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3dc6ffae2d
linux/kernel
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Kurt Kanzenbach 3dc6ffae2d timekeeping: Introduce fast accessor to clock tai 
Introduce fast/NMI safe accessor to clock tai for tracing. The Linux kernel
tracing infrastructure has support for using different clocks to generate
timestamps for trace events. Especially in TSN networks it's useful to have TAI
as trace clock, because the application scheduling is done in accordance to the
network time, which is based on TAI. With a tai trace_clock in place, it becomes
very convenient to correlate network activity with Linux kernel application
traces.

Use the same implementation as ktime_get_boot_fast_ns() does by reading the
monotonic time and adding the TAI offset. The same limitations as for the fast
boot implementation apply. The TAI offset may change at run time e.g., by
setting the time or using adjtimex() with an offset. However, these kind of
offset changes are rare events. Nevertheless, the user has to be aware and deal
with it in post processing.

An alternative approach would be to use the same implementation as
ktime_get_real_fast_ns() does. However, this requires to add an additional u64
member to the tk_read_base struct. This struct together with a seqcount is
designed to fit into a single cache line on 64 bit architectures. Adding a new
member would violate this constraint.

Signed-off-by: Kurt Kanzenbach <kurt@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: https://lore.kernel.org/r/20220414091805.89667-2-kurt@linutronix.de
2022-04-14 16:19:30 +02:00
..
bpf bpf: Fix maximum permitted number of arguments check 2022-03-28 19:08:17 -07:00
cgroup Driver core changes for 5.18-rc1 2022-03-28 12:41:28 -07:00
configs Char/Misc and other driver updates for 5.18-rc1 2022-03-28 12:27:35 -07:00
debug kdb: Fix the putarea helper function 2022-03-24 16:39:47 +00:00
dma dma-mapping: move pgprot_decrypted out of dma_pgprot 2022-04-01 06:46:51 +02:00
entry entry: Fix compile error in dynamic_irqentry_exit_cond_resched() 2022-04-05 09:59:36 +02:00
events perf/core: Always set cpuctx cgrp when enable cgroup event 2022-04-05 09:59:45 +02:00
futex mm/truncate: Inline invalidate_complete_page() into its one caller 2022-03-21 12:59:01 -04:00
gcov gcov: Remove compiler version check 2021-12-02 17:25:21 +09:00
irq Changes in this cycle were: 2022-03-22 14:39:12 -07:00
kcsan KCSAN updates for v5.17 2022-01-11 09:51:26 -08:00
livepatch ptrace: Cleanups for v5.18 2022-03-28 17:29:53 -07:00
locking Changes in this cycle were: 2022-03-22 13:44:21 -07:00
power for-5.18/block-2022-03-18 2022-03-21 16:48:55 -07:00
printk printk changes for 5.18 2022-03-23 10:54:27 -07:00
rcu Changes in this cycle were: 2022-03-22 14:39:12 -07:00
sched sched: Teach the forced-newidle balancer about CPU affinity limitation. 2022-04-05 09:59:36 +02:00
time timekeeping: Introduce fast accessor to clock tai 2022-04-14 16:19:30 +02:00
trace Networking fixes for 5.18-rc2, including fixes from bpf and netfilter 2022-04-07 19:01:47 -10:00
.gitignore
acct.c kernel: remove spurious blkdev.h includes 2021-10-18 06:17:01 -06:00
async.c Revert "module, async: async_synchronize_full() on module init iff async is used" 2022-02-03 11:20:34 -08:00
audit_fsnotify.c fsnotify: clarify contract for create event hooks 2021-10-27 12:32:34 +02:00
audit_tree.c audit: use struct_size() helper in kmalloc() 2021-12-14 17:39:42 -05:00
audit_watch.c \n 2021-11-06 16:43:20 -07:00
