From: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
To: Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@kernel.org>, "H. Peter Anvin" <hpa@zytor.com>
Cc: Andi Kleen <andi.kleen@intel.com>,
Ashok Raj <ashok.raj@intel.com>, Borislav Petkov <bp@suse.de>,
Tony Luck <tony.luck@intel.com>,
"Ravi V. Shankar" <ravi.v.shankar@intel.com>,
x86@kernel.org, sparclinux@vger.kernel.org,
linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org,
Ricardo Neri <ricardo.neri-calderon@linux.intel.com>,
Jacob Pan <jacob.jun.pan@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>,
Peter Zijlstra <peterz@infradead.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>,
iommu@lists.linux-foundation.org
Subject: [RFC PATCH 12/23] kernel/watchdog: Introduce a struct for NMI watchdog operations
Date: Tue, 12 Jun 2018 17:57:32 -0700 [thread overview]
Message-ID: <1528851463-21140-13-git-send-email-ricardo.neri-calderon@linux.intel.com> (raw)
In-Reply-To: <1528851463-21140-1-git-send-email-ricardo.neri-calderon@linux.intel.com>
Instead of exposing individual functions for the operations of the NMI
watchdog, define a common interface that can be used across multiple
implementations.
The struct nmi_watchdog_ops is defined for such operations. These initial
definitions include the enable, disable, start, stop, and cleanup
operations.
Only a single NMI watchdog can be used in the system. The operations of
this NMI watchdog are accessed via the new variable nmi_wd_ops. This
variable is set to point the operations of the first NMI watchdog that
initializes successfully. Even though at this moment, the only available
NMI watchdog is the perf-based hardlockup detector. More implementations
can be added in the future.
While introducing this new struct for the NMI watchdog operations, convert
the perf-based NMI watchdog to use these operations.
The functions hardlockup_detector_perf_restart() and
hardlockup_detector_perf_stop() are special. They are not regular watchdog
operations; they are used to work around hardware bugs. Thus, they are not
used for the start and stop operations. Furthermore, the perf-based NMI
watchdog does not need to implement such operations. They are intended to
globally start and stop the NMI watchdog; the perf-based NMI
watchdog is implemented on a per-CPU basis.
Currently, when perf-based hardlockup detector is not selected at build
time, a dummy hardlockup_detector_perf_init() is used. The return value
of this function depends on CONFIG_HAVE_NMI_WATCHDOG. This behavior is
conserved by defining using the set of NMI watchdog operations structure
hardlockup_detector_noop. These dummy operations are used when no hard-
lockup detector is used or fails to initialize.
Cc: Ashok Raj <ashok.raj@intel.com>
Cc: Andi Kleen <andi.kleen@intel.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Jacob Pan <jacob.jun.pan@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
Cc: iommu@lists.linux-foundation.org
Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
---
include/linux/nmi.h | 39 +++++++++++++++++++++++++++----------
kernel/watchdog.c | 54 +++++++++++++++++++++++++++++++++++++++++++++------
kernel/watchdog_hld.c | 16 +++++++++++----
3 files changed, 89 insertions(+), 20 deletions(-)
diff --git a/include/linux/nmi.h b/include/linux/nmi.h
index b8d868d..d3f5d55f 100644
--- a/include/linux/nmi.h
+++ b/include/linux/nmi.h
@@ -92,24 +92,43 @@ static inline void hardlockup_detector_disable(void) {}
extern void arch_touch_nmi_watchdog(void);
extern void hardlockup_detector_perf_stop(void);
extern void hardlockup_detector_perf_restart(void);
-extern void hardlockup_detector_perf_disable(void);
-extern void hardlockup_detector_perf_enable(void);
-extern void hardlockup_detector_perf_cleanup(void);
-extern int hardlockup_detector_perf_init(void);
#else
static inline void hardlockup_detector_perf_stop(void) { }
static inline void hardlockup_detector_perf_restart(void) { }
-static inline void hardlockup_detector_perf_disable(void) { }
-static inline void hardlockup_detector_perf_enable(void) { }
-static inline void hardlockup_detector_perf_cleanup(void) { }
# if !defined(CONFIG_HAVE_NMI_WATCHDOG)
-static inline int hardlockup_detector_perf_init(void) { return -ENODEV; }
static inline void arch_touch_nmi_watchdog(void) {}
-# else
-static inline int hardlockup_detector_perf_init(void) { return 0; }
# endif
#endif
+/**
+ * struct nmi_watchdog_ops - Operations performed by NMI watchdogs
+ * @init: Initialize and configure the hardware resources of the
+ * NMI watchdog.
