| Age | Commit message (Collapse) | Author |
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The queued remote wakeup mechanism has turned out to be suboptimal for RT
enabled kernels. The maximum latencies go up by a factor of > 5x in certain
scenarious.
This is caused by either long wake lists or by a large number of TTWU IPIs
which are processed back to back.
Disable it for RT.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20210928122411.482262764@linutronix.de
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Batched task migrations are a source for large latencies as they keep the
scheduler from running while processing the migrations.
Limit the batch size to 8 instead of 32 when running on a RT enabled
kernel.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20210928122411.425097596@linutronix.de
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mmdrop() is invoked from finish_task_switch() by the incoming task to drop
the mm which was handed over by the previous task. mmdrop() can be quite
expensive which prevents an incoming real-time task from getting useful
work done.
Provide mmdrop_sched() which maps to mmdrop() on !RT kernels. On RT kernels
it delagates the eventually required invocation of __mmdrop() to RCU.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20210928122411.648582026@linutronix.de
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Make cookie functions static as these are no longer invoked directly
by other code.
No functional change intended.
Signed-off-by: Shaokun Zhang <zhangshaokun@hisilicon.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20210922085735.52812-1-zhangshaokun@hisilicon.com
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When deciding to pull tasks in ASYM_PACKING, it is necessary not only to
check for the idle state of the destination CPU, dst_cpu, but also of
its SMT siblings.
If dst_cpu is idle but its SMT siblings are busy, performance suffers
if it pulls tasks from a medium priority CPU that does not have SMT
siblings.
Implement asym_smt_can_pull_tasks() to inspect the state of the SMT
siblings of both dst_cpu and the CPUs in the candidate busiest group.
Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Reviewed-by: Len Brown <len.brown@intel.com>
Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>
Link: https://lkml.kernel.org/r/20210911011819.12184-7-ricardo.neri-calderon@linux.intel.com
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Create a separate function, sched_asym(). A subsequent changeset will
introduce logic to deal with SMT in conjunction with asmymmetric
packing. Such logic will need the statistics of the scheduling
group provided as argument. Update them before calling sched_asym().
Co-developed-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Reviewed-by: Len Brown <len.brown@intel.com>
Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>
Link: https://lkml.kernel.org/r/20210911011819.12184-6-ricardo.neri-calderon@linux.intel.com
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Before deciding to pull tasks when using asymmetric packing of tasks,
on some architectures (e.g., x86) it is necessary to know not only the
state of dst_cpu but also of its SMT siblings. The decision to classify
a candidate busiest group as group_asym_packing is done in
update_sg_lb_stats(). Give this function access to the scheduling domain
statistics, which contains the statistics of the local group.
Originally-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Reviewed-by: Len Brown <len.brown@intel.com>
Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>
Link: https://lkml.kernel.org/r/20210911011819.12184-5-ricardo.neri-calderon@linux.intel.com
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sched_asmy_prefer() always returns false when called on the local group. By
checking local_group, we can avoid additional checks and invoking
sched_asmy_prefer() when it is not needed. No functional changes are
introduced.
Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Reviewed-by: Len Brown <len.brown@intel.com>
Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>
Link: https://lkml.kernel.org/r/20210911011819.12184-4-ricardo.neri-calderon@linux.intel.com
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There exist situations in which the load balance needs to know the
properties of the CPUs in a scheduling group. When using asymmetric
packing, for instance, the load balancer needs to know not only the
state of dst_cpu but also of its SMT siblings, if any.
Use the flags of the child scheduling domains to initialize scheduling
group flags. This will reflect the properties of the CPUs in the
group.
A subsequent changeset will make use of these new flags. No functional
changes are introduced.
Originally-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Reviewed-by: Len Brown <len.brown@intel.com>
Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>
Link: https://lkml.kernel.org/r/20210911011819.12184-3-ricardo.neri-calderon@linux.intel.com
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When scheduling, it is better to prefer a separate physical core rather
than the SMT sibling of a high priority core. The existing formula to
compute priorities takes such fact in consideration. There may exist,
however, combinations of priorities (i.e., maximum frequencies) in which
the priority of high-numbered SMT siblings of high-priority cores collides
with the priority of low-numbered SMT siblings of low-priority cores.
Consider for instance an SMT2 system with CPUs [0, 1] with priority 60 and
[2, 3] with priority 30(CPUs in brackets are SMT siblings. In such a case,
the resulting priorities would be [120, 60], [60, 30]. Thus, to ensure
that CPU2 has higher priority than CPU1, divide the raw priority by the
squared SMT iterator. The resulting priorities are [120, 30]. [60, 15].
