Changeset cadfa8e in mainline

Timestamp:

2009-10-11T10:14:34Z (15 years ago)

Author:

Jakub Jermar <jakub@…>

Branches:

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

Children:

854ad23

Parents:

b6ee5b1

Message:

Experimental support for timeoutable fibril condition variables.

Location:

uspace/lib/libc

Files:

• generic/fibril_sync.c (modified) (3 diffs)
• include/async_priv.h (modified) (2 diffs)
• include/fibril_sync.h (modified) (2 diffs)

uspace/lib/libc/generic/fibril_sync.c

@@ -36 +36 @@
 #include <fibril.h>
 #include <async.h>
+#include <async_priv.h>
 #include <adt/list.h>
 #include <futex.h>
+#include <sys/time.h>
+#include <errno.h>
 #include <assert.h>
 
@@ -194 +197 @@
 }
 
-void fibril_condvar_wait(fibril_condvar_t *fcv, fibril_mutex_t *fm)
-{
-        fibril_t *f = (fibril_t *) fibril_get_id();
-
-        futex_down(&async_futex);
-        list_append(&f->link, &fcv->waiters);
+int
+fibril_condvar_wait_timeout(fibril_condvar_t *fcv, fibril_mutex_t *fm,
+    suseconds_t timeout)
+{
+        awaiter_t wdata;
+
+        if (timeout < 0)
+                return ETIMEOUT;
+
+        wdata.fid = fibril_get_id();
+        wdata.active = false;
+        
+        wdata.to_event.inlist = timeout > 0;
+        wdata.to_event.occurred = false;
+        link_initialize(&wdata.to_event.link);
+
+        wdata.wu_event.inlist = true;
+        link_initialize(&wdata.wu_event.link);
+
+        futex_down(&async_futex);
+        if (timeout) {
+                gettimeofday(&wdata.to_event.expires, NULL);
+                tv_add(&wdata.to_event.expires, timeout);
+                async_insert_timeout(&wdata);
+        }
+        list_append(&wdata.wu_event.link, &fcv->waiters);
         _fibril_mutex_unlock_unsafe(fm);
         fibril_switch(FIBRIL_TO_MANAGER);
         fibril_mutex_lock(fm);
+
+        /* async_futex not held after fibril_switch() */
+        futex_down(&async_futex);
+        if (wdata.to_event.inlist)
+                list_remove(&wdata.to_event.link);
+        if (wdata.wu_event.inlist)
+                list_remove(&wdata.wu_event.link);
+        futex_up(&async_futex);
+        
+        return wdata.to_event.occurred ? ETIMEOUT : EOK;
+}
+
+void fibril_condvar_wait(fibril_condvar_t *fcv, fibril_mutex_t *fm)
+{
+        int rc;
+
+        rc = fibril_condvar_wait_timeout(fcv, fm, 0);
+        assert(rc == EOK);
 }
 
@@ -208 +249 @@
 {
         link_t *tmp;
-        fibril_t *f;
+        awaiter_t *wdp;
 
         futex_down(&async_futex);
         while (!list_empty(&fcv->waiters)) {
                 tmp = fcv->waiters.next;
-                f = list_get_instance(tmp, fibril_t, link);
-                list_remove(&f->link);
-                fibril_add_ready((fid_t) f);
-                optimize_execution_power();
-                if (once)
-                        break;
+                wdp = list_get_instance(tmp, awaiter_t, wu_event.link);
+                list_remove(&wdp->wu_event.link);
+                wdp->wu_event.inlist = false;
+                if (!wdp->active) {
+                        wdp->active = true;
+                        fibril_add_ready(wdp->fid);
+                        optimize_execution_power();
+                        if (once)
+                                break;
+                }
         }
         futex_up(&async_futex);

uspace/lib/libc/include/async_priv.h

@@ -56 +56 @@
 } to_event_t;
 
+/** Structures of this type are used to track the wakeup events. */
+typedef struct {
+        /** If true, this struct is in a synchronization object wait queue. */
+        bool inlist;
+        
+        /** Wait queue linkage. */
+        link_t link;
+} wu_event_t;
+
+
 /** Structures of this type represent a waiting fibril. */
 typedef struct {
@@ -66 +76 @@
         /** Timeout wait data. */
         to_event_t to_event;
+        /** Wakeup wait data. */
+        wu_event_t wu_event;
 } awaiter_t;
 

uspace/lib/libc/include/fibril_sync.h

@@ -40 +40 @@
 #include <adt/list.h>
 #include <libarch/tls.h>
+#include <sys/time.h>
 
 typedef struct {
@@ -95 +96 @@
 
 extern void fibril_condvar_initialize(fibril_condvar_t *);
+extern int fibril_condvar_wait_timeout(fibril_condvar_t *, fibril_mutex_t *,
+    suseconds_t);
 extern void fibril_condvar_wait(fibril_condvar_t *, fibril_mutex_t *);
 extern void fibril_condvar_signal(fibril_condvar_t *);