rcu: Remove debugfs tracing
RCU's debugfs tracing used to be the only reasonable low-level debug information available, but ftrace and event tracing has since surpassed the RCU debugfs level of usefulness. This commit therefore removes RCU's debugfs tracing. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This commit is contained in:
parent
bd8cc5a062
commit
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@ -28,8 +28,6 @@ stallwarn.txt
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- RCU CPU stall warnings (module parameter rcu_cpu_stall_suppress)
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torture.txt
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- RCU Torture Test Operation (CONFIG_RCU_TORTURE_TEST)
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trace.txt
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- CONFIG_RCU_TRACE debugfs files and formats
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UP.txt
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- RCU on Uniprocessor Systems
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whatisRCU.txt
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@ -2034,7 +2034,7 @@ guard against mishaps and misuse:
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some other synchronization mechanism, for example, reference
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counting.
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<li> In kernels built with <tt>CONFIG_RCU_TRACE=y</tt>, RCU-related
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information is provided via both debugfs and event tracing.
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information is provided via event tracing.
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<li> Open-coded use of <tt>rcu_assign_pointer()</tt> and
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<tt>rcu_dereference()</tt> to create typical linked
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data structures can be surprisingly error-prone.
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@ -1,535 +0,0 @@
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CONFIG_RCU_TRACE debugfs Files and Formats
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The rcutree and rcutiny implementations of RCU provide debugfs trace
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output that summarizes counters and state. This information is useful for
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debugging RCU itself, and can sometimes also help to debug abuses of RCU.
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The following sections describe the debugfs files and formats, first
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for rcutree and next for rcutiny.
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CONFIG_TREE_RCU and CONFIG_PREEMPT_RCU debugfs Files and Formats
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These implementations of RCU provide several debugfs directories under the
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top-level directory "rcu":
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rcu/rcu_bh
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rcu/rcu_preempt
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rcu/rcu_sched
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Each directory contains files for the corresponding flavor of RCU.
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Note that rcu/rcu_preempt is only present for CONFIG_PREEMPT_RCU.
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For CONFIG_TREE_RCU, the RCU flavor maps onto the RCU-sched flavor,
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so that activity for both appears in rcu/rcu_sched.
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In addition, the following file appears in the top-level directory:
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rcu/rcutorture. This file displays rcutorture test progress. The output
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of "cat rcu/rcutorture" looks as follows:
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rcutorture test sequence: 0 (test in progress)
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rcutorture update version number: 615
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The first line shows the number of rcutorture tests that have completed
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since boot. If a test is currently running, the "(test in progress)"
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string will appear as shown above. The second line shows the number of
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update cycles that the current test has started, or zero if there is
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no test in progress.
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Within each flavor directory (rcu/rcu_bh, rcu/rcu_sched, and possibly
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also rcu/rcu_preempt) the following files will be present:
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rcudata:
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Displays fields in struct rcu_data.
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rcuexp:
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Displays statistics for expedited grace periods.
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rcugp:
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Displays grace-period counters.
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rcuhier:
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Displays the struct rcu_node hierarchy.
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rcu_pending:
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Displays counts of the reasons rcu_pending() decided that RCU had
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work to do.
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rcuboost:
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Displays RCU boosting statistics. Only present if
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CONFIG_RCU_BOOST=y.
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The output of "cat rcu/rcu_preempt/rcudata" looks as follows:
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0!c=30455 g=30456 cnq=1/0:1 dt=126535/140000000000000/0 df=2002 of=4 ql=0/0 qs=N... b=10 ci=74572 nci=0 co=1131 ca=716
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1!c=30719 g=30720 cnq=1/0:0 dt=132007/140000000000000/0 df=1874 of=10 ql=0/0 qs=N... b=10 ci=123209 nci=0 co=685 ca=982
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2!c=30150 g=30151 cnq=1/1:1 dt=138537/140000000000000/0 df=1707 of=8 ql=0/0 qs=N... b=10 ci=80132 nci=0 co=1328 ca=1458
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3 c=31249 g=31250 cnq=1/1:0 dt=107255/140000000000000/0 df=1749 of=6 ql=0/450 qs=NRW. b=10 ci=151700 nci=0 co=509 ca=622
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4!c=29502 g=29503 cnq=1/0:1 dt=83647/140000000000000/0 df=965 of=5 ql=0/0 qs=N... b=10 ci=65643 nci=0 co=1373 ca=1521
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5 c=31201 g=31202 cnq=1/0:1 dt=70422/0/0 df=535 of=7 ql=0/0 qs=.... b=10 ci=58500 nci=0 co=764 ca=698
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6!c=30253 g=30254 cnq=1/0:1 dt=95363/140000000000000/0 df=780 of=5 ql=0/0 qs=N... b=10 ci=100607 nci=0 co=1414 ca=1353
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7 c=31178 g=31178 cnq=1/0:0 dt=91536/0/0 df=547 of=4 ql=0/0 qs=.... b=10 ci=109819 nci=0 co=1115 ca=969
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This file has one line per CPU, or eight for this 8-CPU system.
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The fields are as follows:
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o The number at the beginning of each line is the CPU number.
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CPUs numbers followed by an exclamation mark are offline,
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but have been online at least once since boot. There will be
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no output for CPUs that have never been online, which can be
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a good thing in the surprisingly common case where NR_CPUS is
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substantially larger than the number of actual CPUs.
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o "c" is the count of grace periods that this CPU believes have
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completed. Offlined CPUs and CPUs in dynticks idle mode may lag
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quite a ways behind, for example, CPU 4 under "rcu_sched" above,
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which has been offline through 16 RCU grace periods. It is not
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unusual to see offline CPUs lagging by thousands of grace periods.
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Note that although the grace-period number is an unsigned long,
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it is printed out as a signed long to allow more human-friendly
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representation near boot time.
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o "g" is the count of grace periods that this CPU believes have
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started. Again, offlined CPUs and CPUs in dynticks idle mode
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may lag behind. If the "c" and "g" values are equal, this CPU
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has already reported a quiescent state for the last RCU grace
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period that it is aware of, otherwise, the CPU believes that it
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owes RCU a quiescent state.
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o "pq" indicates that this CPU has passed through a quiescent state
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for the current grace period. It is possible for "pq" to be
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"1" and "c" different than "g", which indicates that although
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the CPU has passed through a quiescent state, either (1) this
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CPU has not yet reported that fact, (2) some other CPU has not
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yet reported for this grace period, or (3) both.
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o "qp" indicates that RCU still expects a quiescent state from
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this CPU. Offlined CPUs and CPUs in dyntick idle mode might
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well have qp=1, which is OK: RCU is still ignoring them.
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o "dt" is the current value of the dyntick counter that is incremented
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when entering or leaving idle, either due to a context switch or
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due to an interrupt. This number is even if the CPU is in idle
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from RCU's viewpoint and odd otherwise. The number after the
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first "/" is the interrupt nesting depth when in idle state,
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or a large number added to the interrupt-nesting depth when
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running a non-idle task. Some architectures do not accurately
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count interrupt nesting when running in non-idle kernel context,
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which can result in interesting anomalies such as negative
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interrupt-nesting levels. The number after the second "/"
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is the NMI nesting depth.
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o "df" is the number of times that some other CPU has forced a
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quiescent state on behalf of this CPU due to this CPU being in
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idle state.
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o "of" is the number of times that some other CPU has forced a
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quiescent state on behalf of this CPU due to this CPU being
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offline. In a perfect world, this might never happen, but it
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turns out that offlining and onlining a CPU can take several grace
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periods, and so there is likely to be an extended period of time
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when RCU believes that the CPU is online when it really is not.
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Please note that erring in the other direction (RCU believing a
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CPU is offline when it is really alive and kicking) is a fatal
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error, so it makes sense to err conservatively.
