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From:   Marco Elver <elver@google.com>
Date:   Thu, 14 May 2020 16:20:42 +0200
Message-ID: <CANpmjNPb0nr+PGRhogySdm1ixdSRTF_Xi5P8pn_8er+mDtt3kQ@mail.gmail.com>
Subject: Re: [PATCH v5 00/18] Rework READ_ONCE() to improve codegen
To:     Peter Zijlstra <peterz@infradead.org>
Cc:     Will Deacon <will@kernel.org>, LKML <linux-kernel@vger.kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        "Paul E. McKenney" <paulmck@kernel.org>,
        Ingo Molnar <mingo@kernel.org>,
        Dmitry Vyukov <dvyukov@google.com>
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On Thu, 14 May 2020 at 16:13, Peter Zijlstra <peterz@infradead.org> wrote:
>
> On Wed, May 13, 2020 at 03:58:30PM +0200, Marco Elver wrote:
> > On Wed, 13 May 2020 at 15:24, Peter Zijlstra <peterz@infradead.org> wrote:
>
> > > Also, could not this compiler instrumentation live as a kernel specific
> > > GCC-plugin instead of being part of GCC proper? Because in that case,
> > > we'd have much better control over it.
> >
> > I'd like it if we could make it a GCC-plugin for GCC, but how? I don't
> > see a way to affect TSAN instrumentation. FWIW Clang already has
> > distinguish-volatile support (unreleased Clang 11).
>
> Ah, I figured not use the built-in TSAN at all, do a complete
> replacement of the instrumentation with a plugin. AFAIU plugins are able
> to emit instrumentation, but this isn't something I know a lot about.

Interesting option. But it will likely not solve the no_sanitize and
inlining problem, because those are deeply tied to the optimization
pipelines.