ZhenguoYao 95f091274f watchdog/softlockup: fix incorrect CPU utilization output during softlockup ... Since we use 16-bit precision, the raw data will undergo integer division, which may sometimes result in data loss. This can lead to slightly inaccurate CPU utilization calculations. Under normal circumstances, this isn't an issue. However, when CPU utilization reaches 100%, the calculated result might exceed 100%. For example, with raw data like the following: sample_period 400000134 new_stat 83648414036 old_stat 83247417494 sample_period=400000134/2^24=23 new_stat=83648414036/2^24=4985 old_stat=83247417494/2^24=4961 util=105% Below log will output： CPU#3 Utilization every 0s during lockup: #1: 0% system, 0% softirq, 105% hardirq, 0% idle #2: 0% system, 0% softirq, 105% hardirq, 0% idle #3: 0% system, 0% softirq, 100% hardirq, 0% idle #4: 0% system, 0% softirq, 105% hardirq, 0% idle #5: 0% system, 0% softirq, 105% hardirq, 0% idle To avoid confusion, we enforce a 100% display cap when calculations exceed this threshold. We also round to the nearest multiple of 16.8 milliseconds to improve the accuracy. [yaozhenguo1@gmail.com: make get_16bit_precision() more accurate, fix comment layout] Link: https://lkml.kernel.org/r/20250818081438.40540-1-yaozhenguo@jd.com Link: https://lkml.kernel.org/r/20250812082510.32291-1-yaozhenguo@jd.com Signed-off-by: ZhenguoYao <yaozhenguo1@gmail.com> Cc: Bitao Hu <yaoma@linux.alibaba.com> Cc: Li Huafei <lihuafei1@huawei.com> Cc: Max Kellermann <max.kellermann@ionos.com> Cc: Thomas Gleinxer <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>		2025-09-13 17:32:47 -07:00
..
bpf	bpf: Fix memory leak of bpf_scc_info objects	2025-08-02 09:04:57 -07:00
cgroup	cgroup: avoid null de-ref in css_rstat_exit()	2025-08-09 08:46:32 -10:00
configs	configs/hardening: Enable CONFIG_INIT_ON_FREE_DEFAULT_ON	2025-07-21 21:41:57 -07:00
debug	…
dma	dma/pool: Ensure DMA_DIRECT_REMAP allocations are decrypted	2025-08-13 11:02:10 +02:00
entry	ARM:	2025-07-30 17:14:01 -07:00
events	perf: Avoid undefined behavior from stopping/starting inactive events	2025-08-15 13:12:56 +02:00
futex	futex: Use user_write_access_begin/_end() in futex_put_value()	2025-08-11 17:53:21 +02:00
gcov	kbuild: require gcc-8 and binutils-2.30	2025-04-30 21:53:35 +02:00
irq	genirq/test: Resolve irq lock inversion warnings	2025-08-06 10:29:48 +02:00
kcsan	kcsan: test: Initialize dummy variable	2025-07-23 08:51:32 +02:00
livepatch	sched,livepatch: Untangle cond_resched() and live-patching	2025-05-14 13:16:24 +02:00
locking	- Make sure sanity checks down in the mutex lock path happen on the correct	2025-08-17 05:57:47 -07:00
module	Significant patch series in this pull request:	2025-08-05 16:02:07 +03:00
power	drm for 6.17-rc1	2025-07-30 19:26:49 -07:00
printk	printk changes for 6.17	2025-08-04 10:54:36 -07:00
rcu	rcu: Fix racy re-initialization of irq_work causing hangs	2025-08-11 08:43:49 +05:30
sched	sched/deadline: Don't count nr_running for dl_server proxy tasks	2025-08-26 10:46:01 +02:00
time	bitmap-for-6.17	2025-07-31 16:52:32 -07:00
trace	tracing fixes for v6.17-rc2:	2025-08-23 10:11:34 -04:00
unwind	unwind: Finish up unwind when a task exits	2025-07-31 10:20:11 -04:00
.gitignore	kheaders: rebuild kheaders_data.tar.xz when a file is modified within a minute	2025-06-24 20:30:37 +09:00
Kconfig.freezer	…
Kconfig.hz	…
Kconfig.kexec	kho: mm: don't allow deferred struct page with KHO	2025-08-19 16:35:53 -07:00
Kconfig.locks	…
Kconfig.preempt	…
Makefile	Kbuild updates for v6.17	2025-08-06 07:32:52 +03:00
acct.c	…
async.c	…
audit.c	…
audit.h	audit,module: restore audit logging in load failure case	2025-06-16 17:00:06 -04:00
audit_fsnotify.c	…
audit_tree.c	replace collect_mounts()/drop_collected_mounts() with a safer variant	2025-06-23 14:01:49 -04:00
audit_watch.c	fs: add kern_path_locked_negative()	2025-04-15 11:32:34 +02:00
auditfilter.c	…
auditsc.c	audit,module: restore audit logging in load failure case	2025-06-16 17:00:06 -04:00
backtracetest.c	…
bounds.c	…
capability.c	…
cfi.c	cfi: Move BPF CFI types and helpers to generic code	2025-07-31 18:23:53 -07:00
compat.c	…
configs.c	…
context_tracking.c	…
cpu.c	cpu: Remove obsolete comment from takedown_cpu()	2025-08-06 22:48:12 +02:00
cpu_pm.c	…
crash_core.c	kdump: wait for DMA to finish when using CMA	2025-07-19 19:08:23 -07:00
crash_dump_dm_crypt.c	crash_dump: retrieve dm crypt keys in kdump kernel	2025-05-21 10:48:21 -07:00
crash_reserve.c	kdump: implement reserve_crashkernel_cma	2025-07-19 19:08:23 -07:00
cred.c	…
delayacct.c	delayacct: remove redundant code and adjust indentation	2025-05-27 19:40:33 -07:00
dma.c	…
elfcorehdr.c	…
exec_domain.c	…
exit.c	Significant patch series in this pull request:	2025-08-03 16:23:09 -07:00
exit.h	…
extable.c	…
fail_function.c	…
fork.c	- Prevent a futex hash leak due to different mm lifetimes	2025-08-10 08:11:39 +03:00
freezer.c	sched,freezer: Remove unnecessary warning in __thaw_task	2025-07-17 07:56:50 -10:00
gen_kheaders.sh	kheaders: make it possible to override TAR	2025-08-06 10:23:36 +09:00
groups.c	…
hung_task.c	hung_task: dump blocker task if it is not hung	2025-09-13 17:32:43 -07:00
iomem.c	…
irq_work.c	…
jump_label.c	…
kallsyms.c	bpf: Clean up individual BTF_ID code	2025-07-16 18:34:42 -07:00
kallsyms_internal.h	…
kallsyms_selftest.c	…
kallsyms_selftest.h	…
kcmp.c	…
kcov.c	kcov: use write memory barrier after memcpy() in kcov_move_area()	2025-09-13 17:32:44 -07:00
kexec.c	kexec: enable CMA based contiguous allocation	2025-08-02 12:01:38 -07:00
kexec_core.c	Significant patch series in this pull request:	2025-08-03 16:23:09 -07:00
kexec_elf.c	…
kexec_file.c	x86/kexec: carry forward the boot DTB on kexec	2025-09-13 17:32:43 -07:00
kexec_handover.c	kho: warn if KHO is disabled due to an error	2025-08-19 16:35:53 -07:00
kexec_internal.h	kexec: enable CMA based contiguous allocation	2025-08-02 12:01:38 -07:00
kheaders.c	…
kprobes.c	kprobes: Add missing kerneldoc for __get_insn_slot	2025-07-15 18:45:34 +09:00
kstack_erase.c	stackleak: Rename stackleak_track_stack to __sanitizer_cov_stack_depth	2025-07-21 21:40:39 -07:00
ksyms_common.c	…
ksysfs.c	…
kthread.c	ipvs: Fix estimator kthreads preferred affinity	2025-08-13 08:34:33 +02:00
latencytop.c	…
module_signature.c	…
notifier.c	…
nsproxy.c	kernel/nsproxy: remove unnecessary guards	2025-05-09 13:13:54 +02:00
padata.c	padata: use cpumask_nth()	2025-06-13 17:26:17 +08:00
panic.c	Significant patch series in this pull request:	2025-08-03 16:23:09 -07:00
params.c	params: Replace deprecated strcpy() with strscpy() and memcpy()	2025-08-16 21:47:25 +02:00
pid.c	Summary	2025-07-29 21:43:08 -07:00
pid_namespace.c	…
pid_sysctl.h	…
profile.c	…
ptrace.c	ptrace: introduce PTRACE_SET_SYSCALL_INFO request	2025-05-11 17:48:15 -07:00
range.c	…
reboot.c	…
regset.c	…
relay.c	relayfs: support a counter tracking if data is too big to write	2025-07-09 22:57:52 -07:00
resource.c	resource: fix false warning in __request_region()	2025-07-24 17:57:59 -07:00
resource_kunit.c	…
rseq.c	…
scftorture.c	…
scs.c	…
seccomp.c	…
signal.c	signal: Fix memory leak for PIDFD_SELF* sentinels	2025-08-19 13:51:28 +02:00
smp.c	smp: Fix spelling in on_each_cpu_cond_mask()'s doc-comment	2025-08-02 14:24:50 +02:00
smpboot.c	sched/smp: Use the SMP version of idle_thread_set_boot_cpu()	2025-06-13 08:47:20 +02:00
smpboot.h	…
softirq.c	…
stacktrace.c	…
static_call.c	…
static_call_inline.c	…
stop_machine.c	sched/core: Fix migrate_swap() vs. hotplug	2025-07-01 15:02:03 +02:00
sys.c	Summary of significant series in this pull request:	2025-07-31 14:57:54 -07:00
sys_ni.c	…
sysctl-test.c	sysctl: move u8 register test to lib/test_sysctl.c	2025-04-14 14:13:41 +02:00
sysctl.c	sysctl: rename kern_table -> sysctl_subsys_table	2025-07-23 11:56:02 +02:00
task_work.c	…
taskstats.c	…
torture.c	…
tracepoint.c	…
tsacct.c	…
ucount.c	ucount: use atomic_long_try_cmpxchg() in atomic_long_inc_below()	2025-08-02 12:01:38 -07:00
uid16.c	…
uid16.h	…
umh.c	…
up.c	…
user-return-notifier.c	…
user.c	…
user_namespace.c	…
utsname.c	…
utsname_sysctl.c	…
vhost_task.c	vhost: Use ERR_CAST inlined function instead of ERR_PTR(PTR_ERR(...))	2025-08-01 09:11:08 -04:00
vmcore_info.c	crash: export PAGE_UNACCEPTED_MAPCOUNT_VALUE to vmcoreinfo	2025-05-11 17:54:04 -07:00
watch_queue.c	…
watchdog.c	watchdog/softlockup: fix incorrect CPU utilization output during softlockup	2025-09-13 17:32:47 -07:00
watchdog_buddy.c	watchdog: fix opencoded cpumask_next_wrap() in watchdog_next_cpu()	2025-07-31 11:28:03 -04:00
watchdog_perf.c	watchdog/perf: Provide function for adjusting the event period	2025-07-04 13:17:30 +01:00
workqueue.c	workqueue: Changes for v6.17	2025-07-31 15:40:22 -07:00
workqueue_internal.h	…