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 CD5B12F83CF; Wed, 17 Sep 2025 07:27:42 +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=1758094064; cv=none; b=jX85ksH3LN/nMhjSYphUVRcRVYXk2znTKiXdx3OiYBMmE5nNwGb46393OAJe1WRjZYQLrvXRNYg54Zik+9ljXEDCm5gdNPebQ5zyDM3LYytdc+CwCDHt/GYtBaZrtYuptgQHAKiWiP8CmWy48NTFYgkcY1IJZZt2FNq3yTms0KI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758094064; c=relaxed/simple; bh=gsFnjHZzx/dM9plsysoI8hGNXgJ+gFtacrmck6z1dc4=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=pB0zCDpSRJgdlfVhhJ0KTAIb0vdQiDdtKqxURNSRAnxzq3XLmzEZ/Js5dtneK4gpIri9QoH0xj51r8NBcraJqdQMby2iI228EnVvbfcGIEk1TqQyks/Rkn4csog7cZpPW2aWNRG9ycBzEIUZ+frjqOe4ievrqXyxwo9j9w32BXE= 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=gD0JbPxj; 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="gD0JbPxj" Received: from pps.filterd (m0360072.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.18.1.2/8.18.1.2) with ESMTP id 58GLnF4r012559; Wed, 17 Sep 2025 07:27:40 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=cc :content-type:date:from:in-reply-to:message-id:mime-version :references:subject:to; s=pp1; bh=m+mHcVZgJeGPTRzDjJv0QtBk8RGIaz Ff/BJVf0S4X1U=; b=gD0JbPxjCPNnzIeCRqLpQ4ZfOrJ5w9uXYtnoLk5SQSQbwj kbSgLxO4K9wGigeFGelseI8qGU1nKu5LUbXzx5+BWh6YBX495lq/yW9YNrR9DBJr hIX86iw43KJHK461QOeEyId06kDLnOPcAfkUdqW+4RfFBWxrdmTXb7NifwX2A4qe jnV5iTmpwwOB2FYd6oE2fmZqOaw409wIVQrs7QGh+sqAIBqptwMBx51ooBgj6wGj Ccembr+G7D9Zn69ViMtaRtVs+PcboQB6Ysg821MD9JHUO+M47PqBmKzAADOGJMGX r8o+TErcq5XCX7MXJUxS7kbvDTClbiBuZnqM+j6A== Received: from ppma11.dal12v.mail.ibm.com (db.9e.1632.ip4.static.sl-reverse.com [50.22.158.219]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 497g4n9ypx-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 17 Sep 2025 07:27:40 +0000 (GMT) Received: from pps.filterd (ppma11.dal12v.mail.ibm.com [127.0.0.1]) by ppma11.dal12v.mail.ibm.com (8.18.1.2/8.18.1.2) with ESMTP id 58H3wWUv008988; Wed, 17 Sep 2025 07:27:39 GMT Received: from smtprelay02.fra02v.mail.ibm.com ([9.218.2.226]) by ppma11.dal12v.mail.ibm.com (PPS) with ESMTPS id 495nn3fqq9-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 17 Sep 2025 07:27:39 +0000 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 58H7RZOF32375074 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 17 Sep 2025 07:27:35 GMT Received: from smtpav06.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 74CE72004D; Wed, 17 Sep 2025 07:27:35 +0000 (GMT) Received: from smtpav06.