Originally-by: Len Brown <len.brown@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20210911011819.12184-2-ricardo.neri-calderon@linux.intel.com
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With enabled threaded interrupts the nouveau driver reported the
following:
| Chain exists of:
| &mm->mmap_lock#2 --> &device->mutex --> &cpuset_rwsem
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| Possible unsafe locking scenario:
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| CPU0 CPU1
| ---- ----
| lock(&cpuset_rwsem);
| lock(&device->mutex);
| lock(&cpuset_rwsem);
| lock(&mm->mmap_lock#2);
The device->mutex is nvkm_device::mutex.
Unblocking the lockchain at `cpuset_rwsem' is probably the easiest
thing to do. Move the priority reset to the start of the newly
created thread.
Fixes: 710da3c8ea7df ("sched/core: Prevent race condition between cpuset and __sched_setscheduler()")
Reported-by: Mike Galbraith <efault@gmx.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/a23a826af7c108ea5651e73b8fbae5e653f16e86.camel@gmx.de
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Currently the boot defined preempt behaviour (aka dynamic preempt)
selects full preemption by default when the "preempt=" boot parameter
is omitted. However distros may rather want to default to either
no preemption or voluntary preemption.
To provide with this flexibility, make dynamic preemption a visible
Kconfig option and adapt the preemption behaviour selected by the user
to either static or dynamic preemption.
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20210914103134.11309-1-frederic@kernel.org
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These is no caller in tree since commit
523e979d3164 ("sched/core: Use PELT for scale_rt_capacity()")
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20210914095244.52780-1-yuehaibing@huawei.com
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After we make the struct sched_statistics and the helpers of it
independent of fair sched class, we can easily use the schedstats
facility for deadline sched class.
The schedstat usage in DL sched class is similar with fair sched class,
for example,
fair deadline
enqueue update_stats_enqueue_fair update_stats_enqueue_dl
dequeue update_stats_dequeue_fair update_stats_dequeue_dl
put_prev_task update_stats_wait_start update_stats_wait_start_dl
set_next_task update_stats_wait_end update_stats_wait_end_dl
The user can get the schedstats information in the same way in fair sched
class. For example,
fair deadline
/proc/[pid]/sched /proc/[pid]/sched
The output of a deadline task's schedstats as follows,
$ cat /proc/69662/sched
...
se.sum_exec_runtime : 3067.696449
se.nr_migrations : 0
sum_sleep_runtime : 720144.029661
sum_block_runtime : 0.547853
wait_start : 0.000000
sleep_start : 14131540.828955
block_start : 0.000000
sleep_max : 2999.974045
block_max : 0.283637
exec_max : 1.000269
slice_max : 0.000000
wait_max : 0.002217
wait_sum : 0.762179
wait_count : 733
iowait_sum : 0.547853
iowait_count : 3
nr_migrations_cold : 0
nr_failed_migrations_affine : 0
nr_failed_migrations_running : 0
nr_failed_migrations_hot : 0
nr_forced_migrations : 0
nr_wakeups : 246
nr_wakeups_sync : 2
nr_wakeups_migrate : 0
nr_wakeups_local : 244
nr_wakeups_remote : 2
nr_wakeups_affine : 0
nr_wakeups_affine_attempts : 0
nr_wakeups_passive : 0
nr_wakeups_idle : 0
...
The sched:sched_stat_{wait, sleep, iowait, blocked} tracepoints can
be used to trace deadlline tasks as well.
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20210905143547.4668-9-laoar.shao@gmail.com
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The runtime of a DL task has already been there, so we only need to
add a tracepoint.
One difference between fair task and DL task is that there is no vruntime
in dl task. To reuse the sched_stat_runtime tracepoint, '0' is passed as
vruntime for DL task.
The output of this tracepoint for DL task as follows,
top-36462 [047] d.h. 6083.452103: sched_stat_runtime: comm=top pid=36462 runtime=409898 [ns] vruntime=0 [ns]
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20210905143547.4668-8-laoar.shao@gmail.com
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We want to measure the latency of RT tasks in our production
environment with schedstats facility, but currently schedstats is only
supported for fair sched class. This patch enable it for RT sched class
as well.
After we make the struct sched_statistics and the helpers of it
independent of fair sched class, we can easily use the schedstats
facility for RT sched class.
The schedstat usage in RT sched class is similar with fair sched class,
for example,
fair RT
enqueue update_stats_enqueue_fair update_stats_enqueue_rt
dequeue update_stats_dequeue_fair update_stats_dequeue_rt
put_prev_task update_stats_wait_start update_stats_wait_start_rt
set_next_task update_stats_wait_end update_stats_wait_end_rt
The user can get the schedstats information in the same way in fair sched
class. For example,
fair RT
/proc/[pid]/sched /proc/[pid]/sched
schedstats is not supported for RT group.
