Messages in this thread | | | Date | Tue, 15 Jun 2010 10:12:44 +0300 | From | Avi Kivity <> | Subject | Re: [RFC/T/D][PATCH 2/2] Linux/Guest cooperative unmapped page cache control |
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On 06/14/2010 08:16 PM, Balbir Singh wrote: > * Dave Hansen<dave@linux.vnet.ibm.com> [2010-06-14 10:09:31]: > > >> On Mon, 2010-06-14 at 22:28 +0530, Balbir Singh wrote: >> >>> If you've got duplicate pages and you know >>> that they are duplicated and can be retrieved at a lower cost, why >>> wouldn't we go after them first? >>> >> I agree with this in theory. But, the guest lacks the information about >> what is truly duplicated and what the costs are for itself and/or the >> host to recreate it. "Unmapped page cache" may be the best proxy that >> we have at the moment for "easy to recreate", but I think it's still too >> poor a match to make these patches useful. >> >> > That is why the policy (in the next set) will come from the host. As > to whether the data is truly duplicated, my experiments show up to 60% > of the page cache is duplicated.
Isn't that incredibly workload dependent?
We can't expect the host admin to know whether duplication will occur or not.
-- error compiling committee.c: too many arguments to function
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