Paul E. McKenney [Thu, 25 Mar 2021 00:20:18 +0000 (17:20 -0700)]
Merge branches 'bitmaprange.2021.03.08a', 'fixes.2021.03.15a', 'kvfree_rcu.2021.03.08a', 'mmdumpobj.2021.03.08a', 'nocb.2021.03.15a', 'poll.2021.03.24a', 'rt.2021.03.08a', 'tasks.2021.03.08a', 'torture.2021.03.08a' and 'torturescript.2021.03.22a' into HEAD
bitmaprange.2021.03.08a: Allow 3-N for bitmap ranges.
fixes.2021.03.15a: Miscellaneous fixes.
kvfree_rcu.2021.03.08a: kvfree_rcu() updates.
mmdumpobj.2021.03.08a: mem_dump_obj() updates.
nocb.2021.03.15a: RCU NOCB CPU updates, including limited deoffloading.
poll.2021.03.24a: Polling grace-period interfaces for RCU.
rt.2021.03.08a: Realtime-related RCU changes.
tasks.2021.03.08a: Tasks-RCU updates.
torture.2021.03.08a: Torture-test updates.
torturescript.2021.03.22a: Torture-test scripting updates.
Paul E. McKenney [Fri, 26 Feb 2021 04:56:10 +0000 (20:56 -0800)]
rcutorture: Test start_poll_synchronize_rcu() and poll_state_synchronize_rcu()
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 poll_state_synchronize_rcu() detect an
intervening synchronize_rcu() had to be dropped.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Paul E. McKenney [Fri, 26 Feb 2021 01:36:06 +0000 (17:36 -0800)]
rcu: Provide polling interfaces for Tiny RCU grace periods
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
inevitable (perhaps due to a later call_rcu() invocation). The new
start_poll_synchronize_rcu() is to be used if future grace periods
might not otherwise happen. Finally, poll_state_synchronize_rcu()
provides a lockless check for a grace period having elapsed since
the corresponding call to either of the get_state_synchronize_rcu()
or start_poll_synchronize_rcu().
As with get_state_synchronize_rcu(), the return value from either
get_state_synchronize_rcu() or start_poll_synchronize_rcu() is passed in
to a later call to either poll_state_synchronize_rcu() or the existing
(might_sleep) cond_synchronize_rcu().
[ paulmck: Revert cond_synchronize_rcu() to might_sleep() per Frederic Weisbecker feedback. ]
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Paul E. McKenney [Sun, 28 Feb 2021 04:55:57 +0000 (20:55 -0800)]
torture: Fix kvm.sh --datestamp regex check
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: Paul E. McKenney <paulmck@kernel.org>
Paul E. McKenney [Tue, 23 Feb 2021 22:33:03 +0000 (14:33 -0800)]
torture: Consolidate qemu-cmd duration editing into kvm-transform.sh
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 kvm-transform.sh.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Paul E. McKenney [Tue, 23 Feb 2021 21:12:41 +0000 (13:12 -0800)]
torture: Print proper vmlinux path for kvm-again.sh runs
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 pasted the
gdb command just as for the initial run.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Paul E. McKenney [Tue, 23 Feb 2021 20:07:39 +0000 (12:07 -0800)]
torture: Make TORTURE_TRUST_MAKE available in kvm-again.sh environment
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 the
--trust-make flag is not given to kvm.sh. However, when this flag is
given to kvm.sh (and thus when TORTURE_TRUST_MAKE=y), lack of compiler
invocations is expected behavior when rebuilding from identical source
code.
This commit therefore makes kvm-test-1-run.sh record the value of the
TORTURE_TRUST_MAKE environment variable as an additional comment in the
qemu-cmd file, and also makes kvm-again.sh reconstitute that variable
from that comment.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Paul E. McKenney [Mon, 22 Feb 2021 22:58:41 +0000 (14:58 -0800)]
torture: Make kvm-transform.sh update jitter commands
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 system.
This commit therefore updates the qemu-cmd commands to use the new res
directory created for this specific run.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Paul E. McKenney [Mon, 22 Feb 2021 22:12:58 +0000 (14:12 -0800)]
torture: Add --duration argument to kvm-again.sh
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 <paulmck@kernel.org>
Paul E. McKenney [Sat, 20 Feb 2021 01:49:58 +0000 (17:49 -0800)]
torture: Add kvm-again.sh to rerun a previous torture-test
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 kvm-test-1-run-batch.sh script that runs one
batch out of the torture test. The idea is to copy a results directory
tree to remote systems, then use kvm-test-1-run-batch.sh to run batches
on these systems.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Paul E. McKenney [Wed, 17 Feb 2021 22:40:03 +0000 (14:40 -0800)]
torture: Create a "batches" file for build reuse
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 TRACE02 4
4 RUDE01 2
4 RUDE01.2 2
4 TASKS01 2
4 TASKS03 2
4 SRCU-t 1
4 SRCU-u 1
4 TASKS02 1
4 TINY01 1
5 TINY02 1
5 TREE09 1
The first column is the batch number, the second the scenario number
(possibly suffixed by a repetition number, as in "RUDE01.2"), and the
third is the number of CPUs required by that scenario. The last line
shows the number of CPUs expected by this batch file, which allows
the run to be re-batched if a different number of CPUs is available.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Paul E. McKenney [Wed, 17 Feb 2021 22:04:01 +0000 (14:04 -0800)]
torture: De-capitalize TORTURE_SUITE
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 collision.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Paul E. McKenney [Wed, 17 Feb 2021 15:15:41 +0000 (07:15 -0800)]
torture: Make upper-case-only no-dot no-slash scenario names official
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: Paul E. McKenney <paulmck@kernel.org>
Paul E. McKenney [Sat, 20 Feb 2021 18:13:52 +0000 (10:13 -0800)]
torture: Rename SRCU-t and SRCU-u to avoid lowercase characters
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 torture-test scripting.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Paul E. McKenney [Wed, 17 Feb 2021 04:17:44 +0000 (20:17 -0800)]
torture: Remove no-mpstat error message
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 this confusion.
The tendency of late has been to give rcutorture a full system, so this
should not cause issues.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Paul E. McKenney [Wed, 17 Feb 2021 00:55:04 +0000 (16:55 -0800)]
torture: Record kvm-test-1-run.sh and kvm-test-1-run-qemu.sh PIDs
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 <paulmck@kernel.org>
Paul E. McKenney [Tue, 16 Feb 2021 23:32:23 +0000 (15:32 -0800)]
torture: Record jitter start/stop commands
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 environment variables
to communicate them to the scripts that will set this up. In addition,
this commit causes kvm-test-1-run.sh to append these commands to each
generated qemu-cmd file, which allows any remotely executing script to
extract the needed commands from this file.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Paul E. McKenney [Fri, 12 Feb 2021 22:00:05 +0000 (14:00 -0800)]
torture: Extract kvm-test-1-run-qemu.sh from kvm-test-1-run.sh
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 run rcutorture
and places it in kvm-test-1-run-qemu.sh.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Paul E. McKenney [Fri, 12 Feb 2021 00:19:29 +0000 (16:19 -0800)]
torture: Record TORTURE_KCONFIG_GDB_ARG in qemu-cmd
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. McKenney <paulmck@kernel.org>
Paul E. McKenney [Thu, 11 Feb 2021 20:37:46 +0000 (12:37 -0800)]
torture: Abstract jitter.sh start/stop into scripts
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: Paul E. McKenney <paulmck@kernel.org>
Paul E. McKenney [Fri, 26 Feb 2021 00:10:38 +0000 (16:10 -0800)]
rcu: Provide polling interfaces for Tree RCU grace periods
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
inevitable (perhaps due to a later call_rcu() invocation). The new
start_poll_synchronize_rcu() is to be used if future grace periods
might not otherwise happen. Finally, poll_state_synchronize_rcu()
provides a lockless check for a grace period having elapsed since
the corresponding call to either of the get_state_synchronize_rcu()
or start_poll_synchronize_rcu().
