From patchwork Mon May 17 14:02:40 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 440658 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=-19.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT 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 D1038C43461 for ; Mon, 17 May 2021 15:30:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B034361108 for ; Mon, 17 May 2021 15:30:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244985AbhEQPbp (ORCPT ); Mon, 17 May 2021 11:31:45 -0400 Received: from mail.kernel.org ([198.145.29.99]:56440 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244095AbhEQP3I (ORCPT ); Mon, 17 May 2021 11:29:08 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 4694861CBC; Mon, 17 May 2021 14:37:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1621262249; bh=hGFvCicMJSd+OXQXSjAVDr5lHiJ4sa10UlQ0LN+CYRk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=fLblzrjt/uvoO4nXHeWRlWltcJkx+kdFMu4U85ygofWQhKLgIXqdah1ZduSEruu7k QyeoXMsqurjgOGknlEmcCgDMbTmHCt+TXaxEvQ+ZdVhehpP08jQsh66aYWNKyFNl7E mNXgZ/z/KN2H2ftrQXYDeEoc49XqU2TmTgQS3Gc8= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Ben Segall , Venkatesh Srinivas , Paolo Bonzini , Jim Mattson Subject: [PATCH 5.11 249/329] kvm: exit halt polling on need_resched() as well Date: Mon, 17 May 2021 16:02:40 +0200 Message-Id: <20210517140310.537115832@linuxfoundation.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210517140302.043055203@linuxfoundation.org> References: <20210517140302.043055203@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Benjamin Segall commit 262de4102c7bb8e59f26a967a8ffe8cce85cc537 upstream. single_task_running() is usually more general than need_resched() but CFS_BANDWIDTH throttling will use resched_task() when there is just one task to get the task to block. This was causing long-need_resched warnings and was likely allowing VMs to overrun their quota when halt polling. Signed-off-by: Ben Segall Signed-off-by: Venkatesh Srinivas Message-Id: <20210429162233.116849-1-venkateshs@chromium.org> Signed-off-by: Paolo Bonzini Cc: stable@vger.kernel.org Reviewed-by: Jim Mattson Signed-off-by: Greg Kroah-Hartman --- virt/kvm/kvm_main.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -2814,7 +2814,8 @@ void kvm_vcpu_block(struct kvm_vcpu *vcp goto out; } poll_end = cur = ktime_get(); - } while (single_task_running() && ktime_before(cur, stop)); + } while (single_task_running() && !need_resched() && + ktime_before(cur, stop)); } prepare_to_rcuwait(&vcpu->wait);