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Subject: Re: [PATCH] livepatch: introduce klp_func called interface
From: zhang warden <zhangwarden@gmail.com>
In-Reply-To: <alpine.LSU.2.21.2405310918430.8344@pobox.suse.cz>
Date: Fri, 31 May 2024 21:19:19 +0800
Cc: Petr Mladek <pmladek@suse.com>,
 Josh Poimboeuf <jpoimboe@kernel.org>,
 Jiri Kosina <jikos@kernel.org>,
 Joe Lawrence <joe.lawrence@redhat.com>,
 live-patching@vger.kernel.org,
 LKML <linux-kernel@vger.kernel.org>
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To: Miroslav Benes <mbenes@suse.cz>


> On May 31, 2024, at 15:21, Miroslav Benes <mbenes@suse.cz> wrote:
>=20
> Hi,
>=20
> On Fri, 31 May 2024, zhang warden wrote:
>=20
> you have not replied to my questions/feedback yet.
>=20
> Also, I do not think that unlikely changes anything here. It is a =
simple=20
> branch after all.
>=20
> Miroslav
Hi Miroslav,

Sorry for my carelessness. I apologise for my ignorance.

> Second, livepatch is=20
> already use ftrace for functional replacement, I don=E2=80=99t think =
it is a=20
> good choice of using kernel tracing tool to trace a patched function.

I admit that ftrace can use for tracing the new patched function. But =
for some cases, user who what to know the state of this function can =
easily cat the 'called' interface.

It is more convenient than using ftrace to trace the state.

And for the unlikely branch, isn=E2=80=99t the complier will compile =
this branch into a cold branch that will do no harm to the function =
performance?

Regards,
Wardenjohn