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o "ql" is the number of RCU callbacks currently residing on
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this CPU. The first number is the number of "lazy" callbacks
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that are known to RCU to only be freeing memory, and the number
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after the "/" is the total number of callbacks, lazy or not.
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These counters count callbacks regardless of what phase of
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grace-period processing that they are in (new, waiting for
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grace period to start, waiting for grace period to end, ready
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to invoke).
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o "qs" gives an indication of the state of the callback queue
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with four characters:
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"N" Indicates that there are callbacks queued that are not
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ready to be handled by the next grace period, and thus
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will be handled by the grace period following the next
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one.
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"R" Indicates that there are callbacks queued that are
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ready to be handled by the next grace period.
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"W" Indicates that there are callbacks queued that are
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waiting on the current grace period.
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"D" Indicates that there are callbacks queued that have
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already been handled by a prior grace period, and are
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thus waiting to be invoked. Note that callbacks in
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the process of being invoked are not counted here.
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Callbacks in the process of being invoked are those
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that have been removed from the rcu_data structures
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queues by rcu_do_batch(), but which have not yet been
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invoked.
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If there are no callbacks in a given one of the above states,
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the corresponding character is replaced by ".".
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o "b" is the batch limit for this CPU. If more than this number
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of RCU callbacks is ready to invoke, then the remainder will
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be deferred.
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o "ci" is the number of RCU callbacks that have been invoked for
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this CPU. Note that ci+nci+ql is the number of callbacks that have
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been registered in absence of CPU-hotplug activity.
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o "nci" is the number of RCU callbacks that have been offloaded from
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this CPU. This will always be zero unless the kernel was built
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with CONFIG_RCU_NOCB_CPU=y and the "rcu_nocbs=" kernel boot
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parameter was specified.
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o "co" is the number of RCU callbacks that have been orphaned due to
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this CPU going offline. These orphaned callbacks have been moved
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to an arbitrarily chosen online CPU.
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o "ca" is the number of RCU callbacks that have been adopted by this
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CPU due to other CPUs going offline. Note that ci+co-ca+ql is
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the number of RCU callbacks registered on this CPU.
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Kernels compiled with CONFIG_RCU_BOOST=y display the following from
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/debug/rcu/rcu_preempt/rcudata:
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0!c=12865 g=12866 cnq=1/0:1 dt=83113/140000000000000/0 df=288 of=11 ql=0/0 qs=N... kt=0/O ktl=944 b=10 ci=60709 nci=0 co=748 ca=871
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1 c=14407 g=14408 cnq=1/0:0 dt=100679/140000000000000/0 df=378 of=7 ql=0/119 qs=NRW. kt=0/W ktl=9b6 b=10 ci=109740 nci=0 co=589 ca=485
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2 c=14407 g=14408 cnq=1/0:0 dt=105486/0/0 df=90 of=9 ql=0/89 qs=NRW. kt=0/W ktl=c0c b=10 ci=83113 nci=0 co=533 ca=490
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3 c=14407 g=14408 cnq=1/0:0 dt=107138/0/0 df=142 of=8 ql=0/188 qs=NRW. kt=0/W ktl=b96 b=10 ci=121114 nci=0 co=426 ca=290
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4 c=14405 g=14406 cnq=1/0:1 dt=50238/0/0 df=706 of=7 ql=0/0 qs=.... kt=0/W ktl=812 b=10 ci=34929 nci=0 co=643 ca=114
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5!c=14168 g=14169 cnq=1/0:0 dt=45465/140000000000000/0 df=161 of=11 ql=0/0 qs=N... kt=0/O ktl=b4d b=10 ci=47712 nci=0 co=677 ca=722
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6 c=14404 g=14405 cnq=1/0:0 dt=59454/0/0 df=94 of=6 ql=0/0 qs=.... kt=0/W ktl=e57 b=10 ci=55597 nci=0 co=701 ca=811
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7 c=14407 g=14408 cnq=1/0:1 dt=68850/0/0 df=31 of=8 ql=0/0 qs=.... kt=0/W ktl=14bd b=10 ci=77475 nci=0 co=508 ca=1042
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This is similar to the output discussed above, but contains the following
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additional fields:
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o "kt" is the per-CPU kernel-thread state. The digit preceding
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the first slash is zero if there is no work pending and 1
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otherwise. The character between the first pair of slashes is
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as follows:
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"S" The kernel thread is stopped, in other words, all
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CPUs corresponding to this rcu_node structure are
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offline.
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"R" The kernel thread is running.
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"W" The kernel thread is waiting because there is no work
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for it to do.
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"O" The kernel thread is waiting because it has been
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forced off of its designated CPU or because its
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->cpus_allowed mask permits it to run on other than
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its designated CPU.
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"Y" The kernel thread is yielding to avoid hogging CPU.
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"?" Unknown value, indicates a bug.
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The number after the final slash is the CPU that the kthread
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is actually running on.
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This field is displayed only for CONFIG_RCU_BOOST kernels.
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o "ktl" is the low-order 16 bits (in hexadecimal) of the count of
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the number of times that this CPU's per-CPU kthread has gone
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through its loop servicing invoke_rcu_cpu_kthread() requests.
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This field is displayed only for CONFIG_RCU_BOOST kernels.
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The output of "cat rcu/rcu_preempt/rcuexp" looks as follows:
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s=21872 wd1=0 wd2=0 wd3=5 enq=0 sc=21872
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These fields are as follows:
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o "s" is the sequence number, with an odd number indicating that
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an expedited grace period is in progress.
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o "wd1", "wd2", and "wd3" are the number of times that an attempt
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to start an expedited grace period found that someone else had
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completed an expedited grace period that satisfies the attempted
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request. "Our work is done."
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o "enq" is the number of quiescent states still outstanding.
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o "sc" is the number of times that the attempt to start a
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new expedited grace period succeeded.
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The output of "cat rcu/rcu_preempt/rcugp" looks as follows:
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completed=31249 gpnum=31250 age=1 max=18
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These fields are taken from the rcu_state structure, and are as follows:
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o "completed" is the number of grace periods that have completed.
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It is comparable to the "c" field from rcu/rcudata in that a
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CPU whose "c" field matches the value of "completed" is aware
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that the corresponding RCU grace period has completed.
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o "gpnum" is the number of grace periods that have started. It is
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similarly comparable to the "g" field from rcu/rcudata in that
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a CPU whose "g" field matches the value of "gpnum" is aware that
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the corresponding RCU grace period has started.
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If these two fields are equal, then there is no grace period
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in progress, in other words, RCU is idle. On the other hand,
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if the two fields differ (as they are above), then an RCU grace
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period is in progress.
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o "age" is the number of jiffies that the current grace period
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has extended for, or zero if there is no grace period currently
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in effect.
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o "max" is the age in jiffies of the longest-duration grace period
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thus far.
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The output of "cat rcu/rcu_preempt/rcuhier" looks as follows:
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c=14407 g=14408 s=0 jfq=2 j=c863 nfqs=12040/nfqsng=0(12040) fqlh=1051 oqlen=0/0
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3/3 ..>. 0:7 ^0
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e/e ..>. 0:3 ^0 d/d ..>. 4:7 ^1
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The fields are as follows:
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o "c" is exactly the same as "completed" under rcu/rcu_preempt/rcugp.
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o "g" is exactly the same as "gpnum" under rcu/rcu_preempt/rcugp.
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o "s" is the current state of the force_quiescent_state()
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state machine.
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o "jfq" is the number of jiffies remaining for this grace period
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before force_quiescent_state() is invoked to help push things
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along. Note that CPUs in idle mode throughout the grace period
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will not report on their own, but rather must be check by some
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other CPU via force_quiescent_state().
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o "j" is the low-order four hex digits of the jiffies counter.
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Yes, Paul did run into a number of problems that turned out to
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be due to the jiffies counter no longer counting. Why do you ask?