The output of a RT task's schedstats as follows,
$ cat /proc/10349/sched
...
sum_sleep_runtime : 972.434535
sum_block_runtime : 960.433522
wait_start : 188510.871584
sleep_start : 0.000000
block_start : 0.000000
sleep_max : 12.001013
block_max : 952.660622
exec_max : 0.049629
slice_max : 0.000000
wait_max : 0.018538
wait_sum : 0.424340
wait_count : 49
iowait_sum : 956.495640
iowait_count : 24
nr_migrations_cold : 0
nr_failed_migrations_affine : 0
nr_failed_migrations_running : 0
nr_failed_migrations_hot : 0
nr_forced_migrations : 0
nr_wakeups : 49
nr_wakeups_sync : 0
nr_wakeups_migrate : 0
nr_wakeups_local : 49
nr_wakeups_remote : 0
nr_wakeups_affine : 0
nr_wakeups_affine_attempts : 0
nr_wakeups_passive : 0
nr_wakeups_idle : 0
...
The sched:sched_stat_{wait, sleep, iowait, blocked} tracepoints can
be used to trace RT tasks as well. The output of these tracepoints for a
RT tasks as follows,
- runtime
stress-10352 [004] d.h. 1035.382286: sched_stat_runtime: comm=stress pid=10352 runtime=995769 [ns] vruntime=0 [ns]
[vruntime=0 means it is a RT task]
- wait
<idle>-0 [004] dN.. 1227.688544: sched_stat_wait: comm=stress pid=10352 delay=46849882 [ns]
- blocked
kworker/4:1-465 [004] dN.. 1585.676371: sched_stat_blocked: comm=stress pid=17194 delay=189963 [ns]
- iowait
kworker/4:1-465 [004] dN.. 1585.675330: sched_stat_iowait: comm=stress pid=17189 delay=182848 [ns]
- sleep
sleep-18194 [023] dN.. 1780.891840: sched_stat_sleep: comm=sleep.sh pid=17767 delay=1001160770 [ns]
sleep-18196 [023] dN.. 1781.893208: sched_stat_sleep: comm=sleep.sh pid=17767 delay=1001161970 [ns]
sleep-18197 [023] dN.. 1782.894544: sched_stat_sleep: comm=sleep.sh pid=17767 delay=1001128840 [ns]
[ In sleep.sh, it sleeps 1 sec each time. ]
[lkp@intel.com: reported build failure in earlier version]
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20210905143547.4668-7-laoar.shao@gmail.com
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The runtime of a RT task has already been there, so we only need to
add a tracepoint.
One difference between fair task and RT task is that there is no vruntime
in RT task. To reuse the sched_stat_runtime tracepoint, '0' is passed as
vruntime for RT task.
The output of this tracepoint for RT task as follows,
stress-9748 [039] d.h. 113.519352: sched_stat_runtime: comm=stress pid=9748 runtime=997573 [ns] vruntime=0 [ns]
stress-9748 [039] d.h. 113.520352: sched_stat_runtime: comm=stress pid=9748 runtime=997627 [ns] vruntime=0 [ns]
stress-9748 [039] d.h. 113.521352: sched_stat_runtime: comm=stress pid=9748 runtime=998203 [ns] vruntime=0 [ns]
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20210905143547.4668-6-laoar.shao@gmail.com
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Currently in schedstats we have sum_sleep_runtime and iowait_sum, but
there's no metric to show how long the task is in D state. Once a task in
D state, it means the task is blocked in the kernel, for example the
task may be waiting for a mutex. The D state is more frequent than
iowait, and it is more critital than S state. So it is worth to add a
metric to measure it.
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20210905143547.4668-5-laoar.shao@gmail.com
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The original prototype of the schedstats helpers are
update_stats_wait_*(struct cfs_rq *cfs_rq, struct sched_entity *se)
The cfs_rq in these helpers is used to get the rq_clock, and the se is
used to get the struct sched_statistics and the struct task_struct. In
order to make these helpers available by all sched classes, we can pass
the rq, sched_statistics and task_struct directly.
Then the new helpers are
update_stats_wait_*(struct rq *rq, struct task_struct *p,
struct sched_statistics *stats)
which are independent of fair sched class.
To avoid vmlinux growing too large or introducing ovehead when
!schedstat_enabled(), some new helpers after schedstat_enabled() are also
introduced, Suggested by Mel. These helpers are in sched/stats.c,
__update_stats_wait_*(struct rq *rq, struct task_struct *p,
struct sched_statistics *stats)
The size of vmlinux as follows,
Before After
Size of vmlinux 826308552 826304640
The size is a litte smaller as some functions are not inlined again after
the change.
I also compared the sched performance with 'perf bench sched pipe',
suggested by Mel. The result as followsi (in usecs/op),
Before After
kernel.sched_schedstats=0 5.2~5.4 5.2~5.4
kernel.sched_schedstats=1 5.3~5.5 5.3~5.5
[These data is a little difference with the prev version, that is
because my old test machine is destroyed so I have to use a new
different test machine.]
