/* Does a garbage collection run. Exactly what it does is configured by the
* couple of arguments that it takes.
*
* The what_to_do argument specifies where it should look for things to add
* to the worklist: everywhere, just at thread local stuff, or just in the
* thread's in-tray.
*
* The gen argument specifies whether to collect the nursery or both of the
* generations. Nursery collection is done by semi-space copying. Once an
* object is seen/copied once in the nursery (may be tuned in the future to
* twice or so - we'll see) then it is not copied to tospace, but instead
* promoted to the second generation. If we are collecting generation 2 also,
* then objects that are alive in the second generation are simply marked.
* Since the second generation is managed as a set of sized pools, there is
* much less motivation for any kind of copying/compaction; the internal
* fragmentation that makes finding a right-sized gap problematic will not
* happen.
*
* Note that it adds the roots and processes them in phases, to try to avoid
* building up a huge worklist. */
void MVM_gc_collect(MVMThreadContext *tc, MVMuint8 what_to_do, MVMuint8 gen) {
/* Create a GC worklist. */
MVMGCWorklist *worklist = MVM_gc_worklist_create(tc, gen != MVMGCGenerations_Nursery);
/* Initialize work passing data structure. */
WorkToPass wtp;
wtp.num_target_threads = 0;
wtp.target_work = NULL;
/* If we're starting a run (as opposed to just coming back here to do a
* little more work we got after we first thought we were done...) */
if (what_to_do != MVMGCWhatToDo_InTray) {
/* Swap fromspace and tospace. */
void * fromspace = tc->nursery_tospace;
void * tospace = tc->nursery_fromspace;
tc->nursery_fromspace = fromspace;
tc->nursery_tospace = tospace;
/* Reset nursery allocation pointers to the new tospace. */
tc->nursery_alloc = tospace;
tc->nursery_alloc_limit = (char *)tc->nursery_alloc + MVM_NURSERY_SIZE;
MVM_gc_worklist_add(tc, worklist, &tc->thread_obj);
GCDEBUG_LOG(tc, MVM_GC_DEBUG_COLLECT, "Thread %d run %d : processing %d items from thread_obj\n", worklist->items);
process_worklist(tc, worklist, &wtp, gen);
/* Add permanent roots and process them; only one thread will do
* this, since they are instance-wide. */
if (what_to_do != MVMGCWhatToDo_NoInstance) {
MVM_gc_root_add_permanents_to_worklist(tc, worklist);
GCDEBUG_LOG(tc, MVM_GC_DEBUG_COLLECT, "Thread %d run %d : processing %d items from instance permanents\n", worklist->items);
process_worklist(tc, worklist, &wtp, gen);
MVM_gc_root_add_instance_roots_to_worklist(tc, worklist);
GCDEBUG_LOG(tc, MVM_GC_DEBUG_COLLECT, "Thread %d run %d : processing %d items from instance roots\n", worklist->items);
process_worklist(tc, worklist, &wtp, gen);
}
/* Add per-thread state to worklist and process it. */
MVM_gc_root_add_tc_roots_to_worklist(tc, worklist);
GCDEBUG_LOG(tc, MVM_GC_DEBUG_COLLECT, "Thread %d run %d : processing %d items from TC objects\n", worklist->items);
process_worklist(tc, worklist, &wtp, gen);
/* Add current frame to worklist. */
MVM_gc_worklist_add_frame(tc, worklist, tc->cur_frame);
GCDEBUG_LOG(tc, MVM_GC_DEBUG_COLLECT, "Thread %d run %d : processing %d items from current frame\n", worklist->items);
process_worklist(tc, worklist, &wtp, gen);
/* Add temporary roots and process them (these are per-thread). */
