Before commit 076cbf5d2163 ("x86/xen: don't let xen_pv_play_dead()
return"), in Xen, when a previously offlined CPU was brought back
online, it unexpectedly resumed execution where it left off in the
middle of the idle loop.
There were some hacks to make that work, but the behavior was surprising
as do_idle() doesn't expect an offlined CPU to return from the dead (in
arch_cpu_idle_dead()).
Now that Xen has been fixed, and the arch-specific implementations of
arch_cpu_idle_dead() also don't return, give it a __noreturn attribute.
This will cause the compiler to complain if an arch-specific
implementation might return. It also improves code generation for both
caller and callee.
Also fixes the following warning:
vmlinux.o: warning: objtool: do_idle+0x25f: unreachable instruction
Reported-by: Paul E. McKenney <paulmck@kernel.org>
Tested-by: Paul E. McKenney <paulmck@kernel.org>
Link: https://lore.kernel.org/r/60d527353da8c99d4cf13b6473131d46719ed16d.1676358308.git.jpoimboe@kernel.org
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
arch_cpu_idle_dead() should never return. Make it so. Link: https://lore.kernel.org/r/cf5ad95eef50f7704bb30e7770c59bfe23372af7.1676358308.git.jpoimboe@kernel.org Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Current arch_cpu_idle() is called with IRQs disabled, but will return with IRQs enabled. However, the very first thing the generic code does after calling arch_cpu_idle() is raw_local_irq_disable(). This means that architectures that can idle with IRQs disabled end up doing a pointless 'enable-disable' dance. Therefore, push this IRQ disabling into the idle function, meaning that those architectures can avoid the pointless IRQ state flipping. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Tested-by: Tony Lindgren <tony@atomide.com> Tested-by: Ulf Hansson <ulf.hansson@linaro.org> Reviewed-by: Gautham R. Shenoy <gautham.shenoy@amd.com> Acked-by: Mark Rutland <mark.rutland@arm.com> [arm64] Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Guo Ren <guoren@kernel.org> Acked-by: Frederic Weisbecker <frederic@kernel.org> Link: https://lore.kernel.org/r/20230112195540.618076436@infradead.org
The whole disable-RCU, enable-IRQS dance is very intricate since changing IRQ state is traced, which depends on RCU. Add two helpers for the cpuidle case that mirror the entry code: ct_cpuidle_enter() ct_cpuidle_exit() And fix all the cases where the enter/exit dance was buggy. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Tested-by: Tony Lindgren <tony@atomide.com> Tested-by: Ulf Hansson <ulf.hansson@linaro.org> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Frederic Weisbecker <frederic@kernel.org> Link: https://lore.kernel.org/r/20230112195540.130014793@infradead.org
The RCU dynticks counter is going to be merged into the context tracking subsystem. Start with moving the idle extended quiescent states entrypoints to context tracking. For now those are dumb redirections to existing RCU calls. [ paulmck: Apply kernel test robot feedback. ] Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Neeraj Upadhyay <quic_neeraju@quicinc.com> Cc: Uladzislau Rezki <uladzislau.rezki@sony.com> Cc: Joel Fernandes <joel@joelfernandes.org> Cc: Boqun Feng <boqun.feng@gmail.com> Cc: Nicolas Saenz Julienne <nsaenz@kernel.org> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Xiongfeng Wang <wangxiongfeng2@huawei.com> Cc: Yu Liao <liaoyu15@huawei.com> Cc: Phil Auld <pauld@redhat.com> Cc: Paul Gortmaker<paul.gortmaker@windriver.com> Cc: Alex Belits <abelits@marvell.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Reviewed-by: Nicolas Saenz Julienne <nsaenzju@redhat.com> Tested-by: Nicolas Saenz Julienne <nsaenzju@redhat.com>
Pull scheduler updates from Ingo Molnar:
- Updates to scheduler metrics:
- PELT fixes & enhancements
- PSI fixes & enhancements
- Refactor cpu_util_without()
- Updates to instrumentation/debugging:
- Remove sched_trace_*() helper functions - can be done via debug
info
- Fix double update_rq_clock() warnings
- Introduce & use "preemption model accessors" to simplify some of the
Kconfig complexity.
