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| author |   Tejun Heo <tj@kernel.org> | 2025-05-14 12:37:18 -0400 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2025-05-14 12:37:18 -0400 |
| commit | cb4ff91492de79e1dd1daacf75c2bd7c54d23252 (patch) | |
| tree | b87527388d4ad459ea7d7da76ebc7516802a1c64 /kernel | |
| parent | sched_ext: Add @sch to SCX_CALL_OP*() (diff) | |
| download | wireguard-linux-cb4ff91492de79e1dd1daacf75c2bd7c54d23252.tar.xz wireguard-linux-cb4ff91492de79e1dd1daacf75c2bd7c54d23252.zip | |
sched_ext: Explain the temporary situation around scx_root dereferences
Naked scx_root dereferences are being used as temporary markers to indicate
that they need to be updated to point to the right scheduler instance.
Explain the situation.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Andrea Righi <arighi@nvidia.com>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/sched/ext.c | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/kernel/sched/ext.c b/kernel/sched/ext.c index 38c37c842b3e..52e0f9553e73 100644 --- a/kernel/sched/ext.c +++ b/kernel/sched/ext.c @@ -1016,6 +1016,14 @@ enum scx_ops_state { #define SCX_OPSS_STATE_MASK ((1LU << SCX_OPSS_QSEQ_SHIFT) - 1) #define SCX_OPSS_QSEQ_MASK (~SCX_OPSS_STATE_MASK) +/* + * NOTE: sched_ext is in the process of growing multiple scheduler support and + * scx_root usage is in a transitional state. Naked dereferences are safe if the + * caller is one of the tasks attached to SCX and explicit RCU dereference is + * necessary otherwise. Naked scx_root dereferences trigger sparse warnings but + * are used as temporary markers to indicate that the dereferences need to be + * updated to point to the associated scheduler instances rather than scx_root. + */ static struct scx_sched __rcu *scx_root; /* |