Marcelo Tosatti [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.
I modified it to be a little bit more conservative and send only
(1 << page_cluster) to the swap at a time. Same applies to the
swapin_readahead() function. Comments welcome.

512kb is the maximum limit for in-flight swap pages, not the cluster size 
for IO. 

swapin_readahead actually sends requests of (1 << page_cluster) to disk
at each run.
 

OK, maybe I was too fast in concluding with that change. I'm still
trying to find out why is MM working bad in some circumstances (see my
other email to the list).

Anyway, I would than suggest to introduce another /proc entry and call
it appropriately: max_async_pages. Because that is what we care about,
anyway. I'll send another patch.
-- 
Zlatko
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