+ * @enable: Enable (i.e., monitor for hardlockups) the NMI watchdog
+ * in the CPU in which the function is executed.
+ * @disable: Disable (i.e., do not monitor for hardlockups) the NMI
+ * in the CPU in which the function is executed.
+ * @start: Start the the NMI watchdog in all CPUs. Used after the
+ * parameters of the watchdog are updated. Optional if
+ * such updates does not impact operation the NMI watchdog.
+ * @stop: Stop the the NMI watchdog in all CPUs. Used before the
+ * parameters of the watchdog are updated. Optional if
+ * such updates does not impact the NMI watchdog.
+ * @cleanup: Cleanup unneeded data structures of the NMI watchdog.
+ * Used after updating the parameters of the watchdog.
+ * Optional no cleanup is needed.
+ */
+struct nmi_watchdog_ops {
+ int (*init)(void);
+ void (*enable)(void);
+ void (*disable)(void);
+ void (*start)(void);
+ void (*stop)(void);
+ void (*cleanup)(void);
+};
+
+extern struct nmi_watchdog_ops hardlockup_detector_perf_ops;
+
void watchdog_nmi_stop(void);
void watchdog_nmi_start(void);
int watchdog_nmi_probe(void);
diff --git a/kernel/watchdog.c b/kernel/watchdog.c
index 576d180..5057376 100644
--- a/kernel/watchdog.c
+++ b/kernel/watchdog.c
@@ -48,6 +48,8 @@ int __read_mostly soft_watchdog_user_enabled = 1;
int __read_mostly watchdog_thresh = 10;
int __read_mostly nmi_watchdog_available;
+static struct nmi_watchdog_ops *nmi_wd_ops;
+
struct cpumask watchdog_allowed_mask __read_mostly;
struct cpumask watchdog_cpumask __read_mostly;
@@ -99,6 +101,23 @@ __setup("hardlockup_all_cpu_backtrace=", hardlockup_all_cpu_backtrace_setup);
#endif /* CONFIG_HARDLOCKUP_DETECTOR */
/*
+ * Define a non-existent hard lockup detector. It will be used only if
+ * no actual hardlockup detector was selected at built time.
+ */
+static inline int noop_hardlockup_detector_init(void)
+{
+ /* If arch has an NMI watchdog, pretend to initialize it. */
+ if (IS_ENABLED(CONFIG_HAVE_NMI_WATCHDOG))
+ return 0;
+ else
+ return -ENODEV;
+}
+
+static struct nmi_watchdog_ops hardlockup_detector_noop = {
+ .init = noop_hardlockup_detector_init,
+};
+
+/*
* These functions can be overridden if an architecture implements its
* own hardlockup detector.
