Re: Linux 2.6.24-rc7 Build-Failure at __you_cannot_kmalloc_that_much

From: Christoph Lameter
Date: Mon Jan 07 2008 - 13:32:06 EST


On Mon, 7 Jan 2008, Andrew Morton wrote:

> > : undefined reference to `__you_cannot_kmalloc_that_much'

There is also a kernel.org bugzilla for this at

http://bugzilla.kernel.org/show_bug.cgi?id=9669
For some reason my adds to this do not show up.

In both cases we have a

k(z/m)alloc(sizeof(*pointer), ...)

that is for some reason failing. I guess what happens is that the function
in which this occurs is too complex for gcc 3.2. Thus it stops constant
folding the sizeof(*pointer) in the complex inline-if-cascade that SLAB
needs to determine the cache and does not eliminate the
__you_cannot_kmalloc_that_much branch().

SLUB in that case just puts a series of if comparisions in the code. This
means compilation does not fail but a large amount of code is generated.

We could replace the __you_cannot_kmalloc_that_much() with a BUG()
statement so we have the same effect in SLAB?

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