/* -----------------------------------------------------------------------------
- * $Id: GC.c,v 1.32 1999/02/15 14:28:19 simonm Exp $
+ * $Id: GC.c,v 1.102 2001/04/03 16:35:12 sewardj Exp $
*
* (c) The GHC Team 1998-1999
*
*
* ---------------------------------------------------------------------------*/
+//@menu
+//* Includes::
+//* STATIC OBJECT LIST::
+//* Static function declarations::
+//* Garbage Collect::
+//* Weak Pointers::
+//* Evacuation::
+//* Scavenging::
+//* Reverting CAFs::
+//* Sanity code for CAF garbage collection::
+//* Lazy black holing::
+//* Stack squeezing::
+//* Pausing a thread::
+//* Index::
+//@end menu
+
+//@node Includes, STATIC OBJECT LIST
+//@subsection Includes
+
#include "Rts.h"
#include "RtsFlags.h"
#include "RtsUtils.h"
#include "Sanity.h"
#include "GC.h"
#include "BlockAlloc.h"
+#include "MBlock.h"
#include "Main.h"
-#include "DebugProf.h"
+#include "ProfHeap.h"
#include "SchedAPI.h"
#include "Weak.h"
#include "StablePriv.h"
+#include "Prelude.h"
+#include "ParTicky.h" // ToDo: move into Rts.h
+#if defined(GRAN) || defined(PAR)
+# include "GranSimRts.h"
+# include "ParallelRts.h"
+# include "FetchMe.h"
+# if defined(DEBUG)
+# include "Printer.h"
+# include "ParallelDebug.h"
+# endif
+#endif
+#include "HsFFI.h"
+#include "Linker.h"
+#if defined(RTS_GTK_FRONTPANEL)
+#include "FrontPanel.h"
+#endif
-StgCAF* enteredCAFs;
+//@node STATIC OBJECT LIST, Static function declarations, Includes
+//@subsection STATIC OBJECT LIST
/* STATIC OBJECT LIST.
*
*/
static nat evac_gen;
-/* WEAK POINTERS
+/* Weak pointers
*/
static StgWeak *old_weak_ptr_list; /* also pending finaliser list */
static rtsBool weak_done; /* all done for this pass */
+/* List of all threads during GC
+ */
+static StgTSO *old_all_threads;
+static StgTSO *resurrected_threads;
+
/* Flag indicating failure to evacuate an object to the desired
* generation.
*/
*/
bdescr *old_to_space;
+/* Data used for allocation area sizing.
+ */
+lnat new_blocks; /* blocks allocated during this GC */
+lnat g0s0_pcnt_kept = 30; /* percentage of g0s0 live at last minor GC */
+
+/* Used to avoid long recursion due to selector thunks
+ */
+lnat thunk_selector_depth = 0;
+#define MAX_THUNK_SELECTOR_DEPTH 256
+
+//@node Static function declarations, Garbage Collect, STATIC OBJECT LIST
+//@subsection Static function declarations
+
/* -----------------------------------------------------------------------------
Static function declarations
-------------------------------------------------------------------------- */
-static StgClosure *evacuate(StgClosure *q);
-static void zeroStaticObjectList(StgClosure* first_static);
-static rtsBool traverse_weak_ptr_list(void);
-static void zeroMutableList(StgMutClosure *first);
-static void revertDeadCAFs(void);
+static StgClosure * evacuate ( StgClosure *q );
+static void zero_static_object_list ( StgClosure* first_static );
+static void zero_mutable_list ( StgMutClosure *first );
-static void scavenge_stack(StgPtr p, StgPtr stack_end);
-static void scavenge_large(step *step);
-static void scavenge(step *step);
-static void scavenge_static(void);
-static void scavenge_mutable_list(generation *g);
-static void scavenge_mut_once_list(generation *g);
+static rtsBool traverse_weak_ptr_list ( void );
+static void cleanup_weak_ptr_list ( StgWeak **list );
+
+static void scavenge_stack ( StgPtr p, StgPtr stack_end );
+static void scavenge_large ( step * );
+static void scavenge ( step * );
+static void scavenge_static ( void );
+static void scavenge_mutable_list ( generation *g );
+static void scavenge_mut_once_list ( generation *g );
#ifdef DEBUG
-static void gcCAFs(void);
+static void gcCAFs ( void );
#endif
+void revertCAFs ( void );
+void scavengeCAFs ( void );
+
+//@node Garbage Collect, Weak Pointers, Static function declarations
+//@subsection Garbage Collect
+
/* -----------------------------------------------------------------------------
GarbageCollect
- free from-space in each step, and set from-space = to-space.
-------------------------------------------------------------------------- */
+//@cindex GarbageCollect
-void GarbageCollect(void (*get_roots)(void))
+void GarbageCollect ( void (*get_roots)(void), rtsBool force_major_gc )
{
bdescr *bd;
- step *step;
- lnat live, allocated, collected = 0;
+ step *stp;
+ lnat live, allocated, collected = 0, copied = 0;
nat g, s;
#ifdef PROFILING
CostCentreStack *prev_CCS;
#endif
+#if defined(DEBUG) && defined(GRAN)
+ IF_DEBUG(gc, belch("@@ Starting garbage collection at %ld (%lx)\n",
+ Now, Now));
+#endif
+
/* tell the stats department that we've started a GC */
stat_startGC();
+ /* Init stats and print par specific (timing) info */
+ PAR_TICKY_PAR_START();
+
/* attribute any costs to CCS_GC */
#ifdef PROFILING
prev_CCS = CCCS;
CCCS = CCS_GC;
#endif
- /* We might have been called from Haskell land by _ccall_GC, in
- * which case we need to call threadPaused() because the scheduler
- * won't have done it.
- */
- if (CurrentTSO) { threadPaused(CurrentTSO); }
-
- /* Approximate how much we allocated: number of blocks in the
- * nursery + blocks allocated via allocate() - unused nusery blocks.
- * This leaves a little slop at the end of each block, and doesn't
- * take into account large objects (ToDo).
+ /* Approximate how much we allocated.
+ * Todo: only when generating stats?
*/
- allocated = (nursery_blocks * BLOCK_SIZE_W) + allocated_bytes();
- for ( bd = current_nursery->link; bd != NULL; bd = bd->link ) {
- allocated -= BLOCK_SIZE_W;
- }
+ allocated = calcAllocated();
/* Figure out which generation to collect
*/
- N = 0;
- for (g = 0; g < RtsFlags.GcFlags.generations; g++) {
- if (generations[g].steps[0].n_blocks >= generations[g].max_blocks) {
- N = g;
+ if (force_major_gc) {
+ N = RtsFlags.GcFlags.generations - 1;
+ major_gc = rtsTrue;
+ } else {
+ N = 0;
+ for (g = 0; g < RtsFlags.GcFlags.generations; g++) {
+ if (generations[g].steps[0].n_blocks >= generations[g].max_blocks) {
+ N = g;
+ }
}
+ major_gc = (N == RtsFlags.GcFlags.generations-1);
}
- major_gc = (N == RtsFlags.GcFlags.generations-1);
+
+#ifdef RTS_GTK_FRONTPANEL
+ if (RtsFlags.GcFlags.frontpanel) {
+ updateFrontPanelBeforeGC(N);
+ }
+#endif
/* check stack sanity *before* GC (ToDo: check all threads) */
- /*IF_DEBUG(sanity, checkTSO(MainTSO,0)); */
+#if defined(GRAN)
+ // ToDo!: check sanity IF_DEBUG(sanity, checkTSOsSanity());
+#endif
IF_DEBUG(sanity, checkFreeListSanity());
/* Initialise the static object lists
scavenged_static_objects = END_OF_STATIC_LIST;
/* zero the mutable list for the oldest generation (see comment by
- * zeroMutableList below).
+ * zero_mutable_list below).
*/
if (major_gc) {
- zeroMutableList(generations[RtsFlags.GcFlags.generations-1].mut_once_list);
+ zero_mutable_list(generations[RtsFlags.GcFlags.generations-1].mut_once_list);
}
/* Save the old to-space if we're doing a two-space collection
g0s0->to_space = NULL;
}
+ /* Keep a count of how many new blocks we allocated during this GC
+ * (used for resizing the allocation area, later).
+ */
+ new_blocks = 0;
+
/* Initialise to-space in all the generations/steps that we're
* collecting.
*/
* as necessary.
*/
bd = allocBlock();
- step = &generations[g].steps[s];
- ASSERT(step->gen->no == g);
- ASSERT(step->hp ? Bdescr(step->hp)->step == step : rtsTrue);
+ stp = &generations[g].steps[s];
+ ASSERT(stp->gen->no == g);
+ ASSERT(stp->hp ? Bdescr(stp->hp)->step == stp : rtsTrue);
bd->gen = &generations[g];
- bd->step = step;
+ bd->step = stp;
bd->link = NULL;
bd->evacuated = 1; /* it's a to-space block */
- step->hp = bd->start;
- step->hpLim = step->hp + BLOCK_SIZE_W;
- step->hp_bd = bd;
- step->to_space = bd;
- step->to_blocks = 1; /* ???? */
- step->scan = bd->start;
- step->scan_bd = bd;
- step->new_large_objects = NULL;
- step->scavenged_large_objects = NULL;
+ stp->hp = bd->start;
+ stp->hpLim = stp->hp + BLOCK_SIZE_W;
+ stp->hp_bd = bd;
+ stp->to_space = bd;
+ stp->to_blocks = 1;
+ stp->scan = bd->start;
+ stp->scan_bd = bd;
+ stp->new_large_objects = NULL;
+ stp->scavenged_large_objects = NULL;
+ new_blocks++;
/* mark the large objects as not evacuated yet */
- for (bd = step->large_objects; bd; bd = bd->link) {
+ for (bd = stp->large_objects; bd; bd = bd->link) {
bd->evacuated = 0;
}
}
*/
for (g = N+1; g < RtsFlags.GcFlags.generations; g++) {
for (s = 0; s < generations[g].n_steps; s++) {
- step = &generations[g].steps[s];
- if (step->hp_bd == NULL) {
+ stp = &generations[g].steps[s];
+ if (stp->hp_bd == NULL) {
bd = allocBlock();
bd->gen = &generations[g];
- bd->step = step;
+ bd->step = stp;
bd->link = NULL;
bd->evacuated = 0; /* *not* a to-space block */
- step->hp = bd->start;
- step->hpLim = step->hp + BLOCK_SIZE_W;
- step->hp_bd = bd;
- step->blocks = bd;
- step->n_blocks = 1;
+ stp->hp = bd->start;
+ stp->hpLim = stp->hp + BLOCK_SIZE_W;
+ stp->hp_bd = bd;
+ stp->blocks = bd;
+ stp->n_blocks = 1;
+ new_blocks++;
}
/* Set the scan pointer for older generations: remember we
* still have to scavenge objects that have been promoted. */
- step->scan = step->hp;
- step->scan_bd = step->hp_bd;
- step->to_space = NULL;
- step->to_blocks = 0;
- step->new_large_objects = NULL;
- step->scavenged_large_objects = NULL;
+ stp->scan = stp->hp;
+ stp->scan_bd = stp->hp_bd;
+ stp->to_space = NULL;
+ stp->to_blocks = 0;
+ stp->new_large_objects = NULL;
+ stp->scavenged_large_objects = NULL;
}
}
/* Do the mut-once lists first */
for (g = RtsFlags.GcFlags.generations-1; g > N; g--) {
+ IF_PAR_DEBUG(verbose,
+ printMutOnceList(&generations[g]));
scavenge_mut_once_list(&generations[g]);
evac_gen = g;
for (st = generations[g].n_steps-1; st >= 0; st--) {
}
for (g = RtsFlags.GcFlags.generations-1; g > N; g--) {
+ IF_PAR_DEBUG(verbose,
+ printMutableList(&generations[g]));
scavenge_mutable_list(&generations[g]);
evac_gen = g;
for (st = generations[g].n_steps-1; st >= 0; st--) {
}
}
+ scavengeCAFs();
+
/* follow all the roots that the application knows about.
