From: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
To: Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@kernel.org>, Borislav Petkov <bp@suse.de>
Cc: Ashok Raj <ashok.raj@intel.com>,
Andi Kleen <andi.kleen@intel.com>,
Peter Zijlstra <peterz@infradead.org>,
"Ravi V. Shankar" <ravi.v.shankar@intel.com>,
x86@kernel.org, linux-kernel@vger.kernel.org,
Ricardo Neri <ricardo.neri@intel.com>,
Ricardo Neri <ricardo.neri-calderon@linux.intel.com>,
"H. Peter Anvin" <hpa@zytor.com>, Tony Luck <tony.luck@intel.com>,
Don Zickus <dzickus@redhat.com>,
Nicholas Piggin <npiggin@gmail.com>,
Michael Ellerman <mpe@ellerman.id.au>,
Frederic Weisbecker <frederic@kernel.org>,
Babu Moger <babu.moger@oracle.com>,
"David S. Miller" <davem@davemloft.net>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Masami Hiramatsu <mhiramat@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Philippe Ombredanne <pombredanne@nexb.com>,
Colin Ian King <colin.king@canonical.com>,
"Luis R. Rodriguez" <mcgrof@kernel.org>,
sparclinux@vger.kernel.org, linuxppc-dev@lists.ozlabs.org
Subject: [RFC PATCH v2 08/14] watchdog/hardlockup: Decouple the hardlockup detector from perf
Date: Wed, 27 Feb 2019 08:05:12 -0800 [thread overview]
Message-ID: <1551283518-18922-9-git-send-email-ricardo.neri-calderon@linux.intel.com> (raw)
In-Reply-To: <1551283518-18922-1-git-send-email-ricardo.neri-calderon@linux.intel.com>
The current default implementation of the hardlockup detector assumes that
it is implemented using perf events. However, the hardlockup detector can
be driven by other sources of non-maskable interrupts (e.g., a properly
configured timer).
Put in a separate file all the code that is specific to perf: create and
manage events, stop and start the detector. This perf-specific code is put
in the new file watchdog_hld_perf.c
The code generic code used to monitor the timers' thresholds, check
timestamps and detect hardlockups remains in watchdog_hld.c
Functions and variables are simply relocated to a new file. No functional
changes were made.
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ashok Raj <ashok.raj@intel.com>
Cc: Andi Kleen <andi.kleen@intel.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Frederic Weisbecker <frederic@kernel.org>
Cc: Babu Moger <babu.moger@oracle.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Philippe Ombredanne <pombredanne@nexb.com>
Cc: Colin Ian King <colin.king@canonical.com>
Cc: "Luis R. Rodriguez" <mcgrof@kernel.org>
Cc: "Ravi V. Shankar" <ravi.v.shankar@intel.com>
Cc: x86@kernel.org
Cc: sparclinux@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
---
kernel/Makefile | 3 +-
kernel/watchdog_hld.c | 153 --------------------------------
kernel/watchdog_hld_perf.c | 175 +++++++++++++++++++++++++++++++++++++
3 files changed, 177 insertions(+), 154 deletions(-)
create mode 100644 kernel/watchdog_hld_perf.c
diff --git a/kernel/Makefile b/kernel/Makefile
index 6aa7543bcdb2..5b75e6003458 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -81,7 +81,8 @@ obj-$(CONFIG_FAIL_FUNCTION) += fail_function.o
obj-$(CONFIG_KGDB) += debug/
obj-$(CONFIG_DETECT_HUNG_TASK) += hung_task.o
obj-$(CONFIG_LOCKUP_DETECTOR) += watchdog.o
-obj-$(CONFIG_HARDLOCKUP_DETECTOR_PERF) += watchdog_hld.o
+obj-$(CONFIG_HARDLOCKUP_DETECTOR) += watchdog_hld.o
+obj-$(CONFIG_HARDLOCKUP_DETECTOR_PERF) += watchdog_hld_perf.o
obj-$(CONFIG_SECCOMP) += seccomp.o
obj-$(CONFIG_RELAY) += relay.o
obj-$(CONFIG_SYSCTL) += utsname_sysctl.o
diff --git a/kernel/watchdog_hld.c b/kernel/watchdog_hld.c
index 9724cd57307b..372db565b1b9 100644
--- a/kernel/watchdog_hld.c
+++ b/kernel/watchdog_hld.c
@@ -22,12 +22,8 @@
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;
-static atomic_t watchdog_cpus = ATOMIC_INIT(0);
notrace void arch_touch_nmi_watchdog(void)
{
@@ -98,14 +94,6 @@ static inline bool watchdog_check_timestamp(void)
}
#endif
-static struct perf_event_attr wd_hw_attr = {
- .type = PERF_TYPE_HARDWARE,
- .config = PERF_COUNT_HW_CPU_CYCLES,
