Messages in this thread | | | Date | Tue, 2 Oct 2018 03:03:56 -0700 | From | "Paul E. McKenney" <> | Subject | Re: [GIT PULL rcu/next] RCU commits for 4.20/5.0 |
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On Tue, Oct 02, 2018 at 10:24:29AM +0200, Ingo Molnar wrote: > > * Paul E. McKenney <paulmck@linux.ibm.com> wrote: > > > Hello, Ingo, > > > > This pull request contains the following changes: > > > > 1. Documentation updates, including some good-eye catches from > > Joel Fernandes. > > > > http://lkml.kernel.org/r/20180829211637.GA20980@linux.vnet.ibm.com > > > > 2. SRCU updates, most notably changes enabling call_srcu() to be > > invoked very early in the boot sequence. > > > > http://lkml.kernel.org/r/20180829212036.GA22033@linux.vnet.ibm.com > > > > 3. Torture-test updates, including some preliminary work towards > > making rcutorture better able to find problems that result in > > insufficient grace-period forward progress. > > > > http://lkml.kernel.org/r/20180829214722.GA23411@linux.vnet.ibm.com > > > > 4. Consolidate the RCU-bh, RCU-preempt, and RCU-sched flavors into > > a single flavor similar to RCU-sched in !PREEMPT kernels and > > into a single flavor similar to RCU-preempt (but also waiting > > on preempt-disabled sequences of code) in PREEMPT kernels. This > > branch also includes a refactoring of rcu_{nmi,irq}_{enter,exit}() > > from Byungchul Park. > > > > http://lkml.kernel.org/r/20180829222021.GA29944@linux.vnet.ibm.com > > > > 5. Now that there is only one RCU flavor in any given running kernel, > > the many "rsp" pointers are no longer required, and this cleanup > > series removes them. > > > > http://lkml.kernel.org/r/20180829223830.GA1800@linux.vnet.ibm.com > > > > 6. This branch carries out additional cleanups made possible by > > the RCU flavor consolidation, including inlining how-trivial > > functions, updating comments and definitions, and removing > > now-unneeded rcutorture scenarios. > > > > http://lkml.kernel.org/r/20180829225340.GA7019@linux.vnet.ibm.com > > > > 7. Initial changes to RCU to better promote forward progress of > > grace periods, including fixing a bug found by Marius Hillenbrand > > and David Woodhouse, with the fix suggested by Peter Zijlstra. > > > > http://lkml.kernel.org/r/20180829230035.GA7751@linux.vnet.ibm.com > > > > 8. Now that there is only one flavor of RCU in any running kernel, > > there is also only on rcu_data structure per CPU. This means > > that the rcu_dynticks structure can be merged into the rcu_data > > structure, a task taken on by this branch. This branch also > > contains a -rt-related fix from Mike Galbraith. > > > > http://lkml.kernel.org/r/20180829230715.GA9431@linux.vnet.ibm.com > > > > Once again, the layout of this pull request is unusual due to the large > > footprint of the commits in #4-#8 above. These five branches are therefore > > stacked on top of each other instead of my usual practice of laying them > > out in parallel. > > > > This pull request decreases the size of RCU by more than 450 lines, > > offsetting the increase of the v4.19 merge window. I expect a further > > decrease due to additional outside-of-RCU cleanups, though this will be > > offset by additional forward-progress testing and fixes in response to > > Marius's and David's location of a forward-progress bug that escaped to > > the field -- rcutorture should have located that bug, after all. > > > > All of these changes have been subjected to 0day Test Robot and -next > > testing, and are available in the git repository at: > > > > git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git for-mingo > > > > for you to fetch changes up to b56ada120921fbb0a4fb2a5bee163717182e7e9e: > > > > Merge branches 'doc.2018.08.30a', 'dynticks.2018.08.30b', 'srcu.2018.08.30b' and 'torture.2018.08.29a' into