mbox series

[v8,0/3] Handle corrected machine check interrupt storms

Message ID 20230929181626.210782-1-tony.luck@intel.com
Headers
Series Handle corrected machine check interrupt storms |

Message

Luck, Tony Sept. 29, 2023, 6:16 p.m. UTC 
  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.

Signed-off-by: Tony Luck <tony.luck@intel.com>

---

Changes since v7:

Applied all the suggestions from Yazen's review of v7

Link: https://lore.kernel.org/all/c76723df-f2f1-4888-9e05-61917145503c@amd.com/
Link: https://lore.kernel.org/all/6ae4df67-ba0b-4b50-8c1d-a5d382105ad2@amd.com/

Including placing most of the storm tracking code into threshold.c
instead of bloating core.c.

Tony Luck (3):
  x86/mce: Remove old CMCI storm mitigation code
  x86/mce: Add per-bank CMCI storm mitigation
  x86/mce: Handle Intel threshold interrupt storms

 arch/x86/kernel/cpu/mce/internal.h  |  47 +++-
 arch/x86/kernel/cpu/mce/core.c      |  45 ++--
 arch/x86/kernel/cpu/mce/intel.c     | 338 ++++++++++++----------------
 arch/x86/kernel/cpu/mce/threshold.c |  86 +++++++
 4 files changed, 293 insertions(+), 223 deletions(-)


base-commit: 6465e260f48790807eef06b583b38ca9789b6072

Comments

Luck, Tony Oct. 2, 2023, 5:57 p.m. UTC | #1 
> Including placing most of the storm tracking code into threshold.c
> instead of bloating core.c.

The lkp test robot complains on a randconfig build with:

# CONFIG_X86_MCE_INTEL is not set
# CONFIG_X86_MCE_AMD is not set

about some undefined symbols. 

>> core.c:(.text+0x1130): undefined reference to `storm_desc'
>> core.c:(.text+0x1634): undefined reference to `mce_track_storm'

Simple fix would be to move definition of storm_desc into core.c
and provide a stub:

static inline void mce_track_storm(struct mce *mce) { }

for the case where neither INTEL nor AMD is configured.

in internal.h

-Tony