Re: [PATCH] sparseirq: Enable early irq_desc allocation.

From: Ingo Molnar
Date: Sat May 23 2009 - 08:58:46 EST



* Paul Mundt <lethal@xxxxxxxxxxxx> wrote:

> On Thu, May 21, 2009 at 01:26:26PM -0700, Yinghai Lu wrote:
> > can you check tip?
> > we change _cpu to node already.
> >
> > also only sh have after_bootmem now.
> > arch/sh/mm/init.c:int after_bootmem = 0;
> > arch/sh/mm/init.c: after_bootmem = 1;
> > arch/sh/mm/ioremap_64.c: extern int after_bootmem;
> > arch/sh/mm/ioremap_64.c: if (after_bootmem) {
> > include/linux/mm.h:extern int after_bootmem;
> >
> > for x86 we have bootmem_state ...
> > arch/x86/include/asm/page_types.h:enum bootmem_state {
> > arch/x86/include/asm/page_types.h:extern enum bootmem_state bootmem_state;
> > arch/x86/kernel/setup.c: bootmem_state = DURING_BOOTMEM;
> > arch/x86/mm/init.c:enum bootmem_state bootmem_state = BEFORE_BOOTMEM;
> > arch/x86/mm/init.c: if (bootmem_state == BEFORE_BOOTMEM)
> > arch/x86/mm/init.c: if (bootmem_state == BEFORE_BOOTMEM)
> > arch/x86/mm/init.c: if (bootmem_state == BEFORE_BOOTMEM && !start) {
> > arch/x86/mm/init.c: if (bootmem_state == BEFORE_BOOTMEM &&
> > arch/x86/mm/init.c: if (bootmem_state == BEFORE_BOOTMEM)
> >
> > Andrew,
> > do we need to move bootmem_state back to linux/mm.h?
>
> No need, I just switched to slab_is_available() in the respin. Here is
> v2, against -tip:

thanks.

I'm a bit unhappy about allocators here (and this is not your
fault). There's not two but _three_ states for allocation: bootmem,
pagealloc, kmalloc. There is a (short) stage during bootup where
kmalloc is not enabled yet and bootmem is already deactivated. If we
ever use slab_is_available() in such a state it will blow up.

Fixing all this allocator bootstrapping mess we have in Linux is a
lot larger project though.

Ingo
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