MVM_gc_root_add_temps_to_worklist(tc, worklist);
GCDEBUG_LOG(tc, MVM_GC_DEBUG_COLLECT, "Thread %d run %d : processing %d items from thread temps\n", worklist->items);
process_worklist(tc, worklist, &wtp, gen);
/* Add things that are roots for the first generation because they are
* pointed to by objects in the second generation and process them
* (also per-thread). Note we need not do this if we're doing a full
* collection anyway (in fact, we must not for correctness, otherwise
* the gen2 rooting keeps them alive forever). */
if (gen == MVMGCGenerations_Nursery) {
MVM_gc_root_add_gen2s_to_worklist(tc, worklist);
GCDEBUG_LOG(tc, MVM_GC_DEBUG_COLLECT, "Thread %d run %d : processing %d items from gen2 \n", worklist->items);
process_worklist(tc, worklist, &wtp, gen);
}
/* Find roots in frames and process them. */
if (tc->cur_frame) {
MVM_gc_worklist_add_frame(tc, worklist, tc->cur_frame);
GCDEBUG_LOG(tc, MVM_GC_DEBUG_COLLECT, "Thread %d run %d : processing %d items from cur_frame \n", worklist->items);
process_worklist(tc, worklist, &wtp, gen);
}
/* Process anything in the in-tray. */
add_in_tray_to_worklist(tc, worklist);
GCDEBUG_LOG(tc, MVM_GC_DEBUG_COLLECT, "Thread %d run %d : processing %d items from in tray \n", worklist->items);
process_worklist(tc, worklist, &wtp, gen);
/* At this point, we have probably done most of the work we will
* need to (only get more if another thread passes us more); zero
* out the remaining tospace. */
memset(tc->nursery_alloc, 0, (char *)tc->nursery_alloc_limit - (char *)tc->nursery_alloc);
}
else {
/* We just need to process anything in the in-tray. */
add_in_tray_to_worklist(tc, worklist);
GCDEBUG_LOG(tc, MVM_GC_DEBUG_COLLECT, "Thread %d run %d : processing %d items from in tray \n", worklist->items);
process_worklist(tc, worklist, &wtp, gen);
}
/* Destroy the worklist. */
MVM_gc_worklist_destroy(tc, worklist);
/* Pass any work for other threads we accumulated but that didn't trigger
* the work passing threshold, then cleanup work passing list. */
if (wtp.num_target_threads) {
pass_leftover_work(tc, &wtp);
free(wtp.target_work);
}
/* If it was a full collection, some of the things in gen2 that we root
* due to point to gen1 objects may be dead. */
if (gen != MVMGCGenerations_Nursery)
MVM_gc_root_gen2_cleanup(tc);
}
/* Does a garbage collection run. Exactly what it does is configured by the
* couple of arguments that it takes.
*
* The what_to_do argument specifies where it should look for things to add
* to the worklist: everywhere, just at thread local stuff, or just in the
* thread's in-tray.
*
* The gen argument specifies whether to collect the nursery or both of the
* generations. Nursery collection is done by semi-space copying. Once an
* object is seen/copied once in the nursery (may be tuned in the future to
* twice or so - we'll see) then it is not copied to tospace, but instead
* promoted to the second generation. If we are collecting generation 2 also,
* then objects that are alive in the second generation are simply marked.
* Since the second generation is managed as a set of sized pools, there is
* much less motivation for any kind of copying/compaction; the internal
* fragmentation that makes finding a right-sized gap problematic will not
* happen.
