X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Frts%2FGC.c;h=883058234e181881c39554078a6fc094406a7f24;hb=a186d6f72aa221772ffeccb99c6c538c4505b0d7;hp=e0a665eb9c8eee9861798211a1b187f852be60c1;hpb=f3d40a6e45424480276d701f20b1ab4ea4278af4;p=ghc-hetmet.git diff --git a/ghc/rts/GC.c b/ghc/rts/GC.c index e0a665e..8830582 100644 --- a/ghc/rts/GC.c +++ b/ghc/rts/GC.c @@ -1,31 +1,32 @@ /* ----------------------------------------------------------------------------- - * $Id: GC.c,v 1.118 2001/08/08 14:14:08 simonmar Exp $ * - * (c) The GHC Team 1998-1999 + * (c) The GHC Team 1998-2003 * * Generational garbage collector * * ---------------------------------------------------------------------------*/ +#include "PosixSource.h" #include "Rts.h" #include "RtsFlags.h" #include "RtsUtils.h" +#include "Apply.h" #include "Storage.h" -#include "StoragePriv.h" +#include "LdvProfile.h" +#include "Updates.h" #include "Stats.h" #include "Schedule.h" -#include "SchedAPI.h" // for ReverCAFs prototype #include "Sanity.h" #include "BlockAlloc.h" #include "MBlock.h" -#include "Main.h" #include "ProfHeap.h" #include "SchedAPI.h" #include "Weak.h" -#include "StablePriv.h" #include "Prelude.h" #include "ParTicky.h" // ToDo: move into Rts.h #include "GCCompact.h" +#include "Signals.h" +#include "STM.h" #if defined(GRAN) || defined(PAR) # include "GranSimRts.h" # include "ParallelRts.h" @@ -41,6 +42,10 @@ #include "FrontPanel.h" #endif +#include "RetainerProfile.h" + +#include + /* STATIC OBJECT LIST. * * During GC: @@ -75,8 +80,8 @@ * We build up a static object list while collecting generations 0..N, * which is then appended to the static object list of generation N+1. */ -StgClosure* static_objects; // live static objects -StgClosure* scavenged_static_objects; // static objects scavenged so far +static StgClosure* static_objects; // live static objects +StgClosure* scavenged_static_objects; // static objects scavenged so far /* N is the oldest generation being collected, where the generations * are numbered starting at 0. A major GC (indicated by the major_gc @@ -95,12 +100,17 @@ static nat evac_gen; /* Weak pointers */ StgWeak *old_weak_ptr_list; // also pending finaliser list -static rtsBool weak_done; // all done for this pass + +/* Which stage of processing various kinds of weak pointer are we at? + * (see traverse_weak_ptr_list() below for discussion). + */ +typedef enum { WeakPtrs, WeakThreads, WeakDone } WeakStage; +static WeakStage weak_stage; /* List of all threads during GC */ static StgTSO *old_all_threads; -static StgTSO *resurrected_threads; +StgTSO *resurrected_threads; /* Flag indicating failure to evacuate an object to the desired * generation. @@ -109,39 +119,53 @@ static rtsBool failed_to_evac; /* Old to-space (used for two-space collector only) */ -bdescr *old_to_blocks; +static bdescr *old_to_blocks; /* 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 +static lnat new_blocks; // blocks allocated during this GC +static 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 +static lnat thunk_selector_depth = 0; +#define MAX_THUNK_SELECTOR_DEPTH 8 /* ----------------------------------------------------------------------------- Static function declarations -------------------------------------------------------------------------- */ +static bdescr * gc_alloc_block ( step *stp ); static void mark_root ( StgClosure **root ); -static StgClosure * evacuate ( StgClosure *q ); + +// Use a register argument for evacuate, if available. +#if __GNUC__ >= 2 +#define REGPARM1 __attribute__((regparm(1))) +#else +#define REGPARM1 +#endif + +REGPARM1 static StgClosure * evacuate (StgClosure *q); + static void zero_static_object_list ( StgClosure* first_static ); -static void zero_mutable_list ( StgMutClosure *first ); static rtsBool traverse_weak_ptr_list ( void ); static void mark_weak_ptr_list ( StgWeak **list ); -static void scavenge ( step * ); -static void scavenge_mark_stack ( void ); -static void scavenge_stack ( StgPtr p, StgPtr stack_end ); -static rtsBool scavenge_one ( StgPtr p ); -static void scavenge_large ( step * ); -static void scavenge_static ( void ); -static void scavenge_mutable_list ( generation *g ); -static void scavenge_mut_once_list ( generation *g ); -static void scavengeCAFs ( void ); +static StgClosure * eval_thunk_selector ( nat field, StgSelector * p ); + + +static void scavenge ( step * ); +static void scavenge_mark_stack ( void ); +static void scavenge_stack ( StgPtr p, StgPtr stack_end ); +static rtsBool scavenge_one ( StgPtr p ); +static void scavenge_large ( step * ); +static void scavenge_static ( void ); +static void scavenge_mutable_list ( generation *g ); + +static void scavenge_large_bitmap ( StgPtr p, + StgLargeBitmap *large_bitmap, + nat size ); #if 0 && defined(DEBUG) static void gcCAFs ( void ); @@ -164,57 +188,106 @@ static rtsBool mark_stack_overflowed; static bdescr *oldgen_scan_bd; static StgPtr oldgen_scan; -static inline rtsBool +STATIC_INLINE rtsBool mark_stack_empty(void) { return mark_sp == mark_stack; } -static inline rtsBool +STATIC_INLINE rtsBool mark_stack_full(void) { return mark_sp >= mark_splim; } -static inline void +STATIC_INLINE void reset_mark_stack(void) { mark_sp = mark_stack; } -static inline void +STATIC_INLINE void push_mark_stack(StgPtr p) { *mark_sp++ = p; } -static inline StgPtr +STATIC_INLINE StgPtr pop_mark_stack(void) { return *--mark_sp; } /* ----------------------------------------------------------------------------- + Allocate a new to-space block in the given step. + -------------------------------------------------------------------------- */ + +static bdescr * +gc_alloc_block(step *stp) +{ + bdescr *bd = allocBlock(); + bd->gen_no = stp->gen_no; + bd->step = stp; + bd->link = NULL; + + // blocks in to-space in generations up to and including N + // get the BF_EVACUATED flag. + if (stp->gen_no <= N) { + bd->flags = BF_EVACUATED; + } else { + bd->flags = 0; + } + + // Start a new to-space block, chain it on after the previous one. + if (stp->hp_bd == NULL) { + stp->hp_bd = bd; + } else { + stp->hp_bd->free = stp->hp; + stp->hp_bd->link = bd; + stp->hp_bd = bd; + } + + stp->hp = bd->start; + stp->hpLim = stp->hp + BLOCK_SIZE_W; + + stp->n_to_blocks++; + new_blocks++; + + return bd; +} + +/* ----------------------------------------------------------------------------- GarbageCollect - For garbage collecting generation N (and all younger generations): + Rough outline of the algorithm: for garbage collecting generation N + (and all younger generations): - follow all pointers in the root set. the root set includes all - mutable objects in all steps in all generations. + mutable objects in all generations (mutable_list). - for each pointer, evacuate the object it points to into either - + to-space in the next higher step in that generation, if one exists, - + if the object's generation == N, then evacuate it to the next - generation if one exists, or else to-space in the current - generation. - + if the object's generation < N, then evacuate it to to-space - in the next generation. + + + to-space of the step given by step->to, which is the next + highest step in this generation or the first step in the next + generation if this is the last step. + + + to-space of generations[evac_gen]->steps[0], if evac_gen != 0. + When we evacuate an object we attempt to evacuate + everything it points to into the same generation - this is + achieved by setting evac_gen to the desired generation. If + we can't do this, then an entry in the mut list has to + be made for the cross-generation pointer. + + + if the object is already in a generation > N, then leave + it alone. - repeatedly scavenge to-space from each step in each generation being collected until no more objects can be evacuated. - free from-space in each step, and set from-space = to-space. + Locks held: sched_mutex + -------------------------------------------------------------------------- */ void @@ -231,10 +304,18 @@ GarbageCollect ( void (*get_roots)(evac_fn), rtsBool force_major_gc ) #endif #if defined(DEBUG) && defined(GRAN) - IF_DEBUG(gc, belch("@@ Starting garbage collection at %ld (%lx)\n", + IF_DEBUG(gc, debugBelch("@@ Starting garbage collection at %ld (%lx)\n", Now, Now)); #endif +#if defined(RTS_USER_SIGNALS) + // block signals + blockUserSignals(); +#endif + + // tell the STM to discard any cached closures its hoping to re-use + stmPreGCHook(); + // tell the stats department that we've started a GC stat_startGC(); @@ -286,18 +367,12 @@ GarbageCollect ( void (*get_roots)(evac_fn), rtsBool force_major_gc ) static_objects = END_OF_STATIC_LIST; scavenged_static_objects = END_OF_STATIC_LIST; - /* zero the mutable list for the oldest generation (see comment by - * zero_mutable_list below). - */ - if (major_gc) { - zero_mutable_list(generations[RtsFlags.GcFlags.generations-1].mut_once_list); - } - /* Save the old to-space if we're doing a two-space collection */ if (RtsFlags.GcFlags.generations == 1) { old_to_blocks = g0s0->to_blocks; g0s0->to_blocks = NULL; + g0s0->n_to_blocks = 0; } /* Keep a count of how many new blocks we allocated during this GC @@ -305,12 +380,18 @@ GarbageCollect ( void (*get_roots)(evac_fn), rtsBool force_major_gc ) */ new_blocks = 0; - /* Initialise to-space in all the generations/steps that we're - * collecting. - */ + // Initialise to-space in all the generations/steps that we're + // collecting. + // for (g = 0; g <= N; g++) { - generations[g].mut_once_list = END_MUT_LIST; - generations[g].mut_list = END_MUT_LIST; + + // throw away the mutable list. Invariant: the mutable list + // always has at least one block; this means we can avoid a check for + // NULL in recordMutable(). + if (g != 0) { + freeChain(generations[g].mut_list); + generations[g].mut_list = allocBlock(); + } for (s = 0; s < generations[g].n_steps; s++) { @@ -319,31 +400,29 @@ GarbageCollect ( void (*get_roots)(evac_fn), rtsBool force_major_gc ) continue; } - /* Get a free block for to-space. Extra blocks will be chained on - * as necessary. - */ - bd = allocBlock(); stp = &generations[g].steps[s]; ASSERT(stp->gen_no == g); - ASSERT(stp->hp ? Bdescr(stp->hp)->step == stp : rtsTrue); - bd->gen_no = g; - bd->step = stp; - bd->link = NULL; - bd->flags = BF_EVACUATED; // it's a to-space block - stp->hp = bd->start; - stp->hpLim = stp->hp + BLOCK_SIZE_W; - stp->hp_bd = bd; + + // start a new to-space for this step. + stp->hp = NULL; + stp->hp_bd = NULL; + stp->to_blocks = NULL; + + // allocate the first to-space block; extra blocks will