| Age | Commit message (Collapse) | Author | Files | Lines |
|---|
|
This commit sets SEGCBLIST_SOFTIRQ_ONLY once toggling is otherwise fully
complete, allowing further RCU callback manipulation to be carried out
locklessly and locally.
Cc: Josh Triplett <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Mathieu Desnoyers <[email protected]>
Cc: Lai Jiangshan <[email protected]>
Cc: Joel Fernandes <[email protected]>
Cc: Neeraj Upadhyay <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Inspired-by: Paul E. McKenney <[email protected]>
Tested-by: Boqun Feng <[email protected]>
Signed-off-by: Frederic Weisbecker <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>
|
|
This commit flushes the bypass queue and sets state to avoid its being
refilled before switching to the final de-offloaded state. To avoid
refilling, this commit sets SEGCBLIST_SOFTIRQ_ONLY before re-enabling
IRQs.
Cc: Josh Triplett <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Mathieu Desnoyers <[email protected]>
Cc: Lai Jiangshan <[email protected]>
Cc: Joel Fernandes <[email protected]>
Cc: Neeraj Upadhyay <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Inspired-by: Paul E. McKenney <[email protected]>
Tested-by: Boqun Feng <[email protected]>
Signed-off-by: Frederic Weisbecker <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>
|
|
This commit ensures that the nocb timer is shut down before reaching the
final de-offloaded state. The key goal is to prevent the timer handler
from manipulating the callbacks without the protection of the nocb locks.
Cc: Josh Triplett <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Mathieu Desnoyers <[email protected]>
Cc: Lai Jiangshan <[email protected]>
Cc: Joel Fernandes <[email protected]>
Cc: Neeraj Upadhyay <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Inspired-by: Paul E. McKenney <[email protected]>
Tested-by: Boqun Feng <[email protected]>
Signed-off-by: Frederic Weisbecker <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>
|
|
To re-offload the callback processing off of a CPU, it is necessary to
clear SEGCBLIST_SOFTIRQ_ONLY, set SEGCBLIST_OFFLOADED, and then notify
both the CB and GP kthreads so that they both set their own bit flag and
start processing the callbacks remotely. The re-offloading worker is
then notified that it can stop the RCU_SOFTIRQ handler (or rcuc kthread,
as the case may be) from processing the callbacks locally.
Ordering must be carefully enforced so that the callbacks that used to be
processed locally without locking will have the same ordering properties
when they are invoked by the nocb CB and GP kthreads.
This commit makes this change.
Cc: Josh Triplett <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Mathieu Desnoyers <[email protected]>
Cc: Lai Jiangshan <[email protected]>
Cc: Joel Fernandes <[email protected]>
Cc: Neeraj Upadhyay <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Inspired-by: Paul E. McKenney <[email protected]>
Tested-by: Boqun Feng <[email protected]>
Signed-off-by: Frederic Weisbecker <[email protected]>
[ paulmck: Export rcu_nocb_cpu_offload(). ]
Signed-off-by: Paul E. McKenney <[email protected]>
|
|
To de-offload callback processing back onto a CPU, it is necessary
to clear SEGCBLIST_OFFLOAD and notify the nocb GP kthread, which will
then clear its own bit flag and ignore this CPU until further notice.
Whichever of the nocb CB and nocb GP kthreads is last to clear its own
bit notifies the de-offloading worker kthread. Once notified, this
worker kthread can proceed safe in the knowledge that the nocb CB and
GP kthreads will no longer be manipulating this CPU's RCU callback list.
This commit makes this change.
Cc: Josh Triplett <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Mathieu Desnoyers <[email protected]>
Cc: Lai Jiangshan <[email protected]>
Cc: Joel Fernandes <[email protected]>
Cc: Neeraj Upadhyay <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Inspired-by: Paul E. McKenney <[email protected]>
Tested-by: Boqun Feng <[email protected]>
Signed-off-by: Frederic Weisbecker <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>
|
|
Offloaded CPUs do not migrate their callbacks, instead relying on
their rcuo kthread to invoke them. But if the CPU is offline, it
will be running neither its RCU_SOFTIRQ handler nor its rcuc kthread.
This means that de-offloading an offline CPU that still has pending
callbacks will strand those callbacks. This commit therefore refuses
to toggle offline CPUs having pending callbacks.