*
* Note that it adds the roots and processes them in phases, to try to avoid
* building up a huge worklist. */
void MVM_gc_collect(MVMThreadContext *tc, MVMuint8 what_to_do, MVMuint8 gen) {
/* Create a GC worklist. */
MVMGCWorklist *worklist = MVM_gc_worklist_create(tc, gen != MVMGCGenerations_Nursery, 0);
/* Initialize work passing data structure. */
WorkToPass wtp;
wtp.num_target_threads = 0;
wtp.target_work = NULL;
/* See what we need to work on this time. */
if (what_to_do == MVMGCWhatToDo_InTray) {
/* We just need to process anything in the in-tray. */
add_in_tray_to_worklist(tc, worklist);
GCDEBUG_LOG(tc, MVM_GC_DEBUG_COLLECT, "Thread %d run %d : processing %d items from in tray \n", worklist->items);
process_worklist(tc, worklist, &wtp, gen);
}
else if (what_to_do == MVMGCWhatToDo_Finalizing) {
/* Need to process the finalizing queue. */
MVMuint32 i;
for (i = 0; i < tc->num_finalizing; i++)
MVM_gc_worklist_add(tc, worklist, &(tc->finalizing[i]));
GCDEBUG_LOG(tc, MVM_GC_DEBUG_COLLECT, "Thread %d run %d : processing %d items from finalizing \n", worklist->items);
process_worklist(tc, worklist, &wtp, gen);
}
else {
/* Main collection run. Swap fromspace and tospace, allocating the
* new tospace if that didn't yet happen (we don't allocate it at
* startup, to cut memory use for threads that quit before a GC). */
void *fromspace = tc->nursery_tospace;
void *tospace = tc->nursery_fromspace;
if (!tospace)
tospace = MVM_calloc(1, MVM_NURSERY_SIZE);
tc->nursery_fromspace = fromspace;
tc->nursery_tospace = tospace;
/* Reset nursery allocation pointers to the new tospace. */
tc->nursery_alloc = tospace;
tc->nursery_alloc_limit = (char *)tc->nursery_alloc + MVM_NURSERY_SIZE;
/* Add permanent roots and process them; only one thread will do
* this, since they are instance-wide. */
if (what_to_do != MVMGCWhatToDo_NoInstance) {
MVM_gc_root_add_permanents_to_worklist(tc, worklist, NULL);
GCDEBUG_LOG(tc, MVM_GC_DEBUG_COLLECT, "Thread %d run %d : processing %d items from instance permanents\n", worklist->items);
process_worklist(tc, worklist, &wtp, gen);
MVM_gc_root_add_instance_roots_to_worklist(tc, worklist, NULL);
GCDEBUG_LOG(tc, MVM_GC_DEBUG_COLLECT, "Thread %d run %d : processing %d items from instance roots\n", worklist->items);
process_worklist(tc, worklist, &wtp, gen);
}
/* Add per-thread state to worklist and process it. */
MVM_gc_root_add_tc_roots_to_worklist(tc, worklist, NULL);
GCDEBUG_LOG(tc, MVM_GC_DEBUG_COLLECT, "Thread %d run %d : processing %d items from TC objects\n", worklist->items);
process_worklist(tc, worklist, &wtp, gen);
/* Add current frame to worklist. */
MVM_gc_worklist_add_frame(tc, worklist, tc->cur_frame);
GCDEBUG_LOG(tc, MVM_GC_DEBUG_COLLECT, "Thread %d run %d : processing %d items from current frame\n", worklist->items);
process_worklist(tc, worklist, &wtp, gen);
/* Add temporary roots and process them (these are per-thread). */
MVM_gc_root_add_temps_to_worklist(tc, worklist, NULL);
GCDEBUG_LOG(tc, MVM_GC_DEBUG_COLLECT, "Thread %d run %d : processing %d items from thread temps\n", worklist->items);
process_worklist(tc, worklist, &wtp, gen);
/* Add things that are roots for the first generation because they are
* pointed to by objects in the second generation and process them
* (also per-thread). Note we need not do this if we're doing a full
* collection anyway (in fact, we must not for correctness, otherwise
* the gen2 rooting keeps them alive forever). */
if (gen == MVMGCGenerations_Nursery) {
MVM_gc_root_add_gen2s_to_worklist(tc, worklist);
GCDEBUG_LOG(tc, MVM_GC_DEBUG_COLLECT, "Thread %d run %d : processing %d items from gen2 \n", worklist->items);
process_worklist(tc, worklist, &wtp, gen);
}
/* Process anything in the in-tray. */
add_in_tray_to_worklist(tc, worklist);
GCDEBUG_LOG(tc, MVM_GC_DEBUG_COLLECT, "Thread %d run %d : processing %d items from in tray \n", worklist->items);
process_worklist(tc, worklist, &wtp, gen);
/* At this point, we have probably done most of the work we will
* need to (only get more if another thread passes us more); zero
* out the remaining tospace. */
memset(tc->nursery_alloc, 0, (char *)tc->nursery_alloc_limit - (char *)tc->nursery_alloc);
}
/* Destroy the worklist. */
MVM_gc_worklist_destroy(tc, worklist);
/* Pass any work for other threads we accumulated but that didn't trigger
* the work passing threshold, then cleanup work passing list. */
if (wtp.num_target_threads) {
pass_leftover_work(tc, &wtp);
MVM_free(wtp.target_work);
}
}
/* Does a garbage collection run. Exactly what it does is configured by the
* couple of arguments that it takes.
