Re: [PATCH 1/3] Separate IRQ-stacks from 4K-stacks option

From: Bill Davidsen
Date: Fri Sep 10 2004 - 13:03:20 EST


Martin J. Bligh wrote:
--Alan Cox <alan@xxxxxxxxxxxxxxxxxxx> wrote (on Friday, September 10, 2004 10:14:11 +0100):


On Gwe, 2004-09-10 at 07:40, Arjan van de Ven wrote:

Well I always assumed the future plan was to remove 8k stacks entirely;
4k+irqstacks and 8k basically have near comparable stack space, with
this patch you create an option that has more but that is/should be
deprecated. I'm not convinced that's a good idea.

Its probably appropriate to drop gcc 2.x support at that point too since
it's the major cause of remaining problems


What problems does it cause? 2.95.4 still seems to work fine for me.

The RH7.3 remnant 2.96 seems to work for me on my expendable test box, and I don't really have space for an upgrade. I haven't seen any problems, other than old systems being dog slow. And gcc3 is even slower it seems, although my machines running that have enough CPU to pretty much overpower the bloat.

I agree about killing anything but 4K stacks though - having the single
page is very compelling - not only can we allocate it easier, but we can
also use cache-hot pages from the hot list.

I have no problems with making 4k the default, but I'd really like the option of going back to 8k when I see problems, just to eliminate that as a possible cause of hangs or other instances of evil.

Is everyone claiming that everything in the kernel is 4k safe now? Or is "stable" total fiction? The 8k code doesn't take up that much space, it is well tested, and if you make 4k the default most people will try it with 4k anyway.

--
-bill davidsen (davidsen@xxxxxxx)
"The secret to procrastination is to put things off until the
last possible moment - but no longer" -me
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