/* -----------------------------------------------------------------------------
- * $Id: GC.c,v 1.14 1999/01/19 15:41:56 simonm Exp $
+ * $Id: GC.c,v 1.15 1999/01/19 17:06:02 simonm Exp $
*
* Two-space garbage collector
*
*/
static rtsBool failed_to_evac;
+/* Old to-space (used for two-space collector only)
+ */
+bdescr *old_to_space;
+
/* -----------------------------------------------------------------------------
Static function declarations
-------------------------------------------------------------------------- */
/* 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;
zeroMutableList(generations[RtsFlags.GcFlags.generations-1].mut_list);
}
+ /* Save the old to-space if we're doing a two-space collection
+ */
+ if (RtsFlags.GcFlags.generations == 1) {
+ old_to_space = g0s0->to_space;
+ g0s0->to_space = NULL;
+ }
+
/* Initialise to-space in all the generations/steps that we're
* collecting.
*/
generations[g].mut_list = END_MUT_LIST;
for (s = 0; s < generations[g].n_steps; s++) {
+
/* generation 0, step 0 doesn't need to-space */
- if (g == 0 && s == 0) { continue; }
+ if (g == 0 && s == 0 && RtsFlags.GcFlags.generations > 1) {
+ continue;
+ }
+
/* Get a free block for to-space. Extra blocks will be chained on
* as necessary.
*/
* twice the amount of live data plus whatever space the other
* generations need.
*/
- if (major_gc) {
- oldest_gen->max_blocks =
- stg_max(oldest_gen->steps[0].to_blocks * RtsFlags.GcFlags.oldGenFactor,
- RtsFlags.GcFlags.minOldGenSize);
- if (oldest_gen->max_blocks > RtsFlags.GcFlags.maxHeapSize / 2) {
- oldest_gen->max_blocks = RtsFlags.GcFlags.maxHeapSize / 2;
- if (((int)oldest_gen->max_blocks - (int)oldest_gen->steps[0].to_blocks) <
- (RtsFlags.GcFlags.pcFreeHeap *
- RtsFlags.GcFlags.maxHeapSize / 200)) {
+ if (RtsFlags.GcFlags.generations > 1) {
+ if (major_gc) {
+ oldest_gen->max_blocks =
+ stg_max(oldest_gen->steps[0].to_blocks * RtsFlags.GcFlags.oldGenFactor,
+ RtsFlags.GcFlags.minOldGenSize);
+ if (oldest_gen->max_blocks > RtsFlags.GcFlags.maxHeapSize / 2) {
+ oldest_gen->max_blocks = RtsFlags.GcFlags.maxHeapSize / 2;
+ if (((int)oldest_gen->max_blocks -
+ (int)oldest_gen->steps[0].to_blocks) <
+ (RtsFlags.GcFlags.pcFreeHeap *
+ RtsFlags.GcFlags.maxHeapSize / 200)) {
+ }
+ }
+ }
+ } else {
+ /* For a two-space collector, we need to resize the nursery. */
+
+ /* set up a new nursery. Allocate a nursery size based on a
+ * function of the amount of live data (currently a factor of 2,
+ * should be configurable (ToDo)). Use the blocks from the old
+ * nursery if possible, freeing up any left over blocks.
+ *
+ * If we get near the maximum heap size, then adjust our nursery
+ * size accordingly. If the nursery is the same size as the live
+ * data (L), then we need 3L bytes. We can reduce the size of the
+ * nursery to bring the required memory down near 2L bytes.
+ *
+ * A normal 2-space collector would need 4L bytes to give the same
+ * performance we get from 3L bytes, reducing to the same
+ * performance at 2L bytes.
