From: Rusty Russell <rusty@rustcorp.com.au>
To: Peter Zijlstra <peterz@infradead.org>, Andi Kleen <ak@linux.intel.com>
Cc: Andi Kleen <andi@firstfloor.org>, x86@kernel.org,
        linux-kernel@vger.kernel.org, mathieu.desnoyers@efficios.com,
        oleg@redhat.com, paulmck@linux.vnet.ibm.com, mingo@kernel.org
Subject: Re: [RFC][PATCH] module: Optimize __module_address() using a latched RB-tree
In-Reply-To: <20150226114309.GR21418@twins.programming.kicks-ass.net>
References: <1424482737-958-1-git-send-email-andi@firstfloor.org> <20150223170436.GC5029@twins.programming.kicks-ass.net> <20150223174340.GD27767@tassilo.jf.intel.com> <20150226114309.GR21418@twins.programming.kicks-ass.net>
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Date: Fri, 27 Feb 2015 22:32:39 +1030
Message-ID: <87k2z3lfz4.fsf@rustcorp.com.au>
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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?

To keep that optimization, we add 220 non-trivial lines to module.c?

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 :)

Cheers,
Rusty.
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