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 X-Spam-Level: X-Spam-Status: No, score=-8.3 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0223DC5DF63 for ; Wed, 6 Nov 2019 15:57:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B62AD2178F for ; Wed, 6 Nov 2019 15:57:21 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="SE0Amoov" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732192AbfKFP5U (ORCPT ); Wed, 6 Nov 2019 10:57:20 -0500 Received: from us-smtp-2.mimecast.com ([205.139.110.61]:54606 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727028AbfKFP5U (ORCPT ); Wed, 6 Nov 2019 10:57:20 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1573055837; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references:openpgp:openpgp:autocrypt:autocrypt; bh=4XBocO404UvJWNVCOgyaoQws+FJzp3wcDLJ3PBROiUg=; b=SE0AmoovR1g+CQXL6FS9B/ITGkST1Ji2uynG0Kl0zg1twn4oimcWAtMrHH4OOwhWpe3nG6 O5YLg3Oxl9gnA00xSQrR05xQFaVF7hiAHE1Leha/7TI7nTclynNsToHb93X72i205gdJ5S s4PEmwldd0WJTqKYISI9CMhg8HpYmk8= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-216-etHT-JttOmWv7bYQ2r2Z_w-1; Wed, 06 Nov 2019 10:57:16 -0500 X-MC-Unique: etHT-JttOmWv7bYQ2r2Z_w-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 8B7E2107ACC3; Wed, 6 Nov 2019 15:57:14 +0000 (UTC) Received: from [10.18.17.163] (dhcp-17-163.bos.redhat.com [10.18.17.163]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 0013A600D3; Wed, 6 Nov 2019 15:57:06 +0000 (UTC) Subject: Re: [Patch v1 1/2] KVM: remember position in kvm->vcpus array To: Sean Christopherson Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, pbonzini@redhat.com, mtosatti@redhat.com, rkrcmar@redhat.com, vkuznets@redhat.com, wanpengli@tencent.com, jmattson@google.com, joro@8bytes.org References: <1573047398-7665-1-git-send-email-nitesh@redhat.com> <1573047398-7665-2-git-send-email-nitesh@redhat.com> <20191106144326.GA16249@linux.intel.com> From: Nitesh Narayan Lal Openpgp: preference=signencrypt Autocrypt: addr=nitesh@redhat.com; prefer-encrypt=mutual; keydata= mQINBFl4pQoBEADT/nXR2JOfsCjDgYmE2qonSGjkM1g8S6p9UWD+bf7YEAYYYzZsLtbilFTe z4nL4AV6VJmC7dBIlTi3Mj2eymD/2dkKP6UXlliWkq67feVg1KG+4UIp89lFW7v5Y8Muw3Fm uQbFvxyhN8n3tmhRe+ScWsndSBDxYOZgkbCSIfNPdZrHcnOLfA7xMJZeRCjqUpwhIjxQdFA7 n0s0KZ2cHIsemtBM8b2WXSQG9CjqAJHVkDhrBWKThDRF7k80oiJdEQlTEiVhaEDURXq+2XmG jpCnvRQDb28EJSsQlNEAzwzHMeplddfB0vCg9fRk/kOBMDBtGsTvNT9OYUZD+7jaf0gvBvBB lbKmmMMX7uJB+ejY7bnw6ePNrVPErWyfHzR5WYrIFUtgoR3LigKnw5apzc7UIV9G8uiIcZEn