From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755392AbbIMLNd (ORCPT ); Sun, 13 Sep 2015 07:13:33 -0400 Received: from terminus.zytor.com ([198.137.202.10]:44043 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752294AbbIMLNb (ORCPT ); Sun, 13 Sep 2015 07:13:31 -0400 Date: Sun, 13 Sep 2015 04:12:46 -0700 From: tip-bot for Sukadev Bhattiprolu Message-ID: Cc: peterz@infradead.org, linux-kernel@vger.kernel.org, tglx@linutronix.de, eranian@google.com, acme@redhat.com, sukadev@linux.vnet.ibm.com, acme@kernel.org, hpa@zytor.com, jolsa@redhat.com, torvalds@linux-foundation.org, mpe@ellerman.id.au, mingo@kernel.org, vincent.weaver@maine.edu Reply-To: linux-kernel@vger.kernel.org, tglx@linutronix.de, peterz@infradead.org, sukadev@linux.vnet.ibm.com, acme@kernel.org, acme@redhat.com, eranian@google.com, hpa@zytor.com, jolsa@redhat.com, vincent.weaver@maine.edu, mingo@kernel.org, mpe@ellerman.id.au, torvalds@linux-foundation.org In-Reply-To: <1441336073-22750-8-git-send-email-sukadev@linux.vnet.ibm.com> References: <1441336073-22750-8-git-send-email-sukadev@linux.vnet.ibm.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:perf/core] perf/core: Add return value for perf_event_read() Git-Commit-ID: 7d88962e230c8342080e7e2fe9dd5be43dc13b79 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 7d88962e230c8342080e7e2fe9dd5be43dc13b79 Gitweb: http://git.kernel.org/tip/7d88962e230c8342080e7e2fe9dd5be43dc13b79 Author: Sukadev Bhattiprolu AuthorDate: Thu, 3 Sep 2015 20:07:50 -0700 Committer: Ingo Molnar CommitDate: Sun, 13 Sep 2015 11:27:28 +0200 perf/core: Add return value for perf_event_read() When we implement the ability to read several counters at once (using the PERF_PMU_TXN_READ transaction interface), perf_event_read() can fail when the 'group' parameter is true (eg: trying to read too many events at once). For now, have perf_event_read() return an integer. Ignore the return value when the 'group' parameter is false. Signed-off-by: Sukadev Bhattiprolu Signed-off-by: Peter Zijlstra (Intel) Cc: Arnaldo Carvalho de Melo Cc: Arnaldo Carvalho de Melo Cc: Jiri Olsa Cc: Linus Torvalds Cc: Michael Ellerman Cc: Peter Zijlstra Cc: Stephane Eranian Cc: Thomas Gleixner Cc: Vince Weaver Link: http://lkml.kernel.org/r/1441336073-22750-8-git-send-email-sukadev@linux.vnet.ibm.com Signed-off-by: Ingo Molnar --- kernel/events/core.c | 45 ++++++++++++++++++++++++++++++++++----------- 1 file changed, 34 insertions(+), 11 deletions(-) diff --git a/kernel/events/core.c b/kernel/events/core.c index dd2a0b8..ade04df 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -3187,6 +3187,7 @@ void perf_event_exec(void) struct perf_read_data { struct perf_event *event; bool group; + int ret; }; /* @@ -3227,6 +3228,7 @@ static void __perf_event_read(void *info) if (sub->state == PERF_EVENT_STATE_ACTIVE) sub->pmu->read(sub); } + data->ret = 0; unlock: raw_spin_unlock(&ctx->lock); @@ -3293,8 +3295,10 @@ u64 perf_event_read_local(struct perf_event *event) return val; } -static void perf_event_read(struct perf_event *event, bool group) +static int perf_event_read(struct perf_event *event, bool group) { + int ret = 0; + /* * If event is enabled and currently active on a CPU, update the * value in the event structure: @@ -3303,9 +3307,11 @@ static void perf_event_read(struct perf_event *event, bool group) struct perf_read_data data = { .event = event, .group = group, + .ret = 0, }; smp_call_function_single(event->oncpu, __perf_event_read, &data, 1); + ret = data.ret; } else if (event->state == PERF_EVENT_STATE_INACTIVE) { struct perf_event_context *ctx = event->ctx; unsigned long flags; @@ -3326,6 +3332,8 @@ static void perf_event_read(struct perf_event *event, bool group) update_event_times(event); raw_spin_unlock_irqrestore(&ctx->lock, flags); } + + return ret; } /* @@ -3842,7 +3850,7 @@ u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running) mutex_lock(&event->child_mutex); - perf_event_read(event, false); + (void)perf_event_read(event, false); total += perf_event_count(event); *enabled += event->total_time_enabled + @@ -3851,7 +3859,7 @@ u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running) atomic64_read(&event->child_total_time_running); list_for_each_entry(child, &event->child_list, child_list) { - perf_event_read(child, false); + (void)perf_event_read(child, false); total += perf_event_count(child); *enabled += child->total_time_enabled; *running += child->total_time_running; @@ -3862,13 +3870,16 @@ u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running) } EXPORT_SYMBOL_GPL(perf_event_read_value); -static void __perf_read_group_add(struct perf_event *leader, +static int __perf_read_group_add(struct perf_event *leader, u64 read_format, u64 *values) { struct perf_event *sub; int n = 1; /* skip @nr */ + int ret; - perf_event_read(leader, true); + ret = perf_event_read(leader, true); + if (ret) + return ret; /* * Since we co-schedule groups, {enabled,running} times of siblings @@ -3897,6 +3908,8 @@ static void __perf_read_group_add(struct perf_event *leader, if (read_format & PERF_FORMAT_ID) values[n++] = primary_event_id(sub); } + + return 0; } static int perf_read_group(struct perf_event *event, @@ -3904,7 +3917,7 @@ static int perf_read_group(struct perf_event *event, { struct perf_event *leader = event->group_leader, *child; struct perf_event_context *ctx = leader->ctx; - int ret = event->read_size; + int ret; u64 *values; lockdep_assert_held(&ctx->mutex); @@ -3921,17 +3934,27 @@ static int perf_read_group(struct perf_event *event, */ mutex_lock(&leader->child_mutex); - __perf_read_group_add(leader, read_format, values); - list_for_each_entry(child, &leader->child_list, child_list) - __perf_read_group_add(child, read_format, values); + ret = __perf_read_group_add(leader, read_format, values); + if (ret) + goto unlock; + + list_for_each_entry(child, &leader->child_list, child_list) { + ret = __perf_read_group_add(child, read_format, values); + if (ret) + goto unlock; + } mutex_unlock(&leader->child_mutex); + ret = event->read_size; if (copy_to_user(buf, values, event->read_size)) ret = -EFAULT; + goto out; +unlock: + mutex_unlock(&leader->child_mutex); +out: kfree(values); - return ret; } @@ -4037,7 +4060,7 @@ static unsigned int perf_poll(struct file *file, poll_table *wait) static void _perf_event_reset(struct perf_event *event) { - perf_event_read(event, false); + (void)perf_event_read(event, false); local64_set(&event->count, 0); perf_event_update_userpage(event); }