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From: Tom H. <to...@co...> - 2005-07-20 14:54:15
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In message <200...@ge...>
Christian Parpart <tr...@ge...> wrote:
> On Wednesday 20 July 2005 15:39, Nicholas Nethercote wrote:
>
>> The mmap and munmap calls are very big -- 61680GB and 69390GB
>> respectively. The fact that it happens before the usage message shows
>> this is happening very early. I guess these mmap/munmap calls are from
>> the start-up padding, but then the question is why isn't this causing
>> problems on other AMD64 systems?
>
> I'm having 2GB RAM, and 1GB swap. maybe this matters?
> Besides, why the hell is valgrind m[un]mapping such a huge space (I even
> haven't that much RAM et al)
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.
It has been known for kernels to get upset by big mappings however
which is one reason why we plan to reorganise things so that these
large mappings are not required.
Tom
--
Tom Hughes (to...@co...)
http://www.compton.nu/
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