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o "nfqs" is the number of calls to force_quiescent_state() since
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boot.
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o "nfqsng" is the number of useless calls to force_quiescent_state(),
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where there wasn't actually a grace period active. This can
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no longer happen due to grace-period processing being pushed
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into a kthread. The number in parentheses is the difference
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between "nfqs" and "nfqsng", or the number of times that
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force_quiescent_state() actually did some real work.
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o "fqlh" is the number of calls to force_quiescent_state() that
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exited immediately (without even being counted in nfqs above)
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due to contention on ->fqslock.
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o Each element of the form "3/3 ..>. 0:7 ^0" represents one rcu_node
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structure. Each line represents one level of the hierarchy,
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from root to leaves. It is best to think of the rcu_data
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structures as forming yet another level after the leaves.
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Note that there might be either one, two, three, or even four
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levels of rcu_node structures, depending on the relationship
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between CONFIG_RCU_FANOUT, CONFIG_RCU_FANOUT_LEAF (possibly
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adjusted using the rcu_fanout_leaf kernel boot parameter), and
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CONFIG_NR_CPUS (possibly adjusted using the nr_cpu_ids count of
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possible CPUs for the booting hardware).
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o The numbers separated by the "/" are the qsmask followed
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by the qsmaskinit. The qsmask will have one bit
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set for each entity in the next lower level that has
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not yet checked in for the current grace period ("e"
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indicating CPUs 5, 6, and 7 in the example above).
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The qsmaskinit will have one bit for each entity that is
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currently expected to check in during each grace period.
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The value of qsmaskinit is assigned to that of qsmask
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at the beginning of each grace period.
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o The characters separated by the ">" indicate the state
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of the blocked-tasks lists. A "G" preceding the ">"
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indicates that at least one task blocked in an RCU
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read-side critical section blocks the current grace
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period, while a "E" preceding the ">" indicates that
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at least one task blocked in an RCU read-side critical
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section blocks the current expedited grace period.
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A "T" character following the ">" indicates that at
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least one task is blocked within an RCU read-side
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critical section, regardless of whether any current
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grace period (expedited or normal) is inconvenienced.
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A "." character appears if the corresponding condition
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does not hold, so that "..>." indicates that no tasks
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are blocked. In contrast, "GE>T" indicates maximal
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inconvenience from blocked tasks. CONFIG_TREE_RCU
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builds of the kernel will always show "..>.".
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|
||||
o The numbers separated by the ":" are the range of CPUs
|
||||
served by this struct rcu_node. This can be helpful
|
||||
in working out how the hierarchy is wired together.
|
||||
|
||||
For example, the example rcu_node structure shown above
|
||||
has "0:7", indicating that it covers CPUs 0 through 7.
|
||||
|
||||
o The number after the "^" indicates the bit in the
|
||||
next higher level rcu_node structure that this rcu_node
|
||||
structure corresponds to. For example, the "d/d ..>. 4:7
|
||||
^1" has a "1" in this position, indicating that it
|
||||
corresponds to the "1" bit in the "3" shown in the
|
||||
"3/3 ..>. 0:7 ^0" entry on the next level up.
|
||||
|
||||
|
||||
The output of "cat rcu/rcu_sched/rcu_pending" looks as follows:
|
||||
|
||||
0!np=26111 qsp=29 rpq=5386 cbr=1 cng=570 gpc=3674 gps=577 nn=15903 ndw=0
|
||||
1!np=28913 qsp=35 rpq=6097 cbr=1 cng=448 gpc=3700 gps=554 nn=18113 ndw=0
|
||||
2!np=32740 qsp=37 rpq=6202 cbr=0 cng=476 gpc=4627 gps=546 nn=20889 ndw=0
|
||||
3 np=23679 qsp=22 rpq=5044 cbr=1 cng=415 gpc=3403 gps=347 nn=14469 ndw=0
|
||||
4!np=30714 qsp=4 rpq=5574 cbr=0 cng=528 gpc=3931 gps=639 nn=20042 ndw=0
|
||||
5 np=28910 qsp=2 rpq=5246 cbr=0 cng=428 gpc=4105 gps=709 nn=18422 ndw=0
|
||||
6!np=38648 qsp=5 rpq=7076 cbr=0 cng=840 gpc=4072 gps=961 nn=25699 ndw=0
|
||||
7 np=37275 qsp=2 rpq=6873 cbr=0 cng=868 gpc=3416 gps=971 nn=25147 ndw=0
|
||||
|
||||
The fields are as follows:
|
||||
|
||||
o The leading number is the CPU number, with "!" indicating
|
||||
an offline CPU.
|
||||
|
||||
o "np" is the number of times that __rcu_pending() has been invoked
|
||||
for the corresponding flavor of RCU.
|
||||
|
||||
o "qsp" is the number of times that the RCU was waiting for a
|
||||
quiescent state from this CPU.
|
||||
|
||||
o "rpq" is the number of times that the CPU had passed through
|
||||
a quiescent state, but not yet reported it to RCU.
|
||||
|
||||
o "cbr" is the number of times that this CPU had RCU callbacks
|
||||
that had passed through a grace period, and were thus ready
|
||||
to be invoked.
|
||||
|
||||
o "cng" is the number of times that this CPU needed another
|
||||
grace period while RCU was idle.
|
||||
|
||||
o "gpc" is the number of times that an old grace period had
|
||||
completed, but this CPU was not yet aware of it.
|
||||
|
||||
o "gps" is the number of times that a new grace period had started,
|
||||
but this CPU was not yet aware of it.
|
||||
|
||||
o "ndw" is the number of times that a wakeup of an rcuo
|
||||
callback-offload kthread had to be deferred in order to avoid
|
||||
deadlock.
|
||||
|
||||
o "nn" is the number of times that this CPU needed nothing.
|
||||
|
||||
|
||||
The output of "cat rcu/rcuboost" looks as follows:
|
||||
|
||||
0:3 tasks=.... kt=W ntb=0 neb=0 nnb=0 j=c864 bt=c894
|
||||
balk: nt=0 egt=4695 bt=0 nb=0 ny=56 nos=0
|
||||
4:7 tasks=.... kt=W ntb=0 neb=0 nnb=0 j=c864 bt=c894
|
||||
balk: nt=0 egt=6541 bt=0 nb=0 ny=126 nos=0
|
||||
|
||||
This information is output only for rcu_preempt. Each two-line entry
|
||||
corresponds to a leaf rcu_node structure. The fields are as follows:
|
||||
|
||||
o "n:m" is the CPU-number range for the corresponding two-line
|
||||
entry. In the sample output above, the first entry covers
|
||||
CPUs zero through three and the second entry covers CPUs four
|
||||
through seven.
|
||||
|
||||
o "tasks=TNEB" gives the state of the various segments of the
|
||||
rnp->blocked_tasks list:
|
||||
|
||||
"T" This indicates that there are some tasks that blocked
|
||||
while running on one of the corresponding CPUs while
|
||||
in an RCU read-side critical section.
|
||||
|
||||
"N" This indicates that some of the blocked tasks are preventing
|
||||
the current normal (non-expedited) grace period from
|
||||
completing.
|
||||
|
||||
"E" This indicates that some of the blocked tasks are preventing
|
||||
the current expedited grace period from completing.
|
||||
|
||||
"B" This indicates that some of the blocked tasks are in
|
||||
need of RCU priority boosting.
|
||||
|
||||
Each character is replaced with "." if the corresponding
|
||||
condition does not hold.
|
||||
|
||||
o "kt" is the state of the RCU priority-boosting kernel
|
||||
thread associated with the corresponding rcu_node structure.
|
||||
The state can be one of the following:
|
||||
|
||||
"S" The kernel thread is stopped, in other words, all
|
||||
CPUs corresponding to this rcu_node structure are
|
||||
offline.
