| e9fe1827 | 24-Jan-2025 |
Tejun Heo <[email protected]> |
sched_ext: selftests/dsp_local_on: Fix sporadic failures
dsp_local_on has several incorrect assumptions, one of which is that
p->nr_cpus_allowed always tracks p->cpus_ptr. This is not true when a ta
sched_ext: selftests/dsp_local_on: Fix sporadic failures
dsp_local_on has several incorrect assumptions, one of which is that
p->nr_cpus_allowed always tracks p->cpus_ptr. This is not true when a task
is scheduled out while migration is disabled - p->cpus_ptr is temporarily
overridden to the previous CPU while p->nr_cpus_allowed remains unchanged.
This led to sporadic test faliures when dsp_local_on_dispatch() tries to put
a migration disabled task to a different CPU. Fix it by keeping the previous
CPU when migration is disabled.
There are SCX schedulers that make use of p->nr_cpus_allowed. They should
also implement explicit handling for p->migration_disabled.
Signed-off-by: Tejun Heo <[email protected]>
Reported-by: Ihor Solodrai <[email protected]>
Cc: Andrea Righi <[email protected]>
Cc: Changwoo Min <[email protected]>
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| ce2b93fc | 25-Dec-2024 |
Tejun Heo <[email protected]> |
sched_ext: Fix dsq_local_on selftest
The dsp_local_on selftest expects the scheduler to fail by trying to
schedule an e.g. CPU-affine task to the wrong CPU. However, this isn't
guaranteed to happen
sched_ext: Fix dsq_local_on selftest
The dsp_local_on selftest expects the scheduler to fail by trying to
schedule an e.g. CPU-affine task to the wrong CPU. However, this isn't
guaranteed to happen in the 1 second window that the test is running.
Besides, it's odd to have this particular exception path tested when there
are no other tests that verify that the interface is working at all - e.g.
the test would pass if dsp_local_on interface is completely broken and fails
on any attempt.
Flip the test so that it verifies that the feature works. While at it, fix a
typo in the info message.
Signed-off-by: Tejun Heo <[email protected]>
Reported-by: Ihor Solodrai <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Tejun Heo <[email protected]>
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| 895669fd | 25-Oct-2024 |
David Vernet <[email protected]> |
scx: Fix exit selftest to use custom DSQ
In commit 63fb3ec80516 ("sched_ext: Allow only user DSQs for
scx_bpf_consume(), scx_bpf_dsq_nr_queued() and bpf_iter_scx_dsq_new()"), we
updated the consume
scx: Fix exit selftest to use custom DSQ
In commit 63fb3ec80516 ("sched_ext: Allow only user DSQs for
scx_bpf_consume(), scx_bpf_dsq_nr_queued() and bpf_iter_scx_dsq_new()"), we
updated the consume path to only accept user DSQs, thus making it invalid
to consume SCX_DSQ_GLOBAL. This selftest was doing that, so let's create a
custom DSQ and use that instead. The test now passes:
[root@virtme-ng sched_ext]# ./runner -t exit
===== START =====
TEST: exit
DESCRIPTION: Verify we can cleanly exit a scheduler in multiple places
OUTPUT:
[ 12.387229] sched_ext: BPF scheduler "exit" enabled
[ 12.406064] sched_ext: BPF scheduler "exit" disabled (unregistered from BPF)
[ 12.453325] sched_ext: BPF scheduler "exit" enabled
[ 12.474064] sched_ext: BPF scheduler "exit" disabled (unregistered from BPF)
[ 12.515241] sched_ext: BPF scheduler "exit" enabled
[ 12.532064] sched_ext: BPF scheduler "exit" disabled (unregistered from BPF)
[ 12.592063] sched_ext: BPF scheduler "exit" disabled (unregistered from BPF)
[ 12.654063] sched_ext: BPF scheduler "exit" disabled (unregistered from BPF)
[ 12.715062] sched_ext: BPF scheduler "exit" disabled (unregistered from BPF)
ok 1 exit #
===== END =====
Signed-off-by: David Vernet <[email protected]>
Signed-off-by: Tejun Heo <[email protected]>
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| 9b3c11a8 | 21-Oct-2024 |
Ihor Solodrai <[email protected]> |
selftests/sched_ext: add order-only dependency of runner.o on BPFOBJ
The runner.o may start building before libbpf headers are installed,
and as a result build fails. This happened a couple of times
selftests/sched_ext: add order-only dependency of runner.o on BPFOBJ
The runner.o may start building before libbpf headers are installed,
and as a result build fails. This happened a couple of times on
libbpf/ci test jobs:
* https://github.com/libbpf/ci/actions/runs/11447667257/job/31849533100
* https://github.com/theihor/libbpf-ci/actions/runs/11445162764/job/31841649552
Headers are installed in a recipe for $(BPFOBJ) target, and adding an
order-only dependency should ensure this doesn't happen.
