Messages in this thread | | | Date | Tue, 26 Aug 2008 00:46:07 -0700 (PDT) | Subject | Re: [Bug #11342] Linux 2.6.27-rc3: kernel BUG at mm/vmalloc.c - bisected | From | David Miller <> |
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From: Ingo Molnar <mingo@elte.hu> Date: Tue, 26 Aug 2008 09:22:20 +0200
> And i guess the next generation of 4K CPUs support should just get away > from cpumask_t-on-kernel-stack model altogether, as the current model is > not maintainable. We tried the on-kernel-stack variant, and it really > does not work reliably. We can fix this in v2.6.28.
I recenetly did some work on sparc64 to use cpumask pointers as much as possible.
The only case that didn't work was due to a limitation in arch interfaces for the new generic smp_call_function() code. It passes a cpumask_t instead of a pointer to one via arch_send_call_function_ipi().
But other than that, the whole sparc64 SMP stuff uses cpumask_t pointers only.
What it comes down to is that you have to do the "self cpu" and other tests in the cross-call dispatch routines themselves, instead of at the top-level working on cpumask_t objects.
Otherwise you have to modify cpumask_t objects and thus pluck them onto the stack where they take up silly amounts of space.
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