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client-ip=165.204.84.17; helo=satlexmb07.amd.com; pr=C Received: from satlexmb07.amd.com (165.204.84.17) by BL02EPF00021F6F.mail.protection.outlook.com (10.167.249.11) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9542.4 via Frontend Transport; Tue, 20 Jan 2026 11:33:44 +0000 Received: from BLRKPRNAYAK.amd.com (10.180.168.240) by satlexmb07.amd.com (10.181.42.216) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.17; Tue, 20 Jan 2026 05:33:39 -0600 From: K Prateek Nayak To: Ingo Molnar , Peter Zijlstra , Juri Lelli , Vincent Guittot , CC: Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Valentin Schneider , Chen Yu , Shrikanth Hegde , "Gautham R. Shenoy" , K Prateek Nayak Subject: [PATCH v3 2/8] sched/topology: Allocate per-CPU sched_domain_shared in s_data Date: Tue, 20 Jan 2026 11:32:40 +0000 Message-ID: <20260120113246.27987-3-kprateek.nayak@amd.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260120113246.27987-1-kprateek.nayak@amd.com> References: <20260120113246.27987-1-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: satlexmb08.amd.com (10.181.42.217) To satlexmb07.amd.com (10.181.42.216) X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: BL02EPF00021F6F:EE_|IA0PPF864563BFB:EE_ X-MS-Office365-Filtering-Correlation-Id: 0d5c052e-89db-40f4-fb7b-08de5817c4b0 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|36860700013|376014|7416014|82310400026|1800799024|13003099007; X-Microsoft-Antispam-Message-Info: =?us-ascii?Q?psRvE6u3ti9l8WB3J0zXkChj94cu3OskKFKgDqI7FrBmhUuTnw2/Ih0hZmFi?= =?us-ascii?Q?u1c6EGyDO1Nw03bUFewndIseHGNOPzKsk5kilsZC0b6xaRfitUBbff8SBboy?= =?us-ascii?Q?ATiKTGmlA2M+8vhpwPFvBiRCN5b2l9+uytTn1nFRgU/hnmXZ0W1wmndIYGgV?= =?us-ascii?Q?nIVwcxbcSx98Jv9gjYI9AICmAl5TEjHuRKWpUudtSo9k/6OTMAdiJsyLDI15?= =?us-ascii?Q?R/ylzjyWvhS8HY8JKle8s3ONi93oTlF4FVu5bnSIHBEBR5P5S++VMTHVl5l0?= =?us-ascii?Q?FDHEEi0PwA9CeiGeKEA6GNeN/pf/Cl+xo6Q48s8WpFQmMLx5GYeoCJl6CO6p?= =?us-ascii?Q?UwjURV/+/brRZyBDZd4YBYNcm6uLbIk7pbIECRYjVcH2mFvsX9539jN0J6Xc?= =?us-ascii?Q?iOABJVX/e17YsqJj43ZZhUvt8LcHdl3hwMtmOV+1yK133bTceSE3cZRuDEzo?= =?us-ascii?Q?wz7xC99ng8r9aMQ9pwEtrBUsTc7e1UX04NcpYtGRpHN9Kt1eP+5DKCtFk8Aq?= =?us-ascii?Q?NPvE1Q64cBfQmL5KryHQiSbCua8nMW8hfDSoErEp8qNTETR1xj2a/O1afu8J?= =?us-ascii?Q?0ZBDrdOmVHWza+WH/GV3HYcZ7IiIavzD19y77dqI/KVCy4xOAbMZBuQ0USLg?= =?us-ascii?Q?tbIj7xmOkASyJJSMWKztKMz91NDJLdGcBpB9mn44ronab3ffQcr3myJYfQDs?= =?us-ascii?Q?ElP8CPr7k9sLgJMesx50T7CFDqx9f0xjRBHJmaaN9hH37Y42QmLP7xAfVwK1?= =?us-ascii?Q?ntrw8wfqgVada4qnlPRHLRkYddY+vGs97ix3qC3DCI5o3Y++qbm2j3ZOgS70?= =?us-ascii?Q?7ACvBEbqaniuqL9NUZuyczNEL1/+mfVBFKdD4BEqeiOHq0phkyGltaWrXN9U?= =?us-ascii?Q?zjgCn3v9sj9hyMkIG04F5VAI9QWUR7jXXj4R8ax4Lm/M6Ny95v+Zopx9Uj8m?= =?us-ascii?Q?zOABE2f0ld7bkQrtE/GXq1whNw6L6BBciro5weMA/uJxXnVhPL6QD6Ijb0GX?= =?us-ascii?Q?Mo5rmMvc+VYbuBaL/tPA2s10NNndH8wV49G5eAy3xfHrYFPrfC4+Pc6FbejP?= =?us-ascii?Q?xI6gsIbXmaUqIuFCeBFugx99oO+EXfiXg/Pmw/xXY+OMPJONB+xVtxuJnF3w?= =?us-ascii?Q?+hXLsdFxpSnJXJnNlXgdCUDzvB5RD72JJeAmxJ/MgJajOiXA+8Dl6oHQWD9m?= =?us-ascii?Q?cx7HseswSwCtwMLNZ3Gdo/3ztQapL1AAyZeqYTyEERYPxObo8JiymvN/WdZV?= =?us-ascii?Q?7+2MMXHBgdv73hxU4+rPcniDfW1Eap9mtYacAx/QjPXXo5UquPXi58bVQOii?= =?us-ascii?Q?ttSnFf2qxQ3vJMSzDLgqaOw8TvJc6TkzdI2MGejN0jey7PATzcX2rcLrKpSi?= =?us-ascii?Q?qSZcQVmd+AsFjhugmsfXr7z33E+LyV1orhzD0Poy6bWthOuGb0Lwzc/A5UbU?= =?us-ascii?Q?b4LpdZQjhHTIwsxvkCrX2GYFmjNIh02muLOkY1QTclQcOx93kjXdHCEDjBLw?= =?us-ascii?Q?8FrtdWsglMHegiv+kL/4qNk/LOmHkRBBiWnaSlIixfdW/0fkvdXtjYR84NQZ?= =?us-ascii?Q?gDyOek/vQ+LET1loLyu5lZjKu/NajLQ7XlR4mQdaIL0qNMbavIoi7vQuL7vW?= =?us-ascii?Q?E9evbX6foz18+ZP27TdYruMpftXtbYybsMsKQm2BwaGUmjN241P4ycMZqKwa?= =?us-ascii?Q?98h9QA=3D=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)(376014)(7416014)(82310400026)(1800799024)(13003099007);DIR:OUT;SFP:1101; X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 20 Jan 2026 11:33:44.0169 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 0d5c052e-89db-40f4-fb7b-08de5817c4b0 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: BL02EPF00021F6F.namprd02.