Messages in this thread | | | From | Tony Luck <> | Subject | [PATCH v4 0/5] Handle corrected machine check interrupt storms | Date | Mon, 3 Apr 2023 14:07:11 -0700 |
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Linux CMCI storm mitigation is a big hammer that just disables the CMCI interrupt globally and switches to polling all banks.
There are two problems with this: 1) It really is a big hammer. It means that errors reported in other banks from different functional units are all subject to the same polling delay before being processed. 2) Intel systems signal some uncorrected errors using CMCI (e.g. memory controller patrol scrub on Icelake Xeon and newer). Delaying processing these error reports negates some of the benefit of the patrol scrubber providing early notice of errors before they are consumed and cause a machine check.
This series throws away the old storm implementation and replaces it with one that keeps track of the weather on each separate machine check bank. When a storm is detected from a bank. On Intel the storm is mitigated by setting a very high threshold for corrected errors to signal CMCI. This threshold does not affect signaling CMCI for uncorrected errors.
AMD's storm mitigation for threshold interrupts also relies on per CPU per bank approach similar to Intel. But unlike CMCI storm handling it does not set thresholds to reduce rate of interrupts on a storm. Rather it turns off the interrupt on the current CPU and bank if there is a storm and re-enables back the interrupts when the storm subsides.
It is okay to turn off threshold interrupts on AMD systems as other error severities continue to be handled even if the threshold interrupts are turned off. Uncorrected errors will generate a #MC and deferred errors have a unique separate deferred error interrupt. The final patch adds support for handling threshold interrupt storms on AMD systems.
Changes since last version:
Yazen: Reported inverted tests in two places that cancelled each other out so the code worked. But the logic was backwards. Provided Tested-by and Reviewed-by tags
Smita Koralahalli (3): x86/mce: Introduce mce_handle_storm() to deal with begin/end of storms x86/mce: Move storm handling to core. x86/mce: Handle AMD threshold interrupt storms
Tony Luck (2): x86/mce: Remove old CMCI storm mitigation code x86/mce: Add per-bank CMCI storm mitigation
arch/x86/kernel/cpu/mce/internal.h | 33 ++++-- arch/x86/kernel/cpu/mce/amd.c | 49 ++++++++ arch/x86/kernel/cpu/mce/core.c | 139 +++++++++++++++++----- arch/x86/kernel/cpu/mce/intel.c | 179 +++++++---------------------- 4 files changed, 230 insertions(+), 170 deletions(-)
base-commit: 7e364e56293bb98cae1b55fd835f5991c4e96e7d -- 2.39.2
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