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From: Douglas Anderson <dianders@chromium.org>
To: Petr Mladek <pmladek@suse.com>,
	Andrew Morton <akpm@linux-foundation.org>
Cc: Matthias Kaehlcke <mka@chromium.org>,
	kgdb-bugreport@lists.sourceforge.net,
	Stephane Eranian <eranian@google.com>,
	mpe@ellerman.id.au, Tzung-Bi Shih <tzungbi@chromium.org>,
	Daniel Thompson <daniel.thompson@linaro.org>,
	Mark Rutland <mark.rutland@arm.com>,
	linuxppc-dev@lists.ozlabs.org, Sumit Garg <sumit.garg@linaro.org>,
	npiggin@gmail.com, davem@davemloft.net,
	Marc Zyngier <maz@kernel.org>, Stephen Boyd <swboyd@chromium.org>,
	sparclinux@vger.kernel.org, christophe.leroy@csgroup.eu,
	Catalin Marinas <catalin.marinas@arm.com>,
	ravi.v.shankar@intel.com, Randy Dunlap <rdunlap@infradead.org>,
	Pingfan Liu <kernelfans@gmail.com>,
	Guenter Roeck <groeck@chromium.org>,
	Lecopzer Chen <lecopzer.chen@mediatek.com>,
	Ian Rogers <irogers@google.com>,
	ito-yuichi@fujitsu.com, ricardo.neri@intel.com,
	linux-arm-kernel@lists.infradead.org,
	linux-perf-users@vger.kernel.org, Will Deacon <will@kernel.org>,
	Chen-Yu Tsai <wens@csie.org>,
	linux-kernel@vger.kernel.org,
	Masayoshi Mizuma <msys.mizuma@gmail.com>,
	Andi Kleen <ak@linux.intel.com>,
	Douglas Anderson <dianders@chromium.org>
Subject: [PATCH v5 09/18] watchdog/hardlockup: Style changes to watchdog_hardlockup_check() / is_hardlockup()
Date: Fri, 19 May 2023 10:18:33 -0700	[thread overview]
Message-ID: <20230519101840.v5.9.I818492c326b632560b09f20d2608455ecf9d3650@changeid> (raw)
In-Reply-To: <20230519101840.v5.18.Ia44852044cdcb074f387e80df6b45e892965d4a1@changeid>

These are tiny style changes:
- Add a blank line before a "return".
- Renames two globals to use the "watchdog_hardlockup" prefix.
- Store processor id in "unsigned int" rather than "int".
- Minor comment rewording.
- Use "else" rather than extra returns since it seemed more symmetric.

Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
---

Changes in v5:
- watchdog_hardlockup_dumped_stacks => watchdog_hardlockup_all_cpu_dumped
- watchdog_hardlockup_processed => watchdog_hardlockup_warned

Changes in v4:
- ("Style changes to watchdog_hardlockup_check ...") new for v4.

 kernel/watchdog.c | 32 +++++++++++++++-----------------
 1 file changed, 15 insertions(+), 17 deletions(-)

diff --git a/kernel/watchdog.c b/kernel/watchdog.c
index 12ce37d76e7d..169e5dffbc00 100644
--- a/kernel/watchdog.c
+++ b/kernel/watchdog.c
@@ -89,8 +89,8 @@ __setup("nmi_watchdog=", hardlockup_panic_setup);
 
 static DEFINE_PER_CPU(unsigned long, hrtimer_interrupts);
 static DEFINE_PER_CPU(unsigned long, hrtimer_interrupts_saved);
-static DEFINE_PER_CPU(bool, hard_watchdog_warn);
-static unsigned long hardlockup_allcpu_dumped;
+static DEFINE_PER_CPU(bool, watchdog_hardlockup_warned);
+static unsigned long watchdog_hardlockup_all_cpu_dumped;
 
 static bool is_hardlockup(void)
 {
@@ -100,6 +100,7 @@ static bool is_hardlockup(void)
 		return true;
 
 	__this_cpu_write(hrtimer_interrupts_saved, hrint);
+
 	return false;
 }
 
@@ -110,21 +111,20 @@ static void watchdog_hardlockup_kick(void)
 
 void watchdog_hardlockup_check(struct pt_regs *regs)
 {
-	/* check for a hardlockup
-	 * This is done by making sure our timer interrupt
-	 * is incrementing.  The timer interrupt should have
-	 * fired multiple times before we overflow'd.  If it hasn't
+	/*
+	 * Check for a hardlockup by making sure the CPU's timer
+	 * interrupt is incrementing. The timer interrupt should have
+	 * fired multiple times before we overflow'd. If it hasn't
 	 * then this is a good indication the cpu is stuck
 	 */
 	if (is_hardlockup()) {
-		int this_cpu = smp_processor_id();
+		unsigned int this_cpu = smp_processor_id();
 
-		/* only print hardlockups once */
-		if (__this_cpu_read(hard_watchdog_warn) == true)
+		/* Only print hardlockups once. */
+		if (__this_cpu_read(watchdog_hardlockup_warned))
 			return;
 
