Re: upcoming kerneloops.org item: get_page_from_freelist

From: Pekka Enberg
Date: Wed Jun 24 2009 - 13:58:26 EST


Hi Andrew,

Andrew Morton wrote:
On Wed, 24 Jun 2009 19:55:24 +0300 Pekka Enberg <penberg@xxxxxxxxxxxxxx> wrote:

On Wed, Jun 24, 2009 at 7:46 PM, Andrew Morton<akpm@xxxxxxxxxxxxxxxxxxxx> wrote:
Well yes. __Using GFP_NOFAIL on a higher-order allocation is bad. __This
patch is there to find, name, shame, blame and hopefully fix callers.

A fix for cxgb3 is in the works. __slub's design is a big problem.

But we'll probably have to revert it for 2.6.31 :(
How is SLUB's design a problem here? Can't we just clear GFP_NOFAIL
from the higher order allocation and thus force GFP_NOFAIL allocations
to use the minimum required order?

That could then lead to the __GFP_NOFAIL allocation attempt returning
NULL. But the callers cannot handle that and probably don't even test
for it - this is why they used __GFP_NOFAIL.

No, the fallback allocation would still use __GFP_NOFAIL so the semantics are preserved.

Pekka
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