+ */
+ nat blocks = g0s0->to_blocks;
+
+ if ( blocks * 4 > RtsFlags.GcFlags.maxHeapSize ) {
+ int adjusted_blocks; /* signed on purpose */
+ 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));
+ pc_free = adjusted_blocks * 100 / RtsFlags.GcFlags.maxHeapSize;
+ if (pc_free < RtsFlags.GcFlags.pcFreeHeap) /* might even be < 0 */ {
heapOverflow();
}
+ blocks = adjusted_blocks;
+
+ } else {
+ blocks *= 2;
+ if (blocks < RtsFlags.GcFlags.minAllocAreaSize) {
+ blocks = RtsFlags.GcFlags.minAllocAreaSize;
+ }
+ }
+
+ if (nursery_blocks < blocks) {
+ IF_DEBUG(gc, fprintf(stderr, "Increasing size of nursery to %d blocks\n",
+ blocks));
+ g0s0->blocks = allocNursery(g0s0->blocks, blocks-nursery_blocks);
+ } else {
+ bdescr *next_bd;
+
+ IF_DEBUG(gc, fprintf(stderr, "Decreasing size of nursery to %d blocks\n",
+ blocks));
+ for (bd = g0s0->blocks; nursery_blocks > blocks; nursery_blocks--) {
+ next_bd = bd->link;
+ freeGroup(bd);
+ bd = next_bd;
+ }
+ g0s0->blocks = bd;
}
+
+ g0s0->n_blocks = nursery_blocks = blocks;
}
-
+
/* run through all the generations/steps and tidy up
*/
for (g = 0; g < RtsFlags.GcFlags.generations; g++) {
bdescr *next;
step = &generations[g].steps[s];
- if (!(g == 0 && s == 0)) {
+ 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;
* between the maximum size of the oldest and youngest
* generations.
*
- * max_blocks = oldgen_max_blocks * G
- * -----------------------
- * oldest_gen
+ * max_blocks = alloc_area_size +
+ * (oldgen_max_blocks - alloc_area_size) * G
+ * -----------------------------------------
+ * oldest_gen
*/
if (g != 0) {
generations[g].max_blocks =
- stg_max(RtsFlags.GcFlags.minOldGenSize,
- (oldest_gen->max_blocks * g) /
- (RtsFlags.GcFlags.generations-1));
+ RtsFlags.GcFlags.minAllocAreaSize +
+ (((oldest_gen->max_blocks - RtsFlags.GcFlags.minAllocAreaSize) * g)
+ / (RtsFlags.GcFlags.generations-1));
}
/* for older generations... */
}
}
+ /* Two-space collector:
+ * Free the old to-space, and estimate the amount of live data.
+ */
+ if (RtsFlags.GcFlags.generations == 1) {
+ if (old_to_space != NULL) {
+ freeChain(old_to_space);
+ }
+ live = g0s0->to_blocks * BLOCK_SIZE_W +
+ ((lnat)g0s0->hp_bd->free - (lnat)g0s0->hp_bd->start) / sizeof(W_);
+
+ /* Generational collector:
+ * estimate the amount of live data.
+ */
+ } else {
+ live = 0;
+ for (g = 0; g < RtsFlags.GcFlags.generations; g++) {
+ for (s = 0; s < generations[g].n_steps; s++) {
+ /* approximate amount of live data (doesn't take into account slop
+ * at end of each block). ToDo: this more accurately.
+ */
+ if (g == 0 && s == 0) { continue; }
+ step = &generations[g].steps[s];
+ live += step->n_blocks * BLOCK_SIZE_W +
+ ((lnat)step->hp_bd->free -(lnat)step->hp_bd->start) / sizeof(W_);
+ }
+ }
+ }
+
/* revert dead CAFs and update enteredCAFs list */
revertDeadCAFs();
}
current_nursery = g0s0->blocks;
- live = 0;
- for (g = 0; g < RtsFlags.GcFlags.generations; g++) {
- for (s = 0; s < generations[g].n_steps; s++) {
- /* approximate amount of live data (doesn't take into account slop
- * at end of each block). ToDo: this more accurately.
- */
- if (g == 0 && s == 0) { continue; }
- step = &generations[g].steps[s];
- live += step->n_blocks * BLOCK_SIZE_W +
- ((lnat)step->hp_bd->free -(lnat)step->hp_bd->start) / sizeof(W_);
- }
- }
-
/* Free the small objects allocated via allocate(), since this will
* all have been copied into G0S1 now.
