* [PATCH] sched_ext: Remove deprecated scx_bpf_cpu_rq()
@ 2026-06-19 15:59 Christian Loehle
2026-06-19 18:53 ` Andrea Righi
0 siblings, 1 reply; 2+ messages in thread
From: Christian Loehle @ 2026-06-19 15:59 UTC (permalink / raw)
To: sched-ext
Cc: linux-kernel, tj, void, arighi, changwoo, gnq25, Christian Loehle
scx_bpf_cpu_rq() exposes rq pointers without requiring the rq lock and
has emitted a deprecation warning since commit
5c48d88fe004 ("sched_ext: deprecation warn for scx_bpf_cpu_rq()").
The supported replacements cover the intended uses:
scx_bpf_locked_rq() for locked rq access and
scx_bpf_cpu_curr() for remote curr lookup.
Remove the kfunc, its BTF registrations, the deprecation warning
state, and the BPF-side prototype and compat fallback.
Signed-off-by: Christian Loehle <christian.loehle@arm.com>
---
kernel/sched/ext.c | 30 ------------------------
kernel/sched/ext_internal.h | 1 -
tools/sched_ext/include/scx/common.bpf.h | 5 ++--
tools/sched_ext/include/scx/compat.bpf.h | 17 --------------
4 files changed, 2 insertions(+), 51 deletions(-)
diff --git a/kernel/sched/ext.c b/kernel/sched/ext.c
index 0db6fa2daea3..72d99dd3fe89 100644
--- a/kernel/sched/ext.c
+++ b/kernel/sched/ext.c
@@ -10222,34 +10222,6 @@ __bpf_kfunc s32 scx_bpf_task_cid(const struct task_struct *p)
return tbl[task_cpu(p)];
}
-/**
- * scx_bpf_cpu_rq - Fetch the rq of a CPU
- * @cpu: CPU of the rq
- * @aux: implicit BPF argument to access bpf_prog_aux hidden from BPF progs
- */
-__bpf_kfunc struct rq *scx_bpf_cpu_rq(s32 cpu, const struct bpf_prog_aux *aux)
-{
- struct scx_sched *sch;
-
- guard(rcu)();
-
- sch = scx_prog_sched(aux);
- if (unlikely(!sch))
- return NULL;
-
- if (!scx_cpu_valid(sch, 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);
-}
-
/**
* scx_bpf_locked_rq - Return the rq currently locked by SCX
* @aux: implicit BPF argument to access bpf_prog_aux hidden from BPF progs
@@ -10540,7 +10512,6 @@ BTF_ID_FLAGS(func, scx_bpf_put_cpumask, KF_RELEASE)
BTF_ID_FLAGS(func, scx_bpf_task_running, KF_RCU)
BTF_ID_FLAGS(func, scx_bpf_task_cpu, KF_RCU)
BTF_ID_FLAGS(func, scx_bpf_task_cid, KF_RCU)
-BTF_ID_FLAGS(func, scx_bpf_cpu_rq, KF_IMPLICIT_ARGS)
BTF_ID_FLAGS(func, scx_bpf_locked_rq, KF_IMPLICIT_ARGS | KF_RET_NULL)
BTF_ID_FLAGS(func, scx_bpf_cpu_curr, KF_IMPLICIT_ARGS | KF_RET_NULL | KF_RCU_PROTECTED)
BTF_ID_FLAGS(func, scx_bpf_cid_curr, KF_IMPLICIT_ARGS | KF_RET_NULL | KF_RCU_PROTECTED)
@@ -10575,7 +10546,6 @@ static const struct btf_kfunc_id_set scx_kfunc_set_any = {
BTF_KFUNCS_START(scx_kfunc_ids_cpu_only)
BTF_ID_FLAGS(func, scx_bpf_kick_cpu, KF_IMPLICIT_ARGS)
BTF_ID_FLAGS(func, scx_bpf_task_cpu, KF_RCU)
-BTF_ID_FLAGS(func, scx_bpf_cpu_rq, KF_IMPLICIT_ARGS)
BTF_ID_FLAGS(func, scx_bpf_cpu_curr, KF_IMPLICIT_ARGS | KF_RET_NULL | KF_RCU_PROTECTED)
BTF_ID_FLAGS(func, scx_bpf_cpu_node, KF_IMPLICIT_ARGS)
BTF_ID_FLAGS(func, scx_bpf_cpuperf_cap, KF_IMPLICIT_ARGS)
diff --git a/kernel/sched/ext_internal.h b/kernel/sched/ext_internal.h
index b04701190b23..38f099ccd24f 100644
--- a/kernel/sched/ext_internal.h
+++ b/kernel/sched/ext_internal.h
@@ -1165,7 +1165,6 @@ struct scx_sched {
* but it doesn't really matter.