*/
evac_gen = 0;
get_roots();
+#if defined(PAR)
/* And don't forget to mark the TSO if we got here direct from
* Haskell! */
+ /* Not needed in a seq version?
if (CurrentTSO) {
CurrentTSO = (StgTSO *)MarkRoot((StgClosure *)CurrentTSO);
}
+ */
+
+ /* Mark the entries in the GALA table of the parallel system */
+ markLocalGAs(major_gc);
+ /* Mark all entries on the list of pending fetches */
+ markPendingFetches(major_gc);
+#endif
/* Mark the weak pointer list, and prepare to detect dead weak
* pointers.
*/
- markWeakList();
old_weak_ptr_list = weak_ptr_list;
weak_ptr_list = NULL;
weak_done = rtsFalse;
+ /* The all_threads list is like the weak_ptr_list.
+ * See traverse_weak_ptr_list() for the details.
+ */
+ old_all_threads = all_threads;
+ all_threads = END_TSO_QUEUE;
+ resurrected_threads = END_TSO_QUEUE;
+
/* Mark the stable pointer table.
*/
markStablePtrTable(major_gc);
* the CAF document.
*/
extern void markHugsObjects(void);
-#if 0
- /* ToDo: This (undefined) function should contain the scavenge
- * loop immediately below this block of code - but I'm not sure
- * enough of the details to do this myself.
- */
- scavengeEverything();
- /* revert dead CAFs and update enteredCAFs list */
- revertDeadCAFs();
-#endif
markHugsObjects();
-#if 0
- /* This will keep the CAFs and the attached BCOs alive
- * but the values will have been reverted
- */
- scavengeEverything();
-#endif
}
#endif
/* scavenge static objects */
if (major_gc && static_objects != END_OF_STATIC_LIST) {
+ IF_DEBUG(sanity,
+ checkStaticObjects());
scavenge_static();
}
loop2:
for (gen = RtsFlags.GcFlags.generations-1; gen >= 0; gen--) {
for (st = generations[gen].n_steps-1; st >= 0 ; st--) {
- step = &generations[gen].steps[st];
+ if (gen == 0 && st == 0 && RtsFlags.GcFlags.generations > 1) {
+ continue;
+ }
+ stp = &generations[gen].steps[st];
evac_gen = gen;
- if (step->hp_bd != step->scan_bd || step->scan < step->hp) {
- scavenge(step);
+ if (stp->hp_bd != stp->scan_bd || stp->scan < stp->hp) {
+ scavenge(stp);
flag = rtsTrue;
goto loop2;
}
- if (step->new_large_objects != NULL) {
- scavenge_large(step);
+ if (stp->new_large_objects != NULL) {
+ scavenge_large(stp);
flag = rtsTrue;
goto loop2;
}
}
}
- /* Now see which stable names are still alive
+ /* Final traversal of the weak pointer list (see comment by
+ * cleanUpWeakPtrList below).
+ */
+ cleanup_weak_ptr_list(&weak_ptr_list);
+
+ /* Now see which stable names are still alive.
*/
gcStablePtrTable(major_gc);
+#if defined(PAR)
+ /* Reconstruct the Global Address tables used in GUM */
+ rebuildGAtables(major_gc);
+ IF_DEBUG(sanity, checkGlobalTSOList(rtsTrue/*check TSOs, too*/));
+ IF_DEBUG(sanity, checkLAGAtable(rtsTrue/*check closures, too*/));
+#endif
+
/* Set the maximum blocks for the oldest generation, based on twice
* the amount of live data now, adjusted to fit the maximum heap
* size if necessary.
/* run through all the generations/steps and tidy up
*/
+ copied = new_blocks * BLOCK_SIZE_W;
for (g = 0; g < RtsFlags.GcFlags.generations; g++) {
if (g <= N) {
for (s = 0; s < generations[g].n_steps; s++) {
bdescr *next;
- step = &generations[g].steps[s];
+ stp = &generations[g].steps[s];
if (!(g == 0 && s == 0 && RtsFlags.GcFlags.generations > 1)) {
/* Tidy the end of the to-space chains */
- step->hp_bd->free = step->hp;
- step->hp_bd->link = NULL;
+ stp->hp_bd->free = stp->hp;
+ stp->hp_bd->link = NULL;
+ /* stats information: how much we copied */
+ if (g <= N) {
+ copied -= stp->hp_bd->start + BLOCK_SIZE_W -
+ stp->hp_bd->free;
+ }
}
/* for generations we collected... */
if (g <= N) {
- collected += step->n_blocks * BLOCK_SIZE_W; /* for stats */
+ collected += stp->n_blocks * BLOCK_SIZE_W; /* for stats */
/* free old memory and shift to-space into from-space for all
* the collected steps (except the allocation area). These
* freed blocks will probaby be quickly recycled.
*/
if (!(g == 0 && s == 0)) {
- freeChain(step->blocks);
- step->blocks = step->to_space;
- step->n_blocks = step->to_blocks;
- step->to_space = NULL;
- step->to_blocks = 0;
- for (bd = step->blocks; bd != NULL; bd = bd->link) {
+ freeChain(stp->blocks);
+ stp->blocks = stp->to_space;
+ stp->n_blocks = stp->to_blocks;
+ stp->to_space = NULL;
+ stp->to_blocks = 0;
+ for (bd = stp->blocks; bd != NULL; bd = bd->link) {
bd->evacuated = 0; /* now from-space */
}
}
* collection from large_objects. Any objects left on
* large_objects list are therefore dead, so we free them here.
*/
- for (bd = step->large_objects; bd != NULL; bd = next) {
+ for (bd = stp->large_objects; bd != NULL; bd = next) {
next = bd->link;
freeGroup(bd);
bd = next;
}
- for (bd = step->scavenged_large_objects; bd != NULL; bd = bd->link) {
+ for (bd = stp->scavenged_large_objects; bd != NULL; bd = bd->link) {
bd->evacuated = 0;
}
- step->large_objects = step->scavenged_large_objects;
+ stp->large_objects = stp->scavenged_large_objects;
/* Set the maximum blocks for this generation, interpolating
* between the maximum size of the oldest and youngest
* oldest_gen
*/
if (g != 0) {
+#if 0
generations[g].max_blocks = (oldest_gen->max_blocks * g)
/ (RtsFlags.GcFlags.generations-1);
+#endif
+ generations[g].max_blocks = oldest_gen->max_blocks;
}
/* for older generations... */
* scavenged_large_object list (i.e. large objects that have been
* promoted during this GC) to the large_object list for that step.
*/
- for (bd = step->scavenged_large_objects; bd; bd = next) {
+ for (bd = stp->scavenged_large_objects; bd; bd = next) {
next = bd->link;
bd->evacuated = 0;
- dbl_link_onto(bd, &step->large_objects);
+ dbl_link_onto(bd, &stp->large_objects);
}
/* add the new blocks we promoted during this GC */
- step->n_blocks += step->to_blocks;
+ stp->n_blocks += stp->to_blocks;
}
}
}
/* Guess the amount of live data for stats. */
live = calcLive();
+ /* Free the small objects allocated via allocate(), since this will
+ * all have been copied into G0S1 now.
+ */
+ if (small_alloc_list != NULL) {
+ freeChain(small_alloc_list);
+ }
+ small_alloc_list = NULL;
+ alloc_blocks = 0;
+ alloc_Hp = NULL;
+ alloc_HpLim = NULL;
+ alloc_blocks_lim = RtsFlags.GcFlags.minAllocAreaSize;
+
/* Two-space collector:
* Free the old to-space, and estimate the amount of live data.
*/
int pc_free;
adjusted_blocks = (RtsFlags.GcFlags.maxHeapSize - 2 * blocks);
- IF_DEBUG(gc, fprintf(stderr, "Near maximum heap size of 0x%x blocks, blocks = %d, adjusted to %d\n", RtsFlags.GcFlags.maxHeapSize, blocks, adjusted_blocks));
+ IF_DEBUG(gc, fprintf(stderr, "@@ Near maximum heap size of 0x%x blocks, blocks = %d, adjusted to %d\n", RtsFlags.GcFlags.maxHeapSize, blocks, adjusted_blocks));
pc_free = adjusted_blocks * 100 / RtsFlags.GcFlags.maxHeapSize;
if (pc_free < RtsFlags.GcFlags.pcFreeHeap) /* might even be < 0 */ {
heapOverflow();
nat needed = calcNeeded(); /* approx blocks needed at next GC */
/* Guess how much will be live in generation 0 step 0 next time.
- * A good approximation is the amount of data that was live this
- * time: this assumes (1) that the size of G0S0 will be roughly
- * the same as last time, and (2) that the promotion rate will be
- * constant.
- *
- * If we don't know how much was live in G0S0 (because there's no
- * step 1), then assume 30% (which is usually an overestimate).
+ * A good approximation is the obtained by finding the
+ * percentage of g0s0 that was live at the last minor GC.
*/
- if (g0->n_steps == 1) {
- needed += (g0s0->n_blocks * 30) / 100;
- } else {
- needed += g0->steps[1].n_blocks;
+ if (N == 0) {
+ g0s0_pcnt_kept = (new_blocks * 100) / g0s0->n_blocks;
}
- /* Now we have a rough guess at the number of blocks needed for
- * the next GC, subtract this from the user's suggested heap size
- * and use the rest for the allocation area.
+ /* Estimate a size for the allocation area based on the
+ * information available. We might end up going slightly under
+ * or over the suggested heap size, but we should be pretty
+ * close on average.
+ *
+ * Formula: suggested - needed
+ * ----------------------------
+ * 1 + g0s0_pcnt_kept/100
+ *
+ * where 'needed' is the amount of memory needed at the next
+ * collection for collecting all steps except g0s0.
*/
- blocks = (int)RtsFlags.GcFlags.heapSizeSuggestion - (int)needed;
+ blocks =
+ (((int)RtsFlags.GcFlags.heapSizeSuggestion - (int)needed) * 100) /
+ (100 + (int)g0s0_pcnt_kept);
if (blocks < (int)RtsFlags.GcFlags.minAllocAreaSize) {
blocks = RtsFlags.GcFlags.minAllocAreaSize;
}
}
- /* revert dead CAFs and update enteredCAFs list */
- revertDeadCAFs();
-
- /* mark the garbage collected CAFs as dead */
-#ifdef DEBUG
+ /* mark the garbage collected CAFs as dead */
+#if 0 /* doesn't work at the moment */
+#if defined(DEBUG)
if (major_gc) { gcCAFs(); }
#endif
+#endif
/* zero the scavenged static object list */
if (major_gc) {
- zeroStaticObjectList(scavenged_static_objects);
+ zero_static_object_list(scavenged_static_objects);
}
/* Reset the nursery
*/
- for (bd = g0s0->blocks; bd; bd = bd->link) {
- bd->free = bd->start;
- ASSERT(bd->gen == g0);
- ASSERT(bd->step == g0s0);
- }
- current_nursery = g0s0->blocks;
-
- /* Free the small objects allocated via allocate(), since this will
- * all have been copied into G0S1 now.
- */
- if (small_alloc_list != NULL) {
- freeChain(small_alloc_list);
- }
- small_alloc_list = NULL;
- alloc_blocks = 0;
- alloc_blocks_lim = RtsFlags.GcFlags.minAllocAreaSize;
+ resetNurseries();
/* start any pending finalizers */
scheduleFinalizers(old_weak_ptr_list);
+ /* send exceptions to any threads which were about to die */
+ resurrectThreads(resurrected_threads);
+
/* check sanity after GC */
IF_DEBUG(sanity, checkSanity(N));
/* restore enclosing cost centre */
#ifdef PROFILING
+ heapCensus();
CCCS = prev_CCS;
#endif
/* check for memory leaks if sanity checking is on */
IF_DEBUG(sanity, memInventory());
+#ifdef RTS_GTK_FRONTPANEL
+ if (RtsFlags.GcFlags.frontpanel) {
+ updateFrontPanelAfterGC( N, live );
+ }
+#endif
+
/* ok, GC over: tell the stats department what happened. */
- stat_endGC(allocated, collected, live, N);
+ stat_endGC(allocated, collected, live, copied, N);
+
+ //PAR_TICKY_TP();
}
+//@node Weak Pointers, Evacuation, Garbage Collect
+//@subsection Weak Pointers
+
/* -----------------------------------------------------------------------------
Weak Pointers
probably be optimised by keeping per-generation lists of weak
pointers, but for a few weak pointers this scheme will work.