Almost no difference.
No functional change.
[lkp@intel.com: reported build failure in prev version]
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Mel Gorman <mgorman@suse.de>
Link: https://lore.kernel.org/r/20210905143547.4668-4-laoar.shao@gmail.com
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If we want to use the schedstats facility to trace other sched classes, we
should make it independent of fair sched class. The struct sched_statistics
is the schedular statistics of a task_struct or a task_group. So we can
move it into struct task_struct and struct task_group to achieve the goal.
After the patch, schestats are orgnized as follows,
struct task_struct {
...
struct sched_entity se;
struct sched_rt_entity rt;
struct sched_dl_entity dl;
...
struct sched_statistics stats;
...
};
Regarding the task group, schedstats is only supported for fair group
sched, and a new struct sched_entity_stats is introduced, suggested by
Peter -
struct sched_entity_stats {
struct sched_entity se;
struct sched_statistics stats;
} __no_randomize_layout;
Then with the se in a task_group, we can easily get the stats.
The sched_statistics members may be frequently modified when schedstats is
enabled, in order to avoid impacting on random data which may in the same
cacheline with them, the struct sched_statistics is defined as cacheline
aligned.
As this patch changes the core struct of scheduler, so I verified the
performance it may impact on the scheduler with 'perf bench sched
pipe', suggested by Mel. Below is the result, in which all the values
are in usecs/op.
Before After
kernel.sched_schedstats=0 5.2~5.4 5.2~5.4
kernel.sched_schedstats=1 5.3~5.5 5.3~5.5
[These data is a little difference with the earlier version, that is
because my old test machine is destroyed so I have to use a new
different test machine.]
Almost no impact on the sched performance.
No functional change.
[lkp@intel.com: reported build failure in earlier version]
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Mel Gorman <mgorman@suse.de>
Link: https://lore.kernel.org/r/20210905143547.4668-3-laoar.shao@gmail.com
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schedstat_enabled() has been already checked, so we can use
__schedstat_set() directly.
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Mel Gorman <mgorman@suse.de>
Link: https://lore.kernel.org/r/20210905143547.4668-2-laoar.shao@gmail.com
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Previously, 'make -C sched run_tests' will block forever when it occurs
something wrong where the *selftests framework* is waiting for its child
processes to exit.
[root@iaas-rpma sched]# ./cs_prctl_test
## Create a thread/process/process group hiearchy
Not a core sched system
tid=74985, / tgid=74985 / pgid=74985: ffffffffffffffff
Not a core sched system
tid=74986, / tgid=74986 / pgid=74985: ffffffffffffffff
Not a core sched system
tid=74988, / tgid=74986 / pgid=74985: ffffffffffffffff
Not a core sched system
tid=74989, / tgid=74986 / pgid=74985: ffffffffffffffff
Not a core sched system
tid=74990, / tgid=74986 / pgid=74985: ffffffffffffffff
Not a core sched system
tid=74987, / tgid=74987 / pgid=74985: ffffffffffffffff
Not a core sched system
tid=74991, / tgid=74987 / pgid=74985: ffffffffffffffff
Not a core sched system
tid=74992, / tgid=74987 / pgid=74985: ffffffffffffffff
Not a core sched system
tid=74993, / tgid=74987 / pgid=74985: ffffffffffffffff
Not a core sched system
(268) FAILED: get_cs_cookie(0) == 0
## Set a cookie on entire process group
-1 = prctl(62, 1, 0, 2, 0)
core_sched create failed -- PGID: Invalid argument
(cs_prctl_test.c:272) -
[root@iaas-rpma sched]# ps
PID TTY TIME CMD
4605 pts/2 00:00:00 bash
74986 pts/2 00:00:00 cs_prctl_test
74987 pts/2 00:00:00 cs_prctl_test
74999 pts/2 00:00:00 ps
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Li Zhijian <lizhijian@cn.fujitsu.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Chris Hyser <chris.hyser@oracle.com>
Link: https://lore.kernel.org/r/20210902024333.75983-1-lizhijian@cn.fujitsu.com
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Basic description of usage and effect for CFS Bandwidth Control Burst.
