Re: [RFC] 2.3.39 zone balancing

On Thu, 13 Jan 2000, Rik van Riel wrote:

Now we'll only want to build something into kswapd
so that rebalancing the high memory zones is done in
the background.

You never need to rebance the bigmem between 1g and 64g withing kswapd.
This because bh/irq handlers are not going to use it. So kswapd has to
care only about the memory below the bigmem boundary.

BTW I just noticed currently (2.3.40pre1) kswapd is completly
screwedup. kswapd should still do:

		while (nr_free_pages - nr_free_bigpages < freepages.high)

exactly like in our early 2.3.18 bigmem code because _nothing_ is changed
is the basic MM design since that time.

The fix against 2.3.40pre1 to re-activate kswapd is this:

--- 2.3.40pre1/mm/vmscan.c	Sun Jan  9 20:45:31 2000
+++ /tmp/vmscan.c	Thu Jan 13 21:09:33 2000

@@ -503,7 +503,7 @@
 		do {
 			/* kswapd is critical to provide GFP_ATOMIC
 			   allocations (not GFP_HIGHMEM ones). */
-			if (nr_free_buffer_pages() >= freepages.high)
+			if (nr_free_pages() - nr_free_highpages() >= freepages.high)
 				break;
 			if (!do_try_to_free_pages(GFP_KSWAPD, 0))
 				break;

Andrea

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