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Date:   Thu, 21 Apr 2022 10:08:59 -0400
From:   Steven Rostedt <rostedt@goodmis.org>
To:     Mark Rutland <mark.rutland@arm.com>
Cc:     Wang ShaoBo <bobo.shaobowang@huawei.com>, cj.chengjian@huawei.com,
        huawei.libin@huawei.com, xiexiuqi@huawei.com, liwei391@huawei.com,
        linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        catalin.marinas@arm.com, will@kernel.org, zengshun.wu@outlook.com
Subject: Re: [RFC PATCH -next v2 3/4] arm64/ftrace: support dynamically
 allocated trampolines
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On Thu, 21 Apr 2022 10:06:39 -0400
Steven Rostedt <rostedt@goodmis.org> wrote:

> Without this change, because the arch does not support dynamically
> allocated trampolines, it means that all these ftrace_ops will be
> registered to the same trampoline. That means, for every function that is
> traced, it will loop through all 10 of theses ftrace_ops and check their
> hashes to see if their callback should be called or not.

Oh, I forgot to mention. If you then enable function tracer that traces
*every function*, then *every function* will be going through this loop of
the 10 ftrace_ops!

With dynamically allocated trampolines, then most functions will just call
the trampoline that handles the function tracer directly.

-- Steve