Co-developed-by: Shanpei Chen <shanpeic@linux.alibaba.com>
Signed-off-by: Shanpei Chen <shanpeic@linux.alibaba.com>
Co-developed-by: Tianchen Ding <dtcccc@linux.alibaba.com>
Signed-off-by: Tianchen Ding <dtcccc@linux.alibaba.com>
Signed-off-by: Huaixin Chang <changhuaixin@linux.alibaba.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20210830032215.16302-3-changhuaixin@linux.alibaba.com
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Two new statistics are introduced to show the internal of burst feature
and explain why burst helps or not.
nr_bursts: number of periods bandwidth burst occurs
burst_time: cumulative wall-time (in nanoseconds) that any cpus has
used above quota in respective periods
Co-developed-by: Shanpei Chen <shanpeic@linux.alibaba.com>
Signed-off-by: Shanpei Chen <shanpeic@linux.alibaba.com>
Co-developed-by: Tianchen Ding <dtcccc@linux.alibaba.com>
Signed-off-by: Tianchen Ding <dtcccc@linux.alibaba.com>
Signed-off-by: Huaixin Chang <changhuaixin@linux.alibaba.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20210830032215.16302-2-changhuaixin@linux.alibaba.com
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Give reduced sleeper credit to SCHED_IDLE entities. As a result, woken
SCHED_IDLE entities will take longer to preempt normal entities.
The benefit of this change is to make it less likely that a newly woken
SCHED_IDLE entity will preempt a short-running normal entity before it
blocks.
We still give a small sleeper credit to SCHED_IDLE entities, so that
idle<->idle competition retains some fairness.
Example: With HZ=1000, spawned four threads affined to one cpu, one of
which was set to SCHED_IDLE. Without this patch, wakeup latency for the
SCHED_IDLE thread was ~1-2ms, with the patch the wakeup latency was
~5ms.
Signed-off-by: Josh Don <joshdon@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>
Reviewed-by: Jiang Biao <benbjiang@tencent.com>
Link: https://lore.kernel.org/r/20210820010403.946838-5-joshdon@google.com
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Use a small, non-scaled min granularity for SCHED_IDLE entities, when
competing with normal entities. This reduces the latency of getting
a normal entity back on cpu, at the expense of increased context
switch frequency of SCHED_IDLE entities.
The benefit of this change is to reduce the round-robin latency for
normal entities when competing with a SCHED_IDLE entity.
Example: on a machine with HZ=1000, spawned two threads, one of which is
SCHED_IDLE, and affined to one cpu. Without this patch, the SCHED_IDLE
thread runs for 4ms then waits for 1.4s. With this patch, it runs for
1ms and waits 340ms (as it round-robins with the other thread).
Signed-off-by: Josh Don <joshdon@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>
Link: https://lore.kernel.org/r/20210820010403.946838-4-joshdon@google.com
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Adds cfs_rq->idle_nr_running, which accounts the number of idle entities
directly enqueued on the cfs_rq.
Signed-off-by: Josh Don <joshdon@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>
Link: https://lore.kernel.org/r/20210820010403.946838-3-joshdon@google.com
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/proc/uptime reports idle time by reading the CPUTIME_IDLE field from
the per-cpu kcpustats. However, on NO_HZ systems, idle time is not
continually updated on idle cpus, leading this value to appear
incorrectly small.
/proc/stat performs an accounting update when reading idle time; we
can use the same approach for uptime.
With this patch, /proc/stat and /proc/uptime now agree on idle time.
Additionally, the following shows idle time tick up consistently on an
idle machine:
(while true; do cat /proc/uptime; sleep 1; done) | awk '{print $2-prev; prev=$2}'
Reported-by: Luigi Rizzo <lrizzo@google.com>
Signed-off-by: Josh Don <joshdon@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://lkml.kernel.org/r/20210827165438.3280779-1-joshdon@google.com
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Tao suggested a two-pass task selection to avoid the retry loop.
Not only does it avoid the retry loop, it results in *much* simpler
code.
This also fixes an issue spotted by Josh Don where, for SMT3+, we can
forget to update max on the first pass and get to do an extra round.
Suggested-by: Tao Zhou <tao.zhou@linux.dev>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Josh Don <joshdon@google.com>
Reviewed-by: Vineeth Pillai (Microsoft) <vineethrp@gmail.com>
Link: https://lkml.kernel.org/r/YSS9+k1teA9oPEKl@hirez.programming.kicks-ass.net
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With PREEMPT_RT enabled all hrtimers callbacks will be invoked in
softirq mode unless they are explicitly marked as HRTIMER_MODE_HARD.
During boot kthread_bind() is used for the creation of per-CPU threads
and then hangs in wait_task_inactive() if the ksoftirqd is not
yet up and running.
The hang disappeared since commit
26c7295be0c5e ("kthread: Do not preempt current task if it is going to call schedule()")
but enabling function trace on boot reliably leads to the freeze on boot
behaviour again.
The timer in wait_task_inactive() can not be directly used by a user
interface to abuse it and create a mass wake up of several tasks at the
same time leading to long sections with disabled interrupts.
Therefore it is safe to make the timer HRTIMER_MODE_REL_HARD.