As with get_state_synchronize_rcu(), the return value from either
get_state_synchronize_rcu() or start_poll_synchronize_rcu() is passed in
to a later call to either poll_state_synchronize_rcu() or the existing
(might_sleep) cond_synchronize_rcu().
[ paulmck: Remove redundant smp_mb() per Frederic Weisbecker feedback. ]
[ Update poll_state_synchronize_rcu() docbook per Frederic Weisbecker feedback. ]
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Frederic Weisbecker [Tue, 23 Feb 2021 00:10:02 +0000 (01:10 +0100)]
rcu/nocb: Move trace_rcu_nocb_wake() calls outside nocb_lock when possible
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 <frederic@kernel.org>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: Neeraj Upadhyay <neeraju@codeaurora.org>
Cc: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Frederic Weisbecker [Tue, 23 Feb 2021 00:10:01 +0000 (01:10 +0100)]
rcu/nocb: Remove stale comment above rcu_segcblist_offload()
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 <paulmck@kernel.org>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: Neeraj Upadhyay <neeraju@codeaurora.org>
Cc: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Frederic Weisbecker [Tue, 23 Feb 2021 00:10:00 +0000 (01:10 +0100)]
rcu/nocb: Disable bypass when CPU isn't completely offloaded
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 it.
This guarantees that the bypass remains empty and thus out of the way
of the deoffloading procedure.
Symmetrically, this commit waits to enable the bypass until the offloading
procedure has completed.
Reported-by: Paul E. McKenney <paulmck@kernel.org>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: Neeraj Upadhyay <neeraju@codeaurora.org>
Cc: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Frederic Weisbecker [Tue, 23 Feb 2021 00:09:59 +0000 (01:09 +0100)]
rcu/nocb: Fix missed nocb_timer requeue
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 first callback with interrupts disabled, and
thus must defer awakening its ->nocb_gp_kthread. It therefore
queues its rcu_data structure's ->nocb_timer. At this point,
CPU 1's rdp->nocb_defer_wakeup is RCU_NOCB_WAKE.
3. CPU 2, which shares the same ->nocb_gp_kthread, also enqueues a
callback, but with interrupts enabled, allowing it to directly
awaken the ->nocb_gp_kthread.
4. The newly awakened ->nocb_gp_kthread associates both CPU 1's
and CPU 2's callbacks with a future grace period and arranges
for that grace period to be started.
5. This ->nocb_gp_kthread goes to sleep waiting for the end of this
future grace period.
6. This grace period elapses before the CPU 1's timer fires.
This is normally improbably given that the timer is set for only
one jiffy, but timers can be delayed. Besides, it is possible
that kernel was built with CONFIG_RCU_STRICT_GRACE_PERIOD=y.
7. The grace period ends, so rcu_gp_kthread awakens the
->nocb_gp_kthread, which in turn awakens both CPU 1's and
CPU 2's ->nocb_cb_kthread. Then ->nocb_gb_kthread sleeps
waiting for more newly queued callbacks.
8. CPU 1's ->nocb_cb_kthread invokes its callback, then sleeps
waiting for more invocable callbacks.
9. Note that neither kthread updated any ->nocb_timer state,
so CPU 1's ->nocb_defer_wakeup is still set to RCU_NOCB_WAKE.
10. CPU 1 enqueues its second callback, this time with interrupts
enabled so it can wake directly ->nocb_gp_kthread.
It does so with calling wake_nocb_gp() which also cancels the
pending timer that got queued in step 2. But that doesn't reset
CPU 1's ->nocb_defer_wakeup which is still set to RCU_NOCB_WAKE.
So CPU 1's ->nocb_defer_wakeup and its ->nocb_timer are now
desynchronized.
11. ->nocb_gp_kthread associates the callback queued in 10 with a new
grace period, arranges for that grace period to start and sleeps
waiting for it to complete.
12. The grace period ends, rcu_gp_kthread awakens ->nocb_gp_kthread,
which in turn wakes up CPU 1's ->nocb_cb_kthread which then
invokes the callback queued in 10.
13. CPU 1 enqueues its third callback, this time with interrupts
disabled so it must queue a timer for a deferred wakeup. However
the value of its ->nocb_defer_wakeup is RCU_NOCB_WAKE which
incorrectly indicates that a timer is already queued. Instead,
CPU 1's ->nocb_timer was cancelled in 10. CPU 1 therefore fails
to queue the ->nocb_timer.
14. CPU 1 has its pending callback and it may go unnoticed until
some other CPU ever wakes up ->nocb_gp_kthread or CPU 1 ever
calls an explicit deferred wakeup, for example, during idle entry.
This commit fixes this bug by resetting rdp->nocb_defer_wakeup everytime
we delete the ->nocb_timer.
It is quite possible that there is a similar scenario involving
->nocb_bypass_timer and ->nocb_defer_wakeup. However, despite some
effort from several people, a failure scenario has not yet been located.
However, that by no means guarantees that no such scenario exists.
Finding a failure scenario is left as an exercise for the reader, and the
"Fixes:" tag below relates to ->nocb_bypass_timer instead of ->nocb_timer.
Fixes:
d1b222c6be1f (rcu/nocb: Add bypass callback queueing)
Cc: <stable@vger.kernel.org>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: Boqun Feng <boqun.feng@gmail.com>
Reviewed-by: Neeraj Upadhyay <neeraju@codeaurora.org>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Jiapeng Chong [Wed, 24 Feb 2021 08:30:29 +0000 (16:30 +0800)]
rcu: Make nocb_nobypass_lim_per_jiffy static
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 <abaci@linux.alibaba.com>
Reported-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Sangmoon Kim [Tue, 2 Mar 2021 11:55:15 +0000 (20:55 +0900)]
rcu/tree: Add a trace event for RCU CPU stall warnings
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 of an expedited
grace period, a self-detected stall of a normal grace period, or a stall
of a normal grace period detected by some CPU other than the one that
is stalled.
RCU CPU stall warnings are often caused by external-to-RCU issues,
for example, in interrupt handling or task scheduling. Therefore,
this event uses TRACE_EVENT, not TRACE_EVENT_RCU, to avoid requiring
those interested in tracing RCU CPU stalls to rebuild their kernels
with CONFIG_RCU_TRACE=y.
Reviewed-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Reviewed-by: Neeraj Upadhyay <neeraju@codeaurora.org>
Signed-off-by: Sangmoon Kim <sangmoon.kim@samsung.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Paul E. McKenney [Fri, 26 Feb 2021 19:25:29 +0000 (11:25 -0800)]
rcu: Add explicit barrier() to __rcu_read_unlock()
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 they might choose to
inline the fastpath of the __rcu_read_unlock() function.
This commit therefore adds an explicit barrier() to the very beginning
of __rcu_read_unlock().
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Paul E. McKenney [Tue, 23 Feb 2021 18:07:09 +0000 (10:07 -0800)]
docs: Correctly spell Stephen Hemminger's name
This commit replaces "Steve" with the his real name, which is "Stephen".
Reported-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Paul E. McKenney [Sat, 13 Feb 2021 00:20:40 +0000 (16:20 -0800)]
softirq: Don't try waking ksoftirqd before it has been spawned
If there is heavy softirq activity, the softirq system will attempt
to awaken ksoftirqd and will stop the traditional back-of-interrupt
softirq processing. This is all well and good, but only if the
ksoftirqd kthreads already exist, which is not the case during early
boot, in which case the system hangs.