*/
/* check sanity after GC */
#ifdef DEBUG
- for (g = 0; g <= N; g++) {
- for (s = 0; s < generations[g].n_steps; s++) {
- if (g == 0 && s == 0) { continue; }
- IF_DEBUG(sanity, checkHeap(generations[g].steps[s].blocks, NULL));
- IF_DEBUG(sanity, checkChain(generations[g].steps[s].large_objects));
+ if (RtsFlags.GcFlags.generations == 1) {
+ IF_DEBUG(sanity, checkHeap(g0s0->to_space, NULL));
+ IF_DEBUG(sanity, checkChain(g0s0->large_objects));
+ } else {
+
+ for (g = 0; g <= N; g++) {
+ for (s = 0; s < generations[g].n_steps; s++) {
+ if (g == 0 && s == 0) { continue; }
+ IF_DEBUG(sanity, checkHeap(generations[g].steps[s].blocks, NULL));
+ }
}
- }
- for (g = N+1; g < RtsFlags.GcFlags.generations; g++) {
- for (s = 0; s < generations[g].n_steps; s++) {
- IF_DEBUG(sanity, checkHeap(generations[g].steps[s].blocks,
- generations[g].steps[s].blocks->start));
- IF_DEBUG(sanity, checkChain(generations[g].steps[s].large_objects));
+ for (g = N+1; g < RtsFlags.GcFlags.generations; g++) {
+ for (s = 0; s < generations[g].n_steps; s++) {
+ IF_DEBUG(sanity, checkHeap(generations[g].steps[s].blocks,
+ generations[g].steps[s].blocks->start));
+ IF_DEBUG(sanity, checkChain(generations[g].steps[s].large_objects));
+ }
}
+ IF_DEBUG(sanity, checkFreeListSanity());
}
- IF_DEBUG(sanity, checkFreeListSanity());
#endif
IF_DEBUG(gc, stat_describe_gens());
/* -----------------------------------------------------------------------------
- * $Id: Storage.c,v 1.4 1999/01/19 15:07:56 simonm Exp $
+ * $Id: Storage.c,v 1.5 1999/01/19 17:06:05 simonm Exp $
*
* Storage manager front end
*
/*
* Forward references
*/
-static bdescr *allocNursery (nat blocks);
static void *stgAllocForGMP (size_t size_in_bytes);
static void *stgReallocForGMP (void *ptr, size_t old_size, size_t new_size);
static void stgDeallocForGMP (void *ptr, size_t size);
{
nat g, s;
step *step;
+ generation *gen;
initBlockAllocator();
* sizeof(struct _generation),
"initStorage: gens");
- /* set up all generations */
+ /* Initialise all generations */
for(g = 0; g < RtsFlags.GcFlags.generations; g++) {
- generations[g].no = g;
- generations[g].mut_list = END_MUT_LIST;
- generations[g].collections = 0;
- generations[g].failed_promotions = 0;
+ gen = &generations[g];
+ gen->no = g;
+ gen->mut_list = END_MUT_LIST;
+ gen->collections = 0;
+ gen->failed_promotions = 0;
+ gen->max_blocks = RtsFlags.GcFlags.minOldGenSize;
}
- /* Oldest generation: one step */
- g = RtsFlags.GcFlags.generations-1;
- generations[g].n_steps = 1;
- generations[g].steps =
- stgMallocBytes(1 * sizeof(struct _step), "initStorage: last step");
- generations[g].max_blocks = RtsFlags.GcFlags.minOldGenSize;
- step = &generations[g].steps[0];
- step->no = 0;
- step->gen = &generations[g];
- step->blocks = NULL;
- step->n_blocks = 0;
- step->to = step; /* destination is this step */
- step->hp = NULL;
- step->hpLim = NULL;
- step->hp_bd = NULL;
-
- /* set up all except the oldest generation with 2 steps */
- for(g = 0; g < RtsFlags.GcFlags.generations-1; g++) {
- generations[g].n_steps = 2;
- generations[g].steps = stgMallocBytes (2 * sizeof(struct _step),
- "initStorage: steps");
- generations[g].max_blocks = RtsFlags.GcFlags.minOldGenSize;
+ /* A couple of convenience pointers */
+ g0 = &generations[0];
+ oldest_gen = &generations[RtsFlags.GcFlags.generations-1];
+
+ /* Allocate step structures in each generation */
+ if (RtsFlags.GcFlags.generations > 1) {
+ /* Only for multiple-generations */
+