|
||||
|
||||
"R" The kernel thread is running.
|
||||
|
||||
"W" The kernel thread is waiting because there is no work
|
||||
for it to do.
|
||||
|
||||
"Y" The kernel thread is yielding to avoid hogging CPU.
|
||||
|
||||
"?" Unknown value, indicates a bug.
|
||||
|
||||
o "ntb" is the number of tasks boosted.
|
||||
|
||||
o "neb" is the number of tasks boosted in order to complete an
|
||||
expedited grace period.
|
||||
|
||||
o "nnb" is the number of tasks boosted in order to complete a
|
||||
normal (non-expedited) grace period. When boosting a task
|
||||
that was blocking both an expedited and a normal grace period,
|
||||
it is counted against the expedited total above.
|
||||
|
||||
o "j" is the low-order 16 bits of the jiffies counter in
|
||||
hexadecimal.
|
||||
|
||||
o "bt" is the low-order 16 bits of the value that the jiffies
|
||||
counter will have when we next start boosting, assuming that
|
||||
the current grace period does not end beforehand. This is
|
||||
also in hexadecimal.
|
||||
|
||||
o "balk: nt" counts the number of times we didn't boost (in
|
||||
other words, we balked) even though it was time to boost because
|
||||
there were no blocked tasks to boost. This situation occurs
|
||||
when there is one blocked task on one rcu_node structure and
|
||||
none on some other rcu_node structure.
|
||||
|
||||
o "egt" counts the number of times we balked because although
|
||||
there were blocked tasks, none of them were blocking the
|
||||
current grace period, whether expedited or otherwise.
|
||||
|
||||
o "bt" counts the number of times we balked because boosting
|
||||
had already been initiated for the current grace period.
|
||||
|
||||
o "nb" counts the number of times we balked because there
|
||||
was at least one task blocking the current non-expedited grace
|
||||
period that never had blocked. If it is already running, it
|
||||
just won't help to boost its priority!
|
||||
|
||||
o "ny" counts the number of times we balked because it was
|
||||
not yet time to start boosting.
|
||||
|
||||
o "nos" counts the number of times we balked for other
|
||||
reasons, e.g., the grace period ended first.
|
||||
|
||||
|
||||
CONFIG_TINY_RCU debugfs Files and Formats
|
||||
|
||||
These implementations of RCU provides a single debugfs file under the
|
||||
top-level directory RCU, namely rcu/rcudata, which displays fields in
|
||||
rcu_bh_ctrlblk and rcu_sched_ctrlblk.
|
||||
|
||||
The output of "cat rcu/rcudata" is as follows:
|
||||
|
||||
rcu_sched: qlen: 0
|
||||
rcu_bh: qlen: 0
|
||||
|
||||
This is split into rcu_sched and rcu_bh sections. The field is as
|
||||
follows:
|
||||
|
||||
o "qlen" is the number of RCU callbacks currently waiting either
|
||||
for an RCU grace period or waiting to be invoked. This is the
|
||||
only field present for rcu_sched and rcu_bh, due to the
|
||||
short-circuiting of grace period in those two cases.
|
|
@ -659,14 +659,6 @@ config RCU_FAST_NO_HZ
|
|||
|
||||
Say N if you are unsure.
|
||||
|
||||
config TREE_RCU_TRACE
|
||||
def_bool RCU_TRACE && ( TREE_RCU || PREEMPT_RCU )
|
||||
select DEBUG_FS
|
||||
help
|
||||
This option provides tracing for the TREE_RCU and
|
||||
PREEMPT_RCU implementations, permitting Makefile to
|
||||
trivially select kernel/rcutree_trace.c.
|
||||
|
||||
config RCU_BOOST
|
||||
bool "Enable RCU priority boosting"
|
||||
depends on RT_MUTEXES && PREEMPT_RCU && RCU_EXPERT
|
||||
|
|
|
@ -9,6 +9,5 @@ obj-$(CONFIG_RCU_TORTURE_TEST) += rcutorture.o
|
|||
obj-$(CONFIG_RCU_PERF_TEST) += rcuperf.o
|
||||
obj-$(CONFIG_TREE_RCU) += tree.o
|
||||
obj-$(CONFIG_PREEMPT_RCU) += tree.o
|
||||
obj-$(CONFIG_TREE_RCU_TRACE) += tree_trace.o
|
||||
obj-$(CONFIG_TINY_RCU) += tiny.o
|
||||
obj-$(CONFIG_RCU_NEED_SEGCBLIST) += rcu_segcblist.o
|
||||
|
|
|
@ -24,8 +24,6 @@
|
|||
|
||||
#include <linux/kthread.h>
|
||||
#include <linux/init.h>
|
||||
#include <linux/debugfs.h>
|
||||
#include <linux/seq_file.h>
|
||||
|
||||
/* Global control variables for rcupdate callback mechanism. */
|
||||
struct rcu_ctrlblk {
|
||||
|
@ -87,49 +85,6 @@ static void rcu_trace_sub_qlen(struct rcu_ctrlblk *rcp, int n)
|
|||
local_irq_restore(flags);
|
||||
}
|
||||
|
||||
/*
|
||||
* Dump statistics for TINY_RCU, such as they are.
|
||||
*/
|
||||
static int show_tiny_stats(struct seq_file *m, void *unused)
|
||||
{
|
||||
seq_printf(m, "rcu_sched: qlen: %ld\n", rcu_sched_ctrlblk.qlen);
|
||||
seq_printf(m, "rcu_bh: qlen: %ld\n", rcu_bh_ctrlblk.qlen);
|
||||
return 0;
|
||||
}
|
||||
|
||||
static int show_tiny_stats_open(struct inode *inode, struct file *file)
|
||||
{
|
||||
return single_open(file, show_tiny_stats, NULL);
|
||||
}
|
||||
|
||||
static const struct file_operations show_tiny_stats_fops = {
|
||||
.owner = THIS_MODULE,
|
||||
.open = show_tiny_stats_open,
|
||||
.read = seq_read,
|
||||
.llseek = seq_lseek,
|
||||
.release = single_release,
|
||||
};
|
||||
|
||||
static struct dentry *rcudir;
|
||||
|
||||
static int __init rcutiny_trace_init(void)
|
||||
{
|
||||
struct dentry *retval;
|
||||
|
||||
rcudir = debugfs_create_dir("rcu", NULL);
