On Wednesday 31 October 2007 23:17, Peter Zijlstra wrote:

On Wed, 2007-10-31 at 21:46 +1100, Nick Piggin wrote:

quoted

And I'd prevent these ones from doing so.

Without keeping track of "reserve" pages, which doesn't feel
too clean.

The problem with that is that once a slab was allocated with the right
allocation context, anybody can get objects from these slabs.

[snip]

I understand that.

So we either reserve a page per object, which for 32 byte objects is a
large waste, or we stop anybody who doesn't have the right permissions
from obtaining objects. I took the latter approach.

What I'm saying is that the slab allocator slowpath should always
just check watermarks against the current task. Instead of this
->reserve stuff.