From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.0 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,T_DKIMWL_WL_HIGH,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D87C1C28CC0 for ; Thu, 30 May 2019 03:09:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A8A1A24485 for ; Thu, 30 May 2019 03:09:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1559185769; bh=1E2yZP9wUD7Z28oDdb97GAXSKy+cvmrKQ+1fc9bEQUk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=Y1fSSIoTPsrY1v/BtoAU+HQics45qCE7Y8k6d5zx+Le4tvXHjmI68l2hClR0ixh1I UfzzXgf2iQLD9LA+H7FNkf820gRk4GiHvj1ox3p0I6fXhvdXRGUUcDBheGopZVU5HJ 7o5xY/UnMaTjXvIssEOP2L664738YFRe9AlUu9nE= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727571AbfE3DJ2 (ORCPT ); Wed, 29 May 2019 23:09:28 -0400 Received: from mail.kernel.org ([198.145.29.99]:44064 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727548AbfE3DJ1 (ORCPT ); Wed, 29 May 2019 23:09:27 -0400 Received: from localhost (ip67-88-213-2.z213-88-67.customer.algx.net [67.88.213.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 00B9C24476; Thu, 30 May 2019 03:09:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1559185766; bh=1E2yZP9wUD7Z28oDdb97GAXSKy+cvmrKQ+1fc9bEQUk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=XvytrlwVRJnDft2qX+E8ryFO0F3mePoUaCixzYI3BdE4/1EJGwgOKj8ws+Q5fIB17 gLfVV6pBa06+5Dvv9ciKQfwsMMZBi/KtLiSSDcFPLCKs+dY151Ag4CEDgac52wGY0/ k3XC8/xOIpGI9MmiMSd0zWrv8XRiX2iucu/D4OcE= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Tom Zanussi , "Steven Rostedt (VMware)" Subject: [PATCH 5.1 013/405] tracing: Add a check_val() check before updating cond_snapshot() track_val Date: Wed, 29 May 2019 20:00:11 -0700 Message-Id: <20190530030541.131126634@linuxfoundation.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190530030540.291644921@linuxfoundation.org> References: <20190530030540.291644921@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Tom Zanussi commit 9b2ca371b1505a547217b244f903ad3fb86fa5b4 upstream. Without this check a snapshot is taken whenever a bucket's max is hit, rather than only when the global max is hit, as it should be. Before: In this example, we do a first run of the workload (cyclictest), examine the output, note the max ('triggering value') (347), then do a second run and note the max again. In this case, the max in the second run (39) is below the max in the first run, but since we haven't cleared the histogram, the first max is still in the histogram and is higher than any other max, so it should still be the max for the snapshot. It isn't however - the value should still be 347 after the second run. # echo 'hist:keys=pid:ts0=common_timestamp.usecs if comm=="cyclictest"' >> /sys/kernel/debug/tracing/events/sched/sched_waking/trigger # echo 'hist:keys=next_pid:wakeup_lat=common_timestamp.usecs-$ts0:onmax($wakeup_lat).save(next_prio,next_comm,prev_pid,prev_prio,prev_comm):onmax($wakeup_lat).snapshot() if next_comm=="cyclictest"' >> /sys/kernel/debug/tracing/events/sched/sched_switch/trigger # cyclictest -p 80 -n -s -t 2 -D 2 # cat /sys/kernel/debug/tracing/events/sched/sched_switch/hist { next_pid: 2143 } hitcount: 199 max: 44 next_prio: 120 next_comm: cyclictest prev_pid: 0 prev_prio: 120 prev_comm: swapper/4 { next_pid: 2145 } hitcount: 1325 max: 38 next_prio: 19 next_comm: cyclictest prev_pid: 0 prev_prio: 120 prev_comm: swapper/2 { next_pid: 2144 } hitcount: 1982 max: 347 next_prio: 19 next_comm: cyclictest prev_pid: 0 prev_prio: 120 prev_comm: swapper/6 Snapshot taken (see tracing/snapshot). Details: triggering value { onmax($wakeup_lat) }: 347 triggered by event with key: { next_pid: 2144 } # cyclictest -p 80 -n -s -t 2 -D 2 # cat /sys/kernel/debug/tracing/events/sched/sched_switch/hist { next_pid: 2143 } hitcount: 199 max: 44 next_prio: 120 next_comm: cyclictest prev_pid: 0 prev_prio: 120 prev_comm: swapper/4 { next_pid: 2148 } hitcount: 199 max: 16 next_prio: 120 next_comm: cyclictest prev_pid: 0 prev_prio: 120 prev_comm: swapper/1 { next_pid: 2145 } hitcount: 1325 max: 38 next_prio: 19 next_comm: cyclictest prev_pid: 0 prev_prio: 120 prev_comm: swapper/2 { next_pid: 2150 } hitcount: 1326 max: 39 next_prio: 19 next_comm: cyclictest prev_pid: 0 prev_prio: 120 prev_comm: swapper/4 { next_pid: 2144 } hitcount: 1982 max: 347 next_prio: 19 next_comm: cyclictest prev_pid: 0 prev_prio: 120 prev_comm: swapper/6 { next_pid: 2149 } hitcount: 1983 max: 130 next_prio: 19 next_comm: cyclictest prev_pid: 0 prev_prio: 120 prev_comm: swapper/0 Snapshot taken (see tracing/snapshot). Details: triggering value { onmax($wakeup_lat) }: 39 triggered by event with key: { next_pid: 2150 } After: In this example, we do a first run of the workload (cyclictest), examine the output, note the max ('triggering value') (375), then do a second run and note the max again. In this case, the max in the second run is still 375, the highest in any bucket, as it should be. # cyclictest -p 80 -n -s -t 2 -D 2 # cat /sys/kernel/debug/tracing/events/sched/sched_switch/hist { next_pid: 2072 } hitcount: 200 max: 28 next_prio: 120 next_comm: cyclictest prev_pid: 0 prev_prio: 120 prev_comm: swapper/5 { next_pid: 2074 } hitcount: 1323 max: 375 next_prio: 19 next_comm: cyclictest prev_pid: 0 prev_prio: 120 prev_comm: swapper/2 { next_pid: 2073 } hitcount: 1980 max: 153 next_prio: 19 next_comm: cyclictest prev_pid: 0 prev_prio: 120 prev_comm: swapper/6 Snapshot taken (see tracing/snapshot). Details: triggering value { onmax($wakeup_lat) }: 375 triggered by event with key: { next_pid: 2074 } # cyclictest -p 80 -n -s -t 2 -D 2 # cat /sys/kernel/debug/tracing/events/sched/sched_switch/hist { next_pid: 2101 } hitcount: 199 max: 49 next_prio: 120 next_comm: cyclictest prev_pid: 0 prev_prio: 120 prev_comm: swapper/6 { next_pid: 2072 } hitcount: 200 max: 28 next_prio: 120 next_comm: cyclictest prev_pid: 0 prev_prio: 120 prev_comm: swapper/5 { next_pid: 2074 } hitcount: 1323 max: 375 next_prio: 19 next_comm: cyclictest prev_pid: 0 prev_prio: 120 prev_comm: swapper/2 { next_pid: 2103 } hitcount: 1325 max: 74 next_prio: 19 next_comm: cyclictest prev_pid: 0 prev_prio: 120 prev_comm: swapper/4 { next_pid: 2073 } hitcount: 1980 max: 153 next_prio: 19 next_comm: cyclictest prev_pid: 0 prev_prio: 120 prev_comm: swapper/6 { next_pid: 2102 } hitcount: 1981 max: 84 next_prio: 19 next_comm: cyclictest prev_pid: 12 prev_prio: 120 prev_comm: kworker/0:1 Snapshot taken (see tracing/snapshot). Details: triggering value { onmax($wakeup_lat) }: 375 triggered by event with key: { next_pid: 2074 } Link: http://lkml.kernel.org/r/95958351329f129c07504b4d1769c47a97b70d65.1555597045.git.tom.zanussi@linux.intel.com Cc: stable@vger.kernel.org Fixes: a3785b7eca8fd ("tracing: Add hist trigger snapshot() action") Signed-off-by: Tom Zanussi Signed-off-by: Steven Rostedt (VMware) Signed-off-by: Greg Kroah-Hartman --- kernel/trace/trace_events_hist.c | 6 ++++++ 1 file changed, 6 insertions(+) --- a/kernel/trace/trace_events_hist.c +++ b/kernel/trace/trace_events_hist.c @@ -3543,14 +3543,20 @@ static bool cond_snapshot_update(struct struct track_data *track_data = tr->cond_snapshot->cond_data; struct hist_elt_data *elt_data, *track_elt_data; struct snapshot_context *context = cond_data; + struct action_data *action; u64 track_val; if (!track_data) return false; + action = track_data->action_data; + track_val = get_track_val(track_data->hist_data, context->elt, track_data->action_data); + if (!action->track_data.check_val(track_data->track_val, track_val)) + return false; + track_data->track_val = track_val; memcpy(track_data->key, context->key, track_data->key_len);