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=-5.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, 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 7E74EC7618F for ; Fri, 26 Jul 2019 19:41:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5582F22BE8 for ; Fri, 26 Jul 2019 19:41:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727730AbfGZTlj (ORCPT ); Fri, 26 Jul 2019 15:41:39 -0400 Received: from mail-wr1-f66.google.com ([209.85.221.66]:33087 "EHLO mail-wr1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726103AbfGZTli (ORCPT ); Fri, 26 Jul 2019 15:41:38 -0400 Received: by mail-wr1-f66.google.com with SMTP id n9so55639517wru.0 for ; Fri, 26 Jul 2019 12:41:37 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:openpgp:message-id :date:user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=ZvWSqPjibgGXA0LoZsQsVI2IHjEaKKck/rv+AQUCjH0=; b=WE9a+7thjBGVVIkvjlaR9wZm9d4tulKAj+9wUmFyXpqYBoCalsq1D9ULxdUIYk7OVP zcWcTswSX/NUSn2j0cFd+c9u8ft15IRNnsoXuFk8ecg7fK5vdsqCG7MlvGrA2exPTlet iTk3krgylUa8Ez+gscV5JTPtGmqZHlOiWhpzgxB17mWJ1O/KftCMLh9cn7tI+xAZJjGG r9NN+mNLp/1iSzUvHxq5NaFn1x3eNRfPXoA9ik3pyRQxu/emKe78FMRD44g4fwvb/4Xq l28XsjweR3Uq5XH8HaHkQ7g5S/UflUdY6VKQgnsebgKk0F6KD3ZdL0scJ8WiaUCNBiWs gt1w== X-Gm-Message-State: APjAAAUmB/gSxpAsstS0G5EKBD41RsM912ZO+H5rcGBwIigRqiHnqDXG OqM7ZFaGBfJcBDeWfkO7+iiV8Q== X-Google-Smtp-Source: APXvYqw8D9qW7E7D7wSq1aiagwygXtodCp2APYd461jf9vywteqA6OD/zt8xAwJ/pcuBCZBVeSZPhQ== X-Received: by 2002:a5d:5692:: with SMTP id f18mr57691607wrv.104.1564170096649; Fri, 26 Jul 2019 12:41:36 -0700 (PDT) Received: from ?IPv6:2001:b07:6468:f312:cc23:f353:392:d2ee? ([2001:b07:6468:f312:cc23:f353:392:d2ee]) by smtp.gmail.com with ESMTPSA id w25sm51292326wmk.18.2019.07.26.12.41.35 (version=TLS1_3 cipher=AEAD-AES128-GCM-SHA256 bits=128/128); Fri, 26 Jul 2019 12:41:35 -0700 (PDT) Subject: Re: [patch 07/12] KVM: LAPIC: Mark hrtimer to expire in hard interrupt context To: Thomas Gleixner , LKML Cc: x86@kernel.org, Steven Rostedt , Sebastian Siewior , Anna-Maria Gleixner , Arnaldo Carvalho de Melo , Jiri Olsa , Juergen Gross References: <20190726183048.982726647@linutronix.de> <20190726185753.363363474@linutronix.de> From: Paolo Bonzini Openpgp: preference=signencrypt Message-ID: <6fea9141-1391-8466-0cf5-27f193daf5c9@redhat.com> Date: Fri, 26 Jul 2019 21:41:34 +0200 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: <20190726185753.363363474@linutronix.de> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 26/07/19 20:30, Thomas Gleixner wrote: > From: Sebastian Andrzej Siewior > > On PREEMPT_RT enabled kernels unmarked hrtimers are moved into soft > interrupt expiry mode by default. > > While that's not a functional requirement for the KVM local APIC timer > emulation, it's a latency issue which can be avoided by marking the timer > so hard interrupt context expiry is enforced. > > No functional change. > > [ tglx: Split out from larger combo patch. Add changelog. ] > > Signed-off-by: Sebastian Andrzej Siewior > Signed-off-by: Thomas Gleixner > Cc: kvm@vger.kernel.org > Cc: Paolo Bonzini > --- > arch/x86/kvm/lapic.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > --- a/arch/x86/kvm/lapic.c > +++ b/arch/x86/kvm/lapic.c > @@ -2302,7 +2302,7 @@ int kvm_create_lapic(struct kvm_vcpu *vc > apic->vcpu = vcpu; > > hrtimer_init(&apic->lapic_timer.timer, CLOCK_MONOTONIC, > - HRTIMER_MODE_ABS); > + HRTIMER_MODE_ABS_HARD); > apic->lapic_timer.timer.function = apic_timer_fn; > if (timer_advance_ns == -1) { > apic->lapic_timer.timer_advance_ns = LAPIC_TIMER_ADVANCE_ADJUST_INIT; > > Acked-by: Paolo Bonzini