*
@@ -108,19 +127,33 @@ __setup("hardlockup_all_cpu_backtrace=", hardlockup_all_cpu_backtrace_setup);
*/
int __weak watchdog_nmi_enable(unsigned int cpu)
{
- hardlockup_detector_perf_enable();
+ if (nmi_wd_ops && nmi_wd_ops->enable)
+ nmi_wd_ops->enable();
+
return 0;
}
void __weak watchdog_nmi_disable(unsigned int cpu)
{
- hardlockup_detector_perf_disable();
+ if (nmi_wd_ops && nmi_wd_ops->disable)
+ nmi_wd_ops->disable();
}
/* Return 0, if a NMI watchdog is available. Error code otherwise */
int __weak __init watchdog_nmi_probe(void)
{
- return hardlockup_detector_perf_init();
+ int ret = -ENODEV;
+
+ if (IS_ENABLED(CONFIG_HARDLOCKUP_DETECTOR_PERF))
+ ret = hardlockup_detector_perf_ops.init();
+
+ if (!ret) {
+ nmi_wd_ops = &hardlockup_detector_perf_ops;
+ return ret;
+ }
+
+ nmi_wd_ops = &hardlockup_detector_noop;
+ return nmi_wd_ops->init();
}
/**
@@ -131,7 +164,11 @@ int __weak __init watchdog_nmi_probe(void)
* update_variables();
* watchdog_nmi_start();
*/
-void __weak watchdog_nmi_stop(void) { }
+void __weak watchdog_nmi_stop(void)
+{
+ if (nmi_wd_ops && nmi_wd_ops->stop)
+ nmi_wd_ops->stop();
+}
/**
* watchdog_nmi_start - Start the watchdog after reconfiguration
@@ -144,7 +181,11 @@ void __weak watchdog_nmi_stop(void) { }
* - watchdog_thresh
* - watchdog_cpumask
*/
-void __weak watchdog_nmi_start(void) { }
+void __weak watchdog_nmi_start(void)
+{
+ if (nmi_wd_ops && nmi_wd_ops->start)
+ nmi_wd_ops->start();
+}
/**
* lockup_detector_update_enable - Update the sysctl enable bit
@@ -627,7 +668,8 @@ static inline void lockup_detector_setup(void)
static void __lockup_detector_cleanup(void)
{
lockdep_assert_held(&watchdog_mutex);
- hardlockup_detector_perf_cleanup();
+ if (nmi_wd_ops && nmi_wd_ops->cleanup)
+ nmi_wd_ops->cleanup();
}
/**
diff --git a/kernel/watchdog_hld.c b/kernel/watchdog_hld.c
index e449a23..036cb0a 100644
--- a/kernel/watchdog_hld.c
+++ b/kernel/watchdog_hld.c
@@ -186,7 +186,7 @@ static int hardlockup_detector_event_create(void)
/**
* hardlockup_detector_perf_enable - Enable the local event
*/
-void hardlockup_detector_perf_enable(void)
+static void hardlockup_detector_perf_enable(void)
{
if (hardlockup_detector_event_create())
return;
@@ -201,7 +201,7 @@ void hardlockup_detector_perf_enable(void)
/**
* hardlockup_detector_perf_disable - Disable the local event
*/
-void hardlockup_detector_perf_disable(void)
+static void hardlockup_detector_perf_disable(void)
{
struct perf_event *event = this_cpu_read(watchdog_ev);
@@ -219,7 +219,7 @@ void hardlockup_detector_perf_disable(void)
*
* Called from lockup_detector_cleanup(). Serialized by the caller.
