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

Pekka Enberg
2009-05-09T09:24:19Z

Ingo Molnar wrote:
> * Pekka Enberg <penberg@cs.helsinki.fi> wrote:
>
>> Hi Andrew,
>>
>> Andrew Morton wrote:
>>> On Fri, 08 May 2009 18:10:28 +0300
>>> Pekka Enberg <penberg@cs.helsinki.fi> 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