|
||||
if (!rcudir)
|
||||
goto free_out;
|
||||
retval = debugfs_create_file("rcudata", 0444, rcudir,
|
||||
NULL, &show_tiny_stats_fops);
|
||||
if (!retval)
|
||||
goto free_out;
|
||||
return 0;
|
||||
free_out:
|
||||
debugfs_remove_recursive(rcudir);
|
||||
return 1;
|
||||
}
|
||||
device_initcall(rcutiny_trace_init);
|
||||
|
||||
static void check_cpu_stall(struct rcu_ctrlblk *rcp)
|
||||
{
|
||||
unsigned long j;
|
||||
|
|
|
@ -152,19 +152,6 @@ struct rcu_node {
|
|||
/* Number of tasks boosted for expedited GP. */
|
||||
unsigned long n_normal_boosts;
|
||||
/* Number of tasks boosted for normal GP. */
|
||||
unsigned long n_balk_blkd_tasks;
|
||||
/* Refused to boost: no blocked tasks. */
|
||||
unsigned long n_balk_exp_gp_tasks;
|
||||
/* Refused to boost: nothing blocking GP. */
|
||||
unsigned long n_balk_boost_tasks;
|
||||
/* Refused to boost: already boosting. */
|
||||
unsigned long n_balk_notblocked;
|
||||
/* Refused to boost: RCU RS CS still running. */
|
||||
unsigned long n_balk_notyet;
|
||||
/* Refused to boost: not yet time. */
|
||||
unsigned long n_balk_nos;
|
||||
/* Refused to boost: not sure why, though. */
|
||||
/* This can happen due to race conditions. */
|
||||
#ifdef CONFIG_RCU_NOCB_CPU
|
||||
struct swait_queue_head nocb_gp_wq[2];
|
||||
/* Place for rcu_nocb_kthread() to wait GP. */
|
||||
|
@ -535,17 +522,3 @@ void srcu_offline_cpu(unsigned int cpu) { }
|
|||
#endif /* #else #ifdef CONFIG_SRCU */
|
||||
|
||||
#endif /* #ifndef RCU_TREE_NONCORE */
|
||||
|
||||
#ifdef CONFIG_RCU_TRACE
|
||||
/* Read out queue lengths for tracing. */
|
||||
static inline void rcu_nocb_q_lengths(struct rcu_data *rdp, long *ql, long *qll)
|
||||
{
|
||||
#ifdef CONFIG_RCU_NOCB_CPU
|
||||
*ql = atomic_long_read(&rdp->nocb_q_count);
|
||||
*qll = atomic_long_read(&rdp->nocb_q_count_lazy);
|
||||
#else /* #ifdef CONFIG_RCU_NOCB_CPU */
|
||||
*ql = 0;
|
||||
*qll = 0;
|
||||
#endif /* #else #ifdef CONFIG_RCU_NOCB_CPU */
|
||||
}
|
||||
#endif /* #ifdef CONFIG_RCU_TRACE */
|
||||
|
|
|
@ -70,7 +70,7 @@ static bool __read_mostly rcu_nocb_poll; /* Offload kthread are to poll. */
|
|||
static void __init rcu_bootup_announce_oddness(void)
|
||||
{
|
||||
if (IS_ENABLED(CONFIG_RCU_TRACE))
|
||||
pr_info("\tRCU debugfs-based tracing is enabled.\n");
|
||||
pr_info("\tRCU event tracing is enabled.\n");
|
||||
if ((IS_ENABLED(CONFIG_64BIT) && RCU_FANOUT != 64) ||
|
||||
(!IS_ENABLED(CONFIG_64BIT) && RCU_FANOUT != 32))
|
||||
pr_info("\tCONFIG_RCU_FANOUT set to non-default value of %d\n",
|
||||
|
@ -899,33 +899,6 @@ void exit_rcu(void)
|
|||
|
||||
#include "../locking/rtmutex_common.h"
|
||||
|
||||
#ifdef CONFIG_RCU_TRACE
|
||||
|
||||
static void rcu_initiate_boost_trace(struct rcu_node *rnp)
|
||||
{
|
||||
if (!rcu_preempt_has_tasks(rnp))
|
||||
rnp->n_balk_blkd_tasks++;
|
||||
else if (rnp->exp_tasks == NULL && rnp->gp_tasks == NULL)
|
||||
rnp->n_balk_exp_gp_tasks++;
|
||||
else if (rnp->gp_tasks != NULL && rnp->boost_tasks != NULL)
|
||||
rnp->n_balk_boost_tasks++;
|
||||
else if (rnp->gp_tasks != NULL && rnp->qsmask != 0)
|
||||
rnp->n_balk_notblocked++;
|
||||
else if (rnp->gp_tasks != NULL &&
|
||||
ULONG_CMP_LT(jiffies, rnp->boost_time))
|
||||
rnp->n_balk_notyet++;
|
||||
else
|
||||
rnp->n_balk_nos++;
|
||||
}
|
||||
|
||||
#else /* #ifdef CONFIG_RCU_TRACE */
|
||||
|
||||
static void rcu_initiate_boost_trace(struct rcu_node *rnp)
|
||||
{
|
||||
}
|
||||
|
||||
#endif /* #else #ifdef CONFIG_RCU_TRACE */
|
||||
|
||||
static void rcu_wake_cond(struct task_struct *t, int status)
|
||||
{
|
||||
/*
|
||||
|
@ -1058,7 +1031,6 @@ static void rcu_initiate_boost(struct rcu_node *rnp, unsigned long flags)
|
|||
|
||||
lockdep_assert_held(&rnp->lock);
|
||||
if (!rcu_preempt_blocked_readers_cgp(rnp) && rnp->exp_tasks == NULL) {
|
||||
rnp->n_balk_exp_gp_tasks++;
|
||||
raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
|
||||
return;
|
||||
}
|
||||
|
@ -1074,7 +1046,6 @@ static void rcu_initiate_boost(struct rcu_node *rnp, unsigned long flags)
|
|||
if (t)
|
||||
rcu_wake_cond(t, rnp->boost_kthread_status);
|
||||
} else {
|
||||
rcu_initiate_boost_trace(rnp);
|
||||
raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
|
||||
}
|
||||
}
|
||||
|
|
|
@ -1,494 +0,0 @@
|
|||
/*
|
||||
* Read-Copy Update tracing for hierarchical implementation.
|
||||
*
|
||||
* This program is free software; you can redistribute it and/or modify
|
||||
* it under the terms of the GNU General Public License as published by
|
||||
* the Free Software Foundation; either version 2 of the License, or
|
||||
* (at your option) any later version.
|
||||
*
|
||||
* This program is distributed in the hope that it will be useful,
|
||||
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||||
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
||||
* GNU General Public License for more details.
|
||||
*
|
||||
* You should have received a copy of the GNU General Public License
|
||||
* along with this program; if not, you can access it online at
|
||||
* http://www.gnu.org/licenses/gpl-2.0.html.
