by
ensuring that the ONLY thing that could unbalance that zone would be
real GFP_DMA pressure.  That way, you'd only eat the incredible cost
of balancing that zone when it really really had to be done.

Couldn't something similar to this be accomplished by tweaking the 
pages_{min,low,high} values to ZONE_DMA based on the total memory in the 
machine?  It seems to me if you have a large memory machine it'd be simple 
enough to set at least pages_high (and perhaps pages_low?) to a larger 
value.  If we do this, won't it keep the DMA zone from triggering memory 
pressure as much?

Dave McCracken

======================================================================
Dave McCracken          IBM Linux Base Kernel Team      1-512-838-3059
dmc@austin.ibm.com                                      T/L   678-3059

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