C+QJCK43jgnkPcSmwVPztcrkbC84g1K5v2Dxh9amXKLBA1/i+CAY8JWMTepsFohIFMXNLj+B RJoOcR4HGYXZ6CAJa3Glu3mCmYqHTOKwezJTAvmsCLd3W7WxOGF8BbBjVaPjcZfavOvkin0u DaFvhAmrzN6lL0msY17JCZo046z8oAqkyvEflFbC0S1R/POzehKrzQ1RFRD3/YzzlhmIowkM BpTqNBeHEzQAlIhQuyu1ugmQtfsYYq6FPmWMRfFPes/4JUU/PQARAQABtCVOaXRlc2ggTmFy YXlhbiBMYWwgPG5pbGFsQHJlZGhhdC5jb20+iQI9BBMBCAAnBQJZeKUKAhsjBQkJZgGABQsJ CAcCBhUICQoLAgQWAgMBAh4BAheAAAoJEKOGQNwGMqM56lEP/A2KMs/pu0URcVk/kqVwcBhU SnvB8DP3lDWDnmVrAkFEOnPX7GTbactQ41wF/xwjwmEmTzLrMRZpkqz2y9mV0hWHjqoXbOCS 6RwK3ri5e2ThIPoGxFLt6TrMHgCRwm8YuOSJ97o+uohCTN8pmQ86KMUrDNwMqRkeTRW9wWIQ EdDqW44VwelnyPwcmWHBNNb1Kd8j3xKlHtnS45vc6WuoKxYRBTQOwI/5uFpDZtZ1a5kq9Ak/ MOPDDZpd84rqd+IvgMw5z4a5QlkvOTpScD21G3gjmtTEtyfahltyDK/5i8IaQC3YiXJCrqxE r7/4JMZeOYiKpE9iZMtS90t4wBgbVTqAGH1nE/ifZVAUcCtycD0f3egX9CHe45Ad4fsF3edQ ESa5tZAogiA4Hc/yQpnnf43a3aQ67XPOJXxS0Qptzu4vfF9h7kTKYWSrVesOU3QKYbjEAf95 NewF9FhAlYqYrwIwnuAZ8TdXVDYt7Z3z506//sf6zoRwYIDA8RDqFGRuPMXUsoUnf/KKPrtR ceLcSUP/JCNiYbf1/QtW8S6Ca/4qJFXQHp0knqJPGmwuFHsarSdpvZQ9qpxD3FnuPyo64S2N Dfq8TAeifNp2pAmPY2PAHQ3nOmKgMG8Gn5QiORvMUGzSz8Lo31LW58NdBKbh6bci5+t/HE0H pnyVf5xhNC/FuQINBFl4pQoBEACr+MgxWHUP76oNNYjRiNDhaIVtnPRqxiZ9v4H5FPxJy9UD Bqr54rifr1E+K+yYNPt/Po43vVL2cAyfyI/LVLlhiY4yH6T1n+Di/hSkkviCaf13gczuvgz4 KVYLwojU8+naJUsiCJw01MjO3pg9GQ+47HgsnRjCdNmmHiUQqksMIfd8k3reO9SUNlEmDDNB XuSzkHjE5y/R/6p8uXaVpiKPfHoULjNRWaFc3d2JGmxJpBdpYnajoz61m7XJlgwl/B5Ql/6B dHGaX3VHxOZsfRfugwYF9CkrPbyO5PK7yJ5vaiWre7aQ9bmCtXAomvF1q3/qRwZp77k6i9R3 tWfXjZDOQokw0u6d6DYJ0Vkfcwheg2i/Mf/epQl7Pf846G3PgSnyVK6cRwerBl5a68w7xqVU 4KgAh0DePjtDcbcXsKRT9D63cfyfrNE+ea4i0SVik6+N4nAj1HbzWHTk2KIxTsJXypibOKFX 2VykltxutR1sUfZBYMkfU4PogE7NjVEU7KtuCOSAkYzIWrZNEQrxYkxHLJsWruhSYNRsqVBy KvY6JAsq/i5yhVd5JKKU8wIOgSwC9P6mXYRgwPyfg15GZpnw+Fpey4bCDkT5fMOaCcS+vSU1 UaFmC4Ogzpe2BW2DOaPU5Ik99zUFNn6cRmOOXArrryjFlLT5oSOe4IposgWzdwARAQABiQIl BBgBCAAPBQJZeKUKAhsMBQkJZgGAAAoJEKOGQNwGMqM5ELoP/jj9d9gF1Al4+9bngUlYohYu 0sxyZo9IZ7Yb7cHuJzOMqfgoP4tydP4QCuyd9Q2OHHL5AL4VFNb8SvqAxxYSPuDJTI3JZwI7 d8JTPKwpulMSUaJE8ZH9n8A/+sdC3CAD4QafVBcCcbFe1jifHmQRdDrvHV9Es14QVAOTZhnJ vweENyHEIxkpLsyUUDuVypIo6y/Cws+EBCWt27BJi9GH/EOTB0wb+2ghCs/i3h8a+bi+bS7L FCCm/AxIqxRurh2UySn0P/2+2eZvneJ1/uTgfxnjeSlwQJ1BWzMAdAHQO1/lnbyZgEZEtUZJ x9d9ASekTtJjBMKJXAw7GbB2dAA/QmbA+Q+Xuamzm/1imigz6L6sOt2n/X/SSc33w8RJUyor SvAIoG/zU2Y76pKTgbpQqMDmkmNYFMLcAukpvC4ki3Sf086TdMgkjqtnpTkEElMSFJC8npXv 3QnGGOIfFug/qs8z03DLPBz9VYS26jiiN7QIJVpeeEdN/LKnaz5LO+h5kNAyj44qdF2T2AiF