Cc: Josh Triplett <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Mathieu Desnoyers <[email protected]>
Cc: Lai Jiangshan <[email protected]>
Cc: Joel Fernandes <[email protected]>
Cc: Neeraj Upadhyay <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Suggested-by: Paul E. McKenney <[email protected]>
Tested-by: Boqun Feng <[email protected]>
Signed-off-by: Frederic Weisbecker <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>
|
|
To de-offload callback processing back onto a CPU, it is necessary to
clear SEGCBLIST_OFFLOAD and notify the nocb CB kthread, which will then
clear its own bit flag and go to sleep to stop handling callbacks. This
commit makes that change. It will also be necessary to notify the nocb
GP kthread in this same way, which is the subject of a follow-on commit.
Cc: Josh Triplett <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Mathieu Desnoyers <[email protected]>
Cc: Lai Jiangshan <[email protected]>
Cc: Joel Fernandes <[email protected]>
Cc: Neeraj Upadhyay <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Inspired-by: Paul E. McKenney <[email protected]>
Tested-by: Boqun Feng <[email protected]>
Signed-off-by: Frederic Weisbecker <[email protected]>
[ paulmck: Add export per kernel test robot feedback. ]
Signed-off-by: Paul E. McKenney <[email protected]>
|
|
How the rdp->cblist enabled state is treated at CPU-hotplug time depends
on whether or not that ->cblist is offloaded.
1) Not offloaded: The ->cblist is disabled when the CPU goes down. All
its callbacks are migrated and none can to enqueued until after some
later CPU-hotplug operation brings the CPU back up.
2) Offloaded: The ->cblist is not disabled on CPU down because the CB/GP
kthreads must finish invoking the remaining callbacks. There is thus
no need to re-enable it on CPU up.
Since the ->cblist offloaded state is set in stone at boot, it cannot
change between CPU down and CPU up. So 1) and 2) are symmetrical.
However, given runtime toggling of the offloaded state, there are two
additional asymmetrical scenarios:
3) The ->cblist is not offloaded when the CPU goes down. The ->cblist
is later toggled to offloaded and then the CPU comes back up.
4) The ->cblist is offloaded when the CPU goes down. The ->cblist is
later toggled to no longer be offloaded and then the CPU comes back up.
Scenario 4) is currently handled correctly. The ->cblist remains enabled
on CPU down and gets re-initialized on CPU up. The toggling operation
will wait until ->cblist is empty, so ->cblist will remain empty until
CPU-up time.
The scenario 3) would run into trouble though, as the rdp is disabled
on CPU down and not re-initialized/re-enabled on CPU up. Except that
in this case, ->cblist is guaranteed to be empty because all its
callbacks were migrated away at CPU-down time. And the CPU-up code
already initializes and enables any empty ->cblist structures in order
to handle the possibility of early-boot invocations of call_rcu() in
the case where such invocations don't occur. So all that need be done
is to adjust the locking.
Cc: Josh Triplett <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Mathieu Desnoyers <[email protected]>
Cc: Lai Jiangshan <[email protected]>
Cc: Joel Fernandes <[email protected]>
Cc: Neeraj Upadhyay <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Inspired-by: Paul E. McKenney <[email protected]>
Tested-by: Boqun Feng <[email protected]>
Signed-off-by: Frederic Weisbecker <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>
|
|
Offloading and de-offloading RCU callback processes must be done
carefully. There must never be a time at which callback processing is
disabled because the task driving the offloading or de-offloading might be
preempted or otherwise stalled at that point in time, which would result
in OOM due to calbacks piling up indefinitely. This implies that there
will be times during which a given CPU's callbacks might be concurrently
invoked by both that CPU's RCU_SOFTIRQ handler (or, equivalently, that
CPU's rcuc kthread) and by that CPU's rcuo kthread.
This situation could fatally confuse both rcu_barrier() and the
CPU-hotplug offlining process, so these must be excluded during any
concurrent-callback-invocation period. In addition, during times of
concurrent callback invocation, changes to ->cblist must be protected
both as needed for RCU_SOFTIRQ and as needed for the rcuo kthread.
This commit therefore defines and documents the states for a state
machine that coordinates offloading and deoffloading.
