From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758224Ab0ERUHy (ORCPT ); Tue, 18 May 2010 16:07:54 -0400 Received: from mx1.redhat.com ([209.132.183.28]:17071 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752425Ab0ERUHw (ORCPT ); Tue, 18 May 2010 16:07:52 -0400 From: Masami Hiramatsu Subject: [PATCH -tip v2 0/5] kprobes: batch (un)optimization support To: Ingo Molnar , lkml Cc: Ananth N Mavinakayanahalli , Ingo Molnar , Jim Keniston , Jason Baron , Mathieu Desnoyers , systemtap , DLE Date: Tue, 18 May 2010 16:12:44 -0400 Message-ID: <20100518201244.6058.73083.stgit@localhost6.localdomain6> User-Agent: StGIT/0.14.3 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, Here is the 2nd version of batch optimizing patch series. Since current kprobes jump optimization calls stop_machine() for each probe, it can make a lot latency noise when (un)registering a lot of probes (~1000) at once. For example, on 4 core Xeon, 256 probes optimization takes 770us in average (max 3.3ms). This patch series introduces batch (un)optimization which modifies code with just one stop_machine(), and it improves optimization time to 90us in average (max 330us). - Introduce text_poke_smp_batch() which modifies multiple codes with one stop_machine(). - Limit how many probes can be (un)optimized at once. - Introduce delayed unoptimization for batch processing. text_poke_smp_batch() also helps Jason's Jump label to reduce its overhead coming from text_poke_smp(). Changes in v2: - Add kprobes selftest bugfix patch. - Add some comments about locks according to Mathieu's comment. - Allocate working buffers when initializing kprobes, instead of using static arraies. - Merge max optimization limit patch into batch optimizing patch. Thank you, --- Masami Hiramatsu (5): kprobes: Support delayed unoptimization kprobes/x86: Use text_poke_smp_batch x86: Introduce text_poke_smp_batch() for batch-code modifying [CLEANUP] kprobes: Remove redundant text_mutex lock in optimize [BUGFIX] kprobes: Fix selftest to clear flags field for reusing probes arch/x86/include/asm/alternative.h | 7 + arch/x86/include/asm/kprobes.h | 4 arch/x86/kernel/alternative.c | 49 +++- arch/x86/kernel/kprobes.c | 114 +++++++++ include/linux/kprobes.h | 4 kernel/kprobes.c | 442 ++++++++++++++++++++++++------------ kernel/test_kprobes.c | 12 + 7 files changed, 464 insertions(+), 168 deletions(-) -- Masami Hiramatsu e-mail: mhiramat@redhat.com