1 ;;;; garbage collection and allocation-related code
3 ;;;; This software is part of the SBCL system. See the README file for
6 ;;;; This software is derived from the CMU CL system, which was
7 ;;;; written at Carnegie Mellon University and released into the
8 ;;;; public domain. The software is in the public domain and is
9 ;;;; provided with absolutely no warranty. See the COPYING and CREDITS
10 ;;;; files for more information.
12 (in-package "SB!KERNEL")
17 ;;;; DYNAMIC-USAGE and friends
19 (declaim (special sb!vm:*read-only-space-free-pointer*
20 sb!vm:*static-space-free-pointer*))
22 (eval-when (:compile-toplevel :execute)
23 (sb!xc:defmacro def-c-var-frob (lisp-fun c-var-name)
25 #!-sb-fluid (declaim (inline ,lisp-fun))
27 (sb!alien:extern-alien ,c-var-name (sb!alien:unsigned 32))))))
29 #!-sb-fluid (declaim (inline dynamic-usage))
30 (def-c-var-frob dynamic-usage "bytes_allocated")
32 (defun static-space-usage ()
33 (- (* sb!vm:*static-space-free-pointer* sb!vm:word-bytes)
34 sb!vm:static-space-start))
36 (defun read-only-space-usage ()
37 (- (* sb!vm::*read-only-space-free-pointer* sb!vm:word-bytes)
38 sb!vm:read-only-space-start))
40 (defun control-stack-usage ()
41 #!-x86 (- (sb!sys:sap-int (sb!c::control-stack-pointer-sap))
43 #!+x86 (- control-stack-end
44 (sb!sys:sap-int (sb!c::control-stack-pointer-sap))))
46 (defun binding-stack-usage ()
47 (- (sb!sys:sap-int (sb!c::binding-stack-pointer-sap))
48 sb!vm:binding-stack-start))
52 (defun room-minimal-info ()
53 (format t "Dynamic space usage is: ~10:D bytes.~%" (dynamic-usage))
54 (format t "Read-only space usage is: ~10:D bytes.~%" (read-only-space-usage))
55 (format t "Static space usage is: ~10:D bytes.~%" (static-space-usage))
56 (format t "Control stack usage is: ~10:D bytes.~%" (control-stack-usage))
57 (format t "Binding stack usage is: ~10:D bytes.~%" (binding-stack-usage))
58 (format t "Garbage collection is currently ~:[enabled~;DISABLED~].~%"
61 (defun room-intermediate-info ()
63 (sb!vm:memory-usage :count-spaces '(:dynamic)
68 (defun room-maximal-info ()
70 (sb!vm:memory-usage :count-spaces '(:static :dynamic))
71 (sb!vm:instance-usage :dynamic :top-n 10)
72 (sb!vm:instance-usage :static :top-n 10))
74 (defun room (&optional (verbosity :default))
76 "Prints to *STANDARD-OUTPUT* information about the state of internal
77 storage and its management. The optional argument controls the
78 verbosity of ROOM. If it is T, ROOM prints out a maximal amount of
79 information. If it is NIL, ROOM prints out a minimal amount of
80 information. If it is :DEFAULT or it is not supplied, ROOM prints out
81 an intermediate amount of information. See also VM:MEMORY-USAGE and
82 VM:INSTANCE-USAGE for finer report control."
90 (room-intermediate-info)))
96 (defvar *last-bytes-in-use* nil)
97 (defvar *total-bytes-consed* 0)
98 (declaim (type (or index null) *last-bytes-in-use*))
99 (declaim (type integer *total-bytes-consed*))
101 (declaim (ftype (function () unsigned-byte) get-bytes-consed))
102 (defun get-bytes-consed ()
104 "Returns the number of bytes consed since the first time this function
105 was called. The first time it is called, it returns zero."
106 (declare (optimize (speed 3) (safety 0)))
107 (cond ((null *last-bytes-in-use*)
108 (setq *last-bytes-in-use* (dynamic-usage))
109 (setq *total-bytes-consed* 0))
111 (let ((bytes (dynamic-usage)))
112 (incf *total-bytes-consed*
113 (the index (- bytes *last-bytes-in-use*)))
114 (setq *last-bytes-in-use* bytes))))
115 *total-bytes-consed*)
117 ;;;; variables and constants
119 ;;; the default value of *BYTES-CONSED-BETWEEN-GCS* and *GC-TRIGGER*
120 (defconstant default-bytes-consed-between-gcs 2000000)
122 ;;; This variable is the user-settable variable that specifies the
123 ;;; minimum amount of dynamic space which must be consed before a GC
124 ;;; will be triggered.
126 ;;; Unlike CMU CL, we don't export this variable. (There's no need to, since
127 ;;; the BYTES-CONSED-BETWEEN-GCS function is SETFable.)
