linux/include
Mayank Rungta 077ba03600 watchdog/hardlockup: improve buddy system detection timeliness
Currently, the buddy system only performs checks every 3rd sample.  With a
4-second interval.  If a check window is missed, the next check occurs 12
seconds later, potentially delaying hard lockup detection for up to 24
seconds.

Modify the buddy system to perform checks at every interval (4s). 
Introduce a missed-interrupt threshold to maintain the existing grace
period while reducing the detection window to 8-12 seconds.

Best and worst case detection scenarios:

Before (12s check window):
- Best case: Lockup occurs after first check but just before heartbeat
  interval. Detected in ~8s (8s till next check).
- Worst case: Lockup occurs just after a check.
  Detected in ~24s (missed check + 12s till next check + 12s logic).

After (4s check window with threshold of 3):
- Best case: Lockup occurs just before a check.
  Detected in ~8s (0s till 1st check + 4s till 2nd + 4s till 3rd).
- Worst case: Lockup occurs just after a check.
  Detected in ~12s (4s till 1st check + 4s till 2nd + 4s till 3rd).

Link: https://lkml.kernel.org/r/20260312-hardlockup-watchdog-fixes-v2-4-45bd8a0cc7ed@google.com
Signed-off-by: Mayank Rungta <mrungta@google.com>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Li Huafei <lihuafei1@huawei.com>
Cc: Max Kellermann <max.kellermann@ionos.com>
Cc: Shuah Khan <skhan@linuxfoundation.org>
Cc: Stephane Erainan <eranian@google.com>
Cc: Wang Jinchao <wangjinchao600@gmail.com>
Cc: Yunhui Cui <cuiyunhui@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-03-27 21:19:47 -07:00
..
acpi mailbox: platform and core updates 2026-02-14 11:13:32 -08:00
asm-generic kbuild: Split .modinfo out from ELF_DETAILS 2026-02-26 11:50:19 -07:00
clocksource
crypto Networking changes for 7.0 2026-02-11 19:31:52 -08:00
cxl
drm drm/dp: Add definition for Panel Replay full-line granularity 2026-03-04 15:26:08 +02:00
dt-bindings phy-for-7.0 2026-02-17 11:40:04 -08:00
hyperv Revert "mshv: expose the scrub partition hypercall" 2026-03-11 16:54:24 +00:00
keys
kunit kunit: irq: Ensure timer doesn't fire too frequently 2026-02-24 14:44:21 -08:00
kvm
linux watchdog/hardlockup: improve buddy system detection timeliness 2026-03-27 21:19:47 -07:00
math-emu
media [GIT PULL for v7.0] media updates 2026-02-11 12:20:25 -08:00
memory
misc
net Just a few updates: 2026-03-18 19:25:41 -07:00
pcmcia
ras
rdma RDMA/core: Check id_priv->restricted_node_type in cma_listen_on_dev() 2026-02-25 07:50:10 -05:00
rv rv: Fix multiple definition of __pcpu_unique_da_mon_this 2026-02-20 13:12:00 +01:00
scsi SCSI misc on 20260212 2026-02-12 15:43:02 -08:00
soc
sound ASoC: Fixes for v7.0 2026-03-05 17:22:14 +01:00
target
trace tracing: Revert "tracing: Remove pid in task_rename tracing output" 2026-03-21 16:41:18 -04:00
uapi ARM: 2026-03-15 12:22:10 -07:00
ufs
vdso
video
xen xen/xenbus: better handle backend crash 2026-03-04 15:31:40 +01:00
Kbuild