From: Lawrence Lin <deduce@gmail.com>
To: David Laight <david.laight.linux@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>,
Masami Hiramatsu <mhiramat@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Petr Pavlu <petr.pavlu@suse.com>,
linux-modules@vger.kernel.org, Stanislaw Gruszka <stf_xl@wp.pl>,
linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org
Subject: Re: [PATCH] ftrace: Avoid quadratic symbol lookups in ftrace_module_enable()
Date: Sun, 4 Oct 2026 12:05:59 -0500 [thread overview]
Message-ID: <20261004170600.1541723-2-deduce@gmail.com> (raw)
In-Reply-To: <20261004100030.189b1c3d@pumpkin>
On Sun, 4 Oct 2026 10:00:30 +0100, David Laight wrote:
> Surely it would be better to add the sorted index as part of module load
> so that all symbol lookups could make use of it?
A sorted index used by every lookup is roughly what [1] tried, and its
review showed what that involves: aliases, livepatch's references into
the symbol table, and the lookups by name. I'd rather leave that to the
module maintainers.
For this problem, Steve's reply suggests something smaller. The weak
locations can be dropped once at module load, so ftrace no longer looks
up symbols per record, and no index is needed. I'm prototyping that now.
next prev parent reply other threads:[~2026-10-04 17:06 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-03 16:27 Lawrence Lin via B4 Relay
2026-10-04 3:03 ` Lawrence Lin
2026-10-04 9:00 ` David Laight
2026-10-04 17:05 ` Lawrence Lin [this message]
2026-10-04 9:09 ` Steven Rostedt
2026-10-04 17:05 ` Lawrence Lin
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