HEAD (2018-08-30 16:12:53 -0700) > > > > ---------------------------------------------------------------- > > Byungchul Park (1): > > rcu: Refactor rcu_{nmi,irq}_{enter,exit}() > > > > Joel Fernandes (Google) (2): > > doc: Fix broken RCU-requirements link to LKML archive > > doc: Improve rcu_dynticks::dynticks documentation > > > > Mike Galbraith (1): > > rcu: Convert rcu_state.ofl_lock to raw_spinlock_t > > > > Paul E. McKenney (137): > > doc: Add design documentation on interruption of NMI handlers > > torture: Stop overwriting Make.out file with obsolete version > > rcutorture: Force occasional reader waits > > rcutorture: Warn on bad torture type for built-in tests > > rcuperf: Warn on bad perf type for built-in tests > > rcutorture: Remove TREE06 and TREE08 from the default test list > > rcutorture: Add forward-progress tests for RCU grace periods > > rcutorture: Also use GP sequence to judge forward progress > > rcutorture: Avoid no-test complaint if too few forward-progress tries > > rcutorture: Vary forward-progress test interval > > rcutorture: Add self-propagating callback to forward-progress testing > > rcutorture: Increase rcu_read_delay() longdelay_ms > > rcutorture: Limit reader duration if irq or bh disabled > > rcutorture: Reduce priority of forward-progress testing > > rcutorture: Adjust number of reader kthreads per CPU-hotplug operations > > rcutorture: Print forward-progress test interval on error > > rcutorture: Check GP completion at stutter end > > rcutorture: Maintain self-propagating CB only during forward-progress test > > doc: Update removal of RCU-bh/sched update machinery > > doc: Fix broken HTML directive > > rcu: Defer reporting RCU-preempt quiescent states when disabled > > rcutorture: Test extended "rcu" read-side critical sections > > rcu: Allow processing deferred QSes for exiting RCU-preempt readers > > rcu: Remove now-unused ->b.exp_need_qs field from the rcu_special union > > rcu: Add warning to detect half-interrupts > > rcu: Apply RCU-bh QSes to RCU-sched and RCU-preempt when safe > > rcu: Report expedited grace periods at context-switch time > > rcu: Define RCU-bh update API in terms of RCU > > rcu: Update comments and help text for no more RCU-bh updaters > > rcu: Drop "wake" parameter from rcu_report_exp_rdp() > > rcu: Fix typo in rcu_get_gp_kthreads_prio() header comment > > rcu: Define RCU-sched API in terms of RCU for Tree RCU PREEMPT builds > > rcu: Express Tiny RCU updates in terms of RCU rather than RCU-sched > > rcu: Remove RCU_STATE_INITIALIZER() > > rcu: Eliminate rcu_state structure's ->call field > > rcu: Remove rcu_state structure's ->rda field > > rcu: Remove rcu_state_p pointer to default rcu_state structure > > rcu: Remove rcu_data_p pointer to default rcu_data structure > > rcu: Remove rsp parameter from rcu_report_qs_rnp() > > rcu: Remove rsp parameter from rcu_report_qs_rsp() > > rcu: Remove rsp parameter from rcu_report_unblock_qs_rnp() > > rcu: Remove rsp parameter from rcu_report_qs_rdp() > > rcu: Remove rsp parameter from rcu_gp_in_progress() > > rcu: Remove rsp parameter from rcu_get_root() > > rcu: Remove rsp parameter from record_gp_stall_check_time() > > rcu: Remove rsp parameter from rcu_check_gp_kthread_starvation() > > rcu: Remove rsp parameter from rcu_dump_cpu_stacks() > > rcu: Remove rsp parameter from rcu_stall_kick_kthreads() > > rcu: Remove rsp parameter from print_other_cpu_stall() > > rcu: Remove rsp parameter from print_cpu_stall() > > rcu: Remove rsp parameter from check_cpu_stall() > > rcu: Remove rsp parameter from rcu_future_gp_cleanup() > > rcu: Remove rsp parameter from rcu_gp_kthread_wake() > > rcu: Remove rsp parameter from rcu_accelerate_cbs() > > rcu: Remove rsp parameter from rcu_accelerate_cbs_unlocked() > > rcu: Remove rsp parameter from