Re: [PATCH -v7][RFC]: mutex: implement adaptive spinning
[Posted January 14, 2009 by corbet]
| From: |
| Linus Torvalds <torvalds-AT-linux-foundation.org> |
| To: |
| Chris Mason <chris.mason-AT-oracle.com> |
| Subject: |
| Re: [PATCH -v7][RFC]: mutex: implement adaptive spinning |
| Date: |
| Thu, 8 Jan 2009 10:00:57 -0800 (PST) |
| Message-ID: |
| <alpine.LFD.2.00.0901080955400.3283@localhost.localdomain> |
| Cc: |
| Peter Zijlstra <peterz-AT-infradead.org>, Ingo Molnar <mingo-AT-elte.hu>,
Steven Rostedt <rostedt-AT-goodmis.org>,
paulmck-AT-linux.vnet.ibm.com, Gregory Haskins <ghaskins-AT-novell.com>,
Matthew Wilcox <matthew-AT-wil.cx>,
Andi Kleen <andi-AT-firstfloor.org>,
Andrew Morton <akpm-AT-linux-foundation.org>,
Linux Kernel Mailing List <linux-kernel-AT-vger.kernel.org>,
linux-fsdevel <linux-fsdevel-AT-vger.kernel.org>,
linux-btrfs <linux-btrfs-AT-vger.kernel.org>,
Thomas Gleixner <tglx-AT-linutronix.de>,
Nick Piggin <npiggin-AT-suse.de>,
Peter Morreale <pmorreale-AT-novell.com>,
Sven Dietrich <SDietrich-AT-novell.com> |
| Archive-link: |
| Article, Thread
|
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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