-------------------------------------------------------------------------- */
+//@cindex traverse_weak_ptr_list
static rtsBool
traverse_weak_ptr_list(void)
last_w = &old_weak_ptr_list;
for (w = old_weak_ptr_list; w; w = next_w) {
+ /* First, this weak pointer might have been evacuated. If so,
+ * remove the forwarding pointer from the weak_ptr_list.
+ */
+ if (get_itbl(w)->type == EVACUATED) {
+ w = (StgWeak *)((StgEvacuated *)w)->evacuee;
+ *last_w = w;
+ }
+
+ /* There might be a DEAD_WEAK on the list if finalizeWeak# was
+ * called on a live weak pointer object. Just remove it.
+ */
+ if (w->header.info == &stg_DEAD_WEAK_info) {
+ next_w = ((StgDeadWeak *)w)->link;
+ *last_w = next_w;
+ continue;
+ }
+
+ ASSERT(get_itbl(w)->type == WEAK);
+
+ /* Now, check whether the key is reachable.
+ */
if ((new = isAlive(w->key))) {
w->key = new;
/* evacuate the value and finalizer */
continue;
}
}
-
+
+ /* Now deal with the all_threads list, which behaves somewhat like
+ * the weak ptr list. If we discover any threads that are about to
+ * become garbage, we wake them up and administer an exception.
+ */
+ {
+ StgTSO *t, *tmp, *next, **prev;
+
+ prev = &old_all_threads;
+ for (t = old_all_threads; t != END_TSO_QUEUE; t = next) {
+
+ /* Threads which have finished or died get dropped from
+ * the list.
+ */
+ switch (t->what_next) {
+ case ThreadRelocated:
+ next = t->link;
+ *prev = next;
+ continue;
+ case ThreadKilled:
+ case ThreadComplete:
+ next = t->global_link;
+ *prev = next;
+ continue;
+ default: ;
+ }
+
+ /* Threads which have already been determined to be alive are
+ * moved onto the all_threads list.
+ */
+ (StgClosure *)tmp = isAlive((StgClosure *)t);
+ if (tmp != NULL) {
+ next = tmp->global_link;
+ tmp->global_link = all_threads;
+ all_threads = tmp;
+ *prev = next;
+ } else {
+ prev = &(t->global_link);
+ next = t->global_link;
+ }
+ }
+ }
+
/* If we didn't make any changes, then we can go round and kill all
* the dead weak pointers. The old_weak_ptr list is used as a list
* of pending finalizers later on.
*/
if (flag == rtsFalse) {
+ cleanup_weak_ptr_list(&old_weak_ptr_list);
for (w = old_weak_ptr_list; w; w = w->link) {
- w->value = evacuate(w->value);
w->finalizer = evacuate(w->finalizer);
}
+
+ /* And resurrect any threads which were about to become garbage.
+ */
+ {
+ StgTSO *t, *tmp, *next;
+ for (t = old_all_threads; t != END_TSO_QUEUE; t = next) {
+ next = t->global_link;
+ (StgClosure *)tmp = evacuate((StgClosure *)t);
+ tmp->global_link = resurrected_threads;
+ resurrected_threads = tmp;
+ }
+ }
+
weak_done = rtsTrue;
}
}
/* -----------------------------------------------------------------------------
+ After GC, the live weak pointer list may have forwarding pointers
+ on it, because a weak pointer object was evacuated after being
+ moved to the live weak pointer list. We remove those forwarding
+ pointers here.
+
+ Also, we don't consider weak pointer objects to be reachable, but
+ we must nevertheless consider them to be "live" and retain them.
+ Therefore any weak pointer objects which haven't as yet been
+ evacuated need to be evacuated now.
+ -------------------------------------------------------------------------- */
+
+//@cindex cleanup_weak_ptr_list
+
+static void
+cleanup_weak_ptr_list ( StgWeak **list )
+{
+ StgWeak *w, **last_w;
+
+ last_w = list;
+ for (w = *list; w; w = w->link) {
+
+ if (get_itbl(w)->type == EVACUATED) {
+ w = (StgWeak *)((StgEvacuated *)w)->evacuee;
+ *last_w = w;
+ }
+
+ if (Bdescr((P_)w)->evacuated == 0) {
+ (StgClosure *)w = evacuate((StgClosure *)w);
+ *last_w = w;
+ }
+ last_w = &(w->link);
+ }
+}
+
+/* -----------------------------------------------------------------------------
isAlive determines whether the given closure is still alive (after
a garbage collection) or not. It returns the new address of the
closure if it is alive, or NULL otherwise.
-------------------------------------------------------------------------- */
+//@cindex isAlive
+
StgClosure *
isAlive(StgClosure *p)
{
- StgInfoTable *info;
+ const StgInfoTable *info;
+ nat size;
while (1) {
/* alive! */
return ((StgEvacuated *)p)->evacuee;
+ case ARR_WORDS:
+ size = arr_words_sizeW((StgArrWords *)p);
+ goto large;
+
+ case MUT_ARR_PTRS:
+ case MUT_ARR_PTRS_FROZEN:
+ size = mut_arr_ptrs_sizeW((StgMutArrPtrs *)p);
+ goto large;
+
+ case TSO:
+ if (((StgTSO *)p)->what_next == ThreadRelocated) {
+ p = (StgClosure *)((StgTSO *)p)->link;
+ continue;
+ }
+
+ size = tso_sizeW((StgTSO *)p);
+ large:
+ if (size >= LARGE_OBJECT_THRESHOLD/sizeof(W_)
+ && Bdescr((P_)p)->evacuated)
+ return p;
+ else
+ return NULL;
+
default:
/* dead. */
return NULL;
}
}
+//@cindex MarkRoot
StgClosure *
MarkRoot(StgClosure *root)
{
+# if 0 && defined(PAR) && defined(DEBUG)
+ StgClosure *foo = evacuate(root);
+ // ASSERT(closure_STATIC(foo) || maybeLarge(foo) || Bdescr(foo)->evacuated);
+ ASSERT(isAlive(foo)); // must be in to-space
+ return foo;
+# else
return evacuate(root);
+# endif
}
-static void addBlock(step *step)
+//@cindex addBlock
+static void addBlock(step *stp)
{
bdescr *bd = allocBlock();
- bd->gen = step->gen;
- bd->step = step;
+ bd->gen = stp->gen;
+ bd->step = stp;
- if (step->gen->no <= N) {
+ if (stp->gen->no <= N) {
bd->evacuated = 1;
} else {
bd->evacuated = 0;
}
- step->hp_bd->free = step->hp;
- step->hp_bd->link = bd;
- step->hp = bd->start;
- step->hpLim = step->hp + BLOCK_SIZE_W;
- step->hp_bd = bd;
- step->to_blocks++;
+ stp->hp_bd->free = stp->hp;
+ stp->hp_bd->link = bd;
+ stp->hp = bd->start;
+ stp->hpLim = stp->hp + BLOCK_SIZE_W;
+ stp->hp_bd = bd;
+ stp->to_blocks++;
+ new_blocks++;
}
+//@cindex upd_evacuee
+
+static __inline__ void
+upd_evacuee(StgClosure *p, StgClosure *dest)
+{
+ p->header.info = &stg_EVACUATED_info;
+ ((StgEvacuated *)p)->evacuee = dest;
+}
+
+//@cindex copy
+
static __inline__ StgClosure *
-copy(StgClosure *src, nat size, step *step)
+copy(StgClosure *src, nat size, step *stp)
{
P_ to, from, dest;
* evacuate to an older generation, adjust it here (see comment
* by evacuate()).
*/
- if (step->gen->no < evac_gen) {
- step = &generations[evac_gen].steps[0];
+ if (stp->gen->no < evac_gen) {
+#ifdef NO_EAGER_PROMOTION
+ failed_to_evac = rtsTrue;
+#else
+ stp = &generations[evac_gen].steps[0];
+#endif
}
/* chain a new block onto the to-space for the destination step if
* necessary.
*/
- if (step->hp + size >= step->hpLim) {
- addBlock(step);
+ if (stp->hp + size >= stp->hpLim) {
+ addBlock(stp);
}
- for(to = step->hp, from = (P_)src; size>0; --size) {
+ for(to = stp->hp, from = (P_)src; size>0; --size) {
*to++ = *from++;
}
- dest = step->hp;
- step->hp = to;
+ dest = stp->hp;
+ stp->hp = to;
+ upd_evacuee(src,(StgClosure *)dest);
return (StgClosure *)dest;
}
* used to optimise evacuation of BLACKHOLEs.
*/
+//@cindex copyPart
+
static __inline__ StgClosure *
-copyPart(StgClosure *src, nat size_to_reserve, nat size_to_copy, step *step)
+copyPart(StgClosure *src, nat size_to_reserve, nat size_to_copy, step *stp)
{
P_ dest, to, from;
TICK_GC_WORDS_COPIED(size_to_copy);
- if (step->gen->no < evac_gen) {
- step = &generations[evac_gen].steps[0];
+ if (stp->gen->no < evac_gen) {
+#ifdef NO_EAGER_PROMOTION
+ failed_to_evac = rtsTrue;
+#else
+ stp = &generations[evac_gen].steps[0];
+#endif
}
- if (step->hp + size_to_reserve >= step->hpLim) {
- addBlock(step);
+ if (stp->hp + size_to_reserve >= stp->hpLim) {
+ addBlock(stp);
}
- for(to = step->hp, from = (P_)src; size_to_copy>0; --size_to_copy) {
+ for(to = stp->hp, from = (P_)src; size_to_copy>0; --size_to_copy) {
*to++ = *from++;
}
- dest = step->hp;
- step->hp += size_to_reserve;
+ dest = stp->hp;
+ stp->hp += size_to_reserve;
+ upd_evacuee(src,(StgClosure *)dest);
return (StgClosure *)dest;
}
-static __inline__ void
-upd_evacuee(StgClosure *p, StgClosure *dest)
-{
- StgEvacuated *q = (StgEvacuated *)p;
-
- SET_INFO(q,&EVACUATED_info);
- q->evacuee = dest;
-}
+//@node Evacuation, Scavenging, Weak Pointers
+//@subsection Evacuation
/* -----------------------------------------------------------------------------
Evacuate a large object
evacuated, or 0 otherwise.
-------------------------------------------------------------------------- */
+//@cindex evacuate_large
+
static inline void
evacuate_large(StgPtr p, rtsBool mutable)
{
bdescr *bd = Bdescr(p);
- step *step;
+ step *stp;
/* should point to the beginning of the block */
ASSERT(((W_)p & BLOCK_MASK) == 0);
return;
}
- step = bd->step;
+ stp = bd->step;
/* remove from large_object list */
if (bd->back) {
bd->back->link = bd->link;
} else { /* first object in the list */
- step->large_objects = bd->link;
+ stp->large_objects = bd->link;
}
if (bd->link) {
bd->link->back = bd->back;
/* link it on to the evacuated large object list of the destination step
*/
- step = bd->step->to;
- if (step->gen->no < evac_gen) {
- step = &generations[evac_gen].steps[0];
+ stp = bd->step->to;
+ if (stp->gen->no < evac_gen) {
+#ifdef NO_EAGER_PROMOTION
+ failed_to_evac = rtsTrue;
+#else
+ stp = &generations[evac_gen].steps[0];
+#endif
}
- bd->step = step;
- bd->gen = step->gen;
- bd->link = step->new_large_objects;
- step->new_large_objects = bd;
+ bd->step = stp;
+ bd->gen = stp->gen;
+ bd->link = stp->new_large_objects;
+ stp->new_large_objects = bd;
bd->evacuated = 1;
if (mutable) {
the promotion until the next GC.
-------------------------------------------------------------------------- */
+//@cindex mkMutCons
+
static StgClosure *
mkMutCons(StgClosure *ptr, generation *gen)
{
StgMutVar *q;
- step *step;
+ step *stp;
- step = &gen->steps[0];
+ stp = &gen->steps[0];
/* chain a new block onto the to-space for the destination step if
* necessary.