|
||||
*
|
||||
* Copyright IBM Corporation, 2008
|
||||
* Author: Paul E. McKenney
|
||||
*
|
||||
* Papers: http://www.rdrop.com/users/paulmck/RCU
|
||||
*
|
||||
* For detailed explanation of Read-Copy Update mechanism see -
|
||||
* Documentation/RCU
|
||||
*
|
||||
*/
|
||||
#include <linux/types.h>
|
||||
#include <linux/kernel.h>
|
||||
#include <linux/init.h>
|
||||
#include <linux/spinlock.h>
|
||||
#include <linux/smp.h>
|
||||
#include <linux/rcupdate.h>
|
||||
#include <linux/interrupt.h>
|
||||
#include <linux/sched.h>
|
||||
#include <linux/atomic.h>
|
||||
#include <linux/bitops.h>
|
||||
#include <linux/completion.h>
|
||||
#include <linux/percpu.h>
|
||||
#include <linux/notifier.h>
|
||||
#include <linux/cpu.h>
|
||||
#include <linux/mutex.h>
|
||||
#include <linux/debugfs.h>
|
||||
#include <linux/seq_file.h>
|
||||
#include <linux/prefetch.h>
|
||||
|
||||
#define RCU_TREE_NONCORE
|
||||
#include "tree.h"
|
||||
#include "rcu.h"
|
||||
|
||||
static int r_open(struct inode *inode, struct file *file,
|
||||
const struct seq_operations *op)
|
||||
{
|
||||
int ret = seq_open(file, op);
|
||||
if (!ret) {
|
||||
struct seq_file *m = (struct seq_file *)file->private_data;
|
||||
m->private = inode->i_private;
|
||||
}
|
||||
return ret;
|
||||
}
|
||||
|
||||
static void *r_start(struct seq_file *m, loff_t *pos)
|
||||
{
|
||||
struct rcu_state *rsp = (struct rcu_state *)m->private;
|
||||
*pos = cpumask_next(*pos - 1, cpu_possible_mask);
|
||||
if ((*pos) < nr_cpu_ids)
|
||||
return per_cpu_ptr(rsp->rda, *pos);
|
||||
return NULL;
|
||||
}
|
||||
|
||||
static void *r_next(struct seq_file *m, void *v, loff_t *pos)
|
||||
{
|
||||
(*pos)++;
|
||||
return r_start(m, pos);
|
||||
}
|
||||
|
||||
static void r_stop(struct seq_file *m, void *v)
|
||||
{
|
||||
}
|
||||
|
||||
static int show_rcubarrier(struct seq_file *m, void *v)
|
||||
{
|
||||
struct rcu_state *rsp = (struct rcu_state *)m->private;
|
||||
seq_printf(m, "bcc: %d bseq: %lu\n",
|
||||
atomic_read(&rsp->barrier_cpu_count),
|
||||
rsp->barrier_sequence);
|
||||
return 0;
|
||||
}
|
||||
|
||||
static int rcubarrier_open(struct inode *inode, struct file *file)
|
||||
{
|
||||
return single_open(file, show_rcubarrier, inode->i_private);
|
||||
}
|
||||
|
||||
static const struct file_operations rcubarrier_fops = {
|
||||
.owner = THIS_MODULE,
|
||||
.open = rcubarrier_open,
|
||||
.read = seq_read,
|
||||
.llseek = no_llseek,
|
||||
.release = single_release,
|
||||
};
|
||||
|
||||
#ifdef CONFIG_RCU_BOOST
|
||||
|
||||
static char convert_kthread_status(unsigned int kthread_status)
|
||||
{
|
||||
if (kthread_status > RCU_KTHREAD_MAX)
|
||||
return '?';
|
||||
return "SRWOY"[kthread_status];
|
||||
}
|
||||
|
||||
#endif /* #ifdef CONFIG_RCU_BOOST */
|
||||
|
||||
static void print_one_rcu_data(struct seq_file *m, struct rcu_data *rdp)
|
||||
{
|
||||
long ql, qll;
|
||||
|
||||
if (!rdp->beenonline)
|
||||
return;
|
||||
seq_printf(m, "%3d%cc=%ld g=%ld cnq=%d/%d:%d",
|
||||
rdp->cpu,
|
||||
cpu_is_offline(rdp->cpu) ? '!' : ' ',
|
||||
ulong2long(rdp->completed), ulong2long(rdp->gpnum),
|
||||
rdp->cpu_no_qs.b.norm,
|
||||
rdp->rcu_qs_ctr_snap == per_cpu(rdp->dynticks->rcu_qs_ctr, rdp->cpu),
|
||||
rdp->core_needs_qs);
|
||||
seq_printf(m, " dt=%d/%llx/%d df=%lu",
|
||||
rcu_dynticks_snap(rdp->dynticks),
|
||||
rdp->dynticks->dynticks_nesting,
|
||||
rdp->dynticks->dynticks_nmi_nesting,
|
||||
rdp->dynticks_fqs);
|
||||
seq_printf(m, " of=%lu", rdp->offline_fqs);
|
||||
rcu_nocb_q_lengths(rdp, &ql, &qll);
|
||||
qll += rcu_segcblist_n_lazy_cbs(&rdp->cblist);
|
||||
ql += rcu_segcblist_n_cbs(&rdp->cblist);
|
||||
seq_printf(m, " ql=%ld/%ld qs=%c%c%c%c",
|
||||
qll, ql,
|
||||
".N"[!rcu_segcblist_segempty(&rdp->cblist, RCU_NEXT_TAIL)],
|
||||
".R"[!rcu_segcblist_segempty(&rdp->cblist,
|
||||
RCU_NEXT_READY_TAIL)],
|
||||
".W"[!rcu_segcblist_segempty(&rdp->cblist, RCU_WAIT_TAIL)],
|
||||
".D"[!rcu_segcblist_segempty(&rdp->cblist, RCU_DONE_TAIL)]);
|
||||
#ifdef CONFIG_RCU_BOOST
|
||||
seq_printf(m, " kt=%d/%c ktl=%x",
|
||||
per_cpu(rcu_cpu_has_work, rdp->cpu),
|
||||
convert_kthread_status(per_cpu(rcu_cpu_kthread_status,
|
||||
rdp->cpu)),
|
||||
per_cpu(rcu_cpu_kthread_loops, rdp->cpu) & 0xffff);
|
||||
#endif /* #ifdef CONFIG_RCU_BOOST */
|
||||
seq_printf(m, " b=%ld", rdp->blimit);
|
||||
seq_printf(m, " ci=%lu nci=%lu co=%lu ca=%lu\n",
|
||||
rdp->n_cbs_invoked, rdp->n_nocbs_invoked,
|
||||
rdp->n_cbs_orphaned, rdp->n_cbs_adopted);
|
||||
}
|
||||
|
||||
static int show_rcudata(struct seq_file *m, void *v)
|
||||
{
|
||||
print_one_rcu_data(m, (struct rcu_data *)v);
|
||||
return 0;
|
||||
}
|
||||
|
||||
static const struct seq_operations rcudate_op = {
|
||||
.start = r_start,
|
||||
.next = r_next,
|
||||
.stop = r_stop,
|
||||
.show = show_rcudata,
|
||||
};
|
||||
|
||||
static int rcudata_open(struct inode *inode, struct file *file)
|
||||
{
|
||||
return r_open(inode, file, &rcudate_op);
|
||||
}
|
||||
|
||||
static const struct file_operations rcudata_fops = {
|
||||
.owner = THIS_MODULE,
|
||||
.open = rcudata_open,
|
||||
.read = seq_read,
|
||||
.llseek = no_llseek,
|
||||
.release = seq_release,
|
||||
};
|
||||
|
||||
static int show_rcuexp(struct seq_file *m, void *v)
|
||||
{
|
||||
int cpu;
|
||||
struct rcu_state *rsp = (struct rcu_state *)m->private;
|
||||
struct rcu_data *rdp;
|
||||
unsigned long s0 = 0, s1 = 0, s2 = 0, s3 = 0;
|
||||
|
||||
for_each_possible_cpu(cpu) {
|
||||
rdp = per_cpu_ptr(rsp->rda, cpu);
|
||||
s0 += atomic_long_read(&rdp->exp_workdone0);
|
||||
s1 += atomic_long_read(&rdp->exp_workdone1);
|
||||
s2 += atomic_long_read(&rdp->exp_workdone2);
