Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755833AbZIVJhN (ORCPT ); Tue, 22 Sep 2009 05:37:13 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755741AbZIVJhL (ORCPT ); Tue, 22 Sep 2009 05:37:11 -0400 Received: from casper.infradead.org ([85.118.1.10]:50657 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755783AbZIVJhI (ORCPT ); Tue, 22 Sep 2009 05:37:08 -0400 Date: Tue, 22 Sep 2009 11:37:08 +0200 From: Arjan van de Ven To: Avi Kivity Cc: Ingo Molnar , "H. Peter Anvin" , linux-kernel@vger.kernel.org, kvm@vger.kernel.org, Marcelo Tosatti Subject: Re: [PATCH v2] core, x86: Add user return notifiers Message-ID: <20090922113708.65f655f6@infradead.org> In-Reply-To: <4AB8980D.5070803@redhat.com> References: <4AB3CDEC.5050902@zytor.com> <1253342422-13811-1-git-send-email-avi@redhat.com> <4AB8980D.5070803@redhat.com> Organization: Intel X-Mailer: Claws Mail 3.7.2 (GTK+ 2.14.7; i386-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 821 Lines: 25 On Tue, 22 Sep 2009 12:25:33 +0300 Avi Kivity wrote: > On 09/19/2009 09:40 AM, Avi Kivity wrote: > > Add a general per-cpu notifier that is called whenever the kernel is > > about to return to userspace. The notifier uses a thread_info flag > > and existing checks, so there is no impact on user return or context > > switch fast paths. > > > > Ingo/Peter? isn't this like really expensive when used ? -- Arjan van de Ven Intel Open Source Technology Centre For development, discussion and tips for power savings, visit http://www.lesswatts.org -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/