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 0BCAE2004B; Wed, 17 Sep 2025 07:27:35 +0000 (GMT) Received: from osiris (unknown [9.152.212.133]) by smtpav06.fra02v.mail.ibm.com (Postfix) with ESMTPS; Wed, 17 Sep 2025 07:27:34 +0000 (GMT) Date: Wed, 17 Sep 2025 09:27:33 +0200 From: Heiko Carstens To: Heiko Carstens Cc: Christian Borntraeger , Claudio Imbrenda , kvm@vger.kernel.org, linux-s390@vger.kernel.org, frankja@linux.ibm.com, nsg@linux.ibm.com, nrb@linux.ibm.com, seiden@linux.ibm.com, schlameuss@linux.ibm.com, svens@linux.ibm.com, agordeev@linux.ibm.com, david@redhat.com, gerald.schaefer@linux.ibm.com Subject: Re: [PATCH v2 08/20] KVM: s390: KVM page table management functions: allocation Message-ID: <20250917072733.7515Af5-hca@linux.ibm.com> References: <20250910180746.125776-1-imbrenda@linux.ibm.com> <20250910180746.125776-9-imbrenda@linux.ibm.com> <20250916162653.27229G04-hca@linux.ibm.com> <20250916184737.47224f56@p-imbrenda> <63e8c905-28b1-4e1f-be77-e0789bd75692@de.ibm.com> <20250916190514.1a3082bd@p-imbrenda> <15f451d9-ecb3-4a82-9b9a-2de64b93944d@de.ibm.com> <20250916173644.27229Kcc-hca@linux.ibm.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250916173644.27229Kcc-hca@linux.ibm.com> X-TM-AS-GCONF: 00 X-Authority-Analysis: v=2.4 cv=MN5gmNZl c=1 sm=1 tr=0 ts=68ca62ec cx=c_pps a=aDMHemPKRhS1OARIsFnwRA==:117 a=aDMHemPKRhS1OARIsFnwRA==:17 a=kj9zAlcOel0A:10 a=yJojWOMRYYMA:10 a=gwvFe6Z11aishqNQkKAA:9 a=CjuIK1q_8ugA:10 X-Proofpoint-GUID: LwMChsghrR5NP95t40TEukrGCyPeXAx3 X-Proofpoint-ORIG-GUID: LwMChsghrR5NP95t40TEukrGCyPeXAx3 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjUwOTE2MDIwNCBTYWx0ZWRfX+/R+iIPj9MD2 0WXDahAsnm8TOgYELEVPn1o5eXxPPWPwSOhAJ6EL9wj/4AyeeJi+auvQEJdzptF/QAX61mJgB3b GSlCyAfzTzrKoV3uu9Y+cbjRmkWPd7p0g7am3L0BCcWAUv+l/Xgh43c8MqkBOvxMd9wY8i7ASYN CG86OMBXUInww4+7AIkAYjwulh/wkZJVodQSggCRIZUAlf/hVQPbBECgoCk6RZ9/mAa5p9hi2Ok 9f+LBfl6q8s7c4B4ZKkZFlgnZ5z/NOFji8OWuWLNhYWDbbirShofWSrFPpOSRlM2nUYT6BKv07v GQiDPguKyb4VcGtIJhAxXTR/IwKk5Hov20mF7CvQKj0WtaYjmAcgrKdltYm0S0WivPUK/Vn6aCf YEdFwIeU X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1117,Hydra:6.1.9,FMLib:17.12.80.40 definitions=2025-09-16_02,2025-09-16_01,2025-03-28_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 clxscore=1015 spamscore=0 priorityscore=1501 bulkscore=0 impostorscore=0 malwarescore=0 adultscore=0 phishscore=0 suspectscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.19.0-2507300000 definitions=main-2509160204 On Tue, Sep 16, 2025 at 07:36:44PM +0200, Heiko Carstens wrote: > On Tue, Sep 16, 2025 at 07:06:06PM +0200, Christian Borntraeger wrote: > > > > Am 16.09.25 um 19:05 schrieb Claudio Imbrenda: > > > > > > > I think GFP_ATOMIC actually gives more guarantees? > > > > > > > > In real life GFP_ATOMIC can fail, GFP_KERNEL does not.All gfp allocation failures > > > > are usually the atomic ones. > > > > > > interesting... then I guess I need GFP_KERNEL | GFP_ATOMIC ? > > > > No. ATOMIC always means: can fail. > > So GFP_KERNEL alone is what is needed here. It is undocumented that > small GFP_KERNEL allocations will never fail (retried for ever): Another correction: it should be GFP_KERNEL_ACCOUNT instead, like it used to be before in gmap_alloc_crst() since those page tables should be accounted to the process which is allocating them.