be + // chained on as necessary. + bd = gc_alloc_block(stp); stp->to_blocks = bd; - stp->n_to_blocks = 1; stp->scan = bd->start; stp->scan_bd = bd; + + // initialise the large object queues. stp->new_large_objects = NULL; stp->scavenged_large_objects = NULL; stp->n_scavenged_large_blocks = 0; - new_blocks++; + // mark the large objects as not evacuated yet for (bd = stp->large_objects; bd; bd = bd->link) { - bd->flags = BF_LARGE; + bd->flags &= ~BF_EVACUATED; } // for a compacted step, we need to allocate the bitmap @@ -360,17 +439,24 @@ GarbageCollect ( void (*get_roots)(evac_fn), rtsBool force_major_gc ) stp->bitmap = bitmap_bdescr; bitmap = bitmap_bdescr->start; - IF_DEBUG(gc, belch("bitmap_size: %d, bitmap: %p", + IF_DEBUG(gc, debugBelch("bitmap_size: %d, bitmap: %p", bitmap_size, bitmap);); // don't forget to fill it with zeros! memset(bitmap, 0, bitmap_size); - // for each block in this step, point to its bitmap from the + // For each block in this step, point to its bitmap from the // block descriptor. for (bd=stp->blocks; bd != NULL; bd = bd->link) { bd->u.bitmap = bitmap; bitmap += BLOCK_SIZE_W / (sizeof(W_)*BITS_PER_BYTE); + + // Also at this point we set the BF_COMPACTED flag + // for this block. The invariant is that + // BF_COMPACTED is always unset, except during GC + // when it is set on those blocks which will be + // compacted. + bd->flags |= BF_COMPACTED; } } } @@ -378,24 +464,16 @@ GarbageCollect ( void (*get_roots)(evac_fn), rtsBool force_major_gc ) } /* make sure the older generations have at least one block to - * allocate into (this makes things easier for copy(), see below. + * allocate into (this makes things easier for copy(), see below). */ for (g = N+1; g < RtsFlags.GcFlags.generations; g++) { for (s = 0; s < generations[g].n_steps; s++) { stp = &generations[g].steps[s]; if (stp->hp_bd == NULL) { ASSERT(stp->blocks == NULL); - bd = allocBlock(); - bd->gen_no = g; - bd->step = stp; - bd->link = NULL; - bd->flags = 0; // *not* a to-space block or a large object - stp->hp = bd->start; - stp->hpLim = stp->hp + BLOCK_SIZE_W; - stp->hp_bd = bd; + bd = gc_alloc_block(stp); 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. */ @@ -436,23 +514,12 @@ GarbageCollect ( void (*get_roots)(evac_fn), rtsBool force_major_gc ) int st; for (g = RtsFlags.GcFlags.generations-1; g > N; g--) { generations[g].saved_mut_list = generations[g].mut_list; - generations[g].mut_list = END_MUT_LIST; + generations[g].mut_list = allocBlock(); + // mut_list always has at least one block. } - // 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--) { - scavenge(&generations[g].steps[st]); - } - } - - for (g = RtsFlags.GcFlags.generations-1; g > N; g--) { - IF_PAR_DEBUG(verbose, - printMutableList(&generations[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--) { @@ -461,7 +528,10 @@ GarbageCollect ( void (*get_roots)(evac_fn), rtsBool force_major_gc ) } } - scavengeCAFs(); + /* follow roots from the CAF list (used by GHCi) + */ + evac_gen = 0; + markCAFs(mark_root); /* follow all the roots that the application knows about. */ @@ -489,7 +559,7 @@ GarbageCollect ( void (*get_roots)(evac_fn), rtsBool force_major_gc ) mark_weak_ptr_list(&weak_ptr_list); old_weak_ptr_list = weak_ptr_list; weak_ptr_list = NULL; - weak_done = rtsFalse; + weak_stage = WeakPtrs; /* The all_threads list is like the weak_ptr_list. * See traverse_weak_ptr_list() for the details. @@ -502,17 +572,6 @@ GarbageCollect ( void (*get_roots)(evac_fn), rtsBool force_major_gc ) */ markStablePtrTable(mark_root); -#ifdef INTERPRETER - { - /* ToDo: To fix the caf leak, we need to make the commented out - * parts of this code do something sensible - as described in - * the CAF document. - */ - extern void markHugsObjects(void); - markHugsObjects(); - } -#endif - /* ------------------------------------------------------------------------- * Repeatedly scavenge all the areas we know about until there's no * more scavenging to be done. @@ -573,12 +632,32 @@ GarbageCollect ( void (*get_roots)(evac_fn), rtsBool force_major_gc ) if (flag) { goto loop; } - // must be last... + // must be last... invariant is that everything is fully + // scavenged at this point. if (traverse_weak_ptr_list()) { // returns rtsTrue if evaced something goto loop; } } + /* Update the pointers from the "main thread" list - these are + * treated as weak pointers because we want to allow a main thread + * to get a BlockedOnDeadMVar exception in the same way as any other + * thread. Note that the threads should all have been retained by + * GC by virtue of being on the all_threads list, we're just + * updating pointers here. + */ + { + StgMainThread *m; + StgTSO *tso; + for (m = main_threads; m != NULL; m = m->link) { + tso = (StgTSO *) isAlive((StgClosure *)m->tso); + if (tso == NULL) { + barf("main thread has been GC'd"); + } + m->tso = tso; + } + } + #if defined(PAR) // Reconstruct the Global Address tables used in GUM rebuildGAtables(major_gc); @@ -593,12 +672,20 @@ GarbageCollect ( void (*get_roots)(evac_fn), rtsBool force_major_gc ) for (s = 0; s < generations[g].n_steps; s++) { stp = &generations[g].steps[s]; if (!(g == 0 && s == 0 && RtsFlags.GcFlags.generations > 1)) { + ASSERT(Bdescr(stp->hp) == stp->hp_bd); stp->hp_bd->free = stp->hp; - stp->hp_bd->link = NULL; } } } +#ifdef PROFILING + // We call processHeapClosureForDead() on every closure destroyed during + // the current garbage collection, so we invoke LdvCensusForDead(). + if (RtsFlags.ProfFlags.doHeapProfile == HEAP_BY_LDV + || RtsFlags.ProfFlags.bioSelector != NULL) + LdvCensusForDead(N); +#endif + // NO MORE EVACUATION AFTER THIS POINT! // Finally: compaction of the oldest generation. if (major_gc && oldest_gen->steps[0].is_compacted) { @@ -618,6 +705,14 @@ GarbageCollect ( void (*get_roots)(evac_fn), rtsBool force_major_gc ) generations[g].collections++; // for stats } + // Count the mutable list as bytes "copied" for the purposes of + // stats. Every mutable list is copied during every GC. + if (g > 0) { + for (bd = generations[g].mut_list; bd != NULL; bd = bd->link) { + copied += (bd->free - bd->start) * sizeof(StgWord); + } + } + for (s = 0; s < generations[g].n_steps; s++) { bdescr *next; stp = &generations[g].steps[s]; @@ -649,7 +744,7 @@ GarbageCollect ( void (*get_roots)(evac_fn), rtsBool force_major_gc ) // for a compacted step, just shift the new to-space // onto the front of the now-compacted existing blocks. for (bd = stp->to_blocks; bd != NULL; bd = bd->link) { - bd->flags &= ~BF_EVACUATED; // now from-space + bd->flags &= ~BF_EVACUATED; // now from-space } // tack the new blocks on the end of the existing blocks if (stp->blocks == NULL) { @@ -660,6 +755,11 @@ GarbageCollect ( void (*get_roots)(evac_fn), rtsBool force_major_gc ) if (next == NULL) { bd->link = stp->to_blocks; } + // NB. this step might not be compacted next + // time, so reset the BF_COMPACTED flags. + // They are set before GC if we're going to + // compact. (search for BF_COMPACTED above). + bd->flags &= ~BF_COMPACTED; } } // add the new blocks to the block tally @@ -669,7 +769,7 @@ GarbageCollect ( void (*get_roots)(evac_fn), rtsBool force_major_gc ) stp->blocks = stp->to_blocks; stp->n_blocks = stp->n_to_blocks; for (bd = stp->blocks; bd != NULL; bd = bd->link) { - bd->flags &= ~BF_EVACUATED; // now from-space + bd->flags &= ~BF_EVACUATED; // now from-space } } stp->to_blocks = NULL; @@ -709,6 +809,7 @@ GarbageCollect ( void (*get_roots)(evac_fn), rtsBool force_major_gc ) // add the new blocks we promoted during this GC stp->n_blocks += stp->n_to_blocks; + stp->n_to_blocks = 0; stp->n_large_blocks += stp->n_scavenged_large_blocks; } } @@ -740,15 +841,16 @@ GarbageCollect ( void (*get_roots)(evac_fn), rtsBool force_major_gc ) // Auto-enable compaction when the residency reaches a // certain percentage of the maximum heap size (default: 30%). - if (RtsFlags.GcFlags.compact || - (max > 0 && - oldest_gen->steps[0].n_blocks > - (RtsFlags.GcFlags.compactThreshold * max) / 100)) { + if (RtsFlags.GcFlags.generations > 1 && + (RtsFlags.GcFlags.compact || + (max > 0 && + oldest_gen->steps[0].n_blocks > + (RtsFlags.GcFlags.compactThreshold * max) / 100))) { oldest_gen->steps[0].is_compacted = 1; -// fprintf(stderr,"compaction: on\n", live); +// debugBelch("compaction: on\n", live); } else { oldest_gen->steps[0].is_compacted = 0; -// fprintf(stderr,"compaction: off\n", live); +// debugBelch("compaction: off\n", live); } // if we're going to go over the maximum heap size, reduce the @@ -756,6 +858,14 @@ GarbageCollect ( void (*get_roots)(evac_fn), rtsBool force_major_gc ) // different if compaction is turned on, because we don't need // to double the space required to collect the old generation. if (max != 0) { + + // this test is necessary to ensure that the calculations + // below don't have any negative results - we're working + // with unsigned values here. + if (max < min_alloc) { + heapOverflow(); + } + if (oldest_gen->steps[0].is_compacted) { if ( (size + (size - 1) * (gens - 2) * 2) + min_alloc > max ) { size = (max - min_alloc) / ((gens - 1) * 2 - 1); @@ -772,7 +882,7 @@ GarbageCollect ( void (*get_roots)(evac_fn), rtsBool force_major_gc ) } #if 0 - fprintf(stderr,"live: %d, min_alloc: %d, size : %d, max = %d\n", live, + debugBelch("live: %d, min_alloc: %d, size : %d, max = %d\n", live, min_alloc, size, max); #endif @@ -847,13 +957,14 @@ GarbageCollect ( void (*get_roots)(evac_fn), rtsBool force_major_gc ) */ blocks = g0s0->n_to_blocks; - if ( blocks * RtsFlags.GcFlags.oldGenFactor * 2 > - RtsFlags.GcFlags.maxHeapSize ) { + if ( RtsFlags.GcFlags.maxHeapSize != 0 && + blocks * RtsFlags.GcFlags.oldGenFactor * 2 > + RtsFlags.GcFlags.maxHeapSize ) { long adjusted_blocks; // signed on purpose int pc_free; adjusted_blocks = (RtsFlags.GcFlags.maxHeapSize - 2 * blocks); - IF_DEBUG(gc, belch("@@ Near maximum heap size of 0x%x blocks, blocks = %d, adjusted to %ld", RtsFlags.GcFlags.maxHeapSize, blocks, adjusted_blocks)); + IF_DEBUG(gc, debugBelch("@@ Near maximum heap size of 0x%x blocks, blocks = %d, adjusted to %ld", 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(); @@ -907,6 +1018,11 @@ GarbageCollect ( void (*get_roots)(evac_fn), rtsBool force_major_gc ) } resizeNursery((nat)blocks); + + } else { + // we might have added extra large blocks to the nursery, so + // resize back to minAllocAreaSize again. + resizeNursery(RtsFlags.GcFlags.minAllocAreaSize); } } @@ -915,6 +1031,12 @@ GarbageCollect ( void (*get_roots)(evac_fn), rtsBool force_major_gc ) if (major_gc) { gcCAFs(); } #endif +#ifdef PROFILING + // resetStaticObjectForRetainerProfiling() must be called before + // zeroing below. + resetStaticObjectForRetainerProfiling(); +#endif + // zero the scavenged static object list if (major_gc) { zero_static_object_list(scavenged_static_objects); @@ -923,11 +1045,15 @@ GarbageCollect ( void (*get_roots)(evac_fn), rtsBool force_major_gc ) // Reset the nursery resetNurseries(); + RELEASE_LOCK(&sched_mutex); + // start any pending finalizers scheduleFinalizers(old_weak_ptr_list); // send exceptions to any threads which were about to die resurrectThreads(resurrected_threads); + + ACQUIRE_LOCK(&sched_mutex); // Update the stable pointer hash table. updateStablePtrTable(major_gc); @@ -945,7 +1071,6 @@ GarbageCollect ( void (*get_roots)(evac_fn), rtsBool force_major_gc ) // restore enclosing cost centre #ifdef PROFILING - heapCensus(); CCCS = prev_CCS; #endif @@ -961,6 +1086,11 @@ GarbageCollect ( void (*get_roots)(evac_fn), rtsBool force_major_gc ) // ok, GC over: tell the stats department what happened. stat_endGC(allocated, collected, live, copied, N); +#if defined(RTS_USER_SIGNALS) + // unblock signals again + unblockUserSignals(); +#endif + //PAR_TICKY_TP(); } @@ -983,6 +1113,30 @@ GarbageCollect ( void (*get_roots)(evac_fn), rtsBool force_major_gc ) older generations than the one we're collecting. This could probably be optimised by keeping per-generation lists of weak pointers, but for a few weak pointers this scheme will work. + + There are three distinct stages to processing weak pointers: + + - weak_stage == WeakPtrs + + We process all the weak pointers whos keys are alive (evacuate + their values and finalizers), and repeat until we can find no new + live keys. If no live keys are found in this pass, then we + evacuate the finalizers of all the dead weak pointers in order to + run them. + + - weak_stage == WeakThreads + + Now, we discover which *threads* are still alive. Pointers to + threads from the all_threads and main thread lists are the + weakest of all: a pointers from the finalizer of a dead weak + pointer can keep a thread alive. Any threads found to be unreachable + are evacuated and placed on the resurrected_threads list so we + can send them a signal later. + + - weak_stage == WeakDone + + No more evacuation is done. + -------------------------------------------------------------------------- */ static rtsBool @@ -992,127 +1146,155 @@ traverse_weak_ptr_list(void) StgClosure *new; rtsBool flag = rtsFalse; - if (weak_done) { return rtsFalse; } - - /* doesn't matter where we evacuate values/finalizers to, since - * these pointers are treated as roots (iff the keys are alive). - */ - evac_gen = 0; - - last_w = &old_weak_ptr_list; - for (w = old_weak_ptr_list; w != NULL; w = next_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); + switch (weak_stage) { - /* Now, check whether the key is reachable. - */ - new = isAlive(w->key); - if (new != NULL) { - w->key = new; - // evacuate the value and finalizer - w->value = evacuate(w->value); - w->finalizer = evacuate(w->finalizer); - // remove this weak ptr from the old_weak_ptr list - *last_w = w->link; - // and put it on the new weak ptr list - next_w = w->link; - w->link = weak_ptr_list; - weak_ptr_list = w; - flag = rtsTrue; - IF_DEBUG(weak, belch("Weak pointer still alive at %p -> %p", w, w->key)); - continue; - } - else { - last_w = &(w->link); - next_w = w->link; - continue; - } - } + case WeakDone: + return rtsFalse; - /* 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; + case WeakPtrs: + /* doesn't matter where we evacuate values/finalizers to, since + * these pointers are treated as roots (iff the keys are alive). + */ + evac_gen = 0; + + last_w = &old_weak_ptr_list; + for (w = old_weak_ptr_list; w != NULL; w = next_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; + } + + switch (get_itbl(w)->type) { - prev = &old_all_threads; - for (t = old_all_threads; t != END_TSO_QUEUE; t = next) { + case EVACUATED: + next_w = (StgWeak *)((StgEvacuated *)w)->evacuee; + *last_w = next_w; + continue; - (StgClosure *)tmp = isAlive((StgClosure *)t); - - if (tmp != NULL) { - t = tmp; - } + case WEAK: + /* Now, check whether the key is reachable. + */ + new = isAlive(w->key); + if (new != NULL) { + w->key = new; + // evacuate the value and finalizer + w->value = evacuate(w->value); + w->finalizer = evacuate(w->finalizer); + // remove this weak ptr from the old_weak_ptr list + *last_w = w->link; + // and put it on the new weak ptr list + next_w = w->link; + w->link = weak_ptr_list; + weak_ptr_list = w; + flag = rtsTrue; + IF_DEBUG(weak, debugBelch("Weak pointer still alive at %p -> %p", + w, w->key)); + continue; + } + else { + last_w = &(w->link); + next_w = w->link; + continue; + } - ASSERT(get_itbl(t)->type == TSO); - switch (t->what_next) { - case ThreadRelocated: - next = t->link; - *prev = next; - continue; - case ThreadKilled: - case ThreadComplete: - // finshed or died. The thread might still be alive, but we - // don't keep it on the all_threads list. Don't forget to - // stub out its global_link field. - next = t->global_link; - t->global_link = END_TSO_QUEUE; - *prev = next; - continue; - default: - ; + default: + barf("traverse_weak_ptr_list: not WEAK"); + } } + + /* 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) { + for (w = old_weak_ptr_list; w; w = w->link) { + w->finalizer = evacuate(w->finalizer); + } - if (tmp == NULL) { - // not alive (yet): leave this thread on the old_all_threads list. - prev = &(t->global_link); - next = t->global_link; - } - else { - // alive: move this thread onto the all_threads list. - next = t->global_link; - t->global_link = all_threads; - all_threads = t; - *prev = next; + // Next, move to the WeakThreads stage after fully + // scavenging the finalizers we've just evacuated. + weak_stage = WeakThreads; } - } - } - /* 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) { - for (w = old_weak_ptr_list; w; w = w->link) { - w->finalizer = evacuate(w->finalizer); - } + return rtsTrue; - /* 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; + case WeakThreads: + /* 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) { + + tmp = (StgTSO *)isAlive((StgClosure *)t); + + if (tmp != NULL) { + t = tmp; + } + + ASSERT(get_itbl(t)->type == TSO); + switch (t->what_next) { + case ThreadRelocated: + next = t->link; + *prev = next; + continue; + case ThreadKilled: + case ThreadComplete: + // finshed or died. The thread might still be alive, but we + // don't keep it on the all_threads list. Don't forget to + // stub out its global_link field. + next = t->global_link; + t->global_link = END_TSO_QUEUE; + *prev = next; + continue; + default: + ; + } + + if (tmp == NULL) { + // not alive (yet): leave this thread on the + // old_all_threads list. + prev = &(t->global_link); + next = t->global_link; + } + else { + // alive: move this thread onto the all_threads list. + next = t->global_link; + t->global_link = all_threads; + all_threads = t; + *prev = next; + } + } } - } + + /* 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; + tmp = (StgTSO *)evacuate((StgClosure *)t); + tmp->global_link = resurrected_threads; + resurrected_threads = tmp; + } + } + + weak_stage = WeakDone; // *now* we're done, + return rtsTrue; // but one more round of scavenging, please - weak_done = rtsTrue; + default: + barf("traverse_weak_ptr_list"); + return rtsTrue; } - return rtsTrue; } /* ----------------------------------------------------------------------------- @@ -1135,7 +1317,10 @@ mark_weak_ptr_list ( StgWeak **list ) last_w = list; for (w = *list; w; w = w->link) { - (StgClosure *)w = evacuate((StgClosure *)w); + // w might be WEAK, EVACUATED, or DEAD_WEAK (actually CON_STATIC) here + ASSERT(w->header.info == &stg_DEAD_WEAK_info + || get_itbl(w)->type == WEAK || get_itbl(w)->type == EVACUATED); + w = (StgWeak *)evacuate((StgClosure *)w); *last_w = w; last_w = &(w->link); } @@ -1158,29 +1343,37 @@ isAlive(StgClosure *p) while (1) { + ASSERT(LOOKS_LIKE_CLOSURE_PTR(p)); info = get_itbl(p); - /* ToDo: for static closures, check the static link field. - * Problem here is that we sometimes don't set the link field, eg. - * for static closures with an empty SRT or CONSTR_STATIC_NOCAFs. - */ + // ignore static closures + // + // ToDo: for static closures, check the static link field. + // Problem here is that we sometimes don't set the link field, eg. + // for static closures with an empty SRT or CONSTR_STATIC_NOCAFs. + // + if (!HEAP_ALLOCED(p)) { + return p; + } - loop: - bd = Bdescr((P_)p); // ignore closures in generations that we're not collecting. - if (LOOKS_LIKE_STATIC(p) || bd->gen_no > N) { + bd = Bdescr((P_)p); + if (bd->gen_no > N) { + return p; + } + + // if it's a pointer into to-space, then we're done + if (bd->flags & BF_EVACUATED) { return p; } - // large objects have an evacuated flag + + // large objects use the evacuated flag if (bd->flags & BF_LARGE) { - if (bd->flags & BF_EVACUATED) { - return p; - } else { - return NULL; - } + return NULL; } + // check the mark bit for compacted steps - if (bd->step->is_compacted && is_marked((P_)p,bd)) { + if ((bd->flags & BF_COMPACTED) && is_marked((P_)p,bd)) { return p; } @@ -1202,8 +1395,9 @@ isAlive(StgClosure *p) case TSO: if (((StgTSO *)p)->what_next == ThreadRelocated) { p = (StgClosure *)((StgTSO *)p)->link; - goto loop; - } + continue; + } + return NULL; default: // dead. @@ -1218,41 +1412,26 @@ mark_root(StgClosure **root) *root = evacuate(*root); } -static void -addBlock(step *stp) -{ - bdescr *bd = allocBlock(); - bd->gen_no = stp->gen_no; - bd->step = stp; - - if (stp->gen_no <= N) { - bd->flags = BF_EVACUATED; - } else { - bd->flags = 0; - } - - 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->n_to_blocks++; - new_blocks++; -} - - -static __inline__ void +STATIC_INLINE void upd_evacuee(StgClosure *p, StgClosure *dest) { - p->header.info = &stg_EVACUATED_info; - ((StgEvacuated *)p)->evacuee = dest; + // Source object must be in from-space: + ASSERT((Bdescr((P_)p)->flags & BF_EVACUATED) == 0); + // not true: (ToDo: perhaps it should be) + // ASSERT(Bdescr((P_)dest)->flags & BF_EVACUATED); + SET_INFO(p, &stg_EVACUATED_info); + ((StgEvacuated *)p)->evacuee = dest; } -static __inline__ StgClosure * +STATIC_INLINE StgClosure * copy(StgClosure *src, nat size, step *stp) { P_ to, from, dest; +#ifdef PROFILING + // @LDV profiling + nat size_org = size; +#endif TICK_GC_WORDS_COPIED(size); /* Find out where we're going, using the handy "to" pointer