X-Git-Url: http://repo.macrolet.net/gitweb/?a=blobdiff_plain;f=src%2Fcode%2Fgc.lisp;h=f3dacccbcd22e1dba6d3afb5b8a3438e2f19182b;hb=ebdf67c1da1884d5def43062a97174f28fcb6a2c;hp=e9e1eb189dacbd2be21061c1de89f046f468897d;hpb=c81c32ef8a737b0cc61d3c0c6a137cab39baac73;p=sbcl.git diff --git a/src/code/gc.lisp b/src/code/gc.lisp index e9e1eb1..f3daccc 100644 --- a/src/code/gc.lisp +++ b/src/code/gc.lisp @@ -33,9 +33,9 @@ #!-sb-fluid (declaim (inline dynamic-usage)) ; to reduce PROFILEd call overhead -#!+(or cgc gencgc) +#!+gencgc (def-c-var-frob dynamic-usage "bytes_allocated") -#!-(or cgc gencgc) +#!-gencgc (defun dynamic-usage () (the (unsigned-byte 32) (- (sb!sys:sap-int (sb!c::dynamic-space-free-pointer)) @@ -52,14 +52,14 @@ (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 +69,11 @@ (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) @@ -135,23 +138,6 @@ 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 @@ -177,83 +163,50 @@ and submit it as a patch." 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 -(declaim (type (or unsigned-byte null) *soft-heap-limit*)) -(defvar *soft-heap-limit* nil) +;;;; 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. -(defvar *gc-trigger* nil) - +;;; +;;; 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) -;;;; The following specials are used to control when garbage collection -;;;; occurs. - -;;; When non-NIL, inhibits garbage collection. +;;; When >0, 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 - "This 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 sb!alien:int)) - -(sb!alien:define-alien-routine set-auto-gc-trigger sb!alien:void - (dynamic-usage sb!alien:unsigned-long)) + (#!+gencgc last-gen #!-gencgc ignore sb!alien:int)) -(sb!alien:define-alien-routine clear-auto-gc-trigger sb!alien:void) +#!+sb-thread +(def-c-var-frob gc-thread-pid "gc_thread_pid") -;;; 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 @@ -265,132 +218,54 @@ function should notify the user that the system has finished GC'ing.") (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 +;;; (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 - #!-gencgc (funcall *internal-gc*) - ;; FIXME: This EQ test is pretty gross. Among its other - ;; nastinesses, it looks as though it could break if we - ;; recompile COLLECT-GARBAGE. We should probably just - ;; straighten out the interface so that all *INTERNAL-GC* - ;; functions accept a GEN argument (and then the - ;; non-generational ones just ignore it). - #!+gencgc (if (eq *internal-gc* #'collect-garbage) - (funcall *internal-gc* gen) - (funcall *internal-gc*))) - (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) +#!+sb-thread +(defun sub-gc (&key (gen 0) &aux (pre-gc-dynamic-usage (dynamic-usage))) + (setf *need-to-collect-garbage* t) + (when (zerop *gc-inhibit*) + (setf (sb!alien:extern-alien "maybe_gc_pending" (sb!alien:unsigned 32)) + (1+ gen)) + (if (zerop (sb!alien:extern-alien "stop_the_world" (sb!alien:unsigned 32))) + (sb!unix:unix-kill (gc-thread-pid) :SIGALRM)) + (loop + (when (zerop + (sb!alien:extern-alien "maybe_gc_pending" (sb!alien:unsigned 32))) + (return nil))) + (incf *n-bytes-freed-or-purified* + (max 0 (- pre-gc-dynamic-usage (dynamic-usage)))) + (setf *need-to-collect-garbage* nil) + (scrub-control-stack)) + (values)) + +#!-sb-thread +(defvar *already-in-gc* nil "System is running SUB-GC") +#!-sb-thread +(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*) + (let ((*already-in-gc* t)) + (without-interrupts (collect-garbage gen)) + (incf *n-bytes-freed-or-purified* + (max 0 (- pre-gc-dynamic-usage (dynamic-usage)))) + (setf *need-to-collect-garbage* nil)) + (scrub-control-stack)) + (values)) + + ;;; This is the user-advertised garbage collection function. (defun gc (&key (gen 0) (full nil) &allow-other-keys) @@ -400,7 +275,7 @@ 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))) ;;;; auxiliary functions @@ -409,30 +284,19 @@ 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)) (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) @@ -440,13 +304,6 @@ 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*))))