Rik van Riel [off-list ref] writes:

On 7 Jan 2001, Zlatko Calusic wrote:

quoted

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
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