From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752277AbeBWVd7 (ORCPT ); Fri, 23 Feb 2018 16:33:59 -0500 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:51992 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751527AbeBWVd6 (ORCPT ); Fri, 23 Feb 2018 16:33:58 -0500 From: Joe Lawrence To: live-patching@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Josh Poimboeuf , Jessica Yu , Jiri Kosina , Miroslav Benes , Petr Mladek , Jason Baron , Evgenii Shatokhin Subject: [PATCH v0 3/3] livepatch: update documentation for shadow variables Date: Fri, 23 Feb 2018 16:33:50 -0500 Message-Id: <1519421630-12025-4-git-send-email-joe.lawrence@redhat.com> In-Reply-To: <1519421630-12025-1-git-send-email-joe.lawrence@redhat.com> References: <1519421630-12025-1-git-send-email-joe.lawrence@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Update livepatch shadow variable documentation with respect to new atomic replace / cumulative patch functionality. Signed-off-by: Joe Lawrence --- Documentation/livepatch/shadow-vars.txt | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+) diff --git a/Documentation/livepatch/shadow-vars.txt b/Documentation/livepatch/shadow-vars.txt index 89c66634d600..9a2754cf551c 100644 --- a/Documentation/livepatch/shadow-vars.txt +++ b/Documentation/livepatch/shadow-vars.txt @@ -179,6 +179,30 @@ doesn't matter what data value the shadow variable holds, its existence suggests how to handle the parent object. +Use in cumulative patches +------------------------- + +Cumulative livepatches provide a "one-stop" module containing all active +livepatch code. A cumulative patch disables and replaces any previously +loaded livepatch. Shadow variable lifetimes should be carefully +considered when loading cumulative livepatches: + +- If shadow variables lifetimes are specific to livepatch module + versions, it may make sense to free them when the corresponding + livepatch module is unloaded. + +- If shadow variable instances may be safely handled across cumulative + livepatch module versions, then it may make sense to free them from + unpatch callbacks. When a cumulative patch replaces an existing + livepatch, only the cumulative patch's callbacks will be executed. + This means that new cumulative livepatches may be loaded while + deprecated / disabled livepatches may be unloaded without clearing + existing shadow variables. + +See Documentation/livepatch/callbacks.txt and cumulative.txt for more +information on these subjects. + + 3. References ============= -- 1.8.3.1