*/
bool warned_zero_slice:1;
- bool warned_deprecated_rq:1;
bool warned_unassoc_progs:1;
struct list_head all;
diff --git a/tools/sched_ext/include/scx/common.bpf.h b/tools/sched_ext/include/scx/common.bpf.h
index 9591a6e778ce..bd51986c4c42 100644
--- a/tools/sched_ext/include/scx/common.bpf.h
+++ b/tools/sched_ext/include/scx/common.bpf.h
@@ -96,7 +96,6 @@ s32 scx_bpf_pick_any_cpu_node(const cpumask_t *cpus_allowed, int node, u64 flags
s32 scx_bpf_pick_any_cpu(const cpumask_t *cpus_allowed, u64 flags) __ksym;
bool scx_bpf_task_running(const struct task_struct *p) __ksym;
s32 scx_bpf_task_cpu(const struct task_struct *p) __ksym;
-struct rq *scx_bpf_cpu_rq(s32 cpu) __ksym;
struct rq *scx_bpf_locked_rq(void) __ksym;
struct task_struct *scx_bpf_cpu_curr(s32 cpu) __ksym __weak;
struct task_struct *scx_bpf_tid_to_task(u64 tid) __ksym __weak;
@@ -983,8 +982,8 @@ extern struct irqtime___local cpu_irqtime __ksym __weak;
static inline struct rq___local *get_current_rq(u32 cpu)
{
/*
- * This is a workaround to get an rq pointer since we decided to
- * deprecate scx_bpf_cpu_rq().
+ * This is a workaround to get an rq pointer now that
+ * scx_bpf_cpu_rq() has been removed.
*
* WARNING: The caller must hold the rq lock for @cpu. This is
* guaranteed when called from scheduling callbacks (ops.running,
diff --git a/tools/sched_ext/include/scx/compat.bpf.h b/tools/sched_ext/include/scx/compat.bpf.h
index 87f15f296234..133058578668 100644
--- a/tools/sched_ext/include/scx/compat.bpf.h
+++ b/tools/sched_ext/include/scx/compat.bpf.h
@@ -233,23 +233,6 @@ static inline bool __COMPAT_is_enq_cpu_selected(u64 enq_flags)
scx_bpf_pick_any_cpu_node(cpus_allowed, node, flags) : \
scx_bpf_pick_any_cpu(cpus_allowed, flags))
-/*
- * v6.18: Add a helper to retrieve the current task running on a CPU.
- *
- * Keep this helper available until v6.20 for compatibility.
- */
-static inline struct task_struct *__COMPAT_scx_bpf_cpu_curr(int cpu)
-{
- struct rq *rq;
-
- if (bpf_ksym_exists(scx_bpf_cpu_curr))
- return scx_bpf_cpu_curr(cpu);
-
- rq = scx_bpf_cpu_rq(cpu);
-
- return rq ? rq->curr : NULL;
-}
-
/*
* v6.19: To work around BPF maximum parameter limit, the following kfuncs are
* replaced with variants that pack scalar arguments in a struct. Wrappers are
--
2.34.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] sched_ext: Remove deprecated scx_bpf_cpu_rq()
2026-06-19 15:59 [PATCH] sched_ext: Remove deprecated scx_bpf_cpu_rq() Christian Loehle
@ 2026-06-19 18:53 ` Andrea Righi
0 siblings, 0 replies; 2+ messages in thread
From: Andrea Righi @ 2026-06-19 18:53 UTC (permalink / raw)
To: Christian Loehle; +Cc: sched-ext, linux-kernel, tj, void, changwoo, gnq25
Hi Christian,
On Fri, Jun 19, 2026 at 04:59:20PM +0100, Christian Loehle wrote:
> scx_bpf_cpu_rq() exposes rq pointers without requiring the rq lock and
> has emitted a deprecation warning since commit
> 5c48d88fe004 ("sched_ext: deprecation warn for scx_bpf_cpu_rq()").
