linux.git/kernel/rcu/tree_stall.h, branch v5.6 Linux kernel source tree Merge branches 'doc.2019.12.10a', 'exp.2019.12.09a', 'fixes.2020.01.24a', 'kfree_rcu.2020.01.24a', 'list.2020.01.10a', 'preempt.2020.01.24a' and 'torture.2019.12.09a' into HEAD 2020-01-24T18:37:27+00:00 Paul E. McKenney paulmck@kernel.org 2020-01-24T18:37:27+00:00 0e247386d9ed5ab8b7dad010cf4b183efeb1e47d doc.2019.12.10a: Documentations updates exp.2019.12.09a: Expedited grace-period updates fixes.2020.01.24a: Miscellaneous fixes kfree_rcu.2020.01.24a: Batch kfree_rcu() work list.2020.01.10a: RCU-protected-list updates preempt.2020.01.24a: Preemptible RCU updates torture.2019.12.09a: Torture-test updates 
doc.2019.12.10a: Documentations updates
exp.2019.12.09a: Expedited grace-period updates
fixes.2020.01.24a: Miscellaneous fixes
kfree_rcu.2020.01.24a: Batch kfree_rcu() work
list.2020.01.10a: RCU-protected-list updates
preempt.2020.01.24a: Preemptible RCU updates
torture.2019.12.09a: Torture-test updates
rcu: Move gp_state_names[] and gp_state_getname() to tree_stall.h 2020-01-24T18:33:45+00:00 Lai Jiangshan jiangshanlai@gmail.com 2019-10-15T10:28:47+00:00 e2167b38c87a0c9e85c342a823dae1e6f67b11d9 Only tree_stall.h needs to get name from GP state, so this commit moves the gp_state_names[] array and the gp_state_getname() from kernel/rcu/tree.h and kernel/rcu/tree.c, respectively, to kernel/rcu/tree_stall.h. While moving gp_state_names[], this commit uses the GCC syntax to ensure that the right string is associated with the right CPP macro. Signed-off-by: Lai Jiangshan <jiangshanlai@gmail.com> Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> 
Only tree_stall.h needs to get name from GP state, so this commit
moves the gp_state_names[] array and the gp_state_getname()
from kernel/rcu/tree.h and kernel/rcu/tree.c, respectively, to
kernel/rcu/tree_stall.h.  While moving gp_state_names[], this commit
uses the GCC syntax to ensure that the right string is associated with
the right CPP macro.

Signed-off-by: Lai Jiangshan <jiangshanlai@gmail.com>
Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
rcu: Rename some instance of CONFIG_PREEMPTION to CONFIG_PREEMPT_RCU 2020-01-24T18:26:28+00:00 Lai Jiangshan jiangshanlai@gmail.com 2019-10-15T10:28:48+00:00 c130d2dc93cd03323494d82dbe7b5fb0d101ab62 CONFIG_PREEMPTION and CONFIG_PREEMPT_RCU are always identical, but some code depends on CONFIG_PREEMPTION to access to rcu_preempt functionality. This patch changes CONFIG_PREEMPTION to CONFIG_PREEMPT_RCU in these cases. Signed-off-by: Lai Jiangshan <jiangshanlai@gmail.com> Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> 
CONFIG_PREEMPTION and CONFIG_PREEMPT_RCU are always identical,
but some code depends on CONFIG_PREEMPTION to access to
rcu_preempt functionality. This patch changes CONFIG_PREEMPTION
to CONFIG_PREEMPT_RCU in these cases.

Signed-off-by: Lai Jiangshan <jiangshanlai@gmail.com>
Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
rcu: Remove kfree_rcu() special casing and lazy-callback handling 2020-01-24T18:24:31+00:00 Joel Fernandes (Google) joel@joelfernandes.org 2019-08-30T16:36:32+00:00 77a40f97030b27b3fc1640a3ed203870f0817f57 This commit removes kfree_rcu() special-casing and the lazy-callback handling from Tree RCU. It moves some of this special casing to Tiny RCU, the removal of which will be the subject of later commits. This results in a nice negative delta. Suggested-by: Paul E. McKenney <paulmck@linux.ibm.com> Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org> [ paulmck: Add slab.h #include, thanks to kbuild test robot <lkp@intel.com>. ] Signed-off-by: Paul E. McKenney <paulmck@kernel.org> 
This commit removes kfree_rcu() special-casing and the lazy-callback
handling from Tree RCU.  It moves some of this special casing to Tiny RCU,
the removal of which will be the subject of later commits.

