Commit e5d1bc0a authored by Pavel Begunkov's avatar Pavel Begunkov Committed by Jens Axboe
Browse files

io_uring: defer flushing cached reqs 



Awhile there are requests in the allocation cache -- use them, only if
those ended go for the stashed memory in comp.free_list. As list
manipulation are generally heavy and are not good for caches, flush them
all or as much as can in one go.

Signed-off-by: default avatarPavel Begunkov <asml.silence@gmail.com>
[axboe: return success/failure from io_flush_cached_reqs()]
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent c5eef2b9

fs/io_uring.c

+19 −9
Original line number Diff line number Diff line
@@ -1952,25 +1952,35 @@ static inline void io_req_complete(struct io_kiocb *req, long res) 
	__io_req_complete(req, 0, res, 0);

}



static struct io_kiocb *io_alloc_req(struct io_ring_ctx *ctx)

static bool io_flush_cached_reqs(struct io_submit_state *state)

{

	struct io_submit_state *state = &ctx->submit_state;



	BUILD_BUG_ON(IO_REQ_ALLOC_BATCH > ARRAY_SIZE(state->reqs));



	if (!list_empty(&state->comp.free_list)) {

		struct io_kiocb *req;

	struct io_kiocb *req = NULL;



	while (!list_empty(&state->comp.free_list)) {

		req = list_first_entry(&state->comp.free_list, struct io_kiocb,

					compl.list);

		list_del(&req->compl.list);

		return req;

		state->reqs[state->free_reqs++] = req;

		if (state->free_reqs == ARRAY_SIZE(state->reqs))

			break;

	}



	return req != NULL;

}



static struct io_kiocb *io_alloc_req(struct io_ring_ctx *ctx)

{

	struct io_submit_state *state = &ctx->submit_state;



	BUILD_BUG_ON(IO_REQ_ALLOC_BATCH > ARRAY_SIZE(state->reqs));



	if (!state->free_reqs) {

		gfp_t gfp = GFP_KERNEL | __GFP_NOWARN;

		int ret;



		if (io_flush_cached_reqs(state))

			goto got_req;



		ret = kmem_cache_alloc_bulk(req_cachep, gfp, IO_REQ_ALLOC_BATCH,

					    state->reqs);
@@ -1986,7 +1996,7 @@ static struct io_kiocb *io_alloc_req(struct io_ring_ctx *ctx) 
		}

		state->free_reqs = ret;

	}



got_req:

	state->free_reqs--;

	return state->reqs[state->free_reqs];

}