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Date: Tue, 8 Apr 2008 17:57:42 +0400
From: Cyrill Gorcunov <gorcunov@gmail.com>
To: Andi Kleen <andi@firstfloor.org>
Cc: Ingo Molnar <mingo@elte.hu>, "H. Peter Anvin" <hpa@zytor.com>,
       LKML <linux-kernel@vger.kernel.org>, Yinghai Lu <yhlu.kernel@gmail.com>
Subject: Re: bootmem allocator
Message-ID: <20080408135742.GA7656@cvg>
References: <20080407185613.GD9211@cvg> <20080407190904.GH12292@elte.hu> <87iqytqwl7.fsf@basil.nowhere.org> <20080408080446.GA12308@elte.hu> <20080408081206.GL16647@one.firstfloor.org>
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[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@firstfloor.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
| 

OK, thanks to all of you

		- Cyrill -