Re: [RFC][PATCH 5/8] RSS controller task migration support

[Patrick.Le-Dot@bull.net (Patrick.Le-Dot)]

On Fri, 17 Nov 2006 22:04:08 +0530
> ...
> I am not against guarantees, but
> 
> Consider the following scenario, let's say we implement guarantees
> 
> 1. If we account for kernel resources, how do you provide guarantees
>    when you have non-reclaimable resources?

First, the current patch is based only on pages available in the
struct mm.
I doubt that these pages are "non-reclaimable"...

And guarantee should be ignored just because some kernel resources
are marked "non-reclaimable" ?


> 2. If a customer runs a system with swap turned off (which is quite
>    common),

quite common, really ?

>             then anonymous memory becomes irreclaimable. If a group
>    takes more than it's fair share (exceeds its guarantee), you
>    have scenario similar to 1 above.

That seems to be just a subset of the "guarantee+limit" model : if
guarantee is not useful for you, don't use it.

I'm not saying that guarantee should be a magic piece of code working
for everybody.

But we have to propose something for the customers who ask for a
guarantee (ie using a system with swap turned on like me and this is
quite common:-)

Patrick

+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+    Patrick Le Dot
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 Phone : +33 4 76 29 73 20               1, Rue de Provence     BP 208
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