[PATCH *] 2.4.0 VM improvements

[PATCH *] 2.4.0 VM improvements

[Rik van Riel]

Hi,

I posted a patch for the 2.4.0 VM subsystem today which
includes the following things:

- implement RSS ulimit enforcement
- make the page aging strategy sysctl tunable
	(no aging, exponential decay, linear decay)
- don't use the page age in try_to_swap_out(), since that
  function doesn't do much anyway and it saves CPU time
	(saves kswapd CPU use, but uses more swap space)
- update Documentation/sysctl/vm.txt
- simplify do_try_to_free_pages() a bit
	(no behavioural changes in the system seen)


I guess at least the documentation updates should make it into
2.4.1, the rest is rather simple and is working stable but is
not _that_ important, IMHO (so lets wait until Linus' bugfix-only
version is over and 2.4 is stable _and_ tested).

Since I'll be travelling to Australia on tuesday morning, I'll
not split this out into other things but will be porting the fair
scheduler tomorrow ... that patch will also be available on my
site.

The patch is available at this URL:

	http://www.surriel.com/patches/2.4/2.4.0-tunevm+rss

regards,

Rik
--
Virtual memory is like a game you can't win;
However, without VM there's truly nothing to loose...

		http://www.surriel.com/
http://www.conectiva.com/	http://distro.conectiva.com.br/

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Re: [PATCH *] 2.4.0 VM improvements

[Marcelo Tosatti]

On Sun, 7 Jan 2001, Rik van Riel wrote:

> The patch is available at this URL:
> 
> 	http://www.surriel.com/patches/2.4/2.4.0-tunevm+rss

I have one improvement on top of your patch.

Now its not more "rare" (as the comment on the code stated) to have
pages with page->age == 0 being called on lru_cache_add. 

This patch should make the overhead of calling lru_cache_add on pages with
page->age == 0 smaller. 

--- mm/swap.c.orig      Sun Jan  7 15:59:37 2001
+++ mm/swap.c   Sun Jan  7 16:11:21 2001
@@ -233,10 +233,12 @@
        if (!PageLocked(page))
                BUG();
        DEBUG_ADD_PAGE
-       add_page_to_active_list(page);
-       /* This should be relatively rare */
-       if (!page->age)
-               deactivate_page_nolock(page);
+
+       if (page->age)
+               add_page_to_active_list(page);
+       else
+               add_page_to_inactive_dirty_list(page);
+
        spin_unlock(&pagemap_lru_lock);
 }
 


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