*
* The what_to_do argument specifies where it should look for things to add
* to the worklist: everywhere, just at thread local stuff, or just in the
* thread's in-tray.
*
* The gen argument specifies whether to collect the nursery or both of the
* generations. Nursery collection is done by semi-space copying. Once an
* object is seen/copied once in the nursery (may be tuned in the future to
* twice or so - we'll see) then it is not copied to tospace, but instead
* promoted to the second generation. If we are collecting generation 2 also,
* then objects that are alive in the second generation are simply marked.
* Since the second generation is managed as a set of sized pools, there is
* much less motivation for any kind of copying/compaction; the internal
* fragmentation that makes finding a right-sized gap problematic will not
* happen.
*
* Note that it adds the roots and processes them in phases, to try to avoid
* building up a huge worklist. */
void MVM_gc_collect(MVMThreadContext *tc, MVMuint8 what_to_do, MVMuint8 gen) {
/* Create a GC worklist. */
MVMGCWorklist *worklist = MVM_gc_worklist_create(tc, gen != MVMGCGenerations_Nursery);
/* Initialize work passing data structure. */
WorkToPass wtp;
wtp.num_target_threads = 0;
wtp.target_work = NULL;
/* See what we need to work on this time. */
if (what_to_do == MVMGCWhatToDo_InTray) {
/* We just need to process anything in the in-tray. */
add_in_tray_to_worklist(tc, worklist);
GCDEBUG_LOG(tc, MVM_GC_DEBUG_COLLECT, "Thread %d run %d : processing %d items from in tray \n", worklist->items);
process_worklist(tc, worklist, &wtp, gen);
}
else if (what_to_do == MVMGCWhatToDo_Finalizing) {
/* Need to process the finalizing queue. */
MVMuint32 i;
for (i = 0; i < tc->num_finalizing; i++)
MVM_gc_worklist_add(tc, worklist, &(tc->finalizing[i]));
GCDEBUG_LOG(tc, MVM_GC_DEBUG_COLLECT, "Thread %d run %d : processing %d items from finalizing \n", worklist->items);
process_worklist(tc, worklist, &wtp, gen);
}
else {
/* Main collection run. The current tospace becomes fromspace, with
* the size of the current tospace becoming stashed as the size of
* that fromspace. */
void *old_fromspace = tc->nursery_fromspace;
MVMuint32 old_fromspace_size = tc->nursery_fromspace_size;
tc->nursery_fromspace = tc->nursery_tospace;
tc->nursery_fromspace_size = tc->nursery_tospace_size;
/* Decide on this threads's tospace size. If fromspace was already at
* the maximum nursery size, then that is the new tospace size. If
* not, then see if this thread caused the current GC run, and grant
* it a bigger tospace. Otherwise, new tospace size is left as the
* last tospace size. */
if (tc->nursery_tospace_size < MVM_NURSERY_SIZE) {
if (tc->instance->thread_to_blame_for_gc == tc)
tc->nursery_tospace_size *= 2;
}
/* If the old fromspace matches the target size, just re-use it. If
* not, free it and allocate a new tospace. */
if (old_fromspace_size == tc->nursery_tospace_size) {
tc->nursery_tospace = old_fromspace;
}
else {
MVM_free(old_fromspace);
tc->nursery_tospace = MVM_calloc(1, tc->nursery_tospace_size);
}
/* Reset nursery allocation pointers to the new tospace. */
tc->nursery_alloc = tc->nursery_tospace;
tc->nursery_alloc_limit = (char *)tc->nursery_tospace + tc->nursery_tospace_size;
/* Add permanent roots and process them; only one thread will do
