kernel/linux.git/tools/sched_ext, branch v6.13.2

sched_ext: fix application of sizeof to pointer

2024-12-04T19:47:39+00:00

sizeof when applied to a pointer typed expression gives the size of the pointer. The proper fix in this particular case is to code sizeof(*cpuset) instead of sizeof(cpuset). This issue was detected with the help of Coccinelle. Fixes: 22a920209ab6 ("sched_ext: Implement tickless support") Signed-off-by: guanjing Acked-by: Andrea Righi Signed-off-by: Tejun Heo

sched_ext: Add __weak to fix the build errors

2024-12-03T20:27:26+00:00

commit 5cbb302880f5 ("sched_ext: Rename scx_bpf_dispatch[_vtime]_from_dsq*() -> scx_bpf_dsq_move[_vtime]*()") introduced several new functions which caused compilation errors when compiled with clang. Let's fix this by adding __weak markers. Signed-off-by: Honglei Wang Signed-off-by: Tejun Heo Fixes: 5cbb302880f5 ("sched_ext: Rename scx_bpf_dispatch[_vtime]_from_dsq*() -> scx_bpf_dsq_move[_vtime]*()") Acked-by: Andrii Nakryiko

sched_ext: Rename scx_bpf_dispatch[_vtime]_from_dsq() -> scx_bpf_dsq_move[_vtime]()

2024-11-11T17:06:16+00:00

In sched_ext API, a repeatedly reported pain point is the overuse of the verb "dispatch" and confusion around "consume": - ops.dispatch() - scx_bpf_dispatch[_vtime]() - scx_bpf_consume() - scx_bpf_dispatch[_vtime]_from_dsq*() This overloading of the term is historical. Originally, there were only built-in DSQs and moving a task into a DSQ always dispatched it for execution. Using the verb "dispatch" for the kfuncs to move tasks into these DSQs made sense. Later, user DSQs were added and scx_bpf_dispatch[_vtime]() updated to be able to insert tasks into any DSQ. The only allowed DSQ to DSQ transfer was from a non-local DSQ to a local DSQ and this operation was named "consume". This was already confusing as a task could be dispatched to a user DSQ from ops.enqueue() and then the DSQ would have to be consumed in ops.dispatch(). Later addition of scx_bpf_dispatch_from_dsq*() made the confusion even worse as "dispatch" in this context meant moving a task to an arbitrary DSQ from a user DSQ. Clean up the API with the following renames: 1. scx_bpf_dispatch[_vtime]() -> scx_bpf_dsq_insert[_vtime]() 2. scx_bpf_consume() -> scx_bpf_dsq_move_to_local() 3. scx_bpf_dispatch[_vtime]_from_dsq*() -> scx_bpf_dsq_move[_vtime]*() This patch performs the third set of renames. Compatibility is maintained by: - The previous kfunc names are still provided by the kernel so that old binaries can run. Kernel generates a warning when the old names are used. - compat.bpf.h provides wrappers for the new names which automatically fall back to the old names when running on older kernels. They also trigger build error if old names are used for new builds. - scx_bpf_dispatch[_vtime]_from_dsq*() were already wrapped in __COMPAT macros as they were introduced during v6.12 cycle. Wrap new API in __COMPAT macros too and trigger build errors on both __COMPAT prefixed and naked usages of the old names. The compat features will be dropped after v6.15. Signed-off-by: Tejun Heo Acked-by: Andrea Righi Acked-by: Changwoo Min Acked-by: Johannes Bechberger Acked-by: Giovanni Gherdovich Cc: Dan Schatzberg Cc: Ming Yang

sched_ext: Rename scx_bpf_consume() to scx_bpf_dsq_move_to_local()

2024-11-11T17:06:16+00:00

In sched_ext API, a repeatedly reported pain point is the overuse of the verb "dispatch" and confusion around "consume": - ops.dispatch() - scx_bpf_dispatch[_vtime]() - scx_bpf_consume() - scx_bpf_dispatch[_vtime]_from_dsq*() This overloading of the term is historical. Originally, there were only built-in DSQs and moving a task into a DSQ always dispatched it for execution. Using the verb "dispatch" for the kfuncs to move tasks into these DSQs made sense. Later, user DSQs were added and scx_bpf_dispatch[_vtime]() updated to be able to insert tasks into any DSQ. The only allowed DSQ to DSQ transfer was from a non-local DSQ to a local DSQ and this operation was named "consume". This was already confusing as a task could be dispatched to a user DSQ from ops.enqueue() and then the DSQ would have to be consumed in ops.dispatch(). Later addition of scx_bpf_dispatch_from_dsq*() made the confusion even worse as "dispatch" in this context meant moving a task to an arbitrary DSQ from a user DSQ. Clean up the API with the following renames: 1. scx_bpf_dispatch[_vtime]() -> scx_bpf_dsq_insert[_vtime]() 2. scx_bpf_consume() -> scx_bpf_dsq_move_to_local() 3. scx_bpf_dispatch[_vtime]_from_dsq*() -> scx_bpf_dsq_move[_vtime]*() This patch performs the second rename. Compatibility is maintained by: - The previous kfunc names are still provided by the kernel so that old binaries can run. Kernel generates a warning when the old names are used. - compat.bpf.h provides wrappers for the new names which automatically fall back to the old names when running on older kernels. They also trigger build error if old names are used for new builds. The compat features will be dropped after v6.15. v2: Comment and documentation updates. Signed-off-by: Tejun Heo Acked-by: Andrea Righi Acked-by: Changwoo Min Acked-by: Johannes Bechberger Acked-by: Giovanni Gherdovich Cc: Dan Schatzberg Cc: Ming Yang

sched_ext: Rename scx_bpf_dispatch[_vtime]() to scx_bpf_dsq_insert[_vtime]()

