Some RCU bugs have been sensitive to the frequency of CPU-hotplug
operations, which have been gradually increased over time. But this
frequency is now at the one-second lower limit that can be specified using
the rcutorture.onoff_interval kernel parameter. This commit therefore
changes the units of rcutorture.onoff_interval from seconds to jiffies,
and also sets the value specified for this kernel parameter in the TREE03
rcutorture scenario to 200, which is 200 milliseconds for HZ=1000.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The main race with the early part of grace-period initialization appears
to be with CPU hotplug. To more fully open this race window, this commit
moves the rcu_gp_slow() from the beginning of the early initialization
loop to follow that loop, thus widening the race window, especially for
the rcu_node structures that are initialized last. This commit also
expands rcutree.gp_preinit_delay from 3 to 12, giving the same overall
delay in the grace period, but concentrated in the spot where it will
do the most good.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Although warnings about close calls are printed by kvm-recheck.sh,
kvm-find-errors.sh currently ignores them. This could easily result
in someone failing to investigate close calls, so this commit makes
them visible to kvm-find-errors.sh.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The TREE08-T.boot file was used to provide alternative options for
debugging, but things have changed, it has not kept up, and it has not
been used or missed. This commit therefore removes it.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The torture scripting currently builds each kernel from a set of parallel
runs in its own build directory. This can waste quite a bit of space when
running large numbers of concurrent scenarios, and pointlessly given that
the builds are run sequentially (albeit with a largish -j number passed to
"make"). This commit therefore places all build-command output in the
results directory, then does all builds in a single "b1" build directory.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Currently, kvm-find-errors.sh looks only for build errors ("error:"),
so this commit makes it also locate build warnings ("warning:").
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Nicholas Piggin <npiggin@gmail.com>
With the addition of the end-of-test state, it is not uncommon for the
kvm.sh summary lines to overflow 80 characters. This commit therefore
applies abbreviations in order to make the line fit into 80 characters
with high probability.
And yes, I did make heavy use of punched cards back in the day, so 80
columns it is for my xterms! ;-)
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Nicholas Piggin <npiggin@gmail.com>
This commit adds the end-of-test test, if present in the console output,
to the kvm.sh test summary that is printed by kvm-recheck.sh. Note that
this only applies to rcutorture console output.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Nicholas Piggin <npiggin@gmail.com>
The rcutorture scripting scans the console output twice, once to look
for various sorts of hangs and again to find warnings and panics.
Unfortunately, only the output of the second scan gets written to the
console.log.diags file, which can cause hangs to be overlooked.
This commit therefore folds the parse-torture.sh script (which looks
for hangs) into the parse-console.sh script (which looks for warnings
and panics). This allows both types of failure information to be
added to console.log.diags, while still reliably removing this file
when it proves to be empty.
This also fixes a long-standing bug where rcuperf log files would
unconditionally complain about a hang.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Nicholas Piggin <npiggin@gmail.com>
This commit adds a script that allows viewing the build and/or
console output from failed rcutorture, locktorture, or rcuperf runs.
This replaces a time-honored but inefficient manual procedure that uses
cut and paste.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Nicholas Piggin <npiggin@gmail.com>
The default values for nreader and nwriter are apparently not all that
user-friendly, resulting in people doing scalability tests that ran all
runs at large scale. This commit therefore makes both the nreaders and
nwriters module default to the number of CPUs, and adds a comment to
rcuperf.c stating that the number of CPUs should be specified using the
nr_cpus kernel boot parameter. This commit also eliminates the redundant
rcuperf scripting specification of default values for these parameters.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The rcuperf trace-event processing counted every "done" trace event
as a piggyback, which is incorrect because the task that started the
grace period didn't piggyback at all. This commit fixes this problem
by recording the task that started a given grace period and ignoring
that task's "done" record for that grace period.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The rcuperf event-trace processing assumes that expedited grace periods
start and end on the same task, an assumption that was violated by moving
expedited grace-period processing to workqueues. This commit removes
this now-fallacious assumption from rcuperf's event-trace processing.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The purpose of jitter is to expose concurrency bugs due to invalid
assumptions about forward progress. There is usually little point
in jitter when measuring performance. This commit therefore defaults
jitter off when running rcuperf. You can override this by specifying
the kvm.sh "--jitter" argument -after- the "--torture rcuperf"
argument. No idea why you would want this, but if you do, that is
how you do it.
One example of a conccurrency bug that this jitter might expose is one
in which the developer assumed that a given short region of code would be
guaranteed to execute within some short time limit. Such assumptions are
invalid in virtualized environments because the hupervisor can preempt
the guest OS at any point, even when the guest OS thinks that it has
disabled interrupts.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The 512 megabyte memory size has served quite well, but more memory
is required when using large trace buffers on large systems. This
commit therefore adds a --memory argument to the kvm.sh script, which
allows the memory size to be specified on the command line, for example,
"--memory 768", --memory 800M", or "--memory 2G".
Reported-by: Sebastian Siewior <bigeasy@linutronix.de>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This commit adds support of the qemu command qemu-system-aarch64
to rcutorture.
Signed-off-by: Lihao Liang <lianglihao@huawei.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The kvm.sh header comment is a bit of a relic, so this commit brings
it up to date.
Reported-by: Lihao Liang <lianglihao@huawei.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Commit 6f1982fedd ("sched/isolation: Handle the nohz_full= parameter")
broke CONFIG_NO_HZ_FULL_ALL=y kernels. This breakage is due to the code
under CONFIG_NO_HZ_FULL_ALL failing to invoke the shiny new housekeeping
functions. This means that rcutorture scenario TREE04 now emits RCU CPU
stall warnings due to the RCU grace-period kthreads not being awakened
at a time of their choosing, or perhaps even not at all:
[ 27.731422] rcu_bh kthread starved for 21001 jiffies! g18446744073709551369 c18446744073709551368 f0x0 RCU_GP_WAIT_FQS(3) ->state=0x402 ->cpu=3
[ 27.731423] rcu_bh I14936 9 2 0x80080000
[ 27.731435] Call Trace:
[ 27.731440] __schedule+0x31a/0x6d0
[ 27.731442] schedule+0x31/0x80
[ 27.731446] schedule_timeout+0x15a/0x320
[ 27.731453] ? call_timer_fn+0x130/0x130
[ 27.731457] rcu_gp_kthread+0x66c/0xea0
[ 27.731458] ? rcu_gp_kthread+0x66c/0xea0
Because no one has complained about CONFIG_NO_HZ_FULL_ALL=y being broken,
I hypothesize that no one is in fact using it, other than rcutorture.
This commit therefore eliminates CONFIG_NO_HZ_FULL_ALL and updates
rcutorture's config files to instead use the nohz_full= kernel parameter
to put the desired CPUs into nohz_full mode.
Fixes: 6f1982fedd ("sched/isolation: Handle the nohz_full= parameter")
Reported-by: kernel test robot <xiaolong.ye@intel.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <frederic@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luiz Capitulino <lcapitulino@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Wanpeng Li <kernellwp@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Jonathan Corbet <corbet@lwn.net>
The purpose of torture_runnable is to allow rcutorture and locktorture
to be started and stopped via sysfs when they are built into the kernel
(as in not compiled as loadable modules). However, the 0444 permissions
for both instances of torture_runnable prevent this use case from ever
being put into practice. Given that there have been no complaints
about this deficiency, it is reasonable to conclude that no one actually
makes use of this sysfs capability. The perf_runnable module parameter
for rcuperf is in the same situation.
This commit therefore removes both torture_runnable instances as well
as perf_runnable.
Reported-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Check for build-directory existence and write permissions are provided in
both 'kvm-test-1-run.sh' an 'kvm-build.sh'. Because the 'kvm-build.sh'
is dependent on 'kvm-test-1-run.sh' ('kvm-build.sh' uses variables that
defined from its caller.), these checks are unnecessarily duplicated.
This commit therefore removes the check in from the 'kvm-build.sh' script.
Signed-off-by: SeongJae Park <sj38.park@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Inclusions of 'functions.sh' from 'kvm-test-1-run.sh' and
'kvm-recheck*.sh' use its absolute path. Because the directory containing
'functions.sh' is already in PATH, the full path is unnecessary. This
commit therefore simplifies the inclusions to use the short relative path.
Signed-off-by: SeongJae Park <sj38.park@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Both the 'kvm.sh' and 'kvm-test-1-run.sh' scripts log messages by printing
the message to 'stdout' and then also printing it into the log file.
Generation of the message thus occurs twice, once for 'stdout' and once
for the log file. Moreover, many of the messages contain 'date' output,
which results in date being invoked twice (once for stdout print, once
for log file write). As a result, the date information in stdout and
log file can differ, which could cause confusion.
This commit therefore simplifies the logging procedure by using 'tee'.
Signed-off-by: SeongJae Park <sj38.park@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The kvm-recheck-(lock|rcu|rcuperf).sh scripts check whether the
user-specified results directory exists. If not, it prints out error
message that says the specified directory is unreadable. To make the
message more precise, this commit adds a readability check.
Fixes: 2193e1604e ("rcutorture: Abstract kvm-recheck.sh")
Signed-off-by: SeongJae Park <sj38.park@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The 'kvm.sh' rcutorture script requires that it be invoked from the top
of Linux-kernel source tree. It is just a subtle restriction, but users
using it for the first time could forget the restriction and be confused.
Moreover, it makes commands a little longer, which can be frustrating.
This commit therefore lets users invoke the script from any location.
Signed-off-by: SeongJae Park <sj38.park@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The '--qemu-args' option's help text is wrongly copied from '--qemu-cmd'
option and its argument type description message format is inconsistent
with other arguments. This commit fixes the usage and type messages to
be consistent with others.
Fixes: e9ce640001 ("rcutorture: Add --qemu-args argument to kvm.sh")
Signed-off-by: SeongJae Park <sj38.park@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The variable `alldone` is defined but not used within an awk script.
This commit therefore removes it.
Fixes:53954671033d ("rcutorture: Do better bin packing")
Signed-off-by: SeongJae Park <sj38.park@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The 'config2frag.sh' script is not used, so this commit removes it.
Fixes: c87b9c601a ("rcutorture: Add KVM-based test framework")
Signed-off-by: SeongJae Park <sj38.park@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The 'configinit.sh' script checks the format of optional argument for the
build directory, printing an error message if the format is not valid.
However, the error message uses the wrong variable, indicating an empty
string even though the user entered a non-empty (but erroneous) string.
This commit fixes the script to use the correct variable.
Fixes: c87b9c601a ("rcutorture: Add KVM-based test framework")
Signed-off-by: SeongJae Park <sj38.park@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Because %p prints "(null)" and %pK prints "0000000000000000" or (on
32-bit systems) "00000000", this commit adjusts torture-test scripting
accordingly.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Pull core locking updates from Ingo Molnar:
"The main changes in this cycle are:
- Another attempt at enabling cross-release lockdep dependency
tracking (automatically part of CONFIG_PROVE_LOCKING=y), this time
with better performance and fewer false positives. (Byungchul Park)
- Introduce lockdep_assert_irqs_enabled()/disabled() and convert
open-coded equivalents to lockdep variants. (Frederic Weisbecker)
- Add down_read_killable() and use it in the VFS's iterate_dir()
method. (Kirill Tkhai)
- Convert remaining uses of ACCESS_ONCE() to
READ_ONCE()/WRITE_ONCE(). Most of the conversion was Coccinelle
driven. (Mark Rutland, Paul E. McKenney)
- Get rid of lockless_dereference(), by strengthening Alpha atomics,
strengthening READ_ONCE() with smp_read_barrier_depends() and thus
being able to convert users of lockless_dereference() to
READ_ONCE(). (Will Deacon)
- Various micro-optimizations:
- better PV qspinlocks (Waiman Long),
- better x86 barriers (Michael S. Tsirkin)
- better x86 refcounts (Kees Cook)
- ... plus other fixes and enhancements. (Borislav Petkov, Juergen
Gross, Miguel Bernal Marin)"
* 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (70 commits)
locking/x86: Use LOCK ADD for smp_mb() instead of MFENCE
rcu: Use lockdep to assert IRQs are disabled/enabled
netpoll: Use lockdep to assert IRQs are disabled/enabled
timers/posix-cpu-timers: Use lockdep to assert IRQs are disabled/enabled
sched/clock, sched/cputime: Use lockdep to assert IRQs are disabled/enabled
irq_work: Use lockdep to assert IRQs are disabled/enabled
irq/timings: Use lockdep to assert IRQs are disabled/enabled
perf/core: Use lockdep to assert IRQs are disabled/enabled
x86: Use lockdep to assert IRQs are disabled/enabled
smp/core: Use lockdep to assert IRQs are disabled/enabled
timers/hrtimer: Use lockdep to assert IRQs are disabled/enabled
timers/nohz: Use lockdep to assert IRQs are disabled/enabled
workqueue: Use lockdep to assert IRQs are disabled/enabled
irq/softirqs: Use lockdep to assert IRQs are disabled/enabled
locking/lockdep: Add IRQs disabled/enabled assertion APIs: lockdep_assert_irqs_enabled()/disabled()
locking/pvqspinlock: Implement hybrid PV queued/unfair locks
locking/rwlocks: Fix comments
x86/paravirt: Set up the virt_spin_lock_key after static keys get initialized
block, locking/lockdep: Assign a lock_class per gendisk used for wait_for_completion()
workqueue: Remove now redundant lock acquisitions wrt. workqueue flushes
...
Pull RCU updates from Ingo Molnar:
"The main changes in this cycle are:
- Documentation updates
- RCU CPU stall-warning updates
- Torture-test updates
- Miscellaneous fixes
Size wise the biggest updates are to documentation. Excluding
documentation most of the code increase comes from a single commit
which expands debugging"
* 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (24 commits)
srcu: Add parameters to SRCU docbook comments
doc: Rewrite confusing statement about memory barriers
memory-barriers.txt: Fix typo in pairing example
rcu/segcblist: Include rcupdate.h
rcu: Add extended-quiescent-state testing advice
rcu: Suppress lockdep false-positive ->boost_mtx complaints
rcu: Do not include rtmutex_common.h unconditionally
torture: Provide TMPDIR environment variable to specify tmpdir
rcutorture: Dump writer stack if stalled
rcutorture: Add interrupt-disable capability to stall-warning tests
rcu: Suppress RCU CPU stall warnings while dumping trace
rcu: Turn off tracing before dumping trace
rcu: Make RCU CPU stall warnings check for irq-disabled CPUs
sched,rcu: Make cond_resched() provide RCU quiescent state
sched: Make resched_cpu() unconditional
irq_work: Map irq_work_on_queue() to irq_work_on() in !SMP
rcu: Create call_rcu_tasks() kthread at boot time
rcu: Fix up pending cbs check in rcu_prepare_for_idle
memory-barriers: Rework multicopy-atomicity section
memory-barriers: Replace uses of "transitive"
...
Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.
By default all files without license information are under the default
license of the kernel, which is GPL version 2.
Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.
This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.
How this work was done:
Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,
Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.
The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.
The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.
Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if <5
lines).
All documentation files were explicitly excluded.
The following heuristics were used to determine which SPDX license
identifiers to apply.
- when both scanners couldn't find any license traces, file was
considered to have no license information in it, and the top level
COPYING file license applied.
For non */uapi/* files that summary was:
SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 11139
and resulted in the first patch in this series.
If that file was a */uapi/* path one, it was "GPL-2.0 WITH
Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was:
SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 WITH Linux-syscall-note 930
and resulted in the second patch in this series.
- if a file had some form of licensing information in it, and was one
of the */uapi/* ones, it was denoted with the Linux-syscall-note if
any GPL family license was found in the file or had no licensing in
it (per prior point). Results summary:
SPDX license identifier # files
---------------------------------------------------|------
GPL-2.0 WITH Linux-syscall-note 270
GPL-2.0+ WITH Linux-syscall-note 169
((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21
((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17
LGPL-2.1+ WITH Linux-syscall-note 15
GPL-1.0+ WITH Linux-syscall-note 14
((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5
LGPL-2.0+ WITH Linux-syscall-note 4
LGPL-2.1 WITH Linux-syscall-note 3
((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3
((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1
and that resulted in the third patch in this series.
- when the two scanners agreed on the detected license(s), that became
the concluded license(s).
- when there was disagreement between the two scanners (one detected a
license but the other didn't, or they both detected different
licenses) a manual inspection of the file occurred.
- In most cases a manual inspection of the information in the file
resulted in a clear resolution of the license that should apply (and
which scanner probably needed to revisit its heuristics).
- When it was not immediately clear, the license identifier was
confirmed with lawyers working with the Linux Foundation.
- If there was any question as to the appropriate license identifier,
the file was flagged for further research and to be revisited later
in time.
In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.
Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights. The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.
Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.
In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.
Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
- a full scancode scan run, collecting the matched texts, detected
license ids and scores
- reviewing anything where there was a license detected (about 500+
files) to ensure that the applied SPDX license was correct
- reviewing anything where there was no detection but the patch license
was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
SPDX license was correct
This produced a worksheet with 20 files needing minor correction. This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.
These .csv files were then reviewed by Greg. Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected. This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.) Finally Greg ran the script using the .csv files to
generate the patches.
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
For several reasons, it is desirable to use {READ,WRITE}_ONCE() in
preference to ACCESS_ONCE(), and new code is expected to use one of the
former. So far, there's been no reason to change most existing uses of
ACCESS_ONCE(), as these aren't currently harmful.
However, for some features it is necessary to instrument reads and
writes separately, which is not possible with ACCESS_ONCE(). This
distinction is critical to correct operation.
The bulk of the kernel code can be transformed via Coccinelle to use
{READ,WRITE}_ONCE(), though this only modifies users of ACCESS_ONCE(),
and not the implementation itself. As such, it has the potential to
break homebrew ACCESS_ONCE() macros seen in some user code in the kernel
tree (e.g. the virtio code, as fixed in commit ea9156fb3b).
To avoid fragility if/when that transformation occurs, this patch
reworks the definitions of {READ,WRITE}_ONCE() in the rcutorture formal
tests, and removes the unused ACCESS_ONCE() helper. There should be no
functional change as a result of this patch.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: davem@davemloft.net
Cc: linux-arch@vger.kernel.org
Cc: mpe@ellerman.id.au
Cc: shuah@kernel.org
Cc: snitzer@redhat.com
Cc: thor.thayer@linux.intel.com
Cc: tj@kernel.org
Cc: viro@zeniv.linux.org.uk
Cc: will.deacon@arm.com
Link: http://lkml.kernel.org/r/1508792849-3115-13-git-send-email-paulmck@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Both rcutorture and locktorture currently place temporary files in /tmp,
in keeping with decades-long tradition. However, sometimes it is useful
to specify an alternative temporary directory, for example, for space
or performance reasons. This commit therefore causes the torture-test
scripting to use the path specified in the TMPDIR environment variable,
or to fall back to traditional /tmp if this variable is not set.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The actual use of TASKS_RCU is only when PREEMPT, otherwise RCU-sched
is used instead. This commit therefore makes synchronize_rcu_tasks()
and call_rcu_tasks() available always, but mapped to synchronize_sched()
and call_rcu_sched(), respectively, when !PREEMPT. This approach also
allows some #ifdefs to be removed from rcutorture.
Reported-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Ingo Molnar <mingo@kernel.org>
The maxcpus= kernel boot parameter limits the number of CPUs brought
online at boot time, but it does nothing to prevent additional CPUs
from being brought up later. Placing a hard cap on the total number
of CPUs is instead the job of the nr_cpus= boot parameter. This commit
therefore switches the configfrag_boot_cpus() shell function from maxcpus=
to nr_cpus=. This commit also adds a nr_cpus=43 kernel parameter to RCU's
TREE01 test scenario, but retains the maxcpus=8 kernel parameter in order
to test the ability of RCU expedited grace periods to handle new CPUs
coming online for the first time during grace-period initialization.
Finally, this commit makes the torture scheduling allow maxcpus= to
override other means of specifying the number of CPUs to allow for.
This last works because the torture kernel modules size their workloads
based on the number of CPUs present at the start of the test, not the
ultimate number of CPUs.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Strings used in event tracing need to be specially handled, for example,
being copied to the trace buffer instead of being pointed to by the trace
buffer. Although the TPS() macro can be used to "launder" pointed-to
strings, this might not be all that effective within a loadable module.
This commit therefore copies rcutorture's strings to the trace buffer.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Currently, rcutorture groups runs in batches, building each scenario in
a given batch, then invoking qemu to run all the kernels in the batch.
Of course, if a given scenario's kernel fails to build, there is no qemu
run for that scenario. And if all of the kernels in a given batch fail
to build, there are no runs, and rcutorture immediately starts on the
next batch.
But not if --jitter has been specified, which it is by default. In this
case, the jitter scripts are started unconditionally, and rcutorture
waits for them to complete, even though there are no kernels to run.
This commit therefore checks for this situation, and refuses to start
jitter unless at least one of the kernels in the batch built successfully.
This saves substantial time when all scenarios' kernels fail to build,
particularly if a long --duration was specified.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Currently, testing a variant of an existing scenario requires editing
that scenario's file or creating a new scenario file. This is messy
and error prone with respect to changes to scenarios.
This commit therefore adds a --kconfig argument to kvm.sh, so that
'--kconfig "CONFIG_RCU_TRACE=y CONFIG_RCU_EQS_DEBUG=n" will override those
two Kconfig options. In addition, there is now clear precedence:
the config fragment overrides CFcommon, and the --kconfig argument
overrides both.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This commit selects CONFIG_PROVE_LOCKING for the SRCU-u scenario
to get better test coverage.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Classic SRCU is no more, so this commit removes the corresponding
rcutorture boot-parameters file.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tiny RCU's job is to be tiny, so this commit removes its RCU CPU
stall warning code. After this, there is no longer any need for
rcu_sched_ctrlblk and rcu_bh_ctrlblk to be in tiny_plugin.h, so this
commit also moves them to tiny.c.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The CONFIG_RCU_NOCB_CPU_ALL, CONFIG_RCU_NOCB_CPU_NONE, and
CONFIG_RCU_NOCB_CPU_ZERO Kconfig options are used only in testing and
are redundant with the rcu_nocbs= boot parameter. This commit therefore
removes these three Kconfig options and adjusts the rcutorture scripts
to use the boot parameter instead.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
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>
Classic SRCU was only ever intended to be a fallback in case of issues
with Tree/Tiny SRCU, and the latter two are doing quite well in testing.
This commit therefore removes Classic SRCU.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The sparse-based checking for non-RCU accesses to RCU-protected pointers
has been around for a very long time, and it is now the only type of
sparse-based checking that is optional. This commit therefore makes
it unconditional.
Reported-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Fengguang Wu <fengguang.wu@intel.com>
Paul E. McKenney