Re: nr_async_pages and swapin readahead on -ac series

["Stephen C. Tweedie" <sct@redhat.com>]

Hi,

On Wed, Mar 07, 2001 at 10:57:21PM -0300, Marcelo Tosatti wrote:
>  
> On the latest 2.4 -ac series, nr_async_pages is only being used to count
> swap outs, and not for both swap reads and writes (as Linus tree does).

Seems fine to me.

> The problem is that nr_async_pages is used to limit swapin readahead based
> on the number of on flight swap pages (mm/memory.c::swapin_readahead):

That's probably a mistake: we don't throttle readahead on normal files
in this manner.

Swapin is always synchronous: it happens in response to a task's page
fault.  As such it is always going to be rate-limited automatically.
I don't think it's too important to count reads in nr_async_pages, nor
to throttle readaheads if nr_async_pages is too large.

Cheers,
 Stephen
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