-		pr_emerg("Watchdog detected hard LOCKUP on cpu %d\n",
-			 this_cpu);
+		pr_emerg("Watchdog detected hard LOCKUP on cpu %d\n", this_cpu);
 		print_modules();
 		print_irqtrace_events(current);
 		if (regs)
@@ -137,18 +137,16 @@ void watchdog_hardlockup_check(struct pt_regs *regs)
 		 * generating interleaving traces
 		 */
 		if (sysctl_hardlockup_all_cpu_backtrace &&
-				!test_and_set_bit(0, &hardlockup_allcpu_dumped))
+		    !test_and_set_bit(0, &watchdog_hardlockup_all_cpu_dumped))
 			trigger_allbutself_cpu_backtrace();
 
 		if (hardlockup_panic)
 			nmi_panic(regs, "Hard LOCKUP");
 
-		__this_cpu_write(hard_watchdog_warn, true);
-		return;
+		__this_cpu_write(watchdog_hardlockup_warned, true);
+	} else {
+		__this_cpu_write(watchdog_hardlockup_warned, false);
 	}
-
-	__this_cpu_write(hard_watchdog_warn, false);
-	return;
 }
 
 #else /* CONFIG_HARDLOCKUP_DETECTOR_PERF */
-- 
2.40.1.698.g37aff9b760-goog


  parent reply	other threads:[~2023-05-19 17:21 UTC|newest]

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-05-19 17:18 [PATCH v5 00/18] watchdog/hardlockup: Add the buddy hardlockup detector Douglas Anderson
2023-05-19 17:18 ` [PATCH v5 01/18] watchdog/perf: Define dummy watchdog_update_hrtimer_threshold() on correct config Douglas Anderson
2023-05-19 17:18 ` [PATCH v5 02/18] watchdog/perf: More properly prevent false positives with turbo modes Douglas Anderson
2023-05-23  9:35   ` Petr Mladek
2023-05-19 17:18 ` [PATCH v5 03/18] watchdog: remove WATCHDOG_DEFAULT Douglas Anderson
2023-05-19 17:18 ` [PATCH v5 04/18] watchdog/hardlockup: change watchdog_nmi_enable() to void Douglas Anderson
2023-05-19 17:18 ` [PATCH v5 05/18] watchdog/perf: Ensure CPU-bound context when creating hardlockup detector event Douglas Anderson
2023-05-19 17:18 ` [PATCH v5 06/18] watchdog/hardlockup: Add comments to touch_nmi_watchdog() Douglas Anderson
2023-05-23  9:58   ` Petr Mladek
2023-05-19 17:18 ` [PATCH v5 07/18] watchdog/perf: Rename watchdog_hld.c to watchdog_perf.c Douglas Anderson
2023-05-19 17:18 ` [PATCH v5 08/18] watchdog/hardlockup: Move perf hardlockup checking/panic to common watchdog.c Douglas Anderson
2023-05-23 11:45   ` Petr Mladek
2023-05-19 17:18 ` Douglas Anderson [this message]
2023-05-19 17:18 ` [PATCH v5 10/18] watchdog/hardlockup: Add a "cpu" param to watchdog_hardlockup_check() Douglas Anderson
2023-05-23 16:02   ` Petr Mladek
2023-05-23 16:34     ` Doug Anderson
2023-05-24 11:36       ` Petr Mladek
2023-05-19 17:18 ` [PATCH v5 11/18] watchdog/hardlockup: Move perf hardlockup watchdog petting to watchdog.c Douglas Anderson
2023-05-24 13:07   ` Petr Mladek
2023-05-19 17:18 ` [PATCH v5 12/18] watchdog/hardlockup: Rename some "NMI watchdog" constants/function Douglas Anderson
2023-05-24 13:38   ` Petr Mladek
2023-05-25 23:33     ` Doug Anderson
2023-05-19 17:18 ` [PATCH v5 13/18] watchdog/hardlockup: Have the perf hardlockup use __weak functions more cleanly Douglas Anderson
2023-05-24 13:59   ` Petr Mladek
2023-05-24 19:38     ` Doug Anderson
2023-05-26 14:44       ` Petr Mladek
2023-05-19 17:18 ` [PATCH v5 14/18] watchdog/hardlockup: detect hard lockups using secondary (buddy) CPUs Douglas Anderson
2023-05-25 16:26   ` Petr Mladek
2023-05-25 20:08     ` Doug Anderson
2023-05-26 12:29       ` Petr Mladek
2023-05-19 17:18 ` [PATCH v5 15/18] watchdog/perf: Add a weak function for an arch to detect if perf can use NMIs Douglas Anderson
2023-05-26 12:36   ` Petr Mladek
2023-06-12 10:33   ` Mark Rutland
2023-06-12 13:55     ` Doug Anderson
2023-06-12 13:59       ` Mark Rutland
2023-05-19 17:18 ` [PATCH v5 16/18] watchdog/perf: Adapt the watchdog_perf interface for async model Douglas Anderson
2023-05-19 17:18 ` [PATCH v5 17/18] arm64: add hw_nmi_get_sample_period for preparation of lockup detector Douglas Anderson
2023-05-19 17:18 ` [PATCH v5 18/18] arm64: Enable perf events based hard " Douglas Anderson

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