Messages in this thread | | | From | Pingfan Liu <> | Subject | [PATCHv3 0/4] watchdog_hld cleanup and async model for arm64 | Date | Thu, 14 Oct 2021 10:41:51 +0800 |
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Hard lockup detector is helpful to diagnose unpaired irq enable/disable. But the current watchdog framework can not cope with arm64 hw perf event easily.
On arm64, when lockup_detector_init()->watchdog_nmi_probe(), PMU is not ready until device_initcall(armv8_pmu_driver_init). And it is deeply integrated with the driver model and cpuhp. Hence it is hard to push the initialization of armv8_pmu_driver_init() before smp_init().
But it is easy to take an opposite approach by enabling watchdog_hld to get the capability of PMU async. The async model is achieved by expanding watchdog_nmi_probe() with -EBUSY, and a re-initializing work_struct which waits on a wait_queue_head.
In this series, [1-2/4] are trivial cleanup. [3-4/4] is for this async model.
v2 -> v3: check the delay work waken up and flush the work before __initdata is free. improve the commit log of [4/4] rebase to v5.15-rc5
v1 > v2: uplift the async model from hard lockup layer to watchdog layter. The benefit is simpler code, the drawback is re-initialize means wasted alloc/free. Cc: Sumit Garg <sumit.garg@linaro.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will@kernel.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Marc Zyngier <maz@kernel.org> Cc: Kees Cook <keescook@chromium.org> Cc: Masahiro Yamada <masahiroy@kernel.org> Cc: Sami Tolvanen <samitolvanen@google.com> Cc: Petr Mladek <pmladek@suse.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Wang Qing <wangqing@vivo.com> Cc: "Peter Zijlstra (Intel)" <peterz@infradead.org> Cc: Santosh Sivaraj <santosh@fossix.org> To: linux-arm-kernel@lists.infradead.org To: linux-kernel@vger.kernel.org
*** BLURB HERE ***
Pingfan Liu (3): kernel/watchdog: trival cleanups kernel/watchdog_hld: Ensure CPU-bound context when creating hardlockup detector event kernel/watchdog: Adapt the watchdog_hld interface for async model
Sumit Garg (1): arm64: Enable perf events based hard lockup detector
arch/arm64/Kconfig | 2 ++ arch/arm64/kernel/Makefile | 1 + arch/arm64/kernel/perf_event.c | 11 ++++-- arch/arm64/kernel/watchdog_hld.c | 36 +++++++++++++++++++ arch/sparc/kernel/nmi.c | 8 ++--- drivers/perf/arm_pmu.c | 5 +++ include/linux/nmi.h | 11 +++++- include/linux/perf/arm_pmu.h | 2 ++ kernel/watchdog.c | 62 ++++++++++++++++++++++++++++---- kernel/watchdog_hld.c | 5 ++- 10 files changed, 129 insertions(+), 14 deletions(-) create mode 100644 arch/arm64/kernel/watchdog_hld.c
-- 2.31.1
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