From patchwork Fri Oct 23 03:29:43 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Josh Don X-Patchwork-Id: 1386492 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming-netdev@ozlabs.org Delivered-To: patchwork-incoming-netdev@ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org (client-ip=23.128.96.18; helo=vger.kernel.org; envelope-from=netdev-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=google.com header.i=@google.com header.a=rsa-sha256 header.s=20161025 header.b=tz+FVd1p; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by ozlabs.org (Postfix) with ESMTP id 4CHV9l5wxmz9sTR for ; Fri, 23 Oct 2020 14:30:35 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S374847AbgJWDaX (ORCPT ); Thu, 22 Oct 2020 23:30:23 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40706 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S374835AbgJWDaW (ORCPT ); Thu, 22 Oct 2020 23:30:22 -0400 Received: from mail-qv1-xf49.google.com (mail-qv1-xf49.google.com [IPv6:2607:f8b0:4864:20::f49]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BFBD6C0613CF for ; Thu, 22 Oct 2020 20:30:22 -0700 (PDT) Received: by mail-qv1-xf49.google.com with SMTP id d16so115302qvy.16 for ; Thu, 22 Oct 2020 20:30:22 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=sender:date:in-reply-to:message-id:mime-version:references:subject :from:to:cc; bh=q84jJ3bGQh9hixZvKUeeIGN3DtugPKTamoF/dyrHLFI=; b=tz+FVd1pN36tw1bBQmvqr+Y2n0MIU+W7R+izbV8oJ8fgeAKPZoplKAvJcLYPYctDkN FiltZT50WLAaR4aspJVHloJjO6Yw1L1Qo2/gY707fc0byoSUHUFN4+yUOfmvLN7b7BLf dFvtLW5stbWzfFZn3avsXzwdQ5dlSZJ8ADvMW8xLX8kg/cMUonSvv0jYUXn/Y7Ax8PvG 3hAzTfDOVNGkgm+apl6pysVZC+xovU7QLo3krg1eUDk/srcG7SOLFJaiJleL6ahNbCxA DCkMacJ9RvSY6jYKBxMbCsMGmthYVsXsNzmhdmF9SZIZlLoeQ+5G6/o8OcyIVvsEkQaw U9Uw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=q84jJ3bGQh9hixZvKUeeIGN3DtugPKTamoF/dyrHLFI=; b=ItmNai/SLupHB8sfKnkHIiAK2O2TcGRhpT4gmYimn7NpceEPoHkCst0UCnr3CrOHd6 muBxmU267Fw0OIdZN2FXaqoB9yUQNmnWJ6/vQwVpwpsGC4WkchWUGR0cIl2cyhUZ2z2z G46am/LTKEI5v4e5alYVR2/zs0ViTfnMuAv0Cn6dASQBh6krTmnNsolYJKufV5epnQq2 FtcAAO1SzxhbSYA0nNj+wOo91vIQ4FH+vEmRV4h7IqwYD2LpaCJBIJV4fWDZIMebRx04 xuc2hpyhaWLOjufc/snPdF1Dz5D+Q5Wkwwj5ESMbOFmU4OgSfznGAfhKIAPvrqb0e72c IgXQ== X-Gm-Message-State: AOAM532x5IbuMnga9uZgXeR/1iaXbp7loF/4rSN+Uzty6nnK76jNLcLI 6AroVIIHizFGh/75o2M/6jeUOD+Ock2L X-Google-Smtp-Source: ABdhPJxbtFDCbtjPjdxOYTFaImtDm6yGGHc8tKKsm9bUQfUsi1wM/ldih7BglY7z7cH9xMS1lGGikQ0vDTOY Sender: "joshdon via sendgmr" X-Received: from joshdon.svl.corp.google.com ([2620:15c:2cd:202:a28c:fdff:fee1:cc86]) (user=joshdon job=sendgmr) by 2002:a05:6214:122a:: with SMTP id p10mr488108qvv.0.1603423821912; Thu, 22 Oct 2020 20:30:21 -0700 (PDT) Date: Thu, 22 Oct 2020 20:29:43 -0700 In-Reply-To: <20201023032944.399861-1-joshdon@google.com> Message-Id: <20201023032944.399861-2-joshdon@google.com> Mime-Version: 1.0 References: <20201023032944.399861-1-joshdon@google.com> X-Mailer: git-send-email 2.29.0.rc1.297.gfa9743e501-goog Subject: [PATCH 2/3] kvm: better handling for kvm halt polling From: Josh Don To: Ingo Molnar , Peter Zijlstra , Juri Lelli , Vincent Guittot , "David S. Miller" , Jakub Kicinski Cc: Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Paolo Bonzini , Eric Dumazet , linux-kernel@vger.kernel.org, netdev@vger.kernel.org, kvm@vger.kernel.org, Josh Don , Xi Wang Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Add the new functions prepare_to_busy_poll() and friends to kvm_vcpu_block. The busy polling cpu will be considered an idle target during wake up balancing. cpu_relax is also added to the polling loop to improve the performance of other hw threads sharing the busy polling core. Suggested-by: Xi Wang Signed-off-by: Josh Don Signed-off-by: Xi Wang --- virt/kvm/kvm_main.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index cf88233b819a..8f818f0fc979 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -2772,7 +2772,9 @@ void kvm_vcpu_block(struct kvm_vcpu *vcpu) ktime_t stop = ktime_add_ns(ktime_get(), vcpu->halt_poll_ns); ++vcpu->stat.halt_attempted_poll; + prepare_to_busy_poll(); /* also disables preemption */ do { + cpu_relax(); /* * This sets KVM_REQ_UNHALT if an interrupt * arrives. @@ -2781,10 +2783,12 @@ void kvm_vcpu_block(struct kvm_vcpu *vcpu) ++vcpu->stat.halt_successful_poll; if (!vcpu_valid_wakeup(vcpu)) ++vcpu->stat.halt_poll_invalid; + end_busy_poll(false); goto out; } poll_end = cur = ktime_get(); - } while (single_task_running() && ktime_before(cur, stop)); + } while (continue_busy_poll() && ktime_before(cur, stop)); + end_busy_poll(false); } prepare_to_rcuwait(&vcpu->wait);