128 (defvar *bytes-consed-between-gcs* default-bytes-consed-between-gcs
130 "This number specifies the minimum number of bytes of dynamic space
131 that must be consed before the next GC will occur.")
132 (declaim (type index *bytes-consed-between-gcs*))
136 ;;; These variables are a list of functions which are run before and
137 ;;; after garbage collection occurs.
138 (defvar *before-gc-hooks* nil ; actually initialized in cold init
140 "A list of functions that are called before garbage collection occurs.
141 The functions should take no arguments.")
142 (defvar *after-gc-hooks* nil ; actually initialized in cold init
144 "A list of functions that are called after garbage collection occurs.
145 The functions should take no arguments.")
147 ;;; This hook is invoked whenever SUB-GC intends to GC (unless the GC
148 ;;; was explicitly forced by calling SB!EXT:GC). If the hook function
149 ;;; returns NIL then the GC procedes; otherwise, the GC is inhibited and
150 ;;; *GC-INHIBIT* and *NEED-TO-COLLECT-GARBAGE* are left bound to T.
151 ;;; Presumably someone will call GC-ON later to collect the garbage.
152 (defvar *gc-inhibit-hook* nil
154 "Should be bound to a function or NIL. If it is a function, this
155 function should take one argument, the current amount of dynamic
156 usage. The function should return NIL if garbage collection should
157 continue and non-NIL if it should be inhibited. Use with caution.")
159 (defvar *gc-verbose* nil ; (actually initialized in cold init)
161 "Should low-level GC functions produce verbose diagnostic output?")
163 (defvar *gc-notify-stream* nil ; (actually initialized in cold init)
165 "When non-NIL, this must be a STREAM; and the functions bound to
166 *GC-NOTIFY-BEFORE* and *GC-NOTIFY-AFTER* are called with the
167 STREAM value before and after a garbage collection occurs
170 (defvar *gc-run-time* 0
172 "The total CPU time spent doing garbage collection (as reported by
173 GET-INTERNAL-RUN-TIME.)")
175 (declaim (type index *gc-run-time*))
177 ;;; Internal trigger. When the dynamic usage increases beyond this
178 ;;; amount, the system notes that a garbage collection needs to occur by
179 ;;; setting *NEED-TO-COLLECT-GARBAGE* to T. It starts out as NIL meaning
180 ;;; nobody has figured out what it should be yet.
181 (defvar *gc-trigger* nil)
183 (declaim (type (or index null) *gc-trigger*))
185 ;;; On the RT, we store the GC trigger in a ``static'' symbol instead of
186 ;;; letting magic C code handle it. It gets initialized by the startup
187 ;;; code. The X86 port defines this here because it uses the `ibmrt'
188 ;;; feature in the C code for allocation and binding stack access and
189 ;;; a lot of stuff wants this INTERNAL_GC_TRIGGER available as well.
191 (defvar sb!vm::*internal-gc-trigger*)
193 ;;;; The following specials are used to control when garbage collection
196 ;;; When non-NIL, inhibits garbage collection.
197 (defvar *gc-inhibit*) ; initialized in cold init
199 ;;; This flag is used to prevent recursive entry into the garbage
201 (defvar *already-maybe-gcing*) ; initialized in cold init
203 ;;; When T, indicates that the dynamic usage has exceeded the value
205 (defvar *need-to-collect-garbage* nil) ; initialized in cold init
207 (defun default-gc-notify-before (notify-stream bytes-in-use)
208 (declare (type stream notify-stream))
209 (format notify-stream
210 "~&; GC is beginning with ~:D bytes in use.~%"
212 (finish-output notify-stream))
213 (defparameter *gc-notify-before* #'default-gc-notify-before
215 "This function bound to this variable is invoked before GC'ing (unless
216 *GC-NOTIFY-STREAM* is NIL) with the value of *GC-NOTIFY-STREAM* and
217 current amount of dynamic usage (in bytes). It should notify the
218 user that the system is going to GC.")
220 (defun default-gc-notify-after (notify-stream
224 (declare (type stream notify-stream))
225 (format notify-stream
226 "~&; GC has finished with ~:D bytes in use (~:D bytes freed).~%"
229 (format notify-stream
230 "~&; The new GC trigger is ~:D bytes.~%"
232 (finish-output notify-stream))
233 (defparameter *gc-notify-after* #'default-gc-notify-after
235 "The function bound to this variable is invoked after GC'ing (unless
236 *GC-VERBOSE* is NIL) with the value of *GC-NOTIFY-STREAM*,
237 the amount of dynamic usage (in bytes) now free, the number of
238 bytes freed by the GC, and the new GC trigger threshold. The function
239 should notify the user that the system has finished GC'ing.")
