Changes in Kconfig

0fc8f6200d2313278fbf4539bbab74677c685531 - Merge drm/drm-fixes into drm-misc-fixes

Mon, 27 Apr 2026 10:26:49 +0200

Merge drm/drm-fixes into drm-misc-fixesGetting fixes and updates from v7.1-rc1.Signed-off-by: Thomas Zimmermann List of files: /linux/kernel/time/Kconfig

f21f7b5162e9dbde6d3d5ce727d4ca2552d76ce9 - Merge tag 'timers-vdso-2026-04-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Tue, 14 Apr 2026 19:53:44 +0200

Merge tag 'timers-vdso-2026-04-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tipPull vdso updates from Thomas Gleixner: - Make the handling of compat functions consistent and more robust - Rework the underlying data store so that it is dynamically allocated, which allows the conversion of the last holdout SPARC64 to the generic VDSO implementation - Rework the SPARC64 VDSO to utilize the generic implementation - Mop up the left overs of the non-generic VDSO support in the core code - Expand the VDSO selftest and make them more robust - Allow time namespaces to be enabled independently of the generic VDSO support, which was not possible before due to SPARC64 not using it - Various cleanups and improvements in the related code* tag 'timers-vdso-2026-04-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (51 commits) timens: Use task_lock guard in timens_get*() timens: Use mutex guard in proc_timens_set_offset() timens: Simplify some calls to put_time_ns() timens: Add a __free() wrapper for put_time_ns() timens: Remove dependency on the vDSO vdso/timens: Move functions to new file selftests: vDSO: vdso_test_correctness: Add a test for time() selftests: vDSO: vdso_test_correctness: Use facilities from parse_vdso.c selftests: vDSO: vdso_test_correctness: Handle different tv_usec types selftests: vDSO: vdso_test_correctness: Drop SYS_getcpu fallbacks selftests: vDSO: vdso_test_gettimeofday: Remove nolibc checks Revert "selftests: vDSO: parse_vdso: Use UAPI headers instead of libc headers" random: vDSO: Remove ifdeffery random: vDSO: Trim vDSO includes vdso/datapage: Trim down unnecessary includes vdso/datapage: Remove inclusion of gettimeofday.h vdso/helpers: Explicitly include vdso/processor.h vdso/gettimeofday: Add explicit includes random: vDSO: Add explicit includes MIPS: vdso: Explicitly include asm/vdso/vdso.h ... List of files: /linux/kernel/time/Kconfig

c1fe867b5bf9c57ab7856486d342720e2b205eed - Merge tag 'timers-core-2026-04-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Tue, 14 Apr 2026 19:27:07 +0200

