Re: 1gb RAM + 1gb SWAP + make -j bzImage = OOM

[Stephan von Krawczynski <skraw _at_ ithnet.com>]

On Fri, 4 Jan 2002 17:24:18 -0800
Phil Oester <kernel _at_ theoesters.com> wrote:

> On Fri, Jan 04, 2002 at 04:42:43PM -0800, Nicholas Knight wrote:
> > The one catch is that -j is specified without a number.
> 
> [snip superfluous description of what 'make -j' implies]
> 
> > number, your system is dead. A user issue because it seems the user is 
> > using the option without fully comprehending the consequences.
> 
> eh?  Trust me - i understand the implications of make -j.  It's not an
unreasonable test, especially on a machine with 1gb ram/swap.  For reference,
read Rik's email regarding his reverse VM patch:> 
> http://marc.theaimsgroup.com/?l=linux-kernel&m=101007711817127&w=2
> 
> Might be enlightening

I guess this testcase is somewhat driving in the direction of Martins test with
some setis running, meaning it has a lot of standard processes that need files
and try to work out something. Can you try Martins patch at your side, redo the
-j story and give us a result? I attached it for an easy go :-)

Thanks,
Stephan

--- linux.virgin/mm/vmscan.c	Mon Dec 31 12:46:25 2001
+++ linux/mm/vmscan.c	Thu Jan  3 19:43:02 2002
@@ -394,9 +394,9 @@
 		if (PageDirty(page) && is_page_cache_freeable(page) && page->mapping) {
 			/*
 			 * It is not critical here to write it only if
-			 * the page is unmapped beause any direct writer
+			 * the page is unmapped because any direct writer
 			 * like O_DIRECT would set the PG_dirty bitflag
-			 * on the phisical page after having successfully
+			 * on the physical page after having successfully
 			 * pinned it and after the I/O to the page is finished,
 			 * so the direct writes to the page cannot get lost.
 			 */
@@ -480,11 +480,14 @@
 
 			/*
 			 * Alert! We've found too many mapped pages on the
-			 * inactive list, so we start swapping out now!
+			 * inactive list.
+			 * Move referenced pages to the active list.
 			 */
-			spin_unlock(&pagemap_lru_lock);
-			swap_out(priority, gfp_mask, classzone);
-			return nr_pages;
+			if (PageReferenced(page)) {
+				del_page_from_inactive_list(page);
+				add_page_to_active_list(page);
+			}
+			continue;
 		}
 
 		/*
@@ -521,6 +524,9 @@
 	}
 	spin_unlock(&pagemap_lru_lock);
 
+	if (max_mapped <= 0 && nr_pages > 0)
+		swap_out(priority, gfp_mask, classzone);
+
 	return nr_pages;
 }