X-Git-Url: http://repo.macrolet.net/gitweb/?a=blobdiff_plain;f=src%2Fcode%2Fgc.lisp;h=1acfa9cce24a680c8f9f171ff249902b3b684a54;hb=94ea2b2082deaa0331dfb66fa6af6ca12dd8dc83;hp=086d6836aad392ce2c58b54f5e7115303c5f7f34;hpb=56caa7055d1a1d228842cf4fb05dc4b53f9131b0;p=sbcl.git diff --git a/src/code/gc.lisp b/src/code/gc.lisp index 086d683..1acfa9c 100644 --- a/src/code/gc.lisp +++ b/src/code/gc.lisp @@ -17,24 +17,21 @@ sb!vm:*static-space-free-pointer*)) (eval-when (:compile-toplevel :execute) - (sb!xc:defmacro def-c-var-frob (lisp-fun c-var-name) - `(progn - #!-sb-fluid (declaim (inline ,lisp-fun)) - (defun ,lisp-fun () - (sb!alien:extern-alien ,c-var-name (sb!alien:unsigned 32)))))) + (sb!xc:defmacro def-c-var-fun (lisp-fun c-var-name) + `(defun ,lisp-fun () + (sb!alien:extern-alien ,c-var-name (sb!alien:unsigned 32))))) +#!-sb-fluid +(declaim (inline current-dynamic-space-start)) +#!+gencgc +(defun current-dynamic-space-start () sb!vm:dynamic-space-start) #!-gencgc -(progn - ;; This is called once per PROFILEd function call, so it's worth a - ;; little possible space cost to reduce its time cost. - #!-sb-fluid - (declaim (inline current-dynamic-space-start)) - (def-c-var-frob current-dynamic-space-start "current_dynamic_space")) +(def-c-var-fun current-dynamic-space-start "current_dynamic_space") #!-sb-fluid -(declaim (inline dynamic-usage)) ; to reduce PROFILEd call overhead +(declaim (inline dynamic-usage)) #!+gencgc -(def-c-var-frob dynamic-usage "bytes_allocated") +(def-c-var-fun dynamic-usage "bytes_allocated") #!-gencgc (defun dynamic-usage () (the (unsigned-byte 32) @@ -52,14 +49,14 @@ (defun control-stack-usage () #!-stack-grows-downward-not-upward (- (sb!sys:sap-int (sb!c::control-stack-pointer-sap)) - sb!vm:control-stack-start) + (sb!vm:fixnumize sb!vm:*control-stack-start*)) #!+stack-grows-downward-not-upward - (- sb!vm:control-stack-end + (- (sb!vm:fixnumize 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:binding-stack-start)) + (sb!vm:fixnumize sb!vm:*binding-stack-start*))) ;;;; ROOM @@ -69,8 +66,11 @@ (format t "Static space usage is: ~10:D bytes.~%" (static-space-usage)) (format t "Control stack usage is: ~10:D bytes.~%" (control-stack-usage)) (format t "Binding stack usage is: ~10:D bytes.~%" (binding-stack-usage)) + #!+sb-thread + (format t + "Control and binding stack usage is for the current thread only.~%") (format t "Garbage collection is currently ~:[enabled~;DISABLED~].~%" - *gc-inhibit*)) + (> *gc-inhibit* 0))) (defun room-intermediate-info () (room-minimal-info) @@ -80,10 +80,14 @@ :print-summary nil)) (defun room-maximal-info () - (room-minimal-info) - (sb!vm:memory-usage :count-spaces '(:static :dynamic)) - (sb!vm:instance-usage :dynamic :top-n 10) - (sb!vm:instance-usage :static :top-n 10)) + ;; FIXME: SB!VM:INSTANCE-USAGE calls suppressed until bug 344 is fixed + (room-intermediate-info) + ;; old way, could be restored when bug 344 fixed: + ;;x (room-minimal-info) + ;;x (sb!vm:memory-usage :count-spaces '(:static :dynamic)) + ;;x (sb!vm:instance-usage :dynamic :top-n 10) + ;;x (sb!vm:instance-usage :static :top-n 10) + ) (defun room (&optional (verbosity :default)) #!