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authorMax Romanov <max.romanov@nginx.com>2020-10-28 00:01:46 +0300
committerMax Romanov <max.romanov@nginx.com>2020-10-28 00:01:46 +0300
commit4cb8aeb31a8cf47f6c61aaccb95bbbf47cbc2393 (patch)
tree381eed08e9d478216eed51ea0301dae63b7dc4da /src/nxt_port.h
parent131b6a7ffab7b3303a00a50f5cf764dc99e23cc0 (diff)
downloadunit-4cb8aeb31a8cf47f6c61aaccb95bbbf47cbc2393.tar.gz
unit-4cb8aeb31a8cf47f6c61aaccb95bbbf47cbc2393.tar.bz2
Router: introducing the PORT_ACK message.
The PORT_ACK message is the router's response to the application's NEW_PORT message. After receiving PORT_ACK, the application is safe to process requests using this port. This message avoids a racing condition when the application starts processing a request from the shared queue and sends REQ_HEADERS_ACK. The REQ_HEADERS_ACK message contains the application port ID as reply_port, which the router uses to send request data. When the application creates a new port, it immediately sends it to the main router thread. Because the request is processed outside the main thread, a racing condition can occur between the receipt of the new port in the main thread and the receipt of REQ_HEADERS_ACK in the worker router thread where the same port is specified as reply_port.
Diffstat (limited to '')
-rw-r--r--src/nxt_port.h3
1 files changed, 3 insertions, 0 deletions
diff --git a/src/nxt_port.h b/src/nxt_port.h
index 3ac8c735..5ece3bfa 100644
--- a/src/nxt_port.h
+++ b/src/nxt_port.h
@@ -26,6 +26,7 @@ struct nxt_port_handlers_s {
nxt_port_handler_t change_file;
nxt_port_handler_t new_port;
nxt_port_handler_t get_port;
+ nxt_port_handler_t port_ack;
nxt_port_handler_t mmap;
nxt_port_handler_t get_mmap;
@@ -84,6 +85,7 @@ typedef enum {
_NXT_PORT_MSG_CHANGE_FILE = nxt_port_handler_idx(change_file),
_NXT_PORT_MSG_NEW_PORT = nxt_port_handler_idx(new_port),
_NXT_PORT_MSG_GET_PORT = nxt_port_handler_idx(get_port),
+ _NXT_PORT_MSG_PORT_ACK = nxt_port_handler_idx(port_ack),
_NXT_PORT_MSG_MMAP = nxt_port_handler_idx(mmap),
_NXT_PORT_MSG_GET_MMAP = nxt_port_handler_idx(get_mmap),
@@ -120,6 +122,7 @@ typedef enum {
NXT_PORT_MSG_CHANGE_FILE = nxt_msg_last(_NXT_PORT_MSG_CHANGE_FILE),
NXT_PORT_MSG_NEW_PORT = nxt_msg_last(_NXT_PORT_MSG_NEW_PORT),
NXT_PORT_MSG_GET_PORT = nxt_msg_last(_NXT_PORT_MSG_GET_PORT),
+ NXT_PORT_MSG_PORT_ACK = nxt_msg_last(_NXT_PORT_MSG_PORT_ACK),
NXT_PORT_MSG_MMAP = nxt_msg_last(_NXT_PORT_MSG_MMAP)
| NXT_PORT_MSG_SYNC,
NXT_PORT_MSG_GET_MMAP = nxt_msg_last(_NXT_PORT_MSG_GET_MMAP),