| Date | Thu, 28 Dec 2000 15:14:56 -0800 | From | "David S. Miller" <> | Subject | Re: test13-pre5 |
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Date: Fri, 29 Dec 2000 00:17:21 +0100 From: Andi Kleen <ak@suse.de>
On Thu, Dec 28, 2000 at 02:54:52PM -0800, David S. Miller wrote: > To make things like "page - mem_map" et al. use shifts instead of > expensive multiplies...
I thought that is what ->index is for ?
It is for the page cache identity Andi... you know, page_hash(mapping, index)...
And the add/sub/shift expansion of a multiply/divide by constant even in its' most optimal form is often not trivial, it is something on the order of 7 instructions with waitq debugging enabled last time I checked.
Later, David S. Miller davem@redhat.com - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org Please read the FAQ at http://www.tux.org/lkml/
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