One reproducer is as follows:
tools/testing/selftests/rcutorture/bin/kvm.sh --allcpus --duration 2 --configs "TREE03" --kconfig "CONFIG_DEBUG_LOCK_ALLOC=y CONFIG_PROVE_LOCKING=y CONFIG_NO_HZ_IDLE=y CONFIG_HZ_PERIODIC=n" --bootargs "threadirqs=1" --trust-make
This commit therefore adds a couple of existence checks for ksoftirqd
and forces back-of-interrupt softirq processing when ksoftirqd does not
yet exist. With this change, the above test passes.
Reported-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reported-by: Uladzislau Rezki <urezki@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
[ paulmck: Remove unneeded check per Sebastian Siewior feedback. ]
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Paul E. McKenney [Thu, 11 Feb 2021 19:54:43 +0000 (11:54 -0800)]
torture: Reverse jittering and duration parameters for jitter.sh
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
for jitterstart and jitterstop to control the name and location of the
"jittering" file, while continuing to have the duration controlled by
the caller of these new scripts.
This commit therefore reverses the order of the jittering and duration
parameters for jitter.sh, so that the jittering parameter precedes the
duration parameter.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Paul E. McKenney [Thu, 11 Feb 2021 18:56:42 +0000 (10:56 -0800)]
torture: Eliminate jitter_pids file
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. McKenney <paulmck@kernel.org>
Paul E. McKenney [Thu, 11 Feb 2021 18:39:28 +0000 (10:39 -0800)]
torture: Use "jittering" file to control jitter.sh execution
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 "jittering"
file in the date-stamp directory within "res" that must be present for
the jitter.sh scripts to continue executing. The time limit is still
in place in order to avoid disturbing runs featuring large trace dumps,
but the removal of the "jittering" file handles the panic-during-boot
scenario without relying on PIDs.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Paul E. McKenney [Thu, 11 Feb 2021 00:28:44 +0000 (16:28 -0800)]
torture: Use file-based protocol to mark batch's runs complete
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 therefore uses
"build.run" files in scenario directories, and these files are removed
after the corresponding scenario's guest OS has completed.
Note that --build-only runs do not create build.run files because they
also do not create guest OSes and do not run any jitter.sh scripts.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Paul E. McKenney [Wed, 10 Feb 2021 23:15:13 +0000 (15:15 -0800)]
torture: Move build/run synchronization files into scenario directories
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 within the "res" directory, for example, into
tools/testing/selftests/rcutorture/res/2021.02.10-15.08.23/TINY01.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Paul E. McKenney [Thu, 28 Jan 2021 18:17:26 +0000 (10:17 -0800)]
refscale: Disable verbose torture-test output
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 actual test only
depends on console output that is printed even when refscale.verbose=0.
This commit therefore causes this test to run with refscale.verbose=0.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Paul E. McKenney [Thu, 28 Jan 2021 18:15:02 +0000 (10:15 -0800)]
rcuscale: Disable verbose torture-test output
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 actual test only
depends on console output that is printed even when rcuscale.verbose=0.
This commit therefore causes this test to run with rcuscale.verbose=0.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Paul E. McKenney [Fri, 5 Feb 2021 01:20:45 +0000 (17:20 -0800)]
torture: Improve readability of the testid.txt file
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 bare-metal build tree
match an rcutorture build tree.
Of course, you can avoid this whole issue by building your bare-metal
kernel in the same directory in which you ran rcutorture, but that might
not always be an option.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Paul E. McKenney [Wed, 3 Feb 2021 23:44:29 +0000 (15:44 -0800)]
torture: Provide bare-metal modprobe-based advice
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 scenario.
This commit therefore creates a "bare-metal" file in each results
directory containing steps to run the corresponding scenario using the
modprobe command on bare metal. For example, the contents of this file
after using kvm.sh to build an rcutorture TREE01 kernel, perhaps with
the --buildonly argument, is as follows:
To run this scenario on bare metal:
1. Set your bare-metal build tree to the state shown in this file:
/home/git/linux-rcu/tools/testing/selftests/rcutorture/res/2021.02.04-17.10.19/testid.txt
2. Update your bare-metal build tree's .config based on this file:
/home/git/linux-rcu/tools/testing/selftests/rcutorture/res/2021.02.04-17.10.19/TREE01/ConfigFragment
3. Make the bare-metal kernel's build system aware of your .config updates:
$ yes "" | make oldconfig
4. Build your bare-metal kernel.
5. Boot your bare-metal kernel with the following parameters:
maxcpus=8 nr_cpus=43 rcutree.gp_preinit_delay=3 rcutree.gp_init_delay=3 rcutree.gp_cleanup_delay=3 rcu_nocbs=0-1,3-7
6. Start the test with the following command:
$ modprobe rcutorture nocbs_nthreads=8 nocbs_toggle=1000 fwd_progress=0 onoff_interval=1000 onoff_holdoff=30 n_barrier_cbs=4 stat_interval=15 shutdown_secs=120 test_no_idle_hz=1 verbose=1
7. After some time, end the test with the following command:
$ rmmod rcutorture
8. Copy your bare-metal kernel's .config file, overwriting this file:
/home/git/linux-rcu/tools/testing/selftests/rcutorture/res/2021.02.04-17.10.19/TREE01/.config
9. Copy the console output from just before the modprobe to just after
the rmmod into this file:
/home/git/linux-rcu/tools/testing/selftests/rcutorture/res/2021.02.04-17.10.19/TREE01/console.log
10. Check for runtime errors using the following command:
$ tools/testing/selftests/rcutorture/bin/kvm-recheck.sh /home/git/linux-rcu/tools/testing/selftests/rcutorture/res/2021.02.04-17.10.19
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Paul E. McKenney [Fri, 29 Jan 2021 00:38:19 +0000 (16:38 -0800)]
torture: Allow 1G of memory for torture.sh kvfree testing
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 "--memory 1G"
argument to kvm.sh to reserve a full gigabyte for this purpose.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Paul E. McKenney [Tue, 5 Jan 2021 18:50:32 +0000 (10:50 -0800)]
torturescript: Don't rerun failed rcutorture builds
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 commit therefore checks
for a prior failed build and simply copies over that build's output.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Stephen Zhang [Sat, 23 Jan 2021 09:54:17 +0000 (17:54 +0800)]
rcutorture: Replace rcu_torture_stall string with %s
This commit replaces a hard-coded "rcu_torture_stall" string in a
pr_alert() format with "%s" and __func__.
Signed-off-by: Stephen Zhang <stephenzhangzsd@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Stephen Zhang [Sat, 23 Jan 2021 08:34:01 +0000 (16:34 +0800)]
torture: Replace torture_init_begin string with %s
This commit replaces a hard-coded "torture_init_begin" string in
a pr_alert() format with "%s" and __func__.
Signed-off-by: Stephen Zhang <stephenzhangzsd@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Paul E. McKenney [Thu, 25 Feb 2021 18:26:00 +0000 (10:26 -0800)]
rcu-tasks: Add block comment laying out RCU Tasks Trace design
This commit adds a block comment that gives a high-level overview of
how RCU tasks trace grace periods progress. It also adds a note about
how exiting tasks are handled, plus it gives an overview of the memory
ordering.
Reported-by: Peter Zijlstra <peterz@infradead.org>
Reported-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
[ paulmck: Fix commit log per Mathieu Desnoyers feedback. ]
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Lukas Bulwahn [Mon, 25 Jan 2021 07:41:05 +0000 (08:41 +0100)]
rcu-tasks: Rectify kernel-doc for struct rcu_tasks
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 <lukas.bulwahn@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Paul E. McKenney [Wed, 10 Feb 2021 21:25:58 +0000 (13:25 -0800)]
torture: Make jitter.sh handle large systems
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 subjected to jitter.sh
CPU-time perturbations. This commit therefore computes a given CPU's
cpumask using text manipulation rather than arithmetic shifts.