*/
- if (step->hp + sizeofW(StgIndOldGen) >= step->hpLim) {
- addBlock(step);
+ if (stp->hp + sizeofW(StgIndOldGen) >= stp->hpLim) {
+ addBlock(stp);
}
- q = (StgMutVar *)step->hp;
- step->hp += sizeofW(StgMutVar);
+ q = (StgMutVar *)stp->hp;
+ stp->hp += sizeofW(StgMutVar);
- SET_HDR(q,&MUT_CONS_info,CCS_GC);
+ SET_HDR(q,&stg_MUT_CONS_info,CCS_GC);
q->var = ptr;
recordOldToNewPtrs((StgMutClosure *)q);
didn't manage to evacuate this object into evac_gen.
-------------------------------------------------------------------------- */
-
+//@cindex evacuate
static StgClosure *
evacuate(StgClosure *q)
{
StgClosure *to;
bdescr *bd = NULL;
- step *step;
+ step *stp;
const StgInfoTable *info;
loop:
- if (!LOOKS_LIKE_STATIC(q)) {
+ if (HEAP_ALLOCED(q)) {
bd = Bdescr((P_)q);
if (bd->gen->no > N) {
/* Can't evacuate this object, because it's in a generation
}
return q;
}
- step = bd->step->to;
+ stp = bd->step->to;
}
+#ifdef DEBUG
+ else stp = NULL; /* make sure copy() will crash if HEAP_ALLOCED is wrong */
+#endif
/* make sure the info pointer is into text space */
ASSERT(q && (LOOKS_LIKE_GHC_INFO(GET_INFO(q))
|| IS_HUGS_CONSTR_INFO(GET_INFO(q))));
-
info = get_itbl(q);
+ /*
+ if (info->type==RBH) {
+ info = REVERT_INFOPTR(info);
+ IF_DEBUG(gc,
+ belch("@_ Trying to evacuate an RBH %p (%s); reverting to IP %p (%s)",
+ q, info_type(q), info, info_type_by_ip(info)));
+ }
+ */
+
switch (info -> type) {
- case BCO:
- to = copy(q,bco_sizeW(stgCast(StgBCO*,q)),step);
- upd_evacuee(q,to);
- return to;
-
case MUT_VAR:
- ASSERT(q->header.info != &MUT_CONS_info);
+ ASSERT(q->header.info != &stg_MUT_CONS_info);
case MVAR:
- to = copy(q,sizeW_fromITBL(info),step);
- upd_evacuee(q,to);
+ to = copy(q,sizeW_fromITBL(info),stp);
recordMutable((StgMutClosure *)to);
return to;
- case STABLE_NAME:
- stable_ptr_table[((StgStableName *)q)->sn].keep = rtsTrue;
- to = copy(q,sizeofW(StgStableName),step);
- upd_evacuee(q,to);
- return to;
+ case CONSTR_0_1:
+ {
+ StgWord w = (StgWord)q->payload[0];
+ if (q->header.info == Czh_con_info &&
+ /* unsigned, so always true: (StgChar)w >= MIN_CHARLIKE && */
+ (StgChar)w <= MAX_CHARLIKE) {
+ return (StgClosure *)CHARLIKE_CLOSURE((StgChar)w);
+ }
+ if (q->header.info == Izh_con_info &&
+ (StgInt)w >= MIN_INTLIKE && (StgInt)w <= MAX_INTLIKE) {
+ return (StgClosure *)INTLIKE_CLOSURE((StgInt)w);
+ }
+ /* else, fall through ... */
+ }
case FUN_1_0:
case FUN_0_1:
case CONSTR_1_0:
- case CONSTR_0_1:
- to = copy(q,sizeofW(StgHeader)+1,step);
- upd_evacuee(q,to);
- return to;
+ return copy(q,sizeofW(StgHeader)+1,stp);
case THUNK_1_0: /* here because of MIN_UPD_SIZE */
case THUNK_0_1:
- case FUN_1_1:
- case FUN_0_2:
- case FUN_2_0:
case THUNK_1_1:
case THUNK_0_2:
case THUNK_2_0:
+#ifdef NO_PROMOTE_THUNKS
+ if (bd->gen->no == 0 &&
+ bd->step->no != 0 &&
+ bd->step->no == bd->gen->n_steps-1) {
+ stp = bd->step;
+ }
+#endif
+ return copy(q,sizeofW(StgHeader)+2,stp);
+
+ case FUN_1_1:
+ case FUN_0_2:
+ case FUN_2_0:
case CONSTR_1_1:
case CONSTR_0_2:
case CONSTR_2_0:
- to = copy(q,sizeofW(StgHeader)+2,step);
- upd_evacuee(q,to);
- return to;
+ return copy(q,sizeofW(StgHeader)+2,stp);
case FUN:
case THUNK:
case CONSTR:
case IND_PERM:
case IND_OLDGEN_PERM:
- case CAF_UNENTERED:
- case CAF_ENTERED:
case WEAK:
case FOREIGN:
- to = copy(q,sizeW_fromITBL(info),step);
- upd_evacuee(q,to);
- return to;
+ case STABLE_NAME:
+ case BCO:
+ return copy(q,sizeW_fromITBL(info),stp);
case CAF_BLACKHOLE:
+ case SE_CAF_BLACKHOLE:
+ case SE_BLACKHOLE:
case BLACKHOLE:
- to = copyPart(q,BLACKHOLE_sizeW(),sizeofW(StgHeader),step);
- upd_evacuee(q,to);
- return to;
+ return copyPart(q,BLACKHOLE_sizeW(),sizeofW(StgHeader),stp);
case BLACKHOLE_BQ:
- to = copy(q,BLACKHOLE_sizeW(),step);
- upd_evacuee(q,to);
+ to = copy(q,BLACKHOLE_sizeW(),stp);
recordMutable((StgMutClosure *)to);
return to;
case CONSTR_0_2:
case CONSTR_STATIC:
{
- StgNat32 offset = info->layout.selector_offset;
+ StgWord32 offset = info->layout.selector_offset;
/* check that the size is in range */
ASSERT(offset <
- (StgNat32)(selectee_info->layout.payload.ptrs +
+ (StgWord32)(selectee_info->layout.payload.ptrs +
selectee_info->layout.payload.nptrs));
/* perform the selection! */
* with the evacuation, just update the source address with
* a pointer to the (evacuated) constructor field.
*/
- if (IS_USER_PTR(q)) {
+ if (HEAP_ALLOCED(q)) {
bdescr *bd = Bdescr((P_)q);
if (bd->evacuated) {
if (bd->gen->no < evac_gen) {
case IND_PERM:
case IND_OLDGEN:
case IND_OLDGEN_PERM:
- selectee = stgCast(StgInd *,selectee)->indirectee;
- goto selector_loop;
-
- case CAF_ENTERED:
- selectee = stgCast(StgCAF *,selectee)->value;
+ selectee = ((StgInd *)selectee)->indirectee;
goto selector_loop;
case EVACUATED:
- selectee = stgCast(StgEvacuated*,selectee)->evacuee;
+ selectee = ((StgEvacuated *)selectee)->evacuee;
goto selector_loop;
+ case THUNK_SELECTOR:
+# if 0
+ /* Disabled 03 April 2001 by JRS; it seems to cause the GC (or
+ something) to go into an infinite loop when the nightly
+ stage2 compiles PrelTup.lhs. */
+
+ /* we can't recurse indefinitely in evacuate(), so set a
+ * limit on the number of times we can go around this
+ * loop.
+ */
+ if (thunk_selector_depth < MAX_THUNK_SELECTOR_DEPTH) {
+ bdescr *bd;
+ bd = Bdescr((P_)selectee);
+ if (!bd->evacuated) {
+ thunk_selector_depth++;
+ selectee = evacuate(selectee);
+ thunk_selector_depth--;
+ goto selector_loop;
+ }
+ }
+ /* otherwise, fall through... */
+# endif
+
+ case AP_UPD:
case THUNK:
case THUNK_1_0:
case THUNK_0_1:
case THUNK_1_1:
case THUNK_0_2:
case THUNK_STATIC:
- case THUNK_SELECTOR:
- /* aargh - do recursively???? */
- case CAF_UNENTERED:
case CAF_BLACKHOLE:
+ case SE_CAF_BLACKHOLE:
+ case SE_BLACKHOLE:
case BLACKHOLE:
case BLACKHOLE_BQ:
/* not evaluated yet */
break;
+#if defined(PAR)
+ /* a copy of the top-level cases below */
+ case RBH: // cf. BLACKHOLE_BQ
+ {
+ //StgInfoTable *rip = get_closure_info(q, &size, &ptrs, &nonptrs, &vhs, str);
+ to = copy(q,BLACKHOLE_sizeW(),stp);
+ //ToDo: derive size etc from reverted IP
+ //to = copy(q,size,stp);
+ // recordMutable((StgMutClosure *)to);
+ return to;
+ }
+
+ case BLOCKED_FETCH:
+ ASSERT(sizeofW(StgBlockedFetch) >= MIN_NONUPD_SIZE);
+ to = copy(q,sizeofW(StgBlockedFetch),stp);
+ return to;
+
+# ifdef DIST
+ case REMOTE_REF:
+# endif
+ case FETCH_ME:
+ ASSERT(sizeofW(StgBlockedFetch) >= MIN_UPD_SIZE);
+ to = copy(q,sizeofW(StgFetchMe),stp);
+ return to;
+
+ case FETCH_ME_BQ:
+ ASSERT(sizeofW(StgBlockedFetch) >= MIN_UPD_SIZE);
+ to = copy(q,sizeofW(StgFetchMeBlockingQueue),stp);
+ return to;
+#endif
+
default:
- barf("evacuate: THUNK_SELECTOR: strange selectee");
+ barf("evacuate: THUNK_SELECTOR: strange selectee %d",
+ (int)(selectee_info->type));
}
}
- to = copy(q,THUNK_SELECTOR_sizeW(),step);
- upd_evacuee(q,to);
- return to;
+ return copy(q,THUNK_SELECTOR_sizeW(),stp);
case IND:
case IND_OLDGEN:
q = ((StgInd*)q)->indirectee;
goto loop;
- /* ToDo: optimise STATIC_LINK for known cases.
- - FUN_STATIC : payload[0]
- - THUNK_STATIC : payload[1]
- - IND_STATIC : payload[1]
- */
case THUNK_STATIC:
+ if (info->srt_len > 0 && major_gc &&
+ THUNK_STATIC_LINK((StgClosure *)q) == NULL) {
+ THUNK_STATIC_LINK((StgClosure *)q) = static_objects;
+ static_objects = (StgClosure *)q;
+ }
+ return q;
+
case FUN_STATIC:
- if (info->srt_len == 0) { /* small optimisation */
- return q;
+ if (info->srt_len > 0 && major_gc &&
+ FUN_STATIC_LINK((StgClosure *)q) == NULL) {
+ FUN_STATIC_LINK((StgClosure *)q) = static_objects;
+ static_objects = (StgClosure *)q;
}
- /* fall through */
- case CONSTR_STATIC:
+ return q;
+
case IND_STATIC:
- /* don't want to evacuate these, but we do want to follow pointers
- * from SRTs - see scavenge_static.
+ /* If q->saved_info != NULL, then it's a revertible CAF - it'll be
+ * on the CAF list, so don't do anything with it here (we'll
+ * scavenge it later).
*/
+ if (major_gc
+ && ((StgIndStatic *)q)->saved_info == NULL
+ && IND_STATIC_LINK((StgClosure *)q) == NULL) {
+ IND_STATIC_LINK((StgClosure *)q) = static_objects;
+ static_objects = (StgClosure *)q;
+ }
+ return q;
- /* put the object on the static list, if necessary.
