1.0.16.19: cleanups motivated by clisp host-2
[sbcl.git] / src / code / gc.lisp
index b9d7fb1..e6abbb1 100644 (file)
 (defun control-stack-usage ()
   #!-stack-grows-downward-not-upward
   (- (sb!sys:sap-int (sb!c::control-stack-pointer-sap))
-     (sb!vm:fixnumize sb!vm:*control-stack-start*))
+     (sb!sys:sap-int (sb!di::descriptor-sap sb!vm:*control-stack-start*)))
   #!+stack-grows-downward-not-upward
-  (- (sb!vm:fixnumize sb!vm:*control-stack-end*)
+  (- (sb!sys:sap-int (sb!di::descriptor-sap sb!vm:*control-stack-end*))
      (sb!sys:sap-int (sb!c::control-stack-pointer-sap))))
 
 (defun binding-stack-usage ()
   (- (sb!sys:sap-int (sb!c::binding-stack-pointer-sap))
-     (sb!vm:fixnumize sb!vm:*binding-stack-start*)))
+     (sb!sys:sap-int (sb!di::descriptor-sap sb!vm:*binding-stack-start*))))
 \f
 ;;;; ROOM
 
 (defun gc-reinit ()
   (gc-on)
   (gc)
-  (setf *n-bytes-freed-or-purified* 0))
+  (setf *n-bytes-freed-or-purified* 0
+        *gc-run-time* 0
+        ;; See comment in interr.lisp
+        *heap-exhausted-error-condition* (make-condition 'heap-exhausted-error)))
 
-(declaim (ftype (function () unsigned-byte) get-bytes-consed))
+(declaim (ftype (sfunction () unsigned-byte) get-bytes-consed))
 (defun get-bytes-consed ()
   #!+sb-doc
   "Return the number of bytes consed since the program began. Typically
@@ -137,8 +140,9 @@ and submit it as a patch."
 ;;;; GC hooks
 
 (defvar *after-gc-hooks* nil
-  "Called after each garbage collection. In a multithreaded
-environment these hooks may run in any thread.")
+  "Called after each garbage collection, except for garbage collections
+triggered during thread exits. In a multithreaded environment these hooks may
+run in any thread.")
 
 \f
 ;;;; internal GC
@@ -176,44 +180,75 @@ environment these hooks may run in any thread.")
 (defvar *already-in-gc*
   (sb!thread:make-mutex :name "GC lock") "ID of thread running SUB-GC")
 
