Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Mon, 18 Apr 2022 11:37:24 +0530
From:   "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com>
Subject: Re: [PATCH v1 06/22] powerpc/ftrace: Inline ftrace_modify_code()
To:     Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Christophe Leroy <christophe.leroy@csgroup.eu>,
        Ingo Molnar <mingo@redhat.com>,
        Michael Ellerman <mpe@ellerman.id.au>,
        Paul Mackerras <paulus@samba.org>,
        Steven Rostedt <rostedt@goodmis.org>
Cc:     linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org
References: <cover.1648131740.git.christophe.leroy@csgroup.eu>
        <3b651381f4c53988ede62f4a1505e7e8ccab56b4.1648131740.git.christophe.leroy@csgroup.eu>
In-Reply-To: <3b651381f4c53988ede62f4a1505e7e8ccab56b4.1648131740.git.christophe.leroy@csgroup.eu>
MIME-Version: 1.0
User-Agent: astroid/4d6b06ad (https://github.com/astroidmail/astroid)
Message-Id: <1650261933.e8kr43zvw0.naveen@linux.ibm.com>
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Transfer-Encoding: quoted-printable
Precedence: bulk

Christophe Leroy wrote:
> Inlining ftrace_modify_code(), it increases a bit the
> size of ftrace code but brings 5% improvment on ftrace
> activation.
>=20
> Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
> ---
>  arch/powerpc/kernel/trace/ftrace.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>=20
> diff --git a/arch/powerpc/kernel/trace/ftrace.c b/arch/powerpc/kernel/tra=
ce/ftrace.c
> index 41c45b9c7f39..98e82fa4980f 100644
> --- a/arch/powerpc/kernel/trace/ftrace.c
> +++ b/arch/powerpc/kernel/trace/ftrace.c
> @@ -53,7 +53,7 @@ ftrace_call_replace(unsigned long ip, unsigned long add=
r, int link)
>  	return op;
>  }
>=20
> -static int
> +static inline int
>  ftrace_modify_code(unsigned long ip, ppc_inst_t old, ppc_inst_t new)
>  {
>  	ppc_inst_t replaced;

I thought gcc was free to inline functions without the need for=20
'inline'. Don't you see this being inlined otherwise?

On the flip side, don't we need __always_inline if we want to force=20
inlining?


- Naveen