Messages in this thread | | | Date | Thu, 30 Apr 2009 16:38:19 +0200 | From | Ingo Molnar <> | Subject | Re: [PATCH] Fix dirty page accounting in redirty_page_for_writepage() |
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* Christoph Lameter <cl@linux.com> wrote:
> On Thu, 30 Apr 2009, Ingo Molnar wrote: > > > The patch below makes the fallback/slowpath irq safe. > > Yes but sometimes you are already irq safe and such a fallback > would create significant irq/enable/disable stack operations etc > overhead for architectures that are using the fallback.
It's a fallback slowpath - non-x86 architectures should still fill in a real implementation of course.
> I think we really need another __xxx op here. Especially since > these operations are often in critical code paths.
That's a receipe for fragility: as using __xxx will still be irq-safe on x86, and 95% of the testing is done on x86, so this opens up the path to non-x86 bugs.
So we first have to see the list of architectures that _cannot_ implement an irq-safe op here via a single machine instruction. x86, ia64 and powerpc should be fine.
Ingo
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