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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,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 3BAFDC55181 for ; Mon, 20 Apr 2020 21:53:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1F9E720724 for ; Mon, 20 Apr 2020 21:53:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726432AbgDTVxp (ORCPT ); Mon, 20 Apr 2020 17:53:45 -0400 Received: from mx2.suse.de ([195.135.220.15]:36894 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725989AbgDTVxp (ORCPT ); Mon, 20 Apr 2020 17:53:45 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 0EE2CAE47; Mon, 20 Apr 2020 21:53:41 +0000 (UTC) Date: Mon, 20 Apr 2020 14:50:14 -0700 From: Davidlohr Bueso To: Paolo Bonzini Cc: Marc Zyngier , tglx@linutronix.de, kvm@vger.kernel.org, Davidlohr Bueso , peterz@infradead.org, torvalds@linux-foundation.org, bigeasy@linutronix.de, linux-kernel@vger.kernel.org, rostedt@goodmis.org, linux-mips@vger.kernel.org, Paul Mackerras , joel@joelfernandes.org, will@kernel.org, kvmarm@lists.cs.columbia.edu Subject: Re: [PATCH v2] kvm: Replace vcpu->swait with rcuwait Message-ID: <20200420215014.sarodevmhphnkkn7@linux-p48b> References: <20200324044453.15733-1-dave@stgolabs.net> <20200324044453.15733-4-dave@stgolabs.net> <20200420164132.tjzk5ebx35m66yce@linux-p48b> <418acdb5001a9ae836095b7187338085@misterjones.org> <20200420205641.6sgsllj6pmsnwrvp@linux-p48b> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: User-Agent: NeoMutt/20180716 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 20 Apr 2020, Paolo Bonzini wrote: >On 20/04/20 22:56, Davidlohr Bueso wrote: >> On Mon, 20 Apr 2020, Marc Zyngier wrote: >> >>> This looks like a change in the semantics of the tracepoint. Before this >>> change, 'waited' would have been true if the vcpu waited at all. Here, >>> you'd >>> have false if it has been interrupted by a signal, even if the vcpu >>> has waited >>> for a period of time. >> >> Hmm but sleeps are now uninterruptible as we're using TASK_IDLE. > >Hold on, does that mean that you can't anymore send a signal in order to >kick a thread out of KVM_RUN? Or am I just misunderstanding? Considering that the return value of the interruptible wait is not checked, I would not think this breaks KVM_RUN. Thanks, Davidlohr