Messages in this thread | | | From | Frederic Weisbecker <> | Subject | [PATCH 00/19] rcu/context-tracking: Merge RCU eqs-dynticks counter to context tracking | Date | Wed, 2 Mar 2022 16:47:51 +0100 |
| |
This mixes up the RCU dynticks counter and the context tracking state updates into a single atomic instruction. This may serve several purposes:
1) Improve CPU isolation with deferring some disturbances until sensitive userspace workload completes and goes to the kernel. This can take several forms, for example smp_call_function_housekeeping() or on_each_housekeeping_cpu() to enqueue and execute work on all housekeeping CPUs. Then an atomic operation on ct->state can defer the work on nohz_full CPUs until they run in kernel (or IPI them if they are in kernel mode), see this proposal by Peter: https://lore.kernel.org/all/20210929151723.162004989@infradead.org/#r
2) Unearth sysidle (https://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git/commit/?h=sysidle.2017.05.11a&id=fe5ac724d81a3c7803e60c2232718f212f3f38d4) This feature allowed to shutdown the tick on the last housekeeping CPU once the rest of the system is fully idle. We needed some proper fully ordered context tracking for that.
Inspired by Peterz: https://lore.kernel.org/all/20210929151723.162004989@infradead.org
git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks.git rcu/context-tracking
HEAD: e4eaff86ec91c1cbde9a113cf5232dac9f897337
Thanks, Frederic ---
Frederic Weisbecker (19): context_tracking: Rename __context_tracking_enter/exit() to __ct_user_enter/exit() context_tracking: Rename context_tracking_user_enter/exit() to user_enter/exit_callable() context_tracking: Rename context_tracking_enter/exit() to ct_user_enter/exit() context_tracking: Rename context_tracking_cpu_set() to context_tracking_cpu_track_user() context_tracking: Split user tracking Kconfig context_tracking: Take idle eqs entrypoints over RCU context_tracking: Take IRQ eqs entrypoints over RCU context_tracking: Take NMI eqs entrypoints over RCU rcu/context-tracking: Remove rcu_irq_enter/exit() rcu/context_tracking: Move dynticks counter to context tracking rcu/context_tracking: Move dynticks_nesting to context tracking rcu/context_tracking: Move dynticks_nmi_nesting to context tracking rcu/context-tracking: Move deferred nocb resched to context tracking rcu/context-tracking: Move RCU-dynticks internal functions to context_tracking rcu/context-tracking: Remove unused and/or unecessary middle functions context_tracking: Convert state to atomic_t rcu/context-tracking: Use accessor for dynticks counter value rcu/context_tracking: Merge dynticks counter and context tracking states context_tracking: Exempt CONFIG_HAVE_CONTEXT_TRACKING_USER_OFFSTACK from non-active tracking
.../RCU/Design/Requirements/Requirements.rst | 10 +- Documentation/RCU/stallwarn.rst | 6 +- .../time/context-tracking/arch-support.txt | 6 +- arch/Kconfig | 8 +- arch/arm/Kconfig | 2 +- arch/arm/kernel/entry-common.S | 4 +- arch/arm/kernel/entry-header.S | 12 +- arch/arm/mach-imx/cpuidle-imx6q.c | 5 +- arch/arm64/Kconfig | 2 +- arch/arm64/kernel/entry-common.c | 14 +- arch/csky/Kconfig | 2 +- arch/csky/kernel/entry.S | 8 +- arch/mips/Kconfig | 2 +- arch/powerpc/Kconfig | 2 +- arch/powerpc/include/asm/context_tracking.h | 2 +- arch/riscv/Kconfig | 2 +- arch/riscv/kernel/entry.S | 12 +- arch/sparc/Kconfig | 2 +- arch/sparc/kernel/rtrap_64.S | 2 +- arch/x86/Kconfig | 4 +- arch/x86/mm/fault.c | 2 +- drivers/acpi/processor_idle.c | 5 +- drivers/cpuidle/cpuidle-psci.c | 8 +- drivers/cpuidle/cpuidle.c | 9 +- include/linux/context_tracking.h | 81 ++-- include/linux/context_tracking_irq.h | 21 + include/linux/context_tracking_state.h | 92 +++- include/linux/entry-common.h | 10 +- include/linux/hardirq.h | 12 +- include/linux/rcupdate.h | 7 +- include/linux/rcutiny.h | 6 - include/linux/rcutree.h | 15 +- include/linux/tracepoint.h | 4 +- init/Kconfig | 4 +- kernel/context_tracking.c | 526 +++++++++++++++++++-- kernel/cpu_pm.c | 8 +- kernel/entry/common.c | 16 +- kernel/extable.c | 4 +- kernel/locking/lockdep.c | 2 +- kernel/rcu/Kconfig | 2 + kernel/rcu/rcu.h | 4 - kernel/rcu/tree.c | 478 ++----------------- kernel/rcu/tree.h | 8 - kernel/rcu/tree_exp.h | 2 +- kernel/rcu/tree_plugin.h | 36 +- kernel/rcu/tree_stall.h | 7 +- kernel/rcu/update.c | 2 +- kernel/sched/core.c | 2 +- kernel/sched/idle.c | 11 +- kernel/softirq.c | 4 +- kernel/time/Kconfig | 22 +- kernel/time/tick-sched.c | 2 +- kernel/trace/trace.c | 8 +- 53 files changed, 793 insertions(+), 734 deletions(-)
| |