swsusp fails short on memory

[Felipe Alfaro Solana <felipe_alfaro@linuxmail.org>]

Hello,

I'm somewhat ignorant on the inner workings of swsusp. I have a 256MB
laptop machine running 2.6.7-rc1-bk2 + ACPI + swsusp two swap
partitions, a 256MB swap partition on /dev/hda4 plus another 256MB swap
on /dev/hda5. When trying to hibernate to disk, swsusp fails with the
following error message:

PCMCIA: socket cf71302c: *** DANGER *** unable to remove socket power
Stopping tasks:
====================================================================|
Freeing memory: ..|
/critical section: counting pages to copy.[nosave pfn
0x2f2]...............................................................
(pages needed: 46305+512=46817 free: 19214)
Suspend Machine: Couldn't get enough free pages, on 27603 pages short
Suspend Machine: Suspend failed, trying to recover...
Fixing swap signatures... ok
Restarting tasks...<4>atkbd.c: Unknown key released (translated set 2,
code 0x7a on isa0060/serio0).
atkbd.c: This is an XFree86 bug. It shouldn't access hardware directly.
 done

What I can't unserstand is how swsusp fails with "couldn't get enough
free pages". cat /proc/swaps tells:

Filename                  Type            Size    Used    Priority
/dev/hda4                 partition       281128  0       0
/dev/hda5                 partition       281096  192     1

What going on here? Why does swsusp fail when there is plenty of free
swap space?

NOTE: The same happens while only using a big, 512MB swap partition.

Thanks.