+ /* Oldest generation: one step */
+ oldest_gen->n_steps = 1;
+ oldest_gen->steps =
+ stgMallocBytes(1 * sizeof(struct _step), "initStorage: last step");
+
+ /* set up all except the oldest generation with 2 steps */
+ for(g = 0; g < RtsFlags.GcFlags.generations-1; g++) {
+ generations[g].n_steps = 2;
+ generations[g].steps = stgMallocBytes (2 * sizeof(struct _step),
+ "initStorage: steps");
+ }
+
+ } else {
+ /* single generation, i.e. a two-space collector */
+ g0->n_steps = 1;
+ g0->steps = stgMallocBytes (sizeof(struct _step), "initStorage: steps");
}
- for (g = 0; g < RtsFlags.GcFlags.generations-1; g++) {
+ /* Initialise all steps */
+ for (g = 0; g < RtsFlags.GcFlags.generations; g++) {
for (s = 0; s < generations[g].n_steps; s++) {
step = &generations[g].steps[s];
step->no = s;
step->blocks = NULL;
step->n_blocks = 0;
step->gen = &generations[g];
- if ( s == 1 ) {
- step->to = &generations[g+1].steps[0];
- } else {
- step->to = &generations[g].steps[s+1];
- }
step->hp = NULL;
step->hpLim = NULL;
step->hp_bd = NULL;
}
}
- oldest_gen = &generations[RtsFlags.GcFlags.generations-1];
+ /* Set up the destination pointers in each younger gen. step */
+ for (g = 0; g < RtsFlags.GcFlags.generations-1; g++) {
+ for (s = 0; s < generations[g].n_steps; s++) {
+ step = &generations[g].steps[s];
+ if ( s == 1 ) {
+ step->to = &generations[g+1].steps[0];
+ } else {
+ step->to = &generations[g].steps[s+1];
+ }
+ }
+ }
+
+ /* The oldest generation has one step and its destination is the
+ * same step. */
+ oldest_gen->steps[0].to = &oldest_gen->steps[0];
/* generation 0 is special: that's the nursery */
- g0 = &generations[0];
generations[0].max_blocks = 0;
/* G0S0: the allocation area */
step = &generations[0].steps[0];
g0s0 = step;
- step->blocks = allocNursery(RtsFlags.GcFlags.minAllocAreaSize);
+ step->blocks = allocNursery(NULL, RtsFlags.GcFlags.minAllocAreaSize);
step->n_blocks = RtsFlags.GcFlags.minAllocAreaSize;
nursery_blocks = RtsFlags.GcFlags.minAllocAreaSize;
current_nursery = step->blocks;
IF_DEBUG(gc, stat_describe_gens());
}
-static bdescr *
-allocNursery (nat blocks)
+extern bdescr *
+allocNursery (bdescr *last_bd, nat blocks)
{
- bdescr *last_bd, *bd;
+ bdescr *bd;
nat i;
- last_bd = NULL;
/* Allocate a nursery */
for (i=0; i < blocks; i++) {
bd = allocBlock();
void
newCAF(StgClosure* caf)
{
- const StgInfoTable *info;
-
/* Put this CAF on the mutable list for the old generation.
* This is a HACK - the IND_STATIC closure doesn't really have
* a mut_link field, but we pretend it has - in fact we re-use
oldest_gen->mut_list = (StgMutClosure *)caf;
#ifdef DEBUG
- info = get_itbl(caf);
- ASSERT(info->type == IND_STATIC);
- STATIC_LINK2(info,caf) = caf_list;
- caf_list = caf;
+ {
+ const StgInfoTable *info;
+
+ info = get_itbl(caf);
+ ASSERT(info->type == IND_STATIC);
+ STATIC_LINK2(info,caf) = caf_list;
+ caf_list = caf;
+ }
#endif
}
lnat total_blocks = 0, free_blocks = 0;
/* count the blocks we current have */
+
for (g = 0; g < RtsFlags.GcFlags.generations; g++) {
for (s = 0; s < generations[g].n_steps; s++) {
step = &generations[g].steps[s];
total_blocks += step->n_blocks;
+ if (RtsFlags.GcFlags.generations == 1) {
+ /* two-space collector has a to-space too :-) */
+ total_blocks += g0s0->to_blocks;
+ }
for (bd = step->large_objects; bd; bd = bd->link) {
total_blocks += bd->blocks;
/* hack for megablock groups: they have an extra block or two in
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