From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:45109) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1b0ECc-0005ik-Bi for qemu-devel@nongnu.org; Tue, 10 May 2016 16:24:23 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1b0ECY-0006Co-0S for qemu-devel@nongnu.org; Tue, 10 May 2016 16:24:21 -0400 Received: from mx1.redhat.com ([209.132.183.28]:58817) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1b0ECX-0006Ch-QV for qemu-devel@nongnu.org; Tue, 10 May 2016 16:24:17 -0400 Received: from int-mx09.intmail.prod.int.phx2.redhat.com (int-mx09.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 9B8FB85542 for ; Tue, 10 May 2016 20:24:16 +0000 (UTC) Date: Tue, 10 May 2016 17:24:14 -0300 From: Eduardo Habkost Message-ID: <20160510202414.GD4457@thinpad.lan.raisama.net> References: <1462192431-146342-1-git-send-email-imammedo@redhat.com> <1462192431-146342-13-git-send-email-imammedo@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1462192431-146342-13-git-send-email-imammedo@redhat.com> Subject: Re: [Qemu-devel] [RFC 12/42] pc: initialize legacy hotplug only for 2.6 and older machine types List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Igor Mammedov Cc: qemu-devel@nongnu.org, mst@redhat.com, marcel@redhat.com, eblake@redhat.com, armbru@redhat.com, drjones@redhat.com On Mon, May 02, 2016 at 02:33:21PM +0200, Igor Mammedov wrote: > on old machine types CPU hotplug was uncondtionally > enabled since it was introduced, consuming IO ports > and providing AML regardles of whether it was actually > in use or not. Keep it so for 2.6 and older machines. > > New machine types will have an option to turn CPU > hotplug on if it's needed while by default it stays > disabled not consuming extra RAM/IO resources. > > Signed-off-by: Igor Mammedov What if people are using "-machine pc -smp N,max_cpus=M"? Shouldn't we at least warning about missing CPU hotplug support when using just "max_cpus" with no "cpu-hotplug=on" with pc-2.7 and newer? Should max_cpus > smp_cpus automatically set cpu-hotplug=on? -- Eduardo