Changeset 8dab988 in mainline

Timestamp:

2018-06-27T18:44:07Z (6 years ago)

Author:

Jiří Zárevúcky <jiri.zarevucky@…>

Branches:

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

Children:

62c4297

Parents:

45c39ad

Message:

Put notifications into a dynamic queue instead of forgetting them.

File:

• uspace/lib/c/generic/async/server.c (modified) (9 diffs)

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

@@ -122 +122 @@
 #include "../private/fibril.h"
 
+#define DPRINTF(...)  ((void) 0)
+
 /** Async framework global futex */
 futex_t async_futex = FUTEX_INITIALIZER;
@@ -180 +182 @@
 } connection_t;
 
+/* Member of notification_t::msg_list. */
+typedef struct {
+        link_t link;
+        ipc_call_t calldata;
+} notification_msg_t;
+
 /* Notification data */
 typedef struct {
@@ -197 +205 @@
         void *arg;
 
-        /** Data of the most recent notification. */
-        ipc_call_t calldata;
-
-        /**
-         * How many notifications with this `imethod` arrived since it was last
-         * handled. If `count` > 1, `calldata` only holds the data for the most
-         * recent such notification, all the older data being lost.
-         *
-         * `async_spawn_notification_handler()` can be used to increase the
-         * number of notifications that can be processed simultaneously,
-         * reducing the likelihood of losing them when the handler blocks.
-         */
-        long count;
+        /** List of arrived notifications. */
+        list_t msg_list;
 } notification_t;
 
@@ -249 +246 @@
 static LIST_INITIALIZE(notification_queue);
 static FIBRIL_SEMAPHORE_INITIALIZE(notification_semaphore, 0);
+
+static LIST_INITIALIZE(notification_freelist);
+static long notification_freelist_total = 0;
+static long notification_freelist_used = 0;
 
 static sysarg_t notification_avail = 0;
@@ -709 +710 @@
                 notification_t *notification = list_get_instance(
                     list_first(&notification_queue), notification_t, qlink);
-                list_remove(&notification->qlink);
 
                 async_notification_handler_t handler = notification->handler;
                 void *arg = notification->arg;
-                ipc_call_t calldata = notification->calldata;
-                long count = notification->count;
-
-                notification->count = 0;
+
+                notification_msg_t *m = list_pop(&notification->msg_list,
+                    notification_msg_t, link);
+                assert(m);
+                ipc_call_t calldata = m->calldata;
+
+                notification_freelist_used--;
+
+                if (notification_freelist_total > 64 &&
+                    notification_freelist_total > 2 * notification_freelist_used) {
+                        /* Going to free the structure if we have too much. */
+                        notification_freelist_total--;
+                } else {
+                        /* Otherwise add to freelist. */
+                        list_append(&m->link, &notification_freelist);
+                        m = NULL;
+                }
+
+                if (list_empty(&notification->msg_list))
+                        list_remove(&notification->qlink);
 
                 futex_unlock(&notification_futex);
-
-                // FIXME: Pass count to the handler. It might be important.
-                (void) count;
 
                 if (handler)
                         handler(&calldata, arg);
+
+                free(m);
         }
 
@@ -760 +775 @@
         futex_lock(&notification_futex);
 
+        notification_msg_t *m = list_pop(&notification_freelist,
+            notification_msg_t, link);
+
+        if (!m) {
+                futex_unlock(&notification_futex);
+                m = malloc(sizeof(notification_msg_t));
+                if (!m) {
+                        DPRINTF("Out of memory.\n");
+                        abort();
+                }
+
+                futex_lock(&notification_futex);
+                notification_freelist_total++;
+        }
+
         ht_link_t *link = hash_table_find(&notification_hash_table,
             &IPC_GET_IMETHOD(*call));
@@ -765 +795 @@
                 /* Invalid notification. */
                 // TODO: Make sure this can't happen and turn it into assert.
+                notification_freelist_total--;
                 futex_unlock(&notification_futex);
+                free(m);
                 return;
         }
@@ -772 +804 @@
             hash_table_get_inst(link, notification_t, htlink);
 
-        notification->count++;
-        notification->calldata = *call;
-
-        if (link_in_use(&notification->qlink)) {
-                /* Notification already queued. */
-                futex_unlock(&notification_futex);
-                return;
-        }
-
-        list_append(&notification->qlink, &notification_queue);
+        notification_freelist_used++;
+        m->calldata = *call;
+        list_append(&m->link, &notification->msg_list);
+
+        if (!link_in_use(&notification->qlink))
+                list_append(&notification->qlink, &notification_queue);
+
         futex_unlock(&notification_futex);
 
@@ -802 +831 @@
         notification->handler = handler;
         notification->arg = arg;
+
+        list_initialize(&notification->msg_list);
 
         fid_t fib = 0;