HxnZnxO5JNP5uISQH3FjxxGxJkdJ8jKzZV7aT37sC+Rp0o3KNc+GXTR+GSVq87Xfuhx0LRST NK9ZhT0+qkiN7npFLtNtbzwqaqceq3XhafmCiw8xrtzCnlB/C4SiBr/93Ip4kihXJ0EuHSLn VujM7c/b4pps Organization: Red Hat Inc, Message-ID: <58c040b7-ac4a-1d8e-3cd6-7d3aeb6ba4f1@redhat.com> Date: Wed, 6 Nov 2019 10:57:05 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <20191106144326.GA16249@linux.intel.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Mimecast-Spam-Score: 0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="iR0hOeQ36LDK9x8KBMJOlrp4IugMqitvk" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --iR0hOeQ36LDK9x8KBMJOlrp4IugMqitvk Content-Type: multipart/mixed; boundary="ty28LAXe3TVfuOL18dtbmg3cPBr1cDIKB"; protected-headers="v1" From: Nitesh Narayan Lal To: Sean Christopherson Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, pbonzini@redhat.com, mtosatti@redhat.com, rkrcmar@redhat.com, vkuznets@redhat.com, wanpengli@tencent.com, jmattson@google.com, joro@8bytes.org Message-ID: <58c040b7-ac4a-1d8e-3cd6-7d3aeb6ba4f1@redhat.com> Subject: Re: [Patch v1 1/2] KVM: remember position in kvm->vcpus array References: <1573047398-7665-1-git-send-email-nitesh@redhat.com> <1573047398-7665-2-git-send-email-nitesh@redhat.com> <20191106144326.GA16249@linux.intel.com> In-Reply-To: <20191106144326.GA16249@linux.intel.com> --ty28LAXe3TVfuOL18dtbmg3cPBr1cDIKB Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Content-Language: en-US On 11/6/19 9:43 AM, Sean Christopherson wrote: > On Wed, Nov 06, 2019 at 08:36:37AM -0500, Nitesh Narayan Lal wrote: >> From: Radim Kr=C4=8Dm=C3=A1=C5=99 >> >> Fetching an index for any vcpu in kvm->vcpus array by traversing >> the entire array everytime is costly. >> This patch remembers the position of each vcpu in kvm->vcpus array >> by storing it in vcpus_idx under kvm_vcpu structure. >> >> Signed-off-by: Radim Kr=C4=8Dm=C3=A1=C5=99 >> Signed-off-by: Nitesh Narayan Lal >> --- >> include/linux/kvm_host.h | 11 +++-------- >> virt/kvm/kvm_main.c | 5 ++++- >> 2 files changed, 7 insertions(+), 9 deletions(-) >> >> diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h >> index 719fc3e..31c4fde 100644 >> --- a/include/linux/kvm_host.h >> +++ b/include/linux/kvm_host.h >> @@ -266,7 +266,8 @@ struct kvm_vcpu { >> =09struct preempt_notifier preempt_notifier; >> #endif >> =09int cpu; >> -=09int vcpu_id; >> +=09int vcpu_id; /* id given by userspace at creation */ >> +=09int vcpus_idx; /* index in