This results in a nice negative delta.

Suggested-by: Paul E. McKenney <paulmck@linux.ibm.com>
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
[ paulmck: Add slab.h #include, thanks to kbuild test robot <lkp@intel.com>. ]
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-09-17T00:25:49+00:00 Linus Torvalds torvalds@linux-foundation.org 2019-09-17T00:25:49+00:00 7e67a859997aad47727aff9c5a32e160da079ce3 Pull scheduler updates from Ingo Molnar: - MAINTAINERS: Add Mark Rutland as perf submaintainer, Juri Lelli and Vincent Guittot as scheduler submaintainers. Add Dietmar Eggemann, Steven Rostedt, Ben Segall and Mel Gorman as scheduler reviewers. As perf and the scheduler is getting bigger and more complex, document the status quo of current responsibilities and interests, and spread the review pain^H^H^H^H fun via an increase in the Cc: linecount generated by scripts/get_maintainer.pl. :-) - Add another series of patches that brings the -rt (PREEMPT_RT) tree closer to mainline: split the monolithic CONFIG_PREEMPT dependencies into a new CONFIG_PREEMPTION category that will allow the eventual introduction of CONFIG_PREEMPT_RT. Still a few more hundred patches to go though. - Extend the CPU cgroup controller with uclamp.min and uclamp.max to allow the finer shaping of CPU bandwidth usage. - Micro-optimize energy-aware wake-ups from O(CPUS^2) to O(CPUS). - Improve the behavior of high CPU count, high thread count applications running under cpu.cfs_quota_us constraints. - Improve balancing with SCHED_IDLE (SCHED_BATCH) tasks present. - Improve CPU isolation housekeeping CPU allocation NUMA locality. - Fix deadline scheduler bandwidth calculations and logic when cpusets rebuilds the topology, or when it gets deadline-throttled while it's being offlined. - Convert the cpuset_mutex to percpu_rwsem, to allow it to be used from setscheduler() system calls without creating global serialization. Add new synchronization between cpuset topology-changing events and the deadline acceptance tests in setscheduler(), which were broken before. - Rework the active_mm state machine to be less confusing and more optimal. - Rework (simplify) the pick_next_task() slowpath. - Improve load-balancing on AMD EPYC systems. - ... and misc cleanups, smaller fixes and improvements - please see the Git log for more details. * 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (53 commits) sched/psi: Correct overly pessimistic size calculation sched/fair: Speed-up energy-aware wake-ups sched/uclamp: Always use 'enum uclamp_id' for clamp_id values sched/uclamp: Update CPU's refcount on TG's clamp changes sched/uclamp: Use TG's clamps to restrict TASK's clamps sched/uclamp: Propagate system defaults to the root group sched/uclamp: Propagate parent clamps sched/uclamp: Extend CPU's cgroup controller sched/topology: Improve load balancing on AMD EPYC systems arch, ia64: Make NUMA select SMP sched, perf: MAINTAINERS update, add submaintainers and reviewers sched/fair: Use rq_lock/unlock in online_fair_sched_group cpufreq: schedutil: fix equation in comment sched: Rework pick_next_task() slow-path sched: Allow put_prev_task() to drop rq->lock sched/fair: Expose newidle_balance() sched: Add task_struct pointer to sched_class::set_curr_task sched: Rework CPU hotplug task selection sched/{rt,deadline}: Fix set_next_task vs pick_next_task sched: Fix kerneldoc comment for ia64_set_curr_task ... 
Pull scheduler updates from Ingo Molnar:

 - MAINTAINERS: Add Mark Rutland as perf submaintainer, Juri Lelli and
   Vincent Guittot as scheduler submaintainers. Add Dietmar Eggemann,
   Steven Rostedt, Ben Segall and Mel Gorman as scheduler reviewers.

