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authorAndrea Righi <arighi@nvidia.com>2025-09-04 07:31:00 +0200
committerTejun Heo <tj@kernel.org>2025-09-03 20:40:45 -1000
commita08b4dcad9fae495bcd88b91fb3410abf77d268e (patch)
tree94121bede6979f2f00ac085cae16518990afaac2 /tools
parent5c48d88fe004988ec508923dbdd00549e65f4055 (diff)
tools/sched_ext: Add compat helper for scx_bpf_cpu_curr()
Introduce a compatibility helper that allows BPF schedulers to use scx_bpf_cpu_curr() on older kernels. Fixes: 20b158094a1ad ("sched_ext: Introduce scx_bpf_cpu_curr()") Cc: Christian Loehle <christian.loehle@arm.com> Signed-off-by: Andrea Righi <arighi@nvidia.com> Signed-off-by: Tejun Heo <tj@kernel.org>
Diffstat (limited to 'tools')
-rw-r--r--tools/sched_ext/include/scx/common.bpf.h2
-rw-r--r--tools/sched_ext/include/scx/compat.bpf.h17
2 files changed, 18 insertions, 1 deletions
diff --git a/tools/sched_ext/include/scx/common.bpf.h b/tools/sched_ext/include/scx/common.bpf.h
index 342c7c48df5a..06e2551033cb 100644
--- a/tools/sched_ext/include/scx/common.bpf.h
+++ b/tools/sched_ext/include/scx/common.bpf.h
@@ -104,7 +104,7 @@ 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;
+struct task_struct *scx_bpf_cpu_curr(s32 cpu) __ksym __weak;
struct cgroup *scx_bpf_task_cgroup(struct task_struct *p) __ksym __weak;
u64 scx_bpf_now(void) __ksym __weak;
void scx_bpf_events(struct scx_event_stats *events, size_t events__sz) __ksym __weak;
diff --git a/tools/sched_ext/include/scx/compat.bpf.h b/tools/sched_ext/include/scx/compat.bpf.h
index 36e0cd2fd4ed..dd9144624dc9 100644
--- a/tools/sched_ext/include/scx/compat.bpf.h
+++ b/tools/sched_ext/include/scx/compat.bpf.h
@@ -231,6 +231,23 @@ static inline bool __COMPAT_is_enq_cpu_selected(u64 enq_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;
+}
+
+/*
* Define sched_ext_ops. This may be expanded to define multiple variants for
* backward compatibility. See compat.h::SCX_OPS_LOAD/ATTACH().
*/