pre-100 (on ftp.kernel.org now), moves the dcache shrinking into the regular
memory de-allocation loop, and while the exact shrinking speed is probably
completely off, it should be able to react much better to small-memory machines
than the hardcoded shrink did..

Also, for those that appear to still have SMP interrupt stability
problems, Ingo pointed out that we may have problems with PCI
level-triggered interrupts. Could those people please test an additional
small patch that involves moving the "ack_APIC_irq();" inside
arch/i386/kernel/irq.c: do_ioapic_IRQ() from the top of the function to
the very bottom of that function (that will move it to outside the irq
controller lock, but it should actually be perfectly ok in this case).

                Linus