From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mx0b-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9BDC53128D4; Wed, 1 Jul 2026 14:22:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=148.163.158.5 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782915780; cv=none; b=Rb05C9VSgIea+3PE40EhnAQsQhs5ZLYNonN+3J6nwRIL5s0W/mp5w9qryFPP3NtPZoLFPYI9PwxjhidNjuuNPAC8TnlLmpxjg9pEcpVJAuRSCWyDdVSR5sNjPWH+I8GvMFci4AHQCiMOapYSqjOztRkKoj+EuN28kpsSPsgmxuI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782915780; c=relaxed/simple; bh=q1tnNIdtNKPOcOVd/mVinxLNP4u48O2LKaqTOqfYsMo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=BNOjA0w2mTRv93t9G+fOGS58kdqXmnpRkMkG03CYSV0lDyfgf4PiaefJ96Z5JEvAx9b4rU6bSCr9zAiu0zY6Z6caiUiuLU0UaKjbs8UuK5K+4/s2fgnXdu6YuxTN5sGdVjO5FH46M1GXh+ljED5XQCucUivP1YpJdidRi3HGdjk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.ibm.com; spf=pass smtp.mailfrom=linux.ibm.com; dkim=pass (2048-bit key) header.d=ibm.com header.i=@ibm.com header.b=EpPTnf3H; arc=none smtp.client-ip=148.163.158.5 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.ibm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.ibm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=ibm.com header.i=@ibm.com header.b="EpPTnf3H" Received: from pps.filterd (m0353725.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.18.1.11/8.18.1.11) with ESMTP id 661AIR4E494414; Wed, 1 Jul 2026 14:22:29 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=cc :content-transfer-encoding:date:from:in-reply-to:message-id :mime-version:references:subject:to; s=pp1; bh=o118WTF5A7ZjXkeCD IMxkv48WNHuVj0eP2qQB9MKsiM=; b=EpPTnf3HqdXCSZ+4m0L2/0d1Rhb0PSstS xL5sUckTzPf2vNv9SFbmdv582zEJJcvJJ5En8VmJcnkp2IHRY/BcBnb9suDByWTX TyZKAndRTtyoFG5S9JTYjuVZmjvjUIe3B1oBEVVre1xFKY69KcKCmR3jIi907mxQ TCjDuvVy2nDsuJPpNmqbqVl+haYz95msasg2NIUuK8UsEqtmS/xN9ho46FePW7t1 RM9Ko01pv7T1SLFzgBfE7AQuNUgtsiR9zmwQ5dF9Zg3fhIsbH2Oxkc0MCjJdE18X vnE/bqRvFRQJ7K1IVGSPcnMJO0kpwt0bDrnUy3E99niK1EwEWmPbg== Received: from ppma23.wdc07v.mail.ibm.com (5d.69.3da9.ip4.static.sl-reverse.com [169.61.105.93]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 4f26rf4hj7-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 01 Jul 2026 14:22:28 +0000 (GMT) Received: from pps.filterd (ppma23.wdc07v.mail.ibm.com [127.0.0.1]) by ppma23.wdc07v.mail.ibm.com (8.18.1.7/8.18.1.7) with ESMTP id 661EJh0Y008926; Wed, 1 Jul 2026 14:22:27 GMT Received: from smtprelay02.fra02v.mail.ibm.com ([9.218.2.226]) by ppma23.wdc07v.mail.ibm.com (PPS) with ESMTPS id 4f2tbhfju0-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 01 Jul 2026 14:22:27 +0000 (GMT) Received: from smtpav06.fra02v.mail.ibm.com (smtpav06.fra02v.mail.ibm.com [10.20.54.105]) by smtprelay02.fra02v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 661EMNeV49480188 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 1 Jul 2026 14:22:23 GMT Received: from smtpav06.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 685FD20049; Wed, 1 Jul 2026 14:22:23 +0000 (GMT) Received: from smtpav06.