Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::3:7 as permitted sender) client-ip=2620:137:e000::3:7;
Date:   Tue, 12 Sep 2023 17:04:59 +0100
From:   Conor Dooley <conor@kernel.org>
To:     Jisheng Zhang <jszhang@kernel.org>
Cc:     Paul Walmsley <paul.walmsley@sifive.com>,
        Palmer Dabbelt <palmer@dabbelt.com>,
        Albert Ou <aou@eecs.berkeley.edu>,
        linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] riscv: don't probe unaligned access speed if already done
Message-ID: <20230912-shakiness-denture-69165e10017b@spud>
References: <20230912154040.3306-1-jszhang@kernel.org>
MIME-Version: 1.0
Content-Type: multipart/signed; micalg=pgp-sha256;
        protocol="application/pgp-signature"; boundary="Pjl3/Zy2tSNUUoky"
Content-Disposition: inline
In-Reply-To: <20230912154040.3306-1-jszhang@kernel.org>
Precedence: bulk


--Pjl3/Zy2tSNUUoky
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
Content-Transfer-Encoding: quoted-printable

On Tue, Sep 12, 2023 at 11:40:40PM +0800, Jisheng Zhang wrote:
> If misaligned_access_speed percpu var isn't so called "HWPROBE
> MISALIGNED UNKNOWN", it means the probe has happened(this is possible
> for example, hotplug off then hotplug on one cpu), and the percpu var
> has been set, don't probe again in this case.
>=20
> Signed-off-by: Jisheng Zhang <jszhang@kernel.org>

Presumably this should grow a
Fixes: 584ea6564bca ("RISC-V: Probe for unaligned access speed")
on application.
Patch seems fine to me,
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>

Thanks,
Conor.

> ---
>  arch/riscv/kernel/cpufeature.c | 4 ++++
>  1 file changed, 4 insertions(+)
>=20
> diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeatur=
e.c
> index 1cfbba65d11a..e12cd22755c7 100644
> --- a/arch/riscv/kernel/cpufeature.c
> +++ b/arch/riscv/kernel/cpufeature.c
> @@ -568,6 +568,10 @@ void check_unaligned_access(int cpu)
>  	void *src;
>  	long speed =3D RISCV_HWPROBE_MISALIGNED_SLOW;
> =20
> +	/* We are already set since the last check */
> +	if (per_cpu(misaligned_access_speed, cpu) !=3D RISCV_HWPROBE_MISALIGNED=
_UNKNOWN)
> +		return;
> +
>  	page =3D alloc_pages(GFP_NOWAIT, get_order(MISALIGNED_BUFFER_SIZE));
>  	if (!page) {
>  		pr_warn("Can't alloc pages to measure memcpy performance");
> --=20
> 2.40.1
>=20

--Pjl3/Zy2tSNUUoky
Content-Type: application/pgp-signature; name="signature.asc"

-----BEGIN PGP SIGNATURE-----

iHUEABYIAB0WIQRh246EGq/8RLhDjO14tDGHoIJi0gUCZQCMKwAKCRB4tDGHoIJi
0u2AAQDJXOTr4V+Guyy1WrFy+wQZS9QXv/enoUWBKD8RMS/HQwD9FkWGDjRftaQq
WyroihCwFRCqRRdB5Bq1/KLYbw2ScQs=
=w02h
-----END PGP SIGNATURE-----

--Pjl3/Zy2tSNUUoky--