- .size = sizeof(struct perf_event_attr),
- .pinned = 1,
- .disabled = 1,
-};
-
void inspect_for_hardlockups(struct pt_regs *regs)
{
if (__this_cpu_read(watchdog_nmi_touch) == true) {
@@ -156,144 +144,3 @@ void inspect_for_hardlockups(struct pt_regs *regs)
return;
}
-/* Callback function for perf event subsystem */
-static void watchdog_overflow_callback(struct perf_event *event,
- struct perf_sample_data *data,
- struct pt_regs *regs)
-{
- /* Ensure the watchdog never gets throttled */
- event->hw.interrupts = 0;
- inspect_for_hardlockups(regs);
-}
-
-static int hardlockup_detector_event_create(void)
-{
- unsigned int cpu = smp_processor_id();
- struct perf_event_attr *wd_attr;
- struct perf_event *evt;
-
- wd_attr = &wd_hw_attr;
- wd_attr->sample_period = hw_nmi_get_sample_period(watchdog_thresh);
-
- /* Try to register using hardware perf events */
- evt = perf_event_create_kernel_counter(wd_attr, cpu, NULL,
- watchdog_overflow_callback, NULL);
- if (IS_ERR(evt)) {
- pr_debug("Perf event create on CPU %d failed with %ld\n", cpu,
- PTR_ERR(evt));
- return PTR_ERR(evt);
- }
- this_cpu_write(watchdog_ev, evt);
- return 0;
-}
-
-/**
- * hardlockup_detector_perf_enable - Enable the local event
- */
-void hardlockup_detector_perf_enable(void)
-{
- if (hardlockup_detector_event_create())
- return;
-
- /* use original value for check */
- if (!atomic_fetch_inc(&watchdog_cpus))
- pr_info("Enabled. Permanently consumes one hw-PMU counter.\n");
-
- perf_event_enable(this_cpu_read(watchdog_ev));
-}
-
-/**
- * hardlockup_detector_perf_disable - Disable the local event
- */
-void hardlockup_detector_perf_disable(void)
-{
- struct perf_event *event = this_cpu_read(watchdog_ev);
-
- 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);
- atomic_dec(&watchdog_cpus);
- }
-}
-
-/**
- * hardlockup_detector_perf_cleanup - Cleanup disabled events and destroy them
- *
- * Called from lockup_detector_cleanup(). Serialized by the caller.
- */
-void hardlockup_detector_perf_cleanup(void)
-{
- int cpu;
-
- for_each_cpu(cpu, &dead_events_mask) {
- struct perf_event *event = per_cpu(dead_event, cpu);
-
- /*
- * Required because for_each_cpu() reports unconditionally
- * CPU0 as set on UP kernels. Sigh.
- */
- if (event)
- perf_event_release_kernel(event);
- per_cpu(dead_event, cpu) = NULL;
- }
- cpumask_clear(&dead_events_mask);
-}
-
-/**
- * hardlockup_detector_perf_stop - Globally stop watchdog events
- *
- * Special interface for x86 to handle the perf HT bug.
- */
-void __init hardlockup_detector_perf_stop(void)
-{
- int cpu;
-
- lockdep_assert_cpus_held();
-
- for_each_online_cpu(cpu) {
- struct perf_event *event = per_cpu(watchdog_ev, cpu);
-
- if (event)
- perf_event_disable(event);
- }
-}
-
-/**
- * hardlockup_detector_perf_restart - Globally restart watchdog events
- *
- * Special interface for x86 to handle the perf HT bug.
- */
-void __init hardlockup_detector_perf_restart(void)
-{
- int cpu;
-
- lockdep_assert_cpus_held();
-
- if (!(watchdog_enabled & NMI_WATCHDOG_ENABLED))
- return;
-
- for_each_online_cpu(cpu) {
- struct perf_event *event = per_cpu(watchdog_ev, cpu);
-
- if (event)
- perf_event_enable(event);
- }
-}
-
-/**
- * hardlockup_detector_perf_init - Probe whether NMI event is available at all
- */
-int __init hardlockup_detector_perf_init(void)
-{
- int ret = hardlockup_detector_event_create();
-
- if (ret) {
- pr_info("Perf NMI watchdog permanently disabled\n");
- } else {
- perf_event_release_kernel(this_cpu_read(watchdog_ev));
- this_cpu_write(watchdog_ev, NULL);
- }
- return ret;
-}
diff --git a/kernel/watchdog_hld_perf.c b/kernel/watchdog_hld_perf.c
new file mode 100644
index 000000000000..1d06ec5a8e42
--- /dev/null
+++ b/kernel/watchdog_hld_perf.c
@@ -0,0 +1,175 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Detect hard lockups on a system
+ *
+ * Copyright (C) Intel Corporation 2019
+ *
+ * Note: All of this code comes from the original perf-specific hardlockup
+ * detector.
