bug 193400: sfbuf changes on mips32 may have exposed some vm/pmap issues on mips32?

[Alan Cox]

On 09/06/2014 17:24, Adrian Chadd wrote:
> Hi!
>
> This bug:
>
> https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=193400
>
> is what I reported to alc a couple weeks ago as breaking on my 128mb
> RAM mipsbe board.
>
> It turns out that the difference between the MIPS32 sfbuf code and the
> new stuff gleb added was the refcounting side of things. With the MIPS
> code, there was no refcounting at all - each sfbuf allocation would
> allocate a new sfbuf. Now, I don't know how correct that is (my
> reading of the code is "not correct!") but it wasn't panicing things.
>
> So I think maybe gleb's patch to sfbuf exposed a MIPS32 pmap/VM bug?
>
> Alan - how would we go about figuring out what could be the issue here?

I just sent you an email a few minutes ago describing how to restore the
old behavior.

> I'd really appreciate some help here as I'd like to keep the MIPS32
> stuff in good shape. :)
>
> Thanks!
>
>
> -a
>