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From: Thomas Gleixner <tglx@linutronix.de>
To: LKML <linux-kernel@vger.kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Borislav Petkov <bp@alien8.de>,
	Sebastian Siewior <bigeasy@linutronix.de>,
	Nicholas Piggin <npiggin@gmail.com>,
	Don Zickus <dzickus@redhat.com>,
	Chris Metcalf <cmetcalf@mellanox.com>,
	Ulrich Obergfell <uobergfe@redhat.com>
Subject: [patch 28/29] lockup_detector/perf: Simplify deferred event destroy
Date: Thu, 31 Aug 2017 09:16:26 +0200
Message-ID: <20170831073055.251195167@linutronix.de> (raw)
In-Reply-To: <20170831071558.995235362@linutronix.de>


[-- Attachment #0: lockup_detector-perf--Simplify-deferred-event-destroy.patch --]
[-- Type: text/plain, Size: 1393 bytes --]

Now that all functionality is properly serialized against CPU hotplug,
remove the extra per cpu storage which holds the disabled events for
cleanup. The core makes sure that cleanup happens before new events are
created.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 kernel/watchdog_hld.c |    7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

--- a/kernel/watchdog_hld.c
+++ b/kernel/watchdog_hld.c
@@ -21,7 +21,6 @@
 static DEFINE_PER_CPU(bool, hard_watchdog_warn);
 static DEFINE_PER_CPU(bool, watchdog_nmi_touch);
 static DEFINE_PER_CPU(struct perf_event *, watchdog_ev);
-static DEFINE_PER_CPU(struct perf_event *, dead_event);
 static struct cpumask dead_events_mask;
 
 static unsigned long hardlockup_allcpu_dumped;
@@ -204,8 +203,6 @@ void hardlockup_detector_perf_disable(vo
 
 	if (event) {
 		perf_event_disable(event);
-		this_cpu_write(watchdog_ev, NULL);
-		this_cpu_write(dead_event, event);
 		cpumask_set_cpu(smp_processor_id(), &dead_events_mask);
 		watchdog_cpus--;
 	}
@@ -221,9 +218,9 @@ void hardlockup_detector_perf_cleanup(vo
 	int cpu;
 
 	for_each_cpu(cpu, &dead_events_mask) {
-		struct perf_event *event = per_cpu(dead_event, cpu);
+		struct perf_event *event = per_cpu(watchdog_ev, cpu);
 
-		per_cpu(dead_event, cpu) = NULL;
+		per_cpu(watchdog_ev, cpu) = NULL;
 		perf_event_release_kernel(event);
 	}
 	cpumask_clear(&dead_events_mask);