+ */
+
+#define pr_fmt(fmt) "NMI perf watchdog: " fmt
+
+#include <linux/nmi.h>
+#include <linux/atomic.h>
+#include <linux/module.h>
+#include <linux/sched/debug.h>
+#include <linux/perf_event.h>
+#include <asm/irq_regs.h>
+
+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 atomic_t watchdog_cpus = ATOMIC_INIT(0);
+
+static struct perf_event_attr wd_hw_attr = {
+ .type = PERF_TYPE_HARDWARE,
+ .config = PERF_COUNT_HW_CPU_CYCLES,
+ .size = sizeof(struct perf_event_attr),
+ .pinned = 1,
+ .disabled = 1,
+};
+
+/* Callback function for perf event subsystem */
+static void watchdog_overflow_callback(struct perf_event *event,
+ struct perf_sample_data *data,
+ struct pt_regs *regs)
+{
+ /* Ensure the watchdog never gets throttled */
+ event->hw.interrupts = 0;
+ inspect_for_hardlockups(regs);
+}
+
+static int hardlockup_detector_event_create(void)
+{
+ unsigned int cpu = smp_processor_id();
+ struct perf_event_attr *wd_attr;
+ struct perf_event *evt;
+
+ wd_attr = &wd_hw_attr;
+ wd_attr->sample_period = hw_nmi_get_sample_period(watchdog_thresh);
+
+ /* Try to register using hardware perf events */
+ evt = perf_event_create_kernel_counter(wd_attr, cpu, NULL,
+ watchdog_overflow_callback, NULL);
+ if (IS_ERR(evt)) {
+ pr_debug("Perf event create on CPU %d failed with %ld\n", cpu,
+ PTR_ERR(evt));
+ return PTR_ERR(evt);
+ }
+ this_cpu_write(watchdog_ev, evt);
+ return 0;
+}
+
+/**
+ * hardlockup_detector_perf_enable - Enable the local event
+ */
+void hardlockup_detector_perf_enable(void)
+{
+ if (hardlockup_detector_event_create())
+ return;
+
+ /* use original value for check */
+ if (!atomic_fetch_inc(&watchdog_cpus))
+ pr_info("Enabled. Permanently consumes one hw-PMU counter.\n");
+
+ perf_event_enable(this_cpu_read(watchdog_ev));
+}
+
+/**
+ * hardlockup_detector_perf_disable - Disable the local event
+ */
+void hardlockup_detector_perf_disable(void)
+{
+ struct perf_event *event = this_cpu_read(watchdog_ev);
+
+ 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);
+ atomic_dec(&watchdog_cpus);
+ }
+}
+
+/**
+ * hardlockup_detector_perf_cleanup - Cleanup disabled events and destroy them
+ *
+ * Called from lockup_detector_cleanup(). Serialized by the caller.
+ */
+void hardlockup_detector_perf_cleanup(void)
+{
+ int cpu;
+
+ for_each_cpu(cpu, &dead_events_mask) {
+ struct perf_event *event = per_cpu(dead_event, cpu);
+
+ /*
+ * Required because for_each_cpu() reports unconditionally
+ * CPU0 as set on UP kernels. Sigh.
+ */
+ if (event)
+ perf_event_release_kernel(event);
+ per_cpu(dead_event, cpu) = NULL;
+ }
+ cpumask_clear(&dead_events_mask);
+}
+
+/**
+ * hardlockup_detector_perf_stop - Globally stop watchdog events
+ *
+ * Special interface for x86 to handle the perf HT bug.
+ */
+void __init hardlockup_detector_perf_stop(void)
+{
+ int cpu;
+
+ lockdep_assert_cpus_held();
+
+ for_each_online_cpu(cpu) {
+ struct perf_event *event = per_cpu(watchdog_ev, cpu);
+
+ if (event)
+ perf_event_disable(event);
+ }
+}
+
+/**
+ * hardlockup_detector_perf_restart - Globally restart watchdog events
+ *
+ * Special interface for x86 to handle the perf HT bug.
