Re: [PATCH 1/2] kmemcheck v3

[Christoph Lameter <clameter@sgi.com>]

On Fri, 8 Feb 2008, Vegard Nossum wrote:

> The tracking that kmemcheck does is actually a byte-for-byte tracking
> of whether memory has been initialized or not. Think of it as valgrind
> for the kernel. We do this by "hiding" pages (marking them non-present
> for for MMU) and taking the page faults, which effectively tells us
> what memory is being attempted to be read from or written to.

Ahh. Okay. But ZONE_DMA pages are exempt from that scheme? You know 
that ZONE_NORMAL pages can undergo dma?

> I chose to implement this in the slab layer because this is probably
> where most of the interesting allocations are coming from, and this
> gives us a better control over what most users/callers care about,
> namely the specific objects.

But the slab layer allocates pages < PAGE_SIZE. You need to take a fault 
right? So each object would need its own page?