Messages in this thread |  | | | Date | Mon, 04 Mar 2002 21:38:26 -0800 | | From | "Martin J. Bligh" <> | | Subject | Re: 2.4.19pre1aa1 |
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> They're not in my tree and for very good reasons, Ben did such mistake > the first time at some point during 2.3. You've a big downside with the > per-zone information, all normal machines (like with 64M of ram or 2G of > ram) where theorical O(N) complexity is perfectly fine for lowmem > dma/normal allocations, will get hurted very much by the per-node lrus.
I'm not sure why it has to be a big impact for the "common desktop" machine - they should only have one zone anyway. ZONE_DMA should shrivel up and die in a lonely corner. Yeah, OK, keep it as a back-compatibility option for those museum pieces that need it, but personally I'd make ISA DMA support a config option defaulting to off ... maybe it's possible to do dynamically (just stick no pages in it, though I suspect it's too late by the time we know). Hardly any common desktop will need HIGHMEM support, and those that do will probably get enough kickback from per-zone things to pay for the cost.
To me, per-node would probably be about as good, but I don't think per-zone is as bad as you think.
> making it a per-lru spinlock is natural scalability optimization, > but anyways pagemap_lru_lock isn't a very critical spinlock.
see my other email - it's worse in rmap.
M.
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