Changeset 3bd1d7d4 in mainline

Timestamp:

2018-06-19T19:48:14Z (6 years ago)

Author:

Jiří Zárevúcky <jiri.zarevucky@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

7d7bc09, 8751cf3

Parents:

5c76cc61

git-author:

Jiří Zárevúcky <jiri.zarevucky@…> (2018-05-31 18:05:11)

git-committer:

Jiří Zárevúcky <jiri.zarevucky@…> (2018-06-19 19:48:14)

Message:

async: Use a dedicated futex for client hash table.

File:

• uspace/lib/c/generic/async/server.c (modified) (7 diffs)

uspace/lib/c/generic/async/server.c

@@ -240 +240 @@
 }
 
+static futex_t client_futex = FUTEX_INITIALIZER;
 static hash_table_t client_hash_table;
-static hash_table_t conn_hash_table;
 
 // TODO: lockfree notification_queue?
@@ -249 +249 @@
 static FIBRIL_SEMAPHORE_INITIALIZE(notification_semaphore, 0);
 
+static sysarg_t notification_avail = 0;
+
+/* The remaining structures are guarded by async_futex. */
+static hash_table_t conn_hash_table;
 static LIST_INITIALIZE(timeout_list);
-
-static sysarg_t notification_avail = 0;
 
 static size_t client_key_hash(void *key)
@@ -339 +341 @@
         client_t *client = NULL;
 
-        futex_down(&async_futex);
+        futex_lock(&client_futex);
         ht_link_t *link = hash_table_find(&client_hash_table, &client_id);
         if (link) {
@@ -345 +347 @@
                 atomic_inc(&client->refcnt);
         } else if (create) {
+                // TODO: move the malloc out of critical section
                 client = malloc(sizeof(client_t));
                 if (client) {
@@ -355 +358 @@
         }
 
-        futex_up(&async_futex);
+        futex_unlock(&client_futex);
         return client;
 }
@@ -363 +366 @@
         bool destroy;
 
-        futex_down(&async_futex);
+        futex_lock(&client_futex);
 
         if (atomic_predec(&client->refcnt) == 0) {
@@ -371 +374 @@
                 destroy = false;
 
-        futex_up(&async_futex);
+        futex_unlock(&client_futex);
 
         if (destroy) {