+sb-doc @@ -113,15 +117,10 @@ ;;; allocated and never freed.) (declaim (type unsigned-byte *n-bytes-freed-or-purified*)) (defvar *n-bytes-freed-or-purified* 0) -(push (lambda () - (setf *n-bytes-freed-or-purified* 0)) - ;; KLUDGE: It's probably not quite safely right either to do - ;; this in *BEFORE-SAVE-INITIALIZATIONS* (since consing, or even - ;; worse, something which depended on (GET-BYTES-CONSED), might - ;; happen after that) or in *AFTER-SAVE-INITIALIZATIONS*. But - ;; it's probably not a big problem, and there seems to be no - ;; other obvious time to do it. -- WHN 2001-07-30 - *after-save-initializations*) +(defun gc-reinit () + (gc-on) + (gc) + (setf *n-bytes-freed-or-purified* 0)) (declaim (ftype (function () unsigned-byte) get-bytes-consed)) (defun get-bytes-consed () @@ -135,65 +134,11 @@ and submit it as a patch." (+ (dynamic-usage) *n-bytes-freed-or-purified*)) -;;;; variables and constants - -;;; the minimum amount of dynamic space which must be consed before a -;;; GC will be triggered -;;; -;;; Unlike CMU CL, we don't export this variable. (There's no need to, -;;; since our BYTES-CONSED-BETWEEN-GCS function is SETFable.) -(defvar *bytes-consed-between-gcs* - #!+gencgc (* 4 (expt 10 6)) - ;; Stop-and-copy GC is really really slow when used too often. CSR - ;; reported that even on his old 64 Mb SPARC, 20 Mb is much faster - ;; than 4 Mb when rebuilding SBCL ca. 0.7.1. For modern machines - ;; with >> 128 Mb memory, the optimum could be significantly more - ;; than this, but at least 20 Mb should be better than 4 Mb. - #!-gencgc (* 20 (expt 10 6))) -(declaim (type index *bytes-consed-between-gcs*)) - ;;;; GC hooks -(defvar *before-gc-hooks* nil ; actually initialized in cold init - #!+sb-doc - "A list of functions that are called before garbage collection occurs. - The functions should take no arguments.") - -(defvar *after-gc-hooks* nil ; actually initialized in cold init - #!+sb-doc - "A list of functions that are called after garbage collection occurs. - The functions should take no arguments.") - -(defvar *gc-notify-stream* nil ; (actually initialized in cold init) - #!+sb-doc - "When non-NIL, this must be a STREAM; and the functions bound to - *GC-NOTIFY-BEFORE* and *GC-NOTIFY-AFTER* are called with the - STREAM value before and after a garbage collection occurs - respectively.") - -(defvar *gc-run-time* 0 - #!+sb-doc - "the total CPU time spent doing garbage collection (as reported by - GET-INTERNAL-RUN-TIME)") -(declaim (type index *gc-run-time*)) - -;;; a limit to help catch programs which allocate too much memory, -;;; since a hard heap overflow is so hard to recover from -;;; -;;; FIXME: Like *GC-TRIGGER*, this variable (1) should probably be -;;; denominated in a larger unit than bytes and (2) should probably be -;;; renamed so that it's clear from the name what unit it's -;;; denominated in. -(declaim (type (or unsigned-byte null) *soft-heap-limit*)) -(defvar *soft-heap-limit* - ;; As long as *GC-TRIGGER* is DECLAIMed as INDEX, we know that - ;; MOST-POSITIVE-FIXNUM is a hard limit on how much memory can be - ;; allocated. (Not necessarily *the* hard limit, which is fairly - ;; likely something like a Unix per-process limit that we don't know - ;; about, but a hard limit anyway.) And this gives us a reasonable - ;; conservative default for the soft limit... - (- most-positive-fixnum - *bytes-consed-between-gcs*)) +(defvar *after-gc-hooks* nil + "Called after each garbage collection. In a multithreaded +environment these hooks may run in any thread.") ;;;; The following specials are used to control when garbage ;;;; collection occurs. @@ -223,194 +168,83 @@ and submit it as a patch." (declaim (type (or index null) *gc-trigger*)) (defvar *gc-trigger* nil) -;;; When non-NIL, inhibits garbage collection. -(defvar *gc-inhibit*) ; initialized in cold init - -;;; This flag is used to prevent recursive entry into the garbage -;;; collector. -(defvar *already-maybe-gcing*) ; initialized in cold init - -;;; When T, indicates that the dynamic usage has exceeded the value -;;; *GC-TRIGGER*. +;;; 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 -(defun default-gc-notify-before (notify-stream bytes-in-use) - (declare (type stream notify-stream)) - (format - notify-stream - "~&; GC is beginning with ~:D bytes in use at internal runtime ~:D.