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Subject: Re: [PATCH v9 04/10] x86: refcount: prevent gcc distortions
To:     Nadav Amit <namit@vmware.com>, Ingo Molnar <mingo@kernel.org>
Cc:     Ingo Molnar <mingo@redhat.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
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        Thomas Gleixner <tglx@linutronix.de>,
        Jan Beulich <JBeulich@suse.com>,
        Josh Poimboeuf <jpoimboe@redhat.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Peter Zijlstra <a.p.zijlstra@chello.nl>,
        Andy Lutomirski <luto@kernel.org>
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From:   "H. Peter Anvin" <hpa@zytor.com>
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Date:   Thu, 4 Oct 2018 13:08:25 -0700
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On 10/04/18 13:05, Nadav Amit wrote:
> 
> Funny. Immediate-patching is what I was playing with when I encountered the
> gcc issue. Performance got worse instead of improving (or at least staying
> the same), because inlining got crazy.
> 
> Anyhow, wait for my soon-to-be-sent RFC in which I define a macro called
> “call” (to reduce the retpoline overhead) before you talk about damage to
> the eyes.
> 

Doing it well is *hard*, as I discovered.  The actual patch is much,
much, larger.

	-hpa