Hello Linus, When the merge window opens, please pull this RCU update from: git://git.kernel.org/pub/scm/linux/kernel/git/rcu/linux.git tags/rcu.release.v6.12 # HEAD: 355debb83bf79853cde43579f88eed16adb1da29: Merge branches 'context_tracking.15.08.24a', 'csd.lock.15.08.24a', 'nocb.09.09.24a', 'rcutorture.14.08.24a', 'rcustall.09.09.24a', 'srcu.12.08.24a', 'rcu.tasks.14.08.24a', 'rcu_scaling_tests.15.08.24a', 'fixes.12.08.24a' and 'misc.11.08.24a' into next.09.09.24a (2024-09-09 00:09:47 +0530) Following are the merge conflicts with other trees: 1. Merge conflicts with slab tree Stephen's resolution: https://lore.kernel.org/lkml/20240812124748.3725011b@xxxxxxxxxxxxxxxx/ In case you might want to refer to it, a sample tree with resolutions applied is at git://git.kernel.org/pub/scm/linux/kernel/git/rcu/linux.git heads/rcu.v6.12.slab.tree.conflict_res 2. Merge conflict with kvm-fixes tree Stephen's resolution: https://lore.kernel.org/lkml/20240905154122.4d1f8ca5@xxxxxxxxxxxxxxxx/ In case you might want to refer to it, a sample tree with resolutions applied is at git://git.kernel.org/pub/scm/linux/kernel/git/rcu/linux.git heads/rcu.v6.12.kvm-fixes.tree.conflict_res ---------------------------------------------------------------- RCU pull request for v6.12 This pull request contains the following branches: context_tracking.15.08.24a: Rename context tracking state related symbols and remove references to "dynticks" in various context tracking state variables and related helpers; force context_tracking_enabled_this_cpu() to be inlined to avoid leaving a noinstr section. csd.lock.15.08.24a: Enhance CSD-lock diagnostic reports; add an API to provide an indication of ongoing CSD-lock stall. nocb.09.09.24a: Update and simplify RCU nocb code to handle (de-)offloading of callbacks only for offline CPUs; fix RT throttling hrtimer being armed from offline CPU. rcutorture.14.08.24a: Remove redundant rcu_torture_ops get_gp_completed fields; add SRCU ->same_gp_state and ->get_comp_state functions; add generic test for NUM_ACTIVE_*RCU_POLL* for testing RCU and SRCU polled grace periods; add CFcommon.arch for arch-specific Kconfig options; print number of update types in rcu_torture_write_types(); add rcutree.nohz_full_patience_delay testing to the TREE07 scenario; add a stall_cpu_repeat module parameter to test repeated CPU stalls; add argument to limit number of CPUs a guest OS can use in torture.sh; rcustall.09.09.24a: Abbreviate RCU CPU stall warnings during CSD-lock stalls; Allow dump_cpu_task() to be called without disabling preemption; defer printing stall-warning backtrace when holding rcu_node lock. srcu.12.08.24a: Make SRCU gp seq wrap-around faster; add KCSAN checks for concurrent updates to ->srcu_n_exp_nodelay and ->reschedule_count which are used in heuristics governing auto-expediting of normal SRCU grace periods and grace-period-state-machine delays; mark idle SRCU-barrier callbacks to help identify stuck SRCU-barrier callback. rcu.tasks.14.08.24a: Remove RCU Tasks Rude asynchronous APIs as they are no longer used; stop testing RCU Tasks Rude asynchronous APIs; fix access to non-existent percpu regions; check processor-ID assumptions during chosen CPU calculation for callback enqueuing; update description of rtp->tasks_gp_seq grace-period sequence number; add rcu_barrier_cb_is_done() to identify whether a given rcu_barrier callback is stuck; mark idle Tasks-RCU-barrier callbacks; add *torture_stats_print() functions to print detailed diagnostics for Tasks-RCU variants; capture start time of