~%" - bytes-in-use - (get-internal-run-time)) - (finish-output notify-stream)) -(defparameter *gc-notify-before* #'default-gc-notify-before - #!+sb-doc - "The function bound to this variable is invoked before GC'ing (unless - *GC-NOTIFY-STREAM* is NIL) with the value of *GC-NOTIFY-STREAM* and - current amount of dynamic usage (in bytes). It should notify the - user that the system is going to GC.") - -(defun default-gc-notify-after (notify-stream - bytes-retained - bytes-freed - new-trigger) - (declare (type stream notify-stream)) - (format notify-stream - "~&; GC has finished with ~:D bytes in use (~:D bytes freed)~@ - ; at internal runtime ~:D. The new GC trigger is ~:D bytes.~%" - bytes-retained - bytes-freed - (get-internal-run-time) - new-trigger) - (finish-output notify-stream)) -(defparameter *gc-notify-after* #'default-gc-notify-after - #!+sb-doc - "The function bound to this variable is invoked after GC'ing with the -value of *GC-NOTIFY-STREAM*, the amount of dynamic usage (in bytes) now -free, the number of bytes freed by the GC, and the new GC trigger -threshold; or if *GC-NOTIFY-STREAM* is NIL, it's not invoked. The -function should notify the user that the system has finished GC'ing.") - ;;;; internal GC (sb!alien:define-alien-routine collect-garbage sb!alien:int (#!+gencgc last-gen #!-gencgc ignore sb!alien:int)) -(sb!alien:define-alien-routine set-auto-gc-trigger sb!alien:void - (dynamic-usage sb!alien:unsigned-long)) - -(sb!alien:define-alien-routine clear-auto-gc-trigger sb!alien:void) +#!+sb-thread +(progn + (sb!alien:define-alien-routine gc-stop-the-world sb!alien:void) + (sb!alien:define-alien-routine gc-start-the-world sb!alien:void)) +#!-sb-thread +(progn + (defun gc-stop-the-world ()) + (defun gc-start-the-world ())) -;;; This variable contains the function that does the real GC. This is -;;; for low-level GC experimentation. Do not touch it if you do not -;;; know what you are doing. -(defvar *internal-gc* #'collect-garbage) ;;;; SUB-GC -;;; This is used to carefully invoke hooks. -(eval-when (:compile-toplevel :execute) - (sb!xc:defmacro carefully-funcall (function &rest args) - `(handler-case (funcall ,function ,@args) - (error (cond) - (warn "(FUNCALL ~S~{ ~S~}) lost:~%~A" ',function ',args cond) - nil)))) - -;;; SUB-GC decides when and if to do a garbage collection. The FORCE-P -;;; flags controls whether a GC should occur even if the dynamic usage -;;; is not greater than *GC-TRIGGER*. +;;; SUB-GC does a garbage collection. This is called from three places: +;;; (1) The C runtime will call here when it detects that we've consed +;;; enough to exceed the gc trigger threshold. This is done in +;;; alloc() for gencgc or interrupt_maybe_gc() for cheneygc +;;; (2) The user may request a collection using GC, below +;;; (3) At the end of a WITHOUT-GCING section, we are called if +;;; *NEED-TO-COLLECT-GARBAGE* is true ;;; +;;; This is different from the behaviour in 0.7 and earlier: it no +;;; longer decides whether to GC based on thresholds. If you call +;;; SUB-GC you will definitely get a GC either now or when the +;;; WITHOUT-GCING is over + ;;; For GENCGC all generations < GEN will be GC'ed. -(defun sub-gc (&key force-p (gen 0)) - (/show0 "entering SUB-GC") - (unless *already-maybe-gcing* - (let* ((*already-maybe-gcing* t) - (start-time (get-internal-run-time)) - (pre-gc-dynamic-usage (dynamic-usage)) - ;; Currently we only check *SOFT-HEAP-LIMIT* at GC time, - ;; not for