JakeHillion/scx-upstream
1
0
Fork 0
mirror of https://github.com/sched-ext/scx.git synced 2024-11-24 11:50:23 +00:00
Code Issues Packages Projects Releases Wiki Activity

layered: cleanup warnings in bpf compilation

Browse Source 
clang is correctly warning that we use various uninitialised variables. clean
these up so real errors are easier to read.

The largest change here is to non-topological layered_dispatch. The
matching_dsq logic seems to be incorrect. It checks whether an uninitialised
variable is 0, if it is sets it, then only uses the variable if the value is 0.
I have changed this to default to -1, then use the value if it is no longer -1.
This commit is contained in:
Jake Hillion 2024-10-08 16:23:24 +01:00
parent 2077b9a799
commit 85daa2be32
1 changed files with 4 additions and 19 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

23
scheds/rust/scx_layered/src/bpf/main.bpf.c
View File

@ -601,8 +601,6 @@ s32 pick_idle_no_topo(struct task_struct *p, s32 prev_cpu,
struct layer *layer, bool from_selcpu)
{
const struct cpumask *idle_cpumask;
struct cache_ctx *cachec;
struct node_ctx *nodec;
struct cpumask *layer_cpumask, *layered_cpumask;
s32 cpu;
@ -1018,21 +1016,8 @@ void try_preempt(s32 task_cpu, struct task_struct *p, struct task_ctx *tctx,
bpf_for(idx, 0, nr_possible_cpus) {
s32 cand = (preempt_cursor + idx) % nr_possible_cpus;
if (try_preempt_cpu(cand, p, cctx, tctx, layer, false)) {
/*
* Round-robining doesn't have to be strict. Let's
* not bother with atomic ops on $preempt_cursor.
*/
preempt_cursor = (cand + 1) % nr_possible_cpus;
struct cpu_ctx *new_cctx;
if ((new_cctx = lookup_cpu_ctx(cand))) {
if (new_cctx->node_idx != nodec->id && new_cctx->node_idx == nodec->id)
lstat_inc(LSTAT_PREEMPT_XLLC, layer, cctx);
if (new_cctx->node_idx != nodec->id)
lstat_inc(LSTAT_PREEMPT_XLLC, layer, cctx);
}
if (try_preempt_cpu(cand, p, cctx, tctx, layer, false))
return;
}
}
}
@ -1312,7 +1297,7 @@ void BPF_STRUCT_OPS(layered_dispatch, s32 cpu, struct task_struct *prev)
return;
} else {
u64 matching_dsq;
u64 matching_dsq = -1;
u64 non_preempting_open_dsq;
bpf_for(llc_id, 0, nr_llcs) {
@ -1326,7 +1311,7 @@ void BPF_STRUCT_OPS(layered_dispatch, s32 cpu, struct task_struct *prev)
return;
/* consume matching layers */
if (layer_matches && !matching_dsq){
if (layer_matches && matching_dsq == -1) {
matching_dsq = dsq_id;
break;
}
@ -1337,7 +1322,7 @@ void BPF_STRUCT_OPS(layered_dispatch, s32 cpu, struct task_struct *prev)
}
/* preserve priority order of dsq execution */
if(!matching_dsq) {
if (matching_dsq != -1) {
if (scx_bpf_consume(matching_dsq))
return;
}