bpf: Allow reuse from waiting_for_gp_ttrace list.

alloc_bulk() can reuse elements from free_by_rcu_ttrace.
Let it reuse from waiting_for_gp_ttrace as well to avoid unnecessary kmalloc().

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20230706033447.54696-10-alexei.starovoitov@gmail.com
This commit is contained in:
Alexei Starovoitov 2023-07-05 20:34:42 -07:00 committed by Daniel Borkmann
parent 822fb26bdb
commit 04fabf00b4

View File

@ -212,6 +212,15 @@ static void alloc_bulk(struct bpf_mem_cache *c, int cnt, int node)
if (i >= cnt)
return;
for (; i < cnt; i++) {
obj = llist_del_first(&c->waiting_for_gp_ttrace);
if (!obj)
break;
add_obj_to_free_list(c, obj);
}
if (i >= cnt)
return;
memcg = get_memcg(c);
old_memcg = set_active_memcg(memcg);
for (; i < cnt; i++) {
@ -295,12 +304,7 @@ static void do_call_rcu_ttrace(struct bpf_mem_cache *c)
WARN_ON_ONCE(!llist_empty(&c->waiting_for_gp_ttrace));
llist_for_each_safe(llnode, t, llist_del_all(&c->free_by_rcu_ttrace))
/* There is no concurrent __llist_add(waiting_for_gp_ttrace) access.
* It doesn't race with llist_del_all either.
* But there could be two concurrent llist_del_all(waiting_for_gp_ttrace):
* from __free_rcu() and from drain_mem_cache().
*/
__llist_add(llnode, &c->waiting_for_gp_ttrace);
llist_add(llnode, &c->waiting_for_gp_ttrace);
if (unlikely(READ_ONCE(c->draining))) {
__free_rcu(&c->rcu_ttrace);