Messages in this thread | | | Date | Fri, 27 Feb 2015 15:30:08 +0100 | From | Peter Zijlstra <> | Subject | Re: [RFC][PATCH] module: Optimize __module_address() using a latched RB-tree |
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On Fri, Feb 27, 2015 at 10:32:39PM +1030, Rusty Russell wrote: > Peter Zijlstra <peterz@infradead.org> writes: > > One of the users of this is __kernel_text_address() which is employed in > > many stack unwinders; which in turn are used by perf-callchain (possibly > > from NMI context). > > Um, so the stack unwinders use "does this look like a kernel address" > because we omit the frame pointer?
Not only because of that I think; also as a general robustness check. I'm not sure people want their stack unwinder to go off into the woods.
> To keep that optimization, we add 220 non-trivial lines to module.c?
Can I make you feel better by writing more comments? I'm not sure we can convince the arch people to take this test out. Its all over the place.
> Don't get me wrong, it's cute code, but I do wonder if at some point a > grown up is going to come along and tell us to stop :)
Now where's the fun in that ;-)
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