linux-kernel - Re: bootmem allocator

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Message-ID: <20080408173418.GD7656@cvg>
Date:	Tue, 8 Apr 2008 21:34:18 +0400
From:	Cyrill Gorcunov <gorcunov@...il.com>
To:	Andi Kleen <andi@...stfloor.org>
Cc:	Ingo Molnar <mingo@...e.hu>, "H. Peter Anvin" <hpa@...or.com>,
	LKML <linux-kernel@...r.kernel.org>,
	Yinghai Lu <yhlu.kernel@...il.com>
Subject: Re: bootmem allocator

[Andi Kleen - Tue, Apr 08, 2008 at 10:12:06AM +0200]
| On Tue, Apr 08, 2008 at 10:04:46AM +0200, Ingo Molnar wrote:
| > 
| > * Andi Kleen <andi@...stfloor.org> 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 
| 
| I was considering that too, but we have so many weird variants of bootmem
| with opt in and opt out and even combinations of both now that the whole thing 
| is starting to look really pear shaped (I admit I added some of them
| in the past myself but I'm not proud). Would be a great project for
| someone to consolidate that all a bit.
| 
| -Andi
| 

Andi, could you a bit clarify what exactly do you mean?

		- Cyrill -
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