* this, since they are instance-wide. */
if (what_to_do != MVMGCWhatToDo_NoInstance) {
MVM_gc_root_add_permanents_to_worklist(tc, worklist, NULL);
GCDEBUG_LOG(tc, MVM_GC_DEBUG_COLLECT, "Thread %d run %d : processing %d items from instance permanents\n", worklist->items);
process_worklist(tc, worklist, &wtp, gen);
MVM_gc_root_add_instance_roots_to_worklist(tc, worklist, NULL);
GCDEBUG_LOG(tc, MVM_GC_DEBUG_COLLECT, "Thread %d run %d : processing %d items from instance roots\n", worklist->items);
process_worklist(tc, worklist, &wtp, gen);
}
/* Add per-thread state to worklist and process it. */
MVM_gc_root_add_tc_roots_to_worklist(tc, worklist, NULL);
GCDEBUG_LOG(tc, MVM_GC_DEBUG_COLLECT, "Thread %d run %d : processing %d items from TC objects\n", worklist->items);
process_worklist(tc, worklist, &wtp, gen);
/* Walk current call stack, following caller chain until we reach a
* heap-allocated frame. Note that tc->cur_frame may itself be a heap
* frame, in which case we put it directly on the worklist as it can
* move. */
if (tc->cur_frame && MVM_FRAME_IS_ON_CALLSTACK(tc, tc->cur_frame)) {
MVMFrame *cur_frame = tc->cur_frame;
while (cur_frame && MVM_FRAME_IS_ON_CALLSTACK(tc, cur_frame)) {
MVM_gc_root_add_frame_roots_to_worklist(tc, worklist, cur_frame);
GCDEBUG_LOG(tc, MVM_GC_DEBUG_COLLECT, "Thread %d run %d : processing %d items from a stack frame\n", worklist->items);
process_worklist(tc, worklist, &wtp, gen);
cur_frame = cur_frame->caller;
}
}
else {
MVM_gc_worklist_add(tc, worklist, &tc->cur_frame);
GCDEBUG_LOG(tc, MVM_GC_DEBUG_COLLECT, "Thread %d run %d : processing %d items from current frame\n", worklist->items);
process_worklist(tc, worklist, &wtp, gen);
}
/* Add temporary roots and process them (these are per-thread). */
MVM_gc_root_add_temps_to_worklist(tc, worklist, NULL);
GCDEBUG_LOG(tc, MVM_GC_DEBUG_COLLECT, "Thread %d run %d : processing %d items from thread temps\n", worklist->items);
process_worklist(tc, worklist, &wtp, gen);
/* Add things that are roots for the first generation because they are
* pointed to by objects in the second generation and process them
* (also per-thread). Note we need not do this if we're doing a full
* collection anyway (in fact, we must not for correctness, otherwise
* the gen2 rooting keeps them alive forever). */
if (gen == MVMGCGenerations_Nursery) {
MVM_gc_root_add_gen2s_to_worklist(tc, worklist);
GCDEBUG_LOG(tc, MVM_GC_DEBUG_COLLECT, "Thread %d run %d : processing %d items from gen2 \n", worklist->items);
process_worklist(tc, worklist, &wtp, gen);
}
/* Process anything in the in-tray. */
add_in_tray_to_worklist(tc, worklist);
GCDEBUG_LOG(tc, MVM_GC_DEBUG_COLLECT, "Thread %d run %d : processing %d items from in tray \n", worklist->items);
process_worklist(tc, worklist, &wtp, gen);
/* At this point, we have probably done most of the work we will
* need to (only get more if another thread passes us more); zero
* out the remaining tospace. */
memset(tc->nursery_alloc, 0, (char *)tc->nursery_alloc_limit - (char *)tc->nursery_alloc);
}
/* Destroy the worklist. */
MVM_gc_worklist_destroy(tc, worklist);
/* Pass any work for other threads we accumulated but that didn't trigger
* the work passing threshold, then cleanup work passing list. */
if (wtp.num_target_threads) {
pass_leftover_work(tc, &wtp);
MVM_free(wtp.target_work);
}
}