Signed-off-by: Ihor Solodrai <[email protected]>
Signed-off-by: Tejun Heo <[email protected]>
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| 81951366 | 04-Sep-2024 |
Tejun Heo <[email protected]> |
sched_ext: Add cgroup support
Add sched_ext_ops operations to init/exit cgroups, and track task migrations
and config changes. A BPF scheduler may not implement or implement only
subset of cgroup fe
sched_ext: Add cgroup support
Add sched_ext_ops operations to init/exit cgroups, and track task migrations
and config changes. A BPF scheduler may not implement or implement only
subset of cgroup features. The implemented features can be indicated using
%SCX_OPS_HAS_CGOUP_* flags. If cgroup configuration makes use of features
that are not implemented, a warning is triggered.
While a BPF scheduler is being enabled and disabled, relevant cgroup
operations are locked out using scx_cgroup_rwsem. This avoids situations
like task prep taking place while the task is being moved across cgroups,
making things easier for BPF schedulers.
v7: - cgroup interface file visibility toggling is dropped in favor just
warning messages. Dynamically changing interface visiblity caused more
confusion than helping.
v6: - Updated to reflect the removal of SCX_KF_SLEEPABLE.
- Updated to use CONFIG_GROUP_SCHED_WEIGHT and fixes for
!CONFIG_FAIR_GROUP_SCHED && CONFIG_EXT_GROUP_SCHED.
v5: - Flipped the locking order between scx_cgroup_rwsem and
cpus_read_lock() to avoid locking order conflict w/ cpuset. Better
documentation around locking.
- sched_move_task() takes an early exit if the source and destination
are identical. This triggered the warning in scx_cgroup_can_attach()
as it left p->scx.cgrp_moving_from uncleared. Updated the cgroup
migration path so that ops.cgroup_prep_move() is skipped for identity
migrations so that its invocations always match ops.cgroup_move()
one-to-one.
v4: - Example schedulers moved into their own patches.
- Fix build failure when !CONFIG_CGROUP_SCHED, reported by Andrea Righi.
v3: - Make scx_example_pair switch all tasks by default.
- Convert to BPF inline iterators.
- scx_bpf_task_cgroup() is added to determine the current cgroup from
CPU controller's POV. This allows BPF schedulers to accurately track
CPU cgroup membership.
- scx_example_flatcg added. This demonstrates flattened hierarchy
implementation of CPU cgroup control and shows significant performance
improvement when cgroups which are nested multiple levels are under
competition.
v2: - Build fixes for different CONFIG combinations.
Signed-off-by: Tejun Heo <[email protected]>
Reviewed-by: David Vernet <[email protected]>
Acked-by: Josh Don <[email protected]>
Acked-by: Hao Luo <[email protected]>
Acked-by: Barret Rhoden <[email protected]>
Reported-by: kernel test robot <[email protected]>
Cc: Andrea Righi <[email protected]>
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