Merge tag 'timers-core-2026-04-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tipPull timer core updates from Thomas Gleixner: - A rework of the hrtimer subsystem to reduce the overhead for frequently armed timers, especially the hrtick scheduler timer: - Better timer locality decision - Simplification of the evaluation of the first expiry time by keeping track of the neighbor timers in the RB-tree by providing a RB-tree variant with neighbor links. That avoids walking the RB-tree on removal to find the next expiry time, but even more important allows to quickly evaluate whether a timer which is rearmed changes the position in the RB-tree with the modified expiry time or not. If not, the dequeue/enqueue sequence which both can end up in rebalancing can be completely avoided. - Deferred reprogramming of the underlying clock event device. This optimizes for the situation where a hrtimer callback sets the need resched bit. In that case the code attempts to defer the re-programming of the clock event device up to the point where the scheduler has picked the next task and has the next hrtick timer armed. In case that there is no immediate reschedule or soft interrupts have to be handled before reaching the reschedule point in the interrupt entry code the clock event is reprogrammed in one of those code paths to prevent that the timer becomes stale. - Support for clocksource coupled clockevents The TSC deadline timer is coupled to the TSC. The next event is programmed in TSC time. Currently this is done by converting the CLOCK_MONOTONIC based expiry value into a relative timeout, converting it into TSC ticks, reading the TSC adding the delta ticks and writing the deadline MSR. As the timekeeping core has the conversion factors for the TSC already, the whole back and forth conversion can be completely avoided. The timekeeping core calculates the reverse conversion factors from nanoseconds to TSC ticks and utilizes the base timestamps of TSC and CLOCK_MONOTONIC which are updated once per tick. This allows a direct conversion into the TSC deadline value without reading the time and as a bonus keeps the deadline conversion in sync with the TSC conversion factors, which are updated by adjtimex() on systems with NTP/PTP enabled. - Allow inlining of the clocksource read and clockevent write functions when they are tiny enough, e.g. on x86 RDTSC and WRMSR. With all those enhancements in place a hrtick enabled scheduler provides the same performance as without hrtick. But also other hrtimer users obviously benefit from these optimizations. - Robustness improvements and cleanups of historical sins in the hrtimer and timekeeping code. - Rewrite of the clocksource watchdog. The clocksource watchdog code has over time reached the state of an impenetrable maze of duct tape and staples. The original design, which was made in the context of systems far smaller than today, is based on the assumption that the to be monitored clocksource (TSC) can be trivially compared against a known to be stable clocksource (HPET/ACPI-PM timer). Over the years this rather naive approach turned out to have major flaws. Long delays between the watchdog invocations can cause wrap arounds of the reference clocksource. The access to the reference clocksource degrades on large multi-sockets systems dure to interconnect congestion. This has been addressed with various heuristics which degraded the accuracy of the watchdog to the point that it fails to detect actual TSC problems on older hardware which exposes slow inter CPU drifts due to firmware manipulating the TSC to hide SMI time. The rewrite addresses this by: - Restricting the validation against the reference clocksource to the boot CPU which is usually closest to the legacy block which contains the reference clocksource (HPET/ACPI-PM). - Do a round robin validation betwen the boot CPU and the other CPUs based only on the TSC with an algorithm similar to the TSC synchronization code during CPU hotplug. - Being more leniant versus remote timeouts - The usual tiny fixes, cleanups and enhancements all over the place* tag 'timers-core-2026-04-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (75 commits) alarmtimer: Access timerqueue node under lock in suspend hrtimer: Fix incorrect #endif comment for BITS_PER_LONG check posix-timers: Fix stale function name in comment timers: Get this_cpu once while clearing the idle state clocksource: Rewrite watchdog code completely clocksource: Don't use non-continuous clocksources as watchdog x86/tsc: Handle CLOCK_SOURCE_VALID_FOR_HRES correctly MIPS: Don't select CLOCKSOURCE_WATCHDOG parisc: Remove unused clocksource flags hrtimer: Add a helper to retrieve a hrtimer from its timerqueue node hrtimer: Remove trailing comma after HRTIMER_MAX_CLOCK_BASES hrtimer: Mark index and clockid of clock base as const hrtimer: Drop unnecessary pointer indirection in hrtimer_expire_entry event hrtimer: Drop spurious space in 'enum hrtimer_base_type' hrtimer: Don't zero-initialize ret in hrtimer_nanosleep() hrtimer: Remove hrtimer_get_expires_ns() timekeeping: Mark offsets array as const timekeeping/auxclock: Consistently use raw timekeeper for tk_setup_internals() timer_list: Print offset as signed integer tracing: Use explicit array size instead of sentinel elements in symbol printing ... List of files: /linux/kernel/time/Kconfig

763aacf86f1baefb134c70813aa8c72d1675d738 - clocksource: Rewrite watchdog code completely

Tue, 17 Mar 2026 10:01:54 +0100

clocksource: Rewrite watchdog code completelyThe clocksource watchdog code has over time reached the state of animpenetrable maze of duct tape and staples. The original design, which wasmade in the context of systems far smaller than today, is based on theassumption that the to be monitored clocksource (TSC) can be triviallycompared against a known to be stable clocksource (HPET/ACPI-PM timer).Over the years it turned out that this approach has major flaws: - Long delays between watchdog invocations can result in wrap arounds of the reference clocksource - Scalability of the reference clocksource readout can degrade on large multi-socket systems due to interconnect congestionThis was addressed with various heuristics which degraded the accuracy ofthe watchdog to the point that it fails to detect actual TSC problems onolder hardware which exposes slow inter CPU drifts due to firmwaremanipulating the TSC to hide SMI time.To address this and bring back sanity to the watchdog, rewrite the codecompletely with a different approach: 1) Restrict the validation against a reference clocksource to the boot CPU, which is usually the CPU/Socket closest to the legacy block which contains the reference source (HPET/ACPI-PM timer). Validate that the reference readout is within a bound latency so that the actual comparison against the TSC stays within 500ppm as long as the clocks are stable. 2) Compare the TSCs of the other CPUs in a round robin fashion against the boot CPU in the same way the TSC synchronization on CPU hotplug works. This still can suffer from delayed reaction of the remote CPU to the SMP function call and the latency of the control variable cache line. But this latency is not affecting correctness. It only affects the accuracy. With low contention the readout latency is in the low nanoseconds range, which detects even slight skews between CPUs. Under high contention this becomes obviously less accurate, but still detects slow skews reliably as it solely relies on subsequent readouts being monotonically increasing. It just can take slightly longer to detect the issue. 3) Rewrite the watchdog test so it tests the various mechanisms one by one and validating the result against the expectation.Signed-off-by: Thomas Gleixner Tested-by: Borislav Petkov (AMD) Tested-by: Daniel J Blueman Reviewed-by: Jiri Wiesner Reviewed-by: Daniel J Blueman Link: https://patch.msgid.link/20260123231521.926490888@kernel.orgLink: https://patch.msgid.link/87h5qeomm5.ffs@tglx List of files: /linux/kernel/time/Kconfig

