Messages in this thread | | | Date | Thu, 21 Mar 2019 15:50:06 -0400 | From | Steven Rostedt <> | Subject | Re: [RFC][PATCH] tracing/x86: Save CR2 before tracing irqsoff on error_entry |
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On Thu, 21 Mar 2019 20:31:52 +0100 Peter Zijlstra <peterz@infradead.org> wrote:
> > > > No I didn't. Some users only care about performance, but find memory > > cheap. > > Because cache-misses are free?
If I ever did implement this, I would try to get all the data out of line as much as possible, where only a nop would be inserted:
jmp lockdep_code raw_locking 1:
[..]
lockdep_code: do all that lockdep needs raw_locking jmp 1b
and have that converted to:
nop // jmp lockdep_code raw_locking 1:
when disabled. So the only extra pressure on the icache is the nop.
-- Steve
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