From patchwork Fri Aug 14 06:49:39 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sukadev Bhattiprolu X-Patchwork-Id: 507289 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 395C7140216 for ; Fri, 14 Aug 2015 16:56:03 +1000 (AEST) Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 1E8DA1A2C87 for ; Fri, 14 Aug 2015 16:56:03 +1000 (AEST) X-Original-To: linuxppc-dev@lists.ozlabs.org Delivered-To: linuxppc-dev@lists.ozlabs.org Received: from e31.co.us.ibm.com (e31.co.us.ibm.com [32.97.110.149]) (using TLSv1 with cipher CAMELLIA256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 04AAB1A1D90 for ; Fri, 14 Aug 2015 16:51:16 +1000 (AEST) Received: from /spool/local by e31.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; Fri, 14 Aug 2015 00:51:14 -0600 X-Helo: d03dlp01.boulder.ibm.com X-MailFrom: sukadev@linux.vnet.ibm.com X-RcptTo: linuxppc-dev@lists.ozlabs.org Received: from b03cxnp08027.gho.boulder.ibm.com (b03cxnp08027.gho.boulder.ibm.com [9.17.130.19]) by d03dlp01.boulder.ibm.com (Postfix) with ESMTP id A7FC01FF004B for ; Fri, 14 Aug 2015 00:42:23 -0600 (MDT) Received: from d03av04.boulder.ibm.com (d03av04.boulder.ibm.com [9.17.195.170]) by b03cxnp08027.gho.boulder.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id t7E6pDuF44761308 for ; Thu, 13 Aug 2015 23:51:13 -0700 Received: from d03av04.boulder.ibm.com (loopback [127.0.0.1]) by d03av04.boulder.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id t7E6pDWY027303 for ; Fri, 14 Aug 2015 00:51:13 -0600 Received: from suka-t410.usor.ibm.com (suka-t410.usor.ibm.com [9.70.94.25]) by d03av04.boulder.ibm.com (8.14.4/8.14.4/NCO v10.0 AVin) with ESMTP id t7E6p91G027010; Fri, 14 Aug 2015 00:51:12 -0600 From: Sukadev Bhattiprolu To: Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Michael Ellerman Subject: [PATCH v5 6/8] perf: Add return value for perf_event_read(). Date: Thu, 13 Aug 2015 23:49:39 -0700 Message-Id: <1439534981-7937-7-git-send-email-sukadev@linux.vnet.ibm.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1439534981-7937-1-git-send-email-sukadev@linux.vnet.ibm.com> References: <1439534981-7937-1-git-send-email-sukadev@linux.vnet.ibm.com> X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 15081406-8236-0000-0000-00000E5FEC34 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: sparclinux@vger.kernel.org, linux-s390@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org MIME-Version: 1.0 Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" 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 'group' parameter is false. Signed-off-by: Sukadev Bhattiprolu --- 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 2221ebe..e3ce047 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -3177,6 +3177,7 @@ void perf_event_exec(void) struct perf_read_data { struct perf_event *event; bool group; + int ret; }; /* @@ -3217,6 +3218,7 @@ 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); @@ -3230,8 +3232,10 @@ static inline u64 perf_event_count(struct perf_event *event) return __perf_event_count(event); } -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: @@ -3240,9 +3244,11 @@ 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; @@ -3263,6 +3269,8 @@ static void perf_event_read(struct perf_event *event, bool group) update_event_times(event); raw_spin_unlock_irqrestore(&ctx->lock, flags); } + + return ret; } /* @@ -3775,7 +3783,7 @@ 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 + @@ -3784,7 +3792,7 @@ 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; @@ -3795,13 +3803,16 @@ 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 @@ -3830,6 +3841,8 @@ 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, @@ -3837,7 +3850,7 @@ 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); @@ -3854,17 +3867,27 @@ 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; } @@ -3970,7 +3993,7 @@ 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); }