*/
-void hardlockup_detector_perf_cleanup(void)
+static void hardlockup_detector_perf_cleanup(void)
{
int cpu;
@@ -281,7 +281,7 @@ void __init hardlockup_detector_perf_restart(void)
/**
* hardlockup_detector_perf_init - Probe whether NMI event is available at all
*/
-int __init hardlockup_detector_perf_init(void)
+static int __init hardlockup_detector_perf_init(void)
{
int ret = hardlockup_detector_event_create();
@@ -291,5 +291,13 @@ int __init hardlockup_detector_perf_init(void)
perf_event_release_kernel(this_cpu_read(watchdog_ev));
this_cpu_write(watchdog_ev, NULL);
}
+
return ret;
}
+
+struct nmi_watchdog_ops hardlockup_detector_perf_ops = {
+ .init = hardlockup_detector_perf_init,
+ .enable = hardlockup_detector_perf_enable,
+ .disable = hardlockup_detector_perf_disable,
+ .cleanup = hardlockup_detector_perf_cleanup,
+};
--
2.7.4
next prev parent reply other threads:[~2018-06-13 1:04 UTC|newest]
Thread overview: 70+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-06-13 0:57 [RFC PATCH 00/23] Implement an HPET-based hardlockup detector Ricardo Neri
2018-06-13 0:57 ` [RFC PATCH 01/23] x86/apic: Add a parameter for the APIC delivery mode Ricardo Neri
2018-06-13 0:57 ` [RFC PATCH 02/23] genirq: Introduce IRQD_DELIVER_AS_NMI Ricardo Neri
2018-06-13 0:57 ` [RFC PATCH 03/23] genirq: Introduce IRQF_DELIVER_AS_NMI Ricardo Neri
2018-06-13 8:34 ` Peter Zijlstra
2018-06-13 8:59 ` Julien Thierry
2018-06-13 9:20 ` Thomas Gleixner
2018-06-13 9:36 ` Julien Thierry
2018-06-13 9:49 ` Julien Thierry
2018-06-13 9:57 ` Thomas Gleixner
2018-06-13 10:25 ` Julien Thierry
2018-06-13 10:06 ` Marc Zyngier
2018-06-15 2:12 ` Ricardo Neri
2018-06-15 8:01 ` Julien Thierry
2018-06-16 0:39 ` Ricardo Neri
2018-06-16 13:36 ` Thomas Gleixner
2018-06-13 0:57 ` [RFC PATCH 04/23] iommu/vt-d/irq_remapping: Add support for IRQCHIP_CAN_DELIVER_AS_NMI Ricardo Neri
2018-06-13 0:57 ` [RFC PATCH 05/23] x86/msi: " Ricardo Neri
2018-06-13 0:57 ` [RFC PATCH 06/23] x86/ioapic: Add support for IRQCHIP_CAN_DELIVER_AS_NMI with interrupt remapping Ricardo Neri
2018-06-13 0:57 ` [RFC PATCH 07/23] x86/hpet: Expose more functions to read and write registers Ricardo Neri
2018-06-13 0:57 ` [RFC PATCH 08/23] x86/hpet: Calculate ticks-per-second in a separate function Ricardo Neri
2018-06-13 0:57 ` [RFC PATCH 09/23] x86/hpet: Reserve timer for the HPET hardlockup detector Ricardo Neri
2018-06-13 0:57 ` [RFC PATCH 10/23] x86/hpet: Relocate flag definitions to a header file Ricardo Neri
2018-06-13 0:57 ` [RFC PATCH 11/23] x86/hpet: Configure the timer used by the hardlockup detector Ricardo Neri
2018-06-13 0:57 ` Ricardo Neri [this message]
2018-06-13 7:41 ` [RFC PATCH 12/23] kernel/watchdog: Introduce a struct for NMI watchdog operations Nicholas Piggin
2018-06-13 8:42 ` Peter Zijlstra
2018-06-13 9:26 ` Thomas Gleixner
2018-06-13 11:52 ` Nicholas Piggin
2018-06-14 1:31 ` Ricardo Neri
2018-06-14 2:32 ` Nicholas Piggin
2018-06-14 8:32 ` Thomas Gleixner
2018-06-15 2:21 ` Ricardo Neri
2018-06-14 1:26 ` Ricardo Neri
