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authorTejun Heo <tj@kernel.org>2026-05-10 23:08:16 +0300
committerTejun Heo <tj@kernel.org>2026-05-10 23:08:16 +0300
commitcceb8fa9cb2cf98e31d81ecf6353b6ba5ac57744 (patch)
treeb23930bc26d43e5459598b22c78b3f28a20fbd3c /include/linux
parent938dd9ab2bd7df0a7e58ce4249794156be9530b4 (diff)
downloadlinux-cceb8fa9cb2cf98e31d81ecf6353b6ba5ac57744.tar.xz
sched_ext: Replace SCX_TASK_OFF_TASKS flag with SCX_TASK_DEAD state
SCX_TASK_OFF_TASKS marked tasks already through sched_ext_dead() so cgroup task iteration would skip them. This can be expressed better with a task state. Replace the flag with SCX_TASK_DEAD. scx_disable_and_exit_task() resets state to NONE on its way out, so sched_ext_dead() now sets DEAD after the wrapper returns. The validation matrix grows NONE -> DEAD, warns on DEAD -> NONE, and tightens READY's predecessor to INIT or ENABLED so the new DEAD value cannot silently transition to READY. Prepares for the following enable vs dead race fix. Signed-off-by: Tejun Heo <tj@kernel.org> Reviewed-by: Andrea Righi <arighi@nvidia.com>
Diffstat (limited to 'include/linux')
-rw-r--r--include/linux/sched/ext.h9
1 files changed, 5 insertions, 4 deletions
diff --git a/include/linux/sched/ext.h b/include/linux/sched/ext.h
index adb9a4de068a..9f1a326ad03e 100644
--- a/include/linux/sched/ext.h
+++ b/include/linux/sched/ext.h
@@ -101,24 +101,25 @@ enum scx_ent_flags {
SCX_TASK_DEQD_FOR_SLEEP = 1 << 3, /* last dequeue was for SLEEP */
SCX_TASK_SUB_INIT = 1 << 4, /* task being initialized for a sub sched */
SCX_TASK_IMMED = 1 << 5, /* task is on local DSQ with %SCX_ENQ_IMMED */
- SCX_TASK_OFF_TASKS = 1 << 6, /* removed from scx_tasks by sched_ext_dead() */
/*
- * Bits 8 and 9 are used to carry task state:
+ * Bits 8 to 10 are used to carry task state:
*
* NONE ops.init_task() not called yet
* INIT ops.init_task() succeeded, but task can be cancelled
* READY fully initialized, but not in sched_ext
* ENABLED fully initialized and in sched_ext
+ * DEAD terminal state set by sched_ext_dead()
*/
- SCX_TASK_STATE_SHIFT = 8, /* bits 8 and 9 are used to carry task state */
- SCX_TASK_STATE_BITS = 2,
+ SCX_TASK_STATE_SHIFT = 8,
+ SCX_TASK_STATE_BITS = 3,
SCX_TASK_STATE_MASK = ((1 << SCX_TASK_STATE_BITS) - 1) << SCX_TASK_STATE_SHIFT,
SCX_TASK_NONE = 0 << SCX_TASK_STATE_SHIFT,
SCX_TASK_INIT = 1 << SCX_TASK_STATE_SHIFT,
SCX_TASK_READY = 2 << SCX_TASK_STATE_SHIFT,
SCX_TASK_ENABLED = 3 << SCX_TASK_STATE_SHIFT,
+ SCX_TASK_DEAD = 4 << SCX_TASK_STATE_SHIFT,
/*
* Bits 12 and 13 are used to carry reenqueue reason. In addition to