Switch the timer to HRTIMER_MODE_REL_HARD.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20210826170408.vm7rlj7odslshwch@linutronix.de
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Consider a system with some NOHZ-idle CPUs, such that
nohz.idle_cpus_mask = S
nohz.next_balance = T
When a new CPU k goes NOHZ idle (nohz_balance_enter_idle()), we end up
with:
nohz.idle_cpus_mask = S \U {k}
nohz.next_balance = T
Note that the nohz.next_balance hasn't changed - it won't be updated until
a NOHZ balance is triggered. This is problematic if the newly NOHZ idle CPU
has an earlier rq.next_balance than the other NOHZ idle CPUs, IOW if:
cpu_rq(k).next_balance < nohz.next_balance
In such scenarios, the existing nohz.next_balance will prevent any NOHZ
balance from happening, which itself will prevent nohz.next_balance from
being updated to this new cpu_rq(k).next_balance. Unnecessary load balance
delays of over 12ms caused by this were observed on an arm64 RB5 board.
Use the new nohz.needs_update flag to mark the presence of newly-idle CPUs
that need their rq->next_balance to be collated into
nohz.next_balance. Trigger a NOHZ_NEXT_KICK when the flag is set.
Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>
Link: https://lkml.kernel.org/r/20210823111700.2842997-3-valentin.schneider@arm.com
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A following patch will trigger NOHZ idle balances as a means to update
nohz.next_balance. Vincent noted that blocked load updates can have
non-negligible overhead, which should be avoided if the intent is to only
update nohz.next_balance.
Add a new NOHZ balance kick flag, NOHZ_NEXT_KICK. Gate NOHZ blocked load
update by the presence of NOHZ_STATS_KICK - currently all NOHZ balance
kicks will have the NOHZ_STATS_KICK flag set, so no change in behaviour is
expected.
Suggested-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>
Link: https://lkml.kernel.org/r/20210823111700.2842997-2-valentin.schneider@arm.com
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fastrpc driver is using find_vma() without any protection, as a
result we see below warning due to recent patch 5b78ed24e8ec
("mm/pagemap: add mmap_assert_locked() annotations to find_vma*()")
which added mmap_assert_locked() in find_vma() function.
This bug went un-noticed in previous versions. Fix this issue by adding
required protection while calling find_vma().
CPU: 0 PID: 209746 Comm: benchmark_model Not tainted 5.15.0-rc2-00445-ge14fe2bf817a-dirty #969
Hardware name: Qualcomm Technologies, Inc. Robotics RB5 (DT)
pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : find_vma+0x64/0xd0
lr : find_vma+0x60/0xd0
sp : ffff8000158ebc40
...
Call trace:
find_vma+0x64/0xd0
fastrpc_internal_invoke+0x570/0xda8
fastrpc_device_ioctl+0x3e0/0x928
__arm64_sys_ioctl+0xac/0xf0
invoke_syscall+0x44/0x100
el0_svc_common.constprop.3+0x70/0xf8
do_el0_svc+0x24/0x88
el0_svc+0x3c/0x138
el0t_64_sync_handler+0x90/0xb8
el0t_64_sync+0x180/0x184
Fixes: 80f3afd72bd4 ("misc: fastrpc: consider address offset before sending to DSP")
Cc: stable@vger.kernel.org
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20210922154326.8927-1-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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clang-14 complains about an unusual way of converting a pointer to
an integer:
drivers/misc/cb710/sgbuf2.c:50:15: error: performing pointer subtraction with a null pointer has undefined behavior [-Werror,-Wnull-pointer-subtraction]
return ((ptr - NULL) & 3) != 0;
Replace this with a normal cast to uintptr_t.
Fixes: 5f5bac8272be ("mmc: Driver for CB710/720 memory card reader (MMC part)")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20210927121408.939246-1-arnd@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Currently autoloading for SPI devices does not use the DT ID table, it uses
SPI modalises. Supporting OF modalises is going to be difficult if not
impractical, an attempt was made but has been reverted, so ensure that
module autoloading works for this driver by adding a SPI ID table entry
for the device name part of the compatible - currently only the full
compatible is listed which isn't very idiomatic and won't match the
modalias that is generated.
Fixes: 96c8395e2166 ("spi: Revert modalias changes")
Cc: stable <stable@vger.kernel.org>
Tested-by: Martyn Welch <martyn.welch@collabora.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20210923194609.52647-1-broonie@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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gcc warns that accessing a pointer based on a numeric constant may
be an offset into a NULL pointer, and would therefore has zero
accessible bytes:
arch/arm/common/sharpsl_param.c: In function ‘sharpsl_save_param’:
arch/arm/common/sharpsl_param.c:43:9: error: ‘memcpy’ reading 64 bytes from a region of size 0 [-Werror=stringop-overread]
43 | memcpy(&sharpsl_param, param_start(PARAM_BASE), sizeof(struct sharpsl_param_info));
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In this particular case, the warning is bogus since this is the actual
pointer, not an offset on a NULL pointer. Add a local variable to shut
up the warning and hope it doesn't come back.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Daniel Mack <daniel@zonque.org>
Cc: Daniel Mack <daniel@zonque.org>
Cc: Haojian Zhuang <haojian.zhuang@gmail.com>
Cc: Robert Jarzmik <robert.jarzmik@free.fr>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Linus Walleij <linus.walleij@linaro.org>
Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99578
Link: https://lore.kernel.org/r/20210927145332.2784005-1-arnd@kernel.org'
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
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git://git.kernel.org/pub/scm/linux/kernel/git/shawnguo/linux into arm/fixes
i.MX fixes for 5.15:
- Revert cc8870bf4c3a to fix the regression on i.MX6 that suspend
support becomes broken.
