Re: [RFC] mm: generic adaptive large memory allocation APIs

From: KOSAKI Motohiro
Date: Thu May 13 2010 - 00:45:51 EST


Hi

> void *kvmalloc(size_t size)
> {
> void *ptr;
>
> if (size < PAGE_SIZE)
> return kmalloc(PAGE_SIZE, GFP_KERNEL);
> ptr = alloc_pages_exact(size, GFP_KERNEL | __GFP_NOWARN);

low order GFP_KERNEL allocation never fail. then, this doesn't works
as you expected.

> if (ptr != NULL)
> return ptr;
>
> return vmalloc(size);

On x86, vmalloc area is only 128MB address space. it is very rare
resource than physical ram. vmalloc fallback is not good idea.


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