From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rik van Riel Subject: Re: [PATCH 1/5] rcu,nohz: add state parameter to context_tracking_user_enter/exit Date: Fri, 06 Feb 2015 22:53:34 -0500 Message-ID: <54D58C3E.50804@redhat.com> References: <1423167832-17609-1-git-send-email-riel@redhat.com> <1423167832-17609-2-git-send-email-riel@redhat.com> <20150206172209.GC21905@lerouge> <54D505E5.9000003@redhat.com> <20150206182258.GH21905@lerouge> <54D50D4C.8010505@redhat.com> <20150206231511.GA18934@lerouge> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Cc: kvm@vger.kernel.org, borntraeger@de.ibm.com, linux-kernel@vger.kernel.org, mtosatti@redhat.com, mingo@kernel.orgm, ak@linux.intel.com, oleg@redhat.com, masami.hiramatsu.pt@hitachi.com, paulmck@linux.vnet.ibm.com, lcapitulino@redhat.com, pbonzini@redhat.com To: Frederic Weisbecker Return-path: Received: from mx1.redhat.com ([209.132.183.28]:53514 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751331AbbBGDxt (ORCPT ); Fri, 6 Feb 2015 22:53:49 -0500 In-Reply-To: <20150206231511.GA18934@lerouge> Sender: kvm-owner@vger.kernel.org List-ID: -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 02/06/2015 06:15 PM, Frederic Weisbecker wrote: > Just a few things then: > > 1) In this case rename context_tracking_user_enter/exit() to > context_tracking_enter() and context_tracking_exit(), since it's > not anymore about user only but about any generic context. > > 2) We have the "WARN_ON_ONCE(!current->mm);" condition that is a > debug check specific to userspace transitions because kernel > threads aren't expected to resume to userspace. Can we also expect > that we never switch to/from guest from a kernel thread? AFAICS > this happens from an ioctl (thus user task) in x86 for kvm. But I > only know this case. > > 3) You might want to update a few comments that assume we only deal > with userspace transitions. > > 4) trace_user_enter/exit() should stay user-transitions specific. Paul, would you like me to send follow-up patches with the cleanups suggested by Frederic, or would you prefer me to send a new series with the cleanups integrated? Frederic, I will also add the cleanup you suggested for patch 4/5. - -- All rights reversed -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQEcBAEBAgAGBQJU1Yw+AAoJEM553pKExN6DhycH/ifPeaRaFcj/BBKaDf7BmKAJ cGMplf/vMtJA5DCFfZTmRp5Yb/9f3XBk8MU4Z+oWZFPB/msA8WkibhZtRGXpXXl9 7XgDXaXUuo++Axhb3SYHXEDhkPkhmfdjlctyr5ZUu3gHqkeWl6utv0t4anIBfo3Z NdWG8yEhgKU6OyFppf3CH0Cm46xPN+pUyAFMgK9HbSfDkR3a9rMZ32aQq8fyV15e LV4qE+/lPi7lyoLqbHmmU+pqp6iBqyQ9uFIDCRAoBBXF5jh0jxEynRubBn2D1HZJ FBi+dBWGhAjRN05tuurvkwbJtcmTpnsHyNrmzNlAeop0Upc/5Vta43zN/nu1AFA= =Z9mE -----END PGP SIGNATURE-----