rcu_barrier_tasks*() operation to help distinguish a hung barrier operation from a long series of barrier operations. rcu_scaling_tests.15.08.24a: refscale: Add a TINY scenario to support tests of Tiny RCU and Tiny SRCU; Optimize process_durations() operation; rcuscale: Dump stacks of stalled rcu_scale_writer() instances; dump grace-period statistics when rcu_scale_writer() stalls; mark idle RCU-barrier callbacks to identify stuck RCU-barrier callbacks; print detailed grace-period and barrier diagnostics on rcu_scale_writer() hangs for Tasks-RCU variants; warn if async module parameter is specified for RCU implementations that do not have async primitives such as RCU Tasks Rude; make all writer tasks report upon hang; tolerate repeated GFP_KERNEL failure in rcu_scale_writer(); use special allocator for rcu_scale_writer(); NULL out top-level pointers to heap memory to avoid double-free bugs on modprobe failures; maintain per-task instead of per-CPU callbacks count to avoid any issues with migration of either tasks or callbacks; constify struct ref_scale_ops. fixes.12.08.24a: Use system_unbound_wq for kfree_rcu work to avoid disturbing isolated CPUs. misc.11.08.24a: Warn on unexpected rcu_state.srs_done_tail state; Better define "atomic" for list_replace_rcu() and hlist_replace_rcu() routines; annotate struct kvfree_rcu_bulk_data with __counted_by(). ---------------------------------------------------------------- Christophe JAILLET (2): refscale: Optimize process_durations() refscale: Constify struct ref_scale_ops Frederic Weisbecker (14): rcu/nocb: Introduce RCU_NOCB_LOCKDEP_WARN() rcu/nocb: Move nocb field at the end of state struct rcu/nocb: Assert no callbacks while nocb kthread allocation fails rcu/nocb: Introduce nocb mutex rcu/nocb: (De-)offload callbacks on offline CPUs only rcu/nocb: Remove halfway (de-)offloading handling from bypass rcu/nocb: Remove halfway (de-)offloading handling from rcu_core()'s QS reporting rcu/nocb: Remove halfway (de-)offloading handling from rcu_core rcu/nocb: Remove SEGCBLIST_RCU_CORE rcu/nocb: Remove SEGCBLIST_KTHREAD_CB rcu/nocb: Simplify (de-)offloading state machine rcu/nocb: Fix RT throttling hrtimer armed from offline CPU rcu/nocb: Conditionally wake up rcuo if not already waiting on GP rcu/nocb: Remove superfluous memory barrier after bypass enqueue JP Kobryn (1): srcu: faster gp seq wrap-around Neeraj Upadhyay (1): Merge branches 'context_tracking.15.08.24a', 'csd.lock.15.08.24a', 'nocb.09.09.24a', 'rcutorture.14.08.24a', 'rcustall.09.09.24a', 'srcu.12.08.24a', 'rcu.tasks.14.08.24a', 'rcu_scaling_tests.15.08.24a', 'fixes.12.08.24a' and 'misc.11.08.24a' into next.09.09.24a Paul E. McKenney (41): rcutorture: Remove redundant rcu_torture_ops get_gp_completed fields rcutorture: Add SRCU ->same_gp_state and ->get_comp_state functions rcutorture: Generic test for NUM_ACTIVE_*RCU_POLL* rcutorture: Make rcu_torture_write_types() print number of update types tools/rcu: Remove RCU Tasks Rude asynchronous APIs from rcu-updaters.sh rcu/kfree: Warn on unexpected tail state locking/csd_lock: Print large numbers as negatives rcu: Better define "atomic" for list replacement rcutorture: Add rcutree.nohz_full_patience_delay to TREE07 srcu: Check for concurrent updates of heuristics srcu: Mark callbacks not currently participating in barrier operation rcutorture: Add a stall_cpu_repeat module parameter torture: Add torture.sh --guest-cpu-limit argument for limited hosts doc: Remove RCU Tasks Rude asynchronous APIs rcutorture: Stop testing RCU Tasks Rude asynchronous APIs rcuscale: Stop testing RCU Tasks Rude asynchronous APIs rcu-tasks: Remove RCU Tasks Rude asynchronous APIs rcu/tasks: Check processor-ID assumptions rcu/tasks: Update rtp->tasks_gp_seq comment rcu: Provide rcu_barrier_cb_is_done() to check rcu_barrier() CBs rcu/tasks: Mark callbacks not currently participating in barrier operation rcu/tasks: Add detailed grace-period and barrier diagnostics rcu/tasks: Add rcu_barrier_tasks*() start time to diagnostics refscale: Add TINY scenario rcuscale: Save a few lines with whitespace-only change rcuscale: Dump stacks of stalled rcu_scale_writer() instances rcuscale: Dump grace-period statistics when rcu_scale_writer() stalls rcu: Mark callbacks not currently participating in barrier operation rcuscale: Print detailed grace-period and barrier diagnostics locking/csd_lock: Provide an indication of ongoing CSD-lock stall locking/csd-lock: Use backoff for repeated reports of same incident rcu: Summarize RCU CPU stall warnings during CSD-lock stalls rcu: Extract synchronize_rcu_expedited_stall() from synchronize_rcu_expedited_wait() rcu: Summarize expedited RCU CPU stall warnings during CSD-lock stalls rcuscale: Provide clear error when async specified without primitives rcuscale: Make all writer tasks report upon hang rcuscale: Make rcu_scale_writer() tolerate repeated GFP_KERNEL failure rcuscale: Use special allocator for rcu_scale_writer() rcuscale: NULL out top-level pointers to heap memory rcuscale: Count outstanding callbacks per-task rather than per-CPU rcu: Defer printing stall-warning backtrace when holding rcu_node lock Rik van Riel (1): smp: print only local CPU info when sched_clock goes backward Ryo Takakura (1): rcu: Let dump_cpu_task() be used without preemption disabled Sean Christopherson (1): context_tracking: Tag context_tracking_enabled_this_cpu() __always_inline Thorsten Blum (1): rcu: Annotate struct kvfree_rcu_bulk_data with __counted_by() Valentin Schneider (25): treewide: context_tracking: Rename CONTEXT_* into CT_STATE_* context_tracking, rcu: Rename RCU_DYNTICKS_IDX into CT_RCU_WATCHING context_tracking, rcu: Rename ct_dynticks() into ct_rcu_watching() context_tracking, rcu: Rename ct_dynticks_cpu() into ct_rcu_watching_cpu() context_tracking, rcu: Rename ct_dynticks_cpu_acquire() into ct_rcu_watching_cpu_acquire() context_tracking, rcu: Rename struct context_tracking .dynticks_nesting into .nesting context_tracking, rcu: Rename ct_dynticks_nesting() into ct_nesting() context_tracking, rcu: Rename ct_dynticks_nesting_cpu() into ct_nesting_cpu() context_tracking, rcu: Rename struct context_tracking .dynticks_nmi_nesting into .nmi_nesting context_tracking, rcu: Rename ct_dynticks_nmi_nesting() into ct_nmi_nesting() context_tracking, rcu: Rename ct_dynticks_nmi_nesting_cpu() into ct_nmi_nesting_cpu() context_tracking, rcu: Rename DYNTICK_IRQ_NONIDLE into CT_NESTING_IRQ_NONIDLE context_tracking, rcu: Rename rcu_dynticks_task*() into rcu_task*() context_tracking, rcu: Rename rcu_dynticks_curr_cpu_in_eqs() into rcu_is_watching_curr_cpu() rcu: Rename rcu_dynticks_eqs_online() into rcu_watching_online() rcu: Rename rcu_dynticks_in_eqs() into rcu_watching_snap_in_eqs() rcu: Rename rcu_dynticks_in_eqs_since() into rcu_watching_snap_stopped_since() rcu: Rename rcu_dynticks_zero_in_eqs() into rcu_watching_zero_in_eqs() rcu: Rename struct rcu_data .dynticks_snap into .watching_snap rcu: Rename struct rcu_data .exp_dynticks_snap into .exp_watching_snap rcu: Rename dyntick_save_progress_counter() into rcu_watching_snap_save() rcu: Rename rcu_implicit_dynticks_qs() into