Optimisations to the pdu queues

[deb_libnfs.git] / lib / pdu.c

diff --git a/lib/pdu.c b/lib/pdu.c
index 5def0bc5d9041363b2bc833b5f50677750e5c517..2f4761d20a2b87825d52c1c1f2df786ceb14c464 100644 (file)
--- a/lib/pdu.c
+++ b/lib/pdu.c
@@ -49,6 +49,35 @@
 #include "libnfs-raw.h"
 #include "libnfs-private.h"
 
+void rpc_reset_queue(struct rpc_queue *q)
+{
+       q->head = NULL;
+       q->tail = NULL;
+}
+
+/*
+ * Push to the tail end of the queue
+ */
+void rpc_enqueue(struct rpc_queue *q, struct rpc_pdu *pdu)
+{
+       if (q->head == NULL)
+               q->head = pdu;
+       else
+               q->tail->next = pdu;
+       q->tail = pdu;
+}
+
+/*
+ * Push to the front/head of the queue
+ */
+void rpc_return_to_queue(struct rpc_queue *q, struct rpc_pdu *pdu)
+{
+       pdu->next = q->head;
+       q->head = pdu;
+       if (q->tail == NULL)
+               q->tail = pdu;
+}
+
 struct rpc_pdu *rpc_allocate_pdu(struct rpc_context *rpc, int program, int version, int procedure, rpc_cb cb, void *private_data, zdrproc_t zdr_decode_fn, int zdr_decode_bufsize)
 {
        struct rpc_pdu *pdu;
@@ -135,7 +164,7 @@ int rpc_queue_pdu(struct rpc_context *rpc, struct rpc_pdu *pdu)
                        rpc_free_pdu(rpc, pdu);
                        return -1;
                }
-               SLIST_ADD_END(&rpc->waitpdu, pdu);
+               rpc_enqueue(&rpc->waitpdu, pdu);
                return 0;
        }
 
@@ -153,7 +182,7 @@ int rpc_queue_pdu(struct rpc_context *rpc, struct rpc_pdu *pdu)
        }
 
        memcpy(pdu->outdata.data, rpc->encodebuf, pdu->outdata.size);
-       SLIST_ADD_END(&rpc->outqueue, pdu);
+       rpc_enqueue(&rpc->outqueue, pdu);
 
        return 0;
 }
@@ -237,7 +266,7 @@ static int rpc_process_reply(struct rpc_context *rpc, struct rpc_pdu *pdu, ZDR *
 
 int rpc_process_pdu(struct rpc_context *rpc, char *buf, int size)
 {
-       struct rpc_pdu *pdu;
+       struct rpc_pdu *pdu, *prev_pdu;
        ZDR zdr;
        int pos, recordmarker = 0;
        uint32_t xid;
@@ -302,12 +331,22 @@ int rpc_process_pdu(struct rpc_context *rpc, char *buf, int size)
        }
        zdr_setpos(&zdr, pos);
 
-       for (pdu=rpc->waitpdu; pdu; pdu=pdu->next) {
+       /* Linear traverse singly-linked list, but track previous
+        * entry for optimised removal */
+       prev_pdu = NULL;
+       for (pdu=rpc->waitpdu.head; pdu; pdu=pdu->next) {
                if (pdu->xid != xid) {
+                       prev_pdu = pdu;
                        continue;
                }
                if (rpc->is_udp == 0 || rpc->is_broadcast == 0) {
-                       SLIST_REMOVE(&rpc->waitpdu, pdu);
+                       /* Singly-linked but we track head and tail */
+                       if (pdu == rpc->waitpdu.head)
+                               rpc->waitpdu.head = pdu->next;
+                       if (pdu == rpc->waitpdu.tail)
+                               rpc->waitpdu.tail = prev_pdu;
+                       if (prev_pdu != NULL)
+                               prev_pdu->next = pdu->next;
                }
                if (rpc_process_reply(rpc, pdu, &zdr) != 0) {
                        rpc_set_error(rpc, "rpc_procdess_reply failed");