Re: [patch] mm-cleanup-1 (2.4.0)

[Zlatko Calusic]

Rik van Riel <[e-mail]> writes:

> On 7 Jan 2001, Zlatko Calusic wrote:
> 
> > The following patch cleans up some obsolete structures from the
> > mm & proc code.
> > 
> > Beside that it also fixes what I think is a bug:
> > 
> >         if ((rw == WRITE) && atomic_read(&nr_async_pages) >
> >                        pager_daemon.swap_cluster * (1 << page_cluster))
> > 
> > In that (swapout logic) it effectively says swap out 512KB at
> > once (at least on my memory configuration). I think that is a
> > little too much.
> 
> Since we submit a whole cluster of (1 << page_cluster)
> size at once, your change would mean that the VM can
> only do one IO at a time...
> 
> Have you actually measured your changes or is it just
> a gut feeling that the current default is too much?
>

Well, to be honest I didn't find any change after the modification. :)

But, anyway, Marcelo explained to me what's going on and I have
already agreed there is no need to change that. Instead I'll modify my
patch to introduce new /proc entry with meaningful name:
max_async_pages.

> (I can agree with 1/2 MB being a bit much, but doing
> just one IO at a time is probably wrong too...)
>

I can only add that I share your opinion. :)

> 
> The cleanup part of your patch is nice. I think that
> one should be submitted as soon as the 2.4 bugfix
> period is over ...
>

Right.

> (and yes, I'm not submitting any of my own trivial
> patches either unless they're REALLY needed, lets make
> sure Linus has enough time to focus on the real bugfixes)
> 

I'll check your new patch as soon as I have investigated few more
things and got a little more acquainted with the mm code in the
2.4.0. It's a pity I found some free time this late, but then again I
see myself much more involved with the mm code in the future. It's
just that I'll need some help in the start thus so much questions on
the lists. :)
-- 
Zlatko