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From: Ed Tomlinson <tomlins@cam.org>
Organization: me
To: linux-kernel@vger.kernel.org
Subject: [RFC][PATCH] vm_swap_full
Date: Sun, 4 Nov 2001 10:23:41 -0500
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Hi,

I my opinion, basing the vm_swap_full test on the size of swap is bogus.
If you have a 512M box with 128M of swap its a good idea to always release
aggressively.  If the same box has 2G of swap (has /tmp on tmpfs maybe), it
does not make sense to start the agressive release at 1G.  I suggest the 
following makes more sense.

--- linux/include/linux/swap.h.orig     Sun Nov  4 09:30:14 2001
+++ linux/include/linux/swap.h  Sun Nov  4 09:32:46 2001
@@ -80,8 +80,8 @@

 extern int nr_swap_pages;

-/* Swap 50% full? Release swapcache more aggressively.. */
-#define vm_swap_full() (nr_swap_pages*2 < total_swap_pages)
+/* Free swap less than inactive pages? Release swapcache more aggressively.. */
+#define vm_swap_full() (nr_swap_pages < nr_inactive_pages)

 extern unsigned int nr_free_pages(void);
 extern unsigned int nr_free_buffer_pages(void);

This starts aggressive swaping when the ammount of space left in swap is
less than the size of the inactive pages.

Comments?
Ed Tomlinson