sched_ext: Add the @sch parameter to scx_dsq_insert_preamble/commit()

In preparation for multiple scheduler support, add the @sch parameter to
scx_dsq_insert_preamble/commit() and update the callers to read $scx_root
and pass it in. The passed in @sch parameter is not used yet.

Reviewed-by: Andrea Righi <arighi@nvidia.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

diff --git a/kernel/sched/ext.c b/kernel/sched/ext.c
index 8a8fd57c62c639f7e99f610ad7bee88d40f3fd0d..ed72de7d43d38103edf2111dc036cbd06977eaa2 100644 (file)
--- a/kernel/sched/ext.c
+++ b/kernel/sched/ext.c
@@ -5240,7 +5240,8 @@ void __init init_sched_ext_class(void)
 /********************************************************************************
  * Helpers that can be called from the BPF scheduler.
  */
-static bool scx_dsq_insert_preamble(struct task_struct *p, u64 enq_flags)
+static bool scx_dsq_insert_preamble(struct scx_sched *sch, struct task_struct *p,
+                                   u64 enq_flags)
 {
        if (!scx_kf_allowed(SCX_KF_ENQUEUE | SCX_KF_DISPATCH))
                return false;
@@ -5260,8 +5261,8 @@ static bool scx_dsq_insert_preamble(struct task_struct *p, u64 enq_flags)
        return true;
 }
 
-static void scx_dsq_insert_commit(struct task_struct *p, u64 dsq_id,
-                                 u64 enq_flags)
+static void scx_dsq_insert_commit(struct scx_sched *sch, struct task_struct *p,
+                                 u64 dsq_id, u64 enq_flags)
 {
        struct scx_dsp_ctx *dspc = this_cpu_ptr(scx_dsp_ctx);
        struct task_struct *ddsp_task;
@@ -5325,7 +5326,14 @@ __bpf_kfunc_start_defs();
 __bpf_kfunc void scx_bpf_dsq_insert(struct task_struct *p, u64 dsq_id, u64 slice,
                                    u64 enq_flags)
 {
-       if (!scx_dsq_insert_preamble(p, enq_flags))
+       struct scx_sched *sch;
+
+       guard(rcu)();
+       sch = rcu_dereference(scx_root);
+       if (unlikely(!sch))
+               return;
+
+       if (!scx_dsq_insert_preamble(sch, p, enq_flags))
                return;
 
        if (slice)
@@ -5333,7 +5341,7 @@ __bpf_kfunc void scx_bpf_dsq_insert(struct task_struct *p, u64 dsq_id, u64 slice
        else
                p->scx.slice = p->scx.slice ?: 1;
 
-       scx_dsq_insert_commit(p, dsq_id, enq_flags);
+       scx_dsq_insert_commit(sch, p, dsq_id, enq_flags);
 }
 
 /**
@@ -5360,7 +5368,14 @@ __bpf_kfunc void scx_bpf_dsq_insert(struct task_struct *p, u64 dsq_id, u64 slice
 __bpf_kfunc void scx_bpf_dsq_insert_vtime(struct task_struct *p, u64 dsq_id,
                                          u64 slice, u64 vtime, u64 enq_flags)
 {
-       if (!scx_dsq_insert_preamble(p, enq_flags))
+       struct scx_sched *sch;
+
+       guard(rcu)();
+       sch = rcu_dereference(scx_root);
+       if (unlikely(!sch))
+               return;
+
+       if (!scx_dsq_insert_preamble(sch, p, enq_flags))
                return;
 
        if (slice)
@@ -5370,7 +5385,7 @@ __bpf_kfunc void scx_bpf_dsq_insert_vtime(struct task_struct *p, u64 dsq_id,
 
        p->scx.dsq_vtime = vtime;
 
-       scx_dsq_insert_commit(p, dsq_id, enq_flags | SCX_ENQ_DSQ_PRIQ);
+       scx_dsq_insert_commit(sch, p, dsq_id, enq_flags | SCX_ENQ_DSQ_PRIQ);
 }
 
 __bpf_kfunc_end_defs();