rcu_advance_cbs() > > rcu: Remove rsp parameter from __note_gp_changes() > > rcu: Remove rsp parameter from note_gp_changes() > > rcu: Remove rsp parameter from rcu_gp_slow() > > rcu: Remove rsp parameter from rcu_gp_kthread() and friends > > rcu: Remove rsp parameter from rcu_check_quiescent_state() > > rcu: Remove rsp parameter from CPU hotplug functions > > rcu: Remove rsp parameter from rcu_do_batch() > > rcu: Remove rsp parameter from force-quiescent-state functions > > rcu: Remove rsp parameter from rcu_check_gp_start_stall() > > rcu: Remove rsp parameter from __rcu_process_callbacks() > > rcu: Remove rsp parameter from __call_rcu() and friend > > rcu: Remove rsp parameter from __rcu_pending() > > rcu: Remove rsp parameter from _rcu_barrier() and friends > > rcu: Remove rsp parameter from rcu_boot_init_percpu_data() and friends > > rcu: Remove rsp parameter from rcu_init_one() and friends > > rcu: Remove rsp parameter from rcu_print_detail_task_stall() > > rcu: Remove rsp parameter from dump_blkd_tasks() and friend > > rcu: Remove rsp parameter from rcu_spawn_one_boost_kthread() > > rcu: Remove rsp parameter from print_cpu_stall_info() > > rcu: Remove rsp parameter from no-CBs CPU functions > > rcu: Remove rsp parameter from expedited grace-period functions > > rcu: Remove rsp parameter from rcu_node tree accessor macros > > rcu: Remove rcu_data structure's ->rsp field > > rcu: Remove last non-flavor-traversal rsp local variable from tree_plugin.h > > rcu: Remove for_each_rcu_flavor() flavor-traversal macro > > rcu: Simplify rcutorture_get_gp_data() > > rcu: Restructure rcu_check_gp_kthread_starvation() > > rcu: Eliminate stall-warning use of rsp > > rcu: Eliminate grace-period management code use of rsp > > rcu: Eliminate callback-invocation/invocation use of rsp > > rcu: Eliminate quiescent-state and grace-period-nonstart use of rsp > > rcu: Eliminate RCU-barrier use of rsp > > rcu: Eliminate initialization-time use of rsp > > rcu: Fix typo in force_qs_rnp()'s parameter's parameter > > rcu: Inline increment_cpu_stall_ticks() into its sole caller > > rcu: Pull rcu_gp_kthread() FQS loop into separate function > > rcu: Consolidate RCU-bh update-side function definitions > > rcu: Consolidate RCU-sched update-side function definitions > > rcutorture: Add RCU-bh and RCU-sched support for extended readers > > rcu: Stop testing RCU-bh and RCU-sched > > rcutorture: Remove the "rcu_bh" and "sched" torture types > > rcuperf: Remove the "rcu_bh" and "sched" torture types > > rcu: Remove now-unused rcutorture APIs > > rcu: Clean up flavor-related definitions and comments in rcupdate.h > > rcu: Clean up flavor-related definitions and comments in rculist.h > > rcu: Clean up flavor-related definitions and comments in rcupdate_wait.h > > rcu: Clean up flavor-related definitions and comments in Kconfig > > rcu: Clean up flavor-related definitions and comments in rcu.h > > rcu: Clean up flavor-related definitions and comments in rcutorture.c > > rcu: Clean up flavor-related definitions and comments in srcutree.h > > rcu: Clean up flavor-related definitions and comments in tiny.c > > rcu: Clean up flavor-related definitions and comments in tree.c > > rcu: Clean up flavor-related definitions and comments in tree_exp.h > > rcu: Clean up flavor-related definitions and comments in tree_plugin.h > > rcu: Clean up flavor-related definitions and comments in update.c > > rcu: Remove !PREEMPT code from rcu_note_voluntary_context_switch() > > rcu: Define rcu_all_qs() only in !PREEMPT builds > > rcu: Inline _rcu_barrier() into its sole remaining caller > > rcu: Make need_resched() respond to urgent RCU-QS needs > > rcu: Provide improved interrupt-from-idle check in rcu_check_callbacks() > > rcutorture: Dump reader protection sequence if failures or close calls > > rcu: Motivate Tiny RCU forward progress > > rcu: Eliminate ->rcu_qs_ctr from the rcu_dynticks structure > > rcu: Provide functions for determining if call_rcu() has been invoked > > rcu: Compute jiffies_till_sched_qs from other kernel parameters > > rcu: More aggressively enlist scheduler aid for nohz_full CPUs > > rcu: Avoid resched_cpu() when rescheduling the current CPU > > rcu: Convert "1UL << x" to "BIT(x)" > > rcu: Remove unused rcu_dynticks_snap() from Tiny RCU > > rcu: Merge rcu_dynticks structure into rcu_data structure > > rcu: Switch ->tick_nohz_enabled_snap to rcu_data structure > > rcu: Switch last accelerate/advance to rcu_data structure > > rcu: Switch lazy counts to rcu_data structure > > rcu: Switch urgent quiescent-state requests to rcu_data structure > > rcu: Switch dyntick nesting counters to rcu_data structure > > rcu: Switch ->dynticks to rcu_data structure, remove rcu_dynticks > > rcu: Remove obsolete ->dynticks_fqs and ->cond_resched_completed > > srcu: Make call_srcu() available during very early boot > > rcutorture: Test early boot call_srcu() > > srcu: Make early-boot call_srcu() reuse workqueue lists > > Merge branches 'doc.2018.08.30a', 'dynticks.2018.08.30b', 'srcu.2018.08.30b' and 'torture.2018.08.29a' into HEAD > > > > .../Design/Data-Structures/Data-Structures.html | 31 +- > > .../Expedited-Grace-Periods.html | 9 +- > > .../RCU/Design/Requirements/Requirements.html | 214 +- > > Documentation/RCU/stallwarn.txt | 13 +- > > Documentation/RCU/whatisRCU.txt | 3 +- > > Documentation/admin-guide/kernel-parameters.txt | 31 +- > > Documentation/kernel-per-CPU-kthreads.txt | 2 +- > > include/linux/rculist.h | 32 +- > > include/linux/rcupdate.h | 154 +- > > include/linux/rcupdate_wait.h | 14 +- > > include/linux/rcutiny.h | 53 +- > > include/linux/rcutree.h | 31 +- > > include/linux/sched.h | 6 +- > > include/linux/srcutree.h | 13 +- > > include/linux/torture.h | 2 +- > > include/trace/events/rcu.h | 25 +- > > kernel/rcu/Kconfig | 14 +- > > kernel/rcu/rcu.h | 67 +- > > kernel/rcu/rcuperf.c | 66 +- > > kernel/rcu/rcutorture.c | 397 ++-- > > kernel/rcu/srcutiny.c | 29 +- > > kernel/rcu/srcutree.c | 31 +- > > kernel/rcu/tiny.c | 154 +- > > kernel/rcu/tree.c | 2213 ++++++++------------ > > kernel/rcu/tree.h | 132 +- > > kernel/rcu/tree_exp.h | 426 ++-- > > kernel/rcu/tree_plugin.h | 790 +++---- > > kernel/rcu/update.c | 70 +- > > kernel/softirq.c | 3 +- > > kernel/torture.c | 3 +- > > .../selftests/rcutorture/bin/kvm-test-1-run.sh | 1 - > > .../selftests/rcutorture/configs/rcu/CFLIST | 2 - > > .../selftests/rcutorture/configs/rcu/SRCU-P.boot | 1 + > > .../selftests/rcutorture/configs/rcu/SRCU-u.boot | 1 + > > .../selftests/rcutorture/configs/rcu/TINY02.boot | 2 - > > .../selftests/rcutorture/configs/rcu/TREE01.boot | 2 +- > > .../selftests/rcutorture/configs/rcu/TREE04.boot | 2 +- > > .../selftests/rcutorture/configs/rcu/TREE05.boot | 3 +- > > .../selftests/rcutorture/configs/rcu/TREE06.boot | 2 - > > .../selftests/rcutorture/configs/rcu/TREE08.boot | 2 - > > 40 files changed, 2294 insertions(+), 2752 deletions(-) > > Pulled into tip:core/rcu, thanks a lot Paul! > > The code and complexity reduction from the consolidation of the RCU models is pretty > impressive IMO! :-)
Glad you like it! ;-)
Which reminds me...
If you are running rcutorture in -tip on NO_HZ_FULL kernel with RCU callback offloading enabled, you are not extremely excited about getting splats from rcutorture's new forward-progress testing, I reccommend that you add "rcutorture.fwd_progress=0" to your kernel boot parameters. I added forward-progress testing because of people finding a forward-progress issue in real-life testing. (The fix to that specific issue is included and called out in #7 above.)
Thanx, Paul
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