1e4a70e0f64f8362653e81ad6a32c508b555dd23 - Merge branch 'sched/hrtick' into timers/core

Wed, 11 Mar 2026 21:14:32 +0100

Merge branch 'sched/hrtick' into timers/corePick up the hrtick related hrtimer changes so other unrelated changes canbe queued on top. List of files: /linux/kernel/time/Kconfig

c453b9abb4f422461c1493ef74d63af0961a2d30 - clocksource: Remove ARCH_CLOCKSOURCE_DATA

Wed, 04 Mar 2026 08:49:11 +0100

clocksource: Remove ARCH_CLOCKSOURCE_DATAAfter sparc64, there are no remaining users of ARCH_CLOCKSOURCE_DATAand it can just be removed.Signed-off-by: Arnd Bergmann Signed-off-by: Thomas Weißschuh Signed-off-by: Thomas Gleixner Tested-by: Andreas Larsson Reviewed-by: Andreas Larsson Acked-by: John Stultz Link: https://patch.msgid.link/20260304-vdso-sparc64-generic-2-v6-14-d8eb3b0e1410@linutronix.de[Thomas: drop sparc64 bits from the patch] List of files: /linux/kernel/time/Kconfig

15dd3a9488557d3e6ebcecacab79f4e56b69ab54 - hrtimer: Push reprogramming timers into the interrupt return path

Tue, 24 Feb 2026 17:38:18 +0100

hrtimer: Push reprogramming timers into the interrupt return pathCurrently hrtimer_interrupt() runs expired timers, which can re-armthemselves, after which it computes the next expiration time andre-programs the hardware.However, things like HRTICK, a highres timer driving preemption, cannotre-arm itself at the point of running, since the next task has not beendetermined yet. The schedule() in the interrupt return path will switch tothe next task, which then causes a new hrtimer to be programmed.This then results in reprogramming the hardware at least twice, once afterrunning the timers, and once upon selecting the new task.Notably, *both* events happen in the interrupt.By pushing the hrtimer reprogram all the way into the interrupt returnpath, it runs after schedule() picks the new task and the double reprogramcan be avoided.Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Thomas Gleixner Signed-off-by: Peter Zijlstra (Intel) Link: https://patch.msgid.link/20260224163431.273488269@kernel.org List of files: /linux/kernel/time/Kconfig

a43b4856bc039675165a50d9ef5f41b28520f0f4 - hrtimer: Prepare stubs for deferred rearming

Tue, 24 Feb 2026 17:37:58 +0100

hrtimer: Prepare stubs for deferred rearmingThe hrtimer interrupt expires timers and at the end of the interrupt itrearms the clockevent device for the next expiring timer.That's obviously correct, but in the case that a expired timer setNEED_RESCHED the return from interrupt ends up in schedule(). If HRTICK isenabled then schedule() will modify the hrtick timer, which causes anotherreprogramming of the hardware.That can be avoided by deferring the rearming to the return from interruptpath and if the return results in a immediate schedule() invocation then itcan be deferred until the end of schedule().To make this correct the affected code parts need to be made aware of this.Provide empty stubs for the deferred rearming mechanism, so that therelevant code changes for entry, softirq and scheduler can be split up intoseparate changes independent of the actual enablement in the hrtimer code.Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Thomas Gleixner Signed-off-by: Peter Zijlstra (Intel) Link: https://patch.msgid.link/20260224163431.000891171@kernel.org List of files: /linux/kernel/time/Kconfig