every allocation. That makes it cheap to do, - ;; even if it is a little ugly. - (soft-heap-limit-exceeded? (and *soft-heap-limit* - (> pre-gc-dynamic-usage - *soft-heap-limit*))) - (*soft-heap-limit* (if soft-heap-limit-exceeded? - (+ pre-gc-dynamic-usage - *bytes-consed-between-gcs*) - *soft-heap-limit*))) - (when soft-heap-limit-exceeded? - (cerror "Continue with GC." - "soft heap limit exceeded (temporary new limit=~W)" - *soft-heap-limit*)) - (when (and *gc-trigger* (> pre-gc-dynamic-usage *gc-trigger*)) - (setf *need-to-collect-garbage* t)) - (when (or force-p - (and *need-to-collect-garbage* (not *gc-inhibit*))) - ;; KLUDGE: Wow, we really mask interrupts all the time we're - ;; collecting garbage? That seems like a long time.. -- WHN 19991129 - (without-interrupts - ;; FIXME: We probably shouldn't do this evil thing to - ;; *STANDARD-OUTPUT* in a binding which is wrapped around - ;; calls to user-settable GC hook functions. - (let ((*standard-output* *terminal-io*)) - (when *gc-notify-stream* - (if (streamp *gc-notify-stream*) - (carefully-funcall *gc-notify-before* - *gc-notify-stream* - pre-gc-dynamic-usage) - (warn - "*GC-NOTIFY-STREAM* is set, but not a STREAM -- ignored."))) - (dolist (hook *before-gc-hooks*) - (carefully-funcall hook)) - (when *gc-trigger* - (clear-auto-gc-trigger)) - (let* (;; We do DYNAMIC-USAGE once more here in order to - ;; get a more accurate measurement of the space - ;; actually freed, since the messing around, e.g. - ;; GC-notify stuff, since the DYNAMIC-USAGE which - ;; triggered GC could've done a fair amount of - ;; consing.) - (pre-internal-gc-dynamic-usage (dynamic-usage)) - (ignore-me (funcall *internal-gc* gen)) - (post-gc-dynamic-usage (dynamic-usage)) - (n-bytes-freed (- pre-internal-gc-dynamic-usage - post-gc-dynamic-usage)) - ;; In sbcl-0.6.12.39, the raw N-BYTES-FREED from - ;; GENCGC could sometimes be substantially negative - ;; (e.g. -5872). I haven't looked into what causes - ;; that, but I suspect it has to do with - ;; fluctuating inefficiency in the way that the - ;; GENCGC packs things into page boundaries. - ;; Bumping the raw result up to 0 is a little ugly, - ;; but shouldn't be a problem, and it's even - ;; possible to sort of justify it: the packing - ;; inefficiency which has caused (DYNAMIC-USAGE) to - ;; grow is effectively consing, or at least - ;; overhead of consing, so it's sort of correct to - ;; add it to the running total of consing. ("Man - ;; isn't a rational animal, he's a rationalizing - ;; animal.":-) -- WHN 2001-06-23 - (eff-n-bytes-freed (max 0 n-bytes-freed))) - (declare (ignore ignore-me)) - (/show0 "got (DYNAMIC-USAGE) and EFF-N-BYTES-FREED") - (incf *n-bytes-freed-or-purified* - eff-n-bytes-freed) - (/show0 "clearing *NEED-TO-COLLECT-GARBAGE*") - (setf *need-to-collect-garbage* nil) - (/show0 "calculating NEW-GC-TRIGGER") - (let ((new-gc-trigger (+ post-gc-dynamic-usage - *bytes-consed-between-gcs*))) - (/show0 "setting *GC-TRIGGER*") - (setf *gc-trigger* new-gc-trigger)) - (/show0 "calling SET-AUTO-GC-TRIGGER") - (set-auto-gc-trigger *gc-trigger*) - (dolist (hook *after-gc-hooks*) - (/show0 "doing a hook from *AFTER-GC--HOOKS*") - ;; FIXME: This hook should be called with the same - ;; kind of information as *GC-NOTIFY-AFTER*. In - ;; particular, it would be nice for the hook function - ;; to be able to adjust *GC-TRIGGER* intelligently to - ;; e.g. 108% of total memory usage. - (carefully-funcall hook)) - (when *gc-notify-stream* - (if (streamp *gc-notify-stream*) - (carefully-funcall *gc-notify-after* - *gc-notify-stream* - post-gc-dynamic-usage - eff-n-bytes-freed - *gc-trigger*) - (warn - "*GC-NOTIFY-STREAM* is set, but not a stream -- ignored."))))) - (scrub-control-stack))) ;XXX again? we did this from C ... - (incf *gc-run-time* (- (get-internal-run-time) - start-time)))) - ;; FIXME: should probably return (VALUES), here and in RETURN-FROM - nil) -;;; This routine is called by the allocation miscops to decide whether -;;; a GC should occur. The argument, OBJECT, is the newly allocated -;;; object which must be returned to the caller. -(defun maybe-gc (&optional object) - (sub-gc) - object) +(defvar *already-in-gc* + (sb!thread:make-mutex :name "GC lock") "ID of thread running SUB-GC") + +(defun sub-gc (&key (gen 0)) + (unless (eq sb!thread:*current-thread* + (sb!thread::mutex-value *already-in-gc*)) + ;; With gencgc, unless *NEED-TO-COLLECT-GARBAGE* every allocation + ;; in this function triggers another gc, potentially exceeding + ;; maximum interrupt nesting. + (setf *need-to-collect-garbage* t) + (when (zerop *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 *need-to-collect-garbage* 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))))))) ;;; This is the user-advertised garbage collection function. (defun gc (&key (gen 0) (full nil) &allow-other-keys) @@ -420,7 +254,16 @@ function should notify the user that the system has finished GC'ing.") #!+(and sb-doc (not gencgc)) "Initiate a garbage collection. GEN may be provided for compatibility with generational garbage collectors, but is ignored in this implementation." - (sub-gc :force-p t :gen (if full 6 gen))) + (sub-gc :gen (if full 6 gen))) + +(defun unsafe-clear-roots () + ;; KLUDGE: Do things in an attempt to get rid of extra roots. Unsafe + ;; as having these cons more then we have space left leads to huge + ;; badness. + (scrub-control-stack) + ;; FIXME: CTYPE-OF-CACHE-CLEAR isn't thread-safe. + #!-sb-thread + (ctype-of-cache-clear)) ;;;; auxiliary functions @@ -429,30 +272,22 @@ function should notify the user that the system has finished GC'ing.") #!+sb-doc "Return the amount of memory that will be allocated before the next garbage collection is initiated. This can be set with SETF." - *bytes-consed-between-gcs*) + (sb!alien:extern-alien "bytes_consed_between_gcs" + (sb!alien:unsigned 32))) + (defun (setf bytes-consed-between-gcs) (val) - ;; FIXME: Shouldn't this (and the DECLAIM for the underlying variable) - ;; be for a strictly positive number type, e.g. - ;; (AND (INTEGER 1) FIXNUM)? (declare (type index val)) - (let ((old *bytes-consed-between-gcs*)) - (setf *bytes-consed-between-gcs* val) - (when *gc-trigger* - (setf *gc-trigger* (+ *gc-trigger* (- val old))) - (cond ((<= (dynamic-usage) *gc-trigger*) - (clear-auto-gc-trigger) - (set-auto-gc-trigger *gc-trigger*)) - (t - ;; FIXME: If SCRUB-CONTROL-STACK is required here, why - ;; isn't it built into SUB-GC? And *is* it required here? - (sb!sys:scrub-control-stack) - (sub-gc))))) - val) + (setf (sb!alien:extern-alien "bytes_consed_between_gcs" + (sb!alien:unsigned 32)) + val)) +;;; FIXME: Aren't these utterly wrong if called inside WITHOUT-GCING? +;;; Unless something that works there too can be deviced this fact +;;; should be documented. (defun gc-on () #!+sb-doc "Enable the garbage collector." - (setq *gc-inhibit* nil) + (setq *gc-inhibit* 0) (when *need-to-collect-garbage* (sub-gc)) nil) @@ -460,13 +295,5 @@ function should notify the user that the system has finished GC'ing.") (defun gc-off () #!+sb-doc "Disable the garbage collector." - (setq *gc-inhibit* t) + (setq *gc-inhibit* 1) nil) - -;;;; initialization stuff - -(defun gc-reinit () - (when *gc-trigger* - (if (< *gc-trigger* (dynamic-usage)) - (sub-gc) - (set-auto-gc-trigger *gc-trigger*))))