0.8.6.28:

[sbcl.git] / src / code / gc.lisp

diff --git a/src/code/gc.lisp b/src/code/gc.lisp
index 684e926..10f4bce 100644 (file)
--- a/src/code/gc.lisp
+++ b/src/code/gc.lisp
@@ -186,9 +186,6 @@ and submit it as a patch."
 (declaim (type (or index null) *gc-trigger*))
 (defvar *gc-trigger* nil)
 
-;;; When >0, inhibits garbage collection.
-(defvar *gc-inhibit*) ; initialized in cold init
-
 ;;; When T, indicates that a GC should have happened but did not due to 
 ;;; *GC-INHIBIT*. 
 (defvar *need-to-collect-garbage* nil) ; initialized in cold init
@@ -233,32 +230,27 @@ and submit it as a patch."
 
 ;;; For GENCGC all generations < GEN will be GC'ed.
 
-(defvar *already-in-gc* nil "System is running SUB-GC")
-(defvar *gc-mutex* (sb!thread:make-mutex :name "GC Mutex"))
+(defvar *already-in-gc* 
+  (sb!thread:make-mutex :name "GC lock") "ID of thread running SUB-GC")
 
 (defun sub-gc (&key (gen 0) &aux (pre-gc-dynamic-usage (dynamic-usage)))
-  (when *already-in-gc* (return-from sub-gc nil))
-  (setf *need-to-collect-garbage* t)
-  (when (zerop *gc-inhibit*)
-    (sb!thread:with-recursive-lock (*gc-mutex*)
-      (let ((*already-in-gc* t))
-       (without-interrupts
-        (gc-stop-the-world)
-        #+nil
-        (dolist (h *before-gc-hooks*)
-          (carefully-funcall h))
-        (collect-garbage gen)
-        (incf *n-bytes-freed-or-purified*
-              (max 0 (- pre-gc-dynamic-usage (dynamic-usage))))
-        (setf *need-to-collect-garbage* nil)
-
-        (gc-start-the-world)))
-      (scrub-control-stack))
-    (dolist (h *after-gc-hooks*)
-      (carefully-funcall h)))
-  (values))
-       
-
+  (let ((me (sb!thread:current-thread-id)))
+    (when (eql (sb!thread::mutex-value *already-in-gc*) me) 
+      (return-from sub-gc nil))
+    (setf *need-to-collect-garbage* t)
+    (when (zerop *gc-inhibit*)
+      (loop
+       (sb!thread:with-mutex (*already-in-gc*)
+        (unless *need-to-collect-garbage* (return-from sub-gc nil))
+        (without-interrupts
+         (gc-stop-the-world)
+         (collect-garbage gen)
+         (incf *n-bytes-freed-or-purified*
+               (max 0 (- pre-gc-dynamic-usage (dynamic-usage))))
+         (scrub-control-stack)
+         (setf *need-to-collect-garbage* nil)
+         (dolist (h *after-gc-hooks*) (carefully-funcall h))
+         (gc-start-the-world)))))))
 
 ;;; This is the user-advertised garbage collection function.
 (defun gc (&key (gen 0) (full nil) &allow-other-keys)