linux-kernel - Re: bootmem allocator

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Message-ID: <aa79d98a0804072114q300e336eoec814ad6053c934d@mail.gmail.com>
Date:	Tue, 8 Apr 2008 08:14:13 +0400
From:	"Cyrill Gorcunov" <gorcunov@...il.com>
To:	"Yinghai Lu" <yhlu.kernel@...il.com>
Cc:	"Andi Kleen" <andi@...stfloor.org>, "Ingo Molnar" <mingo@...e.hu>,
	"H. Peter Anvin" <hpa@...or.com>,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: bootmem allocator

On Tue, Apr 8, 2008 at 1:45 AM, Yinghai Lu <yhlu.kernel@...il.com> wrote:
>
> On Mon, Apr 7, 2008 at 12:44 PM, Andi Kleen <andi@...stfloor.org> wrote:
>  >
>  > Ingo Molnar <mingo@...e.hu> writes:
>  >
>  >  > * Cyrill Gorcunov <gorcunov@...il.com> wrote:
>  >  >
>  >  >> Hi Ingo, Peter,
>  >  >>
>  >  >> small question. It was a patch recently posted which removes memset(x,
>  >  >> 0, x) after __alloc_bootmem call. There are a few another code
>  >  >> snippets who still call memset(x, 0, x). And who is responsible for
>  >  >> memory clearing? bootmem allocator or caller?
>  >  >
>  >  > 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.
>
>  add another zalloc_bootmem?
>
>  YH
>

I think it would be a good idea ;) Btw maybe would be better to call
memset on the code witch relies on "clear" memory explicitly? So we will
clear memory allocated *only* if we really need this.

Cyrill
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