X-Git-Url: http://repo.macrolet.net/gitweb/?a=blobdiff_plain;ds=sidebyside;f=src%2Fcode%2Fgc.lisp;h=e6abbb13ed4fd3990c5a2da63be8d5f4b242bada;hb=83097ed630d4efdb79bd0bc91f21014f4365f008;hp=39d59a63ab097d8d02686bc62fcb386ef786ed1f;hpb=02c9007b4ca5753406f60019f4fe5e5f8392541a;p=sbcl.git diff --git a/src/code/gc.lisp b/src/code/gc.lisp index 39d59a6..e6abbb1 100644 --- a/src/code/gc.lisp +++ b/src/code/gc.lisp @@ -14,27 +14,24 @@ ;;;; DYNAMIC-USAGE and friends (declaim (special sb!vm:*read-only-space-free-pointer* - sb!vm:*static-space-free-pointer*)) + 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: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*)))) ;;;; ROOM @@ -70,23 +67,27 @@ (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 + "Control and binding stack usage is for the current thread only.~%") (format t "Garbage collection is currently ~:[enabled~;DISABLED~].~%" - (> *gc-inhibit* 0))) + *gc-inhibit*)) (defun room-intermediate-info () (room-minimal-info) (sb!vm:memory-usage :count-spaces '(:dynamic) - :print-spaces t - :cutoff 0.05f0 - :print-summary nil)) + :print-spaces t + :cutoff 0.05f0 + :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 @@ -116,17 +117,15 @@ ;;; 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*) - -(declaim (ftype (function () unsigned-byte) get-bytes-consed)) +(defun gc-reinit () + (gc-on) + (gc) + (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 (sfunction () unsigned-byte) get-bytes-consed)) (defun get-bytes-consed () #!+sb-doc "Return the number of bytes consed since the program began. Typically @@ -138,122 +137,35 @@ 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 + "Called after each garbage collection, except for garbage collections +triggered during thread exits. In a multithreaded environment these hooks may +run in any thread.") -(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*)) - -;;;; The following specials are used to control when garbage -;;;; collection occurs. - -;;; When the dynamic usage increases beyond this amount, the system -;;; notes that a garbage collection needs to occur by setting -;;; *NEED-TO-COLLECT-GARBAGE* to T. It starts out as NIL meaning -;;; nobody has figured out what it should be yet. -;;; -;;; FIXME: *GC-TRIGGER* seems to be denominated in bytes, not words. -;;; And limiting it to INDEX is fairly reasonable in order to avoid -;;; bignum arithmetic on every allocation, and to minimize the need -;;; for thought about weird gotchas of the GC-control mechanism itself -;;; consing as it operates. But as of sbcl-0.7.5, 512Mbytes of memory -;;; costs $54.95 at Fry's in Dallas but cheap consumer 64-bit machines -;;; are still over the horizon, so gratuitously limiting our heap size -;;; to FIXNUM bytes seems fairly stupid. It'd be reasonable to -;;; (1) allow arbitrary UNSIGNED-BYTE values of *GC-TRIGGER*, or -;;; (2) redenominate this variable in words instead of bytes, postponing -;;; the problem to heaps which exceed 50% of the machine's address -;;; space, or even -;;; (3) redemoninate this variable in CONS-sized two-word units, -;;; allowing it to cover the entire memory space at the price of -;;; possible loss of clarity. -;;; (And whatever is done, it'd also be good to rename the variable so -;;; that it's clear what unit it's denominated in.) -(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 ;;;; 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 -(def-c-var-frob gc-thread-pid "gc_thread_pid") -#!+sb-thread -(defun other-thread-collect-garbage (gen) - (setf (sb!alien:extern-alien "maybe_gc_pending" (sb!alien:unsigned 32)) - (1+ gen)) - (sb!unix:unix-kill (gc-thread-pid) :SIGALRM)) - -;;; 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* - #!+sb-thread #'other-thread-collect-garbage - #!-sb-thread #'collect-garbage) - +(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 ())) + ;;;; 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 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 +;;; (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 @@ -265,47 +177,78 @@ and submit it as a patch." ;;; For GENCGC all generations < GEN will be GC'ed. -(defvar *gc-mutex* (sb!thread:make-mutex :name "GC Mutex")) - -(defun sub-gc (&key (gen 0)) - (when (sb!thread::mutex-value *gc-mutex*) (return-from sub-gc nil)) - (sb!thread:with-mutex (*gc-mutex* :wait-p nil) - (let* ((start-time (get-internal-run-time))) - (setf *need-to-collect-garbage* t) - (when (zerop *gc-inhibit*) - (without-interrupts - (dolist (hook *before-gc-hooks*) (carefully-funcall hook)) - (when *gc-trigger* - (clear-auto-gc-trigger)) - (let* ((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)) - ;; the raw N-BYTES-FREED from GENCGC can sometimes be - ;; substantially negative (e.g. -5872). This is - ;; probably due to fluctuating inefficiency in the way - ;; that the GENCGC packs things into page boundaries. - ;; We bump the raw result up to 0: the space is - ;; allocated even if unusable, so should be counted - ;; for deciding when we've allocated enough to GC - ;; next. ("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)) - (incf *n-bytes-freed-or-purified* eff-n-bytes-freed) - (setf *need-to-collect-garbage* nil) - (setf *gc-trigger* (+ post-gc-dynamic-usage - *bytes-consed-between-gcs*)) - (set-auto-gc-trigger *gc-trigger*) - (dolist (hook *after-gc-hooks*) - (carefully-funcall hook)))) - (scrub-control-stack)) ;XXX again? we did this from C ... - (incf *gc-run-time* (- (get-internal-run-time) start-time)))) - nil) - +(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*)) + ;; With gencgc, unless *GC-PENDING* every allocation in this + ;; function triggers another gc, potentially exceeding maximum + ;; 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) @@ -315,7 +258,19 @@ and submit it as a patch." #!+(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 :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) + ;; 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)) ;;;; auxiliary functions @@ -324,44 +279,33 @@ and submit it as a patch." #!+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)) + +(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* 0) - (when *need-to-collect-garbage* - (sub-gc)) + (setq *gc-inhibit* nil) + (maybe-handle-pending-gc) nil) (defun gc-off () #!+sb-doc "Disable the garbage collector." - (setq *gc-inhibit* 1) + (setq *gc-inhibit* t) nil) - -;;;; initialization stuff - -(defun gc-reinit () - (when *gc-trigger* - (if (< *gc-trigger* (dynamic-usage)) - (sub-gc) - (set-auto-gc-trigger *gc-trigger*))))