Re: i/o stalls on 2.4.14-pre3 with ext3

From: Andrew Morton (akpm@zip.com.au)
Date: Mon Oct 29 2001 - 21:53:14 EST


David Mansfield wrote:
>
> I tried out 2.4.14-pre3 plus the ext3 patch from Andrew Morton and
> encountered some strange I/O stalls. I was doing a 'cvs tag' of my local
> kernel-cvs repository, which generates a lot of read/write traffic in a
> single process.

hmm.. Thanks - I'll do some metadata-intensive testing.

ext3's problem is that it is unable to react to VM pressure
for metadata (buffercache) pages. Once upon a time it did
do this, but we backed it out because it involved mauling
core kernel code. So at present we only react to VM pressure
for data pages.

Now that metadata pages have a backing address_space, I think we
can again allow ext3 to react to VM pressure against metadata.
It'll take some more mauling, but it's good mauling ;)

Then again, maybe something got broken in the buffer writeout
code or something.

Is this repeatable?

        while true
        do
                cvs tag foo
                cvs tag -d foo
        done

If so, can you run `top' in parallel, see if there's
anything suspicious happening?
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/



This archive was generated by hypermail 2b29 : Wed Oct 31 2001 - 21:00:38 EST