243 (sb!alien:def-alien-routine collect-garbage sb!c-call:int
244 #!+gencgc (last-gen sb!c-call:int))
246 (sb!alien:def-alien-routine set-auto-gc-trigger sb!c-call:void
247 (dynamic-usage sb!c-call:unsigned-long))
249 (sb!alien:def-alien-routine clear-auto-gc-trigger sb!c-call:void)
251 ;;; This variable contains the function that does the real GC. This is
252 ;;; for low-level GC experimentation. Do not touch it if you do not
253 ;;; know what you are doing.
254 (defvar *internal-gc* #'collect-garbage)
258 ;;; Used to carefully invoke hooks.
259 (eval-when (:compile-toplevel :execute)
260 (sb!xc:defmacro carefully-funcall (function &rest args)
261 `(handler-case (funcall ,function ,@args)
263 (warn "(FUNCALL ~S~{ ~S~}) lost:~%~A" ',function ',args cond)
266 ;;; SUB-GC decides when and if to do a garbage collection. The
267 ;;; VERBOSE-P flag controls whether or not the notify functions are
268 ;;; called. The FORCE-P flags controls if a GC should occur even if
269 ;;; the dynamic usage is not greater than *GC-TRIGGER*.
271 ;;; For GENCGC all generations < GEN will be GC'ed.
273 ;;; FIXME: The VERBOSE-P stuff is no longer used.
274 (defun sub-gc (&key (verbose-p *gc-verbose*) force-p #!+gencgc (gen 0))
275 (/show0 "entering SUB-GC")
276 (unless *already-maybe-gcing*
277 (/show0 "not *ALREADY-MAYBE-GCING*")
278 (let* ((*already-maybe-gcing* t)
279 (start-time (get-internal-run-time))
280 (pre-gc-dyn-usage (dynamic-usage)))
281 (unless (integerp (symbol-value '*bytes-consed-between-gcs*))
282 ;; The noise w/ symbol-value above is to keep the compiler
283 ;; from optimizing the test away because of the type declaim
284 ;; for *bytes-consed-between-gcs*.
286 ;; FIXME: I'm inclined either to get rid of the DECLAIM or to
287 ;; trust it, instead of doing this weird hack. It's not
288 ;; particularly trustable, since (SETF
289 ;; *BYTES-CONSED-BETWEEN-GCS* 'SEVEN) works. But it's also not
290 ;; very nice to have the type of the variable specified in two
291 ;; places which can (and in CMU CL 2.4.8 did, INTEGER vs.
292 ;; INDEX) drift apart. So perhaps we should just add a note to
293 ;; the variable documentation for *BYTES-CONSED-BETWEEN-GCS*
294 ;; that it must be an INDEX, and remove the DECLAIM. Or we
295 ;; could make a SETFable (BYTES-CONSED-BETWEEN-GCS) function
296 ;; and enforce the typing that way. And in fact the SETFable
297 ;; function already exists, so all we need do is make the
298 ;; variable private, and then we can trust the DECLAIM.
299 (warn "The value of *BYTES-CONSED-BETWEEN-GCS*, ~S, is not an ~
300 integer. Resetting it to ~D."
301 *bytes-consed-between-gcs*
302 default-bytes-consed-between-gcs)
303 (setf *bytes-consed-between-gcs* default-bytes-consed-between-gcs))
304 (when (and *gc-trigger* (> pre-gc-dyn-usage *gc-trigger*))
305 (/show0 "setting *NEED-TO-COLLECT-GARBAGE* to T")
306 (setf *need-to-collect-garbage* t))
308 (and *need-to-collect-garbage* (not *gc-inhibit*)))
309 (/show0 "Evidently we ought to collect garbage..")
310 (when (and (not force-p)
312 (carefully-funcall *gc-inhibit-hook* pre-gc-dyn-usage))
313 (/show0 "..but we're inhibited.")
314 (setf *gc-inhibit* t)
315 (return-from sub-gc nil))
316 ;; KLUDGE: Wow, we really mask interrupts all the time we're
317 ;; collecting garbage? That seems like a long time.. -- WHN 19991129
319 ;; FIXME: We probably shouldn't do this evil thing to
320 ;; *STANDARD-OUTPUT* in a binding which is wrapped around
321 ;; calls to user-settable GC hook functions.
322 (let ((*standard-output* *terminal-io*))
323 (when *gc-notify-stream*
324 (/show0 "doing the *GC-NOTIFY-BEFORE* thing")
325 (if (streamp *gc-notify-stream*)
326 (carefully-funcall *gc-notify-before*
330 "*GC-NOTIFY-STREAM* is set, but not a STREAM -- ignored.")))