2018-06-13 0:57 ` [RFC PATCH 13/23] watchdog/hardlockup: Define a generic function to detect hardlockups Ricardo Neri
2018-06-13 0:57 ` [RFC PATCH 14/23] watchdog/hardlockup: Decouple the hardlockup detector from perf Ricardo Neri
2018-06-13 8:43 ` Peter Zijlstra
2018-06-14 1:19 ` Ricardo Neri
2018-06-14 1:41 ` Nicholas Piggin
2018-06-15 2:23 ` Ricardo Neri
2018-06-13 0:57 ` [RFC PATCH 15/23] kernel/watchdog: Add a function to obtain the watchdog_allowed_mask Ricardo Neri
2018-06-13 0:57 ` [RFC PATCH 16/23] watchdog/hardlockup: Add an HPET-based hardlockup detector Ricardo Neri
2018-06-13 5:23 ` Randy Dunlap
2018-06-14 1:00 ` Ricardo Neri
2018-06-13 0:57 ` [RFC PATCH 17/23] watchdog/hardlockup/hpet: Convert the timer's interrupt to NMI Ricardo Neri
2018-06-13 9:07 ` Peter Zijlstra
2018-06-15 2:07 ` Ricardo Neri
2018-06-13 9:40 ` Thomas Gleixner
2018-06-15 2:03 ` Ricardo Neri
2018-06-15 9:19 ` Thomas Gleixner
2018-06-16 0:51 ` Ricardo Neri
2018-06-16 13:24 ` Thomas Gleixner
2018-06-20 0:15 ` Ricardo Neri
2018-06-20 0:25 ` Randy Dunlap
2018-06-21 0:25 ` Ricardo Neri
2018-06-20 7:47 ` Thomas Gleixner
2018-06-13 0:57 ` [RFC PATCH 18/23] watchdog/hardlockup/hpet: Add the NMI watchdog operations Ricardo Neri
2018-06-13 0:57 ` [RFC PATCH 19/23] watchdog/hardlockup: Make arch_touch_nmi_watchdog() to hpet-based implementation Ricardo Neri
2018-06-13 0:57 ` [RFC PATCH 20/23] watchdog/hardlockup/hpet: Rotate interrupt among all monitored CPUs Ricardo Neri
2018-06-13 9:48 ` Thomas Gleixner
2018-06-15 2:16 ` Ricardo Neri
2018-06-15 10:29 ` Thomas Gleixner
2018-06-16 0:46 ` Ricardo Neri
2018-06-16 13:27 ` Thomas Gleixner
2018-06-13 0:57 ` [RFC PATCH 21/23] watchdog/hardlockup/hpet: Adjust timer expiration on the number of " Ricardo Neri
2018-06-13 0:57 ` [RFC PATCH 22/23] watchdog/hardlockup/hpet: Only enable the HPET watchdog via a boot parameter Ricardo Neri
2018-06-13 5:26 ` Randy Dunlap
2018-06-14 0:58 ` Ricardo Neri
2018-06-14 3:30 ` Randy Dunlap
2018-06-13 0:57 ` [RFC PATCH 23/23] watchdog/hardlockup: Activate the HPET-based lockup detector Ricardo Neri
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1528851463-21140-13-git-send-email-ricardo.neri-calderon@linux.intel.com \
--to=ricardo.neri-calderon@linux.intel.com \
--cc=akpm@linux-foundation.org \
--cc=andi.kleen@intel.com \
--cc=ashok.raj@intel.com \
--cc=babu.moger@oracle.com \
--cc=benh@kernel.crashing.org \
--cc=bp@suse.de \
--cc=colin.king@canonical.com \
--cc=davem@davemloft.net \
--cc=dzickus@redhat.com \
--cc=frederic@kernel.org \
--cc=hpa@zytor.com \
--cc=iommu@lists.linux-foundation.org \
--cc=jacob.jun.pan@intel.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linuxppc-dev@lists.ozlabs.org \
--cc=mathieu.desnoyers@efficios.com \
--cc=mcgrof@kernel.org \
--cc=mhiramat@kernel.org \
--cc=mingo@kernel.org \
--cc=mpe@ellerman.id.au \
--cc=npiggin@gmail.com \
--cc=paulus@samba.org \
--cc=peterz@infradead.org \
--cc=pombredanne@nexb.com \
--cc=ravi.v.shankar@intel.com \
--cc=sparclinux@vger.kernel.org \
--cc=tglx@linutronix.de \
--cc=tony.luck@intel.com \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).