linux-kernel - Re: [PATCH] kmemcheck: don't track pages allocated with interrupts disabled

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Message-ID: <19f34abd0806071118j1089d940r42440abbcf7e9829@mail.gmail.com>
Date:	Sat, 7 Jun 2008 20:18:11 +0200
From:	"Vegard Nossum" <vegard.nossum@...il.com>
To:	"Andi Kleen" <andi@...stfloor.org>
Cc:	"Pekka Enberg" <penberg@...helsinki.fi>,
	"Ingo Molnar" <mingo@...e.hu>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] kmemcheck: don't track pages allocated with interrupts disabled

On Sat, Jun 7, 2008 at 7:12 PM, Andi Kleen <andi@...stfloor.org> wrote:
> But a far better solution is to just split all the pages in  the system
> with set_memory_4k() at boot time  (and memory hot add time) when you
> know you're not in interrupt context.
>
> I believe that would be the right solution for DEBUG_PAGEALLOC too.

Ah, this is very true for more than one reason. We only ever touch
kernel pages with kmemcheck. So this means that userspace can still
use large pages and save memory with that. This wouldn't work when we
disable PSE entirely.


Vegard

-- 
"The animistic metaphor of the bug that maliciously sneaked in while
the programmer was not looking is intellectually dishonest as it
disguises that the error is the programmer's own creation."
	-- E. W. Dijkstra, EWD1036
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