Messages in this thread | | | Date | Mon, 7 Jan 2008 11:38:31 -0800 | From | Andrew Morton <> | Subject | Re: Linux 2.6.24-rc7 Build-Failure at __you_cannot_kmalloc_that_much |
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On Mon, 7 Jan 2008 10:31:53 -0800 (PST) Christoph Lameter <clameter@sgi.com> wrote:
> 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.
ug. Silent and nasty.
> We could replace the __you_cannot_kmalloc_that_much() with a BUG() > statement so we have the same effect in SLAB?
I think it'd be better to just put suitable workarounds at the offending callsites. We've only seen three or four of them in several months.
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