|
||||
s3 += atomic_long_read(&rdp->exp_workdone3);
|
||||
}
|
||||
seq_printf(m, "s=%lu wd0=%lu wd1=%lu wd2=%lu wd3=%lu enq=%d sc=%lu\n",
|
||||
rsp->expedited_sequence, s0, s1, s2, s3,
|
||||
atomic_read(&rsp->expedited_need_qs),
|
||||
rsp->expedited_sequence / 2);
|
||||
return 0;
|
||||
}
|
||||
|
||||
static int rcuexp_open(struct inode *inode, struct file *file)
|
||||
{
|
||||
return single_open(file, show_rcuexp, inode->i_private);
|
||||
}
|
||||
|
||||
static const struct file_operations rcuexp_fops = {
|
||||
.owner = THIS_MODULE,
|
||||
.open = rcuexp_open,
|
||||
.read = seq_read,
|
||||
.llseek = no_llseek,
|
||||
.release = single_release,
|
||||
};
|
||||
|
||||
#ifdef CONFIG_RCU_BOOST
|
||||
|
||||
static void print_one_rcu_node_boost(struct seq_file *m, struct rcu_node *rnp)
|
||||
{
|
||||
seq_printf(m, "%d:%d tasks=%c%c%c%c kt=%c ntb=%lu neb=%lu nnb=%lu ",
|
||||
rnp->grplo, rnp->grphi,
|
||||
"T."[list_empty(&rnp->blkd_tasks)],
|
||||
"N."[!rnp->gp_tasks],
|
||||
"E."[!rnp->exp_tasks],
|
||||
"B."[!rnp->boost_tasks],
|
||||
convert_kthread_status(rnp->boost_kthread_status),
|
||||
rnp->n_tasks_boosted, rnp->n_exp_boosts,
|
||||
rnp->n_normal_boosts);
|
||||
seq_printf(m, "j=%04x bt=%04x\n",
|
||||
(int)(jiffies & 0xffff),
|
||||
(int)(rnp->boost_time & 0xffff));
|
||||
seq_printf(m, " balk: nt=%lu egt=%lu bt=%lu nb=%lu ny=%lu nos=%lu\n",
|
||||
rnp->n_balk_blkd_tasks,
|
||||
rnp->n_balk_exp_gp_tasks,
|
||||
rnp->n_balk_boost_tasks,
|
||||
rnp->n_balk_notblocked,
|
||||
rnp->n_balk_notyet,
|
||||
rnp->n_balk_nos);
|
||||
}
|
||||
|
||||
static int show_rcu_node_boost(struct seq_file *m, void *unused)
|
||||
{
|
||||
struct rcu_node *rnp;
|
||||
|
||||
rcu_for_each_leaf_node(&rcu_preempt_state, rnp)
|
||||
print_one_rcu_node_boost(m, rnp);
|
||||
return 0;
|
||||
}
|
||||
|
||||
static int rcu_node_boost_open(struct inode *inode, struct file *file)
|
||||
{
|
||||
return single_open(file, show_rcu_node_boost, NULL);
|
||||
}
|
||||
|
||||
static const struct file_operations rcu_node_boost_fops = {
|
||||
.owner = THIS_MODULE,
|
||||
.open = rcu_node_boost_open,
|
||||
.read = seq_read,
|
||||
.llseek = no_llseek,
|
||||
.release = single_release,
|
||||
};
|
||||
|
||||
#endif /* #ifdef CONFIG_RCU_BOOST */
|
||||
|
||||
static void print_one_rcu_state(struct seq_file *m, struct rcu_state *rsp)
|
||||
{
|
||||
unsigned long gpnum;
|
||||
int level = 0;
|
||||
struct rcu_node *rnp;
|
||||
|
||||
gpnum = rsp->gpnum;
|
||||
seq_printf(m, "c=%ld g=%ld s=%d jfq=%ld j=%x ",
|
||||
ulong2long(rsp->completed), ulong2long(gpnum),
|
||||
rsp->gp_state,
|
||||
(long)(rsp->jiffies_force_qs - jiffies),
|
||||
(int)(jiffies & 0xffff));
|
||||
seq_printf(m, "nfqs=%lu/nfqsng=%lu(%lu) fqlh=%lu oqlen=%ld/%ld\n",
|
||||
rsp->n_force_qs, rsp->n_force_qs_ngp,
|
||||
rsp->n_force_qs - rsp->n_force_qs_ngp,
|
||||
READ_ONCE(rsp->n_force_qs_lh),
|
||||
rsp->orphan_done.len_lazy,
|
||||
rsp->orphan_done.len);
|
||||
for (rnp = &rsp->node[0]; rnp - &rsp->node[0] < rcu_num_nodes; rnp++) {
|
||||
if (rnp->level != level) {
|
||||
seq_puts(m, "\n");
|
||||
level = rnp->level;
|
||||
}
|
||||
seq_printf(m, "%lx/%lx->%lx %c%c>%c %d:%d ^%d ",
|
||||
rnp->qsmask, rnp->qsmaskinit, rnp->qsmaskinitnext,
|
||||
".G"[rnp->gp_tasks != NULL],
|
||||
".E"[rnp->exp_tasks != NULL],
|
||||
".T"[!list_empty(&rnp->blkd_tasks)],
|
||||
rnp->grplo, rnp->grphi, rnp->grpnum);
|
||||
}
|
||||
seq_puts(m, "\n");
|
||||
}
|
||||
|
||||
static int show_rcuhier(struct seq_file *m, void *v)
|
||||
{
|
||||
struct rcu_state *rsp = (struct rcu_state *)m->private;
|
||||
print_one_rcu_state(m, rsp);
|
||||
return 0;
|
||||
}
|
||||
|
||||
static int rcuhier_open(struct inode *inode, struct file *file)
|
||||
{
|
||||
return single_open(file, show_rcuhier, inode->i_private);
|
||||
}
|
||||
|
||||
static const struct file_operations rcuhier_fops = {
|
||||
.owner = THIS_MODULE,
|
||||
.open = rcuhier_open,
|
||||
.read = seq_read,
|
||||
.llseek = no_llseek,
|
||||
.release = single_release,
|
||||
};
|
||||
|
||||
static void show_one_rcugp(struct seq_file *m, struct rcu_state *rsp)
|
||||
{
|
||||
unsigned long flags;
|
||||
unsigned long completed;
|
||||
unsigned long gpnum;
|
||||
unsigned long gpage;
|
||||
unsigned long gpmax;
|
||||
struct rcu_node *rnp = &rsp->node[0];
|
||||
|
||||
raw_spin_lock_irqsave_rcu_node(rnp, flags);
|
||||
completed = READ_ONCE(rsp->completed);
|
||||
gpnum = READ_ONCE(rsp->gpnum);
|
||||
if (completed == gpnum)
|
||||
gpage = 0;
|
||||
else
|
||||
gpage = jiffies - rsp->gp_start;
|
||||
gpmax = rsp->gp_max;
|
||||
raw_spin_unlock_irqrestore(&rnp->lock, flags);
|
||||
seq_printf(m, "completed=%ld gpnum=%ld age=%ld max=%ld\n",
|
||||
ulong2long(completed), ulong2long(gpnum), gpage, gpmax);
|
||||
}
|
||||
|
||||
static int show_rcugp(struct seq_file *m, void *v)
|
||||
{
|
||||
struct rcu_state *rsp = (struct rcu_state *)m->private;
|
||||
show_one_rcugp(m, rsp);
|
||||
return 0;
|
||||
}
|
||||
|
||||
static int rcugp_open(struct inode *inode, struct file *file)
|
||||
{
|
||||
return single_open(file, show_rcugp, inode->i_private);
|
||||
}
|
||||
|
||||
static const struct file_operations rcugp_fops = {
|
||||
.owner = THIS_MODULE,
|
||||
.open = rcugp_open,
|
||||
.read = seq_read,
|
||||
.llseek = no_llseek,
|
||||
.release = single_release,
|
||||
};
|
||||
|
||||
static void print_one_rcu_pending(struct seq_file *m, struct rcu_data *rdp)
|
||||
{
|
||||
if (!rdp->beenonline)
|
||||
return;
|
||||
seq_printf(m, "%3d%cnp=%ld ",
|
||||
rdp->cpu,
|
||||
cpu_is_offline(rdp->cpu) ? '!' : ' ',
|
||||
rdp->n_rcu_pending);
|
||||
seq_printf(m, "qsp=%ld rpq=%ld cbr=%ld cng=%ld ",
|
||||
rdp->n_rp_core_needs_qs,
|
||||
rdp->n_rp_report_qs,
|
||||
rdp->n_rp_cb_ready,
|
||||
rdp->n_rp_cpu_needs_gp);
|
||||
seq_printf(m, "gpc=%ld gps=%ld nn=%ld ndw%ld\n",
|
||||
rdp->n_rp_gp_completed,
|
||||
rdp->n_rp_gp_started,
|
||||
rdp->n_rp_nocb_defer_wakeup,
|
||||
rdp->n_rp_need_nothing);
|
||||
}
|
||||
|
||||
static int show_rcu_pending(struct seq_file *m, void *v)
|
||||
{
|
||||
print_one_rcu_pending(m, (struct rcu_data *)v);
|
||||
return 0;
|
||||
}
|
||||
|
||||
static const struct seq_operations rcu_pending_op = {
|
||||
.start = r_start,
|
||||
.next = r_next,
|
||||
.stop = r_stop,
|
||||
.show = show_rcu_pending,
|
||||
};
|
||||
|
||||
static int rcu_pending_open(struct inode *inode, struct file *file)
|
||||
{
|
||||
return r_open(inode, file, &rcu_pending_op);
|
||||
}
|
||||
|
||||
static const struct file_operations rcu_pending_fops = {
|
||||
.owner = THIS_MODULE,
|
||||
.open = rcu_pending_open,
|
||||
.read = seq_read,
|
||||
.llseek = no_llseek,
|
||||
.release = seq_release,
|
||||
};
|
||||
|
||||
static int show_rcutorture(struct seq_file *m, void *unused)
|
||||
{
|
||||
seq_printf(m, "rcutorture test sequence: %lu %s\n",
|
||||
rcutorture_testseq >> 1,
|
||||
(rcutorture_testseq & 0x1) ? "(test in progress)" : "");
|
||||
seq_printf(m, "rcutorture update version number: %lu\n",
|
||||
rcutorture_vernum);
|
||||
return 0;
|
||||
}
|
||||
|
||||
static int rcutorture_open(struct inode *inode, struct file *file)
|
||||
{
|
||||
return single_open(file, show_rcutorture, NULL);
|
||||
}
|
||||
|
||||
static const struct file_operations rcutorture_fops = {
|
||||
.owner = THIS_MODULE,
|
||||
.open = rcutorture_open,
|
||||
.read = seq_read,
|
||||
.llseek = seq_lseek,
|
||||
.release = single_release,
|
||||
};
|
||||
|
||||
static struct dentry *rcudir;
|
||||
|
||||
static int __init rcutree_trace_init(void)
|
||||
{
|
||||
struct rcu_state *rsp;
|
||||
struct dentry *retval;
|
||||
struct dentry *rspdir;
|
||||
|
||||
rcudir = debugfs_create_dir("rcu", NULL);
|
||||
if (!rcudir)
|
||||
goto free_out;
|
||||
|
||||
for_each_rcu_flavor(rsp) {
|
||||
rspdir = debugfs_create_dir(rsp->name, rcudir);
|
||||
if (!rspdir)
|
||||
goto free_out;
|
||||
|
||||
retval = debugfs_create_file("rcudata", 0444,
|
||||
rspdir, rsp, &rcudata_fops);
|
||||
if (!retval)
|
||||
goto free_out;
|
||||
|
||||
retval = debugfs_create_file("rcuexp", 0444,
|
||||
rspdir, rsp, &rcuexp_fops);
|
||||
if (!retval)
|
||||
goto free_out;
|
||||
|
||||
retval = debugfs_create_file("rcu_pending", 0444,
|
||||
rspdir, rsp, &rcu_pending_fops);
|
||||
if (!retval)
|
||||
goto free_out;
|
||||
|
||||
retval = debugfs_create_file("rcubarrier", 0444,
|
||||
rspdir, rsp, &rcubarrier_fops);
|
||||
if (!retval)
|
||||
goto free_out;
|
||||
|
||||
#ifdef CONFIG_RCU_BOOST
|
||||
if (rsp == &rcu_preempt_state) {
|
||||
retval = debugfs_create_file("rcuboost", 0444,
|
||||
rspdir, NULL, &rcu_node_boost_fops);
|
||||
if (!retval)
|
||||
goto free_out;
|
||||
}
|
||||
#endif
|
||||
|
||||
retval = debugfs_create_file("rcugp", 0444,
|
||||
rspdir, rsp, &rcugp_fops);
|
||||
if (!retval)
|
||||
goto free_out;
|
||||
|
||||
retval = debugfs_create_file("rcuhier", 0444,
|
||||
rspdir, rsp, &rcuhier_fops);
|
||||
if (!retval)
|
||||
goto free_out;
|
||||
}
|
||||
|
||||
retval = debugfs_create_file("rcutorture", 0444, rcudir,
|
||||
NULL, &rcutorture_fops);
|
||||
if (!retval)
|
||||
goto free_out;
|
||||
return 0;
|
||||
free_out:
|
||||
debugfs_remove_recursive(rcudir);
|
||||
return 1;
|
||||
}
|
||||
device_initcall(rcutree_trace_init);
|
|
@ -1361,9 +1361,8 @@ config RCU_TRACE
|
|||
default y if TREE_RCU
|
||||
select TRACE_CLOCK
|
||||
help
|
||||
This option provides tracing in RCU which presents stats
|
||||
in debugfs for debugging RCU implementation. It also enables
|
||||
additional tracepoints for ftrace-style event tracing.
|
||||
This option enables additional tracepoints for ftrace-style
|
||||
event tracing.
|
||||
|
||||
Say Y here if you want to enable RCU tracing
|
||||
Say N if you are unsure.
|
||||
|
|
|
@ -1,21 +0,0 @@
|
|||
CONFIG_SMP=y
|
||||
CONFIG_NR_CPUS=8
|
||||
CONFIG_PREEMPT_NONE=n
|
||||
CONFIG_PREEMPT_VOLUNTARY=n
|
||||
CONFIG_PREEMPT=y
|
||||
#CHECK#CONFIG_PREEMPT_RCU=y
|
||||
CONFIG_HZ_PERIODIC=n
|
||||
CONFIG_NO_HZ_IDLE=y
|
||||
CONFIG_NO_HZ_FULL=n
|
||||
CONFIG_RCU_FAST_NO_HZ=n
|
||||
CONFIG_RCU_TRACE=y
|
||||
CONFIG_HOTPLUG_CPU=n
|
||||
CONFIG_SUSPEND=n
|
||||
CONFIG_HIBERNATION=n
|
||||
CONFIG_RCU_FANOUT=3
|
||||
CONFIG_RCU_FANOUT_LEAF=3
|
||||
CONFIG_RCU_NOCB_CPU=n
|
||||
CONFIG_DEBUG_LOCK_ALLOC=y
|
||||
CONFIG_PROVE_LOCKING=n
|
||||
CONFIG_RCU_BOOST=n
|
||||
CONFIG_DEBUG_OBJECTS_RCU_HEAD=n
|
|
@ -1,21 +0,0 @@
|
|||
CONFIG_SMP=y
|
||||
CONFIG_NR_CPUS=16
|
||||
CONFIG_PREEMPT_NONE=n
|
||||
CONFIG_PREEMPT_VOLUNTARY=n
|
||||
CONFIG_PREEMPT=y
|
||||
#CHECK#CONFIG_PREEMPT_RCU=y
|
||||
CONFIG_HZ_PERIODIC=n
|
||||
CONFIG_NO_HZ_IDLE=y
|
||||
CONFIG_NO_HZ_FULL=n
|
||||
CONFIG_RCU_FAST_NO_HZ=n
|
||||
CONFIG_RCU_TRACE=y
|
||||
CONFIG_HOTPLUG_CPU=n
|
||||
CONFIG_SUSPEND=n
|
||||
CONFIG_HIBERNATION=n
|
||||
CONFIG_RCU_FANOUT=3
|
||||
CONFIG_RCU_FANOUT_LEAF=2
|
||||
CONFIG_RCU_NOCB_CPU=y
|
||||
CONFIG_RCU_NOCB_CPU_ALL=y
|
||||
CONFIG_DEBUG_LOCK_ALLOC=n
|
||||
CONFIG_RCU_BOOST=n
|
||||
CONFIG_DEBUG_OBJECTS_RCU_HEAD=n
|
|
@ -79,9 +79,5 @@ CONFIG_TASKS_RCU
|
|||
|
||||
Selected by CONFIG_RCU_TORTURE_TEST, so cannot disable.
|
||||
|
||||
CONFIG_RCU_TRACE
|
||||
|
||||
Implied by CONFIG_RCU_TRACE for Tree RCU.
|
||||
|
||||
|
||||
boot parameters ignored: TBD
|
||||
|
|
Loading…
Reference in a new issue