Re: upcoming kerneloops.org item: get_page_from_freelist

From: Pavel Machek
Date: Tue Jun 30 2009 - 03:35:30 EST


On Sun 2009-06-28 11:01:42, Linus Torvalds wrote:
>
> On Sun, 28 Jun 2009, Pavel Machek wrote:
> >
> > Ok, so we should re-add that 4MB buffer to suspend, so that
> > allocations work even during that, right?
>
> Pavel, you really are a one-trick pony, aren't you?
>
> Give it up. Return to your pet worry when there are any actual reports. As
> you have been told several times.

How do you report something that results in black screen during
suspend in 1/100 of attempts?

> The _other_ part of memory management that you and Andrew seem to be
> ignoring is that it's very robust, and keeps extra memory around, and just
> generally does the right thing. We don't generally pre-allocate anything,
> because we don't need to.
>
> Almost the _only_ way to run out of memory is to have tons and tons of
> dirty pages around. Yes, it can happen. But if it happens, you're almost
> guaranteed to be screwed anyway. The whole VM is designed around the
> notion that most of memory is just clean caches, and it's designed around
> that simply because if it's not true, the VM freedom is so small that
> there's not a lot a VM can reasonably do.

Well, or you can have machine with not nearly enough memory (like 16MB
system), or huge 32-bit highmem system (32GB).

But it is true that I did not see OOM for quite long time.
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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