+ */
+void __init hardlockup_detector_perf_restart(void)
+{
+ int cpu;
+
+ lockdep_assert_cpus_held();
+
+ if (!(watchdog_enabled & NMI_WATCHDOG_ENABLED))
+ return;
+
+ for_each_online_cpu(cpu) {
+ struct perf_event *event = per_cpu(watchdog_ev, cpu);
+
+ if (event)
+ perf_event_enable(event);
+ }
+}
+
+/**
+ * hardlockup_detector_perf_init - Probe whether NMI event is available at all
+ */
+int __init hardlockup_detector_perf_init(void)
+{
+ int ret = hardlockup_detector_event_create();
+
+ if (ret) {
+ pr_info("Perf NMI watchdog permanently disabled\n");
+ } else {
+ perf_event_release_kernel(this_cpu_read(watchdog_ev));
+ this_cpu_write(watchdog_ev, NULL);
+ }
+ return ret;
+}
+
--
2.17.1
next prev parent reply other threads:[~2019-02-27 16:05 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-27 16:05 [RFC PATCH v2 00/14] Implement an HPET-based hardlockup detector Ricardo Neri
2019-02-27 16:05 ` [RFC PATCH v2 01/14] x86/msi: Add definition for NMI delivery mode Ricardo Neri
2019-02-27 16:05 ` [RFC PATCH v2 02/14] x86/hpet: Expose more functions to read and write registers Ricardo Neri
2019-03-26 21:00 ` Thomas Gleixner
2019-04-09 2:03 ` Ricardo Neri
2019-02-27 16:05 ` [RFC PATCH v2 03/14] x86/hpet: Calculate ticks-per-second in a separate function Ricardo Neri
2019-03-26 21:03 ` Thomas Gleixner
2019-04-09 2:04 ` Ricardo Neri
2019-02-27 16:05 ` [RFC PATCH v2 04/14] x86/hpet: Reserve timer for the HPET hardlockup detector Ricardo Neri
2019-02-27 16:05 ` [RFC PATCH v2 05/14] x86/hpet: Relocate flag definitions to a header file Ricardo Neri
2019-03-26 21:11 ` Thomas Gleixner
2019-04-09 2:04 ` Ricardo Neri
2019-02-27 16:05 ` [RFC PATCH v2 06/14] x86/hpet: Configure the timer used by the hardlockup detector Ricardo Neri
2019-03-26 21:13 ` Thomas Gleixner
2019-04-09 2:04 ` Ricardo Neri
2019-02-27 16:05 ` [RFC PATCH v2 07/14] watchdog/hardlockup: Define a generic function to detect hardlockups Ricardo Neri
2019-02-27 16:05 ` Ricardo Neri [this message]
2019-03-26 21:18 ` [RFC PATCH v2 08/14] watchdog/hardlockup: Decouple the hardlockup detector from perf Thomas Gleixner
2019-04-09 2:05 ` Ricardo Neri
2019-02-27 16:05 ` [RFC PATCH v2 09/14] watchdog/hardlockup: Make arch_touch_nmi_watchdog() to hpet-based implementation Ricardo Neri
2019-02-27 16:17 ` Paul E. McKenney
2019-03-01 1:17 ` Ricardo Neri
2019-03-26 21:20 ` Thomas Gleixner
2019-04-09 2:05 ` Ricardo Neri
2019-02-27 16:05 ` [RFC PATCH v2 10/14] kernel/watchdog: Add a function to obtain the watchdog_allowed_mask Ricardo Neri
2019-03-26 21:22 ` Thomas Gleixner
2019-04-09 2:05 ` Ricardo Neri
2019-04-09 11:34 ` Peter Zijlstra
2019-04-11 1:15 ` Ricardo Neri
2019-02-27 16:05 ` [RFC PATCH v2 11/14] x86/watchdog/hardlockup: Add an HPET-based hardlockup detector Ricardo Neri
2019-03-26 20:49 ` Thomas Gleixner
2019-04-09 2:02 ` Ricardo Neri
2019-04-09 10:59 ` Peter Zijlstra
2019-04-10 1:13 ` Ricardo Neri
2019-04-05 16:12 ` Suthikulpanit, Suravee
2019-04-09 2:14 ` Ricardo Neri
2019-04-09 11:03 ` Peter Zijlstra
2019-04-10 1:05 ` Ricardo Neri
2019-02-27 16:05 ` [RFC PATCH v2 12/14] x86/watchdog/hardlockup/hpet: Determine if HPET timer caused NMI Ricardo Neri
2019-03-26 20:55 ` Thomas Gleixner
2019-04-09 2:02 ` Ricardo Neri
2019-04-09 11:28 ` Peter Zijlstra
2019-04-10 1:19 ` Ricardo Neri
2019-04-10 7:01 ` Peter Zijlstra
2019-04-11 1:12 ` Ricardo Neri
2019-02-27 16:05 ` [RFC PATCH v2 13/14] watchdog/hardlockup/hpet: Only enable the HPET watchdog via a boot parameter Ricardo Neri
2019-03-26 21:29 ` Thomas Gleixner
2019-04-09 2:07 ` Ricardo Neri
2019-02-27 16:05 ` [RFC PATCH v2 14/14] x86/watchdog: Add a shim hardlockup detector Ricardo Neri
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