- Add `qca,clk-out-frequency` property to fix Ethernet support on
imx6qdl-pico board.
- Re-enable FB support in imx_v6_v7_defconfig. It gets lost due to
f611b1e7624c ("drm: Avoid circular dependencies for CONFIG_FB").
- Fix LP5562 LED support on imx6dl-yapp4 board.
- Add missing pinctrl-names for panel on M53Menlo board.
- Fix USB host power regulator polarity on M53Menlo board.
* tag 'imx-fixes-5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/shawnguo/linux:
ARM: imx_v6_v7_defconfig: enable fb
ARM: dts: imx6qdl-pico: Fix Ethernet support
ARM: dts: imx: Fix USB host power regulator polarity on M53Menlo
ARM: dts: imx: Add missing pinctrl-names for panel on M53Menlo
Revert "ARM: imx6q: drop of_platform_default_populate() from init_machine"
ARM: dts: imx6dl-yapp4: Fix lp5562 LED driver probe
Link: https://lore.kernel.org/r/20210923063356.GK13480@dragon
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
|
|
The framebuffer is gone on the D-Link DIR-685, restore it.
Fixes: f611b1e7624c ("drm: Avoid circular dependencies for CONFIG_FB")
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Cc: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20210922200933.1825752-1-linus.walleij@linaro.org'
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
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This can cause a randconfig warning without the 'inline' flag
that every other platform uses:
In file included from arch/arm/boot/compressed/misc.c:29:
arch/arm/mach-dove/include/mach/uncompress.h:14:13: error: 'putc' defined but not used [-Werror=unused-function]
14 | static void putc(const char c)
| ^~~~
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://lore.kernel.org/r/20210927095343.1015422-1-arnd@kernel.org'
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
|
|
Commit 38225f2ef2f4 ("ARM/omap1: switch to use dma_direct_set_offset for
lbus DMA offsets") removed a lot of mach/memory.h, but left the USB
offset handling split into arch/arm/mach-omap1/usb.c and
drivers/usb/host/ohci-omap.c.
This can cause a randconfig build warning that now fails the build
with -Werror:
arch/arm/mach-omap1/usb.c:561:30: error: 'omap_1510_usb_ohci_nb' defined but not used [-Werror=unused-variable]
561 | static struct notifier_block omap_1510_usb_ohci_nb = {
| ^~~~~~~~~~~~~~~~~~~~~
Move it all into the platform file to get rid of the final
location that relies on mach/memory.h.
Acked-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Acked-by: Tony Lindgren <tony@atomide.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20210927144118.2464881-1-arnd@kernel.org'
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
|
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Make code more readable.
Don't try to read zero bytes.
Add warning when size of exteneded attribute exceeds limit.
Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>
|
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We always need to lock now, because locks became smaller
(see d562e901f25d
"fs/ntfs3: Move ni_lock_dir and ni_unlock into ntfs_create_inode").
Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>
|
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We don't need to maintain ntfs_posix_acl_release.
Reviewed-by: Kari Argillander <kari.argillander@gmail.com>
Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>
|
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git://git.kernel.org/pub/scm/linux/kernel/git/qcom/linux into arm/fixes
Qualcomm driver fixes for v5.15
This restricts the QCOM_SCM driver to depend on ARCH_QCOM, to reduce
it's presence after becoming a loadable module.
It then fixes a regression in the mdt_loader, where firmware with the
hash segment marked as PT_LOAD would no longer be accepted, preventing
several MSM8974 and SDM660 devices from loading remoteproc firmware.
Lastly it corrects the drvdata associated with the socinfo device during
probe, to match that expected by the remove function.
* tag 'qcom-drivers-fixes-for-5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/qcom/linux:
firmware: qcom_scm: QCOM_SCM should depend on ARCH_QCOM
soc: qcom: mdt_loader: Drop PT_LOAD check on hash segment
soc: qcom: socinfo: Fixed argument passed to platform_set_data()
Link: https://lore.kernel.org/r/20210930025456.1035-1-bjorn.andersson@linaro.org
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
|
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git://git.kernel.org/pub/scm/linux/kernel/git/qcom/linux into arm/fixes
Qualcomm ARM64 DTS fixes for 5.15
This starts by reverting the SC7280 CPUfreq update, which was merged
before concensus about the associated drivers changes was reached.
