Re: [PATCH -v7][RFC]: mutex: implement adaptive spinning

Linus Torvalds
2009-01-08T18:00:57Z

Unrelated:

On Thu, 8 Jan 2009, Chris Mason wrote:
>
> RIP: 0010:[<ffffffff8024f4de>] [<ffffffff8024f4de>] __cmpxchg+0x36/0x3f

Ouch. HOW THE HELL DID THAT NOT GET INLINED?

cmpxchg() is a _single_ instruction if it's inlined, but it's a horrible
mess of dynamic conditionals on the (constant - per call-site) size
argument if it isn't.

It looks like you probably enabled the "let gcc mess up inlining" config
option.

Ingo - I think we need to remove that crap again. Because gcc gets the
inlining horribly horribly wrong. As usual.

Linus