@@ -13,6 +13,11 @@ static void __io_notif_complete_tw(struct callback_head *cb)
struct io_notif *notif = container_of(cb, struct io_notif, task_work);
struct io_ring_ctx *ctx = notif->ctx;
+ if (likely(notif->task)) {
+ io_put_task(notif->task, 1);
+ notif->task = NULL;
+ }
+
io_cq_lock(ctx);
io_fill_cqe_aux(ctx, notif->tag, 0, notif->seq);
@@ -43,6 +48,14 @@ static void io_uring_tx_zerocopy_callback(struct sk_buff *skb,
if (!refcount_dec_and_test(&uarg->refcnt))
return;
+
+ if (likely(notif->task)) {
+ init_task_work(¬if->task_work, __io_notif_complete_tw);
+ if (likely(!task_work_add(notif->task, ¬if->task_work,
+ TWA_SIGNAL)))
+ return;
+ }
+
INIT_WORK(¬if->commit_work, io_notif_complete_wq);
queue_work(system_unbound_wq, ¬if->commit_work);
}
@@ -134,12 +147,15 @@ __cold int io_notif_unregister(struct io_ring_ctx *ctx)
for (i = 0; i < ctx->nr_notif_slots; i++) {
struct io_notif_slot *slot = &ctx->notif_slots[i];
- if (slot->notif)
- io_notif_slot_flush(slot);
+ if (!slot->notif)
+ continue;
+ if (WARN_ON_ONCE(slot->notif->task))
+ slot->notif->task = NULL;
+ io_notif_slot_flush(slot);
}
kvfree(ctx->notif_slots);
ctx->notif_slots = NULL;
ctx->nr_notif_slots = 0;
return 0;
-}
\ No newline at end of file
+}
@@ -11,6 +11,9 @@ struct io_notif {
struct ubuf_info uarg;
struct io_ring_ctx *ctx;
+ /* complete via tw if ->task is non-NULL, fallback to wq otherwise */
+ struct task_struct *task;
+
/* cqe->user_data, io_notif_slot::tag if not overridden */
u64 tag;
/* see struct io_notif_slot::seq */
We need a task context to post CQEs but using wq is too expensive. Try to complete notifiers using task_work and fall back to wq if fails. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> --- io_uring/notif.c | 22 +++++++++++++++++++--- io_uring/notif.h | 3 +++ 2 files changed, 22 insertions(+), 3 deletions(-)