2024-11-11T17:06:16+00:00

In sched_ext API, a repeatedly reported pain point is the overuse of the verb "dispatch" and confusion around "consume": - ops.dispatch() - scx_bpf_dispatch[_vtime]() - scx_bpf_consume() - scx_bpf_dispatch[_vtime]_from_dsq*() This overloading of the term is historical. Originally, there were only built-in DSQs and moving a task into a DSQ always dispatched it for execution. Using the verb "dispatch" for the kfuncs to move tasks into these DSQs made sense. Later, user DSQs were added and scx_bpf_dispatch[_vtime]() updated to be able to insert tasks into any DSQ. The only allowed DSQ to DSQ transfer was from a non-local DSQ to a local DSQ and this operation was named "consume". This was already confusing as a task could be dispatched to a user DSQ from ops.enqueue() and then the DSQ would have to be consumed in ops.dispatch(). Later addition of scx_bpf_dispatch_from_dsq*() made the confusion even worse as "dispatch" in this context meant moving a task to an arbitrary DSQ from a user DSQ. Clean up the API with the following renames: 1. scx_bpf_dispatch[_vtime]() -> scx_bpf_dsq_insert[_vtime]() 2. scx_bpf_consume() -> scx_bpf_dsq_move_to_local() 3. scx_bpf_dispatch[_vtime]_from_dsq*() -> scx_bpf_dsq_move[_vtime]*() This patch performs the first set of renames. Compatibility is maintained by: - The previous kfunc names are still provided by the kernel so that old binaries can run. Kernel generates a warning when the old names are used. - compat.bpf.h provides wrappers for the new names which automatically fall back to the old names when running on older kernels. They also trigger build error if old names are used for new builds. The compat features will be dropped after v6.15. v2: Documentation updates. Signed-off-by: Tejun Heo Acked-by: Andrea Righi Acked-by: Changwoo Min Acked-by: Johannes Bechberger Acked-by: Giovanni Gherdovich Cc: Dan Schatzberg Cc: Ming Yang

sched_ext: Enable the ops breather and eject BPF scheduler on softlockup

2024-11-08T20:42:22+00:00

On 2 x Intel Sapphire Rapids machines with 224 logical CPUs, a poorly behaving BPF scheduler can live-lock the system by making multiple CPUs bang on the same DSQ to the point where soft-lockup detection triggers before SCX's own watchdog can take action. It also seems possible that the machine can be live-locked enough to prevent scx_ops_helper, which is an RT task, from running in a timely manner. Implement scx_softlockup() which is called when three quarters of soft-lockup threshold has passed. The function immediately enables the ops breather and triggers an ops error to initiate ejection of the BPF scheduler. The previous and this patch combined enable the kernel to reliably recover the system from live-lock conditions that can be triggered by a poorly behaving BPF scheduler on Intel dual socket systems. Signed-off-by: Tejun Heo Cc: Douglas Anderson Cc: Andrew Morton

sched_ext: Update scx_show_state.py to match scx_ops_bypass_depth's new type

2024-11-05T21:45:27+00:00

0e7ffff1b811 ("scx: Fix raciness in scx_ops_bypass()") converted scx_ops_bypass_depth from an atomic to an int. Update scx_show_state.py accordingly. Signed-off-by: Tejun Heo Fixes: 0e7ffff1b811 ("scx: Fix raciness in scx_ops_bypass()")

sched_ext: Make cast_mask() inline

2024-10-25T22:19:44+00:00

cast_mask() doesn't do any actual work and is defined in a header file. Force it to be inline. When it is not inlined and the function is not used, it can cause verificaiton failures like the following: # tools/testing/selftests/sched_ext/runner -t minimal ===== START ===== TEST: minimal DESCRIPTION: Verify we can load a fully minimal scheduler OUTPUT: libbpf: prog 'cast_mask': missing BPF prog type, check ELF section name '.text' libbpf: prog 'cast_mask': failed to load: -22 libbpf: failed to load object 'minimal' libbpf: failed to load BPF skeleton 'minimal': -22 ERR: minimal.c:20 Failed to open and load skel not ok 1 minimal # ===== END ===== Signed-off-by: Tejun Heo Fixes: a748db0c8c6a ("tools/sched_ext: Receive misc updates from SCX repo")

sched_ext, scx_qmap: Add and use SCX_ENQ_CPU_SELECTED

2024-10-07T20:16:18+00:00

scx_qmap and other schedulers in the SCX repo are using SCX_ENQ_WAKEUP to tell whether ops.select_cpu() was called. This is incorrect as ops.select_cpu() can be skipped in the wakeup path and leads to e.g. incorrectly skipping direct dispatch for tasks that are bound to a single CPU. sched core has been updated to specify ENQUEUE_RQ_SELECTED if ->select_task_rq() was called. Map it to SCX_ENQ_CPU_SELECTED and update scx_qmap to test it instead of SCX_ENQ_WAKEUP. Signed-off-by: Tejun Heo Acked-by: David Vernet Cc: Daniel Hodges Cc: Changwoo Min Cc: Andrea Righi Cc: Dan Schatzberg

sched_ext: Add __weak markers to BPF helper function decalarations

2024-10-02T16:53:12+00:00

Fix build errors by adding __weak markers to BPF helper function declarations in header files. This resolves static assertion failures in scx_qmap.bpf.c and scx_flatcg.bpf.c where functions like scx_bpf_dispatch_from_dsq_set_slice, scx_bpf_dispatch_from_dsq_set_vtime, and scx_bpf_task_cgroup were missing the __weak attribute. [1] https://lore.kernel.org/all/ZvvfUqRNM4-jYQzH@linux.ibm.com Signed-off-by: Vishal Chourasia Signed-off-by: Tejun Heo