From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758701AbZEDRfh (ORCPT ); Mon, 4 May 2009 13:35:37 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1758577AbZEDRep (ORCPT ); Mon, 4 May 2009 13:34:45 -0400 Received: from hera.kernel.org ([140.211.167.34]:54714 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758578AbZEDRen (ORCPT ); Mon, 4 May 2009 13:34:43 -0400 Date: Mon, 4 May 2009 17:34:06 GMT From: tip-bot for Ingo Molnar To: linux-tip-commits@vger.kernel.org Cc: linux-kernel@vger.kernel.org, hpa@zytor.com, mingo@redhat.com, tglx@linutronix.de, mingo@elte.hu Reply-To: mingo@redhat.com, hpa@zytor.com, linux-kernel@vger.kernel.org, tglx@linutronix.de, mingo@elte.hu In-Reply-To: References: Subject: [tip:perfcounters/core] perf_counter: convert perf_resource_mutex to a spinlock Message-ID: Git-Commit-ID: 1dce8d99b85aba6eddb8b8260baea944922e6fe7 X-Mailer: tip-git-log-daemon MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.0 (hera.kernel.org [127.0.0.1]); Mon, 04 May 2009 17:34:08 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 1dce8d99b85aba6eddb8b8260baea944922e6fe7 Gitweb: http://git.kernel.org/tip/1dce8d99b85aba6eddb8b8260baea944922e6fe7 Author: Ingo Molnar AuthorDate: Mon, 4 May 2009 19:23:18 +0200 Committer: Ingo Molnar CommitDate: Mon, 4 May 2009 19:30:42 +0200 perf_counter: convert perf_resource_mutex to a spinlock Now percpu counters can be initialized very early. But the init sequence uses mutex_lock(). Fortunately, perf_resource_mutex should be a spinlock anyway, so convert it. [ Impact: fix crash due to early init mutex use ] LKML-Reference: Signed-off-by: Ingo Molnar --- kernel/perf_counter.c | 16 ++++++++-------- 1 files changed, 8 insertions(+), 8 deletions(-) diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c index fcdafa2..5f86a11 100644 --- a/kernel/perf_counter.c +++ b/kernel/perf_counter.c @@ -46,9 +46,9 @@ static atomic_t nr_comm_tracking __read_mostly; int sysctl_perf_counter_priv __read_mostly; /* do we need to be privileged */ /* - * Mutex for (sysadmin-configurable) counter reservations: + * Lock for (sysadmin-configurable) counter reservations: */ -static DEFINE_MUTEX(perf_resource_mutex); +static DEFINE_SPINLOCK(perf_resource_lock); /* * Architecture provided APIs - weak aliases: @@ -3207,9 +3207,9 @@ static void __cpuinit perf_counter_init_cpu(int cpu) cpuctx = &per_cpu(perf_cpu_context, cpu); __perf_counter_init_context(&cpuctx->ctx, NULL); - mutex_lock(&perf_resource_mutex); + spin_lock(&perf_resource_lock); cpuctx->max_pertask = perf_max_counters - perf_reserved_percpu; - mutex_unlock(&perf_resource_mutex); + spin_unlock(&perf_resource_lock); hw_perf_counter_setup(cpu); } @@ -3292,7 +3292,7 @@ perf_set_reserve_percpu(struct sysdev_class *class, if (val > perf_max_counters) return -EINVAL; - mutex_lock(&perf_resource_mutex); + spin_lock(&perf_resource_lock); perf_reserved_percpu = val; for_each_online_cpu(cpu) { cpuctx = &per_cpu(perf_cpu_context, cpu); @@ -3302,7 +3302,7 @@ perf_set_reserve_percpu(struct sysdev_class *class, cpuctx->max_pertask = mpt; spin_unlock_irq(&cpuctx->ctx.lock); } - mutex_unlock(&perf_resource_mutex); + spin_unlock(&perf_resource_lock); return count; } @@ -3324,9 +3324,9 @@ perf_set_overcommit(struct sysdev_class *class, const char *buf, size_t count) if (val > 1) return -EINVAL; - mutex_lock(&perf_resource_mutex); + spin_lock(&perf_resource_lock); perf_overcommit = val; - mutex_unlock(&perf_resource_mutex); + spin_unlock(&perf_resource_lock); return count; }