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SubjectRe: 2.6.13-rc6-rt9

* Steven Rostedt <rostedt@goodmis.org> wrote:

> Ingo, can't you get rt.c to be more confusing. I mean it is too
> simple. We need to add a few more underscores here and there :-)
> Seriously, that rt.c is mind boggling. It was nice before, now it is
> just screaming for a cleanup (come now, do we really need the four
> underscores?). Same with latency.c.

i agree that it's ugly, but some of that ugliness is to achieve the
7-instructions fail-through codepath for the common acquire (and
release) codepath:

c03a5320 <__down_mutex>:
c03a5320: 89 c1 mov %eax,%ecx
c03a5322: 8b 15 08 76 3a c0 mov 0xc03a7608,%edx
c03a5328: 31 c0 xor %eax,%eax
c03a532a: 0f b1 51 14 cmpxchg %edx,0x14(%ecx)
c03a532e: 85 c0 test %eax,%eax
c03a5330: 75 01 jne c03a5333 <__down_mutex+0x13>
c03a5332: c3 ret

that's how much it takes to acquire an RT lock, and i worked hard to get
there. As long as the fastpath is kept this tight, feel free to do
cleanups. But i really want to avoid having to write mutex_down/up in
assembly for 24 architectures ...

Ingo
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