Re: bootmem allocator

From: Ingo Molnar
Date: Tue Apr 08 2008 - 04:05:47 EST



* Andi Kleen <andi@xxxxxxxxxxxxxx> wrote:

> > hm, bootmem allocator is supposed to clear memory. We have a couple
> > of places that rely on that.
>
> I was actually considering to change that for the GB pages hugetlbfs
> patchkit, because memset for 1G is a little slow and not needed (will
> be cleared later anyways) and it might be a problem for very large
> systems with a lot of such pages at boot.

changing the default behavior of bootmem alloc to be non-clearing is a
really bad idea that will only cause unrobustness. The proper approach
is to add an _opt-in_ API that does not clear memory
(bootmem_alloc_dontclear() or whatever), available to callers that know
it for sure that they dont need the clearing.

Ingo
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