   As perf and the scheduler is getting bigger and more complex,
   document the status quo of current responsibilities and interests,
   and spread the review pain^H^H^H^H fun via an increase in the Cc:
   linecount generated by scripts/get_maintainer.pl. :-)

 - Add another series of patches that brings the -rt (PREEMPT_RT) tree
   closer to mainline: split the monolithic CONFIG_PREEMPT dependencies
   into a new CONFIG_PREEMPTION category that will allow the eventual
   introduction of CONFIG_PREEMPT_RT. Still a few more hundred patches
   to go though.

 - Extend the CPU cgroup controller with uclamp.min and uclamp.max to
   allow the finer shaping of CPU bandwidth usage.

 - Micro-optimize energy-aware wake-ups from O(CPUS^2) to O(CPUS).

 - Improve the behavior of high CPU count, high thread count
   applications running under cpu.cfs_quota_us constraints.

 - Improve balancing with SCHED_IDLE (SCHED_BATCH) tasks present.

 - Improve CPU isolation housekeeping CPU allocation NUMA locality.

 - Fix deadline scheduler bandwidth calculations and logic when cpusets
   rebuilds the topology, or when it gets deadline-throttled while it's
   being offlined.

 - Convert the cpuset_mutex to percpu_rwsem, to allow it to be used from
   setscheduler() system calls without creating global serialization.
   Add new synchronization between cpuset topology-changing events and
   the deadline acceptance tests in setscheduler(), which were broken
   before.

 - Rework the active_mm state machine to be less confusing and more
   optimal.

 - Rework (simplify) the pick_next_task() slowpath.

 - Improve load-balancing on AMD EPYC systems.

 - ... and misc cleanups, smaller fixes and improvements - please see
   the Git log for more details.

* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (53 commits)
  sched/psi: Correct overly pessimistic size calculation
  sched/fair: Speed-up energy-aware wake-ups
  sched/uclamp: Always use 'enum uclamp_id' for clamp_id values
  sched/uclamp: Update CPU's refcount on TG's clamp changes
  sched/uclamp: Use TG's clamps to restrict TASK's clamps
  sched/uclamp: Propagate system defaults to the root group
  sched/uclamp: Propagate parent clamps
  sched/uclamp: Extend CPU's cgroup controller
  sched/topology: Improve load balancing on AMD EPYC systems
  arch, ia64: Make NUMA select SMP
  sched, perf: MAINTAINERS update, add submaintainers and reviewers
  sched/fair: Use rq_lock/unlock in online_fair_sched_group
  cpufreq: schedutil: fix equation in comment
  sched: Rework pick_next_task() slow-path
  sched: Allow put_prev_task() to drop rq->lock
  sched/fair: Expose newidle_balance()
  sched: Add task_struct pointer to sched_class::set_curr_task
  sched: Rework CPU hotplug task selection
  sched/{rt,deadline}: Fix set_next_task vs pick_next_task
  sched: Fix kerneldoc comment for ia64_set_curr_task
  ...
rcu/nocb: Print no-CBs diagnostics when rcutorture writer unduly delayed 2019-08-13T21:38:24+00:00 Paul E. McKenney paulmck@linux.ibm.com 2019-06-25T20:32:51+00:00 f7a81b12d6af42a9d09be1e5f041169f04b0b67a This commit causes locking, sleeping, and callback state to be printed for no-CBs CPUs when the rcutorture writer is delayed sufficiently for rcutorture to complain. Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com> 
This commit causes locking, sleeping, and callback state to be printed
for no-CBs CPUs when the rcutorture writer is delayed sufficiently for
rcutorture to complain.

Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
rcu: Add kernel parameter to dump trace after RCU CPU stall warning 2019-08-01T21:05:51+00:00 Paul E. McKenney paulmck@linux.ibm.com 2019-06-13T22:30:49+00:00 cdc694b2359d52cd6d0465d5a6263d97c786fb0c This commit adds a rcu_cpu_stall_ftrace_dump kernel boot parameter, that, when set, causes the trace buffer to be dumped after an RCU CPU stall warning is printed. This kernel boot parameter is disabled by default, maintaining compatibility with previous behavior. Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com> 
This commit adds a rcu_cpu_stall_ftrace_dump kernel boot parameter, that,
when set, causes the trace buffer to be dumped after an RCU CPU stall
warning is printed.  This kernel boot parameter is disabled by default,
maintaining compatibility with previous behavior.

Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
rcu: Use CONFIG_PREEMPTION 2019-07-31T17:03:35+00:00 Thomas Gleixner tglx@linutronix.de 2019-07-26T21:19:38+00:00 01b1d88b09824bea1a75b0bac04dcf50d9893875 CONFIG_PREEMPTION is selected by CONFIG_PREEMPT and by CONFIG_PREEMPT_RT. Both PREEMPT and PREEMPT_RT require the same functionality which today depends on CONFIG_PREEMPT. Switch the conditionals in RCU to use CONFIG_PREEMPTION. That's the first step towards RCU on RT. The further tweaks are work in progress. This neither touches the selftest bits which need a closer look by Paul. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Paul E. McKenney <paulmck@linux.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Link: http://lkml.kernel.org/r/20190726212124.210156346@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org> 
CONFIG_PREEMPTION is selected by CONFIG_PREEMPT and by
CONFIG_PREEMPT_RT. Both PREEMPT and PREEMPT_RT require the same
functionality which today depends on CONFIG_PREEMPT.

Switch the conditionals in RCU to use CONFIG_PREEMPTION.

That's the first step towards RCU on RT. The further tweaks are work in
progress. This neither touches the selftest bits which need a closer look
by Paul.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Paul E. McKenney <paulmck@linux.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/20190726212124.210156346@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
rcu: Correctly unlock root node in rcu_check_gp_start_stall() 2019-05-28T16:02:57+00:00 Neeraj Upadhyay neeraju@codeaurora.org 2019-03-29T11:27:08+00:00 3ae976a7e3e87438b8439a01aeb79d4866b1c444 On systems whose rcu_node tree has only one node, the rcu_check_gp_start_stall() function's values of rnp and rnp_root will be identical. In this case, it clearly does not make sense to release both rnp->lock and rnp_root->lock, but that is exactly what this function does in the last early exit. This commit therefore unlocks only rnp->lock when rnp and rnp_root are equal. Signed-off-by: Neeraj Upadhyay <neeraju@codeaurora.org> Reviewed-by: Mukesh Ojha <mojha@codeaurora.org> Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com> 
On systems whose rcu_node tree has only one node, the
rcu_check_gp_start_stall() function's values of rnp and rnp_root will
be identical.  In this case, it clearly does not make sense to release
both rnp->lock and rnp_root->lock, but that is exactly what this function
does in the last early exit.  This commit therefore unlocks only rnp->lock
when rnp and rnp_root are equal.

Signed-off-by: Neeraj Upadhyay <neeraju@codeaurora.org>
Reviewed-by: Mukesh Ojha <mojha@codeaurora.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
rcu: Fix nohz status in stall warning 2019-03-26T21:42:00+00:00 Neeraj Upadhyay neeraju@codeaurora.org 2019-03-08T19:57:48+00:00 6c70e9cd5f3c6d93f3e1da6d101073e898f39170 The Documentation/RCU/stallwarn.txt file says that stall warnings print "D" if dyntick-idle processing is enabled, but the code in print_cpu_stall_fast_no_hz() prints "." instead. This commit therefore reverses the sense of the test to make the code match the documentation. Signed-off-by: Neeraj Upadhyay <neeraju@codeaurora.org> Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com> 
The Documentation/RCU/stallwarn.txt file says that stall warnings
print "D" if dyntick-idle processing is enabled, but the code in
print_cpu_stall_fast_no_hz() prints "." instead.  This commit therefore
reverses the sense of the test to make the code match the documentation.

Signed-off-by: Neeraj Upadhyay <neeraju@codeaurora.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>