kvm->vcpus array */ > I'd probably prefer vcpu_idx or vcpu_index, but it's not a strong > preference by any means. Sure, I will probably replace it with vcpu_idx. > >> =09int srcu_idx; >> =09int mode; >> =09u64 requests; >> @@ -571,13 +572,7 @@ static inline struct kvm_vcpu *kvm_get_vcpu_by_id(s= truct kvm *kvm, int id) >> =20 >> static inline int kvm_vcpu_get_idx(struct kvm_vcpu *vcpu) >> { >> -=09struct kvm_vcpu *tmp; >> -=09int idx; >> - >> -=09kvm_for_each_vcpu(idx, tmp, vcpu->kvm) >> -=09=09if (tmp =3D=3D vcpu) >> -=09=09=09return idx; >> -=09BUG(); >> +=09return vcpu->vcpus_idx; >> } >> =20 >> #define kvm_for_each_memslot(memslot, slots)=09\ >> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c >> index 67ef3f2..24ab711 100644 >> --- a/virt/kvm/kvm_main.c >> +++ b/virt/kvm/kvm_main.c >> @@ -2673,7 +2673,10 @@ static int kvm_vm_ioctl_create_vcpu(struct kvm *k= vm, u32 id) >> =09=09goto unlock_vcpu_destroy; >> =09} >> =20 >> -=09BUG_ON(kvm->vcpus[atomic_read(&kvm->online_vcpus)]); >> +=09vcpu->vcpus_idx =3D atomic_read(&kvm->online_vcpus); >> + > Nit: I'd omit this newline since the assignment and BUG_ON() are directly > related. Makes sense to me. > >> +=09BUG_ON(kvm->vcpus[vcpu->vcpus_idx]); > The assignment to kvm->vcpus a few lines below should be updated to use > the new index. Ah yes. Thanks for pointing this out. > >> + >> =20 >> =09/* Now it's all set up, let userspace reach it */ >> =09kvm_get_kvm(kvm); >> --=20 >> 1.8.3.1 >> --=20 Nitesh --ty28LAXe3TVfuOL18dtbmg3cPBr1cDIKB-- --iR0hOeQ36LDK9x8KBMJOlrp4IugMqitvk Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAEBCAAdFiEEkXcoRVGaqvbHPuAGo4ZA3AYyozkFAl3C7VEACgkQo4ZA3AYy oznJChAAn/49v6/9S+zOUVx2Ww8EkOcZ5HiYdrMpQC2Zyb47a6gYwNVonHdf0t2I KTTMCygGVH7x4W5gcqyEaQ9XWCpjkDxZZbVsH+y4PD+T6Jk4ykawgbk+WfWhFUCl Q3CN/59C5gUYuT025OVq7RRJTa7W4oQ1JGi+oZeQD+qK4LjhYA46SFFLAyz58wJ8 OmyRUA6Z6H027CerSEYmN7i6gpNpZGVFY7pnbe3YnQGY91+w3Vr6xlTtZD/zz4L0 mnJv+uuV6Yu6nYDdFgIMpYB7o8bP180BvxDQl4lVjvtkpV/SUIoEcOFOSqlotjFF /0b1wPeGr2gJa0U6MRo/lmRZxJgPRiYXN1YSJyXQo1RqeK8VMZ//5MDyb0ke4Wfa Ogd/9i2upKAVgXMuwscJ9/UtKo+vdARa0p2anYSDglnNqYQLEw1IYpsOGTqb5LA6 C3VnNwVjo5aoAHEfoPuDAcib8pTfNnsJ7Sm2hwkhGrnmZwxjOyp/U+MD4cbxG6v2 ntfnE8JIX9pU3D8tRnVlGtlmpGWjs4ZcWhikMl5UTPlMTzaobRua3wg2kG8PswRO ywmb9YAl8rSsyZlbgE1rnXlSFn9mcI69BFEbiyFyCK/rb9oDRj+1UDefz/qeCQPY DeJAkSesMCi8yBHYBmt1Qhtjmd6lJzlzS2jOgllhHbC7yZhZC6c= =IwmN -----END PGP SIGNATURE----- --iR0hOeQ36LDK9x8KBMJOlrp4IugMqitvk--