[ Upstream commit c73801ae4f22b390228ebf471d55668e824198b6 ]
On no-MMU, all futexes are treated as private because there is no need
to map a virtual address to physical to match the futex across
processes. This doesn't quite work though, because private futexes
include the current process's mm_struct as part of their key. This makes
it impossible for one process to wake up a shared futex being waited on
in another process.
Fix this bug by excluding the mm_struct from the key. With
a single address space, the futex address is already a unique key.
Fixes: 784bdf3bb694 ("futex: Assume all mappings are private on !MMU systems")
Signed-off-by: Ben Wolsieffer <ben.wolsieffer@hefring.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Darren Hart <dvhart@infradead.org>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: André Almeida <andrealmeid@igalia.com>
Link: https://lore.kernel.org/r/20231019204548.1236437-2-ben.wolsieffer@hefring.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit e0f831836cead677fb07d54bd6bf499df35640c2 upstream.
Fix the following kernel-doc warnings:
kernel/trace/trace_kprobe.c:1029: warning: Excess function parameter 'args' description in '__kprobe_event_gen_cmd_start'
kernel/trace/trace_kprobe.c:1097: warning: Excess function parameter 'args' description in '__kprobe_event_add_fields'
Refer to the usage of variable length arguments elsewhere in the kernel
code, "@..." is the proper way to express it in the description.
Link: https://lore.kernel.org/all/20231027041315.2613166-1-yujie.liu@intel.com/
Fixes: 2a588dd1d5d6 ("tracing: Add kprobe event command generation functions")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202310190437.paI6LYJF-lkp@intel.com/
Signed-off-by: Yujie Liu <yujie.liu@intel.com>
Reviewed-by: Mukesh Ojha <quic_mojha@quicinc.com>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This is a simple IRQ balancer that polls every X number of milliseconds and
moves IRQs from the most interrupt-heavy CPU to the least interrupt-heavy
CPUs until the heaviest CPU is no longer the heaviest. IRQs are only moved
from one source CPU to any number of destination CPUs per balance run.
Balancing is skipped if the gap between the most interrupt-heavy CPU and
the least interrupt-heavy CPU is below the configured threshold of
interrupts.
The heaviest IRQs are targeted for migration in order to reduce the number
of IRQs to migrate. If moving an IRQ would reduce overall balance, then it
won't be migrated.
The most interrupt-heavy CPU is calculated by scaling the number of new
interrupts on that CPU to the CPU's current capacity. This way, interrupt
heaviness takes into account factors such as thermal pressure and time
spent processing interrupts rather than just the sheer number of them. This
also makes SBalance aware of CPU asymmetry, where different CPUs can have
different performance capacities and be proportionally balanced.
Signed-off-by: Sultan Alsawaf <sultan@kerneltoast.com>
Allow drivers to wait with a custom task state specified by exposing the
raw wait_for_common*() functions. This allows code to wait for completions
that are invariant with respect to CPU performance *without* contributing
to load avg, without requiring the wait to be interruptible.
Signed-off-by: Sultan Alsawaf <sultan@kerneltoast.com>
fsck.f2fs forces a filesystem fix on boot if it detects that the current
kernel version differs from the one saved in the superblock, which results in
fsck blocking boot for a long time (~35 seconds). This commit provides a
way to report a constant fake kernel version to fsck to avoid triggering
the version check, which is useful if you boot new kernel builds
frequently.
Signed-off-by: Danny Lin <danny@kdrag0n.dev>
Signed-off-by: UtsavBalar1231 <utsavbalar1231@gmail.com>
There is extensive spam in dmesg because of userspace.
This kills all "init", "healthd", "logd" messages in kernel logs and makes them
more readable.
Extracted from 59f163ac76.
Signed-off-by: idkwhoiam322 <idkwhoiam322@raphielgang.org>
Signed-off-by: prorooter007 <shreyashwasnik112@gmail.com>
Signed-off-by: celtare21 <celtare21@gmail.com>
If the last CPU frequency selected isn't set before a new CPU frequency
selection arrives, then use the new selection immediately to avoid using a
stale frequency choice. This improves both performance and energy by more
closely tracking the scheduler's latest decisions.
Signed-off-by: Sultan Alsawaf <sultan@kerneltoast.com>
[Flopster101: Adapted to Exynos energy_aware governor]
Signed-off-by: Nahuel Gómez <nahuelgomez329@gmail.com>
The schedutil governor reduces frequencies too fast in some
situations which cases undesirable performance drops to
appear.
To address that issue, make schedutil reduce the frequency slower by
setting it to the average of the value chosen during the previous
iteration of governor computations and the new one coming from its
frequency selection formula.