It then moves the reserved-memory changes done to get IPA working on the
Lenovo Yoga C630 into the Yoga specific DTS, as changing the memory map
on the platform level did break a couple of the other boards.
It fixes the HDMI audio on Trogdor and add missing Aggre2 NOC qos clocks
on SDM6{30,36,60} which prevented some boards from booting.
Lastly it enables the PON module on SM8250/QRB5165, as the lack thereof
is blocking automated testing in LKFT.
* tag 'qcom-arm64-fixes-for-5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/qcom/linux:
arm64: dts: qcom: sdm630: Add missing a2noc qos clocks
arm64: dts: qcom: qrb5165-rb5: enabled pwrkey and resin nodes
arm64: dts: qcom: pm8150: specify reboot mode magics
arm64: dts: qcom: pm8150: use qcom,pm8998-pon binding
arm64: dts: qcom: sc7180-trogdor: Fix lpass dai link for HDMI
arm64: dts: qcom: sdm850-yoga: Reshuffle IPA memory mappings
Revert "arm64: dts: qcom: sc7280: Fixup the cpufreq node"
Link: https://lore.kernel.org/r/20210930025509.1091-1-bjorn.andersson@linaro.org
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
|
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git://git.kernel.org/pub/scm/linux/kernel/git/sudeep.holla/linux into arm/fixes
Juno/Vexpress fixes for v5.15
Bunch of DTS fixes to resolve addressing issues with some of the device
nodes, dropping unused/undocumented properties in various nodes, and
aligning node names with dtschema.
* tag 'juno-fixes-5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/sudeep.holla/linux:
arm: dts: vexpress: Fix motherboard bus 'interrupt-map'
arm: dts: vexpress: Fix addressing issues with 'motherboard-bus' nodes
arm: dts: vexpress-v2p-ca9: Fix the SMB unit-address
arm: dts: vexpress: Drop unused properties from motherboard node
arm64: dts: arm: drop unused interrupt-names in MHU
ARM: dts: arm: align watchdog and mmc node names with dtschema
arm64: dts: arm: align watchdog and mmc node names with dtschema
arm64: dts: fvp: Remove panel timings
Link: https://lore.kernel.org/r/20210927105249.3583380-1-sudeep.holla@arm.com
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/qcom/linux into arm/fixes
Qualcomm DTS fixes for v5.15
This corrects the use of depricated chipid and clock names, for which
support was finally dropped from the driver. It also ensures that the
DSI PLL is fed by the correct clock, now that it's being migrated to not
rely on global clock names.
* tag 'qcom-dts-fixes-for-5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/qcom/linux:
ARM: dts: qcom: apq8064: update Adreno clock names
ARM: dts: qcom: apq8064: Use 27MHz PXO clock as DSI PLL reference
ARM: dts: qcom: apq8064: use compatible which contains chipid
Link: https://lore.kernel.org/r/20210930025526.1146-1-bjorn.andersson@linaro.org
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/at91/linux into arm/fixes
AT91 fixes #2 for 5.15:
- More fixes for AT91 platform power management code related to the
introduction of sama7g5:
- management of DDR3L regulator rails for sama7g5ek
- loading of TLB on different cores
- PIO controller slew-rate settings for sama7g5ek: be aligned with
datasheet requirements.
* tag 'at91-fixes-5.15-2' of git://git.kernel.org/pub/scm/linux/kernel/git/at91/linux:
ARM: dts: at91: sama7g5ek: to not touch slew-rate for SDMMC pins
ARM: dts: at91: sama7g5ek: use proper slew-rate settings for GMACs
ARM: at91: pm: preload base address of controllers in tlb
ARM: at91: pm: group constants and addresses loading
ARM: dts: at91: sama7g5ek: add suspend voltage for ddr3l rail
Link: https://lore.kernel.org/r/20211004114344.19304-1-nicolas.ferre@microchip.com
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
|
|
Add Vignesh to TI K3 platform maintainership. We will rotate roles for
each kernel version to help spread the work load a little better.
Signed-off-by: Nishanth Menon <nm@ti.com>
Link: https://lore.kernel.org/r/20210915121308.26795-1-nm@ti.com'
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
|
|
git://git.linaro.org/people/jens.wiklander/linux-tee into arm/fixes
Fix OP-TEE shm_pool lint warning
* tag 'optee-fix-for-v5.15' of git://git.linaro.org/people/jens.wiklander/linux-tee:
tee/optee/shm_pool: fix application of sizeof to pointer
Link: https://lore.kernel.org/r/20210915113813.GA509196@jade
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
|
