Windows: avoid the loop starvation bug. Closes GH-154

joyent · Nov 28, 2011 · fce9065 · fce9065
1 parent 01f64f6
commit fce9065
Show file tree

Hide file tree

Showing 2 changed files with 20 additions and 30 deletions.
diff --git a/src/win/core.c b/src/win/core.c
@@ -204,21 +204,19 @@ static void uv_poll_ex(uv_loop_t* loop, int block) {
       uv_idle_invoke((loop));                                                 \
     }                                                                         \
                                                                               \
-    /* Completely flush all pending reqs and endgames. */                     \
-    /* We do even when we just called the idle callbacks because those may */ \
-    /* have closed handles or started requests that short-circuited. */       \
-    while ((loop)->pending_reqs_tail || (loop)->endgame_handles) {            \
-      uv_process_endgames((loop));                                            \
-      uv_process_reqs((loop));                                                \
-    }                                                                         \
+    uv_process_reqs((loop));                                                  \
+    uv_process_endgames((loop));                                              \
                                                                               \
     if ((loop)->refs <= 0) {                                                  \
       break;                                                                  \
     }                                                                         \
                                                                               \
     uv_prepare_invoke((loop));                                                \
                                                                               \
-    poll((loop), (loop)->idle_handles == NULL && (loop)->refs > 0);           \
+    poll((loop), (loop)->idle_handles == NULL &&                              \
+                 (loop)->pending_reqs_tail == NULL &&                         \
+                 (loop)->endgame_handles == NULL &&                           \
+                 (loop)->refs > 0);                                           \
                                                                               \
     uv_check_invoke((loop));                                                  \
   }

diff --git a/src/win/req.c b/src/win/req.c
@@ -51,27 +51,6 @@ void uv_insert_pending_req(uv_loop_t* loop, uv_req_t* req) {
 }
 
 
-static uv_req_t* uv_remove_pending_req(uv_loop_t* loop) {
-  uv_req_t* req;
-
-  if (loop->pending_reqs_tail) {
-    req = loop->pending_reqs_tail->next_req;
-
-    if (req == loop->pending_reqs_tail) {
-      loop->pending_reqs_tail = NULL;
-    } else {
-      loop->pending_reqs_tail->next_req = req->next_req;
-    }
-
-    return req;
-
-  } else {
-    /* queue empty */
-    return NULL;
-  }
-}
-
-
 #define DELEGATE_STREAM_REQ(loop, req, method, handle_at)                     \
   do {                                                                        \
     switch (((uv_handle_t*) (req)->handle_at)->type) {                        \
@@ -101,8 +80,21 @@ static uv_req_t* uv_remove_pending_req(uv_loop_t* loop) {
 
 void uv_process_reqs(uv_loop_t* loop) {
   uv_req_t* req;
+  uv_req_t* first;
+  uv_req_t* next;
+
+  if (loop->pending_reqs_tail == NULL) {
+    return;
+  }
+
+  first = loop->pending_reqs_tail->next_req;
+  next = first;
+  loop->pending_reqs_tail = NULL;
+
+  while (next != NULL) {
+    req = next;
+    next = req->next_req != first ? req->next_req : NULL;
 
-  while (req = uv_remove_pending_req(loop)) {
     switch (req->type) {
       case UV_READ:
         DELEGATE_STREAM_REQ(loop, req, read, data);