Re: Does linux-2.2.15 have a serious disk problem? (was Re: End of first test cycle, new packages installed)
On 2000-05-25 at 14:55 +0100, Colin Watson wrote:
> Mike Bilow <mikebw@colossus.bilow.com> wrote:
> >I would not get too worried about this. Anyone running around with a
> >gigabyte or more of RAM can probably be expected to know how to do a
> >custom kernel build.
>
> Hmm, for me it's at 192Mb. Since PCs are now being sold with more memory
> than this out of the box, I don't think it's purely a high-end problem.
My reading of the problem being discussed by the kernel developers is that
the cause is associated with running out of memory arena. That is, if you
config the kernel for a maximum 1 GB RAM and you install 1 GB RAM, then
you get into trouble with forcing excessive swap in the high-end where
certain things have to reside. Linus commented that he could not
reproduce the problem on machines with 64 MB and 512 MB, which suggests
that at least he is thinking what I think he is thinking.
I have not touched hardcore kernel code like the VM stuff in years, and I
am not confident that I even understand how it works now. But there are
certain inevitable architecture-specific issues which amount to forced
trade-offs. Real Linux machines are now starting to encounter limits
imposed by the i386 architecture itself, which is a very bad sign of
things to come. We may soon find ourselves returning to the days of
bank-switching and other such tricks, although I really hope not.
If you are seeing these problems with only 192 MB RAM, then perhaps this
is a different problem than the kernel developers are looking at. I am
curious what kind of hardware you are using. This could be something
specific to the AMD Athlon CPU or the VIA chipset, for example, or to a
scatter-gather controller. Andreas said that his machine fails with
bonnie, which I think is very unlikely to be the same issue as is being
discussed by the kernel developers.
-- Mike
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