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=-5.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 86D25C433DF for ; Mon, 17 Aug 2020 12:04:59 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 524162067C for ; Mon, 17 Aug 2020 12:04:59 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="Aw8DQ2ju" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 524162067C Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=huawei.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Date:Message-ID:From: References:To:Subject:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=NR0zseB2OeTx5egQxVb4FEJdRu2WEcmg/hNcV/iIgmk=; b=Aw8DQ2jum/aPIdvyjZaowKjiz ZeQ+n2yq6YqMf/JIqCnm6XV6PraS8/tgX9rKpQXNZHMbkoZFjLsdHh9y8/czM428rEdz/LdNR+CjL hfF7kbQIKDRu5er93LEa0qjTPXxj2SlSbIoUifuNMFQp1WZMUDXEK4OHxqm5fCGaswNEBP3GQbcce dJVO6dcx1xU3P6IwPnP6bgYB7Jx+ZN443FKgG3p3ymKGb8NPvaGIB1KDT/l3HkHWWx4eUsSGD63CX DEnHlruMw8WEW0D0hGhC1ep8R5N6O9eVzwHgvZ2DRnYtXDFrFECrdm5fo7LcfDtzrAKyvD9tvKsTp zvhH3ASOQ==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1k7drT-00017x-Vt; Mon, 17 Aug 2020 12:03:36 +0000 Received: from szxga02-in.huawei.com ([45.249.212.188] helo=huawei.com) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1k7drQ-00015v-Uy for linux-arm-kernel@lists.infradead.org; Mon, 17 Aug 2020 12:03:34 +0000 Received: from dggeme755-chm.china.huawei.com (unknown [172.30.72.55]) by Forcepoint Email with ESMTP id ADE95C4E4428103920DA; Mon, 17 Aug 2020 20:03:21 +0800 (CST) Received: from [10.174.186.8] (10.174.186.8) by dggeme755-chm.china.huawei.com (10.3.19.101) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.1913.5; Mon, 17 Aug 2020 20:03:21 +0800 Subject: Re: [RFC][PATCH 0/4] arm64:kvm: teach guest sched that VCPUs can be preempted To: Sergey Senozhatsky , "will@kernel.org" , "maz@kernel.org" References: <20200721041742.197354-1-sergey.senozhatsky@gmail.com> <20200817020310.GA1210848@jagdpanzerIV.localdomain> From: yezengruan Message-ID: Date: Mon, 17 Aug 2020 20:03:09 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:68.0) Gecko/20100101 Thunderbird/68.3.0 MIME-Version: 1.0 In-Reply-To: <20200817020310.GA1210848@jagdpanzerIV.localdomain> Content-Language: en-US X-Originating-IP: [10.174.186.8] X-ClientProxiedBy: dggeme707-chm.china.huawei.com (10.1.199.103) To dggeme755-chm.china.huawei.com (10.3.19.101) X-CFilter-Loop: Reflected X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200817_080333_253505_C86C5104 X-CRM114-Status: GOOD ( 11.48 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: joelaf@google.com, "linux-kernel@vger.kernel.org" , yezengruan@huawei.com, "Wanghaibin \(D\)" , suleiman@google.com, "kvmarm@lists.cs.columbia.edu" , "linux-arm-kernel@lists.infradead.org" Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 2020/8/17 10:03, Sergey Senozhatsky wrote: > On (20/07/21 13:17), Sergey Senozhatsky wrote: >> Hello, >> >> RFC >> >> We noticed that in a number of cases when we wake_up_process() >> on arm64 guest we end up enqueuing that task on a preempted VCPU. The culprit >> appears to be the fact that arm64 guests are not aware of VCPU preemption >> as such, so when sched picks up an idle VCPU it always assumes that VCPU >> is available: >> >> wake_up_process() >> try_to_wake_up() >> select_task_rq_fair() >> available_idle_cpu() >> vcpu_is_preempted() // return false; >> >> Which is, obviously, not the case. >> >> This RFC patch set adds a simple vcpu_is_preempted() implementation so >> that scheduler can make better decisions when it search for the idle >> (v)CPU. > Hi, > > A gentle ping. > > -ss > _______________________________________________ > kvmarm mailing list > kvmarm@lists.cs.columbia.edu > https://lists.cs.columbia.edu/mailman/listinfo/kvmarm > . Hi Sergey, I have a set of patches similar to yours. https://lore.kernel.org/lkml/20191226135833.1052-1-yezengruan@huawei.com/ _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel