From: "Paul E. McKenney"
Although smp_call_function() has the advantage of simplicity, using
it to check for cross-CPU clock desynchronization means that any CPU
being slow reduces the sensitivity of the checking across all CPUs.
And it is not uncommon for smp_call_function() latencies to be in
determine whether to add or
to subtract.
Cc: John Stultz
Cc: Thomas Gleixner
Cc: Stephen Boyd
Cc: Jonathan Corbet
Cc: Mark Rutland
Cc: Marc Zyngier
Cc: Andi Kleen
Reported-by: Chris Mason
[ paulmck: Apply Randy Dunlap feedback. ]
Signed-off-by: Paul E. McKenney
---
Documentation/admin-gu
et
Cc: Mark Rutland
Cc: Marc Zyngier
Cc: Andi Kleen
Reported-by: Chris Mason
[ paulmck: Add "static" to clocksource_verify_one_cpu() per kernel test robot
feedback. ]
Signed-off-by: Paul E. McKenney
---
arch/x86/kernel/kvmclock.c | 2 +-
arch/x86/kernel/tsc.c | 3 +-
in
le marking will be apparent.
Cc: John Stultz
Cc: Thomas Gleixner
Cc: Stephen Boyd
Cc: Jonathan Corbet
Cc: Mark Rutland
Cc: Marc Zyngier
Cc: Andi Kleen
Reported-by: Chris Mason
[ paulmck: Per-clocksource retries per Neeraj Upadhyay feedback. ]
[ paulmck: Don't reset injectfail per Neera
_delay_run is the value one, that is single-call runs.
This facility is intended for diagnostic use only, and should be avoided
on production systems.
Cc: John Stultz
Cc: Thomas Gleixner
Cc: Stephen Boyd
Cc: Jonathan Corbet
Cc: Mark Rutland
Cc: Marc Zyngier
Cc: Andi Kleen
[ paulmck: Apply Ri
From: "Paul E. McKenney"
Although smp_call_function() has the advantage of simplicity, using
it to check for cross-CPU clock desynchronization means that any CPU
being slow reduces the sensitivity of the checking across all CPUs.
And it is not uncommon for smp_call_function() latencies to be in
determine whether to add or
to subtract.
Cc: John Stultz
Cc: Thomas Gleixner
Cc: Stephen Boyd
Cc: Jonathan Corbet
Cc: Mark Rutland
Cc: Marc Zyngier
Cc: Andi Kleen
Reported-by: Chris Mason
[ paulmck: Apply Randy Dunlap feedback. ]
Signed-off-by: Paul E. McKenney
---
Documentation/admin-gu
et
Cc: Mark Rutland
Cc: Marc Zyngier
Cc: Andi Kleen
Reported-by: Chris Mason
[ paulmck: Add "static" to clocksource_verify_one_cpu() per kernel test robot
feedback. ]
Signed-off-by: Paul E. McKenney
---
arch/x86/kernel/kvmclock.c | 2 +-
arch/x86/kernel/tsc.c | 3 +-
in
_delay_run is the value one, that is single-call runs.
This facility is intended for diagnostic use only, and should be avoided
on production systems.
Cc: John Stultz
Cc: Thomas Gleixner
Cc: Stephen Boyd
Cc: Jonathan Corbet
Cc: Mark Rutland
Cc: Marc Zyngier
Cc: Andi Kleen
[ paulmck: Apply Ri
le marking will be apparent.
Cc: John Stultz
Cc: Thomas Gleixner
Cc: Stephen Boyd
Cc: Jonathan Corbet
Cc: Mark Rutland
Cc: Marc Zyngier
Cc: Andi Kleen
Reported-by: Chris Mason
[ paulmck: Per-clocksource retries per Neeraj Upadhyay feedback. ]
[ paulmck: Don't reset injectfail per Neera
From: "Paul E. McKenney"
Although smp_call_function() has the advantage of simplicity, using
it to check for cross-CPU clock desynchronization means that any CPU
being slow reduces the sensitivity of the checking across all CPUs.
And it is not uncommon for smp_call_function() latencies to be in
_delay_run is the value one, that is single-call runs.
This facility is intended for diagnostic use only, and should be avoided
on production systems.
Cc: John Stultz
Cc: Thomas Gleixner
Cc: Stephen Boyd
Cc: Jonathan Corbet
Cc: Mark Rutland
Cc: Marc Zyngier
Cc: Andi Kleen
[ paulmck: Apply Ri
determine whether to add or
to subtract.
Cc: John Stultz
Cc: Thomas Gleixner
Cc: Stephen Boyd
Cc: Jonathan Corbet
Cc: Mark Rutland
Cc: Marc Zyngier
Cc: Andi Kleen
Reported-by: Chris Mason
[ paulmck: Apply Randy Dunlap feedback. ]
Signed-off-by: Paul E. McKenney
---
Documentation/admin-gu
le marking will be apparent.
Cc: John Stultz
Cc: Thomas Gleixner
Cc: Stephen Boyd
Cc: Jonathan Corbet
Cc: Mark Rutland
Cc: Marc Zyngier
Cc: Andi Kleen
Reported-by: Chris Mason
[ paulmck: Per-clocksource retries per Neeraj Upadhyay feedback. ]
[ paulmck: Don't reset injectfail per Neera
et
Cc: Mark Rutland
Cc: Marc Zyngier
Cc: Andi Kleen
Reported-by: Chris Mason
[ paulmck: Add "static" to clocksource_verify_one_cpu() per kernel test robot
feedback. ]
Signed-off-by: Paul E. McKenney
---
arch/x86/kernel/kvmclock.c | 2 +-
arch/x86/kernel/tsc.c | 3 +-
in
From: "Paul E. McKenney"
This commit adapts the "Concurrency bugs should fear the big bad data-race
detector (part 2)" LWN article (https://lwn.net/Articles/816854/)
to kernel-documentation form. This allows more easily updating the
material as needed.
Suggested-by: Thomas
From: Akira Yokosawa
atomic_ops.rst was removed by commit f0400a77ebdc ("atomic: Delete
obsolete documentation").
Remove the broken link in tools/memory-model/Documentation/simple.txt.
Cc: Peter Zijlstra
Signed-off-by: Akira Yokosawa
Signed-off-by: Paul E. McKenney
---
From: Mauro Carvalho Chehab
Changeset b00aedf978aa ("doc: Convert to rcu_dereference.txt to
rcu_dereference.rst")
renamed: Documentation/RCU/rcu_dereference.txt
to: Documentation/RCU/rcu_dereference.rst.
Update its cross-reference accordingly.
Signed-off-by: Mauro Carvalho Chehab
From: Marco Elver
Adds missing license and/or copyright headers for KCSAN source files.
Signed-off-by: Marco Elver
Signed-off-by: Paul E. McKenney
---
Documentation/dev-tools/kcsan.rst | 3 +++
include/linux/kcsan-checks.h | 6 ++
include/linux/kcsan.h | 7 +++
From: Marco Elver
Since KUnit now support parameterized tests via KUNIT_CASE_PARAM, update
KCSAN's test to switch to it for parameterized tests. This simplifies
parameterized tests and gets rid of the "parameters in case name"
workaround (hack).
At the same time, we can increase the maximum
From: Marco Elver
Commit 56348560d495 ("debugfs: do not attempt to create a new file
before the filesystem is initalized") forbids creating new debugfs files
until debugfs is fully initialized. This means that KCSAN's debugfs
file creation, which happened at the end of __init(), no longer
From: Marco Elver
Per recently added KUnit style recommendations at
Documentation/dev-tools/kunit/style.rst, make the following changes to
the KCSAN test:
1. Rename 'kcsan-test.c' to 'kcsan_test.c'.
2. Rename suite name 'kcsan-test' to 'kcsan'.
3. Rename
From: "Paul E. McKenney"
This commit adds a --duration argument to kvm-again.sh to allow the user
to override the --duration specified for the original kvm.sh run.
Signed-off-by: Paul E. McKenney
---
.../testing/selftests/rcutorture/bin/kvm-again.sh | 25 ++-
From: "Paul E. McKenney"
Some versions of grep are happy to interpret a nonsensically placed "-"
within a "[]" pattern as a dash, while others give an error message.
This commit therefore places the "-" at the end of the expression where
it was supposed to be in the first place.
Signed-off-by:
From: "Paul E. McKenney"
Because the TORTURE_TRUST_MAKE environment variable is not recorded,
kvm-again.sh runs can result in the parse-build.sh script emitting
false-positive "BUG: TREE03 no build" messages. These messages are
intended to complain about any lack of compiler invocations when
From: "Paul E. McKenney"
This commit creates a "batches" file in the res/$ds directory, where $ds
is the datestamp. This file contains the batches and the number of CPUs,
for example:
1 TREE03 16
1 SRCU-P 8
2 TREE07 16
2 TREE01 8
3 TREE02 8
3 TREE04 8
3 TREE05 8
4 SRCU-N 4
4 TRACE01 4
4
From: "Paul E. McKenney"
This commit enforces the defacto restriction on scenario names, which is
that they contain neither "/", ".", nor lowercase alphabetic characters.
This restriction avoids collisions between scenario names and the torture
scripting's files and directories.
Signed-off-by:
From: "Paul E. McKenney"
The cpus2use.sh script complains if the mpstat command is not available,
and instead uses all available CPUs. Unfortunately, this complaint
goes to stdout, where it confuses invokers who expect a single number.
This commit removes this error message in order to avoid
From: "Paul E. McKenney"
Distributed runs of rcutorture will need to start and stop jittering on
the remote hosts, which means that the commands must be communicated to
those hosts. The commit therefore causes kvm.sh to place these commands
in new TORTURE_JITTER_START and TORTURE_JITTER_STOP
From: "Paul E. McKenney"
The kvm-again.sh script does not copy over the vmlinux files due to
their large size. This means that a gdb run must use the vmlinux file
from the original "res" directory. This commit therefore finds that
directory and prints it out so that the user can copy and
From: "Paul E. McKenney"
When rerunning an old run using kvm-again.sh, the jitter commands
will re-use the original "res" directory. This works, but is clearly
an accident waiting to happen. And this accident will happen with
remote runs, where the original directory lives on some other
From: "Paul E. McKenney"
Currently, kvm-again.sh updates the duration in the "seconds=" comment
in the qemu-cmd file, but kvm-transform.sh updates the duration in the
actual qemu command arguments. This is an accident waiting to happen.
This commit therefore consolidates these updates into
From: "Paul E. McKenney"
This commit adds a kvm-again.sh script that, given the results directory
of a torture-test run, re-runs that test. This means that the kernels
need not be rebuilt, but it also is a step towards running torture tests
on remote systems.
This commit also adds a
From: "Paul E. McKenney"
The convention that scenario names are all uppercase has two exceptions,
SRCU-t and SRCU-u. This commit therefore renames them to SRCU-T and
SRCU-U, respectively, to bring them in line with this convention. This in
turn permits tighter argument checking in the
From: "Paul E. McKenney"
Although it might be unlikely that someone would name a scenario
"TORTURE_SUITE", they are within their rights to do so. This script
therefore renames the "TORTURE_SUITE" file in the top-level date-stamped
directory within "res" to "torture_suite" to avoid this name
From: "Paul E. McKenney"
This commit creates jitterstart.sh and jitterstop.sh scripts that handle
the starting and stopping of the jitter.sh scripts. These must be sourced
using the bash "." command to allow the generated script to wait on the
backgrounded jitter.sh scripts.
Signed-off-by:
From: "Paul E. McKenney"
Now that there is a reliable way to convince the jitter.sh scripts to
stop, the jitter_pids file is not needed, nor is the code that kills all
the PIDs contained in this file. This commit therefore eliminates this
file and the code using it.
Signed-off-by: Paul E.
From: "Paul E. McKenney"
Currently, the script generated by kvm.sh does a "wait" to wait on both
the current batch's guest OSes and any jitter.sh scripts. This works,
but makes it hard to abstract the jittering so that common code can be
used for both local and distributed runs. This commit
From: "Paul E. McKenney"
When re-running old rcutorture builds, if the original run involved
gdb, the re-run also needs to do so. This commit therefore records the
TORTURE_KCONFIG_GDB_ARG environment variable into the qemu-cmd file so
that the re-run can access it.
Signed-off-by: Paul E.
From: "Paul E. McKenney"
Currently, jitter.sh execution is controlled by a time limit and by the
"kill" command. The former allowed jitter.sh to run uselessly past
the end of a set of runs that panicked during boot, and the latter is
vulnerable to PID reuse. This commit therefore introduces a
From: "Paul E. McKenney"
Remote rcutorture testing requires that jitter.sh continue to be
invoked from the generated script for local runs, but that it instead
be invoked on the remote system for distributed runs. This argues
for common jitterstart and jitterstop scripts. But it would be good
From: "Paul E. McKenney"
Given large numbers of threads, the quantity of torture-test output is
sufficient to sometimes result in RCU CPU stall warnings. The probability
of these stall warnings was greatly reduced by batching the output,
but the warnings were not eliminated. However, the
From: "Paul E. McKenney"
Currently the bN.ready and bN.wait files are placed in the
rcutorture directory, which really is not at all a good place
for run-specific files. This commit therefore renames these
files to build.ready and build.wait and then moves them into the
scenario directories
From: "Paul E. McKenney"
The testid.txt file was intended for occasional in extremis use, but
now that the new "bare-metal" file references it, it might see more use.
This commit therefore labels sections of output and adds spacing to make
it easier to see what needs to be done to make a
From: "Paul E. McKenney"
This commit records the process IDs of the kvm-test-1-run.sh and
kvm-test-1-run-qemu.sh scripts to ease monitoring of remotely running
instances of these scripts.
Signed-off-by: Paul E. McKenney
---
tools/testing/selftests/rcutorture/bin/kvm-test-1-run-qemu.sh | 2 ++
From: "Paul E. McKenney"
Currently, kvm-test-1-run.sh both builds and runs an rcutorture kernel,
which is inconvenient when it is necessary to re-run an old run or to
carry out a run on a remote system. This commit therefore extracts the
portion of kvm-test-1-run.sh that invoke qemu to actually
From: "Paul E. McKenney"
Given large numbers of threads, the quantity of torture-test output is
sufficient to sometimes result in RCU CPU stall warnings. The probability
of these stall warnings was greatly reduced by batching the output,
but the warnings were not eliminated. However, the
From: "Paul E. McKenney"
Yes, I do recall a time when 512MB of memory was a lot of mass storage,
much less main memory, but the rcuscale kvfree_rcu() testing invoked by
torture.sh can sometimes exceed it on large systems, resulting in OOM.
This commit therefore causes torture.sh to pase the
From: "Paul E. McKenney"
If the build fails when running multiple instances of a given rcutorture
scenario, for example, using the kvm.sh --configs "8*RUDE01" argument,
the build will be rerun an additional seven times. This is in some sense
correct, but it can waste significant time. This
From: "Paul E. McKenney"
In some environments, the torture-testing use of virtualization is
inconvenient. In such cases, the modprobe and rmmod commands may be used
to do torture testing, but significant setup is required to build, boot,
and modprobe a kernel so as to match a given torture-test
From: Stephen Zhang
This commit replaces a hard-coded "rcu_torture_stall" string in a
pr_alert() format with "%s" and __func__.
Signed-off-by: Stephen Zhang
Signed-off-by: Paul E. McKenney
---
kernel/rcu/rcutorture.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git
From: Stephen Zhang
This commit replaces a hard-coded "torture_init_begin" string in
a pr_alert() format with "%s" and __func__.
Signed-off-by: Stephen Zhang
Signed-off-by: Paul E. McKenney
---
kernel/torture.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git
From: Lukas Bulwahn
The command 'find ./kernel/rcu/ | xargs ./scripts/kernel-doc -none'
reported an issue with the kernel-doc of struct rcu_tasks.
This commit rectifies the kernel-doc, such that no issues remain for
./kernel/rcu/.
Signed-off-by: Lukas Bulwahn
Signed-off-by: Paul E. McKenney
y: Mathieu Desnoyers
[ paulmck: Fix commit log per Mathieu Desnoyers feedback. ]
Signed-off-by: Paul E. McKenney
---
kernel/rcu/tasks.h | 36
1 file changed, 36 insertions(+)
diff --git a/kernel/rcu/tasks.h b/kernel/rcu/tasks.h
index 17c8ebe..f818
From: "Paul E. McKenney"
The current jitter.sh script expects cpumask bits to fit into whatever
the awk interpreter uses for an integer, which clearly does not hold for
even medium-sized systems these days. This means that on a large system,
only the first 32 or 64 CPUs (depending) are
From: "Paul E. McKenney"
TREE03 tests RCU priority boosting, which is a real-time feature.
It would also be good if it tested something closer to what is
actually used by the real-time folks. This commit therefore adds
tree.use_softirq=0 to the TREE03 kernel boot parameters in TREE03.boot.
From: "Paul E. McKenney"
Currently, rcutorture refuses to test RCU priority boosting in
CONFIG_HOTPLUG_CPU=y kernels, which are the only kind normally built on
x86 these days. This commit therefore updates rcutorture's tests of RCU
priority boosting to make them safe for CPU hotplug. However,
From: "Paul E. McKenney"
In kernels built with CONFIG_RCU_STRICT_GRACE_PERIOD=y, every grace
period is an expedited grace period. However, rcu_read_unlock_special()
does not treat them that way, instead allowing the deferred quiescent
state to be reported whenever. This commit therefore adds a
From: "Paul E. McKenney"
Historically, a task that has been subjected to RCU priority boosting is
deboosted at rcu_read_unlock() time. However, with the advent of deferred
quiescent states, if the outermost rcu_read_unlock() was invoked with
either bottom halves, interrupts, or preemption
From: "Paul E. McKenney"
There is a need for a non-blocking polling interface for RCU grace
periods, so this commit supplies start_poll_synchronize_rcu() and
poll_state_synchronize_rcu() for this purpose. Note that the existing
get_state_synchronize_rcu() may be used if future grace periods are
From: "Paul E. McKenney"
This commit causes rcutorture to test the new start_poll_synchronize_rcu()
and poll_state_synchronize_rcu() functions. Because of the difficulty of
determining the nature of a synchronous RCU grace (expedited or not),
the test that insisted that
From: "Paul E. McKenney"
There is a need for a non-blocking polling interface for RCU grace
periods, so this commit supplies start_poll_synchronize_rcu() and
poll_state_synchronize_rcu() for this purpose. Note that the existing
get_state_synchronize_rcu() may be used if future grace periods are
From: Frederic Weisbecker
Those tracing calls don't need to be under ->nocb_lock. This commit
therefore moves them outside of that lock.
Signed-off-by: Frederic Weisbecker
Cc: Josh Triplett
Cc: Lai Jiangshan
Cc: Joel Fernandes
Cc: Neeraj Upadhyay
Cc: Boqun Feng
Signed-off-by: Paul E.
From: Jiapeng Chong
RCU triggerse the following sparse warning:
kernel/rcu/tree_plugin.h:1497:5: warning: symbol
'nocb_nobypass_lim_per_jiffy' was not declared. Should it be static?
This commit therefore makes this variable static.
Reported-by: Abaci Robot
Frederic Weisbecker
Signed-off-by:
From: Frederic Weisbecker
This sequence of events can lead to a failure to requeue a CPU's
->nocb_timer:
1. There are no callbacks queued for any CPU covered by CPU 0-2's
->nocb_gp_kthread. Note that ->nocb_gp_kthread is associated
with CPU 0.
2. CPU 1 enqueues its
From: Frederic Weisbecker
This commit removes a stale comment claiming that the cblist must be
empty before changing the offloading state. This claim was correct back
when the offloaded state was defined exclusively at boot.
Reported-by: Paul E. McKenney
Signed-off-by: Frederic Weisbecker
From: Frederic Weisbecker
The name nocb_gp_update_state() is unenlightening, so this commit changes
it to nocb_gp_update_state_deoffloading(). This function now does what
its name says, updates state and returns true if the CPU corresponding to
the specified rcu_data structure is in the process
From: Frederic Weisbecker
Currently, the bypass is flushed at the very last moment in the
deoffloading procedure. However, this approach leads to a larger state
space than would be preferred. This commit therefore disables the
bypass at soon as the deoffloading procedure begins, then flushes
From: Frederic Weisbecker
At the start of a CPU-hotplug operation, the incoming CPU's callback
list can be in a number of states:
1. Disabled and empty. This is the case when the boot CPU has
not invoked call_rcu(), when a non-boot CPU first comes online,
and when a
From: Frederic Weisbecker
The nocb_cb_wait() function first sets the rdp->nocb_cb_sleep flag to
true by after invoking the callbacks, and then sets it back to false if
it finds more callbacks that are ready to invoke.
This is confusing and will become unsafe if this flag is ever read
From: Frederic Weisbecker
It makes no sense to de-offload an offline CPU because that CPU will never
invoke any remaining callbacks. It also makes little sense to offload an
offline CPU because any pending RCU callbacks were migrated when that CPU
went offline. Yes, it is in theory possible to
From: Frederic Weisbecker
Provide CONFIG_PROVE_RCU sanity checks to ensure we are always reading
the offloaded state of an rdp in a safe and stable way and prevent from
its value to be changed under us. We must either hold the barrier mutex,
the cpu-hotplug lock (read or write) or the nocb lock.
From: Frederic Weisbecker
This commit explains why softirqs need to be disabled while invoking
callbacks, even when callback processing has been offloaded. After
all, invoking callbacks concurrently is one thing, but concurrently
invoking the same callback is quite another.
Reported-by: Boqun
From: Frederic Weisbecker
Enqueuing a local timer after the tick has been stopped will result in
the timer being ignored until the next random interrupt.
Perform sanity checks to report these situations.
Cc: Peter Zijlstra
Cc: Thomas Gleixner
Cc: Ingo Molnar
Cc: Rafael J. Wysocki
From: Paul Gortmaker
It makes sense to do all the checks in check_region() and not 1/2
in check_region and 1/2 in set_region.
Since set_region is called immediately after check_region, the net
effect on runtime is zero, but it gets rid of an if (...) return...
Cc: Yury Norov
Cc: Rasmus
From: Paul Gortmaker
This will reduce parameter passing and enable using nbits as part
of future dynamic region parameter parsing.
Cc: Yury Norov
Cc: Rasmus Villemoes
Cc: Andy Shevchenko
Suggested-by: Yury Norov
Acked-by: Yury Norov
Reviewed-by: Andy Shevchenko
Signed-off-by: Paul
From: Paul Gortmaker
Add tests that specify a valid range, but one that is outside the
width of the bitmap for which it is to be applied to. These should
trigger an -ERANGE response from the code.
Cc: Yury Norov
Cc: Rasmus Villemoes
Cc: Andy Shevchenko
Acked-by: Yury Norov
Reviewed-by:
From: Paul Gortmaker
This block of tests was meant to find/flag incorrect use of the ":"
and "/" separators (syntax errors) and invalid (zero) group len.
However they were specified with an 8 bit width and 32 bit operations,
so they really contained two errors (EINVAL and ERANGE).
Promote them
From: Paul Gortmaker
These are copies of existing tests, with just 31 --> N. This ensures
the recently added "N" alias transparently works in any normally
numeric fields of a region specification.
Cc: Yury Norov
Cc: Rasmus Villemoes
Cc: Andy Shevchenko
Acked-by: Yury Norov
Signed-off-by:
From: "Paul E. McKenney"
This commit uses the shiny new "all" and "N" cpumask options to decouple
the "nohz_full" and "rcu_nocbs" kernel boot parameters in the TREE04.boot
and TREE08.boot files from the CONFIG_NR_CPUS options in the TREE04 and
TREE08 files.
Reported-by: Paul Gortmaker
From: Paul Gortmaker
With the core bitmap support now accepting "N" as a placeholder for
the end of the bitmap, "all" can be represented as "0-N" and has the
advantage of not being specific to RCU (or any other subsystem).
So deprecate the use of "all" by removing documentation references
to
From: Paul Gortmaker
While this is done for all bitmaps, the original use case in mind was
for CPU masks and cpulist_parse() as described below.
It seems that a common configuration is to use the 1st couple cores for
housekeeping tasks. This tends to leave the remaining ones to form a
pool of
From: Paul Gortmaker
There are inputs to bitmap_parselist() that would probably never
be entered manually by a person, but might result from some kind of
automated input generator. Things like ranges of length 1, or group
lengths longer than nbits, overlaps, or offsets of zero.
Adding these
u(), given that the double-argument variant cannot directly
invoke the allocator.
[ paulmck: Add add_ptr_to_bulk_krc_lock header comment per Michal Hocko. ]
Signed-off-by: Uladzislau Rezki (Sony)
Signed-off-by: Paul E. McKenney
---
kernel/rcu/tree.c | 42 ++--
From: "Paul E. McKenney"
The krc_this_cpu_unlock() function does a raw_spin_unlock() immediately
followed by a local_irq_restore(). This commit saves a line of code by
merging them into a raw_spin_unlock_irqrestore(). This transformation
also reduces scheduling latency because
From: "Uladzislau Rezki (Sony)"
Running an rcuscale stress-suite can lead to "Out of memory" of a
system. This can happen under high memory pressure with a small amount
of physical memory.
For example, a KVM test configuration with 64 CPUs and 512 megabytes
can result in OOM when running
From: "Uladzislau Rezki (Sony)"
__GFP_RETRY_MAYFAIL can spend quite a bit of time reclaiming, and this
can be wasted effort given that there is a fallback code path in case
memory allocation fails.
__GFP_NORETRY does perform some light-weight reclaim, but it will fail
under OOM conditions,
From: "Uladzislau Rezki (Sony)"
The single-argument variant of kfree_rcu() is currently not
tested by any member of the rcutoture test suite. This
commit therefore adds rcuscale code to test it. This
testing is controlled by two new boolean module parameters,
kfree_rcu_test_single and
From: "Paul E. McKenney"
This commit applies the __GFP_NOMEMALLOC gfp flag to memory allocations
carried out by the single-argument variant of kvfree_rcu(), thus avoiding
this can-sleep code path from dipping into the emergency reserves.
Acked-by: Michal Hocko
Suggested-by: Michal Hocko
au Rezki
Cc: Peter Zijlstra
Cc: Thomas Gleixner
[ paulmck: Remove unneeded check per Sebastian Siewior feedback. ]
Signed-off-by: Paul E. McKenney
---
kernel/softirq.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/softirq.c b/kernel/softirq.c
index 9908ec4a..bad14ca 10
From: "Paul E. McKenney"
This commit replaces "Steve" with the his real name, which is "Stephen".
Reported-by: Stephen Hemminger
Signed-off-by: Paul E. McKenney
---
Documentation/RCU/RTFP.txt | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/Documentation/RCU/RTFP.txt
From: Sangmoon Kim
This commit adds a trace event which allows tracing the beginnings of RCU
CPU stall warnings on systems where sysctl_panic_on_rcu_stall is disabled.
The first parameter is the name of RCU flavor like other trace events.
The second parameter indicates whether this is a stall
From: "Paul E. McKenney"
After interrupts have enabled at boot but before some random point
in early_initcall() processing, softirq processing is unreliable.
If softirq sees a need to push softirq-handler invocation to ksoftirqd
during this time, then those handlers can be delayed until the
From: "Paul E. McKenney"
Because preemptible RCU's __rcu_read_unlock() is an external function,
the rough equivalent of an implicit barrier() is inserted by the compiler.
Except that there is a direct call to __rcu_read_unlock() in that same
file, and compilers are getting to the point where
From: Mauro Carvalho Chehab
After commit 5130b8fd0690 ("rcu: Introduce kfree_rcu() single-argument macro"),
kernel-doc now emits two warnings:
./include/linux/rcupdate.h:884: warning: Excess function parameter
'ptr' description in 'kfree_rcu'
./include/linux/rcupdate.h:884:
From: Neeraj Upadhyay
The condition in the trace_rcu_grace_period() in rcutree_dying_cpu() is
backwards, so that it uses the string "cpuofl" when the offline CPU is
blocking the current grace period and "cpuofl-bgp" otherwise. Given that
the "-bgp" stands for "blocking grace period", this is at
From: Zhouyi Zhou
In rcu_nmi_enter(), there is an erroneous instrumentation_end() in the
second branch of the "if" statement. Oddly enough, "objtool check -f
vmlinux.o" fails to complain because it is unable to correctly cover
all cases. Instead, objtool visits the third branch first, which
From: Frederic Weisbecker
Cc: Rafael J. Wysocki
Cc: Peter Zijlstra
Cc: Thomas Gleixner
Cc: Ingo Molnar
Signed-off-by: Frederic Weisbecker
Signed-off-by: Paul E. McKenney
---
kernel/rcu/tree.c | 1 -
1 file changed, 1 deletion(-)
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index
From: Akira Yokosawa
The hlist_nulls_for_each_entry_rcu() docbook header references the
atomic_ops.rst file, which was removed in commit f0400a77ebdc ("atomic:
Delete obsolete documentation"). This commit therefore substitutes a
section in memory-barriers.txt discussing the use of barrier() in
determine whether to add or
to subtract.
Cc: John Stultz
Cc: Thomas Gleixner
Cc: Stephen Boyd
Cc: Jonathan Corbet
Cc: Mark Rutland
Cc: Marc Zyngier
Cc: Andi Kleen
Reported-by: Chris Mason
[ paulmck: Apply Randy Dunlap feedback. ]
Signed-off-by: Paul E. McKenney
---
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