Re: [PATCH -v7][RFC]: mutex: implement adaptive spinning
From: Linus Torvalds
Date: Thu Jan 08 2009 - 13:01:58 EST
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
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