mirror-linux/kernel
Peter Zijlstra 15dd3a9488 hrtimer: Push reprogramming timers into the interrupt return path
Currently hrtimer_interrupt() runs expired timers, which can re-arm
themselves, after which it computes the next expiration time and
re-programs the hardware.

However, things like HRTICK, a highres timer driving preemption, cannot
re-arm itself at the point of running, since the next task has not been
determined yet. The schedule() in the interrupt return path will switch to
the next task, which then causes a new hrtimer to be programmed.

This then results in reprogramming the hardware at least twice, once after
running 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 return
path, it runs after schedule() picks the new task and the double reprogram
can be avoided.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260224163431.273488269@kernel.org
2026-02-27 16:40:14 +01:00
..
bpf Convert remaining multi-line kmalloc_obj/flex GFP_KERNEL uses 2026-02-22 08:26:33 -08:00
cgroup Convert 'alloc_flex' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
configs watchdog: softlockup: panic when lockup duration exceeds N thresholds 2026-01-20 19:44:20 -08:00
debug treewide: Replace kmalloc with kmalloc_obj for non-scalar types 2026-02-21 01:02:28 -08:00
dma Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
entry entry: Prepare for deferred hrtimer rearming 2026-02-27 16:40:13 +01:00
events Convert remaining multi-line kmalloc_obj/flex GFP_KERNEL uses 2026-02-22 08:26:33 -08:00
futex Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
gcov Convert more 'alloc_obj' cases to default GFP_KERNEL arguments 2026-02-21 20:03:00 -08:00
irq Convert 'alloc_flex' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
kcsan Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
livepatch Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
liveupdate Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
locking Convert remaining multi-line kmalloc_obj/flex GFP_KERNEL uses 2026-02-22 08:26:33 -08:00
module Convert 'alloc_flex' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
power Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
printk Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
rcu Convert remaining multi-line kmalloc_obj/flex GFP_KERNEL uses 2026-02-22 08:26:33 -08:00
sched sched/core: Prepare for deferred hrtimer rearming 2026-02-27 16:40:13 +01:00
time hrtimer: Push reprogramming timers into the interrupt return path 2026-02-27 16:40:14 +01:00
trace Convert remaining multi-line kmalloc_obj/flex GFP_KERNEL uses 2026-02-22 08:26:33 -08:00
unwind Convert more 'alloc_obj' cases to default GFP_KERNEL arguments 2026-02-21 20:03:00 -08:00
.gitignore
Kconfig.freezer
Kconfig.hz
Kconfig.kexec liveupdate: kho: move to kernel/liveupdate 2025-11-27 14:24:33 -08:00
Kconfig.locks
Kconfig.preempt sched: Further restrict the preemption modes 2026-01-08 12:43:57 +01:00
Makefile kcov: Enable context analysis 2026-01-05 16:43:34 +01:00
acct.c Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
async.c Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
audit.c Convert 'alloc_flex' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
audit.h audit: fix comment misindentation in audit.h 2025-10-22 19:28:06 -04:00
audit_fsnotify.c Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
audit_tree.c Convert 'alloc_flex' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
audit_watch.c Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
auditfilter.c Convert 'alloc_flex' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
auditsc.c Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
backtracetest.c
bounds.c x86/asm: Remove ANNOTATE_DATA_SPECIAL usage 2025-12-03 16:53:19 +01:00
capability.c
cfi.c
compat.c
configs.c
context_tracking.c context_tracking: Remove rcu_task_trace_heavyweight_{enter,exit}() 2026-01-01 16:39:46 +08:00
cpu.c SPDX updates for 7.0-rc1 2026-02-17 09:46:03 -08:00
cpu_pm.c syscore: Pass context data to callbacks 2025-11-14 10:01:52 +01:00
crash_core.c Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
crash_core_test.c crash: add KUnit tests for crash_exclude_mem_range 2025-09-13 17:32:55 -07:00
crash_dump_dm_crypt.c Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
crash_reserve.c crash: let architecture decide crash memory export to iomem_resource 2025-11-12 10:00:15 -08:00
cred.c cred: remove unused set_security_override_from_ctx() 2026-01-06 20:52:57 -05:00
delayacct.c delayacct: fix uapi timespec64 definition 2026-02-08 00:13:32 -08:00
dma.c
elfcorehdr.c
exec_domain.c
exit.c Significant patch series in this pull request: 2025-12-06 14:01:20 -08:00
exit.h
extable.c
fail_function.c Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
fork.c mm.git review status for linus..mm-nonmm-stable 2026-02-12 12:13:01 -08:00