  parent reply index

Thread overview: 47+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-08-31  7:15 [patch 00/29] lockup_detector: Cure hotplug deadlocks and replace duct tape Thomas Gleixner
2017-08-31  7:15 ` [patch 01/29] hardlockup_detector: Provide interface to stop/restart perf events Thomas Gleixner
2017-09-06 16:14   ` Borislav Petkov
2017-08-31  7:16 ` [patch 02/29] perf/x86/intel: Sanitize PMU HT bug workaround Thomas Gleixner
2017-08-31  7:16 ` [patch 03/29] lockup_detector: Provide interface to stop from poweroff() Thomas Gleixner
2017-08-31  7:16 ` [patch 04/29] parisc: Use lockup_detector_stop() Thomas Gleixner
2017-08-31  7:16 ` [patch 05/29] lockup_detector: Remove broken suspend/resume interfaces Thomas Gleixner
2017-08-31  7:16 ` [patch 06/29] lockup_detector: Rework cpu hotplug locking Thomas Gleixner
2017-08-31  7:16 ` [patch 07/29] lockup_detector: Rename watchdog_proc_mutex Thomas Gleixner
2017-08-31  7:16 ` [patch 08/29] lockup_detector: Mark hardlockup_detector_disable() __init Thomas Gleixner
2017-08-31  7:16 ` [patch 09/29] lockup_detector/perf: Remove broken self disable on failure Thomas Gleixner
2017-08-31  7:16 ` [patch 10/29] lockup_detector/perf: Prevent cpu hotplug deadlock Thomas Gleixner
2017-09-01 19:02   ` Don Zickus
2017-09-01 19:29     ` Thomas Gleixner
2017-09-05 14:51       ` Don Zickus
2017-08-31  7:16 ` [patch 11/29] lockup_detector: Remove park_in_progress hackery Thomas Gleixner
     [not found]   ` <CAEeg4=CJohPTi8FUNWqb3egsbZnExyJapcNC7wD-2amXTsMrYw@mail.gmail.com>
2017-09-04 12:10     ` Peter Zijlstra
2017-09-05 15:15       ` Don Zickus
2017-09-05 15:42         ` Thomas Gleixner
2017-09-05 13:58     ` Thomas Gleixner
2017-09-05 19:19       ` [patch V2 11/29] lockup_detector: Remove park_in_progress obfuscation Thomas Gleixner
2017-09-14 10:43         ` [tip:core/urgent] watchdog/core: Remove the " tip-bot for Thomas Gleixner
2017-08-31  7:16 ` [patch 12/29] lockup_detector: Cleanup stub functions Thomas Gleixner
2017-08-31  7:16 ` [patch 13/29] lockup_detector: Cleanup the ifdef maze Thomas Gleixner
2017-08-31  7:16 ` [patch 14/29] lockup_detector: Split out cpumask write function Thomas Gleixner
2017-08-31  7:16 ` [patch 15/29] smpboot/threads: Avoid runtime allocation Thomas Gleixner
2017-08-31  7:16 ` [patch 16/29] lockup_detector: Create new thread handling infrastructure Thomas Gleixner
2017-08-31  7:16 ` [patch 17/29] lockup_detector: Get rid of the thread teardown/setup dance Thomas Gleixner
2017-09-01 19:08   ` Don Zickus
2017-09-01 19:45     ` Thomas Gleixner
2017-08-31  7:16 ` [patch 18/29] lockup_detector: Further simplify sysctl handling Thomas Gleixner
2017-08-31  7:16 ` [patch 19/29] lockup_detector: Cleanup header mess Thomas Gleixner
2017-08-31  7:16 ` [patch 20/29] lockup_detector/sysctl: Get rid of the ifdeffery Thomas Gleixner
2017-08-31  7:16 ` [patch 21/29] lockup_detector: Cleanup sysctl variable name space Thomas Gleixner
2017-08-31  7:16 ` [patch 22/29] lockup_detector: Make watchdog_nmi_reconfigure() two stage Thomas Gleixner
2017-08-31  7:16 ` [patch 23/29] lockup_detector: Get rid of the racy update loop Thomas Gleixner
2017-08-31  7:16 ` [patch 24/29] lockup_detector/perf: Implement init time perf validation Thomas Gleixner
2017-09-07 15:58   ` Don Zickus
2017-08-31  7:16 ` [patch 25/29] lockup_detector: Implement init time detection of perf Thomas Gleixner
2017-08-31  7:16 ` [patch 26/29] lockup_detector/perf: Implement CPU enable replacement Thomas Gleixner
2017-08-31  7:16 ` [patch 27/29] lockup_detector: Use new perf CPU enable mechanism Thomas Gleixner
2017-08-31  7:16 ` Thomas Gleixner [this message]
2017-08-31  7:16 ` [patch 29/29] lockup_detector: Cleanup hotplug locking mess Thomas Gleixner
2017-08-31 22:10 ` [patch 00/29] lockup_detector: Cure hotplug deadlocks and replace duct tape Don Zickus
2017-09-01  4:42   ` Nicholas Piggin
2017-09-01  9:18   ` Thomas Gleixner
2017-09-07 16:04 ` Don Zickus

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