Reported-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Paul E. McKenney [Wed, 27 Jan 2021 21:57:16 +0000 (13:57 -0800)]
rcu: Make rcu_read_unlock_special() expedite strict grace periods
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 check of
this Kconfig option that causes rcu_read_unlock_special() to treat all
grace periods as expedited for CONFIG_RCU_STRICT_GRACE_PERIOD=y kernels.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Paul E. McKenney [Fri, 15 Jan 2021 21:30:38 +0000 (13:30 -0800)]
rcutorture: Fix testing of RCU priority boosting
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, these tests
will fail unless TIMER_SOFTIRQ runs at realtime priority, which does not
happen in current mainline. This commit therefore also refuses to test
RCU priority boosting except in kernels built with CONFIG_PREEMPT_RT=y.
While in the area, this commt adds some debug output at boost-fail time
that helps diagnose the cause of the failure, for example, failing to
run TIMER_SOFTIRQ at realtime priority.
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Scott Wood <swood@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Paul E. McKenney [Fri, 15 Jan 2021 00:11:04 +0000 (16:11 -0800)]
rcutorture: Make TREE03 use real-time tree.use_softirq setting
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.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Paul E. McKenney [Thu, 14 Jan 2021 18:39:31 +0000 (10:39 -0800)]
rcu: Expedite deboost in case of deferred quiescent state
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 disabled, the deboosting
will be delayed for some time. During this time, a low-priority process
might be incorrectly running at a high real-time priority level.
Fortunately, rcu_read_unlock_special() already provides mechanisms for
forcing a minimal deferral of quiescent states, at least for kernels
built with CONFIG_IRQ_WORK=y. These mechanisms are currently used
when expedited grace periods are pending that might be blocked by the
current task. This commit therefore causes those mechanisms to also be
used in cases where the current task has been or might soon be subjected
to RCU priority boosting. Note that this applies to all kernels built
with CONFIG_RCU_BOOST=y, regardless of whether or not they are also
built with CONFIG_PREEMPT_RT=y.
This approach assumes that kernels build for use with aggressive real-time
applications are built with CONFIG_IRQ_WORK=y. It is likely to be far
simpler to enable CONFIG_IRQ_WORK=y than to implement a fast-deboosting
scheme that works correctly in its absence.
While in the area, alphabetize the rcu_preempt_deferred_qs_handler()
function's local variables.
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Scott Wood <swood@redhat.com>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Frederic Weisbecker [Thu, 28 Jan 2021 17:12:13 +0000 (18:12 +0100)]
rcu/nocb: Rename nocb_gp_update_state to nocb_gp_update_state_deoffloading
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 of being de-offloaded.
Reported-by: Paul E. McKenney <paulmck@kernel.org>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: Neeraj Upadhyay <neeraju@codeaurora.org>
Cc: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Frederic Weisbecker [Thu, 28 Jan 2021 17:12:10 +0000 (18:12 +0100)]
rcu/nocb: Only (re-)initialize segcblist when needed on CPU up
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 non-offloaded CPU comes back online. In this case,
it is both necessary and permissible to initialize ->cblist.
Because either the CPU is currently running with interrupts
disabled (boot CPU) or is not yet running at all (other CPUs),
it is not necessary to acquire ->nocb_lock.
In this case, initialization is required.
2. Disabled and non-empty. This cannot occur, because early boot
call_rcu() invocations enable the callback list before enqueuing
their callback.
3. Enabled, whether empty or not. In this case, the callback
list has already been initialized. This case occurs when the
boot CPU has executed an early boot call_rcu() and also when
an offloaded CPU comes back online. In both cases, there is
no need to initialize the callback list: In the boot-CPU case,
the CPU has not (yet) gone offline, and in the offloaded case,
the rcuo kthreads are taking care of business.
Because it is not necessary to initialize the callback list,
it is also not necessary to acquire ->nocb_lock.
Therefore, checking if the segcblist is enabled suffices. This commit
therefore initializes the callback list at rcutree_prepare_cpu() time
only if that list is disabled.
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: Neeraj Upadhyay <neeraju@codeaurora.org>
Cc: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Frederic Weisbecker [Thu, 28 Jan 2021 17:12:12 +0000 (18:12 +0100)]
rcu/nocb: Avoid confusing double write of rdp->nocb_cb_sleep
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
locklessly. This commit therefore writes it only once, based on the
state after both callback invocation and checking.
Reported-by: Paul E. McKenney <paulmck@kernel.org>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: Neeraj Upadhyay <neeraju@codeaurora.org>
Cc: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Frederic Weisbecker [Thu, 28 Jan 2021 17:12:09 +0000 (18:12 +0100)]
rcu/nocb: Forbid NOCB toggling on offline CPUs
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 use a number of tricks
to permit offloading and deoffloading offline CPUs in certain cases, but
in practice it is far better to have the simple and deterministic rule
"Toggling the offload state of an offline CPU is forbidden".
For but one example, consider that an offloaded offline CPU might have
millions of callbacks queued. Best to just say "no".
This commit therefore forbids toggling of the offloaded state of
offline CPUs.
Reported-by: Paul E. McKenney <paulmck@kernel.org>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: Neeraj Upadhyay <neeraju@codeaurora.org>
Cc: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Frederic Weisbecker [Thu, 28 Jan 2021 17:12:08 +0000 (18:12 +0100)]
rcu/nocb: Comment the reason behind BH disablement on batch processing
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 Feng <boqun.feng@gmail.com>
Reported-by: Paul E. McKenney <paulmck@kernel.org>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: Neeraj Upadhyay <neeraju@codeaurora.org>
Cc: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Frederic Weisbecker [Thu, 12 Nov 2020 00:51:21 +0000 (01:51 +0100)]
rcu/nocb: Detect unsafe checks for offloaded rdp
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.
Local non-preemptible reads are also safe. NOCB kthreads and timers have
their own means of synchronization against the offloaded state updaters.
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: Neeraj Upadhyay <neeraju@codeaurora.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Paul E. McKenney [Tue, 8 Dec 2020 05:23:36 +0000 (21:23 -0800)]
rcutorture: Add crude tests for mem_dump_obj()
This commit adds a few crude tests for mem_dump_obj() to rcutorture
runs. Just to prevent bitrot, you understand!
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Paul E. McKenney [Thu, 7 Jan 2021 21:46:11 +0000 (13:46 -0800)]
mm: Don't build mm_dump_obj() on CONFIG_PRINTK=n kernels
The mem_dump_obj() functionality adds a few hundred bytes, which is a
small price to pay. Except on kernels built with CONFIG_PRINTK=n, in
which mem_dump_obj() messages will be suppressed. This commit therefore
makes mem_dump_obj() be a static inline empty function on kernels built
with CONFIG_PRINTK=n and excludes all of its support functions as well.
This avoids kernel bloat on systems that cannot use mem_dump_obj().
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: <linux-mm@kvack.org>
Suggested-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Uladzislau Rezki (Sony) [Wed, 17 Feb 2021 18:51:10 +0000 (19:51 +0100)]
rcuscale: Add kfree_rcu() single-argument scale test
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 kfree_rcu_test_double. If one
is set and the other not, only the corresponding variant
is tested, otherwise both are tested, with the variant to
be tested determined randomly on each invocation.
Both of these module parameters are initialized to false,
so setting either to true will test only that variant.