Link: https://bugzilla.kernel.org/show_bug.cgi?id=194963
Reported-by: John <john.ettedgui@gmail.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Cykeek <Cykeek@proton.me>
Signed-off-by: negrroo <mohammedaelnaggar1@gmail.com>
Signed-off-by: priiii1808 <priyanshusinghal0818@gmail.com>
[Flopster101: Adapted to Exynos energy_aware governor]
Signed-off-by: Nahuel Gómez <nahuelgomez329@gmail.com>
This is empirically observed to yield good performance with reduced power
consumption via having the down rate limit configured to be 2x longer than
the up rate limit. This reduces bouncing between CPU frequencies by
stalling down-clocking, which not only improves performance, but also
counter-intuitively improves power consumption.
The short up/down rate limits also provide improved interactivity and
real-time response.
Signed-off-by: Sultan Alsawaf <sultan@kerneltoast.com>
[Flopster101: Adapted to Exynos energy_aware governor]
Signed-off-by: Nahuel Gómez <nahuelgomez329@gmail.com>
The msm_irqbalance service in userspace constantly migrates IRQs between
CPUs according to its whims, which is not desired. All of the IRQs have
a sane affinity (CPU0 if unimportant, CPU4-7 otherwise), so prevent
userspace from tampering with that.
Signed-off-by: Sultan Alsawaf <sultanxda@gmail.com>
(cherry picked from commit 6cedf3c9b1f8c962d19ce4151ca5caaff69e3c6a)
(cherry picked from commit 8fc0013ba4094fd8fe95fb0d23af0936347060f4)
This patch fixes the latency_sensitive flag for all cpuset cgroups, and
the value present in the uclamp.latency_sensitive node directly
corresponds to the task_group's latency_sensitive value.
Prior to this patch, this was not the case. The
uclamp_latency_sensitive() function applied values only to the cpu
cgroup subsys instead of the required cpuset cgroup subsys, as a
result of which the latency_sensitive value remained zero for all
taskgroups irrespective of its setting.
Also, fix a situation where latency_sensitive is enabled for the
cpuset's root cgroup, in which case all tasks will have their value
as 1, which in turn will enable prefer_idle for all tasks. This is
undesired and may cause high battery drain.
Earlier commits in this series allow battery-powered systems to build
their kernels with the default-disabled CONFIG_RCU_LAZY=y Kconfig option.
This Kconfig option causes call_rcu() to delay its callbacks in order
to batch them. This means that a given RCU grace period covers more
callbacks, thus reducing the number of grace periods, in turn reducing
the amount of energy consumed, which increases battery lifetime which
can be a very good thing. This is not a subtle effect: In some important
use cases, the battery lifetime is increased by more than 10%.
This CONFIG_RCU_LAZY=y option is available only for CPUs that offload
callbacks, for example, CPUs mentioned in the rcu_nocbs kernel boot
parameter passed to kernels built with CONFIG_RCU_NOCB_CPU=y.
Delaying callbacks is normally not a problem because most callbacks do
nothing but free memory. If the system is short on memory, a shrinker
will kick all currently queued lazy callbacks out of their laziness,
thus freeing their memory in short order. Similarly, the rcu_barrier()
function, which blocks until all currently queued callbacks are invoked,
will also kick lazy callbacks, thus enabling rcu_barrier() to complete
in a timely manner.
However, there are some cases where laziness is not a good option.
For example, synchronize_rcu() invokes call_rcu(), and blocks until
the newly queued callback is invoked. It would not be a good for
synchronize_rcu() to block for ten seconds, even on an idle system.
Therefore, synchronize_rcu() invokes call_rcu_flush() instead of
call_rcu(). The arrival of a non-lazy call_rcu_flush() callback on a
given CPU kicks any lazy callbacks that might be already queued on that
CPU. After all, if there is going to be a grace period, all callbacks
might as well get full benefit from it.
Yes, this could be done the other way around by creating a
call_rcu_lazy(), but earlier experience with this approach and
feedback at the 2022 Linux Plumbers Conference shifted the approach
to call_rcu() being lazy with call_rcu_flush() for the few places
where laziness is inappropriate.
And another call_rcu() instance that cannot be lazy is the one
in queue_rcu_work(), given that callers to queue_rcu_work() are
not necessarily OK with long delays.
Therefore, make queue_rcu_work() use call_rcu_flush() in order to revert
to the old behavior.
Signed-off-by: Uladzislau Rezki <urezki@gmail.com>
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Simultaneously improves interactivity and power efficiency
[Flopster101: This also invalidates any value set by RCU_BOOST_DELAY.]
