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Shenoy" , Swapnil Sapkal , Shrikanth Hegde , Chen Yu Subject: [RESEND RFC PATCH v2 04/29] sched/fair: Simplify the entry condition for update_idle_cpu_scan() Date: Mon, 8 Dec 2025 09:26:50 +0000 Message-ID: <20251208092744.32737-4-kprateek.nayak@amd.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20251208083602.31898-1-kprateek.nayak@amd.com> References: <20251208083602.31898-1-kprateek.nayak@amd.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-ClientProxiedBy: satlexmb07.amd.com (10.181.42.216) To satlexmb07.amd.com (10.181.42.216) X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: CO1PEPF000042AA:EE_|CY8PR12MB7657:EE_ X-MS-Office365-Filtering-Correlation-Id: f8085223-4d21-4496-1975-08de363c32a6 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|36860700013|1800799024|82310400026|376014|7416014; X-Microsoft-Antispam-Message-Info: =?us-ascii?Q?YZClMxVwct+rEJaYPBcQg8/CESBDZWQw32Mwn+5fAyA1ihwPoIqPh7hPzZ4L?= =?us-ascii?Q?ve9Rm2zRFJHKdK++FkkJX4p9zJR8yZ2kffwXD2st4oJP21jlAg915x7fvPg7?= =?us-ascii?Q?q+uJ5OOKmpwTM+lciqOuvCjIeovEqepA5R7QM5/ZQYdpzoXVCJ9GA8/POQxm?= =?us-ascii?Q?3pQ63qij9MN2aniUUrtcVi+BMs+bjLftSNmA0ORGmGXYhRvMBUXNJHso39yL?= =?us-ascii?Q?fSrYDnRu8zICQo5GkVHrbwfqdbRSMobbo2Qk0I2U9DeOcEgIWsXO1D1C0CDI?= =?us-ascii?Q?f2lVXExKipSkiqXMteakI8S1VZZRYVMB/Piabjhj27DG7B9siKNSEofBfS4z?= =?us-ascii?Q?dLqDBmzECvOek9Y+uQINElEUiFVOMKMcdB5dgb3wYWi5/EVC7ioUSVrC0/U+?= =?us-ascii?Q?mi/0r9wEBlOD38NO4oXNprZvDvcevWEpTdp3s21foKV5Hl8whmFfdmbvf1/F?= =?us-ascii?Q?pCMjxjAeNUux9HG0K+UdvHHaKE+JbfuvvWBYAtZFm0XUch1ccpSWXLTvHw7F?= =?us-ascii?Q?3+LHRoV3s+xbAiLfU4KY1jTCyhrfF4Z9Gp02dquhYdfGlOHHzbBomy8vndwV?= =?us-ascii?Q?C8Nz+5g8QmCs36Nfrb7q+slRgNYJM5+aQctKO1ncZJMT08UajDhDQpjSBLEG?= =?us-ascii?Q?2DROoM4FqR4iBTa1fX1R7zZwfRSOvtg3E4FaOLya+DcKaPyyXjSC2vXhCRqZ?= =?us-ascii?Q?nilQfC5ju/LnCm5fifpZ8lzCgu56kb0qzdNHVVdTxKuK6hL6XmK7c3UTe5nE?= =?us-ascii?Q?Kfoqm8SOIfg0EPsrgyy/glNhHtZxd9wKe4+88EQEbN9lhVO243aIYdvLRExy?= =?us-ascii?Q?yoY5tEs5U7i22SaCfTKUsTKXrUo7sjz87rkJfJKnYFUAnke6CPMolOm0XzeB?= =?us-ascii?Q?MVXY92Fc7jsPuAnRIxPQ4eKThocb3GomvPbUUBwcIFwPINBZSIOzQW99lUVa?= =?us-ascii?Q?on8jlokAiduhWYyt9/qMv3ud8dbO08qp2nt8a6PvCG+afNyBSw6lzUPB5c/6?= =?us-ascii?Q?6RAoN5jqVk6Lst4+fsLKHuysYp2HpIMg7llJgIeUTqV2I0/U0D8vCwKv88db?= =?us-ascii?Q?vpmY9k/UehWu0Id1bxl498/IV4lK/mflKos1rVh4Wcbsb0NrvAi7KKRnOzon?= =?us-ascii?Q?kIPKsIuO4ikvD1wPYibBsHFeoCITJLgqRqh0eXVB2RYVLlTtLZdb8IVnHkDu?= =?us-ascii?Q?XCAoUMfqVUPz55vBb/gJOvKIdL3EGNkjNhp5hwh9ZJgv8yITZrkP8YhvY27A?= =?us-ascii?Q?2RAJk3eud+x7gY8v1PFn+I/2sV1ipqkcA/mpb3Z/Vqnqqi/jmdCYo+aMkKLv?