Received-SPF: pass (google.com: domain of linux-kernel+bounces-13842-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:45d1:ec00::1 as permitted sender) client-ip=2604:1380:45d1:ec00::1;
Message-ID: <b441f304-a3cc-4ebe-91cb-84caf55cbfe2@web.de>
Date: Mon, 1 Jan 2024 09:56:53 +0100
Precedence: bulk
MIME-Version: 1.0
User-Agent: Mozilla Thunderbird
Subject: Re: [PATCH] cgroup/cpuset: Adjust exception handling in
 generate_sched_domains()
To: Waiman Long <longman@redhat.com>, cgroups@vger.kernel.org,
 kernel-janitors@vger.kernel.org, Johannes Weiner <hannes@cmpxchg.org>,
 Tejun Heo <tj@kernel.org>, Zefan Li <lizefan.x@bytedance.com>
Cc: LKML <linux-kernel@vger.kernel.org>
References: <53be5f98-6359-48b5-955e-fd203d99d3cb@web.de>
 <9cd1ce1d-15c7-427c-9929-f3c75b97b49c@redhat.com>
Content-Language: en-GB
From: Markus Elfring <Markus.Elfring@web.de>
In-Reply-To: <9cd1ce1d-15c7-427c-9929-f3c75b97b49c@redhat.com>
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: quoted-printable
UI-OutboundReport: notjunk:1;M01:P0:FtZC8cznO5E=;7FrmcAQ4cUKIffUX75YG7eV3iWQ
 WZY/5EGwBaJO3XpDUc6+uW8XeW6l8pAgb15FjXRgRdt1LUwrJQH49FObRb4xeGhEn84zDURxg
 4BBWALxKEmF7IbFc+KvdP9pGJNoChNH3TGh1tXD3OvWx0rwjBIevx0hC9LQqc3dHAL5EeRIbt
 esl98hUXon0HTu7EuZlK3ahwVFoSR5lQLy+54YdCiJu6RKoL/NDS9qrUH19iir11/5mNRbOyK
 nx+v8GjbtWBogBNr4Te3JLj1L9ArasTceSuCg77LUPcd9K2uylmLA+tnbiIuGJ68fbXD+xdls
 +3LurC2Vt6a1iZyZVI1Ai4ICbXTd/o29XSOQScTqzOZafttAfnVJjaLr3K9JLK0zfXsageedz
 kaXbvTICwxJRDT0XjUKO+CNpc8P1XZn1tm7zCi1hLGQZLbiRQmZxPwpvAD9/ZGGytZKeF8VxO
 Vx6MagNWO/2jdf4ovRXdpOZudsU4ErLAGmc+x3dHIdtrhrlpprAJGP0CHJM0g/iZGaeJOAMAI
 ekm7Vf4lJ+K+2MBqWx7+Ws39QxexHcdY7Azv1J0r89rCC7yrq+6q92MroKeXz0CbqtnofrPbX
 lxiYX11uksWQoLlRT6kz9CBV7jG9p14Xo5c/KJMbwUZqFY9hT7QAimQnTFFAF2Rcv6BNJFZFf
 RaGBdX1XTCRuHusXywn6h5CNgQvHgm1+c58OtXH9GxApX+jCU8KPca5qi16Xd0p9tdvETGuXI
 OooICzUxqa2q3XyooovVxEtG+KAVppVqBYUG0pJEft478DUxROzV2dnCLPhvRXiTOnZR7Eogc
 zoWalmVr9yMNvQp9fAdbFPM/Bjmcom20G59RyAxBAxQ/QUBCG0QsJfjO/HZORIwhTtLcrstdV
 0xBllrunpqGAKDiL+dt6s3YJ3XetgV/+dRHBoCg+bA8Jq6hlrccgKzgyGEwZHEYDWk/gwVDFe
 PoJG1g==

>> Two resource allocation failures triggered further actions
>> over the label =E2=80=9Cdone=E2=80=9D so far.
>>
>> * Jump to the statement =E2=80=9Cndoms =3D 1;=E2=80=9D in three cases d=
irectly
>> =C2=A0=C2=A0 by using the label =E2=80=9Cset_ndoms=E2=80=9D instead.
>>
>> * Delete an assignment for the variable =E2=80=9Cndoms=E2=80=9D in one =
if branch.
=E2=80=A6
>> ---
>> =C2=A0 kernel/cgroup/cpuset.c | 8 ++++----
>> =C2=A0 1 file changed, 4 insertions(+), 4 deletions(-)
=E2=80=A6
>> @@ -973,10 +973,9 @@ static int generate_sched_domains(cpumask_var_t **=
domains,
>>
>> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 /* Special case for the 99% of systems w=
ith one, full, sched domain */
>> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 if (root_load_balance && !top_cpuset.nr_=
subparts) {
>> -=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 ndoms =3D 1;
>> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 doms =3D alloc_s=
ched_domains(ndoms);
>> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 if (!doms)
>> -=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 got=
o done;
>> +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 got=
o set_ndoms;
>>
>> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 dattr =3D kmallo=
c(sizeof(struct sched_domain_attr), GFP_KERNEL);
>> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 if (dattr) {
=E2=80=A6
>> @@ -1123,6 +1122,7 @@ static int generate_sched_domains(cpumask_var_t *=
*domains,
>> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 * See comments in partition_sched_=
domains().
>> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 */
>> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 if (doms =3D=3D NULL)
>> +set_ndoms:
>> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 ndoms =3D 1;
>>
>> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 *domains=C2=A0=C2=A0=C2=A0 =3D doms;
=E2=80=A6
> Please clarify what this patch is for. Is it just a cleanup with no func=
tional changes or is there a bug that is being fixed?

The development opinions might vary for the presented transformation.
I suggest to reconsider the number of relevant variable assignments here.
Would you categorise an extra statement still as a desirable implementatio=
n detail?

Regards,
Markus