schedule: allocate the scheduler objects with sof_heap_alloc() by kv2019i · Pull Request #10821 · thesofproject/sof

kv2019i · 2026-05-28T14:41:16Z

Ensure the scheduler objects and lists of schedulers are allocated such that they can be used with both kernel and user-space LL scheduler implementations.

The SOF_MEM_FLAG_KERNEL flag is remevod. This flag has been a no-op for a while, and given scheduler list is not always in kernel anymore, it would be highly confusing to keep it.

When CONFIG_SOF_USERSPACE_LL is set, the context of all schedulers is managed in the LL user-space domain.

kv2019i · 2026-05-28T14:41:46Z

For context, part of #10558

Copilot

Pull request overview

This PR updates scheduler object allocation so scheduler state can reside in the appropriate heap for both kernel and userspace LL scheduler configurations.

Changes:

Replaces rzalloc(SOF_MEM_FLAG_KERNEL, ...) with sof_heap_alloc(...).
Selects the LL userspace heap when CONFIG_SOF_USERSPACE_LL is enabled.
Adds explicit zero-initialization after allocation to preserve previous rzalloc() behavior.

lgirdwood · 2026-05-28T20:50:44Z

+	struct k_heap *heap = NULL;
+
+#ifdef CONFIG_SOF_USERSPACE_LL
+	heap = sof_sys_user_heap_get();


whats the split between kernel/user memory for scheduler APIs for LL user ?

@lgirdwood The idea here is the audio schedulers (i.e. SOF schedule.h) are owned by the system LL thread (that can be now in user-space). This means we move other audio schedulers (DP, EDF) also to user-space. Only initial setup (and cleanup) is done from kernel.

lyakh · 2026-05-29T08:53:47Z

 		/* init schedulers list */
-		*sch = rzalloc(SOF_MEM_FLAG_KERNEL,
-			       sizeof(**sch));
+		*sch = sof_heap_alloc(heap, 0, sizeof(**sch), 0);


this would mean, that userspace code now effectively has access to all schedulers, also kernel ones

Ack. This does leave a gap with EDF currently, so this is not safe yet for production use. So in short, generic scheduler logic (Zephyr scheduling) in kernel, audio task scheduling in user-space (if SOF built for LL userspace).

kv2019i · 2026-06-01T11:00:15Z

Back to draft. I'll refactor this to follow a more conservative/opt-in approach where scheduler type can be moved (or not moved) one-by-one to user-space.

kv2019i · 2026-06-22T11:59:37Z

V2:

split scheduler state into kernel and user schedulers, allowing to move only LL to userspace and keep EDF still in kernel
marking again as ready for review

lgirdwood · 2026-06-22T12:14:40Z

+ * either holds all or subset of scheduler types.
+ * Not accessible from user-space threads.
+ */
+static struct schedulers *_schedulers[CONFIG_CORE_COUNT];


nitpick, we could put a k/u in the names if we have some static objects that are always kernel or always user, just to make sure we can visualize their usage better.

@lgirdwood I needed to respin, so added k/u_ prefix. Now need to follow same convention in other places. We do have the SYSUSER macro annotations, but these are not in the kernel objects, so additional prefix in the object name won't hurt.

lyakh

so does this mean now, that we don't need to access the global scheduler list from the userspace? Only respective individual schedulers?
But please check if those tiny functions can be inlined, would be much better that way.

lyakh · 2026-06-23T05:59:56Z


-	assert(schedulers);
+	assert(task && task->sch);
+	sch = task->sch;


...at some point would be good to have all these converted to

const struct scheduler_ops *ops = task->sch->ops; if (ops->x) return ops->x(...);

just to reduce the number of arrows that we carry around

lyakh · 2026-06-23T06:02:13Z

 	}

+#ifdef CONFIG_SOF_USERSPACE_LL
+	if (scheduler_is_user(type))


can we use if (IS_ENABLED(CONFIG_SOF_USERSPACE_LL) && scheduler_is_user(type)) here?

Done. This does require adding scheduler_is_user() to all builds, but should be ok (compiler can drop if not used).

lyakh · 2026-06-23T06:04:29Z

+	return NULL;
+#endif
+}
+EXPORT_SYMBOL(arch_user_schedulers_get_for_core);


can these be made static inline which would also avoid having to export them?

@lyakh these need to return an address to static objet, so cannot be inlined. I dropped the symbol export instead.

Add support for registering user-space LL tasks, and ability to use the task scheduling functions from user-space. The implementation splits scheduler list into kernel and user portions if SOF is built with CONFIG_SOF_USERSPACE_LL. A scheduler type can be either maintained in kernel or user, never both. With this patch, the SOF_SCHEDULE_LL_TIMER is moved to user managed if CONFIG_SOF_USERSPACE_LL is used. Signed-off-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>

Ensure the scheduler objects and lists of schedulers are allocated such that they can be used with both kernel and user-space LL scheduler implementations. The SOF_MEM_FLAG_KERNEL flag is removed. This flag has been a no-op for a while, and given scheduler list is not always in kernel anymore, it would be highly confusing to keep it. When CONFIG_SOF_USERSPACE_LL is set, the context of all schedulers is managed in the LL user-space domain. Signed-off-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>

kv2019i · 2026-06-24T13:09:32Z

V2 pushed:

added k_/u_ prefix to the added global as suggeted by @lgirdwood
moved to use IS_ENABLED() instead of ifdef (comment from @lyakh )
dropped the symbol exports (let's add them iff needed)

kv2019i requested review from Copilot, jsarha, lgirdwood and lyakh May 28, 2026 14:41

kv2019i requested review from LaurentiuM1234, dbaluta, marcinszkudlinski and pblaszko as code owners May 28, 2026 14:41

Copilot started reviewing on behalf of kv2019i May 28, 2026 14:41 View session

Copilot AI reviewed May 28, 2026

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lgirdwood reviewed May 28, 2026

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lyakh reviewed May 29, 2026

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kv2019i marked this pull request as draft June 1, 2026 10:59

kv2019i force-pushed the 202605-schedulers-use-heap-alloc branch from 1f2b5c4 to 8892eb0 Compare June 22, 2026 11:58

kv2019i marked this pull request as ready for review June 22, 2026 11:59

kv2019i requested review from abonislawski, iuliana-prodan, lbetlej, mmaka1 and plbossart as code owners June 22, 2026 11:59

lgirdwood approved these changes Jun 22, 2026

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lyakh requested changes Jun 23, 2026

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kv2019i added 2 commits June 24, 2026 13:45

kv2019i force-pushed the 202605-schedulers-use-heap-alloc branch from 8892eb0 to f398430 Compare June 24, 2026 13:08

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kv2019i commented May 28, 2026

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kv2019i commented Jun 1, 2026

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kv2019i commented Jun 24, 2026

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