Re: [PATCH 1/2] mm: Introduce GFP_PANIC for early-boot allocations

[Pekka Enberg]

Ingo Molnar wrote:
> * Pekka Enberg <penberg@xxxxxxxxxxxxxx> wrote:
>
> > Hi Andrew,
> >
> > Andrew Morton wrote:
> > > On Fri, 08 May 2009 18:10:28 +0300
> > > Pekka Enberg <penberg@xxxxxxxxxxxxxx> wrote:
> > >
> > > > +#define GFP_PANIC	(__GFP_NOFAIL | __GFP_NORETRY)
> > > urgh, you have to be kidding me.  This significantly worsens complexity
> > > and risk in core MM and it's just yuk.
> > >
> > > I think we can justify pulling such dopey party tricks to save 
> > > pageframe space, or bits in page.flags and such.  But just to 
> > > save a scrap of memory which would have been released during boot 
> > > anwyay?  Don't think so.
> > No, I wasn't kidding and I don't agree that it "significantly 
> > worsens complexity". The point is not to save memory but to 
> > clearly annotate those special call-sites that really don't need 
> > to check for out-of-memory.
>
> Frankly, i cannot believe that so many smart people dont see the 
> simple, universal, un-arguable truism in the following statement:
>
>  it is shorter, tidier, more maintainable, more reviewable to write:
>
> 	ptr = kmalloc(GFP_BOOT, size);
>
>  than to write:
>
> 	ptr = kmalloc(GFP_KERNEL, size);
> 	BUG_ON(!ptr);

Hey, that's a much better name! I guess we don't need to support 
GFP_ATOMIC? I'll repost the series with Peter's system_state != BOOTING 
warning. Lets see if that makes the patch more palatable to Andrew.

			Pekka
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