Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit e8693bcf authored by Christoph Hellwig's avatar Christoph Hellwig
Browse files

aio: allow direct aio poll comletions for keyed wakeups 



If we get a keyed wakeup for a aio poll waitqueue and wake can acquire the
ctx_lock without spinning we can just complete the iocb straight from the
wakeup callback to avoid a context switch.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Tested-by: default avatarAvi Kivity <avi@scylladb.com>
parent bfe4037e

fs/aio.c

+15 −2
Original line number Original line Diff line number Diff line
@@ -1672,14 +1672,27 @@ static int aio_poll_wake(struct wait_queue_entry *wait, unsigned mode, int sync, 
		void *key)

		void *key)

{

{

	struct poll_iocb *req = container_of(wait, struct poll_iocb, wait);

	struct poll_iocb *req = container_of(wait, struct poll_iocb, wait);

	struct aio_kiocb *iocb = container_of(req, struct aio_kiocb, poll);

	__poll_t mask = key_to_poll(key);

	__poll_t mask = key_to_poll(key);





	req->woken = true;

	req->woken = true;





	/* for instances that support it check for an event match first: */

	/* for instances that support it check for an event match first: */

	if (mask && !(mask & req->events))

	if (mask) {

		if (!(mask & req->events))

			return 0;

			return 0;





		/* try to complete the iocb inline if we can: */

		if (spin_trylock(&iocb->ki_ctx->ctx_lock)) {

			list_del(&iocb->ki_list);

			spin_unlock(&iocb->ki_ctx->ctx_lock);



			list_del_init(&req->wait.entry);

			aio_poll_complete(iocb, mask);

			return 1;

		}

	}



	list_del_init(&req->wait.entry);

	list_del_init(&req->wait.entry);

	schedule_work(&req->work);

	schedule_work(&req->work);

	return 1;

	return 1;