331 (dolist (hook *before-gc-hooks*)
332 (/show0 "doing a hook from *BEFORE-GC-HOOKS*")
333 (carefully-funcall hook))
335 (clear-auto-gc-trigger))
336 (/show0 "FUNCALLing *INTERNAL-GC*, one way or another")
337 #!-gencgc (funcall *internal-gc*)
338 ;; FIXME: This EQ test is pretty gross. Among its other
339 ;; nastinesses, it looks as though it could break if we
340 ;; recompile COLLECT-GARBAGE.
341 #!+gencgc (if (eq *internal-gc* #'collect-garbage)
342 (funcall *internal-gc* gen)
343 (funcall *internal-gc*))
344 (/show0 "back from FUNCALL to *INTERNAL-GC*")
345 (let* ((post-gc-dyn-usage (dynamic-usage))
346 (bytes-freed (- pre-gc-dyn-usage post-gc-dyn-usage)))
347 (when *last-bytes-in-use*
348 (incf *total-bytes-consed*
349 (- pre-gc-dyn-usage *last-bytes-in-use*))
350 (setq *last-bytes-in-use* post-gc-dyn-usage))
351 (setf *need-to-collect-garbage* nil)
352 (let ((new-gc-trigger (+ post-gc-dyn-usage
353 *bytes-consed-between-gcs*)))
354 (setf *gc-trigger* new-gc-trigger))
355 (set-auto-gc-trigger *gc-trigger*)
356 (dolist (hook *after-gc-hooks*)
357 (/show0 "doing a hook from *AFTER-GC--HOOKS*")
358 ;; FIXME: This hook should be called with the
359 ;; same kind of information as *GC-NOTIFY-AFTER*.
360 ;; In particular, it would be nice for the
361 ;; hook function to be able to adjust *GC-TRIGGER*
362 ;; intelligently to e.g. 108% of total memory usage.
363 (carefully-funcall hook))
364 (when *gc-notify-stream*
365 (/show0 "doing the *GC-NOTIFY-AFTER* thing")
366 (if (streamp *gc-notify-stream*)
367 (carefully-funcall *gc-notify-after*
373 "*GC-NOTIFY-STREAM* is set, but not a stream -- ignored.")))))
374 (/show0 "scrubbing control stack")
375 (scrub-control-stack)))
376 (/show0 "updating *GC-RUN-TIME*")
377 (incf *gc-run-time* (- (get-internal-run-time)
379 ;; FIXME: should probably return (VALUES), here and in RETURN-FROM
380 (/show "returning from tail of SUB-GC")
383 ;;; This routine is called by the allocation miscops to decide whether
384 ;;; a GC should occur. The argument, OBJECT, is the newly allocated
385 ;;; object which must be returned to the caller.
386 (defun maybe-gc (&optional object)
390 ;;; This is the user-advertised garbage collection function.
392 ;;; KLUDGE: GC shouldn't have different parameters depending on what
393 ;;; garbage collector we use. -- WHN 19991020
395 (defun gc (&optional (verbose-p *gc-verbose*))
397 "Initiates a garbage collection. VERBOSE-P controls
398 whether or not GC statistics are printed."
399 (sub-gc :verbose-p verbose-p :force-p t))
401 (defun gc (&key (verbose *gc-verbose*) (gen 0) (full nil))
403 "Initiates a garbage collection. VERBOSE controls whether or not GC
404 statistics are printed. GEN controls the number of generations to garbage
406 ;; FIXME: The bare 6 here (corresponding to a bare 6 in
407 ;; the gencgc.c sources) is nasty.
408 (sub-gc :verbose-p verbose :force-p t :gen (if full 6 gen)))
410 ;;;; auxiliary functions
412 (defun bytes-consed-between-gcs ()
414 "Return the amount of memory that will be allocated before the next garbage
415 collection is initiated. This can be set with SETF."
416 *bytes-consed-between-gcs*)
417 (defun (setf bytes-consed-between-gcs) (val)
418 ;; FIXME: Shouldn't this (and the DECLAIM for the underlying variable)
419 ;; be for a strictly positive number type, e.g.
420 ;; (AND (INTEGER 1) FIXNUM)?
421 (declare (type index val))
422 (let ((old *bytes-consed-between-gcs*))
423 (setf *bytes-consed-between-gcs* val)
425 (setf *gc-trigger* (+ *gc-trigger* (- val old)))
426 (cond ((<= (dynamic-usage) *gc-trigger*)
427 (clear-auto-gc-trigger)
428 (set-auto-gc-trigger *gc-trigger*))
430 (sb!sys:scrub-control-stack)
436 "Enables the garbage collector."
437 (setq *gc-inhibit* nil)
438 (when *need-to-collect-garbage*
444 "Disables the garbage collector."
445 (setq *gc-inhibit* t)
448 ;;;; initialization stuff
450 (defun gc-cold-init-or-reinit ()
452 (if (< *gc-trigger* (dynamic-usage))
454 (set-auto-gc-trigger *gc-trigger*))))