diff options
| author | Tejun Heo <tj@kernel.org> | 2026-07-13 22:18:43 -1000 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2026-07-13 22:18:43 -1000 |
| commit | 61d564fcdfcd664f623d4175738a6ccee654ca02 (patch) | |
| tree | 60515a7db233e88ee977942568e1ccf1728ae4f2 | |
| parent | 147d1885f390bcfb929210814f86dc22b24c2631 (diff) | |
sched_ext: Assign a unique id to each scheduler instance
Neither a scx_sched pointer nor its cgroup id uniquely identifies a
scheduler instance. A freed sched's memory can be reallocated, and a cgroup
can detach one sched and attach another. Add a monotonic, never-reused u64
id. A later patch compares it to drop a slice request that outlived a change
of a task's owning scheduler.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Andrea Righi <arighi@nvidia.com>
| -rw-r--r-- | kernel/sched/ext/ext.c | 4 | ||||
| -rw-r--r-- | kernel/sched/ext/internal.h | 3 |
2 files changed, 7 insertions, 0 deletions
diff --git a/kernel/sched/ext/ext.c b/kernel/sched/ext/ext.c index 151befdc9602..14775e288a6e 100644 --- a/kernel/sched/ext/ext.c +++ b/kernel/sched/ext/ext.c @@ -108,6 +108,9 @@ static bool dsq_is_rq_owned(struct scx_dispatch_q *dsq) } } +/* Cursor for unique scx_sched instance ids. id 0 is reserved. */ +static atomic64_t scx_sched_id_cursor = ATOMIC64_INIT(0); + #ifdef CONFIG_EXT_SUB_SCHED /* * The sub sched being enabled. Used by scx_disable_and_exit_task() to exit @@ -6502,6 +6505,7 @@ struct scx_sched *scx_alloc_and_add_sched(struct scx_enable_cmd *cmd, level * sizeof(parent->ancestors[0])); sch->ancestors[level] = sch; sch->level = level; + sch->id = atomic64_inc_return(&scx_sched_id_cursor); if (ops->timeout_ms) sch->watchdog_timeout = msecs_to_jiffies(ops->timeout_ms); diff --git a/kernel/sched/ext/internal.h b/kernel/sched/ext/internal.h index e735812e77a5..ad98e3469b12 100644 --- a/kernel/sched/ext/internal.h +++ b/kernel/sched/ext/internal.h @@ -1445,6 +1445,9 @@ struct scx_sched { struct list_head all; + /* unique instance id, monotonic and never reused */ + u64 id; + #ifdef CONFIG_EXT_SUB_SCHED struct rhash_head hash_node; |