sched_ext: deprecation warn for scx_bpf_cpu_rq()

scx_bpf_cpu_rq() works on an unlocked rq which generally isn't safe.
For the common use-cases scx_bpf_locked_rq() and
scx_bpf_cpu_curr() work, so add a deprecation warning
to scx_bpf_cpu_rq() so it can eventually be removed.

Signed-off-by: Christian Loehle <christian.loehle@arm.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
This commit is contained in:
Christian Loehle
2025-09-03 22:23:11 +01:00
committed by Tejun Heo
parent 20b158094a
commit 5c48d88fe0
2 changed files with 10 additions and 0 deletions

View File

@@ -6351,9 +6351,18 @@ __bpf_kfunc s32 scx_bpf_task_cpu(const struct task_struct *p)
*/
__bpf_kfunc struct rq *scx_bpf_cpu_rq(s32 cpu)
{
struct scx_sched *sch = scx_root;
if (!kf_cpu_valid(cpu, NULL))
return NULL;
if (!sch->warned_deprecated_rq) {
printk_deferred(KERN_WARNING "sched_ext: %s() is deprecated; "
"use scx_bpf_locked_rq() when holding rq lock "
"or scx_bpf_cpu_curr() to read remote curr safely.\n", __func__);
sch->warned_deprecated_rq = true;
}
return cpu_rq(cpu);
}

View File

@@ -872,6 +872,7 @@ struct scx_sched {
struct scx_sched_pcpu __percpu *pcpu;
bool warned_zero_slice;
bool warned_deprecated_rq;
atomic_t exit_kind;
struct scx_exit_info *exit_info;