rcu_watching_snap_recheck() rcu: Rename rcu_momentary_dyntick_idle() into rcu_momentary_eqs() rcu: Update stray documentation references to rcu_dynticks_eqs_{enter, exit}() context_tracking, rcu: Rename rcu_dyntick trace event into rcu_watching Waiman Long (1): rcu: Use system_unbound_wq to avoid disturbing isolated CPUs Zhouyi Zhou (1): rcutorture: Add CFcommon.arch for arch-specific Kconfig options Zqiang (1): rcu-tasks: Fix access non-existent percpu rtpcp variable in rcu_tasks_need_gpcb() Documentation/RCU/Design/Data-Structures/Data-Structures.rst | 28 +++--- Documentation/RCU/Design/Memory-Ordering/Tree-RCU-Memory-Ordering.rst | 8 +- Documentation/RCU/Design/Memory-Ordering/TreeRCU-dyntick.svg | 8 +- Documentation/RCU/Design/Memory-Ordering/TreeRCU-gp-fqs.svg | 8 +- Documentation/RCU/Design/Memory-Ordering/TreeRCU-gp.svg | 8 +- Documentation/RCU/Design/Memory-Ordering/TreeRCU-hotplug.svg | 4 +- Documentation/RCU/Design/Requirements/Requirements.rst | 3 +- Documentation/RCU/checklist.rst | 61 ++++++------ Documentation/RCU/whatisRCU.rst | 2 +- Documentation/admin-guide/kernel-parameters.txt | 20 ++-- arch/Kconfig | 2 +- arch/arm64/kernel/entry-common.c | 2 +- arch/powerpc/include/asm/interrupt.h | 6 +- arch/powerpc/kernel/interrupt.c | 6 +- arch/powerpc/kernel/syscall.c | 2 +- arch/x86/entry/common.c | 2 +- include/linux/context_tracking.h | 32 ++++--- include/linux/context_tracking_state.h | 60 ++++++------ include/linux/entry-common.h | 2 +- include/linux/rcu_segcblist.h | 6 +- include/linux/rculist.h | 9 +- include/linux/rcupdate.h | 15 ++- include/linux/rcutiny.h | 2 +- include/linux/rcutree.h | 2 +- include/linux/smp.h | 6 ++ include/linux/srcutree.h | 15 ++- include/trace/events/rcu.h | 20 ++-- kernel/context_tracking.c | 140 ++++++++++++++-------------- kernel/entry/common.c | 2 +- kernel/rcu/rcu.h | 12 ++- kernel/rcu/rcu_segcblist.c | 11 --- kernel/rcu/rcu_segcblist.h | 11 +-- kernel/rcu/rcuscale.c | 214 ++++++++++++++++++++++++++++++++++++------ kernel/rcu/rcutorture.c | 121 +++++++++++++++--------- kernel/rcu/refscale.c | 67 ++++++------- kernel/rcu/srcutree.c | 11 ++- kernel/rcu/tasks.h | 214 ++++++++++++++++++++++++++++-------------- kernel/rcu/tree.c | 174 ++++++++++++++++------------------ kernel/rcu/tree.h | 10 +- kernel/rcu/tree_exp.h | 121 +++++++++++++----------- kernel/rcu/tree_nocb.h | 279 +++++++++++++++++++++---------------------------------- kernel/rcu/tree_plugin.h | 11 ++- kernel/rcu/tree_stall.h | 16 +++- kernel/sched/core.c | 6 +- kernel/smp.c | 38 +++++++- kernel/stop_machine.c | 2 +- kernel/trace/trace_osnoise.c | 4 +- lib/Kconfig.debug | 1 + tools/rcu/rcu-updaters.sh | 2 - tools/testing/selftests/rcutorture/bin/kvm-test-1-run.sh | 2 + tools/testing/selftests/rcutorture/bin/torture.sh | 38 +++++--- tools/testing/selftests/rcutorture/configs/rcu/CFcommon | 2 - tools/testing/selftests/rcutorture/configs/rcu/CFcommon.i686 | 2 + tools/testing/selftests/rcutorture/configs/rcu/CFcommon.ppc64le | 1 + tools/testing/selftests/rcutorture/configs/rcu/CFcommon.x86_64 | 2 + tools/testing/selftests/rcutorture/configs/rcu/TREE07.boot | 1 + tools/testing/selftests/rcutorture/configs/refscale/TINY | 20 ++++ 57 files changed, 1088 insertions(+), 786 deletions(-) create mode 100644 tools/testing/selftests/rcutorture/configs/rcu/CFcommon.i686 create mode 100644 tools/testing/selftests/rcutorture/configs/rcu/CFcommon.ppc64le create mode 100644 tools/testing/selftests/rcutorture/configs/rcu/CFcommon.x86_64 create mode 100644 tools/testing/selftests/rcutorture/configs/refscale/TINY
