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Date: Thu, 22 Jan 2026 07:25:54 +0100
From: Christoph Hellwig <hch@lst.de>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>, Christoph Hellwig <hch@lst.de>,
	Marco Elver <elver@google.com>, Ingo Molnar <mingo@kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>, Will Deacon <will@kernel.org>,
	Boqun Feng <boqun.feng@gmail.com>, Waiman Long <longman@redhat.com>,
	linux-kernel@vger.kernel.org, llvm@lists.linux.dev,
	Bart Van Assche <bvanassche@acm.org>
Subject: Re: [PATCH tip/locking/core] compiler-context-analysis: Support
 immediate acquisition after initialization
Message-ID: <20260122062554.GA24403@lst.de>
References: <20260115005231.1211866-1-elver@google.com> <20260115213311.GG830755@noisy.programming.kicks-ass.net> <aWmRlXZaOOUvU_Nv@elver.google.com> <20260116150750.GG831050@noisy.programming.kicks-ass.net> <20260116151043.GA18805@lst.de> <20260116152016.GI831050@noisy.programming.kicks-ass.net> <20260116152741.GA19823@lst.de> <20260116154754.GN830755@noisy.programming.kicks-ass.net> <20260121202427.099c36ab@gandalf.local.home>
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On Wed, Jan 21, 2026 at 08:24:27PM -0500, Steven Rostedt wrote:
> I haven't seen all the other approaches, but would a macro be able to hide
> it with some kind of obfuscation from the compiler?
> 
> 
> 	GUARD_INIT(obj->state, INIT_STATE);
> 
> which would be something like a WRITE_ONCE() macro. I'm not sure what
> tooling there is to disable checks for a small bit of code like this.

Well, you don't really want WRITE_ONCE for every field, but basically
a barrier.  And initializing the lock seems like a very logical
place for such a barrier.  So we'd probably need to pair it with a some
kind of 'start initializing fields' that starts the context, and the
init then ends it.