GuillaumeHemmen/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2024-11-01 04:53:36 +01:00
Code Issues Projects Releases Packages Wiki Activity

sched_ext: Allow only user DSQs for scx_bpf_consume(), scx_bpf_dsq_nr_queued() and bpf_iter_scx_dsq_new()

Browse source 
SCX_DSQ_GLOBAL is special in that it can't be used as a priority queue and
is consumed implicitly, but all BPF DSQ related kfuncs could be used on it.
SCX_DSQ_GLOBAL will be split per-node for scalability and those operations
won't make sense anymore. Disallow SCX_DSQ_GLOBAL on scx_bpf_consume(),
scx_bpf_dsq_nr_queued() and bpf_iter_scx_dsq_new(). This means that
SCX_DSQ_GLOBAL can only be used as a dispatch target from BPF schedulers.

With scx_flatcg, which was using SCX_DSQ_GLOBAL as the fallback DSQ,
updated, this shouldn't affect any schedulers.

This leaves find_dsq_for_dispatch() the only user of find_non_local_dsq().
Open code and remove find_non_local_dsq().

Signed-off-by: tejun heo <tj@kernel.org>
Acked-by: David Vernet <void@manifault.com>
This commit is contained in:
Tejun Heo 2024-09-26 12:56:46 -10:00
parent c9c809f413
commit 63fb3ec805
1 changed files with 8 additions and 14 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

22
kernel/sched/ext.c
View file

@ -1808,16 +1808,6 @@ static struct scx_dispatch_q *find_user_dsq(u64 dsq_id)
return rhashtable_lookup_fast(&dsq_hash, &dsq_id, dsq_hash_params);
}
static struct scx_dispatch_q *find_non_local_dsq(u64 dsq_id)
{
lockdep_assert(rcu_read_lock_any_held());
if (dsq_id == SCX_DSQ_GLOBAL)
return &scx_dsq_global;
else
return find_user_dsq(dsq_id);
}
static struct scx_dispatch_q *find_dsq_for_dispatch(struct rq *rq, u64 dsq_id,
struct task_struct *p)
{
@ -1835,7 +1825,11 @@ static struct scx_dispatch_q *find_dsq_for_dispatch(struct rq *rq, u64 dsq_id,
return &cpu_rq(cpu)->scx.local_dsq;
}
dsq = find_non_local_dsq(dsq_id);
if (dsq_id == SCX_DSQ_GLOBAL)
dsq = &scx_dsq_global;
else
dsq = find_user_dsq(dsq_id);
if (unlikely(!dsq)) {
scx_ops_error("non-existent DSQ 0x%llx for %s[%d]",
dsq_id, p->comm, p->pid);
@ -6176,7 +6170,7 @@ __bpf_kfunc bool scx_bpf_consume(u64 dsq_id)
flush_dispatch_buf(dspc->rq);
dsq = find_non_local_dsq(dsq_id);
dsq = find_user_dsq(dsq_id);
if (unlikely(!dsq)) {
scx_ops_error("invalid DSQ ID 0x%016llx", dsq_id);
return false;
@ -6497,7 +6491,7 @@ __bpf_kfunc s32 scx_bpf_dsq_nr_queued(u64 dsq_id)
goto out;
}
} else {
dsq = find_non_local_dsq(dsq_id);
dsq = find_user_dsq(dsq_id);
if (dsq) {
ret = READ_ONCE(dsq->nr);
goto out;
@ -6546,7 +6540,7 @@ __bpf_kfunc int bpf_iter_scx_dsq_new(struct bpf_iter_scx_dsq *it, u64 dsq_id,
if (flags & ~__SCX_DSQ_ITER_USER_FLAGS)
return -EINVAL;
kit->dsq = find_non_local_dsq(dsq_id);
kit->dsq = find_user_dsq(dsq_id);
if (!kit->dsq)
return -ENOENT;