- */
+ case CONSTR_STATIC:
if (major_gc && STATIC_LINK(info,(StgClosure *)q) == NULL) {
STATIC_LINK(info,(StgClosure *)q) = static_objects;
static_objects = (StgClosure *)q;
}
- /* fall through */
+ return q;
case CONSTR_INTLIKE:
case CONSTR_CHARLIKE:
case CATCH_FRAME:
case SEQ_FRAME:
/* shouldn't see these */
- barf("evacuate: stack frame\n");
+ barf("evacuate: stack frame at %p\n", q);
case AP_UPD:
case PAP:
- /* these are special - the payload is a copy of a chunk of stack,
- tagging and all. */
- to = copy(q,pap_sizeW(stgCast(StgPAP*,q)),step);
- upd_evacuee(q,to);
- return to;
+ /* PAPs and AP_UPDs are special - the payload is a copy of a chunk
+ * of stack, tagging and all.
+ *
+ * They can be larger than a block in size. Both are only
+ * allocated via allocate(), so they should be chained on to the
+ * large_object list.
+ */
+ {
+ nat size = pap_sizeW((StgPAP*)q);
+ if (size >= LARGE_OBJECT_THRESHOLD/sizeof(W_)) {
+ evacuate_large((P_)q, rtsFalse);
+ return q;
+ } else {
+ return copy(q,size,stp);
+ }
+ }
case EVACUATED:
/* Already evacuated, just return the forwarding address.
if (evac_gen > 0) { /* optimisation */
StgClosure *p = ((StgEvacuated*)q)->evacuee;
if (Bdescr((P_)p)->gen->no < evac_gen) {
- /* fprintf(stderr,"evac failed!\n");*/
+ IF_DEBUG(gc, belch("@@ evacuate: evac of EVACUATED node %p failed!", p));
failed_to_evac = rtsTrue;
TICK_GC_FAILED_PROMOTION();
}
case ARR_WORDS:
{
- nat size = arr_words_sizeW(stgCast(StgArrWords*,q));
+ nat size = arr_words_sizeW((StgArrWords *)q);
if (size >= LARGE_OBJECT_THRESHOLD/sizeof(W_)) {
evacuate_large((P_)q, rtsFalse);
return q;
} else {
/* just copy the block */
- to = copy(q,size,step);
- upd_evacuee(q,to);
- return to;
+ return copy(q,size,stp);
}
}
case MUT_ARR_PTRS:
case MUT_ARR_PTRS_FROZEN:
{
- nat size = mut_arr_ptrs_sizeW(stgCast(StgMutArrPtrs*,q));
+ nat size = mut_arr_ptrs_sizeW((StgMutArrPtrs *)q);
if (size >= LARGE_OBJECT_THRESHOLD/sizeof(W_)) {
evacuate_large((P_)q, info->type == MUT_ARR_PTRS);
to = q;
} else {
/* just copy the block */
- to = copy(q,size,step);
- upd_evacuee(q,to);
+ to = copy(q,size,stp);
if (info->type == MUT_ARR_PTRS) {
recordMutable((StgMutClosure *)to);
}
case TSO:
{
- StgTSO *tso = stgCast(StgTSO *,q);
+ StgTSO *tso = (StgTSO *)q;
nat size = tso_sizeW(tso);
int diff;
+ /* Deal with redirected TSOs (a TSO that's had its stack enlarged).
+ */
+ if (tso->what_next == ThreadRelocated) {
+ q = (StgClosure *)tso->link;
+ goto loop;
+ }
+
/* Large TSOs don't get moved, so no relocation is required.
*/
if (size >= LARGE_OBJECT_THRESHOLD/sizeof(W_)) {
* list it contains.
*/
} else {
- StgTSO *new_tso = (StgTSO *)copy((StgClosure *)tso,tso_sizeW(tso),step);
+ StgTSO *new_tso = (StgTSO *)copy((StgClosure *)tso,tso_sizeW(tso),stp);
diff = (StgPtr)new_tso - (StgPtr)tso; /* In *words* */
/* relocate the stack pointers... */
new_tso->su = (StgUpdateFrame *) ((StgPtr)new_tso->su + diff);
new_tso->sp = (StgPtr)new_tso->sp + diff;
- new_tso->splim = (StgPtr)new_tso->splim + diff;
relocate_TSO(tso, new_tso);
- upd_evacuee(q,(StgClosure *)new_tso);
recordMutable((StgMutClosure *)new_tso);
return (StgClosure *)new_tso;
}
}
+#if defined(PAR)
+ case RBH: // cf. BLACKHOLE_BQ
+ {
+ //StgInfoTable *rip = get_closure_info(q, &size, &ptrs, &nonptrs, &vhs, str);
+ to = copy(q,BLACKHOLE_sizeW(),stp);
+ //ToDo: derive size etc from reverted IP
+ //to = copy(q,size,stp);
+ recordMutable((StgMutClosure *)to);
+ IF_DEBUG(gc,
+ belch("@@ evacuate: RBH %p (%s) to %p (%s)",
+ q, info_type(q), to, info_type(to)));
+ return to;
+ }
+
case BLOCKED_FETCH:
+ ASSERT(sizeofW(StgBlockedFetch) >= MIN_NONUPD_SIZE);
+ to = copy(q,sizeofW(StgBlockedFetch),stp);
+ IF_DEBUG(gc,
+ belch("@@ evacuate: %p (%s) to %p (%s)",
+ q, info_type(q), to, info_type(to)));
+ return to;
+
+# ifdef DIST
+ case REMOTE_REF:
+# endif
case FETCH_ME:
- fprintf(stderr,"evacuate: unimplemented/strange closure type\n");
- return q;
+ ASSERT(sizeofW(StgBlockedFetch) >= MIN_UPD_SIZE);
+ to = copy(q,sizeofW(StgFetchMe),stp);
+ IF_DEBUG(gc,
+ belch("@@ evacuate: %p (%s) to %p (%s)",
+ q, info_type(q), to, info_type(to)));
+ return to;
+
+ case FETCH_ME_BQ:
+ ASSERT(sizeofW(StgBlockedFetch) >= MIN_UPD_SIZE);
+ to = copy(q,sizeofW(StgFetchMeBlockingQueue),stp);
+ IF_DEBUG(gc,
+ belch("@@ evacuate: %p (%s) to %p (%s)",
+ q, info_type(q), to, info_type(to)));
+ return to;
+#endif
default:
- barf("evacuate: strange closure type");
+ barf("evacuate: strange closure type %d", (int)(info->type));
}
barf("evacuate");
relocate_TSO is called just after a TSO has been copied from src to
dest. It adjusts the update frame list for the new location.
-------------------------------------------------------------------------- */
+//@cindex relocate_TSO
StgTSO *
relocate_TSO(StgTSO *src, StgTSO *dest)
break;
default:
- barf("relocate_TSO");
+ barf("relocate_TSO %d", (int)(get_itbl(su)->type));
}
break;
}
return dest;
}
+//@node Scavenging, Reverting CAFs, Evacuation
+//@subsection Scavenging
+
+//@cindex scavenge_srt
+
static inline void
scavenge_srt(const StgInfoTable *info)
{
* srt field in the info table. That's ok, because we'll
* never dereference it.
*/
- srt = stgCast(StgClosure **,info->srt);
+ srt = (StgClosure **)(info->srt);
srt_end = srt + info->srt_len;
for (; srt < srt_end; srt++) {
- evacuate(*srt);
+ /* Special-case to handle references to closures hiding out in DLLs, since
+ double indirections required to get at those. The code generator knows
+ which is which when generating the SRT, so it stores the (indirect)
+ reference to the DLL closure in the table by first adding one to it.
+ We check for this here, and undo the addition before evacuating it.
+
+ If the SRT entry hasn't got bit 0 set, the SRT entry points to a
+ closure that's fixed at link-time, and no extra magic is required.
+ */
+#ifdef ENABLE_WIN32_DLL_SUPPORT
+ if ( (unsigned long)(*srt) & 0x1 ) {
+ evacuate(*stgCast(StgClosure**,(stgCast(unsigned long, *srt) & ~0x1)));
+ } else {
+ evacuate(*srt);
+ }
+#else
+ evacuate(*srt);
+#endif
+ }
+}
+
+/* -----------------------------------------------------------------------------
+ Scavenge a TSO.
+ -------------------------------------------------------------------------- */
+
+static void
+scavengeTSO (StgTSO *tso)
+{
+ /* chase the link field for any TSOs on the same queue */
+ (StgClosure *)tso->link = evacuate((StgClosure *)tso->link);
+ if ( tso->why_blocked == BlockedOnMVar
+ || tso->why_blocked == BlockedOnBlackHole
+ || tso->why_blocked == BlockedOnException
+#if defined(PAR)
+ || tso->why_blocked == BlockedOnGA
+ || tso->why_blocked == BlockedOnGA_NoSend
+#endif
+ ) {
+ tso->block_info.closure = evacuate(tso->block_info.closure);
+ }
+ if ( tso->blocked_exceptions != NULL ) {
+ tso->blocked_exceptions =
+ (StgTSO *)evacuate((StgClosure *)tso->blocked_exceptions);
}
+ /* scavenge this thread's stack */
+ scavenge_stack(tso->sp, &(tso->stack[tso->stack_size]));
}
/* -----------------------------------------------------------------------------
scavenging a mutable object where early promotion isn't such a good
idea.
-------------------------------------------------------------------------- */
-
+//@cindex scavenge
static void
-scavenge(step *step)
+scavenge(step *stp)
{
StgPtr p, q;
const StgInfoTable *info;
bdescr *bd;
nat saved_evac_gen = evac_gen; /* used for temporarily changing evac_gen */
- p = step->scan;
- bd = step->scan_bd;
+ p = stp->scan;
+ bd = stp->scan_bd;
failed_to_evac = rtsFalse;
* evacuated objects
*/
- while (bd != step->hp_bd || p < step->hp) {
+ while (bd != stp->hp_bd || p < stp->hp) {
/* If we're at the end of this block, move on to the next block */
- if (bd != step->hp_bd && p == bd->free) {
+ if (bd != stp->hp_bd && p == bd->free) {
bd = bd->link;
p = bd->start;
continue;
|| IS_HUGS_CONSTR_INFO(GET_INFO((StgClosure *)p))));
info = get_itbl((StgClosure *)p);
- switch (info -> type) {
+ /*
+ if (info->type==RBH)
+ info = REVERT_INFOPTR(info);
+ */
- case BCO:
- {
- StgBCO* bco = stgCast(StgBCO*,p);
- nat i;
- for (i = 0; i < bco->n_ptrs; i++) {
- bcoConstCPtr(bco,i) = evacuate(bcoConstCPtr(bco,i));
- }
- p += bco_sizeW(bco);
- break;
- }
+ switch (info -> type) {
case MVAR:
/* treat MVars specially, because we don't want to evacuate the
case WEAK:
case FOREIGN:
case STABLE_NAME:
- case IND_PERM:
- case IND_OLDGEN_PERM:
- case CAF_UNENTERED:
- case CAF_ENTERED:
+ case BCO:
{
StgPtr end;
break;
}
+ case IND_PERM:
+ if (stp->gen->no != 0) {
+ SET_INFO(((StgClosure *)p), &stg_IND_OLDGEN_PERM_info);
+ }
+ /* fall through */
+ case IND_OLDGEN_PERM:
+ ((StgIndOldGen *)p)->indirectee =
+ evacuate(((StgIndOldGen *)p)->indirectee);
+ if (failed_to_evac) {
+ failed_to_evac = rtsFalse;
+ recordOldToNewPtrs((StgMutClosure *)p);
+ }
+ p += sizeofW(StgIndOldGen);
+ break;
+
case MUT_VAR:
/* ignore MUT_CONSs */
- if (((StgMutVar *)p)->header.info != &MUT_CONS_info) {
+ if (((StgMutVar *)p)->header.info != &stg_MUT_CONS_info) {
evac_gen = 0;
((StgMutVar *)p)->var = evacuate(((StgMutVar *)p)->var);
evac_gen = saved_evac_gen;
break;
case CAF_BLACKHOLE:
+ case SE_CAF_BLACKHOLE:
+ case SE_BLACKHOLE:
case BLACKHOLE:
p += BLACKHOLE_sizeW();
break;
* evacuate the function pointer too...