Suggested-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Uladzislau Rezki (Sony) [Fri, 29 Jan 2021 20:05:05 +0000 (21:05 +0100)]
kvfree_rcu: Use same set of GFP flags as does single-argument
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 rcuscale with below parameters:
../kvm.sh --torture rcuscale --allcpus --duration 10 --kconfig CONFIG_NR_CPUS=64 \
--bootargs "rcuscale.kfree_rcu_test=1 rcuscale.kfree_nthreads=16 rcuscale.holdoff=20 \
rcuscale.kfree_loops=10000 torture.disable_onoff_at_boot" --trust-make
<snip>
[ 12.054448] kworker/1:1H invoked oom-killer: gfp_mask=0x2cc0(GFP_KERNEL|__GFP_NOWARN), order=0, oom_score_adj=0
[ 12.055303] CPU: 1 PID: 377 Comm: kworker/1:1H Not tainted 5.11.0-rc3+ #510
[ 12.055416] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.12.0-1 04/01/2014
[ 12.056485] Workqueue: events_highpri fill_page_cache_func
[ 12.056485] Call Trace:
[ 12.056485] dump_stack+0x57/0x6a
[ 12.056485] dump_header+0x4c/0x30a
[ 12.056485] ? del_timer_sync+0x20/0x30
[ 12.056485] out_of_memory.cold.47+0xa/0x7e
[ 12.056485] __alloc_pages_slowpath.constprop.123+0x82f/0xc00
[ 12.056485] __alloc_pages_nodemask+0x289/0x2c0
[ 12.056485] __get_free_pages+0x8/0x30
[ 12.056485] fill_page_cache_func+0x39/0xb0
[ 12.056485] process_one_work+0x1ed/0x3b0
[ 12.056485] ? process_one_work+0x3b0/0x3b0
[ 12.060485] worker_thread+0x28/0x3c0
[ 12.060485] ? process_one_work+0x3b0/0x3b0
[ 12.060485] kthread+0x138/0x160
[ 12.060485] ? kthread_park+0x80/0x80
[ 12.060485] ret_from_fork+0x22/0x30
[ 12.062156] Mem-Info:
[ 12.062350] active_anon:0 inactive_anon:0 isolated_anon:0
[ 12.062350] active_file:0 inactive_file:0 isolated_file:0
[ 12.062350] unevictable:0 dirty:0 writeback:0
[ 12.062350] slab_reclaimable:2797 slab_unreclaimable:80920
[ 12.062350] mapped:1 shmem:2 pagetables:8 bounce:0
[ 12.062350] free:10488 free_pcp:1227 free_cma:0
...
[ 12.101610] Out of memory and no killable processes...
[ 12.102042] Kernel panic - not syncing: System is deadlocked on memory
[ 12.102583] CPU: 1 PID: 377 Comm: kworker/1:1H Not tainted 5.11.0-rc3+ #510
[ 12.102600] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.12.0-1 04/01/2014
<snip>
Because kvfree_rcu() has a fallback path, memory allocation failure is
not the end of the world. Furthermore, the added overhead of aggressive
GFP settings must be balanced against the overhead of the fallback path,
which is a cache miss for double-argument kvfree_rcu() and a call to
synchronize_rcu() for single-argument kvfree_rcu(). The current choice
of GFP_KERNEL|__GFP_NOWARN can result in longer latencies than a call
to synchronize_rcu(), so less-tenacious GFP flags would be helpful.
Here is the tradeoff that must be balanced:
a) Minimize use of the fallback path,
b) Avoid pushing the system into OOM,
c) Bound allocation latency to that of synchronize_rcu(), and
d) Leave the emergency reserves to use cases lacking fallbacks.
This commit therefore changes GFP flags from GFP_KERNEL|__GFP_NOWARN to
GFP_KERNEL|__GFP_NORETRY|__GFP_NOMEMALLOC|__GFP_NOWARN. This combination
leaves the emergency reserves alone and can initiate reclaim, but will
not invoke the OOM killer.
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Uladzislau Rezki (Sony) [Fri, 29 Jan 2021 16:16:03 +0000 (17:16 +0100)]
kvfree_rcu: Replace __GFP_RETRY_MAYFAIL by __GFP_NORETRY
__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, allowing the fallback to be taken as an alternative
to hard-OOMing the system.
There is a four-way tradeoff that must be balanced:
1) Minimize use of the fallback path;
2) Avoid full-up OOM;
3) Do a light-wait allocation request;
4) Avoid dipping into the emergency reserves.
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Paul E. McKenney [Wed, 20 Jan 2021 21:38:08 +0000 (13:38 -0800)]
kvfree_rcu: Make krc_this_cpu_unlock() use raw_spin_unlock_irqrestore()
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 raw_spin_unlock_irqrestore()
responds immediately to a reschedule request. In contrast,
local_irq_restore() does a scheduling-oblivious enabling of interrupts.
Reported-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Paul E. McKenney [Wed, 20 Jan 2021 16:21:47 +0000 (17:21 +0100)]
kvfree_rcu: Use __GFP_NOMEMALLOC for single-argument kvfree_rcu()
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 <mhocko@suse.com>
Suggested-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Uladzislau Rezki (Sony) [Wed, 20 Jan 2021 16:21:46 +0000 (17:21 +0100)]
kvfree_rcu: Directly allocate page for single-argument case
Single-argument kvfree_rcu() must be invoked from sleepable contexts,
so we can directly allocate pages. Furthermmore, the fallback in case
of page-allocation failure is the high-latency synchronize_rcu(), so it
makes sense to do these page allocations from the fastpath, and even to
permit limited sleeping within the allocator.
This commit therefore allocates if needed on the fastpath using
GFP_KERNEL|__GFP_RETRY_MAYFAIL. This also has the beneficial effect
of leaving kvfree_rcu()'s per-CPU caches to the double-argument variant
of kvfree_rcu(), 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) <urezki@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Mauro Carvalho Chehab [Thu, 14 Jan 2021 07:22:02 +0000 (08:22 +0100)]
rcu: Fix kfree_rcu() docbook errors
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: warning: Excess function parameter 'rhf' description in 'kfree_rcu'
This commit added some macro magic in order to call two different versions
of kfree_rcu(), the first having just one argument and the second having
two arguments. That makes it difficult to document the kfree_rcu() arguments
in the docboook header.
In order to make clearer that this macro accepts optional arguments,
this commit uses macro concatenation so that this macro changes from:
#define kfree_rcu kvfree_rcu
to:
#define kfree_rcu(ptr, rhf...) kvfree_rcu(ptr, ## rhf)
That not only helps kernel-doc understand the macro arguments, but also
provides a better C definition that makes clearer that the first argument
is mandatory and the second one is optional.
Fixes:
5130b8fd0690 ("rcu: Introduce kfree_rcu() single-argument macro")
Tested-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Akira Yokosawa [Fri, 15 Jan 2021 15:11:45 +0000 (00:11 +0900)]
rculist: Replace reference to atomic_ops.rst
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 loops.
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Akira Yokosawa <akiyks@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Zhouyi Zhou [Mon, 11 Jan 2021 01:08:59 +0000 (09:08 +0800)]
rcu: Remove spurious instrumentation_end() in rcu_nmi_enter()
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 marks
following trace_rcu_dyntick() as visited. This commit therefore removes
the spurious instrumentation_end().
Fixes:
04b25a495bd6 ("rcu: Mark rcu_nmi_enter() call to rcu_cleanup_after_idle() noinstr")
Reported-by Neeraj Upadhyay <neeraju@codeaurora.org>
Signed-off-by: Zhouyi Zhou <zhouzhouyi@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Neeraj Upadhyay [Mon, 11 Jan 2021 11:45:58 +0000 (17:15 +0530)]
rcu: Fix CPU-offline trace in rcutree_dying_cpu
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 best misleading.
