[PATCH 1/1] server: Try to send asyncs to threads in APC wait.

[Paul Gofman]

From: Paul Gofman

---
 dlls/kernel32/tests/pipe.c |  2 +-
 server/thread.c            | 36 ++++++++++++++++++++++--------------
 2 files changed, 23 insertions(+), 15 deletions(-)

diff --git a/dlls/kernel32/tests/pipe.c b/dlls/kernel32/tests/pipe.c
index aff65fe2864..74cb726110b 100644
--- a/dlls/kernel32/tests/pipe.c
+++ b/dlls/kernel32/tests/pipe.c
@@ -127,7 +127,7 @@ static void _test_not_signaled(unsigned line, HANDLE handle)
 #define test_signaled(h) _test_signaled(__LINE__,h)
 static void _test_signaled(unsigned line, HANDLE handle)
 {
-    DWORD res = WaitForSingleObject(handle, 0);
+    DWORD res = WaitForSingleObject(handle, 50);
     ok_(__FILE__,line)(res == WAIT_OBJECT_0, "WaitForSingleObject returned %lu\n", res);
 }

diff --git a/server/thread.c b/server/thread.c
index 56f57cefd8f..5da980c6c75 100644
--- a/server/thread.c
+++ b/server/thread.c
@@ -1090,9 +1090,23 @@ static inline int is_in_apc_wait( struct thread *thread )
             (thread->wait && (thread->wait->flags & SELECT_INTERRUPTIBLE)));
 }

+/* try to find a thread in APC wait */
+static struct thread *find_thread_in_apc_wait( struct process *process )
+{
+    struct thread *thread;
+
+    LIST_FOR_EACH_ENTRY( thread, &process->thread_list, struct thread, proc_entry )
+    {
+        if (thread->state == TERMINATED || !is_in_apc_wait( thread )) continue;
+        return thread;
+    }
+    return NULL;
+}
+
 /* queue an existing APC to a given thread */
 static int queue_apc( struct process *process, struct thread *thread, struct thread_apc *apc )
 {
+    struct thread *candidate;
     struct list *queue;

if (thread && thread->state == TERMINATED && process)
@@ -1100,19 +1114,7 @@ static int queue_apc( struct process *process, struct thread *thread, struct thr

if (!thread)  /* find a suitable thread inside the process */
     {
-        struct thread *candidate;
-
-        /* first try to find a waiting thread */
-        LIST_FOR_EACH_ENTRY( candidate, &process->thread_list, struct thread, proc_entry )
-        {
-            if (candidate->state == TERMINATED) continue;
-            if (is_in_apc_wait( candidate ))
-            {
-                thread = candidate;
-                break;
-            }
-        }
-        if (!thread)
+        if (!(thread = find_thread_in_apc_wait( process )))
         {
             /* then use the first one that accepts a signal */
             LIST_FOR_EACH_ENTRY( candidate, &process->thread_list, struct thread, proc_entry )
@@ -1134,7 +1136,13 @@ static int queue_apc( struct process *process, struct thread *thread, struct thr
         /* send signal for system APCs if needed */
         if (queue == &thread->system_apc && list_empty( queue ) && !is_in_apc_wait( thread ))
         {
-            if (!send_thread_signal( thread, SIGUSR1 )) return 0;
+            if (process && (candidate = find_thread_in_apc_wait( process )))
+            {
+                /* System APC which can be queued to any thread, found a thread in APC wait first. */
+                thread = candidate;
+                if (!(queue = get_apc_queue( thread, apc->call.type ))) return 1;
+            }
+            else if (!send_thread_signal( thread, SIGUSR1 )) return 0;
         }
         /* cancel a possible previous APC with the same owner */
         if (apc->owner) thread_cancel_apc( thread, apc->owner, apc->call.type );