*/
{
- StgPAP* pap = stgCast(StgPAP*,p);
+ StgPAP* pap = (StgPAP *)p;
pap->fun = evacuate(pap->fun);
scavenge_stack((P_)pap->payload, (P_)pap->payload + pap->n_args);
case ARR_WORDS:
/* nothing to follow */
- p += arr_words_sizeW(stgCast(StgArrWords*,p));
+ p += arr_words_sizeW((StgArrWords *)p);
break;
case MUT_ARR_PTRS:
case TSO:
{
- StgTSO *tso;
-
- tso = (StgTSO *)p;
+ StgTSO *tso = (StgTSO *)p;
evac_gen = 0;
- /* chase the link field for any TSOs on the same queue */
- (StgClosure *)tso->link = evacuate((StgClosure *)tso->link);
- /* scavenge this thread's stack */
- scavenge_stack(tso->sp, &(tso->stack[tso->stack_size]));
+ scavengeTSO(tso);
evac_gen = saved_evac_gen;
p += tso_sizeW(tso);
break;
}
+#if defined(PAR)
+ case RBH: // cf. BLACKHOLE_BQ
+ {
+ // nat size, ptrs, nonptrs, vhs;
+ // char str[80];
+ // StgInfoTable *rip = get_closure_info(p, &size, &ptrs, &nonptrs, &vhs, str);
+ StgRBH *rbh = (StgRBH *)p;
+ (StgClosure *)rbh->blocking_queue =
+ evacuate((StgClosure *)rbh->blocking_queue);
+ if (failed_to_evac) {
+ failed_to_evac = rtsFalse;
+ recordMutable((StgMutClosure *)rbh);
+ }
+ IF_DEBUG(gc,
+ belch("@@ scavenge: RBH %p (%s) (new blocking_queue link=%p)",
+ p, info_type(p), (StgClosure *)rbh->blocking_queue));
+ // ToDo: use size of reverted closure here!
+ p += BLACKHOLE_sizeW();
+ break;
+ }
+
case BLOCKED_FETCH:
+ {
+ StgBlockedFetch *bf = (StgBlockedFetch *)p;
+ /* follow the pointer to the node which is being demanded */
+ (StgClosure *)bf->node =
+ evacuate((StgClosure *)bf->node);
+ /* follow the link to the rest of the blocking queue */
+ (StgClosure *)bf->link =
+ evacuate((StgClosure *)bf->link);
+ if (failed_to_evac) {
+ failed_to_evac = rtsFalse;
+ recordMutable((StgMutClosure *)bf);
+ }
+ IF_DEBUG(gc,
+ belch("@@ scavenge: %p (%s); node is now %p; exciting, isn't it",
+ bf, info_type((StgClosure *)bf),
+ bf->node, info_type(bf->node)));
+ p += sizeofW(StgBlockedFetch);
+ break;
+ }
+
+#ifdef DIST
+ case REMOTE_REF:
+#endif
case FETCH_ME:
+ p += sizeofW(StgFetchMe);
+ break; // nothing to do in this case
+
+ case FETCH_ME_BQ: // cf. BLACKHOLE_BQ
+ {
+ StgFetchMeBlockingQueue *fmbq = (StgFetchMeBlockingQueue *)p;
+ (StgClosure *)fmbq->blocking_queue =
+ evacuate((StgClosure *)fmbq->blocking_queue);
+ if (failed_to_evac) {
+ failed_to_evac = rtsFalse;
+ recordMutable((StgMutClosure *)fmbq);
+ }
+ IF_DEBUG(gc,
+ belch("@@ scavenge: %p (%s) exciting, isn't it",
+ p, info_type((StgClosure *)p)));
+ p += sizeofW(StgFetchMeBlockingQueue);
+ break;
+ }
+#endif
+
case EVACUATED:
- barf("scavenge: unimplemented/strange closure type\n");
+ barf("scavenge: unimplemented/strange closure type %d @ %p",
+ info->type, p);
default:
- barf("scavenge");
+ barf("scavenge: unimplemented/strange closure type %d @ %p",
+ info->type, p);
}
/* If we didn't manage to promote all the objects pointed to by
}
}
- step->scan_bd = bd;
- step->scan = p;
+ stp->scan_bd = bd;
+ stp->scan = p;
}
/* -----------------------------------------------------------------------------
because they contain old-to-new generation pointers. Only certain
objects can have this property.
-------------------------------------------------------------------------- */
+//@cindex scavenge_one
+
static rtsBool
scavenge_one(StgClosure *p)
{
- StgInfoTable *info;
+ const StgInfoTable *info;
rtsBool no_luck;
ASSERT(p && (LOOKS_LIKE_GHC_INFO(GET_INFO(p))
info = get_itbl(p);
+ /* ngoq moHqu'!
+ if (info->type==RBH)
+ info = REVERT_INFOPTR(info); // if it's an RBH, look at the orig closure
+ */
+
switch (info -> type) {
case FUN:
case FOREIGN:
case IND_PERM:
case IND_OLDGEN_PERM:
- case CAF_UNENTERED:
- case CAF_ENTERED:
{
StgPtr q, end;
}
case CAF_BLACKHOLE:
+ case SE_CAF_BLACKHOLE:
+ case SE_BLACKHOLE:
case BLACKHOLE:
break;
break;
default:
- barf("scavenge_one: strange object");
+ barf("scavenge_one: strange object %d", (int)(info->type));
}
no_luck = failed_to_evac;
generations older than the one being collected) as roots. We also
remove non-mutable objects from the mutable list at this point.
-------------------------------------------------------------------------- */
+//@cindex scavenge_mut_once_list
static void
scavenge_mut_once_list(generation *gen)
{
- StgInfoTable *info;
+ const StgInfoTable *info;
StgMutClosure *p, *next, *new_list;
p = gen->mut_once_list;
|| IS_HUGS_CONSTR_INFO(GET_INFO(p))));
info = get_itbl(p);
+ /*
+ if (info->type==RBH)
+ info = REVERT_INFOPTR(info); // if it's an RBH, look at the orig closure
+ */
switch(info->type) {
case IND_OLDGEN:
((StgIndOldGen *)p)->indirectee =
evacuate(((StgIndOldGen *)p)->indirectee);
-#if 0
+#ifdef DEBUG
+ if (RtsFlags.DebugFlags.gc)
/* Debugging code to print out the size of the thing we just
* promoted
*/
* it from the mutable list if possible by promoting whatever it
* points to.
*/
- ASSERT(p->header.info == &MUT_CONS_info);
+ ASSERT(p->header.info == &stg_MUT_CONS_info);
if (scavenge_one(((StgMutVar *)p)->var) == rtsTrue) {
/* didn't manage to promote everything, so put the
* MUT_CONS back on the list.
default:
/* shouldn't have anything else on the mutables list */
- barf("scavenge_mut_once_list: strange object?");
+ barf("scavenge_mut_once_list: strange object? %d", (int)(info->type));
}
}
gen->mut_once_list = new_list;
}
+//@cindex scavenge_mutable_list
static void
scavenge_mutable_list(generation *gen)
{
- StgInfoTable *info;
+ const StgInfoTable *info;
StgMutClosure *p, *next;
p = gen->saved_mut_list;
|| IS_HUGS_CONSTR_INFO(GET_INFO(p))));
info = get_itbl(p);
+ /*
+ if (info->type==RBH)
+ info = REVERT_INFOPTR(info); // if it's an RBH, look at the orig closure
+ */
switch(info->type) {
case MUT_ARR_PTRS_FROZEN:
* it from the mutable list if possible by promoting whatever it
* points to.
*/
- ASSERT(p->header.info != &MUT_CONS_info);
+ ASSERT(p->header.info != &stg_MUT_CONS_info);
((StgMutVar *)p)->var = evacuate(((StgMutVar *)p)->var);
p->mut_link = gen->mut_list;
gen->mut_list = p;
}
case TSO:
- /* follow ptrs and remove this from the mutable list */
{
StgTSO *tso = (StgTSO *)p;
- /* Don't bother scavenging if this thread is dead
- */
- if (!(tso->whatNext == ThreadComplete ||
- tso->whatNext == ThreadKilled)) {
- /* Don't need to chase the link field for any TSOs on the
- * same queue. Just scavenge this thread's stack
- */
- scavenge_stack(tso->sp, &(tso->stack[tso->stack_size]));
- }
+ scavengeTSO(tso);
/* Don't take this TSO off the mutable list - it might still
* point to some younger objects (because we set evac_gen to 0
continue;
}
+ /* Happens if a BLACKHOLE_BQ in the old generation is updated:
+ */
+ case IND_OLDGEN:
+ case IND_OLDGEN_PERM:
+ /* Try to pull the indirectee into this generation, so we can
+ * remove the indirection from the mutable list.
+ */
+ evac_gen = gen->no;
+ ((StgIndOldGen *)p)->indirectee =
+ evacuate(((StgIndOldGen *)p)->indirectee);
+ evac_gen = 0;
+
+ if (failed_to_evac) {
+ failed_to_evac = rtsFalse;
+ p->mut_link = gen->mut_once_list;
+ gen->mut_once_list = p;
+ } else {
+ p->mut_link = NULL;
+ }
+ continue;
+
+#if defined(PAR)
+ // HWL: check whether all of these are necessary
+
+ case RBH: // cf. BLACKHOLE_BQ
+ {
+ // nat size, ptrs, nonptrs, vhs;
+ // char str[80];
+ // StgInfoTable *rip = get_closure_info(p, &size, &ptrs, &nonptrs, &vhs, str);
+ StgRBH *rbh = (StgRBH *)p;
+ (StgClosure *)rbh->blocking_queue =
+ evacuate((StgClosure *)rbh->blocking_queue);
+ if (failed_to_evac) {
+ failed_to_evac = rtsFalse;
+ recordMutable((StgMutClosure *)rbh);
+ }
+ // ToDo: use size of reverted closure here!
+ p += BLACKHOLE_sizeW();
+ break;
+ }
+
+ case BLOCKED_FETCH:
+ {
+ StgBlockedFetch *bf = (StgBlockedFetch *)p;
+ /* follow the pointer to the node which is being demanded */
+ (StgClosure *)bf->node =
+ evacuate((StgClosure *)bf->node);
+ /* follow the link to the rest of the blocking queue */
+ (StgClosure *)bf->link =
+ evacuate((StgClosure *)bf->link);
+ if (failed_to_evac) {
+ failed_to_evac = rtsFalse;
+ recordMutable((StgMutClosure *)bf);
+ }
+ p += sizeofW(StgBlockedFetch);
+ break;
+ }
+
+#ifdef DIST
+ case REMOTE_REF:
+ barf("scavenge_mutable_list: REMOTE_REF %d", (int)(info->type));
+#endif
+ case FETCH_ME:
+ p += sizeofW(StgFetchMe);
+ break; // nothing to do in this case
+
+ case FETCH_ME_BQ: // cf. BLACKHOLE_BQ
+ {
+ StgFetchMeBlockingQueue *fmbq = (StgFetchMeBlockingQueue *)p;
+ (StgClosure *)fmbq->blocking_queue =
+ evacuate((StgClosure *)fmbq->blocking_queue);
+ if (failed_to_evac) {
+ failed_to_evac = rtsFalse;
+ recordMutable((StgMutClosure *)fmbq);
+ }
+ p += sizeofW(StgFetchMeBlockingQueue);
+ break;
+ }
+#endif
+
default:
/* shouldn't have anything else on the mutables list */
- barf("scavenge_mut_list: strange object?");
+ barf("scavenge_mutable_list: strange object? %d", (int)(info->type));
}
}
}
+//@cindex scavenge_static
+
static void
scavenge_static(void)
{
while (p != END_OF_STATIC_LIST) {
info = get_itbl(p);
-
+ /*
+ if (info->type==RBH)
+ info = REVERT_INFOPTR(info); // if it's an RBH, look at the orig closure
+ */
/* make sure the info pointer is into text space */
ASSERT(p && (LOOKS_LIKE_GHC_INFO(GET_INFO(p))
|| IS_HUGS_CONSTR_INFO(GET_INFO(p))));
case THUNK_STATIC:
case FUN_STATIC:
scavenge_srt(info);
- /* fall through */
+ break;
case CONSTR_STATIC:
{
}
default:
- barf("scavenge_static");
+ barf("scavenge_static: strange closure %d", (int)(info->type));
}
ASSERT(failed_to_evac == rtsFalse);
- /* get the next static object from the list. Remeber, there might
+ /* get the next static object from the list. Remember, there might
* be more stuff on this list now that we've done some evacuating!
