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Mon, 12 Oct 2026 10:21:01 +0000 (GMT) Received: from li-7bb28a4c-2dab-11b2-a85c-887b5c60d769.ibm.com.com (unknown [9.124.215.77]) by smtpav04.fra02v.mail.ibm.com (Postfix) with ESMTP; Mon, 12 Oct 2026 10:21:01 +0000 (GMT) From: Shrikanth Hegde To: maddy@linux.ibm.com, linuxppc-dev@lists.ozlabs.org, peterz@infradead.org, tim.c.chen@linux.intel.com Cc: sshegde@linux.ibm.com, christophe.leroy@csgroup.eu, linux-kernel@vger.kernel.org, ritesh.list@gmail.com, kprateek.nayak@amd.com, yu.c.chen@intel.com, vineethr@linux.ibm.com, vincent.guittot@linaro.org, srikar@linux.ibm.com, npiggin@gmail.com, mpe@ellerman.id.au Subject: [PATCH 4/4] powerpc/topology: Rebuild sched domains on llc_override change Date: Mon, 12 Oct 2026 15:50:37 +0530 Message-ID: <20261012102037.2477378-5-sshegde@linux.ibm.com> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20261012102037.2477378-1-sshegde@linux.ibm.com> References: <20261012102037.2477378-1-sshegde@linux.ibm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-Reinject: loops=2 maxloops=12 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYxMDEyMDA0MCBTYWx0ZWRfX4JPSI3NXVT2j cOv1q83l0pwEEPrF9c4Lz3LIwQLNxiiYVhjEP22dFIN5rvq71DjvChpJRkQKgVNlwTuF5TEfs2n aeWSgYTwrgnRsVQeS8KH5bv2z4tTc3fD9q2Krz3BY3n68fKI4zJ3j3mOHn/TmrvkZncaf9m3AIs PxsKTXjXZWE205l1W33PalZgwI9S1LzuBPBLqCnK9/P9vLSCWzZwIWMrILPYh888CoIxM6rBxnq rRNtL5ZlLEQy2zDYXhxgtDqFD7uVM7vN0EOnO28NESYISPSBHFSdTnsDCjzZELX6svYMC7MLVvk G5QgtHPJlfFzEJyTJmfRdqdPCXm1P88aWStBbBq24ZLgTLlS4bXX4Kilv6cqHtShiVRzlX1Nmee LeA7szXpyIe5PRWQ5//gO6+BE+47iErPTWdjGrCAqT4+atwrmKQOWCojo/BdOn3P4upbBXWh0th Tu72pKdjq6+YdgpGxVA== X-Proofpoint-Spam-Info: AW1haW4tMjYxMDEyMDA0MCBTYWx0ZWRfXwdxou7C2f4un SK0DIlE2CdzcatUOXvSxGXVrtMiy1DoY5vxw6ZRj12w6I0GZ8A5gOvteCtdkFEG7L8ArP0XobtS d/ILFZNTsjwd3dfl3mj01tMgh/4qThM= X-Proofpoint-ORIG-GUID: 4Pa8r40YIwhySoGg7EA6RM6_reRZJIMN X-Authority-Analysis: v=2.4 cv=a6KlZkSF c=1 sm=1 tr=0 ts=6accb497 cx=c_pps a=AfN7/Ok6k8XGzOShvHwTGQ==:117 a=AfN7/Ok6k8XGzOShvHwTGQ==:17 a=660iZSQnnn4A:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=V8glGbnc2Ofi9Qvn3v5h:22 a=VnNF1IyMAAAA:8 a=VoiLvOrikwrOPNCf7twA:9 X-Proofpoint-GUID: sWDCCqh9Iy2EYwirXgS20nHHvOUk79Jv X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1176,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-10-12_03,2026-10-09_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 bulkscore=0 malwarescore=0 spamscore=0 suspectscore=0 clxscore=1015 phishscore=0 priorityscore=1501 lowpriorityscore=0 impostorscore=0 adultscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2610080000 definitions=main-2610120040 On changing the llc_override, rebuild the sched domains. For the rebuild to happen, indicate it to the scheduler that complete rebuild of the sched domains need to happen via arch_update_cpu_topology(). With this, llc_override functionality is complete. For example, on CPU10, domain0/name:SMT domain1/name:MC domain2/name:PKG echo 0 > /sys/kernel/debug/powerpc/llc_override SD_BALANCE_NEWIDLE SD_BALANCE_EXEC SD_BALANCE_FORK SD_WAKE_AFFINE SD_SHARE_CPUCAPACITY SD_SHARE_LLC SD_PREFER_SIBLING SD_BALANCE_NEWIDLE SD_BALANCE_EXEC SD_BALANCE_FORK SD_WAKE_AFFINE SD_PREFER_SIBLING SD_BALANCE_NEWIDLE SD_BALANCE_EXEC SD_BALANCE_FORK SD_WAKE_AFFINE SD_PREFER_SIBLING echo mc > /sys/kernel/debug/powerpc/llc_override SD_BALANCE_NEWIDLE SD_BALANCE_EXEC SD_BALANCE_FORK SD_WAKE_AFFINE SD_SHARE_CPUCAPACITY SD_SHARE_LLC SD_PREFER_SIBLING SD_BALANCE_NEWIDLE SD_BALANCE_EXEC SD_BALANCE_FORK SD_WAKE_AFFINE SD_SHARE_LLC SD_PREFER_SIBLING SD_BALANCE_NEWIDLE SD_BALANCE_EXEC SD_BALANCE_FORK SD_WAKE_AFFINE SD_PREFER_SIBLING Signed-off-by: Shrikanth Hegde --- arch/powerpc/kernel/smp.c | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-) diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c index 4b6512d25f73..6a4ee7d3b8e5 100644 --- a/arch/powerpc/kernel/smp.c +++ b/arch/powerpc/kernel/smp.c @@ -37,6 +37,7 @@ #include #include #include +#include #include #include @@ -1863,6 +1864,16 @@ void __noreturn arch_cpu_idle_dead(void) #endif +int arch_update_cpu_topology(void) +{ + if (READ_ONCE(llc_override_changed)) { + WRITE_ONCE(llc_override_changed, 0); + return 1; + } + + return 0; +} + static ssize_t llc_override_get(struct file *file, char __user *ubuf, size_t count, loff_t *ppos) { @@ -1909,10 +1920,10 @@ static ssize_t llc_override_set(struct file *file, const char __user *ubuf, if (override != READ_ONCE(llc_override)) { WRITE_ONCE(llc_override, override); WRITE_ONCE(llc_override_changed, 1); - pr_info("sched LLC override set to %s\n", + pr_info("sched LLC override set to %s. Rebuilding sched domains\n", llc_override_str[override]); - /* Will be calling rebuild sched domain in later patches */ + rebuild_sched_domains(); } mutex_unlock(&llc_override_mutex); -- 2.52.0