in @@ -1272,7 +1451,7 @@ copy(StgClosure *src, nat size, step *stp) * necessary. */ if (stp->hp + size >= stp->hpLim) { - addBlock(stp); + gc_alloc_block(stp); } for(to = stp->hp, from = (P_)src; size>0; --size) { @@ -1282,6 +1461,11 @@ copy(StgClosure *src, nat size, step *stp) dest = stp->hp; stp->hp = to; upd_evacuee(src,(StgClosure *)dest); +#ifdef PROFILING + // We store the size of the just evacuated object in the LDV word so that + // the profiler can guess the position of the next object later. + SET_EVACUAEE_FOR_LDV(src, size_org); +#endif return (StgClosure *)dest; } @@ -1291,10 +1475,14 @@ copy(StgClosure *src, nat size, step *stp) */ -static __inline__ StgClosure * +static StgClosure * copyPart(StgClosure *src, nat size_to_reserve, nat size_to_copy, step *stp) { P_ dest, to, from; +#ifdef PROFILING + // @LDV profiling + nat size_to_copy_org = size_to_copy; +#endif TICK_GC_WORDS_COPIED(size_to_copy); if (stp->gen_no < evac_gen) { @@ -1306,7 +1494,7 @@ copyPart(StgClosure *src, nat size_to_reserve, nat size_to_copy, step *stp) } if (stp->hp + size_to_reserve >= stp->hpLim) { - addBlock(stp); + gc_alloc_block(stp); } for(to = stp->hp, from = (P_)src; size_to_copy>0; --size_to_copy) { @@ -1316,6 +1504,16 @@ copyPart(StgClosure *src, nat size_to_reserve, nat size_to_copy, step *stp) dest = stp->hp; stp->hp += size_to_reserve; upd_evacuee(src,(StgClosure *)dest); +#ifdef PROFILING + // We store the size of the just evacuated object in the LDV word so that + // the profiler can guess the position of the next object later. + // size_to_copy_org is wrong because the closure already occupies size_to_reserve + // words. + SET_EVACUAEE_FOR_LDV(src, size_to_reserve); + // fill the slop + if (size_to_reserve - size_to_copy_org > 0) + FILL_SLOP(stp->hp - 1, (int)(size_to_reserve - size_to_copy_org)); +#endif return (StgClosure *)dest; } @@ -1324,23 +1522,24 @@ copyPart(StgClosure *src, nat size_to_reserve, nat size_to_copy, step *stp) Evacuate a large object This just consists of removing the object from the (doubly-linked) - large_alloc_list, and linking it on to the (singly-linked) - new_large_objects list, from where it will be scavenged later. + step->large_objects list, and linking it on to the (singly-linked) + step->new_large_objects list, from where it will be scavenged later. Convention: bd->flags has BF_EVACUATED set for a large object that has been evacuated, or unset otherwise. -------------------------------------------------------------------------- */ -static inline void +STATIC_INLINE void evacuate_large(StgPtr p) { bdescr *bd = Bdescr(p); step *stp; - // should point to the beginning of the block - ASSERT(((W_)p & BLOCK_MASK) == 0); - + // object must be at the beginning of the block (or be a ByteArray) + ASSERT(get_itbl((StgClosure *)p)->type == ARR_WORDS || + (((W_)p & BLOCK_MASK) == 0)); + // already evacuated? if (bd->flags & BF_EVACUATED) { /* Don't forget to set the failed_to_evac flag if we didn't get @@ -1383,40 +1582,6 @@ evacuate_large(StgPtr p) } /* ----------------------------------------------------------------------------- - Adding a MUT_CONS to an older generation. - - This is necessary from time to time when we end up with an - old-to-new generation pointer in a non-mutable object. We defer - the promotion until the next GC. - -------------------------------------------------------------------------- */ - - -static StgClosure * -mkMutCons(StgClosure *ptr, generation *gen) -{ - StgMutVar *q; - step *stp; - - stp = &gen->steps[0]; - - /* chain a new block onto the to-space for the destination step if - * necessary. - */ - if (stp->hp + sizeofW(StgIndOldGen) >= stp->hpLim) { - addBlock(stp); - } - - q = (StgMutVar *)stp->hp; - stp->hp += sizeofW(StgMutVar); - - SET_HDR(q,&stg_MUT_CONS_info,CCS_GC); - q->var = ptr; - recordOldToNewPtrs((StgMutClosure *)q); - - return (StgClosure *)q; -} - -/* ----------------------------------------------------------------------------- Evacuate This is called (eventually) for every live object in the system. @@ -1439,9 +1604,26 @@ mkMutCons(StgClosure *ptr, generation *gen) if M < evac_gen set failed_to_evac flag to indicate that we didn't manage to evacuate this object into evac_gen. + + OPTIMISATION NOTES: + + evacuate() is the single most important function performance-wise + in the GC. Various things have been tried to speed it up, but as + far as I can tell the code generated by gcc 3.2 with -O2 is about + as good as it's going to get. We pass the argument to evacuate() + in a register using the 'regparm' attribute (see the prototype for + evacuate() near the top of this file). + + Changing evacuate() to take an (StgClosure **) rather than + returning the new pointer seems attractive, because we can avoid + writing back the pointer when it hasn't changed (eg. for a static + object, or an object in a generation > N). However, I tried it and + it doesn't help. One reason is that the (StgClosure **) pointer + gets spilled to the stack inside evacuate(), resulting in far more + extra reads/writes than we save. -------------------------------------------------------------------------- */ -static StgClosure * +REGPARM1 static StgClosure * evacuate(StgClosure *q) { StgClosure *to; @@ -1483,7 +1665,7 @@ loop: /* If the object is in a step that we're compacting, then we * need to use an alternative evacuate procedure. */ - if (bd->step->is_compacted) { + if (bd->flags & BF_COMPACTED) { if (!is_marked((P_)q,bd)) { mark((P_)q,bd); if (mark_stack_full()) { @@ -1502,16 +1684,14 @@ loop: #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)))); + ASSERT(LOOKS_LIKE_CLOSURE_PTR(q)); info = get_itbl(q); switch (info -> type) { case MUT_VAR: case MVAR: - to = copy(q,sizeW_fromITBL(info),stp); - return to; + return copy(q,sizeW_fromITBL(info),stp); case CONSTR_0_1: { @@ -1531,10 +1711,10 @@ loop: case FUN_1_0: case FUN_0_1: case CONSTR_1_0: + case THUNK_1_0: + case THUNK_0_1: return copy(q,sizeofW(StgHeader)+1,stp); - case THUNK_1_0: // here because of MIN_UPD_SIZE - case THUNK_0_1: case THUNK_1_1: case THUNK_0_2: case THUNK_2_0: @@ -1563,9 +1743,11 @@ loop: case WEAK: case FOREIGN: case STABLE_NAME: - case BCO: return copy(q,sizeW_fromITBL(info),stp); + case BCO: + return copy(q,bco_sizeW((StgBCO *)q),stp); + case CAF_BLACKHOLE: case SE_CAF_BLACKHOLE: case SE_BLACKHOLE: @@ -1578,139 +1760,32 @@ loop: case THUNK_SELECTOR: { - const StgInfoTable* selectee_info; - StgClosure* selectee = ((StgSelector*)q)->selectee; - - selector_loop: - selectee_info = get_itbl(selectee); - switch (selectee_info->type) { - case CONSTR: - case CONSTR_1_0: - case CONSTR_0_1: - case CONSTR_2_0: - case CONSTR_1_1: - case CONSTR_0_2: - case CONSTR_STATIC: - { - StgWord offset = info->layout.selector_offset; - - // check that the size is in range - ASSERT(offset < - (StgWord32)(selectee_info->layout.payload.ptrs + - selectee_info->layout.payload.nptrs)); + StgClosure *p; - // perform the selection! - q = selectee->payload[offset]; + if (thunk_selector_depth > MAX_THUNK_SELECTOR_DEPTH) { + return copy(q,THUNK_SELECTOR_sizeW(),stp); + } - /* if we're already in to-space, there's no need to continue - * with the evacuation, just update the source address with - * a pointer to the (evacuated) constructor field. - */ - if (HEAP_ALLOCED(q)) { - bdescr *bd = Bdescr((P_)q); - if (bd->flags & BF_EVACUATED) { - if (bd->gen_no < evac_gen) { - failed_to_evac = rtsTrue; - TICK_GC_FAILED_PROMOTION(); - } - return q; - } - } + p = eval_thunk_selector(info->layout.selector_offset, + (StgSelector *)q); - /* otherwise, carry on and evacuate this constructor field, - * (but not the constructor itself) - */ - goto loop; + if (p == NULL) { + return copy(q,THUNK_SELECTOR_sizeW(),stp); + } else { + // q is still BLACKHOLE'd. + thunk_selector_depth++; + p = evacuate(p); + thunk_selector_depth--; + upd_evacuee(q,p); +#ifdef PROFILING + // We store the size of the just evacuated object in the + // LDV word so that the profiler can guess the position of + // the next object later. + SET_EVACUAEE_FOR_LDV(q, THUNK_SELECTOR_sizeW()); +#endif + return p; } - - case IND: - case IND_STATIC: - case IND_PERM: - case IND_OLDGEN: - case IND_OLDGEN_PERM: - selectee = ((StgInd *)selectee)->indirectee; - goto selector_loop; - - case EVACUATED: - 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->flags & BF_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_2_0: - case THUNK_1_1: - case THUNK_0_2: - case THUNK_STATIC: - 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 %d", - (int)(selectee_info->type)); - } - } - return copy(q,THUNK_SELECTOR_sizeW(),stp); + } case IND: case IND_OLDGEN: @@ -1719,7 +1794,7 @@ loop: goto loop; case THUNK_STATIC: - if (info->srt_len > 0 && major_gc && + if (info->srt_bitmap != 0 && major_gc && THUNK_STATIC_LINK((StgClosure *)q) == NULL) { THUNK_STATIC_LINK((StgClosure *)q) = static_objects; static_objects = (StgClosure *)q; @@ -1727,7 +1802,7 @@ loop: return q; case FUN_STATIC: - if (info->srt_len > 0 && major_gc && + if (info->srt_bitmap != 0 && major_gc && FUN_STATIC_LINK((StgClosure *)q) == NULL) { FUN_STATIC_LINK((StgClosure *)q) = static_objects; static_objects = (StgClosure *)q; @@ -1771,17 +1846,19 @@ loop: case UPDATE_FRAME: case STOP_FRAME: case CATCH_FRAME: - case SEQ_FRAME: + case CATCH_STM_FRAME: + case CATCH_RETRY_FRAME: + case ATOMICALLY_FRAME: // shouldn't see these barf("evacuate: stack frame at %p\n", q); - case AP_UPD: case PAP: - /* PAPs and AP_UPDs are special - the payload is a copy of a chunk - * of stack, tagging and all. - */ + case AP: return copy(q,pap_sizeW((StgPAP*)q),stp); + case AP_STACK: + return copy(q,ap_stack_sizeW((StgAP_STACK*)q),stp); + case EVACUATED: /* Already evacuated, just return the forwarding address. * HOWEVER: if the requested destination generation (evac_gen) is @@ -1792,7 +1869,7 @@ loop: */ if (evac_gen > 0) { // optimisation StgClosure *p = ((StgEvacuated*)q)->evacuee; - if (Bdescr((P_)p)->gen_no < evac_gen) { + if (HEAP_ALLOCED(p) && Bdescr((P_)p)->gen_no < evac_gen) { failed_to_evac = rtsTrue; TICK_GC_FAILED_PROMOTION(); } @@ -1805,6 +1882,7 @@ loop: case MUT_ARR_PTRS: case MUT_ARR_PTRS_FROZEN: + case MUT_ARR_PTRS_FROZEN0: // just copy the block return copy(q,mut_arr_ptrs_sizeW((StgMutArrPtrs *)q),stp); @@ -1823,8 +1901,18 @@ loop: * list it contains. */ { - StgTSO *new_tso = (StgTSO *)copy((StgClosure *)tso,tso_sizeW(tso),stp); + StgTSO *new_tso; + StgPtr p, q; + + new_tso = (StgTSO *)copyPart((StgClosure *)tso, + tso_sizeW(tso), + sizeofW(StgTSO), stp); move_TSO(tso, new_tso); + for (p = tso->sp, q = new_tso->sp; + p < tso->stack+tso->stack_size;) { + *q++ = *p++; + } + return (StgClosure *)new_tso; } } @@ -1837,7 +1925,7 @@ loop: //ToDo: derive size etc from reverted IP //to = copy(q,size,stp); IF_DEBUG(gc, - belch("@@ evacuate: RBH %p (%s) to %p (%s)", + debugBelch("@@ evacuate: RBH %p (%s) to %p (%s)", q, info_type(q), to, info_type(to))); return to; } @@ -1846,7 +1934,7 @@ loop: ASSERT(sizeofW(StgBlockedFetch) >= MIN_NONUPD_SIZE); to = copy(q,sizeofW(StgBlockedFetch),stp); IF_DEBUG(gc, - belch("@@ evacuate: %p (%s) to %p (%s)", + debugBelch("@@ evacuate: %p (%s) to %p (%s)", q, info_type(q), to, info_type(to))); return to; @@ -1857,7 +1945,7 @@ loop: ASSERT(sizeofW(StgBlockedFetch) >= MIN_UPD_SIZE); to = copy(q,sizeofW(StgFetchMe),stp); IF_DEBUG(gc, - belch("@@ evacuate: %p (%s) to %p (%s)", + debugBelch("@@ evacuate: %p (%s) to %p (%s)", q, info_type(q), to, info_type(to))); return to; @@ -1865,11 +1953,23 @@ loop: ASSERT(sizeofW(StgBlockedFetch) >= MIN_UPD_SIZE); to = copy(q,sizeofW(StgFetchMeBlockingQueue),stp); IF_DEBUG(gc, - belch("@@ evacuate: %p (%s) to %p (%s)", + debugBelch("@@ evacuate: %p (%s) to %p (%s)", q, info_type(q), to, info_type(to))); return to; #endif + case TREC_HEADER: + return copy(q,sizeofW(StgTRecHeader),stp); + + case TVAR_WAIT_QUEUE: + return copy(q,sizeofW(StgTVarWaitQueue),stp); + + case TVAR: + return copy(q,sizeofW(StgTVar),stp); + + case TREC_CHUNK: + return copy(q,sizeofW(StgTRecChunk),stp); + default: barf("evacuate: strange closure type %d", (int)(info->type)); } @@ -1878,108 +1978,333 @@ loop: } /* ----------------------------------------------------------------------------- - move_TSO is called to update the TSO structure after it has been - moved from one place to another. + Evaluate a THUNK_SELECTOR if possible. + + returns: NULL if we couldn't evaluate this THUNK_SELECTOR, or + a closure pointer if we evaluated it and this is the result. Note + that "evaluating" the THUNK_SELECTOR doesn't necessarily mean + reducing it to HNF, just that we have eliminated the selection. + The result might be another thunk, or even another THUNK_SELECTOR. + + If the return value is non-NULL, the original selector thunk has + been BLACKHOLE'd, and should be updated with an indirection or a + forwarding pointer. If the return value is NULL, then the selector + thunk is unchanged. -------------------------------------------------------------------------- */ -void -move_TSO(StgTSO *src, StgTSO *dest) +static inline rtsBool +is_to_space ( StgClosure *p ) { - ptrdiff_t diff; + bdescr *bd; + + bd = Bdescr((StgPtr)p); + if (HEAP_ALLOCED(p) && + ((bd->flags & BF_EVACUATED) + || ((bd->flags & BF_COMPACTED) && + is_marked((P_)p,bd)))) { + return rtsTrue; + } else { + return rtsFalse; + } +} - // relocate the stack pointers... - diff = (StgPtr)dest - (StgPtr)src; // In *words* - dest->sp = (StgPtr)dest->sp + diff; - dest->su = (StgUpdateFrame *) ((P_)dest->su + diff); +static StgClosure * +eval_thunk_selector( nat field, StgSelector * p ) +{ + StgInfoTable *info; + const StgInfoTable *info_ptr; + StgClosure *selectee; + + selectee = p->selectee; - relocate_stack(dest, diff); -} + // Save the real info pointer (NOTE: not the same as get_itbl()). + info_ptr = p->header.info; -/* ----------------------------------------------------------------------------- - relocate_stack is called to update the linkage between - UPDATE_FRAMEs (and SEQ_FRAMEs etc.) when a stack is moved from one - place to another. - -------------------------------------------------------------------------- */ + // If the THUNK_SELECTOR is in a generation that we are not + // collecting, then bail out early. We won't be able to save any + // space in any case, and updating with an indirection is trickier + // in an old gen. + if (Bdescr((StgPtr)p)->gen_no > N) { + return NULL; + } -StgTSO * -relocate_stack(StgTSO *dest, ptrdiff_t diff) -{ - StgUpdateFrame *su; - StgCatchFrame *cf; - StgSeqFrame *sf; + // BLACKHOLE the selector thunk, since it is now under evaluation. + // This is important to stop us going into an infinite loop if + // this selector thunk eventually refers to itself. + SET_INFO(p,&stg_BLACKHOLE_info); + +selector_loop: + + // We don't want to end up in to-space, because this causes + // problems when the GC later tries to evacuate the result of + // eval_thunk_selector(). There are various ways this could + // happen: + // + // 1. following an IND_STATIC + // + // 2. when the old generation is compacted, the mark phase updates + // from-space pointers to be to-space pointers, and we can't + // reliably tell which we're following (eg. from an IND_STATIC). + // + // 3. compacting GC again: if we're looking at a constructor in + // the compacted generation, it might point directly to objects + // in to-space. We must bale out here, otherwise doing the selection + // will result in a to-space pointer being returned. + // + // (1) is dealt with using a BF_EVACUATED test on the + // selectee. (2) and (3): we can tell if we're looking at an + // object in the compacted generation that might point to + // to-space objects by testing that (a) it is BF_COMPACTED, (b) + // the compacted generation is being collected, and (c) the + // object is marked. Only a marked object may have pointers that + // point to to-space objects, because that happens when + // scavenging. + // + // The to-space test is now embodied in the in_to_space() inline + // function, as it is re-used below. + // + if (is_to_space(selectee)) { + goto bale_out; + } - su = dest->su; + info = get_itbl(selectee); + switch (info->type) { + case CONSTR: + case CONSTR_1_0: + case CONSTR_0_1: + case CONSTR_2_0: + case CONSTR_1_1: + case CONSTR_0_2: + case CONSTR_STATIC: + case CONSTR_NOCAF_STATIC: + // check that the size is in range + ASSERT(field < (StgWord32)(info->layout.payload.ptrs + + info->layout.payload.nptrs)); + + // Select the right field from the constructor, and check + // that the result isn't in to-space. It might be in + // to-space if, for example, this constructor contains + // pointers to younger-gen objects (and is on the mut-once + // list). + // + { + StgClosure *q; + q = selectee->payload[field]; + if (is_to_space(q)) { + goto bale_out; + } else { + return q; + } + } - while ((P_)su < dest->stack + dest->stack_size) { - switch (get_itbl(su)->type) { - - // GCC actually manages to common up these three cases! + case IND: + case IND_PERM: + case IND_OLDGEN: + case IND_OLDGEN_PERM: + case IND_STATIC: + selectee = ((StgInd *)selectee)->indirectee; + goto selector_loop; - case UPDATE_FRAME: - su->link = (StgUpdateFrame *) ((StgPtr)su->link + diff); - su = su->link; - continue; + case EVACUATED: + // We don't follow pointers into to-space; the constructor + // has already been evacuated, so we won't save any space + // leaks by evaluating this selector thunk anyhow. + break; - case CATCH_FRAME: - cf = (StgCatchFrame *)su; - cf->link = (StgUpdateFrame *) ((StgPtr)cf->link + diff); - su = cf->link; - continue; + case THUNK_SELECTOR: + { + StgClosure *val; - case SEQ_FRAME: - sf = (StgSeqFrame *)su; - sf->link = (StgUpdateFrame *) ((StgPtr)sf->link + diff); - su = sf->link; - continue; + // check that we don't recurse too much, re-using the + // depth bound also used in evacuate(). + if (thunk_selector_depth >= MAX_THUNK_SELECTOR_DEPTH) { + break; + } + thunk_selector_depth++; - case STOP_FRAME: - // all done! - break; + val = eval_thunk_selector(info->layout.selector_offset, + (StgSelector *)selectee); - default: - barf("relocate_stack %d", (int)(get_itbl(su)->type)); + thunk_selector_depth--; + + if (val == NULL) { + break; + } else { + // We evaluated this selector thunk, so update it with + // an indirection. NOTE: we don't use UPD_IND here, + // because we are guaranteed that p is in a generation + // that we are collecting, and we never want to put the + // indirection on a mutable list. +#ifdef PROFILING + // For the purposes of LDV profiling, we have destroyed + // the original selector thunk. + SET_INFO(p, info_ptr); + LDV_RECORD_DEAD_FILL_SLOP_DYNAMIC(selectee); +#endif + ((StgInd *)selectee)->indirectee = val; + SET_INFO(selectee,&stg_IND_info); + + // For the purposes of LDV profiling, we have created an + // indirection. + LDV_RECORD_CREATE(selectee); + + selectee = val; + goto selector_loop; + } + } + + case AP: + case AP_STACK: + case THUNK: + case THUNK_1_0: + case THUNK_0_1: + case THUNK_2_0: + case THUNK_1_1: + case THUNK_0_2: + case THUNK_STATIC: + case CAF_BLACKHOLE: + case SE_CAF_BLACKHOLE: + case SE_BLACKHOLE: + case BLACKHOLE: + case BLACKHOLE_BQ: +#if defined(PAR) + case RBH: + case BLOCKED_FETCH: +# ifdef DIST + case REMOTE_REF: +# endif + case FETCH_ME: + case FETCH_ME_BQ: +#endif + // not evaluated yet + break; + + default: + barf("eval_thunk_selector: strange selectee %d", + (int)(info->type)); } - break; - } - return dest; +bale_out: + // We didn't manage to evaluate this thunk; restore the old info pointer + SET_INFO(p, info_ptr); + return NULL; } +/* ----------------------------------------------------------------------------- + move_TSO is called to update the TSO structure after it has been + moved from one place to another. + -------------------------------------------------------------------------- */ + +void +move_TSO (StgTSO *src, StgTSO *dest) +{ + ptrdiff_t diff; + + // relocate the stack pointer... + diff = (StgPtr)dest - (StgPtr)src; // In *words* + dest->sp = (StgPtr)dest->sp + diff; +} +/* Similar to scavenge_large_bitmap(), but we don't write back the + * pointers we get back from evacuate(). + */ +static void +scavenge_large_srt_bitmap( StgLargeSRT *large_srt ) +{ + nat i, b, size; + StgWord bitmap; + StgClosure **p; + + b = 0; + bitmap = large_srt->l.bitmap[b]; + size = (nat)large_srt->l.size; + p = (StgClosure **)large_srt->srt; + for (i = 0; i < size; ) { + if ((bitmap & 1) != 0) { + evacuate(*p); + } + i++; + p++; + if (i % BITS_IN(W_) == 0) { + b++; + bitmap = large_srt->l.bitmap[b]; + } else { + bitmap = bitmap >> 1; + } + } +} -static inline void -scavenge_srt(const StgInfoTable *info) +/* evacuate the SRT. If srt_bitmap is zero, then there isn't an + * srt field in the info table. That's ok, because we'll + * never dereference it. + */ +STATIC_INLINE void +scavenge_srt (StgClosure **srt, nat srt_bitmap) { - StgClosure **srt, **srt_end; + nat bitmap; + StgClosure **p; - /* evacuate the SRT. If srt_len is zero, then there isn't an - * srt field in the info table. That's ok, because