RE: free bootmem feedback patch

From: Luck, Tony <tony.luck_at_intel.com>
Date: 2004-08-07 06:09:34
>I'll go ahead and create a macro for the non-atomic bit clear. Perhaps 
>call it "ClearPageReservedNoAtomic" instead of "BootClearPageReserved"?

That looks like a more meaningful name than my suggestion.

>> Finally you have a magic "16" in the prefetchw() path.  Where did
>> it come from, and is it the right number for non-ia64 machines?
>
>My bad for not explaining that. In my limited testing of this particular 
>number it seemed to be the sweet spot for prefetching. I think it is a 
>good number for all architectures because 32 bit architectures won't 
>need the speed boost as much as 64 bit architectures. They are not 
>likely to have > 4GB memory,, in which case this function's time is 
>probably less than 1 second anyway.

There are quite a few x86 boxes running with 16GB ... but the max
is 64GB, which is still below the pain threshold for seeing an
unreasonable delay during this routine ... so I agree that perfect
tuning is irrelevent for 32-bit machines here.  You should include
your explanatory paragraph when you post to LKML.

-Tony
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Received on Fri Aug 6 16:13:24 2004

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