Re: [PATCH] x86: introduce bootmem_state -v2

Ingo Molnar
2009-03-06T19:36:32Z

* Andrew Morton <akpm@linux-foundation.org> wrote:

> On Fri, 6 Mar 2009 20:12:49 +0100
> Ingo Molnar <mingo@elte.hu> wrote:
>
> >
> > * Yinghai Lu <yinghai@kernel.org> wrote:
> >
> > >
> > > Impact: cleanup
> > >
> > > extend after_bootmem and after_init_bootmem to bootmem_state
> > > and will have BEFORE_BOOTMEM, DURING_BOOTMEM, AFTER_BOOTMEM
> > >
> > > v2: style changes according to ingo
> > >
> > > Signed-off-by: Yinghai Lu <yinghai@kernel.org>
> > >
> > > ---
> > > arch/x86/kernel/setup.c | 1 +
> > > arch/x86/mm/init.c | 13 +++++++------
> > > arch/x86/mm/init_32.c | 28 ++++++++++++++++++++--------
> > > arch/x86/mm/init_64.c | 33 +++++++++++++++++++--------------
> > > include/linux/mm.h | 9 +++++++++
> > > 5 files changed, 56 insertions(+), 28 deletions(-)
> >
> > > Index: linux-2.6/include/linux/mm.h
> > > ===================================================================
> > > --- linux-2.6.orig/include/linux/mm.h
> > > +++ linux-2.6/include/linux/mm.h
> > > @@ -1067,6 +1067,15 @@ extern void __init mmap_init(void);
> > > extern void show_mem(void);
> > > extern void si_meminfo(struct sysinfo * val);
> > > extern void si_meminfo_node(struct sysinfo *val, int nid);
> > > +
> > > +enum bootmem_state {
> > > + BEFORE_BOOTMEM,
> > > + DURING_BOOTMEM,
> > > + AFTER_BOOTMEM
> > > +};
> > > +
> > > +extern enum bootmem_state bootmem_state;
> > > +
> > > extern int after_bootmem;
> >
> > Btw., the after_bootmem variable itself should either move to
> > x86 (and arch/sh), or should be defined in mm/bootmem.c.
> >
> > Right now we have this weird mm.h construct that is not actually
> > useful to generic code.
> >
> > Andrew, what would be your preference?
> >
>
> If two architectures are using it then it should be provided
> by core kernel?
>
> This is obvious if the state transitions are occurring in
> core-kernel code, but if the transitions are happening in arch
> code then making it a core concept assumes consistency between
> different architectures which might not exist.
>
> IOW: dunno.

Core kernel could provide a wrapper allocator which calls the
right method depending on which state we are in. It will call
bootmem_alloc() if called early, and kmalloc() if called later.
Or something like that. Would there be any utility in that?

Ingo