> The supported replacements cover the intended uses:
> scx_bpf_locked_rq() for locked rq access and
> scx_bpf_cpu_curr() for remote curr lookup.
>
> Remove the kfunc, its BTF registrations, the deprecation warning
> state, and the BPF-side prototype and compat fallback.
>
> Signed-off-by: Christian Loehle <christian.loehle@arm.com>
It looks like none of the schedulers in the scx repo are using scx_bpf_cpu_rq()
anymore, so I think we can safely remove it.
Reviewed-by: Andrea Righi <arighi@nvidia.com>
Thanks,
-Andrea
> ---
> kernel/sched/ext.c | 30 ------------------------
> kernel/sched/ext_internal.h | 1 -
> tools/sched_ext/include/scx/common.bpf.h | 5 ++--
> tools/sched_ext/include/scx/compat.bpf.h | 17 --------------
> 4 files changed, 2 insertions(+), 51 deletions(-)
>
> diff --git a/kernel/sched/ext.c b/kernel/sched/ext.c
> index 0db6fa2daea3..72d99dd3fe89 100644
> --- a/kernel/sched/ext.c
> +++ b/kernel/sched/ext.c
> @@ -10222,34 +10222,6 @@ __bpf_kfunc s32 scx_bpf_task_cid(const struct task_struct *p)
> return tbl[task_cpu(p)];
> }
>
> -/**
> - * scx_bpf_cpu_rq - Fetch the rq of a CPU
> - * @cpu: CPU of the rq
> - * @aux: implicit BPF argument to access bpf_prog_aux hidden from BPF progs
> - */
> -__bpf_kfunc struct rq *scx_bpf_cpu_rq(s32 cpu, const struct bpf_prog_aux *aux)
> -{
> - struct scx_sched *sch;
> -
> - guard(rcu)();
> -
> - sch = scx_prog_sched(aux);
> - if (unlikely(!sch))
> - return NULL;
> -
> - if (!scx_cpu_valid(sch, 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);
> -}
> -
> /**
> * scx_bpf_locked_rq - Return the rq currently locked by SCX
> * @aux: implicit BPF argument to access bpf_prog_aux hidden from BPF progs
> @@ -10540,7 +10512,6 @@ BTF_ID_FLAGS(func, scx_bpf_put_cpumask, KF_RELEASE)
> BTF_ID_FLAGS(func, scx_bpf_task_running, KF_RCU)
> BTF_ID_FLAGS(func, scx_bpf_task_cpu, KF_RCU)
> BTF_ID_FLAGS(func, scx_bpf_task_cid, KF_RCU)
> -BTF_ID_FLAGS(func, scx_bpf_cpu_rq, KF_IMPLICIT_ARGS)
> BTF_ID_FLAGS(func, scx_bpf_locked_rq, KF_IMPLICIT_ARGS | KF_RET_NULL)
> BTF_ID_FLAGS(func, scx_bpf_cpu_curr, KF_IMPLICIT_ARGS | KF_RET_NULL | KF_RCU_PROTECTED)
> BTF_ID_FLAGS(func, scx_bpf_cid_curr, KF_IMPLICIT_ARGS | KF_RET_NULL | KF_RCU_PROTECTED)
> @@ -10575,7 +10546,6 @@ static const struct btf_kfunc_id_set scx_kfunc_set_any = {
> BTF_KFUNCS_START(scx_kfunc_ids_cpu_only)
> BTF_ID_FLAGS(func, scx_bpf_kick_cpu, KF_IMPLICIT_ARGS)
> BTF_ID_FLAGS(func, scx_bpf_task_cpu, KF_RCU)
> -BTF_ID_FLAGS(func, scx_bpf_cpu_rq, KF_IMPLICIT_ARGS)
> BTF_ID_FLAGS(func, scx_bpf_cpu_curr, KF_IMPLICIT_ARGS | KF_RET_NULL | KF_RCU_PROTECTED)
> BTF_ID_FLAGS(func, scx_bpf_cpu_node, KF_IMPLICIT_ARGS)
> BTF_ID_FLAGS(func, scx_bpf_cpuperf_cap, KF_IMPLICIT_ARGS)
> diff --git a/kernel/sched/ext_internal.h b/kernel/sched/ext_internal.h
> index b04701190b23..38f099ccd24f 100644
> --- a/kernel/sched/ext_internal.h
> +++ b/kernel/sched/ext_internal.h
> @@ -1165,7 +1165,6 @@ struct scx_sched {
> * but it doesn't really matter.