- Make softirq handling RT-safe.
- Misc smaller fixes & cleanups.
* tag 'sched-core-2022-05-23' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
topology: Remove unused cpu_cluster_mask()
sched: Reverse sched_class layout
sched/deadline: Remove superfluous rq clock update in push_dl_task()
sched/core: Avoid obvious double update_rq_clock warning
smp: Make softirq handling RT safe in flush_smp_call_function_queue()
smp: Rename flush_smp_call_function_from_idle()
sched: Fix missing prototype warnings
sched/fair: Remove cfs_rq_tg_path()
sched/fair: Remove sched_trace_*() helper functions
sched/fair: Refactor cpu_util_without()
sched/fair: Revise comment about lb decision matrix
sched/psi: report zeroes for CPU full at the system level
sched/fair: Delete useless condition in tg_unthrottle_up()
sched/fair: Fix cfs_rq_clock_pelt() for throttled cfs_rq
sched/fair: Move calculate of avg_load to a better location
mailmap: Update my email address to @redhat.com
MAINTAINERS: Add myself as scheduler topology reviewer
psi: Fix trigger being fired unexpectedly at initial
ftrace: Use preemption model accessors for trace header printout
kcsan: Use preemption model accessors
Pull locking updates from Ingo Molnar:
- rwsem cleanups & optimizations/fixes:
- Conditionally wake waiters in reader/writer slowpaths
- Always try to wake waiters in out_nolock path
- Add try_cmpxchg64() implementation, with arch optimizations - and use
it to micro-optimize sched_clock_{local,remote}()
- Various force-inlining fixes to address objdump instrumentation-check
warnings
- Add lock contention tracepoints:
lock:contention_begin
lock:contention_end
- Misc smaller fixes & cleanups
* tag 'locking-core-2022-05-23' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
sched/clock: Use try_cmpxchg64 in sched_clock_{local,remote}
locking/atomic/x86: Introduce arch_try_cmpxchg64
locking/atomic: Add generic try_cmpxchg64 support
futex: Remove a PREEMPT_RT_FULL reference.
locking/qrwlock: Change "queue rwlock" to "queued rwlock"
lockdep: Delete local_irq_enable_in_hardirq()
locking/mutex: Make contention tracepoints more consistent wrt adaptive spinning
locking: Apply contention tracepoints in the slow path
locking: Add lock contention tracepoints
locking/rwsem: Always try to wake waiters in out_nolock path
locking/rwsem: Conditionally wake waiters in reader/writer slowpaths
locking/rwsem: No need to check for handoff bit if wait queue empty
lockdep: Fix -Wunused-parameter for _THIS_IP_
x86/mm: Force-inline __phys_addr_nodebug()
x86/kvm/svm: Force-inline GHCB accessors
task_stack, x86/cea: Force-inline stack helpers
- sched/core is on a pretty old -rc1 base - refresh it to include recent fixes. - this also allows up to resolve a (trivial) .mailmap conflict Conflicts: .mailmap Signed-off-by: Ingo Molnar <mingo@kernel.org>
This is invoked from the stopper thread too, which is definitely not idle. Rename it to flush_smp_call_function_queue() and fixup the callers. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20220413133024.305001096@linutronix.de
While looking into a bug related to the compiler's handling of addresses of labels, I noticed some uses of _THIS_IP_ seemed unused in lockdep. Drive by cleanup. -Wunused-parameter: kernel/locking/lockdep.c:1383:22: warning: unused parameter 'ip' kernel/locking/lockdep.c:4246:48: warning: unused parameter 'ip' kernel/locking/lockdep.c:4844:19: warning: unused parameter 'ip' Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Waiman Long <longman@redhat.com> Link: https://lore.kernel.org/r/20220314221909.2027027-1-ndesaulniers@google.com