89f951a1e8ad781e7ac70eccddab0e0c270485f9 - clockevents: Provide support for clocksource coupled comparators

Tue, 24 Feb 2026 17:36:45 +0100

clockevents: Provide support for clocksource coupled comparatorsSome clockevent devices are coupled to the system clocksource byimplementing a less than or equal comparator which compares the programmedabsolute expiry time against the underlying time counter.The timekeeping core provides a function to convert and absoluteCLOCK_MONOTONIC based expiry time to a absolute clock cycles time which canbe directly fed into the comparator. That spares two time reads in the nextevent progamming path, one to convert the absolute nanoseconds time to adelta value and the other to convert the delta value back to a absolutetime value suitable for the comparator.Provide a new clocksource callback which takes the absolute cycle value andwire it up in clockevents_program_event(). Similar to clocksources allowarchitectures to inline the rearm operation.Signed-off-by: Thomas Gleixner Signed-off-by: Peter Zijlstra (Intel) Link: https://patch.msgid.link/20260224163430.010425428@kernel.org List of files: /linux/kernel/time/Kconfig

cd38bdb8e696a1a1eb12fc6662a6e420977aacfd - timekeeping: Provide infrastructure for coupled clockevents

Tue, 24 Feb 2026 17:36:40 +0100

timekeeping: Provide infrastructure for coupled clockeventsSome architectures have clockevent devices which are coupled to the systemclocksource by implementing a less than or equal comparator which comparesthe programmed absolute expiry time against the underlying timecounter. Well known examples are TSC/TSC deadline timer and the S390 TODclocksource/comparator.While the concept is nice it has some downsides: 1) The clockevents core code is strictly based on relative expiry times as that's the most common case for clockevent device hardware. That requires to convert the absolute expiry time provided by the caller (hrtimers, NOHZ code) to a relative expiry time by reading and substracting the current time. The clockevent::set_next_event() callback must then read the counter again to convert the relative expiry back into a absolute one. 2) The conversion factors from nanoseconds to counter clock cycles are set up when the clockevent is registered. When NTP applies corrections then the clockevent conversion factors can deviate from the clocksource conversion substantially which either results in timers firing late or in the worst case early. The early expiry then needs to do a reprogam with a short delta. In most cases this is papered over by the fact that the read in the set_next_event() callback happens after the read which is used to calculate the delta. So the tendency is that timers expire mostly late.All of this can be avoided by providing support for these devices in thecore code: 1) The timekeeping core keeps track of the last update to the clocksource by storing the base nanoseconds and the corresponding clocksource counter value. That's used to keep the conversion math for reading the time within 64-bit in the common case. This information can be used to avoid both reads of the underlying clocksource in the clockevents reprogramming path: delta = expiry - base_ns; cycles = base_cycles + ((delta * clockevent::mult) >> clockevent::shift); The resulting cycles value can be directly used to program the comparator. 2) As #1 does not longer provide the "compensation" through the second read the deviation of the clocksource and clockevent conversions caused by NTP become more prominent. This can be cured by letting the timekeeping core compute and store the reverse conversion factors when the clocksource cycles to nanoseconds factors are modified by NTP: CS::MULT (1 << NS_TO_CYC_SHIFT) --------------- = ---------------------- (1 << CS:SHIFT) NS_TO_CYC_MULT Ergo: NS_TO_CYC_MULT = (1 << (CS::SHIFT + NS_TO_CYC_SHIFT)) / CS::MULT The NS_TO_CYC_SHIFT value is calculated when the clocksource is installed so that it aims for a one hour maximum sleep time.Signed-off-by: Thomas Gleixner Signed-off-by: Peter Zijlstra (Intel) Link: https://patch.msgid.link/20260224163429.944763521@kernel.org List of files: /linux/kernel/time/Kconfig

2e27beeb66e43f3b84aef5a07e486a5d50695c06 - timekeeping: Allow inlining clocksource::read()