This commit therefore switches these strings in order to correctly trace
whether the outgoing cpu blocks the current grace period.
Signed-off-by: Neeraj Upadhyay <neeraju@codeaurora.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Frederic Weisbecker [Wed, 6 Jan 2021 22:07:15 +0000 (23:07 +0100)]
rcu: Remove superfluous rdp fetch
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar<mingo@kernel.org>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Paul E. McKenney [Thu, 21 Jan 2021 23:56:53 +0000 (15:56 -0800)]
rcutorture: Use "all" and "N" in "nohz_full" and "rcu_nocbs"
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 <paul.gortmaker@windriver.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Paul Gortmaker [Sun, 21 Feb 2021 08:08:27 +0000 (03:08 -0500)]
rcu: deprecate "all" option to rcu_nocbs=
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 it. The support itself needs to remain for now, since we don't
know how many people out there are using it currently, but since it
is in an __init area anyway, it isn't worth losing sleep over.
Cc: Yury Norov <yury.norov@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Josh Triplett <josh@joshtriplett.org>
Acked-by: Yury Norov <yury.norov@gmail.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Paul Gortmaker [Sun, 21 Feb 2021 08:08:26 +0000 (03:08 -0500)]
lib: test_bitmap: add tests for "N" alias
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 <yury.norov@gmail.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Yury Norov <yury.norov@gmail.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Paul Gortmaker [Sun, 21 Feb 2021 08:08:25 +0000 (03:08 -0500)]
lib: bitmap: support "N" as an alias for size of bitmap
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 similarly configured cores to take on the real workload of
interest to the user.
So on machine A - with 32 cores, it could be 0-3 for "system" and then
4-31 being used in boot args like nohz_full=, or rcu_nocbs= as part of
setting up the worker pool of CPUs.
But then newer machine B is added, and it has 48 cores, and so while
the 0-3 part remains unchanged, the pool setup cpu list becomes 4-47.
Multiple deployment becomes easier when we can just simply replace 31
and 47 with "N" and let the system substitute in the actual number at
boot; a number that it knows better than we do.
Cc: Yury Norov <yury.norov@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Suggested-by: Yury Norov <yury.norov@gmail.com> # move it from CPU code
Acked-by: Yury Norov <yury.norov@gmail.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Paul Gortmaker [Sun, 21 Feb 2021 08:08:24 +0000 (03:08 -0500)]
lib: bitmap: move ERANGE check from set_region to check_region
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 <yury.norov@gmail.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Yury Norov <yury.norov@gmail.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Paul Gortmaker [Sun, 21 Feb 2021 08:08:23 +0000 (03:08 -0500)]
lib: bitmap: fold nbits into region struct
This will reduce parameter passing and enable using nbits as part
of future dynamic region parameter parsing.
Cc: Yury Norov <yury.norov@gmail.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Suggested-by: Yury Norov <yury.norov@gmail.com>
Acked-by: Yury Norov <yury.norov@gmail.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Paul Gortmaker [Sun, 21 Feb 2021 08:08:22 +0000 (03:08 -0500)]
lib: test_bitmap: add more start-end:offset/len tests
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 tests serve two purposes:
1) document what might seem odd but nonetheless valid input.
2) don't regress from what we currently accept as valid.
Cc: Yury Norov <yury.norov@gmail.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Yury Norov <yury.norov@gmail.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Paul Gortmaker [Sun, 21 Feb 2021 08:08:21 +0000 (03:08 -0500)]
lib: test_bitmap: add tests to trigger ERANGE case.
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 <yury.norov@gmail.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Yury Norov <yury.norov@gmail.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Paul Gortmaker [Sun, 21 Feb 2021 08:08:20 +0000 (03:08 -0500)]
lib: test_bitmap: clearly separate ERANGE from EINVAL tests.
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 to 32 bit so it is clear what they are meant to target.
Then we can add tests specific for ERANGE (no syntax errors, just
doing 32bit op on 8 bit width, plus a typical 9-on-8 fencepost error).
Cc: Yury Norov <yury.norov@gmail.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Yury Norov <yury.norov@gmail.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Linus Torvalds [Sat, 6 Mar 2021 01:33:41 +0000 (17:33 -0800)]
Linux 5.12-rc2
Linus Torvalds [Sat, 6 Mar 2021 01:27:59 +0000 (17:27 -0800)]
Merge tag 'for-linus' of git://git./linux/kernel/git/rdma/rdma
Pull rdma fixes from Jason Gunthorpe:
"Nothing special here, though Bob's regression fixes for rxe would have
made it before the rc cycle had there not been such strong winter
weather!
- Fix corner cases in the rxe reference counting cleanup that are
causing regressions in blktests for SRP
- Two kdoc fixes so W=1 is clean
- Missing error return in error unwind for mlx5
- Wrong lock type nesting in IB CM"
* tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma:
RDMA/rxe: Fix errant WARN_ONCE in rxe_completer()
RDMA/rxe: Fix extra deref in rxe_rcv_mcast_pkt()
RDMA/rxe: Fix missed IB reference counting in loopback
RDMA/uverbs: Fix kernel-doc warning of _uverbs_alloc
RDMA/mlx5: Set correct kernel-doc identifier
IB/mlx5: Add missing error code
RDMA/rxe: Fix missing kconfig dependency on CRYPTO
RDMA/cm: Fix IRQ restore in ib_send_cm_sidr_rep
Linus Torvalds [Sat, 6 Mar 2021 01:23:03 +0000 (17:23 -0800)]
Merge tag 'gcc-plugins-v5.12-rc2' of git://git./linux/kernel/git/kees/linux
Pull gcc-plugins fixes from Kees Cook:
"Tiny gcc-plugin fixes for v5.12-rc2. These issues are small but have
been reported a couple times now by static analyzers, so best to get
them fixed to reduce the noise. :)
- Fix coding style issues (Jason Yan)"
* tag 'gcc-plugins-v5.12-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
gcc-plugins: latent_entropy: remove unneeded semicolon
gcc-plugins: structleak: remove unneeded variable 'ret'
Linus Torvalds [Sat, 6 Mar 2021 01:21:25 +0000 (17:21 -0800)]
Merge tag 'pstore-v5.12-rc2' of git://git./linux/kernel/git/kees/linux
Pull pstore fixes from Kees Cook:
- Rate-limit ECC warnings (Dmitry Osipenko)
- Fix error path check for NULL (Tetsuo Handa)
* tag 'pstore-v5.12-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
pstore/ram: Rate-limit "uncorrectable error in header" message
pstore: Fix warning in pstore_kill_sb()
Linus Torvalds [Fri, 5 Mar 2021 21:25:23 +0000 (13:25 -0800)]
Merge tag 'for-5.12/dm-fixes' of git://git./linux/kernel/git/device-mapper/linux-dm
Pull device mapper fixes from Mike Snitzer:
"Fix DM verity target's optional Forward Error Correction (FEC) for
Reed-Solomon roots that are unaligned to block size"
* tag 'for-5.12/dm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
dm verity: fix FEC for RS roots unaligned to block size
dm bufio: subtract the number of initial sectors in dm_bufio_get_device_size
Linus Torvalds [Fri, 5 Mar 2021 20:59:37 +0000 (12:59 -0800)]
Merge tag 'block-5.12-2021-03-05' of git://git.kernel.dk/linux-block
Pull block fixes from Jens Axboe:
- NVMe fixes:
- more device quirks (Julian Einwag, Zoltán Böszörményi, Pascal
Terjan)
- fix a hwmon error return (Daniel Wagner)
- fix the keep alive timeout initialization (Martin George)
- ensure the model_number can't be changed on a used subsystem
(Max Gurtovoy)
- rsxx missing -EFAULT on copy_to_user() failure (Dan)
- rsxx remove unused linux.h include (Tian)
- kill unused RQF_SORTED (Jean)
- updated outdated BFQ comments (Joseph)
- revert work-around commit for bd_size_lock, since we removed the
offending user in this merge window (Damien)
* tag 'block-5.12-2021-03-05' of git://git.kernel.dk/linux-block:
nvmet: model_number must be immutable once set
nvme-fabrics: fix kato initialization
nvme-hwmon: Return error code when registration fails
nvme-pci: add quirks for Lexar 256GB SSD
nvme-pci: mark Kingston SKC2000 as not supporting the deepest power state
nvme-pci: mark Seagate Nytro XM1440 as QUIRK_NO_NS_DESC_LIST.