= =?us-ascii?Q?0HYw+7FK3201Xa5q51kZUxWf2OASlJn2uR5w55Ha4D4uK+sKsZVU8SGNy3ub?= =?us-ascii?Q?GA/Rv8TkNv4SyJpF+NFmS1S2GlDXc9zGXsC8bS2qldwNZjqJZXgrlaMW3C5a?= =?us-ascii?Q?CKpFIFWdefwo3u8t8ifgW00gquz3RU8jpWrvUntDz7C6OMcIbTOSGLJ1AVtr?= =?us-ascii?Q?tR0iNf9RAWarWAtJ8I0+aZ3pS8lm95ocsc3YZ0xYO1cMQEzQMRFVErjbb26l?= =?us-ascii?Q?hYzVLCbSw2jJO2KkhTQ=3D?= X-Forefront-Antispam-Report: CIP:165.204.84.17;CTRY:US;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:satlexmb07.amd.com;PTR:InfoDomainNonexistent;CAT:NONE;SFS:(13230040)(36860700013)(1800799024)(82310400026)(376014)(7416014);DIR:OUT;SFP:1101; X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 08 Dec 2025 09:28:50.7546 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: f8085223-4d21-4496-1975-08de363c32a6 X-MS-Exchange-CrossTenant-Id: 3dd8961f-e488-4e60-8e11-a82d994e183d X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=3dd8961f-e488-4e60-8e11-a82d994e183d;Ip=[165.204.84.17];Helo=[satlexmb07.amd.com] X-MS-Exchange-CrossTenant-AuthSource: CO1PEPF000042AA.namprd03.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: CY8PR12MB7657 Content-Type: text/plain; charset="utf-8" Only the topmost SD_SHARE_LLC domain has the "sd->shared" assigned. Simply use "sd->shared" as an indicator for load balancing at the highest SD_SHARE_LLC domain in update_idle_cpu_scan() instead of relying on llc_size. Signed-off-by: K Prateek Nayak --- kernel/sched/fair.c | 10 ++++------ 1 file changed, 4 insertions(+), 6 deletions(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index b135c9ce21fe..6e1c78142536 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -11005,6 +11005,7 @@ static void update_idle_cpu_scan(struct lb_env *env, unsigned long sum_util) { struct sched_domain_shared *sd_share; + struct sched_domain *sd =3D env->sd; int llc_weight, pct; u64 x, y, tmp; /* @@ -11018,11 +11019,7 @@ static void update_idle_cpu_scan(struct lb_env *en= v, if (!sched_feat(SIS_UTIL) || env->idle =3D=3D CPU_NEWLY_IDLE) return; =20 - llc_weight =3D per_cpu(sd_llc_size, env->dst_cpu); - if (env->sd->span_weight !=3D llc_weight) - return; - - sd_share =3D rcu_dereference(per_cpu(sd_llc_shared, env->dst_cpu)); + sd_share =3D sd->shared; if (!sd_share) return; =20 @@ -11056,10 +11053,11 @@ static void update_idle_cpu_scan(struct lb_env *e= nv, */ /* equation [3] */ x =3D sum_util; + llc_weight =3D sd->span_weight; do_div(x, llc_weight); =20 /* equation [4] */ - pct =3D env->sd->imbalance_pct; + pct =3D sd->imbalance_pct; tmp =3D x * x * pct * pct; do_div(tmp, 10000 * SCHED_CAPACITY_SCALE); tmp =3D min_t(long, tmp, SCHED_CAPACITY_SCALE); --=20 2.43.0