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id AEF5E20040; Wed, 1 Jul 2026 14:22:10 +0000 (GMT) Received: from li-7bb28a4c-2dab-11b2-a85c-887b5c60d769.ibm.com.com (unknown [9.67.14.28]) by smtpav06.fra02v.mail.ibm.com (Postfix) with ESMTP; Wed, 1 Jul 2026 14:22:10 +0000 (GMT) From: Shrikanth Hegde To: linux-kernel@vger.kernel.org, mingo@kernel.org, peterz@infradead.org, juri.lelli@redhat.com, vincent.guittot@linaro.org, yury.norov@gmail.com, kprateek.nayak@amd.com, iii@linux.ibm.com, corbet@lwn.net Cc: sshegde@linux.ibm.com, tglx@kernel.org, gregkh@linuxfoundation.org, pbonzini@redhat.com, seanjc@google.com, vschneid@redhat.com, huschle@linux.ibm.com, rostedt@goodmis.org, dietmar.eggemann@arm.com, maddy@linux.ibm.com, srikar@linux.ibm.com, hdanton@sina.com, chleroy@kernel.org, vineeth@bitbyteword.org, frederic@kernel.org, arighi@nvidia.com, pauld@redhat.com, christian.loehle@arm.com, tj@kernel.org, tommaso.cucinotta@gmail.com, maz@kernel.org, rafael@kernel.org, rdunlap@infradead.org, kernellwp@gmail.com, linux-doc@vger.kernel.org Subject: [PATCH v6 22/23] virt/steal_monitor: Add design check of preferred subset of active Date: Wed, 1 Jul 2026 19:46:53 +0530 Message-ID: <20260701141654.500125-23-sshegde@linux.ibm.com> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260701141654.500125-1-sshegde@linux.ibm.com> References: <20260701141654.500125-1-sshegde@linux.ibm.com> Precedence: bulk X-Mailing-List: linux-doc@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-Authority-Analysis: v=2.4 cv=a4kAM0SF c=1 sm=1 tr=0 ts=6a4522a4 cx=c_pps a=3Bg1Hr4SwmMryq2xdFQyZA==:117 a=3Bg1Hr4SwmMryq2xdFQyZA==:17 a=RAioF0-LDSMA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=V8glGbnc2Ofi9Qvn3v5h:22 a=VnNF1IyMAAAA:8 a=p3k0mxhKJztli33hioEA:9 X-Proofpoint-ORIG-GUID: vaUboH5-QiYQ6URWRTYR6w5MOnSvtjvU X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwNzAxMDE1MCBTYWx0ZWRfX+PCt8eEh+/+w 1Ggo4EgqVVarqUIsI1fsf8NQGojgEKX5xgxCY1PPhqm2AnRA1XUYq+o4nXd2HJ2rZE52JtD8A7U pZVTY4RTlp2uY1lixqkdgefvBNdudEWPqok0YBbk56KxG1vJql3WGVQqwRgAf6GKMFVuLnif4So 4A034dH/rDTftmj73SBgwQgp5+9fb6OH9g0hqBifPJ/CZpjKD3M2h0960gppMjZiU4jEFspNJ7j n0/es2fKvVniCroja6lCaQ3Dd5I1qHtsIDBQh3RieDq9XVgIDrwJV57Yv7wqNCGvq9Qpy5IT44j KlcyXMKzzcSf4ZyHVOtdzApTJCcK4UK31DIRAeRMnUkFcP0rfuK6t3VtOIJoEqXX9THIurnHfGw X2LJ+JeQJv/HR09ZszgcnLVktkZIpQs+zWmNbXJsnfcz1UKIX4GDAT3HRWQnrB2OmQ0Mj9KOuc+ /ZvhuOPbaq9MGhg8nTw== X-Proofpoint-GUID: l3ZuGsqUnZX9UqL1QmpXarrppb9yVwLY X-Proofpoint-Spam-Info: AW1haW4tMjYwNzAxMDE1MCBTYWx0ZWRfXwpseWjSKDpFN lxzPpPobjDg1DeOd4yqVm8a5Yx5wVWJCV85yxG4SNxOIgXJrZY+ZNKGihhl7RLHLQ592rGKouPR /l8B2+f73iKzDnI4J2SeAikrAyKS8f8= X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1143,Hydra:6.1.125,FMLib:17.12.100.49 definitions=2026-07-01_03,2026-06-26_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 clxscore=1015 bulkscore=0 suspectscore=0 lowpriorityscore=0 impostorscore=0 spamscore=0 priorityscore=1501 adultscore=0 malwarescore=0 phishscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2607010150 One of the main design construct that CONFIG_PREFERRED_CPU maintains is that preferred is always subset of active. Force that in any future arch specific implementations. Signed-off-by: Shrikanth Hegde --- - I am thinking to keep WARN_ON since it would enforce the policy. That's the reason i haven't used WARN_ON_ONCE. drivers/virt/steal_monitor/sm_core.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/virt/steal_monitor/sm_core.c b/drivers/virt/steal_monitor/sm_core.c index 4810bad96818..27054bd0bbf1 100644 --- a/drivers/virt/steal_monitor/sm_core.c +++ b/drivers/virt/steal_monitor/sm_core.c @@ -84,6 +84,9 @@ static void compute_preferred_cpus_work(struct work_struct *work) /* At least one core is kept as preferred */ WARN_ON(cpumask_empty(cpu_preferred_mask)); + /* Maintain design construct */ + WARN_ON(!cpumask_subset(cpu_preferred_mask, cpu_active_mask)); + /* Warn if interval_ms is set to 0, that might cause lockup. */ if (unlikely(sm_core_ctx.interval_ms == 0)) { WARN_ON(1); -- 2.47.3