Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
sched_ext: Improve SCX_KF_DISPATCH comment
The comment for SCX_KF_DISPATCH was incomplete and didn't explain that
ops.dispatch() may temporarily release the rq lock, allowing ENQUEUE and
SELECT_CPU operations to be nested inside DISPATCH contexts.
Update the comment to clarify this nesting behavior and provide better
context for when these operations can occur within dispatch.
Acked-by: Andrea Righi <arighi@nvidia.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
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include/linux/sched/ext.h
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include/linux/sched/ext.h
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SCX_KF_UNLOCKED = 0, /* sleepable and not rq locked */
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/* ENQUEUE and DISPATCH may be nested inside CPU_RELEASE */
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SCX_KF_CPU_RELEASE = 1 << 0, /* ops.cpu_release() */
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/* ops.dequeue (in REST) may be nested inside DISPATCH */
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/*
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* ops.dispatch() may release rq lock temporarily and thus ENQUEUE and
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* SELECT_CPU may be nested inside. ops.dequeue (in REST) may also be
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* nested inside DISPATCH.
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*/
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SCX_KF_DISPATCH = 1 << 1, /* ops.dispatch() */
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SCX_KF_ENQUEUE = 1 << 2, /* ops.enqueue() and ops.select_cpu() */
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SCX_KF_SELECT_CPU = 1 << 3, /* ops.select_cpu() */