From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wu Fengguang Subject: [PATCH] markers: comment usage of marker_synchronize_unregister() Date: Wed, 26 Nov 2008 20:36:52 +0800 Message-ID: <20081126123652.GA9446@localhost> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Ingo Molnar , Avi Kivity , kvm@vger.kernel.org, Lai Jiangshan , Mathieu Desnoyers , "Paul E. McKenney" , Andrew Morton , Nick Piggin To: LKML Return-path: Received: from mga14.intel.com ([143.182.124.37]:38469 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751506AbYKZMhP (ORCPT ); Wed, 26 Nov 2008 07:37:15 -0500 Content-Disposition: inline Sender: kvm-owner@vger.kernel.org List-ID: Add more comments to marker_synchronize_unregister() in order to reduce the chance of misusing. Based on comments from Lai Jiangshan . Cc: Lai Jiangshan Cc: Mathieu Desnoyers Signed-off-by: Wu Fengguang --- I'm still not sure about the last sentence. Can anyone clarify on this? Thanks! diff --git a/include/linux/marker.h b/include/linux/marker.h index 889196c..89ce1b8 100644 --- a/include/linux/marker.h +++ b/include/linux/marker.h @@ -164,6 +164,12 @@ extern void *marker_get_private_data(const char *name, marker_probe_func *probe, * marker_synchronize_unregister must be called between the last marker probe * unregistration and the end of module exit to make sure there is no caller * executing a probe when it is freed. + * + * It must be called _also_ between unregistration and destruction the data + * that unregistration-ed probes need to make sure there is no caller executing + * a probe when it's data is destroyed. + * + * It works reliably only when all probe routines do not sleep and reschedule. */ #define marker_synchronize_unregister() synchronize_sched()