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From: Tom H. <to...@co...> - 2005-07-20 15:27:08
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In message <200...@ge...>
Christian Parpart <tr...@ge...> wrote:
> On Wednesday 20 July 2005 16:54, Tom Hughes wrote:
>
>> It's mapping it to stop anything else being given that part of the
>> address space - it is how valgrind controls where the OS puts stuff.
>>
>> Note that the memory will never be touched so it is an entirely
>> virtual concept and how much memory or swap you should not matter
>> in the slightest. That is why we pass the NORESERVE flag to indicate
>> that the kernel doesn't need to reserve any swap to back the mapping.
>
> Ah, I seem to understand; however, I now start wondering why the kernel takes
> so long there. Might this be a kernel bug (regarding performance)?
Probably something to do with setting up the page tables. I can't say
that I've noticed it on my amd64 box.
> Although - I'm just curious - how are you thinking of working around such
> (mis)behaviors when not using m[un]map?
There was a thread the other day where Julian and I explained about
the places to rework the address space manager so that there is no
need to maintain a rigid split of the address space.
Tom
--
Tom Hughes (to...@co...)
http://www.compton.nu/
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