rsxx: Return -EFAULT if copy_to_user() fails
block/bfq: update comments and default value in docs for fifo_expire
rsxx: remove unused including <linux/version.h>
block: Drop leftover references to RQF_SORTED
block: revert "block: fix bd_size_lock use"
Linus Torvalds [Fri, 5 Mar 2021 20:44:43 +0000 (12:44 -0800)]
Merge tag 'io_uring-5.12-2021-03-05' of git://git.kernel.dk/linux-block
Pull io_uring fixes from Jens Axboe:
"A bit of a mix between fallout from the worker change, cleanups and
reductions now possible from that change, and fixes in general. In
detail:
- Fully serialize manager and worker creation, fixing races due to
that.
- Clean up some naming that had gone stale.
- SQPOLL fixes.
- Fix race condition around task_work rework that went into this
merge window.
- Implement unshare. Used for when the original task does unshare(2)
or setuid/seteuid and friends, drops the original workers and forks
new ones.
- Drop the only remaining piece of state shuffling we had left, which
was cred. Move it into issue instead, and we can drop all of that
code too.
- Kill f_op->flush() usage. That was such a nasty hack that we had
out of necessity, we no longer need it.
- Following from ->flush() removal, we can also drop various bits of
ctx state related to SQPOLL and cancelations.
- Fix an issue with IOPOLL retry, which originally was fallout from a
filemap change (removing iov_iter_revert()), but uncovered an issue
with iovec re-import too late.
- Fix an issue with system suspend.
- Use xchg() for fallback work, instead of cmpxchg().
- Properly destroy io-wq on exec.
- Add create_io_thread() core helper, and use that in io-wq and
io_uring. This allows us to remove various silly completion events
related to thread setup.
- A few error handling fixes.
This should be the grunt of fixes necessary for the new workers, next
week should be quieter. We've got a pending series from Pavel on
cancelations, and how tasks and rings are indexed. Outside of that,
should just be minor fixes. Even with these fixes, we're still killing
a net ~80 lines"
* tag 'io_uring-5.12-2021-03-05' of git://git.kernel.dk/linux-block: (41 commits)
io_uring: don't restrict issue_flags for io_openat
io_uring: make SQPOLL thread parking saner
io-wq: kill hashed waitqueue before manager exits
io_uring: clear IOCB_WAITQ for non -EIOCBQUEUED return
io_uring: don't keep looping for more events if we can't flush overflow
io_uring: move to using create_io_thread()
kernel: provide create_io_thread() helper
io_uring: reliably cancel linked timeouts
io_uring: cancel-match based on flags
io-wq: ensure all pending work is canceled on exit
io_uring: ensure that threads freeze on suspend
io_uring: remove extra in_idle wake up
io_uring: inline __io_queue_async_work()
io_uring: inline io_req_clean_work()
io_uring: choose right tctx->io_wq for try cancel
io_uring: fix -EAGAIN retry with IOPOLL
io-wq: fix error path leak of buffered write hash map
io_uring: remove sqo_task
io_uring: kill sqo_dead and sqo submission halting
io_uring: ignore double poll add on the same waitqueue head
...
Linus Torvalds [Fri, 5 Mar 2021 20:36:33 +0000 (12:36 -0800)]
Merge tag 'pm-5.12-rc2' of git://git./linux/kernel/git/rafael/linux-pm
Pull power management fixes from Rafael Wysocki:
"These fix the usage of device links in the runtime PM core code and
update the DTPM (Dynamic Thermal Power Management) feature added
recently.
Specifics:
- Make the runtime PM core code avoid attempting to suspend supplier
devices before updating the PM-runtime status of a consumer to
'suspended' (Rafael Wysocki).
- Fix DTPM (Dynamic Thermal Power Management) root node
initialization and label that feature as EXPERIMENTAL in Kconfig
(Daniel Lezcano)"
* tag 'pm-5.12-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
powercap/drivers/dtpm: Add the experimental label to the option description
powercap/drivers/dtpm: Fix root node initialization
PM: runtime: Update device status before letting suppliers suspend
Linus Torvalds [Fri, 5 Mar 2021 20:32:17 +0000 (12:32 -0800)]
Merge tag 'acpi-5.12-rc2' of git://git./linux/kernel/git/rafael/linux-pm
Pull ACPI fix from Rafael Wysocki:
"Make the empty stubs of some helper functions used when CONFIG_ACPI is
not set actually match those functions (Andy Shevchenko)"
* tag 'acpi-5.12-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
ACPI: bus: Constify is_acpi_node() and friends (part 2)
Linus Torvalds [Fri, 5 Mar 2021 20:26:24 +0000 (12:26 -0800)]
Merge tag 'iommu-fixes-v5.12-rc1' of git://git./linux/kernel/git/joro/iommu
Pull iommu fixes from Joerg Roedel:
- Fix a sleeping-while-atomic issue in the AMD IOMMU code
- Disable lazy IOTLB flush for untrusted devices in the Intel VT-d
driver
- Fix status code definitions for Intel VT-d
- Fix IO Page Fault issue in Tegra IOMMU driver
* tag 'iommu-fixes-v5.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu:
iommu/vt-d: Fix status code for Allocate/Free PASID command
iommu: Don't use lazy flush for untrusted device
iommu/tegra-smmu: Fix mc errors on tegra124-nyan
iommu/amd: Fix sleeping in atomic in increase_address_space()
Linus Torvalds [Fri, 5 Mar 2021 20:21:14 +0000 (12:21 -0800)]
Merge tag 'for-5.12-rc1-tag' of git://git./linux/kernel/git/kdave/linux
Pull btrfs fixes from David Sterba:
"More regression fixes and stabilization.