+;;; A unique GC id. This is supplied for code that needs to detect
+;;; whether a GC has happened since some earlier point in time. For
+;;; example:
+;;;
+;;;   (let ((epoch *gc-epoch*))
+;;;      ...
+;;;      (unless (eql epoch *gc-epoch)
+;;;        ....))
+;;;
+;;; This isn't just a fixnum counter since then we'd have theoretical
+;;; problems when exactly 2^29 GCs happen between epoch
+;;; comparisons. Unlikely, but the cost of using a cons instead is too
+;;; small to measure. -- JES, 2007-09-30
+(declaim (type cons *gc-epoch*))
+(defvar *gc-epoch* (cons nil nil))
+
 (defun sub-gc (&key (gen 0))
   (unless (eq sb!thread:*current-thread*
-              (sb!thread::mutex-value *already-in-gc*))
+              (sb!thread:mutex-value *already-in-gc*))
     ;; With gencgc, unless *GC-PENDING* every allocation in this
     ;; function triggers another gc, potentially exceeding maximum
-    ;; interrupt nesting.
-    (setq *gc-pending* t)
-    (unless *gc-inhibit*
-      (sb!thread:with-mutex (*already-in-gc*)
-        (let ((old-usage (dynamic-usage))
-              (new-usage 0))
-          (unsafe-clear-roots)
-          ;; We need to disable interrupts for GC, but we also want
-          ;; to run as little as possible without them.
-          (without-interrupts
-            (gc-stop-the-world)
-            (collect-garbage gen)
-            (setf *gc-pending* nil
-                  new-usage (dynamic-usage))
-            (gc-start-the-world))
-          ;; Interrupts re-enabled, but still inside the mutex.
-          ;; In a multithreaded environment the other threads will
-          ;; see *n-b-f-o-p* change a little late, but that's OK.
-          (let ((freed (- old-usage new-usage)))
-            ;; GENCGC occasionally reports negative here, but the
-            ;; current belief is that it is part of the normal order
-            ;; of things and not a bug.
-            (when (plusp freed)
-              (incf *n-bytes-freed-or-purified* freed)))))
-      ;; Outside the mutex, these may cause another GC. FIXME: it can
-      ;; potentially exceed maximum interrupt nesting by triggering
-      ;; GCs.
-      (run-pending-finalizers)
-      (dolist (hook *after-gc-hooks*)
-        (handler-case
-            (funcall hook)
-          (error (c)
-            (warn "Error calling after GC hook ~S:~%  ~S" hook c)))))))
+    ;; interrupt nesting. If *GC-INHIBIT* is not true, however,
+    ;; there is no guarantee that we would ever check for pending
+    ;; GC -- so in that case we must first disable interrupts, which
+    ;; needs to be done for GC anyways...
+    (cond (*gc-inhibit*
+           (setf *gc-pending* t))
+          (t
+           (without-interrupts
+             (setf *gc-pending* t)
+             (sb!thread:with-mutex (*already-in-gc*)
+               (let ((old-usage (dynamic-usage))
+                     (new-usage 0))
+                 (unsafe-clear-roots)
+
+                 (gc-stop-the-world)
+                 (let ((start-time (get-internal-run-time)))
+                   (collect-garbage gen)
+                   (setf *gc-epoch* (cons nil nil))
+                   (incf *gc-run-time*
+                         (- (get-internal-run-time) start-time)))
+                 (setf *gc-pending* nil
+                       new-usage (dynamic-usage))
+                 (gc-start-the-world)
+
+                 ;; In a multithreaded environment the other threads will
+                 ;; see *n-b-f-o-p* change a little late, but that's OK.
+                 (let ((freed (- old-usage new-usage)))
+                   ;; GENCGC occasionally reports negative here, but the
+                   ;; current belief is that it is part of the normal order
+                   ;; of things and not a bug.
+                   (when (plusp freed)
+                     (incf *n-bytes-freed-or-purified* freed))))))
+
+           ;; Outside the mutex, interrupts enabled: these may cause
+           ;; another GC. FIXME: it can potentially exceed maximum
+           ;; interrupt nesting by triggering GCs.
+           ;;
+           ;; Can that be avoided by having the finalizers and hooks
+           ;; run only from the outermost SUB-GC?
+           ;;
+           ;; KLUDGE: Don't run the hooks in GC's triggered by dying
+           ;; threads, so that user-code never runs with
+           ;;   (thread-alive-p *current-thread*) => nil
+           ;; The long-term solution will be to keep a separate thread
+           ;; for finalizers and after-gc hooks.
+           (when (sb!thread:thread-alive-p sb!thread:*current-thread*)
+             (run-pending-finalizers)
+             (call-hooks "after-GC" *after-gc-hooks* :on-error :warn))))))
 
 ;;; This is the user-advertised garbage collection function.
 (defun gc (&key (gen 0) (full nil) &allow-other-keys)
@@ -230,6 +265,9 @@ environment these hooks may run in any thread.")
   ;; as having these cons more then we have space left leads to huge
   ;; badness.
   (scrub-control-stack)
+  ;; Power cache of the bignum printer: drops overly large bignums and
+  ;; removes duplicate entries.
+  (scrub-power-cache)
   ;; FIXME: CTYPE-OF-CACHE-CLEAR isn't thread-safe.
   #!-sb-thread
   (ctype-of-cache-clear))
@@ -250,16 +288,20 @@ environment these hooks may run in any thread.")
                                (sb!alien:unsigned 32))
         val))
 
+(declaim (inline maybe-handle-pending-gc))
+(defun maybe-handle-pending-gc ()
+  (when (and (not *gc-inhibit*)
+             (or #!+sb-thread *stop-for-gc-pending*
+                 *gc-pending*))
+    (sb!unix::receive-pending-interrupt)))
+
 ;;; These work both regardless of whether we're inside WITHOUT-GCING
 ;;; or not.
 (defun gc-on ()
   #!+sb-doc
   "Enable the garbage collector."
   (setq *gc-inhibit* nil)
-  (when (and (not *gc-inhibit*)
-             (or #!+sb-thread *stop-for-gc-pending*
-                 *gc-pending*))
-    (sb!unix::receive-pending-interrupt))
+  (maybe-handle-pending-gc)
   nil)
 
 (defun gc-off ()