Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932711AbcDJTW1 (ORCPT ); Sun, 10 Apr 2016 15:22:27 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:55034 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933418AbcDJTTj (ORCPT ); Sun, 10 Apr 2016 15:19:39 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Arnaldo Carvalho de Melo , Jiri Olsa , "Peter Zijlstra (Intel)" , Andi Kleen , Alexander Shishkin , Jiri Olsa , Kan Liang , Linus Torvalds , Stephane Eranian , Thomas Gleixner , Vince Weaver , Wang Nan , Ingo Molnar Subject: [PATCH 3.14 75/76] perf/x86/intel: Use PAGE_SIZE for PEBS buffer size on Core2 Date: Sun, 10 Apr 2016 11:37:23 -0700 Message-Id: <20160410183518.804821365@linuxfoundation.org> X-Mailer: git-send-email 2.8.0 In-Reply-To: <20160410183516.090999097@linuxfoundation.org> References: <20160410183516.090999097@linuxfoundation.org> User-Agent: quilt/0.64 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3491 Lines: 97 3.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jiri Olsa commit 3135a66b768c5ee84c8a98b21d0330dc1c1234b4 upstream. Using PAGE_SIZE buffers makes the WRMSR to PERF_GLOBAL_CTRL in intel_pmu_enable_all() mysteriously hang on Core2. As a workaround, we don't do this. The hard lockup is easily triggered by running 'perf test attr' repeatedly. Most of the time it gets stuck on sample session with small periods. # perf test attr -vv 14: struct perf_event_attr setup : --- start --- ... 'PERF_TEST_ATTR=/tmp/tmpuEKz3B /usr/bin/perf record -o /tmp/tmpuEKz3B/perf.data -c 123 kill >/dev/null 2>&1' ret 1 Reported-by: Arnaldo Carvalho de Melo Signed-off-by: Jiri Olsa Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Andi Kleen Cc: Alexander Shishkin Cc: Jiri Olsa Cc: Kan Liang Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Stephane Eranian Cc: Thomas Gleixner Cc: Vince Weaver Cc: Wang Nan Link: http://lkml.kernel.org/r/20160301190352.GA8355@krava.redhat.com Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman --- arch/x86/kernel/cpu/perf_event.h | 1 + arch/x86/kernel/cpu/perf_event_intel_ds.c | 13 +++++++++++-- 2 files changed, 12 insertions(+), 2 deletions(-) --- a/arch/x86/kernel/cpu/perf_event.h +++ b/arch/x86/kernel/cpu/perf_event.h @@ -445,6 +445,7 @@ struct x86_pmu { pebs_active :1, pebs_broken :1; int pebs_record_size; + int pebs_buffer_size; void (*drain_pebs)(struct pt_regs *regs); struct event_constraint *pebs_constraints; void (*pebs_aliases)(struct perf_event *event); --- a/arch/x86/kernel/cpu/perf_event_intel_ds.c +++ b/arch/x86/kernel/cpu/perf_event_intel_ds.c @@ -241,7 +241,7 @@ static int alloc_pebs_buffer(int cpu) if (!x86_pmu.pebs) return 0; - buffer = kzalloc_node(PEBS_BUFFER_SIZE, GFP_KERNEL, node); + buffer = kzalloc_node(x86_pmu.pebs_buffer_size, GFP_KERNEL, node); if (unlikely(!buffer)) return -ENOMEM; @@ -258,7 +258,7 @@ static int alloc_pebs_buffer(int cpu) per_cpu(insn_buffer, cpu) = ibuffer; } - max = PEBS_BUFFER_SIZE / x86_pmu.pebs_record_size; + max = x86_pmu.pebs_buffer_size / x86_pmu.pebs_record_size; ds->pebs_buffer_base = (u64)(unsigned long)buffer; ds->pebs_index = ds->pebs_buffer_base; @@ -1047,6 +1047,7 @@ void intel_ds_init(void) x86_pmu.bts = boot_cpu_has(X86_FEATURE_BTS); x86_pmu.pebs = boot_cpu_has(X86_FEATURE_PEBS); + x86_pmu.pebs_buffer_size = PEBS_BUFFER_SIZE; if (x86_pmu.pebs) { char pebs_type = x86_pmu.intel_cap.pebs_trap ? '+' : '-'; int format = x86_pmu.intel_cap.pebs_format; @@ -1055,6 +1056,14 @@ void intel_ds_init(void) case 0: printk(KERN_CONT "PEBS fmt0%c, ", pebs_type); x86_pmu.pebs_record_size = sizeof(struct pebs_record_core); + /* + * Using >PAGE_SIZE buffers makes the WRMSR to + * PERF_GLOBAL_CTRL in intel_pmu_enable_all() + * mysteriously hang on Core2. + * + * As a workaround, we don't do this. + */ + x86_pmu.pebs_buffer_size = PAGE_SIZE; x86_pmu.drain_pebs = intel_pmu_drain_pebs_core; break;