audit.c audit: improve audit queue handling when "audit=1" on cmdline 2022-01-25 13:22:51 -05:00
audit.h audit: log AUDIT_TIME_* records only from rules 2022-02-22 13:51:40 -05:00
auditfilter.c audit/stable-5.17 PR 20220110 2022-01-11 13:08:21 -08:00
auditsc.c audit/stable-5.18 PR 20220321 2022-03-21 20:53:11 -07:00
backtracetest.c
bounds.c
capability.c xfs: don't generate selinux audit messages for capability testing 2022-03-09 10:32:06 -08:00
cfi.c cfi: Use rcu_read_{un}lock_sched_notrace 2021-08-11 13:11:12 -07:00
compat.c arch: remove compat_alloc_user_space 2021-09-08 15:32:35 -07:00
configs.c
context_tracking.c
cpu_pm.c PM: cpu: Make notifier chain use a raw_spinlock_t 2021-08-16 18:55:32 +02:00
cpu.c Changes in this cycle were: 2022-03-22 14:39:12 -07:00
crash_core.c kernel/crash_core: suppress unknown crashkernel parameter warning 2021-12-25 12:20:55 -08:00
crash_dump.c
cred.c x86: Mark __invalid_creds() __noreturn 2022-03-15 10:32:44 +01:00
delayacct.c delayacct: track delays from memory compact 2022-01-20 08:52:55 +02:00
dma.c
exec_domain.c
exit.c ptrace: Cleanups for v5.18 2022-03-28 17:29:53 -07:00
extable.c lkdtm: Really write into kernel text in WRITE_KERN 2022-02-16 23:25:12 +11:00
fail_function.c
fork.c kasan, arm64: reset pointer tags of vmapped stacks 2022-03-24 19:06:47 -07:00
freezer.c sched: Add get_current_state() 2021-06-18 11:43:08 +02:00
gen_kheaders.sh kbuild: clean up ${quiet} checks in shell scripts 2021-05-27 04:01:50 +09:00
groups.c
hung_task.c hung_task: move hung_task sysctl interface to hung_task.c 2022-01-22 08:33:34 +02:00
iomem.c
irq_work.c irq_work: Also rcuwait for !IRQ_WORK_HARD_IRQ on PREEMPT_RT 2021-10-15 11:25:18 +02:00
jump_label.c jump_label: Fix jump_label_text_reserved() vs __init 2021-07-05 10:46:20 +02:00
kallsyms.c kallsyms: Skip the name search for empty string 2022-03-17 20:17:18 -07:00
kcmp.c
Kconfig.freezer
Kconfig.hz
Kconfig.locks locking/rwlock: Provide RT variant 2021-08-17 17:50:51 +02:00
Kconfig.preempt Revert "signal, x86: Delay calling signals in atomic on RT enabled kernels" 2022-03-31 10:36:55 +02:00
kcov.c kcov: properly handle subsequent mmap calls 2022-03-23 19:00:35 -07:00
kexec_core.c exit: Move oops specific logic from do_exit into make_task_dead 2021-12-13 12:04:45 -06:00
kexec_elf.c
kexec_file.c memblock: add MEMBLOCK_DRIVER_MANAGED to mimic IORESOURCE_SYSRAM_DRIVER_MANAGED 2021-11-06 13:30:42 -07:00
kexec_internal.h
kexec.c kexec: avoid compat_alloc_user_space 2021-09-08 15:32:34 -07:00
kheaders.c
kmod.c
kprobes.c kprobes: Use rethook for kretprobe if possible 2022-03-28 19:38:09 -07:00
ksysfs.c kernel/ksysfs.c: use helper macro __ATTR_RW 2022-03-23 19:00:33 -07:00
kthread.c asm-generic updates for 5.18 2022-03-23 18:03:08 -07:00
latencytop.c
Makefile static_call: Don't make __static_call_return0 static 2022-04-05 09:59:38 +02:00
module_decompress.c module: fix building with sysfs disabled 2022-02-16 12:51:32 -08:00
module_signature.c
module_signing.c
module-internal.h module: add in-kernel support for decompressing 2022-01-11 18:45:02 -08:00
module.c NFSD: Remove svc_serv_ops::svo_module 2022-02-28 10:26:40 -05:00
notifier.c notifier: Return an error when a callback has already been registered 2021-12-29 10:37:33 +01:00
nsproxy.c memcg: enable accounting for new namesapces and struct nsproxy 2021-09-03 09:58:12 -07:00
padata.c padata: replace cpumask_weight with cpumask_empty in padata.c 2022-01-31 11:21:46 +11:00