> */
> bool warned_zero_slice:1;
> - bool warned_deprecated_rq:1;
> bool warned_unassoc_progs:1;
>
> struct list_head all;
> diff --git a/tools/sched_ext/include/scx/common.bpf.h b/tools/sched_ext/include/scx/common.bpf.h
> index 9591a6e778ce..bd51986c4c42 100644
> --- a/tools/sched_ext/include/scx/common.bpf.h
> +++ b/tools/sched_ext/include/scx/common.bpf.h
> @@ -96,7 +96,6 @@ s32 scx_bpf_pick_any_cpu_node(const cpumask_t *cpus_allowed, int node, u64 flags
> s32 scx_bpf_pick_any_cpu(const cpumask_t *cpus_allowed, u64 flags) __ksym;
> bool scx_bpf_task_running(const struct task_struct *p) __ksym;
> s32 scx_bpf_task_cpu(const struct task_struct *p) __ksym;
> -struct rq *scx_bpf_cpu_rq(s32 cpu) __ksym;
> struct rq *scx_bpf_locked_rq(void) __ksym;
> struct task_struct *scx_bpf_cpu_curr(s32 cpu) __ksym __weak;
> struct task_struct *scx_bpf_tid_to_task(u64 tid) __ksym __weak;
> @@ -983,8 +982,8 @@ extern struct irqtime___local cpu_irqtime __ksym __weak;
> static inline struct rq___local *get_current_rq(u32 cpu)
> {
> /*
> - * This is a workaround to get an rq pointer since we decided to
> - * deprecate scx_bpf_cpu_rq().
> + * This is a workaround to get an rq pointer now that
> + * scx_bpf_cpu_rq() has been removed.
> *
> * WARNING: The caller must hold the rq lock for @cpu. This is
> * guaranteed when called from scheduling callbacks (ops.running,
> diff --git a/tools/sched_ext/include/scx/compat.bpf.h b/tools/sched_ext/include/scx/compat.bpf.h
> index 87f15f296234..133058578668 100644
> --- a/tools/sched_ext/include/scx/compat.bpf.h
> +++ b/tools/sched_ext/include/scx/compat.bpf.h
> @@ -233,23 +233,6 @@ static inline bool __COMPAT_is_enq_cpu_selected(u64 enq_flags)
> scx_bpf_pick_any_cpu_node(cpus_allowed, node, flags) : \
> scx_bpf_pick_any_cpu(cpus_allowed, flags))
>
> -/*
> - * v6.18: Add a helper to retrieve the current task running on a CPU.
> - *
> - * Keep this helper available until v6.20 for compatibility.
> - */
> -static inline struct task_struct *__COMPAT_scx_bpf_cpu_curr(int cpu)
> -{
> - struct rq *rq;
> -
> - if (bpf_ksym_exists(scx_bpf_cpu_curr))
> - return scx_bpf_cpu_curr(cpu);
> -
> - rq = scx_bpf_cpu_rq(cpu);
> -
> - return rq ? rq->curr : NULL;
> -}
> -
> /*
> * v6.19: To work around BPF maximum parameter limit, the following kfuncs are
> * replaced with variants that pack scalar arguments in a struct. Wrappers are
> --
> 2.34.1
>
^ permalink raw reply [flat|nested] 2+ messages in thread
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2026-06-19 15:59 [PATCH] sched_ext: Remove deprecated scx_bpf_cpu_rq() Christian Loehle
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