Re: 2.6.13-rc6-rt9

[Ingo Molnar <mingo@elte.hu>]

* 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