Messages in this thread | | | Date | Fri, 6 Dec 2002 16:21:33 -0800 | From | William Lee Irwin III <> | Subject | Re: Maybe a VM bug in 2.4.18-18 from RH 8.0? |
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> William Lee Irwin III wrote: > > > > ... > > A 16KB or 64KB kernel allocation unit would then annihilate > On Fri, Dec 06, 2002 at 04:01:24PM -0800, Andrew Morton wrote: > You want to be careful about this: > CPU: L1 I cache: 16K, L1 D cache: 16K > Because instantiating a 16k page into user pagetables in > one hit means that it must all be zeroed. With these large > pagesizes that means that the application is likely to get > 100% L1 misses against the new page, whereas it currently > gets 100% hits.
16K is reasonable; after that one might as well go all the way. About the only way to cope is amortizing it by cacheing zeroed pages, and that has other downsides.
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