summaryrefslogtreecommitdiff
path: root/lib
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@linux-foundation.org>2024-11-19 16:35:06 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2024-11-19 16:35:06 -0800
commitbf9aa14fc523d2763fc9a10672a709224e8fcaf4 (patch)
tree7d9c0cad473dc27a0c9bb09c561511df9481b066 /lib
parent035238752319a58244d86facd442c5f40b0e97e2 (diff)
parentcdc905d16b07981363e53a21853ba1cf6cd8e92a (diff)
Merge tag 'timers-core-2024-11-18' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timer updates from Thomas Gleixner: "A rather large update for timekeeping and timers: - The final step to get rid of auto-rearming posix-timers posix-timers are currently auto-rearmed by the kernel when the signal of the timer is ignored so that the timer signal can be delivered once the corresponding signal is unignored. This requires to throttle the timer to prevent a DoS by small intervals and keeps the system pointlessly out of low power states for no value. This is a long standing non-trivial problem due to the lock order of posix-timer lock and the sighand lock along with life time issues as the timer and the sigqueue have different life time rules. Cure this by: - Embedding the sigqueue into the timer struct to have the same life time rules. Aside of that this also avoids the lookup of the timer in the signal delivery and rearm path as it's just a always valid container_of() now. - Queuing ignored timer signals onto a seperate ignored list. - Moving queued timer signals onto the ignored list when the signal is switched to SIG_IGN before it could be delivered. - Walking the ignored list when SIG_IGN is lifted and requeue the signals to the actual signal lists. This allows the signal delivery code to rearm the timer. This also required to consolidate the signal delivery rules so they are consistent across all situations. With that all self test scenarios finally succeed. - Core infrastructure for VFS multigrain timestamping This is required to allow the kernel to use coarse grained time stamps by default and switch to fine grained time stamps when inode attributes are actively observed via getattr(). These changes have been provided to the VFS tree as well, so that the VFS specific infrastructure could be built on top. - Cleanup and consolidation of the sleep() infrastructure - Move all sleep and timeout functions into one file - Rework udelay() and ndelay() into proper documented inline functions and replace the hardcoded magic numbers by proper defines. - Rework the fsleep() implementation to take the reality of the timer wheel granularity on different HZ values into account. Right now the boundaries are hard coded time ranges which fail to provide the requested accuracy on different HZ settings. - Update documentation for all sleep/timeout related functions and fix up stale documentation links all over the place - Fixup a few usage sites - Rework of timekeeping and adjtimex(2) to prepare for multiple PTP clocks A system can have multiple PTP clocks which are participating in seperate and independent PTP clock domains. So far the kernel only considers the PTP clock which is based on CLOCK TAI relevant as that's the clock which drives the timekeeping adjustments via the various user space daemons through adjtimex(2). The non TAI based clock domains are accessible via the file descriptor based posix clocks, but their usability is very limited. They can't be accessed fast as they always go all the way out to the hardware and they cannot be utilized in the kernel itself. As Time Sensitive Networking (TSN) gains traction it is required to provide fast user and kernel space access to these clocks. The approach taken is to utilize the timekeeping and adjtimex(2) infrastructure to provide this access in a similar way how the kernel provides access to clock MONOTONIC, REALTIME etc. Instead of creating a duplicated infrastructure this rework converts timekeeping and adjtimex(2) into generic functionality which operates on pointers to data structures instead of using static variables. This allows to provide time accessors and adjtimex(2) functionality for the independent PTP clocks in a subsequent step. - Consolidate hrtimer initialization hrtimers are set up by initializing the data structure and then seperately setting the callback function for historical reasons. That's an extra unnecessary step and makes Rust support less straight forward than it should be. Provide a new set of hrtimer_setup*() functions and convert the core code and a few usage sites of the less frequently used interfaces over. The bulk of the htimer_init() to hrtimer_setup() conversion is already prepared and scheduled for the next merge window. - Drivers: - Ensure that the global timekeeping clocksource is utilizing the cluster 0 timer on MIPS multi-cluster systems. Otherwise CPUs on different clusters use their cluster specific clocksource which is not guaranteed to be synchronized with other clusters. - Mostly boring cleanups, fixes, improvements and code movement" * tag 'timers-core-2024-11-18' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (140 commits) posix-timers: Fix spurious warning on double enqueue versus do_exit() clocksource/drivers/arm_arch_timer: Use of_property_present() for non-boolean properties clocksource/drivers/gpx: Remove redundant casts clocksource/drivers/timer-ti-dm: Fix child node refcount handling dt-bindings: timer: actions,owl-timer: convert to YAML clocksource/drivers/ralink: Add Ralink System Tick Counter driver clocksource/drivers/mips-gic-timer: Always use cluster 0 counter as clocksource clocksource/drivers/timer-ti-dm: Don't fail probe if int not found clocksource/drivers:sp804: Make user selectable clocksource/drivers/dw_apb: Remove unused dw_apb_clockevent functions hrtimers: Delete hrtimer_init_on_stack() alarmtimer: Switch to use hrtimer_setup() and hrtimer_setup_on_stack() io_uring: Switch to use hrtimer_setup_on_stack() sched/idle: Switch to use hrtimer_setup_on_stack() hrtimers: Delete hrtimer_init_sleeper_on_stack() wait: Switch to use hrtimer_setup_sleeper_on_stack() timers: Switch to use hrtimer_setup_sleeper_on_stack() net: pktgen: Switch to use hrtimer_setup_sleeper_on_stack() futex: Switch to use hrtimer_setup_sleeper_on_stack() fs/aio: Switch to use hrtimer_setup_sleeper_on_stack() ...
Diffstat (limited to 'lib')
-rw-r--r--lib/Kconfig.debug13
1 files changed, 0 insertions, 13 deletions
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 188f3fd6bdd3..652ec5f5fdfb 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -1328,19 +1328,6 @@ config SCHEDSTATS
endmenu
-config DEBUG_TIMEKEEPING
- bool "Enable extra timekeeping sanity checking"
- help
- This option will enable additional timekeeping sanity checks
- which may be helpful when diagnosing issues where timekeeping
- problems are suspected.
-
- This may include checks in the timekeeping hotpaths, so this
- option may have a (very small) performance impact to some
- workloads.
-
- If unsure, say N.
-
config DEBUG_PREEMPT
bool "Debug preemptible kernel"
depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT