From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758050Ab1I2X0t (ORCPT ); Thu, 29 Sep 2011 19:26:49 -0400 Received: from claw.goop.org ([74.207.240.146]:43158 "EHLO claw.goop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752734Ab1I2X0s (ORCPT ); Thu, 29 Sep 2011 19:26:48 -0400 From: Jeremy Fitzhardinge To: Steven Rostedt Cc: "David S. Miller" , David Daney , Michael Ellerman , Jan Glauber , Jason Baron , the arch/x86 maintainers , Xen Devel , Linux Kernel Mailing List , Jeremy Fitzhardinge Subject: [PATCH RFC 0/8] jump-label: allow early jump_label_enable() Date: Thu, 29 Sep 2011 16:26:30 -0700 Message-Id: X-Mailer: git-send-email 1.7.6.2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Jeremy Fitzhardinge Hi all, While trying to use the jump-label stuff for my PV ticketlock changes, I had some problems using jump labels early in the kernel's lifetime (pre-SMP). The basic problem is that even if I enable a jump_label_key, the jump_label_init() initializer ends up nopping out all the code sites. This series enables early use of jump labels by making jump_label_init() respect already-enabled keys. To do this, I've dropped arch_jump_label_poke_text_early() and replaced it with arch_jump_label_transform_early(), which is the same as the non-_early variant except that it expects to be operating in a pre-SMP environment. I've tested this on x86, but all the other architecture changes are completely untested (not even breathed on by a compiler). One big question which arises is whether the _early() function is necessary at all. All the stop_machine/mutex/etc stuff that arch_jump_label_transform() ends up doing is redundant pre-SMP, but it shouldn't hurt. Maybe we can just drop the _early function? It works on x86, at least, because jump_label_enable() works, which uses the full form. And dropping it would reduce this to a very much smaller series. Thanks, J Jeremy Fitzhardinge (8): jump_label: use proper atomic_t initializer jump_label: if a key has already been initialized, don't nop it out x86/jump_label: add arch_jump_label_transform_early() sparc/jump_label: add arch_jump_label_transform_early() mips/jump_label: add arch_jump_label_transform_early() powerpc/jump_label: add arch_jump_label_transform_early() s390/jump-label: add arch_jump_label_transform_early() jump_label: drop default arch_jump_label_transform_early arch/mips/kernel/jump_label.c | 21 +++++++++++++--- arch/powerpc/kernel/jump_label.c | 6 ++++ arch/s390/kernel/jump_label.c | 49 +++++++++++++++++++++++-------------- arch/sparc/kernel/jump_label.c | 24 +++++++++++------- arch/x86/kernel/jump_label.c | 20 +++++++++++---- include/linux/jump_label.h | 7 +++-- kernel/jump_label.c | 20 ++++++--------- 7 files changed, 94 insertions(+), 53 deletions(-) -- 1.7.6.2