Regressions:
- zoned mode
- count zone sizes in wider int types
- fix space accounting for read-only block groups
- subpage: fix page tail zeroing
Fixes:
- fix spurious warning when remounting with free space tree
- fix warning when creating a directory with smack enabled
- ioctl checks for qgroup inheritance when creating a snapshot
- qgroup
- fix missing unlock on error path in zero range
- fix amount of released reservation on error
- fix flushing from unsafe context with open transaction,
potentially deadlocking
- minor build warning fixes"
* tag 'for-5.12-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
btrfs: zoned: do not account freed region of read-only block group as zone_unusable
btrfs: zoned: use sector_t for zone sectors
btrfs: subpage: fix the false data csum mismatch error
btrfs: fix warning when creating a directory with smack enabled
btrfs: don't flush from btrfs_delayed_inode_reserve_metadata
btrfs: export and rename qgroup_reserve_meta
btrfs: free correct amount of space in btrfs_delayed_inode_reserve_metadata
btrfs: fix spurious free_space_tree remount warning
btrfs: validate qgroup inherit for SNAP_CREATE_V2 ioctl
btrfs: unlock extents in btrfs_zero_range in case of quota reservation errors
btrfs: ref-verify: use 'inline void' keyword ordering
Linus Torvalds [Fri, 5 Mar 2021 20:12:28 +0000 (12:12 -0800)]
Merge tag 'devicetree-fixes-for-5.12-1' of git://git./linux/kernel/git/robh/linux
Pull devicetree fixes from Rob Herring:
- Another batch of graph and video-interfaces schema conversions
- Drop DT header symlink for dropped C6X arch
- Fix bcm2711-hdmi schema error
* tag 'devicetree-fixes-for-5.12-1' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux:
dt-bindings: media: Use graph and video-interfaces schemas, round 2
dts: drop dangling c6x symlink
dt-bindings: bcm2711-hdmi: Fix broken schema
Linus Torvalds [Fri, 5 Mar 2021 20:04:59 +0000 (12:04 -0800)]
Merge tag 'trace-v5.12-rc1' of git://git./linux/kernel/git/rostedt/linux-trace
Pull tracing fixes from Steven Rostedt:
"Functional fixes:
- Fix big endian conversion for arm64 in recordmcount processing
- Fix timestamp corruption in ring buffer on discarding events
- Fix memory leak in __create_synth_event()
- Skip selftests if tracing is disabled as it will cause them to
fail.
Non-functional fixes:
- Fix help text in Kconfig
- Remove duplicate prototype for trace_empty()
- Fix stale comment about the trace_event_call flags.
Self test update:
- Add more information to the validation output of when a corrupt
timestamp is found in the ring buffer, and also trigger a warning
to make sure that tests catch it"
* tag 'trace-v5.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
tracing: Fix comment about the trace_event_call flags
tracing: Skip selftests if tracing is disabled
tracing: Fix memory leak in __create_synth_event()
ring-buffer: Add a little more information and a WARN when time stamp going backwards is detected
ring-buffer: Force before_stamp and write_stamp to be different on discard
tracing: Fix help text of TRACEPOINT_BENCHMARK in Kconfig
tracing: Remove duplicate declaration from trace.h
ftrace: Have recordmcount use w8 to read relp->r_info in arm64_is_fake_mcount
Bob Pearson [Thu, 4 Mar 2021 19:20:49 +0000 (13:20 -0600)]
RDMA/rxe: Fix errant WARN_ONCE in rxe_completer()
In rxe_comp.c in rxe_completer() the function free_pkt() did not clear skb
which triggered a warning at 'done:' and could possibly at 'exit:'. The
WARN_ONCE() calls are not actually needed. The call to free_pkt() is
moved to the end to clearly show that all skbs are freed.
Fixes:
899aba891cab ("RDMA/rxe: Fix FIXME in rxe_udp_encap_recv()")
Link: https://lore.kernel.org/r/20210304192048.2958-1-rpearson@hpe.com
Signed-off-by: Bob Pearson <rpearsonhpe@gmail.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Bob Pearson [Thu, 4 Mar 2021 19:20:49 +0000 (13:20 -0600)]
RDMA/rxe: Fix extra deref in rxe_rcv_mcast_pkt()
rxe_rcv_mcast_pkt() dropped a reference to ib_device when no error
occurred causing an underflow on the reference counter. This code is
cleaned up to be clearer and easier to read.
Fixes:
899aba891cab ("RDMA/rxe: Fix FIXME in rxe_udp_encap_recv()")
Link: https://lore.kernel.org/r/20210304192048.2958-1-rpearson@hpe.com
Signed-off-by: Bob Pearson <rpearsonhpe@gmail.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Bob Pearson [Thu, 4 Mar 2021 19:20:49 +0000 (13:20 -0600)]
RDMA/rxe: Fix missed IB reference counting in loopback
When the noted patch below extending the reference taken by
rxe_get_dev_from_net() in rxe_udp_encap_recv() until each skb is freed it
was not matched by a reference in the loopback path resulting in
underflows.
Fixes:
899aba891cab ("RDMA/rxe: Fix FIXME in rxe_udp_encap_recv()")
Link: https://lore.kernel.org/r/20210304192048.2958-1-rpearson@hpe.com
Signed-off-by: Bob Pearson <rpearsonhpe@gmail.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Pavel Begunkov [Sun, 28 Feb 2021 22:35:14 +0000 (22:35 +0000)]
io_uring: don't restrict issue_flags for io_openat
45d189c606292 ("io_uring: replace force_nonblock with flags") did
something strange for io_openat() slicing all issue_flags but
IO_URING_F_NONBLOCK. Not a bug for now, but better to just forward the
flags.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Jens Axboe [Fri, 5 Mar 2021 16:13:07 +0000 (09:13 -0700)]
Merge tag 'nvme-5.12-2021-03-05' of git://git.infradead.org/nvme into block-5.12
Pull NVMe fixes from Christoph:
"nvme fixes for 5.12:
- more device quirks (Julian Einwag, Zoltán Böszörményi, Pascal Terjan)
- fix a hwmon error return (Daniel Wagner)
- fix the keep alive timeout initialization (Martin George)
- ensure the model_number can't be changed on a used subsystem
(Max Gurtovoy)"
* tag 'nvme-5.12-2021-03-05' of git://git.infradead.org/nvme:
nvmet: model_number must be immutable once set
nvme-fabrics: fix kato initialization
nvme-hwmon: Return error code when registration fails
nvme-pci: add quirks for Lexar 256GB SSD
nvme-pci: mark Kingston SKC2000 as not supporting the deepest power state
nvme-pci: mark Seagate Nytro XM1440 as QUIRK_NO_NS_DESC_LIST.
Jens Axboe [Fri, 5 Mar 2021 15:44:39 +0000 (08:44 -0700)]
io_uring: make SQPOLL thread parking saner
We have this weird true/false return from parking, and then some of the
callers decide to look at that. It can lead to unbalanced parks and
sqd locking. Have the callers check the thread status once it's parked.
We know we have the lock at that point, so it's either valid or it's NULL.
Fix race with parking on thread exit. We need to be careful here with
ordering of the sdq->lock and the IO_SQ_THREAD_SHOULD_PARK bit.
Rename sqd->completion to sqd->parked to reflect that this is the only
thing this completion event doesn.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Jens Axboe [Fri, 5 Mar 2021 15:14:08 +0000 (08:14 -0700)]
io-wq: kill hashed waitqueue before manager exits
If we race with shutting down the io-wq context and someone queueing
a hashed entry, then we can exit the manager with it armed. If it then
triggers after the manager has exited, we can have a use-after-free where
io_wqe_hash_wake() attempts to wake a now gone manager process.
Move the killing of the hashed write queue into the manager itself, so
that we know we've killed it before the task exits.
Fixes:
e941894eae31 ("io-wq: make buffered file write hashed work map per-ctx")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Jens Axboe [Fri, 5 Mar 2021 04:02:58 +0000 (21:02 -0700)]
io_uring: clear IOCB_WAITQ for non -EIOCBQUEUED return
The callback can only be armed, if we get -EIOCBQUEUED returned. It's
important that we clear the WAITQ bit for other cases, otherwise we can
queue for async retry and filemap will assume that we're armed and
return -EAGAIN instead of just blocking for the IO.
Cc: stable@vger.kernel.org # 5.9+
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Jens Axboe [Fri, 5 Mar 2021 00:15:48 +0000 (17:15 -0700)]
io_uring: don't keep looping for more events if we can't flush overflow
It doesn't make sense to wait for more events to come in, if we can't
even flush the overflow we already have to the ring. Return -EBUSY for
that condition, just like we do for attempts to submit with overflow
pending.
Cc: stable@vger.kernel.org # 5.11
Signed-off-by: Jens Axboe <axboe@kernel.dk>