Messages in this thread | | | From | Pingfan Liu <> | Subject | [PATCHv2 0/4] watchdog_hld cleanup and async model for arm64 | Date | Thu, 23 Sep 2021 22:09:47 +0800 |
| |
hard lockup detector is helpful to diagnose unpaired irq enable/disable. Sumit has tried with a series, and the last one is V5 [1]. Since it lasts a long time without any update, I takes a retry, which addresses the delay intialization of watchdog_hld. ( To: Sumit, I think the main body of [4/4] is contributed from you,so I keep you as the author, please let me know if you dislike it and my modification.)
There is an obstacle to integrate arm64 hw perf event into watchdog_hld. When lockup_detector_init()->watchdog_nmi_probe(), on arm64, 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.
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. [1]: http://lore.kernel.org/linux-arm-kernel/1610712101-14929-1-git-send-email-sumit.garg@linaro.org
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: clarify the condition in hardlockup_detector_event_create() 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 +++++++++++++++++++++++++++ drivers/perf/arm_pmu.c | 5 ++++ include/linux/nmi.h | 5 +++- include/linux/perf/arm_pmu.h | 2 ++ kernel/watchdog.c | 42 +++++++++++++++++++++++++++----- kernel/watchdog_hld.c | 5 +++- 9 files changed, 99 insertions(+), 10 deletions(-) create mode 100644 arch/arm64/kernel/watchdog_hld.c
-- 2.31.1
| |