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: IA0PPF864563BFB Content-Type: text/plain; charset="utf-8" The "sched_domain_shared" object is allocated for every topology level in __sdt_alloc() and is freed post sched domain rebuild if they aren't assigned during sd_init(). "sd->shared" is only assigned for SD_SHARE_LLC domains and out of all the assigned objects, only "sd_llc_shared" is ever used by the scheduler. Since only "sd_llc_shared" is ever used, and since SD_SHARE_LLC domains never overlap, allocate only a single range of per-CPU "sched_domain_shared" object with s_data instead of doing it per topology level. The subsequent commit uses the degeneration path to correctly assign the "sd->shared" to the topmost SD_SHARE_LLC domain. No functional changes are expected at this point. Signed-off-by: K Prateek Nayak Reviewed-by: Chen Yu Reviewed-by: Valentin Schneider --- Changelog rfc v2..v3: o Broke off from a single large patch. Previously https://lore.kernel.org/lkml/20251208092744.32737-3-kprateek.nayak@amd.co= m/ --- kernel/sched/topology.c | 48 ++++++++++++++++++++++++++++++++++++++++- 1 file changed, 47 insertions(+), 1 deletion(-) diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c index 649674bb6c3c..623e8835d322 100644 --- a/kernel/sched/topology.c +++ b/kernel/sched/topology.c @@ -776,6 +776,7 @@ cpu_attach_domain(struct sched_domain *sd, struct root_= domain *rd, int cpu) } =20 struct s_data { + struct sched_domain_shared * __percpu *sds; struct sched_domain * __percpu *sd; struct root_domain *rd; }; @@ -783,6 +784,7 @@ struct s_data { enum s_alloc { sa_rootdomain, sa_sd, + sa_sd_shared, sa_sd_storage, sa_none, }; @@ -1529,6 +1531,9 @@ static void set_domain_attribute(struct sched_domain = *sd, static void __sdt_free(const struct cpumask *cpu_map); static int __sdt_alloc(const struct cpumask *cpu_map); =20 +static void __sds_free(struct s_data *d, const struct cpumask *cpu_map); +static int __sds_alloc(struct s_data *d, const struct cpumask *cpu_map); + static void __free_domain_allocs(struct s_data *d, enum s_alloc what, const struct cpumask *cpu_map) { @@ -1540,6 +1545,9 @@ static void __free_domain_allocs(struct s_data *d, en= um s_alloc what, case sa_sd: free_percpu(d->sd); fallthrough; + case sa_sd_shared: + __sds_free(d, cpu_map); + fallthrough; case sa_sd_storage: __sdt_free(cpu_map); fallthrough; @@ -1555,9 +1563,11 @@ __visit_domain_allocation_hell(struct s_data *d, con= st struct cpumask *cpu_map) =20 if (__sdt_alloc(cpu_map)) return sa_sd_storage; + if (__sds_alloc(d, cpu_map)) + return sa_sd_shared; d->sd =3D alloc_percpu(struct sched_domain *); if (!d->sd) - return sa_sd_storage; + return sa_sd_shared; d->rd =3D alloc_rootdomain(); if (!d->rd) return sa_sd; @@ -2458,6 +2468,42 @@ static void __sdt_free(const struct cpumask *cpu_map) } } =20 +static int __sds_alloc(struct s_data *d, const struct cpumask *cpu_map) +{ + int j; + + d->sds =3D alloc_percpu(struct sched_domain_shared *); + if (!d->sds) + return -ENOMEM; + + for_each_cpu(j, cpu_map) { + struct sched_domain_shared *sds; + + sds =3D kzalloc_node(sizeof(struct sched_domain_shared), + GFP_KERNEL, cpu_to_node(j)); + if (!sds) + return -ENOMEM; + + *per_cpu_ptr(d->sds, j) =3D sds; + } + + return 0; +} + +static void __sds_free(struct s_data *d, const struct cpumask *cpu_map) +{ + int j; + + if (!d->sds) + return; + + for_each_cpu(j, cpu_map) + kfree(*per_cpu_ptr(d->sds, j)); + + free_percpu(d->sds); + d->sds =3D NULL; +} + static struct sched_domain *build_sched_domain(struct sched_domain_topolog= y_level *tl, const struct cpumask *cpu_map, struct sched_domain_attr *attr, struct sched_domain *child, int cpu) --=20 2.34.1