freezer.c freezer: Clarify that only cgroup1 freezer uses PM freezer 2025-10-30 20:10:27 +01:00
gen_kheaders.sh
groups.c treewide: Replace kmalloc with kmalloc_obj for non-scalar types 2026-02-21 01:02:28 -08:00
hung_task.c hung_task: add hung_task_sys_info sysctl to dump sys info on task-hung 2025-11-20 14:03:43 -08:00
iomem.c
irq_work.c
jump_label.c
kallsyms.c mm.git review status for linus..mm-nonmm-stable 2026-02-12 12:13:01 -08:00
kallsyms_internal.h kallsyms: Get rid of kallsyms relative base 2026-01-22 15:58:22 -07:00
kallsyms_selftest.c Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
kallsyms_selftest.h
kcmp.c
kcov.c Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
kexec.c Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
kexec_core.c Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
kexec_elf.c
kexec_file.c kexec: derive purgatory entry from symbol 2026-01-31 16:16:07 -08:00
kexec_internal.h
kheaders.c
kprobes.c Convert 'alloc_flex' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
kstack_erase.c sysctl: remove __user qualifier from stack_erasing_sysctl buffer argument 2025-11-27 15:44:53 +01:00
ksyms_common.c
ksysfs.c kexec: move sysfs entries to /sys/kernel/kexec 2025-11-27 14:24:42 -08:00
kthread.c Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
latencytop.c
module_signature.c
notifier.c
nscommon.c ns: rename is_initial_namespace() 2025-11-11 10:01:31 +01:00
nsproxy.c nsproxy: fix free_nsproxy() and simplify create_new_namespaces() 2025-11-14 13:10:38 +01:00
nstree.c nstree: fix kernel-doc comments for internal functions 2025-11-14 13:10:38 +01:00
padata.c Convert more 'alloc_obj' cases to default GFP_KERNEL arguments 2026-02-21 20:03:00 -08:00
panic.c panic: add panic_force_cpu= parameter to redirect panic to a specific CPU 2026-02-03 08:21:26 -08:00
params.c Convert more 'alloc_obj' cases to default GFP_KERNEL arguments 2026-02-21 20:03:00 -08:00
pid.c Revert "pid: make __task_pid_nr_ns(ns => NULL) safe for zombie callers" 2026-02-10 11:39:30 +01:00
pid_namespace.c pid: rely on common reference count behavior 2025-11-11 10:01:32 +01:00
pid_sysctl.h
profile.c
ptrace.c rseq: Introduce struct rseq_data 2025-11-04 08:30:50 +01:00
range.c
reboot.c treewide: Replace kmalloc with kmalloc_obj for non-scalar types 2026-02-21 01:02:28 -08:00
regset.c
relay.c Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
resource.c Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
resource_kunit.c Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
rseq.c rseq: Lower default slice extension 2026-01-22 11:11:20 +01:00
scftorture.c Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
scs.c scs: fix a wrong parameter in __scs_magic 2025-11-12 10:00:13 -08:00
seccomp.c Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
signal.c compiler-context-analysis: Remove __cond_lock() function-like helper 2026-01-05 16:43:33 +01:00
smp.c smp: Introduce a helper function to check for pending IPIs 2025-11-19 18:06:50 +01:00
smpboot.c
smpboot.h
softirq.c softirq: Prepare for deferred hrtimer rearming 2026-02-27 16:40:13 +01:00
stacktrace.c
static_call.c
static_call_inline.c Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
stop_machine.c
sys.c RISC-V updates for v7.0 2026-02-12 19:17:44 -08:00
sys_ni.c rseq: Implement sys_rseq_slice_yield() 2026-01-22 11:11:17 +01:00
sysctl-test.c
sysctl.c sysctl: replace SYSCTL_INT_CONV_CUSTOM macro with functions 2026-01-06 11:27:10 +01:00
task_work.c task_work: Fix NMI race condition 2025-10-29 10:29:54 +01:00
taskstats.c
torture.c Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
tracepoint.c Convert 'alloc_flex' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
tsacct.c tsacct: skip all kernel threads 2026-01-26 19:07:13 -08:00
ucount.c Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
uid16.c
uid16.h
umh.c treewide: Replace kmalloc with kmalloc_obj for non-scalar types 2026-02-21 01:02:28 -08:00
up.c
user-return-notifier.c
user.c ns: drop custom reference count initialization for initial namespaces 2025-11-11 10:01:32 +01:00
user_namespace.c Convert remaining multi-line kmalloc_obj/flex GFP_KERNEL uses 2026-02-22 08:26:33 -08:00
utsname.c namespace-6.18-rc1 2025-09-29 11:20:29 -07:00
utsname_sysctl.c
vhost_task.c Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
vmcore_info.c mm.git review status for linus..mm-nonmm-stable 2026-02-12 12:13:01 -08:00
watch_queue.c Convert 'alloc_flex' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
watchdog.c watchdog/softlockup: fix sample ring index wrap in need_counting_irqs() 2026-02-08 00:13:34 -08:00
watchdog_buddy.c
watchdog_perf.c watchdog/hardlockup: simplify perf event probe and remove per-cpu dependency 2026-02-08 00:13:35 -08:00
workqueue.c Convert 'alloc_flex' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
workqueue_internal.h