Tue, 24 Feb 2026 17:36:20 +0100

timekeeping: Allow inlining clocksource::read()On some architectures clocksource::read() boils down to a singleinstruction, so the indirect function call is just a massive overheadespecially with speculative execution mitigations in effect.Allow architectures to enable conditional inlining of that read to avoidthat by: - providing a static branch to switch to the inlined variant - disabling the branch before clocksource changes - enabling the branch after a clocksource change, when the clocksource indicates in a feature flag that it is the one which provides the inlined variantThis is intentionally not a static call as that would only remove theindirect call, but not the rest of the overhead.Signed-off-by: Thomas Gleixner Signed-off-by: Peter Zijlstra (Intel) Link: https://patch.msgid.link/20260224163429.675151545@kernel.org List of files: /linux/kernel/time/Kconfig

cb9f145f638d7afa633632a9290d6ad06caeb8ee - Merge remote-tracking branch 'drm/drm-next' into msm-next-robclark

Sat, 01 Nov 2025 13:47:30 +0100

Merge remote-tracking branch 'drm/drm-next' into msm-next-robclarkBack-merge drm-next to get caught up.Signed-off-by: Rob Clark List of files: /linux/kernel/time/Kconfig

f088104d837a991c65e51fa30bb4196169b3244d - Merge drm/drm-next into drm-intel-gt-next

Tue, 16 Sep 2025 12:53:20 +0200

Merge drm/drm-next into drm-intel-gt-nextBackmerge in order to get the commit: 048832a3f400 ("drm/i915: Refactor shmem_pwrite() to use kiocb and write_iter")To drm-intel-gt-next as there are followup fixes to be applied.Signed-off-by: Joonas Lahtinen List of files: /linux/kernel/time/Kconfig

a53d0cf7f1cb3182ad533ff5cacfa5fd29c419ad - Merge commit 'linus' into core/bugs, to resolve conflicts

Tue, 05 Aug 2025 11:15:34 +0200

Merge commit 'linus' into core/bugs, to resolve conflictsResolve conflicts with this commit that was developed in parallelduring the merge window: 8c8efa93db68 ("x86/bug: Add ARCH_WARN_ASM macro for BUG/WARN asm code sharing with Rust") Conflicts: arch/riscv/include/asm/bug.h arch/x86/include/asm/bug.hSigned-off-by: Ingo Molnar List of files: /linux/kernel/time/Kconfig

8b87f67b4c87452e21721887fa8dec1f4c6b2b7c - Merge branch 'next' into for-linus

Wed, 08 Oct 2025 06:53:13 +0200

Merge branch 'next' into for-linusPrepare input updates for 6.18 merge window. List of files: /linux/kernel/time/Kconfig

4b051897df2375414587a245ecb9bb1a4d26b3b8 - Merge tag 'v6.17-rc2' into HEAD

Thu, 21 Aug 2025 20:46:49 +0200

Merge tag 'v6.17-rc2' into HEADSync up with mainline to bring in changes to include/linux/sprintf.h List of files: /linux/kernel/time/Kconfig

b4d90dbc4c1bc4bd3eb2d2989330af0eb95c98e8 - Merge drm/drm-next into drm-misc-next-fixes

Mon, 15 Sep 2025 10:23:28 +0200

Merge drm/drm-next into drm-misc-next-fixesBackmerging to drm-misc-next-fixes to get features and fixes fromv6.17-rc6.Signed-off-by: Thomas Zimmermann List of files: /linux/kernel/time/Kconfig

702fdf3513b045f596f836d9a4b8672c76f11834 - Merge drm/drm-next into drm-intel-next

Wed, 10 Sep 2025 14:01:42 +0200

Merge drm/drm-next into drm-intel-nextCatching up with some display dependencies.Signed-off-by: Rodrigo Vivi List of files: /linux/kernel/time/Kconfig

ca994e8922f25f7fed2075098f185cf198109eaa - Merge drm/drm-next into drm-xe-next

Tue, 12 Aug 2025 14:58:37 +0200

Merge drm/drm-next into drm-xe-nextBring v6.17-rc1 to propagate commits from other subsystems, particularlyPCI, which has some new functions needed for SR-IOV integration.Signed-off-by: Lucas De Marchi List of files: /linux/kernel/time/Kconfig

08c51f5bddc81c8c97c1eb11861b0dc009e5ccd8 - Merge drm/drm-next into drm-misc-n

Mon, 11 Aug 2025 14:37:45 +0200

Merge drm/drm-next into drm-misc-nUpdating drm-misc-next to the state of v6.17-rc1. Begins a new releasecycle.Signed-off-by: Thomas Zimmermann List of files: /linux/kernel/time/Kconfig