panic.c panic: move panic_print before kmsg dumpers 2022-03-23 19:00:35 -07:00
params.c kobject: remove kset from struct kset_uevent_ops callbacks 2021-12-28 11:26:18 +01:00
pid_namespace.c memcg: enable accounting for new namesapces and struct nsproxy 2021-09-03 09:58:12 -07:00
pid.c pid: add pidfd_get_task() helper 2021-10-14 13:29:18 +02:00
profile.c exit: Remove profile_handoff_task 2022-01-08 12:43:57 -06:00
ptrace.c ptrace: Check PTRACE_O_SUSPEND_SECCOMP permission on PTRACE_SEIZE 2022-03-22 13:06:05 -05:00
range.c
reboot.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input 2021-11-12 11:53:16 -08:00
regset.c
relay.c
resource_kunit.c
resource.c kernel/resource: fix kfree() of bootmem memory again 2022-03-23 19:00:35 -07:00
rseq.c rseq: Remove broken uapi field layout on 32-bit little endian 2022-02-02 13:11:34 +01:00
scftorture.c scftorture: Always log error message 2021-12-07 16:36:17 -08:00
scs.c kasan, vmalloc: only tag normal vmalloc allocations 2022-03-24 19:06:48 -07:00
seccomp.c ptrace: Cleanups for v5.18 2022-03-28 17:29:53 -07:00
signal.c Revert "signal, x86: Delay calling signals in atomic on RT enabled kernels" 2022-03-31 10:36:55 +02:00
smp.c sched: Improve wake_up_all_idle_cpus() take #2 2021-10-22 15:32:46 +02:00
smpboot.c smpboot: Replace deprecated CPU-hotplug functions. 2021-08-10 14:57:42 +02:00
smpboot.h
softirq.c genirq, softirq: Use in_hardirq() instead of in_irq() 2022-02-02 21:34:19 +01:00
stackleak.c gcc-plugins/stackleak: Use noinstr in favor of notrace 2022-02-03 17:02:21 -08:00
stacktrace.c uaccess: remove CONFIG_SET_FS 2022-02-25 09:36:06 +01:00
static_call_inline.c static_call: Don't make __static_call_return0 static 2022-04-05 09:59:38 +02:00
static_call.c static_call: Don't make __static_call_return0 static 2022-04-05 09:59:38 +02:00
stop_machine.c
sys_ni.c mm/mempolicy: wire up syscall set_mempolicy_home_node 2022-01-15 16:30:30 +02:00
sys.c prlimit: do not grab the tasklist_lock 2022-03-08 14:33:36 -06:00
sysctl-test.c kernel/sysctl-test: Remove some casts which are no-longer required 2021-06-23 16:41:24 -06:00
sysctl.c Merge branch 'akpm' (patches from Andrew) 2022-03-22 16:11:53 -07:00
task_work.c resume_user_mode: Move to resume_user_mode.h 2022-03-10 16:51:50 -06:00
taskstats.c taskstats: remove unneeded dead assignment 2022-03-23 19:00:35 -07:00
torture.c torture: Wake up kthreads after storing task_struct pointer 2022-02-01 17:24:39 -08:00
tracepoint.c tracepoint: Fix kerneldoc comments 2021-08-16 11:39:51 -04:00
tsacct.c taskstats: Cleanup the use of task->exit_code 2022-01-08 12:43:57 -06:00
ucount.c ucounts: Handle wrapping in is_ucounts_overlimit 2022-02-17 09:11:57 -06:00
uid16.c
uid16.h
umh.c
up.c
user_namespace.c ucounts: Fix systemd LimitNPROC with private users regression 2022-02-25 10:40:14 -06:00
user-return-notifier.c
user.c fs/epoll: use a per-cpu counter for user's watches count 2021-09-08 11:50:27 -07:00
usermode_driver.c Merge branch 'work.namei' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2021-07-03 11:41:14 -07:00
utsname_sysctl.c
utsname.c
watch_queue.c watch_queue: Free the page array when watch_queue is dismantled 2022-04-02 10:37:39 -07:00
watchdog_hld.c
watchdog.c sched/isolation: Use single feature type while referring to housekeeping cpumask 2022-02-16 15:57:55 +01:00
workqueue_internal.h workqueue: Assign a color to barrier work items 2021-08-17 07:49:10 -10:00
workqueue.c Merge branch 'for-5.18' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq 2022-03-23 12:40:51 -07:00