daemon/session2: optimize allocations

A) Context-specific allocations
-------------------------------

There were two problems:

1) Some payloads are short-lived (e.g. allocated on stack) and we need
   to make a copy of them if the iteration over protocol layers becomes
   asynchronous.
2) The `pl_dns_stream_wrap` function used a mempool belonging to its
   session-wide context. Some sessions may live for a long time, which
   could potentially lead to needlessly long-lived memory allocations.

Both of these problems are solved in this commit by using a new
`knot_mm_t pool` field in `struct protolayer_iter_ctx`, which lives only
for a single submit (and survives asynchronicity). The whole pool is
then freed all at once when the `struct protolayer_iter_ctx` is
finalized.

B) Merging `struct protolayer_manager` into `struct session2`
-------------------------------------------------------------

It actually made no real sense to have the two separated. It only
introduced an extra layer of indirection and many layers actually needed
to access both anyway. This should simplify things considerably.

1 files changed, 11 insertions, 11 deletions

diff --git a/daemon/io.c b/daemon/io.c
index d19da0eb..d219f592 100644
--- a/daemon/io.c
+++ b/daemon/io.c
@@ -49,7 +49,7 @@ static void check_bufsize(uv_handle_t* handle)
 static void handle_getbuf(uv_handle_t* handle, size_t suggested_size, uv_buf_t* buf)
 {
 	struct session2 *s = handle->data;
-	struct wire_buf *wb = &s->layers->wire_buf;
+	struct wire_buf *wb = &s->wire_buf;
 
 	buf->base = wire_buf_free_space(wb);
 	buf->len = wire_buf_free_space_length(wb);
@@ -58,7 +58,7 @@ static void handle_getbuf(uv_handle_t* handle, size_t suggested_size, uv_buf_t*
 static void udp_on_unwrapped(int status, struct session2 *session,
                              const struct comm_info *comm, void *baton)
 {
-	wire_buf_reset(&session->layers->wire_buf);
+	wire_buf_reset(&session->wire_buf);
 }
 
 void udp_recv(uv_udp_t *handle, ssize_t nread, const uv_buf_t *buf,
@@ -87,9 +87,9 @@ void udp_recv(uv_udp_t *handle, ssize_t nread, const uv_buf_t *buf,
 		return;
 	}
 
-	int ret = wire_buf_consume(&s->layers->wire_buf, nread);
+	int ret = wire_buf_consume(&s->wire_buf, nread);
 	if (ret) {
-		wire_buf_reset(&s->layers->wire_buf);
+		wire_buf_reset(&s->wire_buf);
 		return;
 	}
 
@@ -97,7 +97,7 @@ void udp_recv(uv_udp_t *handle, ssize_t nread, const uv_buf_t *buf,
 		.comm_addr = comm_addr,
 		.src_addr = comm_addr
 	};
-	session2_unwrap(s, protolayer_payload_wire_buf(&s->layers->wire_buf, false),
+	session2_unwrap(s, protolayer_payload_wire_buf(&s->wire_buf, true),
 			&in_comm, udp_on_unwrapped, NULL);
 }
 
@@ -138,7 +138,7 @@ static int family_to_freebind_option(sa_family_t sa_family, int *level, int *nam
 
 static enum protolayer_event_cb_result pl_udp_event_wrap(
 		enum protolayer_event_type event, void **baton,
-		struct protolayer_manager *manager, void *sess_data)
+		struct session2 *session, void *sess_data)
 {
 	if (event == PROTOLAYER_EVENT_STATS_SEND_ERR) {
 		the_worker->stats.err_udp += 1;
@@ -153,7 +153,7 @@ static enum protolayer_event_cb_result pl_udp_event_wrap(
 
 static enum protolayer_event_cb_result pl_tcp_event_wrap(
 		enum protolayer_event_type event, void **baton,
-		struct protolayer_manager *manager, void *sess_data)
+		struct session2 *session, void *sess_data)
 {
 	if (event == PROTOLAYER_EVENT_STATS_SEND_ERR) {
 		the_worker->stats.err_tcp += 1;
@@ -306,17 +306,17 @@ static void tcp_recv(uv_stream_t *handle, ssize_t nread, const uv_buf_t *buf)
 		return;
 	}
 
-	if (kr_fails_assert(buf->base == wire_buf_free_space(&s->layers->wire_buf))) {
+	if (kr_fails_assert(buf->base == wire_buf_free_space(&s->wire_buf))) {
 		return;
 	}
 
-	int ret = wire_buf_consume(&s->layers->wire_buf, nread);
+	int ret = wire_buf_consume(&s->wire_buf, nread);
 	if (ret) {
-		wire_buf_reset(&s->layers->wire_buf);
+		wire_buf_reset(&s->wire_buf);
 		return;
 	}
 
-	session2_unwrap(s, protolayer_payload_wire_buf(&s->layers->wire_buf, false),
+	session2_unwrap(s, protolayer_payload_wire_buf(&s->wire_buf, false),
 			NULL, NULL, NULL);
 }