Re: 2.6.25-rc3: 34TB vmalloc total -- overflow in /proc/meminfo?

From: Pavel Machek
Date: Wed Mar 05 2008 - 16:21:40 EST


Hi!

> > > CommitLimit: 4132360 kB
> > > Committed_AS: 27684 kB
> > > VmallocTotal: 34359738367 kB
> > > VmallocUsed: 18112 kB
> > > VmallocChunk: 34359720115 kB
>
> I don't see what Pavel's issue is with this: it's simply a fact that
> with a 64-bit kernel, we've lots of virtual address space to spare
> for vmalloc. What would be surprising is for VmallocUsed to get up
> as high as that.

Hmm... ok, I see, I thought "clearly this overflowed somewhere", and I
was wrong, it is expected result.

Still.... what is 34TB of vmalloc space good for when we can only ever
allocate 4GB (because that is how much physical memory we have?)? To
prevent fragmentation?

Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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