From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B1A8AC76196 for ; Fri, 7 Apr 2023 09:32:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240451AbjDGJcQ (ORCPT ); Fri, 7 Apr 2023 05:32:16 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48318 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230261AbjDGJcM (ORCPT ); Fri, 7 Apr 2023 05:32:12 -0400 Received: from mx0b-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6B00C7EC9 for ; Fri, 7 Apr 2023 02:32:11 -0700 (PDT) Received: from pps.filterd (m0127361.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.17.1.19/8.17.1.19) with ESMTP id 3379FR8I003538; Fri, 7 Apr 2023 09:31:57 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=from : to : cc : subject : date : message-id : mime-version : content-transfer-encoding; s=pp1; bh=q6v290gwEr1Tf/U83pfpXlcYWWoo5GrnSG72w+O/ClU=; b=HE8uj2pFe4nosWM5Ag8W78KIN6mes0oW6vmubneucgOyO//KwjO/ZzzxafHSYmK6cafI 6hxA0cczewpdpgqKLyDSs6Oz/QsJYAzVDJEYOZVf2vXrdNXEqN4AnOYpjDMsAQyH9YDu HvPmP03m1jClid9yeRzRiuTdr7/ilwKdfRfxbfeE3rkMtui2em7tWBXRqdLuJsi4J57i Ix6Ze67zvmzqvNs6hx+v9GoWccMznN3HJUCSK0cIpUDHaZkcAzsx9IGako/PW0a20sLy vl1+tXdSvxQ2rVOOuYG9/OAWebhpM84wywwy11PCjI1lCyxmMXQZjjqeGW0F27qeGVxa Ug== Received: from pps.reinject (localhost [127.0.0.1]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 3pta9wyfgp-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 07 Apr 2023 09:31:57 +0000 Received: from m0127361.ppops.net (m0127361.ppops.net [127.0.0.1]) by pps.reinject (8.17.1.5/8.17.1.5) with ESMTP id 3379MJGN025481; Fri, 7 Apr 2023 09:31:56 GMT Received: from ppma03ams.nl.ibm.com (62.31.33a9.ip4.static.sl-reverse.com [169.51.49.98]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 3pta9wyfg3-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 07 Apr 2023 09:31:56 +0000 Received: from pps.filterd (ppma03ams.nl.ibm.com [127.0.0.1]) by ppma03ams.nl.ibm.com (8.17.1.19/8.17.1.19) with ESMTP id 336MqZPF009513; Fri, 7 Apr 2023 09:31:54 GMT Received: from smtprelay01.fra02v.mail.ibm.com ([9.218.2.227]) by ppma03ams.nl.ibm.com (PPS) with ESMTPS id 3ppc874vjw-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 07 Apr 2023 09:31:54 +0000 Received: from smtpav06.fra02v.mail.ibm.com (smtpav06.fra02v.mail.ibm.com [10.20.54.105]) by smtprelay01.fra02v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 3379Vq6s14680578 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 7 Apr 2023 09:31:52 GMT Received: from smtpav06.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id E2C3920043; Fri, 7 Apr 2023 09:31:51 +0000 (GMT) Received: from smtpav06.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 429FF20040; Fri, 7 Apr 2023 09:31:50 +0000 (GMT) Received: from r223l.aus.stglabs.ibm.com (unknown [9.3.109.14]) by smtpav06.fra02v.mail.ibm.com (Postfix) with ESMTP; Fri, 7 Apr 2023 09:31:50 +0000 (GMT) From: Kautuk Consul To: Michael Ellerman , Nicholas Piggin , Christophe Leroy , Fabiano Rosas , Paolo Bonzini , Chao Peng , Sean Christopherson Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, Kautuk Consul Subject: [PATCH] KVM: PPC: BOOK3S: book3s_hv_nested.c: improve branch prediction for k.alloc Date: Fri, 7 Apr 2023 05:31:47 -0400 Message-Id: <20230407093147.3646597-1-kconsul@linux.vnet.ibm.com> X-Mailer: git-send-email 2.39.2 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-GUID: 4ZX3ELC14ZsoMEP1vDLm98ZtYz6ZrGba X-Proofpoint-ORIG-GUID: Fa8FAEec0Xy9rlrTrcIHqtEQ19diXjYX X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.254,Aquarius:18.0.942,Hydra:6.0.573,FMLib:17.11.170.22 definitions=2023-04-07_05,2023-04-06_03,2023-02-09_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 mlxscore=0 phishscore=0 impostorscore=0 malwarescore=0 bulkscore=0 mlxlogscore=999 spamscore=0 suspectscore=0 lowpriorityscore=0 priorityscore=1501 clxscore=1011 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2303200000 definitions=main-2304070084 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org I used the unlikely() macro on the return values of the k.alloc calls and found that it changes the code generation a bit. Optimize all return paths of k.alloc calls by improving branch prediction on return value of k.alloc. Signed-off-by: Kautuk Consul --- arch/powerpc/kvm/book3s_hv_nested.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/arch/powerpc/kvm/book3s_hv_nested.c b/arch/powerpc/kvm/book3s_hv_nested.c index 5a64a1341e6f..dbf2dd073e1f 100644 --- a/arch/powerpc/kvm/book3s_hv_nested.c +++ b/arch/powerpc/kvm/book3s_hv_nested.c @@ -446,7 +446,7 @@ long kvmhv_nested_init(void) ptb_order = 12; pseries_partition_tb = kmalloc(sizeof(struct patb_entry) << ptb_order, GFP_KERNEL); - if (!pseries_partition_tb) { + if (unlikely(!pseries_partition_tb)) { pr_err("kvm-hv: failed to allocated nested partition table\n"); return -ENOMEM; } @@ -575,7 +575,7 @@ long kvmhv_copy_tofrom_guest_nested(struct kvm_vcpu *vcpu) return H_PARAMETER; buf = kzalloc(n, GFP_KERNEL | __GFP_NOWARN); - if (!buf) + if (unlikely(!buf)) return H_NO_MEM; gp = kvmhv_get_nested(vcpu->kvm, l1_lpid, false); @@ -689,7 +689,7 @@ static struct kvm_nested_guest *kvmhv_alloc_nested(struct kvm *kvm, unsigned int long shadow_lpid; gp = kzalloc(sizeof(*gp), GFP_KERNEL); - if (!gp) + if (unlikely(!gp)) return NULL; gp->l1_host = kvm; gp->l1_lpid = lpid; @@ -1633,7 +1633,7 @@ static long int __kvmhv_nested_page_fault(struct kvm_vcpu *vcpu, /* 4. Insert the pte into our shadow_pgtable */ n_rmap = kzalloc(sizeof(*n_rmap), GFP_KERNEL); - if (!n_rmap) + if (unlikely(!n_rmap)) return RESUME_GUEST; /* Let the guest try again */ n_rmap->rmap = (n_gpa & RMAP_NESTED_GPA_MASK) | (((unsigned long) gp->l1_lpid) << RMAP_NESTED_LPID_SHIFT); -- 2.39.2