linux-kernel - Re: [PATCH v3] tracing: Guard __DECLARE_TRACE() use of __DO_TRACE

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <20251213012050.576eead3@fedora>
Date: Sat, 13 Dec 2025 01:20:50 -0500
From: Steven Rostedt <rostedt@...dmis.org>
To: Mathieu Desnoyers <mathieu.desnoyers@...icios.com>
Cc: "Paul E. McKenney" <paulmck@...nel.org>, Joel Fernandes
 <joelagnelf@...dia.com>, "linux-kernel@...r.kernel.org"
 <linux-kernel@...r.kernel.org>, Sebastian Andrzej Siewior
 <bigeasy@...utronix.de>, "bpf@...r.kernel.org" <bpf@...r.kernel.org>,
 Thomas Gleixner <tglx@...utronix.de>
Subject: Re: [PATCH v3] tracing: Guard __DECLARE_TRACE() use of
 __DO_TRACE_CALL() with SRCU-fast

On Fri, 12 Dec 2025 23:19:41 -0500
Mathieu Desnoyers <mathieu.desnoyers@...icios.com> wrote:

> Here is one additional thing to keep in mind: although
> SRCU-fast is probably quite fast (as the name implies),
> last time I tried using migrate disable in a fast path
> I was surprised to see verbosity of the generated assembly,
> and how slow it was compared to preempt disable.
> 
> So before using migrate disable on a fast path, at least on
> non-preempt-RT configs, we should carefully consider the
> performance impact of migrate disable.

Right, which is another reason I'm keeping that part of the patch as-is.

-- Steve