* (static_objects is a global)
*/
objects pointed to by it. We can use the same code for walking
PAPs, since these are just sections of copied stack.
-------------------------------------------------------------------------- */
+//@cindex scavenge_stack
static void
scavenge_stack(StgPtr p, StgPtr stack_end)
{
StgPtr q;
const StgInfoTable* info;
- StgNat32 bitmap;
+ StgWord32 bitmap;
+
+ //IF_DEBUG(sanity, belch(" scavenging stack between %p and %p", p, stack_end));
/*
* Each time around this loop, we are looking at a chunk of stack
*/
while (p < stack_end) {
- q = *stgCast(StgPtr*,p);
+ q = *(P_ *)p;
/* If we've got a tag, skip over that many words on the stack */
- if (IS_ARG_TAG(stgCast(StgWord,q))) {
+ if (IS_ARG_TAG((W_)q)) {
p += ARG_SIZE(q);
p++; continue;
}
/* Is q a pointer to a closure?
*/
- if (! LOOKS_LIKE_GHC_INFO(q)) {
-
+ if (! LOOKS_LIKE_GHC_INFO(q) ) {
#ifdef DEBUG
- if (LOOKS_LIKE_STATIC(q)) { /* Is it a static closure? */
- ASSERT(closure_STATIC(stgCast(StgClosure*,q)));
- }
- /* otherwise, must be a pointer into the allocation space.
- */
+ if ( 0 && LOOKS_LIKE_STATIC_CLOSURE(q) ) { /* Is it a static closure? */
+ ASSERT(closure_STATIC((StgClosure *)q));
+ }
+ /* otherwise, must be a pointer into the allocation space. */
#endif
(StgClosure *)*p = evacuate((StgClosure *)q);
* record. All activation records have 'bitmap' style layout
* info.
*/
- info = get_itbl(stgCast(StgClosure*,p));
+ info = get_itbl((StgClosure *)p);
switch (info->type) {
/* Dynamic bitmap: the mask is stored on the stack */
case RET_DYN:
- bitmap = stgCast(StgRetDyn*,p)->liveness;
- p = &payloadWord(stgCast(StgRetDyn*,p),0);
+ bitmap = ((StgRetDyn *)p)->liveness;
+ p = (P_)&((StgRetDyn *)p)->payload[0];
goto small_bitmap;
/* probably a slow-entry point return address: */
case FUN:
case FUN_STATIC:
- p++;
+ {
+#if 0
+ StgPtr old_p = p;
+ p++; p++;
+ IF_DEBUG(sanity,
+ belch("HWL: scavenge_stack: FUN(_STATIC) adjusting p from %p to %p (instead of %p)",
+ old_p, p, old_p+1));
+#else
+ p++; /* what if FHS!=1 !? -- HWL */
+#endif
goto follow_srt;
+ }
/* Specialised code for update frames, since they're so common.
* We *know* the updatee points to a BLACKHOLE, CAF_BLACKHOLE,
{
StgUpdateFrame *frame = (StgUpdateFrame *)p;
StgClosure *to;
- StgClosureType type = get_itbl(frame->updatee)->type;
+ nat type = get_itbl(frame->updatee)->type;
p += sizeofW(StgUpdateFrame);
if (type == EVACUATED) {
continue;
} else {
bdescr *bd = Bdescr((P_)frame->updatee);
- step *step;
+ step *stp;
if (bd->gen->no > N) {
if (bd->gen->no < evac_gen) {
failed_to_evac = rtsTrue;
}
continue;
}
- step = bd->step->to;
+
+ /* Don't promote blackholes */
+ stp = bd->step;
+ if (!(stp->gen->no == 0 &&
+ stp->no != 0 &&
+ stp->no == stp->gen->n_steps-1)) {
+ stp = stp->to;
+ }
+
switch (type) {
case BLACKHOLE:
case CAF_BLACKHOLE:
to = copyPart(frame->updatee, BLACKHOLE_sizeW(),
- sizeofW(StgHeader), step);
- upd_evacuee(frame->updatee,to);
+ sizeofW(StgHeader), stp);
frame->updatee = to;
continue;
case BLACKHOLE_BQ:
- to = copy(frame->updatee, BLACKHOLE_sizeW(), step);
- upd_evacuee(frame->updatee,to);
+ to = copy(frame->updatee, BLACKHOLE_sizeW(), stp);
frame->updatee = to;
recordMutable((StgMutClosure *)to);
continue;
default:
+ /* will never be SE_{,CAF_}BLACKHOLE, since we
+ don't push an update frame for single-entry thunks. KSW 1999-01. */
barf("scavenge_stack: UPDATE_FRAME updatee");
}
}
}
/* small bitmap (< 32 entries, or 64 on a 64-bit machine) */
- case RET_BCO:
- case RET_SMALL:
- case RET_VEC_SMALL:
case STOP_FRAME:
case CATCH_FRAME:
case SEQ_FRAME:
+ case RET_BCO:
+ case RET_SMALL:
+ case RET_VEC_SMALL:
bitmap = info->layout.bitmap;
p++;
+ /* this assumes that the payload starts immediately after the info-ptr */
small_bitmap:
while (bitmap != 0) {
if ((bitmap & 1) == 0) {
}
default:
- barf("scavenge_stack: weird activation record found on stack.\n");
+ barf("scavenge_stack: weird activation record found on stack: %d", (int)(info->type));
}
}
}
objects are (repeatedly) mutable, so most of the time evac_gen will
be zero.
--------------------------------------------------------------------------- */
+//@cindex scavenge_large
static void
-scavenge_large(step *step)
+scavenge_large(step *stp)
{
bdescr *bd;
StgPtr p;
nat saved_evac_gen = evac_gen; /* used for temporarily changing evac_gen */
evac_gen = 0; /* most objects are mutable */
- bd = step->new_large_objects;
+ bd = stp->new_large_objects;
- for (; bd != NULL; bd = step->new_large_objects) {
+ for (; bd != NULL; bd = stp->new_large_objects) {
/* take this object *off* the large objects list and put it on
* the scavenged large objects list. This is so that we can
* treat new_large_objects as a stack and push new objects on
* the front when evacuating.
*/
- step->new_large_objects = bd->link;
- dbl_link_onto(bd, &step->scavenged_large_objects);
+ stp->new_large_objects = bd->link;
+ dbl_link_onto(bd, &stp->scavenged_large_objects);
p = bd->start;
- info = get_itbl(stgCast(StgClosure*,p));
+ info = get_itbl((StgClosure *)p);
switch (info->type) {
continue;
}
- case BCO:
- {
- StgBCO* bco = stgCast(StgBCO*,p);
- nat i;
- evac_gen = saved_evac_gen;
- for (i = 0; i < bco->n_ptrs; i++) {
- bcoConstCPtr(bco,i) = evacuate(bcoConstCPtr(bco,i));
- }
- evac_gen = 0;
+ case TSO:
+ scavengeTSO((StgTSO *)p);
continue;
- }
- case TSO:
+ case AP_UPD:
+ case PAP:
{
- StgTSO *tso;
+ StgPAP* pap = (StgPAP *)p;
- tso = (StgTSO *)p;
- /* chase the link field for any TSOs on the same queue */
- (StgClosure *)tso->link = evacuate((StgClosure *)tso->link);
- /* scavenge this thread's stack */
- scavenge_stack(tso->sp, &(tso->stack[tso->stack_size]));
+ evac_gen = saved_evac_gen; /* not really mutable */
+ pap->fun = evacuate(pap->fun);
+ scavenge_stack((P_)pap->payload, (P_)pap->payload + pap->n_args);
+ evac_gen = 0;
continue;
}
default:
- barf("scavenge_large: unknown/strange object");
+ barf("scavenge_large: unknown/strange object %d", (int)(info->type));
}
}
}
+//@cindex zero_static_object_list
+
static void
-zeroStaticObjectList(StgClosure* first_static)
+zero_static_object_list(StgClosure* first_static)
{
StgClosure* p;
StgClosure* link;
* It doesn't do any harm to zero all the mutable link fields on the
* mutable list.
*/
+
static void
-zeroMutableList(StgMutClosure *first)
+zero_mutable_list( StgMutClosure *first )
{
StgMutClosure *next, *c;
Reverting CAFs
-------------------------------------------------------------------------- */
-void RevertCAFs(void)
+void
+revertCAFs( void )
{
- while (enteredCAFs != END_CAF_LIST) {
- StgCAF* caf = enteredCAFs;
-
- enteredCAFs = caf->link;
- ASSERT(get_itbl(caf)->type == CAF_ENTERED);
- SET_INFO(caf,&CAF_UNENTERED_info);
- caf->value = stgCast(StgClosure*,0xdeadbeef);
- caf->link = stgCast(StgCAF*,0xdeadbeef);
- }
+ StgIndStatic *c;
+
+ for (c = (StgIndStatic *)caf_list; c != NULL;
+ c = (StgIndStatic *)c->static_link)
+ {
+ c->header.info = c->saved_info;
+ c->saved_info = NULL;
+ /* could, but not necessary: c->static_link = NULL; */
+ }
+ caf_list = NULL;
}
-void revertDeadCAFs(void)
+void
+scavengeCAFs( void )
{
- StgCAF* caf = enteredCAFs;
- enteredCAFs = END_CAF_LIST;
- while (caf != END_CAF_LIST) {
- StgCAF* next = caf->link;
-
- switch(GET_INFO(caf)->type) {
- case EVACUATED:
- {
- /* This object has been evacuated, it must be live. */
- StgCAF* new = stgCast(StgCAF*,stgCast(StgEvacuated*,caf)->evacuee);
- new->link = enteredCAFs;
- enteredCAFs = new;
- break;
- }
- case CAF_ENTERED:
- {
- SET_INFO(caf,&CAF_UNENTERED_info);
- caf->value = stgCast(StgClosure*,0xdeadbeef);
- caf->link = stgCast(StgCAF*,0xdeadbeef);
- break;
- }
- default:
- barf("revertDeadCAFs: enteredCAFs list corrupted");
- }
- caf = next;
+ StgIndStatic *c;
+
+ evac_gen = 0;
+ for (c = (StgIndStatic *)caf_list; c != NULL;
+ c = (StgIndStatic *)c->static_link)
+ {
+ c->indirectee = evacuate(c->indirectee);
}
}
-------------------------------------------------------------------------- */
#ifdef DEBUG
+//@cindex gcCAFs
+
static void
gcCAFs(void)
{
if (STATIC_LINK(info,p) == NULL) {
IF_DEBUG(gccafs, fprintf(stderr, "CAF gc'd at 0x%04x\n", (int)p));
/* black hole it */
- SET_INFO(p,&BLACKHOLE_info);
+ SET_INFO(p,&stg_BLACKHOLE_info);
p = STATIC_LINK2(info,p);
*pp = p;
}
}
#endif
+//@node Lazy black holing, Stack squeezing, Sanity code for CAF garbage collection
+//@subsection Lazy black holing
+
/* -----------------------------------------------------------------------------
Lazy black holing.
some work, we have to run down the stack and black-hole all the
closures referred to by update frames.
-------------------------------------------------------------------------- */
+//@cindex threadLazyBlackHole
static void
threadLazyBlackHole(StgTSO *tso)
switch (get_itbl(update_frame)->type) {
case CATCH_FRAME:
- update_frame = stgCast(StgCatchFrame*,update_frame)->link;
+ update_frame = ((StgCatchFrame *)update_frame)->link;
break;
case UPDATE_FRAME:
* The blackhole made for a CAF is a CAF_BLACKHOLE, so they
* don't interfere with this optimisation.
