From patchwork Sat Sep 25 00:55:17 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sean Christopherson X-Patchwork-Id: 12517113 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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A5E39C433F5 for ; Sat, 25 Sep 2021 00:55:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8D496610EA for ; Sat, 25 Sep 2021 00:55:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1346257AbhIYA5N (ORCPT ); Fri, 24 Sep 2021 20:57:13 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40288 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1346178AbhIYA5M (ORCPT ); Fri, 24 Sep 2021 20:57:12 -0400 Received: from mail-qt1-x84a.google.com (mail-qt1-x84a.google.com [IPv6:2607:f8b0:4864:20::84a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 30210C061613 for ; Fri, 24 Sep 2021 17:55:38 -0700 (PDT) Received: by mail-qt1-x84a.google.com with SMTP id l22-20020ac87b36000000b002a6c575f419so27754982qtu.23 for ; Fri, 24 Sep 2021 17:55:38 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=reply-to:date:in-reply-to:message-id:mime-version:references :subject:from:to:cc; bh=1tsfKS32dF2lOop6Q8UszZBRwEC1JoDP5uy22kEXik0=; b=tJRFGMXxcfK7pjn1+YX8rDDAthpdiwDmAlAoR2O4LLVHkl7MoFkfnuCmTDY6MHO1AC aU5DlddWuaqvJAQ2CEADWDeGHvUIp0FI39I8iy3P4amF9cNUWQNgM57HmTykWDcy+8dY Mvu71xxPYDUZ2+A3pWrg86E9wAuN+QDmT67xFTEgcecgyMJgcjVmXEjzTnAcaMkNUYaw /ZRnegcxQxaUe1Qca+BGV3DDCVscs5r4gu+tlHzecUaMdV03kKXd/csNW6uPtiB/uByL 0CzeZSzGROfkTu8PuYQOHZZQRRU/J1vbhU3wMhBJTHe4WQm7fS0zEQ9aK+6AU0nSmeBC 32Sg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:reply-to:date:in-reply-to:message-id :mime-version:references:subject:from:to:cc; bh=1tsfKS32dF2lOop6Q8UszZBRwEC1JoDP5uy22kEXik0=; b=nrTlGjiLkz6MSsgCvTH2uqO1NEmRM/REyZpdOiqmx6rhuIulYBB9AiRV7jJuCI0pKc qACKuamvpVFt0hCHwIvOyEwvZDQU16ZGoqH98qnSI0ugYqvkXhitJAFxkOv58yiZDETa v1xS65AYOl4sbYMpEokIR2eBbMX5hTfsaeYRNvihsNf+BTNSmWx7etzz8n2sUlDlUug7 2cxiS1vaQ2IVTvR5dssmWYfw4OOuyykv0h512Xd+qAZ2ZmLxDxyUTNc5mcxNbZGQ4XGX 9A5dfYpSJ961sJpxjE3xda2ZVdlFhOmjPELGuPPbYl8m8hGSNfOGqhI5Y0Wvv4uLnswB Q33Q== X-Gm-Message-State: AOAM5320mpclKLuv4085poFFbgHvrOHW3/5gzuTP4qsblbsq/MKp7I7Z dOGpcZ1XXeLgOebnewwvew6WA2L40uY= X-Google-Smtp-Source: ABdhPJwPQKNSl/89/W6mMga+Zk98xyYbngE63RzqoPcRph2DGAKR41ssH/CZTrknnPOD67N3xW0Inpq3BFE= X-Received: from seanjc798194.pdx.corp.google.com ([2620:15c:90:200:4c72:89be:dba3:2bcb]) (user=seanjc job=sendgmr) by 2002:a05:6214:1593:: with SMTP id m19mr13005135qvw.36.1632531337323; Fri, 24 Sep 2021 17:55:37 -0700 (PDT) Reply-To: Sean Christopherson Date: Fri, 24 Sep 2021 17:55:17 -0700 In-Reply-To: <20210925005528.1145584-1-seanjc@google.com> Message-Id: <20210925005528.1145584-4-seanjc@google.com> Mime-Version: 1.0 References: <20210925005528.1145584-1-seanjc@google.com> X-Mailer: git-send-email 2.33.0.685.g46640cef36-goog Subject: [PATCH 03/14] KVM: Refactor and document halt-polling stats update helper From: Sean Christopherson To: Marc Zyngier , Huacai Chen , Aleksandar Markovic , Paul Mackerras , Christian Borntraeger , Janosch Frank , Paolo Bonzini Cc: James Morse , Alexandru Elisei , Suzuki K Poulose , David Hildenbrand , Cornelia Huck , Claudio Imbrenda , Sean Christopherson , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, linux-mips@vger.kernel.org, kvm@vger.kernel.org, kvm-ppc@vger.kernel.org, linux-kernel@vger.kernel.org, David Matlack , Jing Zhang Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org Add a comment to document that halt-polling is considered successful even if the polling loop itself didn't detect a wake event, i.e. if a wake event was detect in the final kvm_vcpu_check_block(). Invert the param to the update helper so that the helper is a dumb function that is "told" whether or not polling was successful, as opposed to having it determinine success/failure based on blocking behavior. Opportunistically tweak the params to the update helper to reduce the line length for the call site so that it fits on a single line, and so that the prototype conforms to the more traditional kernel style. No functional change intended. Signed-off-by: Sean Christopherson Reviewed-by: David Matlack --- virt/kvm/kvm_main.c | 20 +++++++++++++------- 1 file changed, 13 insertions(+), 7 deletions(-) diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 8b33f5045b4d..12fe91a0a4c8 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -3199,13 +3199,15 @@ static int kvm_vcpu_check_block(struct kvm_vcpu *vcpu) return ret; } -static inline void -update_halt_poll_stats(struct kvm_vcpu *vcpu, u64 poll_ns, bool waited) +static inline void update_halt_poll_stats(struct kvm_vcpu *vcpu, ktime_t start, + ktime_t end, bool success) { - if (waited) - vcpu->stat.generic.halt_poll_fail_ns += poll_ns; - else + u64 poll_ns = ktime_to_ns(ktime_sub(end, start)); + + if (success) vcpu->stat.generic.halt_poll_success_ns += poll_ns; + else + vcpu->stat.generic.halt_poll_fail_ns += poll_ns; } /* @@ -3274,9 +3276,13 @@ void kvm_vcpu_block(struct kvm_vcpu *vcpu) kvm_arch_vcpu_unblocking(vcpu); block_ns = ktime_to_ns(cur) - ktime_to_ns(start); + /* + * Note, halt-polling is considered successful so long as the vCPU was + * never actually scheduled out, i.e. even if the wake event arrived + * after of the halt-polling loop itself, but before the full wait. + */ if (do_halt_poll) - update_halt_poll_stats( - vcpu, ktime_to_ns(ktime_sub(poll_end, start)), waited); + update_halt_poll_stats(vcpu, start, poll_end, !waited); if (halt_poll_allowed) { if (!vcpu_valid_wakeup(vcpu)) {