Signed-off-by: Nahuel Gómez <nahuelgomez329@gmail.com>
commit 32671e3799ca2e4590773fd0e63aaa4229e50c06 upstream.
Because group consistency is non-atomic between parent (filedesc) and children
(inherited) events, it is possible for PERF_FORMAT_GROUP read() to try and sum
non-matching counter groups -- with non-sensical results.
Add group_generation to distinguish the case where a parent group removes and
adds an event and thus has the same number, but a different configuration of
events as inherited groups.
This became a problem when commit fa8c269353d5 ("perf/core: Invert
perf_read_group() loops") flipped the order of child_list and sibling_list.
Previously it would iterate the group (sibling_list) first, and for each
sibling traverse the child_list. In this order, only the group composition of
the parent is relevant. By flipping the order the group composition of the
child (inherited) events becomes an issue and the mis-match in group
composition becomes evident.
That said; even prior to this commit, while reading of a group that is not
equally inherited was not broken, it still made no sense.
(Ab)use ECHILD as error return to indicate issues with child process group
composition.
Fixes: fa8c269353d5 ("perf/core: Invert perf_read_group() loops")
Reported-by: Budimir Markovic <markovicbudimir@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20231018115654.GK33217@noisy.programming.kicks-ass.net
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 23cce5f25491968b23fb9c399bbfb25f13870cd9 ]
When kernel is compiled without preemption, the eval_map_work_func()
(which calls trace_event_eval_update()) will not be preempted up to its
complete execution. This can actually cause a problem since if another
CPU call stop_machine(), the call will have to wait for the
eval_map_work_func() function to finish executing in the workqueue
before being able to be scheduled. This problem was observe on a SMP
system at boot time, when the CPU calling the initcalls executed
clocksource_done_booting() which in the end calls stop_machine(). We
observed a 1 second delay because one CPU was executing
eval_map_work_func() and was not preempted by the stop_machine() task.
Adding a call to cond_resched() in trace_event_eval_update() allows
other tasks to be executed and thus continue working asynchronously
like before without blocking any pending task at boot time.
Link: https://lore.kernel.org/linux-trace-kernel/20230929191637.416931-1-cleger@rivosinc.com
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Clément Léger <cleger@rivosinc.com>
Tested-by: Atish Patra <atishp@rivosinc.com>
Reviewed-by: Atish Patra <atishp@rivosinc.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 1ca0b605150501b7dc59f3016271da4eb3e96fce upstream.
One PID may appear multiple times in a preloaded pidlist.
(Possibly due to PID recycling but we have reports of the same
task_struct appearing with different PIDs, thus possibly involving
transfer of PID via de_thread().)
Because v1 seq_file iterator uses PIDs as position, it leads to
a message:
> seq_file: buggy .next function kernfs_seq_next did not update position index
Conservative and quick fix consists of removing duplicates from `tasks`
file (as opposed to removing pidlists altogether). It doesn't affect
correctness (it's sufficient to show a PID once), performance impact
would be hidden by unconditional sorting of the pidlist already in place
(asymptotically).
Link: https://lore.kernel.org/r/20230823174804.23632-1-mkoutny@suse.com/
Suggested-by: Firo Yang <firo.yang@suse.com>
Signed-off-by: Michal Koutný <mkoutny@suse.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit ca10d851b9ad0338c19e8e3089e24d565ebfffd7 ]
Commit 5c0338c68706 ("workqueue: restore WQ_UNBOUND/max_active==1
to be ordered") enabled implicit ordered attribute to be added to
WQ_UNBOUND workqueues with max_active of 1. This prevented the changing
of attributes to these workqueues leading to fix commit 0a94efb5acbb
("workqueue: implicit ordered attribute should be overridable").
However, workqueue_apply_unbound_cpumask() was not updated at that time.
So sysfs changes to wq_unbound_cpumask has no effect on WQ_UNBOUND
workqueues with implicit ordered attribute. Since not all WQ_UNBOUND
workqueues are visible on sysfs, we are not able to make all the
necessary cpumask changes even if we iterates all the workqueue cpumasks
in sysfs and changing them one by one.
Fix this problem by applying the corresponding change made
to apply_workqueue_attrs_locked() in the fix commit to
workqueue_apply_unbound_cpumask().
Fixes: 5c0338c68706 ("workqueue: restore WQ_UNBOUND/max_active==1 to be ordered")
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Userspace reads /proc/config.gz and spits out an error message after boot
finishes when it doesn't like the kernel's configuration. In order to
preserve our freedom to customize the kernel however we'd like, show
userspace the stock kirin config so that it never complains about our
kernel configuration.
