Re: [Lhms-devel] [PATCH 0/7] Fragmentation Avoidance V19

[Ingo Molnar]

* Rob Landley <rob@xxxxxxxxxxx> wrote:

> On Tuesday 01 November 2005 08:46, Ingo Molnar wrote:
> > how will the 100% solution handle a simple kmalloc()-ed kernel buffer,
> > that is pinned down, and to/from which live pointers may exist? That
> > alone can prevent RAM from being removable.
> 
> Would you like to apply your "100% or nothing" argument to the virtual 
> memory management subsystem and see how it sounds in that context?  
> (As an argument that we shouldn't _have_ one?)

that would be comparing apples to oranges. There is a big difference 
between "VM failures under high load", and "failure of VM functionality 
for no user-visible reason". The fragmentation problem here has nothing 
to do with pathological workloads. It has to do with 'unlucky' 
allocation patterns that pin down RAM areas which thus become 
non-removable. The RAM module will be non-removable for no user-visible 
reason. Possible under zero load, and with lots of free RAM otherwise.

	Ingo
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