linux-kernel - Re: [PATCH] trace: make ftrace likely counters atomic

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Message-ID: <20251223165640.133d61d2@gandalf.local.home>
Date: Tue, 23 Dec 2025 16:56:40 -0500
From: Steven Rostedt <rostedt@...dmis.org>
To: Khaled Saleh <khaled.saleh.req@...il.com>
Cc: mhiramat@...nel.org, mathieu.desnoyers@...icios.com,
 linux-kernel@...r.kernel.org
Subject: Re: [PATCH] trace: make ftrace likely counters atomic

On Tue, 23 Dec 2025 22:37:14 +0200
Khaled Saleh <khaled.saleh.req@...il.com> wrote:

> The correct and incorrect counters in ftrace_likely_update() are
> updated without synchronization and may race on SMP systems.

Yes, it can race, but its mostly just heuristics anyway, so missed counters
are not a problem.

> 
> Convert them to atomic counters to address the existing FIXME
> without changing behavior.

There's a reason why they are not atomic. You think I would put in a
"FIXME" if it was that easy?

Sorry, NAK.

-- Steve