*/
- if (bh->header.info == &BLACKHOLE_info) {
+ if (bh->header.info == &stg_BLACKHOLE_info) {
return;
}
- if (bh->header.info != &BLACKHOLE_BQ_info &&
- bh->header.info != &CAF_BLACKHOLE_info) {
- SET_INFO(bh,&BLACKHOLE_info);
+ if (bh->header.info != &stg_BLACKHOLE_BQ_info &&
+ bh->header.info != &stg_CAF_BLACKHOLE_info) {
+#if (!defined(LAZY_BLACKHOLING)) && defined(DEBUG)
+ fprintf(stderr,"Unexpected lazy BHing required at 0x%04x\n",(int)bh);
+#endif
+ SET_INFO(bh,&stg_BLACKHOLE_info);
}
update_frame = update_frame->link;
break;
case SEQ_FRAME:
- update_frame = stgCast(StgSeqFrame*,update_frame)->link;
+ update_frame = ((StgSeqFrame *)update_frame)->link;
break;
case STOP_FRAME:
}
}
+//@node Stack squeezing, Pausing a thread, Lazy black holing
+//@subsection Stack squeezing
+
/* -----------------------------------------------------------------------------
* Stack squeezing
*
* lazy black holing here.
*
* -------------------------------------------------------------------------- */
+//@cindex threadSqueezeStack
static void
threadSqueezeStack(StgTSO *tso)
StgUpdateFrame *prev_frame; /* Temporally previous */
StgPtr bottom;
rtsBool prev_was_update_frame;
+#if DEBUG
+ StgUpdateFrame *top_frame;
+ nat upd_frames=0, stop_frames=0, catch_frames=0, seq_frames=0,
+ bhs=0, squeezes=0;
+ void printObj( StgClosure *obj ); // from Printer.c
+
+ top_frame = tso->su;
+#endif
bottom = &(tso->stack[tso->stack_size]);
frame = tso->su;
*/
next_frame = NULL;
- while ((P_)frame < bottom - 1) { /* bottom - 1 is the STOP_FRAME */
+ /* bottom - sizeof(StgStopFrame) is the STOP_FRAME */
+ while ((P_)frame < bottom - sizeofW(StgStopFrame)) {
prev_frame = frame->link;
frame->link = next_frame;
next_frame = frame;
frame = prev_frame;
+#if DEBUG
+ IF_DEBUG(sanity,
+ if (!(frame>=top_frame && frame<=(StgUpdateFrame *)bottom)) {
+ printObj((StgClosure *)prev_frame);
+ barf("threadSqueezeStack: current frame is rubbish %p; previous was %p\n",
+ frame, prev_frame);
+ })
+ switch (get_itbl(frame)->type) {
+ case UPDATE_FRAME:
+ upd_frames++;
+ if (frame->updatee->header.info == &stg_BLACKHOLE_info)
+ bhs++;
+ break;
+ case STOP_FRAME:
+ stop_frames++;
+ break;
+ case CATCH_FRAME:
+ catch_frames++;
+ break;
+ case SEQ_FRAME:
+ seq_frames++;
+ break;
+ default:
+ barf("Found non-frame during stack squeezing at %p (prev frame was %p)\n",
+ frame, prev_frame);
+ printObj((StgClosure *)prev_frame);
+ }
+#endif
if (get_itbl(frame)->type == UPDATE_FRAME
- && frame->updatee->header.info == &BLACKHOLE_info) {
+ && frame->updatee->header.info == &stg_BLACKHOLE_info) {
break;
}
}
StgClosure *updatee_keep = prev_frame->updatee;
StgClosure *updatee_bypass = frame->updatee;
-#if 0 /* DEBUG */
- fprintf(stderr, "squeezing frame at %p\n", frame);
+#if DEBUG
+ IF_DEBUG(gc, fprintf(stderr, "@@ squeezing frame at %p\n", frame));
+ squeezes++;
#endif
/* Deal with blocking queues. If both updatees have blocked
* slower --SDM
*/
#if 0 /* do it properly... */
- if (GET_INFO(updatee_bypass) == BLACKHOLE_BQ_info) {
+# if (!defined(LAZY_BLACKHOLING)) && defined(DEBUG)
+# error Unimplemented lazy BH warning. (KSW 1999-01)
+# endif
+ if (GET_INFO(updatee_bypass) == stg_BLACKHOLE_BQ_info
+ || GET_INFO(updatee_bypass) == stg_CAF_BLACKHOLE_info
+ ) {
/* Sigh. It has one. Don't lose those threads! */
- if (GET_INFO(updatee_keep) == BLACKHOLE_BQ_info) {
+ if (GET_INFO(updatee_keep) == stg_BLACKHOLE_BQ_info) {
/* Urgh. Two queues. Merge them. */
P_ keep_tso = ((StgBlockingQueue *)updatee_keep)->blocking_queue;
#endif
TICK_UPD_SQUEEZED();
- UPD_IND(updatee_bypass, updatee_keep); /* this wakes the threads up */
+ /* wasn't there something about update squeezing and ticky to be
+ * sorted out? oh yes: we aren't counting each enter properly
+ * in this case. See the log somewhere. KSW 1999-04-21
+ *
+ * Check two things: that the two update frames don't point to
+ * the same object, and that the updatee_bypass isn't already an
+ * indirection. Both of these cases only happen when we're in a
+ * block hole-style loop (and there are multiple update frames
+ * on the stack pointing to the same closure), but they can both
+ * screw us up if we don't check.
+ */
+ if (updatee_bypass != updatee_keep && !closure_IND(updatee_bypass)) {
+ /* this wakes the threads up */
+ UPD_IND_NOLOCK(updatee_bypass, updatee_keep);
+ }
sp = (P_)frame - 1; /* sp = stuff to slide */
displacement += sizeofW(StgUpdateFrame);
*/
if (is_update_frame) {
StgBlockingQueue *bh = (StgBlockingQueue *)frame->updatee;
- if (bh->header.info != &BLACKHOLE_BQ_info &&
- bh->header.info != &CAF_BLACKHOLE_info) {
- SET_INFO(bh,&BLACKHOLE_info);
+ if (bh->header.info != &stg_BLACKHOLE_info &&
+ bh->header.info != &stg_BLACKHOLE_BQ_info &&
+ bh->header.info != &stg_CAF_BLACKHOLE_info) {
+#if (!defined(LAZY_BLACKHOLING)) && defined(DEBUG)
+ fprintf(stderr,"Unexpected lazy BHing required at 0x%04x\n",(int)bh);
+#endif
+#ifdef DEBUG
+ /* zero out the slop so that the sanity checker can tell
+ * where the next closure is.
+ */
+ {
+ StgInfoTable *info = get_itbl(bh);
+ nat np = info->layout.payload.ptrs, nw = info->layout.payload.nptrs, i;
+ /* don't zero out slop for a THUNK_SELECTOR, because it's layout
+ * info is used for a different purpose, and it's exactly the
+ * same size as a BLACKHOLE in any case.
+ */
+ if (info->type != THUNK_SELECTOR) {
+ for (i = np; i < np + nw; i++) {
+ ((StgClosure *)bh)->payload[i] = 0;
+ }
+ }
+ }
+#endif
+ SET_INFO(bh,&stg_BLACKHOLE_info);
}
}
else
next_frame_bottom = tso->sp - 1;
-#if 0 /* DEBUG */
- fprintf(stderr, "sliding [%p, %p] by %ld\n", sp, next_frame_bottom,
- displacement);
+#if DEBUG
+ IF_DEBUG(gc,
+ fprintf(stderr, "sliding [%p, %p] by %ld\n", sp, next_frame_bottom,
+ displacement))
#endif
while (sp >= next_frame_bottom) {
tso->sp += displacement;
tso->su = prev_frame;
+#if DEBUG
+ IF_DEBUG(gc,
+ fprintf(stderr, "@@ threadSqueezeStack: squeezed %d update-frames; found %d BHs; found %d update-, %d stop-, %d catch, %d seq-frames\n",
+ squeezes, bhs, upd_frames, stop_frames, catch_frames, seq_frames))
+#endif
}
+//@node Pausing a thread, Index, Stack squeezing
+//@subsection Pausing a thread
+
/* -----------------------------------------------------------------------------
* Pausing a thread
*
* here. We also take the opportunity to do stack squeezing if it's
* turned on.
* -------------------------------------------------------------------------- */
-
+//@cindex threadPaused
void
threadPaused(StgTSO *tso)
{
else
threadLazyBlackHole(tso);
}
+
+/* -----------------------------------------------------------------------------
+ * Debugging
+ * -------------------------------------------------------------------------- */
+
+#if DEBUG
+//@cindex printMutOnceList
+void
+printMutOnceList(generation *gen)
+{
+ StgMutClosure *p, *next;
+
+ p = gen->mut_once_list;
+ next = p->mut_link;
+
+ fprintf(stderr, "@@ Mut once list %p: ", gen->mut_once_list);
+ for (; p != END_MUT_LIST; p = next, next = p->mut_link) {
+ fprintf(stderr, "%p (%s), ",
+ p, info_type((StgClosure *)p));
+ }
+ fputc('\n', stderr);
+}
+
+//@cindex printMutableList
+void
+printMutableList(generation *gen)
+{
+ StgMutClosure *p, *next;
+
+ p = gen->mut_list;
+ next = p->mut_link;
+
+ fprintf(stderr, "@@ Mutable list %p: ", gen->mut_list);
+ for (; p != END_MUT_LIST; p = next, next = p->mut_link) {
+ fprintf(stderr, "%p (%s), ",
+ p, info_type((StgClosure *)p));
+ }
+ fputc('\n', stderr);
+}
+
+//@cindex maybeLarge
+static inline rtsBool
+maybeLarge(StgClosure *closure)
+{
+ StgInfoTable *info = get_itbl(closure);
+
+ /* closure types that may be found on the new_large_objects list;
+ see scavenge_large */
+ return (info->type == MUT_ARR_PTRS ||
+ info->type == MUT_ARR_PTRS_FROZEN ||
+ info->type == TSO ||
+ info->type == ARR_WORDS);
+}
+
+
+#endif /* DEBUG */
+
+//@node Index, , Pausing a thread
+//@subsection Index
+
+//@index
+//* GarbageCollect:: @cindex\s-+GarbageCollect
+//* MarkRoot:: @cindex\s-+MarkRoot
+//* RevertCAFs:: @cindex\s-+RevertCAFs
+//* addBlock:: @cindex\s-+addBlock
+//* cleanup_weak_ptr_list:: @cindex\s-+cleanup_weak_ptr_list
+//* copy:: @cindex\s-+copy
+//* copyPart:: @cindex\s-+copyPart
+//* evacuate:: @cindex\s-+evacuate
+//* evacuate_large:: @cindex\s-+evacuate_large
+//* gcCAFs:: @cindex\s-+gcCAFs
+//* isAlive:: @cindex\s-+isAlive
+//* maybeLarge:: @cindex\s-+maybeLarge
+//* mkMutCons:: @cindex\s-+mkMutCons
+//* printMutOnceList:: @cindex\s-+printMutOnceList
+//* printMutableList:: @cindex\s-+printMutableList
+//* relocate_TSO:: @cindex\s-+relocate_TSO
+//* scavenge:: @cindex\s-+scavenge
+//* scavenge_large:: @cindex\s-+scavenge_large
+//* scavenge_mut_once_list:: @cindex\s-+scavenge_mut_once_list
+//* scavenge_mutable_list:: @cindex\s-+scavenge_mutable_list
+//* scavenge_one:: @cindex\s-+scavenge_one
+//* scavenge_srt:: @cindex\s-+scavenge_srt
+//* scavenge_stack:: @cindex\s-+scavenge_stack
+//* scavenge_static:: @cindex\s-+scavenge_static
+//* threadLazyBlackHole:: @cindex\s-+threadLazyBlackHole
+//* threadPaused:: @cindex\s-+threadPaused
+//* threadSqueezeStack:: @cindex\s-+threadSqueezeStack
+//* traverse_weak_ptr_list:: @cindex\s-+traverse_weak_ptr_list
+//* upd_evacuee:: @cindex\s-+upd_evacuee
+//* zero_mutable_list:: @cindex\s-+zero_mutable_list
+//* zero_static_object_list:: @cindex\s-+zero_static_object_list
+//@end index
projects / ghc-hetmet.git / blobdiff