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[46.139.12.213]) by smtp.gmail.com with ESMTPSA id k93-v6sm1481235wrc.89.2018.10.02.01.24.31 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Tue, 02 Oct 2018 01:24:31 -0700 (PDT) Date: Tue, 2 Oct 2018 10:24:29 +0200 From: Ingo Molnar To: "Paul E. McKenney" Cc: linux-kernel@vger.kernel.org, josh@joshtriplett.org, rostedt@goodmis.org, mathieu.desnoyers@efficios.com, jiangshanlai@gmail.com, efault@gmx.de, byungchul.park@lge.com, joel@joelfernandes.org, mhillenb@amazon.de, dwmw2@infradead.org, peterz@infradead.org Subject: Re: [GIT PULL rcu/next] RCU commits for 4.20/5.0 Message-ID: <20181002082429.GA69893@gmail.com> References: <20180926182159.GA26116@linux.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180926182159.GA26116@linux.ibm.com> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Paul E. McKenney 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! :-) Ingo