Cc: Josh Triplett <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Mathieu Desnoyers <[email protected]>
Cc: Lai Jiangshan <[email protected]>
Cc: Joel Fernandes <[email protected]>
Cc: Neeraj Upadhyay <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Inspired-by: Paul E. McKenney <[email protected]>
Tested-by: Boqun Feng <[email protected]>
Signed-off-by: Frederic Weisbecker <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>
|
|
This commit gathers the rcu_segcblist ->enabled and ->offloaded property
field into a single ->flags bitmask to avoid further proliferation of
individual u8 fields in the structure. This change prepares for the
state formerly known as ->offloaded state to be modified at runtime.
Cc: Josh Triplett <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Mathieu Desnoyers <[email protected]>
Cc: Lai Jiangshan <[email protected]>
Cc: Joel Fernandes <[email protected]>
Cc: Neeraj Upadhyay <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Inspired-by: Paul E. McKenney <[email protected]>
Tested-by: Boqun Feng <[email protected]>
Signed-off-by: Frederic Weisbecker <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>
|
|
This commit adds debug checks near the end of rcu_do_batch() that emit
warnings if an empty rcu_segcblist structure has non-zero segment counts,
or, conversely, if a non-empty structure has all-zero segment counts.
Signed-off-by: Joel Fernandes (Google) <[email protected]>
[ paulmck: Fix queue/segment-length checks. ]
Signed-off-by: Paul E. McKenney <[email protected]>
|
|
This commit adds tracing to track how the segcb list changes before/after
acceleration, during queuing and during dequeuing.
This tracing helped discover an optimization that avoided needless GP
requests when no callbacks were accelerated. The tracing overhead is
minimal as each segment's length is now stored in the respective segment.
Reviewed-by: Frederic Weisbecker <[email protected]>
Reviewed-by: Neeraj Upadhyay <[email protected]>
Signed-off-by: Joel Fernandes (Google) <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>
|
|
The full memory barriers in rcu_segcblist_enqueue() and in rcu_do_batch()
are not needed because rcu_segcblist_add_len(), and thus also
rcu_segcblist_inc_len(), already includes a memory barrier *before*
and *after* the length of the list is updated.
This commit therefore removes these redundant smp_mb() invocations.
Reviewed-by: Frederic Weisbecker <[email protected]>
Signed-off-by: Joel Fernandes (Google) <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>
|
|
Add counting of segment lengths of segmented callback list.
This will be useful for a number of things such as knowing how big the
ready-to-execute segment have gotten. The immediate benefit is ability
to trace how the callbacks in the segmented callback list change.
Also this patch remove hacks related to using donecbs's ->len field as a
temporary variable to save the segmented callback list's length. This cannot be
done anymore and is not needed.
Also fix SRCU:
The negative counting of the unsegmented list cannot be used to adjust
the segmented one. To fix this, sample the unsegmented length in
advance, and use it after CB execution to adjust the segmented list's
length.
Reviewed-by: Frederic Weisbecker <[email protected]>
Signed-off-by: Joel Fernandes (Google) <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>
|
|
One counter-intuitive property of RCU is the fact that full memory
barriers are needed both before and after updates to the full
(non-segmented) length. This patch therefore helps to assist the
reader's intuition by adding appropriate comments.
[ paulmck: Wordsmithing. ]
Signed-off-by: Joel Fernandes (Google) <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>
|
|
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.
Update the documents and mention CONFIG_PREEMPTION. Spell out
CONFIG_PREEMPT_RT (instead PREEMPT_RT) since it is an option now.
Signed-off-by: Sebastian Andrzej Siewior <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>
|
|
The PREEMPT_RT wiki moved from kernel.org to the Linux Foundation wiki.
The kernel.org wiki is read only.
This commit therefore updates the URL of the active PREEMPT_RT wiki.
Signed-off-by: Sebastian Andrzej Siewior <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>
|
|
Currently, if a scenario is repeated as in "--configs '4*TREE01'",
the Kconfig analysis is performed for each occurrance (four times in
this example) and each analysis places the exact same data into the
exact same files. This is not really an issue in this repetition-four
example, but it can needlessly consume tens of seconds of wallclock time
for something like "--config '128*TINY01'".
This commit therefore does Kconfig analysis only once per set of
repeats of a given scenario, courtesy of the "sort -u" command and an
automatically generated awk script.
While in the area, this commit also wordsmiths a comment.
Signed-off-by: Paul E. McKenney <[email protected]>
|
|
Tasks Trace RCU uses irq_work_queue() to safely awaken its grace-period
kthread, so this commit therefore causes the TASKS_TRACE_RCU Kconfig
option select the IRQ_WORK Kconfig option.
Reported-by: kernel test robot <[email protected]>
Acked-by: Randy Dunlap <[email protected]> # build-tested
Signed-off-by: Paul E. McKenney <[email protected]>
|
|
This commit adds self tests for early-boot use of RCU-tasks grace periods.
It tests all three variants (Rude, Tasks, and Tasks Trace) and covers
both synchronous (e.g., synchronize_rcu_tasks()) and asynchronous (e.g.,
call_rcu_tasks()) grace-period APIs.
Self-tests are run only in kernels built with CONFIG_PROVE_RCU=y.
Signed-off-by: Uladzislau Rezki (Sony) <[email protected]>
[ paulmck: Handle CONFIG_PROVE_RCU=n and identify test cases' callbacks. ]
Signed-off-by: Paul E. McKenney <[email protected]>
|
|
This commit adds a lockdep_assert_irqs_disabled() call to the
helper macros that release the rcu_node structure's ->lock, namely
to raw_spin_unlock_rcu_node(), raw_spin_unlock_irq_rcu_node() and
raw_spin_unlock_irqrestore_rcu_node(). The point of this is to help track
down a situation where lockdep appears to be insisting that interrupts
are enabled while holding an rcu_node structure's ->lock.
Link: https://lore.kernel.org/lkml/[email protected]/
Signed-off-by: Paul E. McKenney <[email protected]>
|
|
This commit adds a number of lockdep_assert_irqs_disabled() calls
to rcu_sched_clock_irq() and a number of the functions that it calls.
The point of this is to help track down a situation where lockdep appears
to be insisting that interrupts are enabled within these functions, which
should only ever be invoked from the scheduling-clock interrupt handler.
Link: https://lore.kernel.org/lkml/[email protected]/
Signed-off-by: Paul E. McKenney <[email protected]>
|
|
This commit removes an unnecessary #include.
Signed-off-by: Wang Qing <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>
|
|
The try_invoke_on_locked_down_task() function currently requires
that interrupts be enabled, but it is called with interrupts
disabled from rcu_print_task_stall(), resulting in an "IRQs not
enabled as expected" diagnostic. This commit therefore updates
try_invoke_on_locked_down_task() to use raw_spin_lock_irqsave() instead
of raw_spin_lock_irq(), thus allowing use from either context.
Link: https://lore.kernel.org/lkml/[email protected]/
Link: https://lore.kernel.org/lkml/[email protected]/
Reported-by: [email protected]
Signed-off-by: Peter Zijlstra <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>
|
|
Normally, kvm-recheck.sh is run from kvm.sh, which provides the
TORTURE_TRUST_MAKE environment variable that, if a non-empty string,
indicates that the --trust-make command-line parameter has been passed
to kvm.sh. If there was no --trust-make, kvm-recheck.sh insists
that the Make.out file contain at least one "CC" command. Thus, when
kvm-recheck.sh is run standalone to evaluate a prior --trust-make run,
it will incorrectly insist that a proper kernel build did not happen.
This commit therefore causes kvm-recheck.sh to also search the "log"
file in the top-level results directory for the string "--trust-make".
Signed-off-by: Paul E. McKenney <[email protected]>
|
|
Commit 757055ae8ded ("init/console: Use ttynull as a fallback when
there is no console") results in the string "Warning: Failed to add
ttynull console. No stdin, stdout, and stderr for the init process!"
appearing on the console, which the rcutorture scripting interprets as
a warning, which causes every rcutorture run to be flagged. However,
the rcutorture init process never attempts to do any I/O, and thus does
not care that it has no stdin, stdout, or stderr.
This commit therefore causes the rcutorture scripting to ignore this
message.
Signed-off-by: Paul E. McKenney <[email protected]>
|
|
This commit simplifies exit-code plumbing. It makes kvm-recheck.sh return
the value 1 for a build error and 2 for a runtime error. It also makes
kvm-find-errors.sh avoid checking runtime files for --build-only runs.
Signed-off-by: Paul E. McKenney <[email protected]>
|
|
This commit changes the "STOP" file that is used to cleanly halt a running
rcutorture run to "STOP.1" because no scenario directory will ever end
with ".1". If there really was a scenario named "STOP", its directories
would instead be named "STOP", "STOP.2", "STOP.3", and so on. While in
the area, the commit also changes the kernel-run-time checks for this
file to look directly in the directory above $resdir, thus avoiding the
need to pass the TORTURE_STOPFILE environment variable to remote systems.
While in the area, move the STOP.1 file to the top-level directory
covering all of the scenarios.
Signed-off-by: Paul E. McKenney <[email protected]>
|
|
When all of the remote systems have the same number of CPUs, one
approach is to use one "--buildonly" run and one "--dryrun sched" run,
and then distributing the batches out one per remote system. However,
the output of "--dryrun sched" is not made for parsing, so this commit
adds a "--dryrun batches" that provides the same information in easily
parsed form.
Signed-off-by: Paul E. McKenney <[email protected]>
|
|
By default, the "panic" kernel parameter is zero, which causes the kernel
to loop indefinitely after a panic(). The rcutorture scripting will
eventually kill the corresponding qemu process, but only after waiting
for the full run duration plus a few minutes. This works, but delays
notifying the developer of the failure.
This commit therefore causes the rcutorture scripting to pass the
"panic=-1" kernel parameter, which caused the kernel to instead
unceremoniously shut down immediately. This in turn causes qemu to
terminate, so that if all of the runs in a given batch panic(), the
rcutorture scripting can immediately proceed to the next batch.
Signed-off-by: Paul E. McKenney <[email protected]>
|
|
This commit adds the test summary to the end of the log in the top-level
directory containing the kvm.sh test artifacts. While in the area, it adds
the kvm.sh exit code to this test summary.
Signed-off-by: Paul E. McKenney <[email protected]>
|
|
Currently, passing something like "--kconfig CONFIG_NR_CPUS=2" to kvm.sh
has no effect on scenario scheduling. For scenarios that do not specify
the number of CPUs, this can result in kvm.sh wastefully scheduling only
one scenario at a time even when the --kconfig argument would allow
a number to be run concurrently. This commit therefore makes kvm.sh
consider the --kconfig arguments when scheduling scenarios across the
available CPUs.
Signed-off-by: Paul E. McKenney <[email protected]>
|
|
The kvm.sh script uses kvm-find-errors.sh to evaluate whether or not
a build failed. Unfortunately, kvm-find-errors.sh returns success if
there are no failed runs (including when there are no runs at all) even if
there are build failures. This commit therefore makes kvm-find-errors.sh
return failure in response to build failures.
Signed-off-by: Paul E. McKenney <[email protected]>
|
|
Yes, you can mentally subtract the timestamps, but this commit makes
the computer do this work.
Signed-off-by: Paul E. McKenney <[email protected]>
|
|
Given that kvm.sh in invoked from scripts, it is only natural for
different levels of scripting to provide their own Kconfig option values,
for example. Unfortunately, right now, the last such argument on the
command line wins.
This commit therefore makes the --bootargs, --configs, --kconfigs,
--kmake-args, and --qemu-args argument values accumulate. For example,
where "--configs TREE01 --configs TREE02" would previously have run only
scenario TREE02, now it will run both scenarios.
Signed-off-by: Paul E. McKenney <[email protected]>
|
|
Currently, the "date" command producing the output on the kvm.sh "Test
Summary" line is executed at the beginning of the test, which produces a
date that is less than helpful to someone wanting to know the duration
of the test. This commit therefore defers this command's execution to
the end of the test.
Signed-off-by: Paul E. McKenney <[email protected]>
|
|
The rcutorture scripts' identify_qemu_vcpus() function expects `lscpu`
to have a "CPU: " line, for example:
CPU(s): 8
But different local language settings can give different results:
Processeur(s) : 8
As a result, identify_qemu_vcpus() may return an empty string, resulting
in the following warning (with the same local language settings):
kvm-test-1-run.sh: ligne 138 : test: : nombre entier attendu comme expression
This commit therefore changes identify_qemu_vcpus() to use getconf,
which produces local-language-independend output.
Cc: Josh Triplett <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Mathieu Desnoyers <[email protected]>
Cc: Lai Jiangshan <[email protected]>
Cc: [email protected]
Signed-off-by: Frederic Weisbecker <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>
|
|
This commit adds a config2csv.sh script that converts the specified
torture-test scenarios' Kconfig options and kernel-boot parameters to
.csv format. This allows easier comparison of scenarios when one fails
and another does not.
Signed-off-by: Paul E. McKenney <[email protected]>
|
|
Distributed execution of rcutorture is eased if the qemu execution can
be split from the building of the kernel, as this allows target systems
to be used that are not set up to build kernels. It also avoids issues
with toolchain version skew across the cluster, aside of course from
qemu and KVM version skew.
This commit therefore records needed data as comments in the qemu-cmd file
and moves recording of the starting time to just before qemu is launched.
Signed-off-by: Paul E. McKenney <[email protected]>
|
|
Scripts like kvm-check-branches.sh group runs under a single directory
in resdir in order to allow easier retrospective analysis. However, they
do this by letting kvm.sh create a directory as usual and then moving it
after the run. This can be very confusing when looking at the results
while kvm-check-branches.sh is running. This commit therefore enables
--datestamp to hand subdirectories to kvm.sh.
Signed-off-by: Paul E. McKenney <[email protected]>
|
|
Knowing the number of builds that kvm.sh will split a run into allows
estimation of the duration of a test, give or take build duration.
This commit therefore adds a line of output to "--dryrun sched" that
gives the number of builds that will be run. This excludes "builds"
for repeated scenarios that reuse an earlier build.
Signed-off-by: Paul E. McKenney <[email protected]>
|
|
Knowing the number of batches that kvm.sh will split a run into allows
estimation of the duration of a test, give or take the number of builds.
This commit therefore adds a line of output to "--dryrun sched" that
gives the number of batches that will be run.
Signed-off-by: Paul E. McKenney <[email protected]>
|
|
The --kcsan argument to kvm.sh adds CONFIG_KCSAN_VERBOSE=y in order to
get more detail from the KCSAN reports. However, this Kconfig option
requires lockdep to be enabled. This commit therefore causes --kcsan
to also enable lockdep.
Signed-off-by: Paul E. McKenney <[email protected]>
|
|
Currently, RCU CPU stall warning messages will NMI whatever CPU looks
like it is blocking either the current grace period or the grace-period
kthread. This can produce confusing output if the target CPU is offline.
This commit therefore checks for offline CPUs.
Signed-off-by: Paul E. McKenney <[email protected]>
|
|
When the RCU CPU stall-warning code detects that the RCU grace-period
kthread is being starved, it dumps that kthread's stack. This can
sometimes be useful, but it is also useful to know what is running on the
CPU that this kthread is attempting to run on. This commit therefore
adds a stack trace of this CPU in order to help track down whatever it
is that might be preventing RCU's grace-period kthread from running.
Signed-off-by: Paul E. McKenney <[email protected]>
|
|
There is a rather obtuse string that can be printed as part of an
expedited RCU CPU stall-warning message that starts with "blocking
rcu_node structures". Under normal conditions, most of this message
is just repeating the list of CPUs blocking the current expedited grace
period, but in a manner that is rather difficult to read. This commit
therefore marks this message as "(internal RCU debug)" in an effort to
give people the option of avoiding wasting time attempting to extract
nonexistent additional meaning from this portion of the message.
Reported-by: Jonathan Lemon <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>
|
|
This commit adds the desired CPU, the actual CPU, and nr_cpu_ids to
the wrong-CPU warning in scftorture_invoker(), the better to help with
debugging.
Signed-off-by: Paul E. McKenney <[email protected]>
|
|
RCU guarantees that anything seen by a given reader will also be seen
after any grace period that must wait on that reader. This is very likely
to hold based on inspection, but the advantage of having rcutorture do
the inspecting is that rcutorture doesn't mind inspecting frequently
and often.
This commit therefore adds code to test RCU's global memory ordering.
Signed-off-by: Paul E. McKenney <[email protected]>
|
|
This commit adds reader-side testing of the polling grace-period API.
This testing verifies that a cookie obtained in an SRCU read-side critical
section does not get a true return from poll_state_synchronize_srcu()
within that same critical section.
Link: https://lore.kernel.org/rcu/[email protected]/
Reported-by: Kent Overstreet <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>
|
|
This commit adds writer-side testing of the polling grace-period API.
One test verifies that the polling API sees a grace period caused by
some other mechanism. Another test verifies that using the polling API
to wait for a grace period does not result in too-short grace periods.
A third test verifies that the polling API does not report
completion within a read-side critical section. A fourth and final
test verifies that the polling API does report completion given an
intervening grace period.
Link: https://lore.kernel.org/rcu/[email protected]/
Reported-by: Kent Overstreet <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>
|