From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753464Ab1HNPwB (ORCPT ); Sun, 14 Aug 2011 11:52:01 -0400 Received: from hera.kernel.org ([140.211.167.34]:40176 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751135Ab1HNPv7 (ORCPT ); Sun, 14 Aug 2011 11:51:59 -0400 Date: Sun, 14 Aug 2011 15:51:36 GMT From: tip-bot for Peter Zijlstra Message-ID: Cc: linux-kernel@vger.kernel.org, hpa@zytor.com, mingo@redhat.com, a.p.zijlstra@chello.nl, tglx@linutronix.de, mingo@elte.hu Reply-To: mingo@redhat.com, hpa@zytor.com, linux-kernel@vger.kernel.org, a.p.zijlstra@chello.nl, tglx@linutronix.de, mingo@elte.hu To: linux-tip-commits@vger.kernel.org Subject: [tip:perf/core] perf, x86: Avoid kfree() in CPU_STARTING Git-Commit-ID: 7fdba1ca10462f42ad2246b918fe6368f5ce488e X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.2.3 (hera.kernel.org [127.0.0.1]); Sun, 14 Aug 2011 15:51:39 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 7fdba1ca10462f42ad2246b918fe6368f5ce488e Gitweb: http://git.kernel.org/tip/7fdba1ca10462f42ad2246b918fe6368f5ce488e Author: Peter Zijlstra AuthorDate: Fri, 22 Jul 2011 13:41:54 +0200 Committer: Ingo Molnar CommitDate: Sun, 14 Aug 2011 11:53:02 +0200 perf, x86: Avoid kfree() in CPU_STARTING On -rt kfree() can schedule, but CPU_STARTING is before the CPU is fully up and running. These are contradictory, so avoid it. Instead push the kfree() to CPU_ONLINE where we're free to schedule. Reported-by: Thomas Gleixner Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/n/tip-kwd4j6ayld5thrscvaxgjquv@git.kernel.org Signed-off-by: Ingo Molnar --- arch/x86/kernel/cpu/perf_event.c | 8 ++++++++ arch/x86/kernel/cpu/perf_event_amd.c | 2 +- arch/x86/kernel/cpu/perf_event_intel.c | 2 +- 3 files changed, 10 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c index 4ee3abf..594d425 100644 --- a/arch/x86/kernel/cpu/perf_event.c +++ b/arch/x86/kernel/cpu/perf_event.c @@ -129,6 +129,8 @@ struct cpu_hw_events { * AMD specific bits */ struct amd_nb *amd_nb; + + void *kfree_on_online; }; #define __EVENT_CONSTRAINT(c, n, m, w) {\ @@ -1466,10 +1468,12 @@ static int __cpuinit x86_pmu_notifier(struct notifier_block *self, unsigned long action, void *hcpu) { unsigned int cpu = (long)hcpu; + struct cpu_hw_events *cpuc = &per_cpu(cpu_hw_events, cpu); int ret = NOTIFY_OK; switch (action & ~CPU_TASKS_FROZEN) { case CPU_UP_PREPARE: + cpuc->kfree_on_online = NULL; if (x86_pmu.cpu_prepare) ret = x86_pmu.cpu_prepare(cpu); break; @@ -1479,6 +1483,10 @@ x86_pmu_notifier(struct notifier_block *self, unsigned long action, void *hcpu) x86_pmu.cpu_starting(cpu); break; + case CPU_ONLINE: + kfree(cpuc->kfree_on_online); + break; + case CPU_DYING: if (x86_pmu.cpu_dying) x86_pmu.cpu_dying(cpu); diff --git a/arch/x86/kernel/cpu/perf_event_amd.c b/arch/x86/kernel/cpu/perf_event_amd.c index 941caa2..ee9436c 100644 --- a/arch/x86/kernel/cpu/perf_event_amd.c +++ b/arch/x86/kernel/cpu/perf_event_amd.c @@ -350,7 +350,7 @@ static void amd_pmu_cpu_starting(int cpu) continue; if (nb->nb_id == nb_id) { - kfree(cpuc->amd_nb); + cpuc->kfree_on_online = cpuc->amd_nb; cpuc->amd_nb = nb; break; } diff --git a/arch/x86/kernel/cpu/perf_event_intel.c b/arch/x86/kernel/cpu/perf_event_intel.c index f88af2c..3751494 100644 --- a/arch/x86/kernel/cpu/perf_event_intel.c +++ b/arch/x86/kernel/cpu/perf_event_intel.c @@ -1362,7 +1362,7 @@ static void intel_pmu_cpu_starting(int cpu) pc = per_cpu(cpu_hw_events, i).shared_regs; if (pc && pc->core_id == core_id) { - kfree(cpuc->shared_regs); + cpuc->kfree_on_online = cpuc->shared_regs; cpuc->shared_regs = pc; break; }