Re: Thread implementations...

[Dean Gaudet <dgaudet-list-linux-kernel@arctic.org>]

On Thu, 25 Jun 1998, Stephen C. Tweedie wrote:

> Hi,
> 
> On 24 Jun 1998 23:56:28 -0500, ebiederm+eric@npwt.net (Eric
> W. Biederman) said:
> 
> > mmap, madvise(SEQUENTIAL),write 
> > is easy to implement.  The mmap layer already does readahead, all we
> > do is tell it not to be so conservative.
> 
> Swap readhead is also now possible.  However, madvise(SEQUENTIAL) needs
> to do much more than this; it needs to aggressively track what region of
> the vma is being actively used, and to unmap those areas no longer in
> use.

Remember it's *regions* not just a region.  An http/ftp server sends the
same file over and over and over.  There are many cursors moving
sequentially within the same file.  A threaded http/ftp server will have a
single mmap, and multiple users of that mmap. 

Dean