we'll - * never dereference it. - */ - srt = (StgClosure **)(info->srt); - srt_end = srt + info->srt_len; - for (; srt < srt_end; 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. - */ + bitmap = srt_bitmap; + p = srt; + + if (bitmap == (StgHalfWord)(-1)) { + scavenge_large_srt_bitmap( (StgLargeSRT *)srt ); + return; + } + + while (bitmap != 0) { + if ((bitmap & 1) != 0) { #ifdef ENABLE_WIN32_DLL_SUPPORT - if ( (unsigned long)(*srt) & 0x1 ) { - evacuate(*stgCast(StgClosure**,(stgCast(unsigned long, *srt) & ~0x1))); - } else { - 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. + if ( (unsigned long)(*srt) & 0x1 ) { + evacuate(*stgCast(StgClosure**,(stgCast(unsigned long, *srt) & ~0x1))); + } else { + evacuate(*p); + } #else - evacuate(*srt); + evacuate(*p); #endif + } + p++; + bitmap = bitmap >> 1; } } + +STATIC_INLINE void +scavenge_thunk_srt(const StgInfoTable *info) +{ + StgThunkInfoTable *thunk_info; + + thunk_info = itbl_to_thunk_itbl(info); + scavenge_srt((StgClosure **)GET_SRT(thunk_info), thunk_info->i.srt_bitmap); +} + +STATIC_INLINE void +scavenge_fun_srt(const StgInfoTable *info) +{ + StgFunInfoTable *fun_info; + + fun_info = itbl_to_fun_itbl(info); + scavenge_srt((StgClosure **)GET_FUN_SRT(fun_info), fun_info->i.srt_bitmap); +} + +STATIC_INLINE void +scavenge_ret_srt(const StgInfoTable *info) +{ + StgRetInfoTable *ret_info; + + ret_info = itbl_to_ret_itbl(info); + scavenge_srt((StgClosure **)GET_SRT(ret_info), ret_info->i.srt_bitmap); +} + /* ----------------------------------------------------------------------------- Scavenge a TSO. -------------------------------------------------------------------------- */ @@ -1987,24 +2312,111 @@ scavenge_srt(const StgInfoTable *info) 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 + // chase the link field for any TSOs on the same queue + tso->link = (StgTSO *)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 + || 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])); + ) { + tso->block_info.closure = evacuate(tso->block_info.closure); + } + if ( tso->blocked_exceptions != NULL ) { + tso->blocked_exceptions = + (StgTSO *)evacuate((StgClosure *)tso->blocked_exceptions); + } + + // scavange current transaction record + tso->trec = (StgTRecHeader *)evacuate((StgClosure *)tso->trec); + + // scavenge this thread's stack + scavenge_stack(tso->sp, &(tso->stack[tso->stack_size])); +} + +/* ----------------------------------------------------------------------------- + Blocks of function args occur on the stack (at the top) and + in PAPs. + -------------------------------------------------------------------------- */ + +STATIC_INLINE StgPtr +scavenge_arg_block (StgFunInfoTable *fun_info, StgClosure **args) +{ + StgPtr p; + StgWord bitmap; + nat size; + + p = (StgPtr)args; + switch (fun_info->f.fun_type) { + case ARG_GEN: + bitmap = BITMAP_BITS(fun_info->f.bitmap); + size = BITMAP_SIZE(fun_info->f.bitmap); + goto small_bitmap; + case ARG_GEN_BIG: + size = GET_FUN_LARGE_BITMAP(fun_info)->size; + scavenge_large_bitmap(p, GET_FUN_LARGE_BITMAP(fun_info), size); + p += size; + break; + default: + bitmap = BITMAP_BITS(stg_arg_bitmaps[fun_info->f.fun_type]); + size = BITMAP_SIZE(stg_arg_bitmaps[fun_info->f.fun_type]); + small_bitmap: + while (size > 0) { + if ((bitmap & 1) == 0) { + *p = (StgWord)(StgPtr)evacuate((StgClosure *)*p); + } + p++; + bitmap = bitmap >> 1; + size--; + } + break; + } + return p; +} + +STATIC_INLINE StgPtr +scavenge_PAP (StgPAP *pap) +{ + StgPtr p; + StgWord bitmap, size; + StgFunInfoTable *fun_info; + + pap->fun = evacuate(pap->fun); + fun_info = get_fun_itbl(pap->fun); + ASSERT(fun_info->i.type != PAP); + + p = (StgPtr)pap->payload; + size = pap->n_args; + + switch (fun_info->f.fun_type) { + case ARG_GEN: + bitmap = BITMAP_BITS(fun_info->f.bitmap); + goto small_bitmap; + case ARG_GEN_BIG: + scavenge_large_bitmap(p, GET_FUN_LARGE_BITMAP(fun_info), size); + p += size; + break; + case ARG_BCO: + scavenge_large_bitmap((StgPtr)pap->payload, BCO_BITMAP(pap->fun), size); + p += size; + break; + default: + bitmap = BITMAP_BITS(stg_arg_bitmaps[fun_info->f.fun_type]); + small_bitmap: + size = pap->n_args; + while (size > 0) { + if ((bitmap & 1) == 0) { + *p = (StgWord)(StgPtr)evacuate((StgClosure *)*p); + } + p++; + bitmap = bitmap >> 1; + size--; + } + break; + } + return p; } /* ----------------------------------------------------------------------------- @@ -2046,32 +2458,36 @@ scavenge(step *stp) continue; } + ASSERT(LOOKS_LIKE_CLOSURE_PTR(p)); info = get_itbl((StgClosure *)p); - ASSERT(p && (LOOKS_LIKE_GHC_INFO(info) || IS_HUGS_CONSTR_INFO(info))); + ASSERT(thunk_selector_depth == 0); + q = p; switch (info->type) { - + case MVAR: - /* treat MVars specially, because we don't want to evacuate the - * mut_link field in the middle of the closure. - */ { StgMVar *mvar = ((StgMVar *)p); evac_gen = 0; - (StgClosure *)mvar->head = evacuate((StgClosure *)mvar->head); - (StgClosure *)mvar->tail = evacuate((StgClosure *)mvar->tail); - (StgClosure *)mvar->value = evacuate((StgClosure *)mvar->value); + mvar->head = (StgTSO *)evacuate((StgClosure *)mvar->head); + mvar->tail = (StgTSO *)evacuate((StgClosure *)mvar->tail); + mvar->value = evacuate((StgClosure *)mvar->value); evac_gen = saved_evac_gen; - recordMutable((StgMutClosure *)mvar); - failed_to_evac = rtsFalse; // mutable. + failed_to_evac = rtsTrue; // mutable. p += sizeofW(StgMVar); break; } - case THUNK_2_0: case FUN_2_0: - scavenge_srt(info); + scavenge_fun_srt(info); + ((StgClosure *)p)->payload[1] = evacuate(((StgClosure *)p)->payload[1]); + ((StgClosure *)p)->payload[0] = evacuate(((StgClosure *)p)->payload[0]); + p += sizeofW(StgHeader) + 2; + break; + + case THUNK_2_0: + scavenge_thunk_srt(info); case CONSTR_2_0: ((StgClosure *)p)->payload[1] = evacuate(((StgClosure *)p)->payload[1]); ((StgClosure *)p)->payload[0] = evacuate(((StgClosure *)p)->payload[0]); @@ -2079,92 +2495,114 @@ scavenge(step *stp) break; case THUNK_1_0: - scavenge_srt(info); + scavenge_thunk_srt(info); ((StgClosure *)p)->payload[0] = evacuate(((StgClosure *)p)->payload[0]); - p += sizeofW(StgHeader) + 2; // MIN_UPD_SIZE + p += sizeofW(StgHeader) + 1; break; case FUN_1_0: - scavenge_srt(info); + scavenge_fun_srt(info); case CONSTR_1_0: ((StgClosure *)p)->payload[0] = evacuate(((StgClosure *)p)->payload[0]); p += sizeofW(StgHeader) + 1; break; case THUNK_0_1: - scavenge_srt(info); - p += sizeofW(StgHeader) + 2; // MIN_UPD_SIZE + scavenge_thunk_srt(info); + p += sizeofW(StgHeader) + 1; break; case FUN_0_1: - scavenge_srt(info); + scavenge_fun_srt(info); case CONSTR_0_1: p += sizeofW(StgHeader) + 1; break; case THUNK_0_2: + scavenge_thunk_srt(info); + p += sizeofW(StgHeader) + 2; + break; + case FUN_0_2: - scavenge_srt(info); + scavenge_fun_srt(info); case CONSTR_0_2: p += sizeofW(StgHeader) + 2; break; case THUNK_1_1: + scavenge_thunk_srt(info); + ((StgClosure *)p)->payload[0] = evacuate(((StgClosure *)p)->payload[0]); + p += sizeofW(StgHeader) + 2; + break; + case FUN_1_1: - scavenge_srt(info); + scavenge_fun_srt(info); case CONSTR_1_1: ((StgClosure *)p)->payload[0] = evacuate(((StgClosure *)p)->payload[0]); p += sizeofW(StgHeader) + 2; break; case FUN: + scavenge_fun_srt(info); + goto gen_obj; + case THUNK: - scavenge_srt(info); + scavenge_thunk_srt(info); // fall through + gen_obj: case CONSTR: case WEAK: case FOREIGN: case STABLE_NAME: - case BCO: { StgPtr end; end = (P_)((StgClosure *)p)->payload + info->layout.payload.ptrs; for (p = (P_)((StgClosure *)p)->payload; p < end; p++) { - (StgClosure *)*p = evacuate((StgClosure *)*p); + *p = (StgWord)(StgPtr)evacuate((StgClosure *)*p); } p += info->layout.payload.nptrs; break; } + case BCO: { + StgBCO *bco = (StgBCO *)p; + bco->instrs = (StgArrWords *)evacuate((StgClosure *)bco->instrs); + bco->literals = (StgArrWords *)evacuate((StgClosure *)bco->literals); + bco->ptrs = (StgMutArrPtrs *)evacuate((StgClosure *)bco->ptrs); + bco->itbls = (StgArrWords *)evacuate((StgClosure *)bco->itbls); + p += bco_sizeW(bco); + break; + } + case IND_PERM: - if (stp->gen_no != 0) { - SET_INFO(((StgClosure *)p), &stg_IND_OLDGEN_PERM_info); - } + if (stp->gen->no != 0) { +#ifdef PROFILING + // @LDV profiling + // No need to call LDV_recordDead_FILL_SLOP_DYNAMIC() because an + // IND_OLDGEN_PERM closure is larger than an IND_PERM closure. + LDV_recordDead((StgClosure *)p, sizeofW(StgInd)); +#endif + // + // Todo: maybe use SET_HDR() and remove LDV_RECORD_CREATE()? + // + SET_INFO(((StgClosure *)p), &stg_IND_OLDGEN_PERM_info); + + // We pretend that p has just been created. + LDV_RECORD_CREATE((StgClosure *)p); + } // 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); + ((StgInd *)p)->indirectee = evacuate(((StgInd *)p)->indirectee); + p += sizeofW(StgInd); break; case MUT_VAR: evac_gen = 0; ((StgMutVar *)p)->var = evacuate(((StgMutVar *)p)->var); evac_gen = saved_evac_gen; - recordMutable((StgMutClosure *)p); - failed_to_evac = rtsFalse; // mutable anyhow - p += sizeofW(StgMutVar); - break; - - case MUT_CONS: - // ignore these - failed_to_evac = rtsFalse; // mutable anyhow + failed_to_evac = rtsTrue; // mutable anyhow p += sizeofW(StgMutVar); break; @@ -2178,10 +2616,9 @@ scavenge(step *stp) case BLACKHOLE_BQ: { StgBlockingQueue *bh = (StgBlockingQueue *)p; - (StgClosure *)bh->blocking_queue = - evacuate((StgClosure *)bh->blocking_queue); - recordMutable((StgMutClosure *)bh); - failed_to_evac = rtsFalse; + bh->blocking_queue = + (StgTSO *)evacuate((StgClosure *)bh->blocking_queue); + failed_to_evac = rtsTrue; p += BLACKHOLE_sizeW(); break; } @@ -2194,22 +2631,24 @@ scavenge(step *stp) break; } - case AP_UPD: // same as PAPs - case PAP: - /* Treat a PAP just like a section of stack, not forgetting to - * evacuate the function pointer too... - */ - { - StgPAP* pap = (StgPAP *)p; + // A chunk of stack saved in a heap object + case AP_STACK: + { + StgAP_STACK *ap = (StgAP_STACK *)p; - pap->fun = evacuate(pap->fun); - scavenge_stack((P_)pap->payload, (P_)pap->payload + pap->n_args); - p += pap_sizeW(pap); + ap->fun = evacuate(ap->fun); + scavenge_stack((StgPtr)ap->payload, (StgPtr)ap->payload + ap->size); + p = (StgPtr)ap->payload + ap->size; break; } - - case ARR_WORDS: - // nothing to follow + + case PAP: + case AP: + p = scavenge_PAP((StgPAP *)p); + break; + + case ARR_WORDS: + // nothing to follow p += arr_words_sizeW((StgArrWords *)p); break; @@ -2221,22 +2660,22 @@ scavenge(step *stp) evac_gen = 0; // repeatedly mutable next = p + mut_arr_ptrs_sizeW((StgMutArrPtrs*)p); for (p = (P_)((StgMutArrPtrs *)p)->payload; p < next; p++) { - (StgClosure *)*p = evacuate((StgClosure *)*p); + *p = (StgWord)(StgPtr)evacuate((StgClosure *)*p); } evac_gen = saved_evac_gen; - recordMutable((StgMutClosure *)q); - failed_to_evac = rtsFalse; // mutable anyhow. + failed_to_evac = rtsTrue; // mutable anyhow. break; } case MUT_ARR_PTRS_FROZEN: + case MUT_ARR_PTRS_FROZEN0: // follow everything { StgPtr next; next = p + mut_arr_ptrs_sizeW((StgMutArrPtrs*)p); for (p = (P_)((StgMutArrPtrs *)p)->payload; p < next; p++) { - (StgClosure *)*p = evacuate((StgClosure *)*p); + *p = (StgWord)(StgPtr)evacuate((StgClosure *)*p); } // it's tempting to recordMutable() if failed_to_evac is // false, but that breaks some assumptions (eg. every @@ -2251,8 +2690,7 @@ scavenge(step *stp) evac_gen = 0; scavengeTSO(tso); evac_gen = saved_evac_gen; - recordMutable((StgMutClosure *)tso); - failed_to_evac = rtsFalse; // mutable anyhow. + failed_to_evac = rtsTrue; // mutable anyhow. p += tso_sizeW(tso); break; } @@ -2268,10 +2706,9 @@ scavenge(step *stp) StgRBH *rbh = (StgRBH *)p; (StgClosure *)rbh->blocking_queue = evacuate((StgClosure *)rbh->blocking_queue); - recordMutable((StgMutClosure *)to); - failed_to_evac = rtsFalse; // mutable anyhow. + failed_to_evac = rtsTrue; // mutable anyhow. IF_DEBUG(gc, - belch("@@ scavenge: RBH %p (%s) (new blocking_queue link=%p)", + debugBelch("@@ 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(); @@ -2287,12 +2724,8 @@ scavenge(step *stp) // 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", + debugBelch("@@ 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); @@ -2311,30 +2744,84 @@ scavenge(step *stp) 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", + debugBelch("@@ scavenge: %p (%s) exciting, isn't it", p, info_type((StgClosure *)p))); p += sizeofW(StgFetchMeBlockingQueue); break; } #endif + case TVAR_WAIT_QUEUE: + { + StgTVarWaitQueue *wq = ((StgTVarWaitQueue *) p); + evac_gen = 0; + wq->waiting_tso = (StgTSO *)evacuate((StgClosure*)wq->waiting_tso); + wq->next_queue_entry = (StgTVarWaitQueue *)evacuate((StgClosure*)wq->next_queue_entry); + wq->prev_queue_entry = (StgTVarWaitQueue *)evacuate((StgClosure*)wq->prev_queue_entry); + evac_gen = saved_evac_gen; + failed_to_evac = rtsTrue; // mutable + p += sizeofW(StgTVarWaitQueue); + break; + } + + case TVAR: + { + StgTVar *tvar = ((StgTVar *) p); + evac_gen = 0; + tvar->current_value = evacuate((StgClosure*)tvar->current_value); + tvar->first_wait_queue_entry = (StgTVarWaitQueue *)evacuate((StgClosure*)tvar->first_wait_queue_entry); + evac_gen = saved_evac_gen; + failed_to_evac = rtsTrue; // mutable + p += sizeofW(StgTVar); + break; + } + + case TREC_HEADER: + { + StgTRecHeader *trec = ((StgTRecHeader *) p); + evac_gen = 0; + trec->enclosing_trec = (StgTRecHeader *)evacuate((StgClosure*)trec->enclosing_trec); + trec->current_chunk = (StgTRecChunk *)evacuate((StgClosure*)trec->current_chunk); + evac_gen = saved_evac_gen; + failed_to_evac = rtsTrue; // mutable + p += sizeofW(StgTRecHeader); + break; + } + + case TREC_CHUNK: + { + StgWord i; + StgTRecChunk *tc = ((StgTRecChunk *) p); + TRecEntry *e = &(tc -> entries[0]); + evac_gen = 0; + tc->prev_chunk = (StgTRecChunk *)evacuate((StgClosure*)tc->prev_chunk); + for (i = 0; i < tc -> next_entry_idx; i ++, e++ ) { + e->tvar = (StgTVar *)evacuate((StgClosure*)e->tvar); + e->expected_value = evacuate((StgClosure*)e->expected_value); + e->new_value = evacuate((StgClosure*)e->new_value); + } + evac_gen = saved_evac_gen; + failed_to_evac = rtsTrue; // mutable + p += sizeofW(StgTRecChunk); + break; + } + default: barf("scavenge: unimplemented/strange closure type %d @ %p", info->type, p); } - /* If we didn't manage to promote all the objects pointed to by - * the current object, then we have to designate this object as - * mutable (because it contains old-to-new generation pointers). + /* + * We need to record the current object on the mutable list if + * (a) It is actually mutable, or + * (b) It contains pointers to a younger generation. + * Case (b) arises if we didn't manage to promote everything that + * the current object points to into the current generation. */ if (failed_to_evac) { failed_to_evac = rtsFalse; - mkMutCons((StgClosure *)q, &generations[evac_gen]); + recordMutableGen((StgClosure *)q, stp->gen); } } @@ -2364,30 +2851,32 @@ linear_scan: while (!mark_stack_empty()) { p = pop_mark_stack(); + ASSERT(LOOKS_LIKE_CLOSURE_PTR(p)); info = get_itbl((StgClosure *)p); - ASSERT(p && (LOOKS_LIKE_GHC_INFO(info) || IS_HUGS_CONSTR_INFO(info))); q = p; switch (info->type) { case MVAR: - /* treat MVars specially, because we don't want to evacuate the - * mut_link field in the middle of the closure. - */ { StgMVar *mvar = ((StgMVar *)p); evac_gen = 0; - (StgClosure *)mvar->head = evacuate((StgClosure *)mvar->head); - (StgClosure *)mvar->tail = evacuate((StgClosure *)mvar->tail); - (StgClosure *)mvar->value = evacuate((StgClosure *)mvar->value); + mvar->head = (StgTSO *)evacuate((StgClosure *)mvar->head); + mvar->tail = (StgTSO *)evacuate((StgClosure *)mvar->tail); + mvar->value = evacuate((StgClosure *)mvar->value); evac_gen = saved_evac_gen; - failed_to_evac = rtsFalse; // mutable. + failed_to_evac = rtsTrue; // mutable. break; } case FUN_2_0: + scavenge_fun_srt(info); + ((StgClosure *)p)->payload[1] = evacuate(((StgClosure *)p)->payload[1]); + ((StgClosure *)p)->payload[0] = evacuate(((StgClosure *)p)->payload[0]); + break; + case THUNK_2_0: - scavenge_srt(info); + scavenge_thunk_srt(info); case CONSTR_2_0: ((StgClosure *)p)->payload[1] = evacuate(((StgClosure *)p)->payload[1]); ((StgClosure *)p)->payload[0] = evacuate(((StgClosure *)p)->payload[0]); @@ -2395,9 +2884,13 @@ linear_scan: case FUN_1_0: case FUN_1_1: + scavenge_fun_srt(info); + ((StgClosure *)p)->payload[0] = evacuate(((StgClosure *)p)->payload[0]); + break; + case THUNK_1_0: case THUNK_1_1: - scavenge_srt(info); + scavenge_thunk_srt(info); case CONSTR_1_0: case CONSTR_1_1: ((StgClosure *)p)->payload[0] = evacuate(((StgClosure *)p)->payload[0]); @@ -2405,33 +2898,50 @@ linear_scan: case FUN_0_1: case FUN_0_2: + scavenge_fun_srt(info); + break; + case THUNK_0_1: case THUNK_0_2: - scavenge_srt(info); + scavenge_thunk_srt(info); + break; + case CONSTR_0_1: case CONSTR_0_2: break; case FUN: + scavenge_fun_srt(info); + goto gen_obj; + case THUNK: - scavenge_srt(info); + scavenge_thunk_srt(info); // fall through + gen_obj: case CONSTR: case WEAK: case FOREIGN: case STABLE_NAME: - case BCO: { StgPtr end; end = (P_)((StgClosure *)p)->payload + info->layout.payload.ptrs; for (p = (P_)((StgClosure *)p)->payload; p < end; p++) { - (StgClosure *)*p = evacuate((StgClosure *)*p); + *p = (StgWord)(StgPtr)evacuate((StgClosure *)*p); } break; } + case BCO: { + StgBCO *bco = (StgBCO *)p; + bco->instrs = (StgArrWords *)evacuate((StgClosure *)bco->instrs); + bco->literals = (StgArrWords *)evacuate((StgClosure *)bco->literals); + bco->ptrs = (StgMutArrPtrs *)evacuate((StgClosure *)bco->ptrs); + bco->itbls = (StgArrWords *)evacuate((StgClosure *)bco->itbls); + break; + } + case IND_PERM: // don't need to do anything here: the only possible case // is that we're in a 1-space compacting collector, with @@ -2440,24 +2950,15 @@ linear_scan: case IND_OLDGEN: case IND_OLDGEN_PERM: - ((StgIndOldGen *)p)->indirectee = - evacuate(((StgIndOldGen *)p)->indirectee); - if (failed_to_evac) { - recordOldToNewPtrs((StgMutClosure *)p); - } - failed_to_evac = rtsFalse; + ((StgInd *)p)->indirectee = + evacuate(((StgInd *)p)->indirectee); break; case MUT_VAR: evac_gen = 0; ((StgMutVar *)p)->var = evacuate(((StgMutVar *)p)->var); evac_gen = saved_evac_gen; - failed_to_evac = rtsFalse; - break; - - case MUT_CONS: - // ignore these - failed_to_evac = rtsFalse; + failed_to_evac = rtsTrue; break; case CAF_BLACKHOLE: @@ -2470,9 +2971,9 @@ linear_scan: case BLACKHOLE_BQ: { StgBlockingQueue *bh = (StgBlockingQueue *)p; - (StgClosure *)bh->blocking_queue = - evacuate((StgClosure *)bh->blocking_queue); - failed_to_evac = rtsFalse; + bh->blocking_queue = + (StgTSO *)evacuate((StgClosure *)bh->blocking_queue); + failed_to_evac = rtsTrue; break; } @@ -2483,18 +2984,20 @@ linear_scan: break; } - case AP_UPD: // same as PAPs - case PAP: - /* Treat a PAP just like a section of stack, not forgetting to - * evacuate the function pointer too... - */ - { - StgPAP* pap = (StgPAP *)p; + // A chunk of stack saved in a heap object + case AP_STACK: + { + StgAP_STACK *ap = (StgAP_STACK *)p; - pap->fun = evacuate(pap->fun); - scavenge_stack((P_)pap->payload, (P_)pap->payload + pap->n_args); + ap->fun = evacuate(ap->fun); + scavenge_stack((StgPtr)ap->payload, (StgPtr)ap->payload + ap->size); break; } + + case PAP: + case AP: + scavenge_PAP((StgPAP *)p); + break; case MUT_ARR_PTRS: // follow everything @@ -2504,21 +3007,22 @@ linear_scan: evac_gen = 0; // repeatedly mutable next = p + mut_arr_ptrs_sizeW((StgMutArrPtrs*)p); for (p = (P_)((StgMutArrPtrs *)p)->payload; p < next; p++) { - (StgClosure *)*p = evacuate((StgClosure *)*p); + *p = (StgWord)(StgPtr)evacuate((StgClosure *)*p); } evac_gen = saved_evac_gen; - failed_to_evac = rtsFalse; // mutable anyhow. + failed_to_evac = rtsTrue; // mutable anyhow. break; } case MUT_ARR_PTRS_FROZEN: + case MUT_ARR_PTRS_FROZEN0: // follow everything { StgPtr next; next = p + mut_arr_ptrs_sizeW((StgMutArrPtrs*)p); for (p = (P_)((StgMutArrPtrs *)p)->payload; p < next; p++) { - (StgClosure *)*p = evacuate((StgClosure *)*p); + *p = (StgWord)(StgPtr)evacuate((StgClosure *)*p); } break; } @@ -2529,7 +3033,7 @@ linear_scan: evac_gen = 0; scavengeTSO(tso); evac_gen = saved_evac_gen; - failed_to_evac = rtsFalse; + failed_to_evac = rtsTrue; break; } @@ -2542,12 +3046,11 @@ linear_scan: StgInfoTable *rip = get_closure_info(p, &size, &ptrs, &nonptrs, &vhs, str); #endif StgRBH *rbh = (StgRBH *)p; - (StgClosure *)rbh->blocking_queue = - evacuate((StgClosure *)rbh->blocking_queue); - recordMutable((StgMutClosure *)rbh); - failed_to_evac = rtsFalse; // mutable anyhow. + bh->blocking_queue = + (StgTSO *)evacuate((StgClosure *)bh->blocking_queue); + failed_to_evac = rtsTrue; // mutable anyhow. IF_DEBUG(gc, - belch("@@ scavenge: RBH %p (%s) (new blocking_queue link=%p)", + debugBelch("@@ scavenge: RBH %p (%s) (new blocking_queue link=%p)", p, info_type(p), (StgClosure *)rbh->blocking_queue)); break; } @@ -2561,12 +3064,8 @@ linear_scan: // 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", + debugBelch("@@ scavenge: %p (%s); node is now %p; exciting, isn't it", bf, info_type((StgClosure *)bf), bf->node, info_type(bf->node))); break; @@ -2583,17 +3082,64 @@ linear_scan: 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", + debugBelch("@@ scavenge: %p (%s) exciting, isn't it", p, info_type((StgClosure *)p))); break; } #endif // PAR + case TVAR_WAIT_QUEUE: + { + StgTVarWaitQueue *wq = ((StgTVarWaitQueue *) p); + evac_gen = 0; + wq->waiting_tso = (StgTSO *)evacuate((StgClosure*)wq->waiting_tso); + wq->next_queue_entry = (StgTVarWaitQueue *)evacuate((StgClosure*)wq->next_queue_entry); + wq->prev_queue_entry = (StgTVarWaitQueue *)evacuate((StgClosure*)wq->prev_queue_entry); + evac_gen = saved_evac_gen; + failed_to_evac = rtsTrue; // mutable + break; + } + + case TVAR: + { + StgTVar *tvar = ((StgTVar *) p); + evac_gen = 0; + tvar->current_value = evacuate((StgClosure*)tvar->current_value); + tvar->first_wait_queue_entry = (StgTVarWaitQueue *)evacuate((StgClosure*)tvar->first_wait_queue_entry); + evac_gen = saved_evac_gen; + failed_to_evac = rtsTrue; // mutable + break; + } + + case TREC_CHUNK: + { + StgWord i; + StgTRecChunk *tc = ((StgTRecChunk *) p); + TRecEntry *e = &(tc -> entries[0]); + evac_gen = 0; + tc->prev_chunk = (StgTRecChunk *)evacuate((StgClosure*)tc->prev_chunk); + for (i = 0; i < tc -> next_entry_idx; i ++, e++ ) { + e->tvar = (StgTVar *)evacuate((StgClosure*)e->tvar); + e->expected_value = evacuate((StgClosure*)e->expected_value); + e->new_value = evacuate((StgClosure*)e->new_value); + } + evac_gen = saved_evac_gen; + failed_to_evac = rtsTrue; // mutable + break; + } + + case TREC_HEADER: + { + StgTRecHeader *trec = ((StgTRecHeader *) p); + evac_gen = 0; + trec->enclosing_trec = (StgTRecHeader *)evacuate((StgClosure*)trec->enclosing_trec); + trec->current_chunk = (StgTRecChunk *)evacuate((StgClosure*)trec->current_chunk); + evac_gen = saved_evac_gen; + failed_to_evac = rtsTrue; // mutable + break; + } + default: barf("scavenge_mark_stack: unimplemented/strange closure type %d @ %p", info->type, p); @@ -2601,7 +3147,7 @@ linear_scan: if (failed_to_evac) { failed_to_evac = rtsFalse; - mkMutCons((StgClosure *)q, &generations[evac_gen]); + recordMutableGen((StgClosure *)q, &generations[evac_gen]); } // mark the next bit to indicate "scavenged" @@ -2611,7 +3157,7 @@ linear_scan: // start a new linear scan if the mark stack overflowed at some point if (mark_stack_overflowed && oldgen_scan_bd == NULL) { - IF_DEBUG(gc, belch("scavenge_mark_stack: starting linear scan")); + IF_DEBUG(gc, debugBelch("scavenge_mark_stack: starting linear scan")); mark_stack_overflowed = rtsFalse; oldgen_scan_bd = oldest_gen->steps[0].blocks; oldgen_scan = oldgen_scan_bd->start; @@ -2663,13 +3209,23 @@ scavenge_one(StgPtr p) nat saved_evac_gen = evac_gen; rtsBool no_luck; - ASSERT(p && (LOOKS_LIKE_GHC_INFO(GET_INFO((StgClosure *)p)) - || IS_HUGS_CONSTR_INFO(GET_INFO((StgClosure *)p)))); - + ASSERT(LOOKS_LIKE_CLOSURE_PTR(p)); info = get_itbl((StgClosure *)p); switch (info->type) { + case MVAR: + { + StgMVar *mvar = ((StgMVar *)p); + evac_gen = 0; + mvar->head = (StgTSO *)evacuate((StgClosure *)mvar->head); + mvar->tail = (StgTSO *)evacuate((StgClosure *)mvar->tail); + mvar->value = evacuate((StgClosure *)mvar->value); + evac_gen = saved_evac_gen; + failed_to_evac = rtsTrue; // mutable. + break; + } + case FUN: case FUN_1_0: // hardly worth specialising these guys case FUN_0_1: @@ -2691,23 +3247,39 @@ scavenge_one(StgPtr p) case WEAK: case FOREIGN: case IND_PERM: - case IND_OLDGEN_PERM: { StgPtr q, end; end = (StgPtr)((StgClosure *)p)->payload + info->layout.payload.ptrs; for (q = (StgPtr)((StgClosure *)p)->payload; q < end; q++) { - (StgClosure *)*q = evacuate((StgClosure *)*q); + *q = (StgWord)(StgPtr)evacuate((StgClosure *)*q); } break; } + case MUT_VAR: + evac_gen = 0; + ((StgMutVar *)p)->var = evacuate(((StgMutVar *)p)->var); + evac_gen = saved_evac_gen; + failed_to_evac = rtsTrue; // mutable anyhow + break; + case CAF_BLACKHOLE: case SE_CAF_BLACKHOLE: case SE_BLACKHOLE: case BLACKHOLE: break; + case BLACKHOLE_BQ: + { + StgBlockingQueue *bh = (StgBlockingQueue *)p; + evac_gen = 0; // repeatedly mutable + bh->blocking_queue = + (StgTSO *)evacuate((StgClosure *)bh->blocking_queue); + failed_to_evac = rtsTrue; + break; + } + case THUNK_SELECTOR: { StgSelector *s = (StgSelector *)p; @@ -2715,34 +3287,49 @@ scavenge_one(StgPtr p) break; } + case AP_STACK: + { + StgAP_STACK *ap = (StgAP_STACK *)p; + + ap->fun = evacuate(ap->fun); + scavenge_stack((StgPtr)ap->payload, (StgPtr)ap->payload + ap->size); + p = (StgPtr)ap->payload + ap->size; + break; + } + + case PAP: + case AP: + p = scavenge_PAP((StgPAP *)p); + break; + case ARR_WORDS: // nothing to follow break; - + case MUT_ARR_PTRS: { // follow everything StgPtr next; evac_gen = 0; // repeatedly mutable - recordMutable((StgMutClosure *)p); next = p + mut_arr_ptrs_sizeW((StgMutArrPtrs*)p); for (p = (P_)((StgMutArrPtrs *)p)->payload; p < next; p++) { - (StgClosure *)*p = evacuate((StgClosure *)*p); + *p = (StgWord)(StgPtr)evacuate((StgClosure *)*p); } evac_gen = saved_evac_gen; - failed_to_evac = rtsFalse; + failed_to_evac = rtsTrue; break; } case MUT_ARR_PTRS_FROZEN: + case MUT_ARR_PTRS_FROZEN0: { // follow everything StgPtr next; next = p + mut_arr_ptrs_sizeW((StgMutArrPtrs*)p); for (p = (P_)((StgMutArrPtrs *)p)->payload; p < next; p++) { - (StgClosure *)*p = evacuate((StgClosure *)*p); + *p = (StgWord)(StgPtr)evacuate((StgClosure *)*p); } break; } @@ -2753,79 +3340,122 @@ scavenge_one(StgPtr p) evac_gen = 0; // repeatedly mutable scavengeTSO(tso); - recordMutable((StgMutClosure *)tso); evac_gen = saved_evac_gen; - failed_to_evac = rtsFalse; + failed_to_evac = rtsTrue; break; } - case AP_UPD: - case PAP: +#if defined(PAR) + case RBH: // cf. BLACKHOLE_BQ { - StgPAP* pap = (StgPAP *)p; - pap->fun = evacuate(pap->fun); - scavenge_stack((P_)pap->payload, (P_)pap->payload + pap->n_args); +#if 0 + nat size, ptrs, nonptrs, vhs; + char str[80]; + StgInfoTable *rip = get_closure_info(p, &size, &ptrs, &nonptrs, &vhs, str); +#endif + StgRBH *rbh = (StgRBH *)p; + (StgClosure *)rbh->blocking_queue = + evacuate((StgClosure *)rbh->blocking_queue); + failed_to_evac = rtsTrue; // mutable anyhow. + IF_DEBUG(gc, + debugBelch("@@ scavenge: RBH %p (%s) (new blocking_queue link=%p)", + p, info_type(p), (StgClosure *)rbh->blocking_queue)); + // ToDo: use size of reverted closure here! break; } - case IND_OLDGEN: - // This might happen if for instance a MUT_CONS was pointing to a - // THUNK which has since been updated. The IND_OLDGEN will - // be on the mutable list anyway, so we don't need to do anything - // here. + 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_DEBUG(gc, + debugBelch("@@ scavenge: %p (%s); node is now %p; exciting, isn't it", + bf, info_type((StgClosure *)bf), + bf->node, info_type(bf->node))); break; + } - default: - barf("scavenge_one: strange object %d", (int)(info->type)); - } - - no_luck = failed_to_evac; - failed_to_evac = rtsFalse; - return (no_luck); -} - -/* ----------------------------------------------------------------------------- - Scavenging mutable lists. +#ifdef DIST + case REMOTE_REF: +#endif + case FETCH_ME: + break; // nothing to do in this case - We treat the mutable list of each generation > N (i.e. all the - generations older than the one being collected) as roots. We also - remove non-mutable objects from the mutable list at this point. - -------------------------------------------------------------------------- */ + case FETCH_ME_BQ: // cf. BLACKHOLE_BQ + { + StgFetchMeBlockingQueue *fmbq = (StgFetchMeBlockingQueue *)p; + (StgClosure *)fmbq->blocking_queue = + evacuate((StgClosure *)fmbq->blocking_queue); + IF_DEBUG(gc, + debugBelch("@@ scavenge: %p (%s) exciting, isn't it", + p, info_type((StgClosure *)p))); + break; + } +#endif -static void -scavenge_mut_once_list(generation *gen) -{ - const StgInfoTable *info; - StgMutClosure *p, *next, *new_list; + case TVAR_WAIT_QUEUE: + { + StgTVarWaitQueue *wq = ((StgTVarWaitQueue *) p); + evac_gen = 0; + wq->waiting_tso = (StgTSO *)evacuate((StgClosure*)wq->waiting_tso); + wq->next_queue_entry = (StgTVarWaitQueue *)evacuate((StgClosure*)wq->next_queue_entry); + wq->prev_queue_entry = (StgTVarWaitQueue *)evacuate((StgClosure*)wq->prev_queue_entry); + evac_gen = saved_evac_gen; + failed_to_evac = rtsTrue; // mutable + break; + } - p = gen->mut_once_list; - new_list = END_MUT_LIST; - next = p->mut_link; + case TVAR: + { + StgTVar *tvar = ((StgTVar *) p); + evac_gen = 0; + tvar->current_value = evacuate((StgClosure*)tvar->current_value); + tvar->first_wait_queue_entry = (StgTVarWaitQueue *)evacuate((StgClosure*)tvar->first_wait_queue_entry); + evac_gen = saved_evac_gen; + failed_to_evac = rtsTrue; // mutable + break; + } - evac_gen = gen->no; - failed_to_evac = rtsFalse; + case TREC_HEADER: + { + StgTRecHeader *trec = ((StgTRecHeader *) p); + evac_gen = 0; + trec->enclosing_trec = (StgTRecHeader *)evacuate((StgClosure*)trec->enclosing_trec); + trec->current_chunk = (StgTRecChunk *)evacuate((StgClosure*)trec->current_chunk); + evac_gen = saved_evac_gen; + failed_to_evac = rtsTrue; // mutable + break; + } - for (; p != END_MUT_LIST; p = next, next = p->mut_link) { + case TREC_CHUNK: + { + StgWord i; + StgTRecChunk *tc = ((StgTRecChunk *) p); + TRecEntry *e = &(tc -> entries[0]); + evac_gen = 0; + tc->prev_chunk = (StgTRecChunk *)evacuate((StgClosure*)tc->prev_chunk); + for (i = 0; i < tc -> next_entry_idx; i ++, e++ ) { + e->tvar = (StgTVar *)evacuate((StgClosure*)e->tvar); + e->expected_value = evacuate((StgClosure*)e->expected_value); + e->new_value = evacuate((StgClosure*)e->new_value); + } + evac_gen = saved_evac_gen; + failed_to_evac = rtsTrue; // mutable + break; + } - // 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)))); - - 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: case IND_OLDGEN_PERM: case IND_STATIC: /* Try to pull the indirectee into this generation, so we can * remove the indirection from the mutable list. */ - ((StgIndOldGen *)p)->indirectee = - evacuate(((StgIndOldGen *)p)->indirectee); + ((StgInd *)p)->indirectee = evacuate(((StgInd *)p)->indirectee); #if 0 && defined(DEBUG) if (RtsFlags.DebugFlags.gc) @@ -2849,240 +3479,53 @@ scavenge_mut_once_list(generation *gen) } else { size = gen->steps[0].scan - start; } - belch("evac IND_OLDGEN: %ld bytes", size * sizeof(W_)); + debugBelch("evac IND_OLDGEN: %ld bytes", size * sizeof(W_)); } #endif - - /* failed_to_evac might happen if we've got more than two - * generations, we're collecting only generation 0, the - * indirection resides in generation 2 and the indirectee is - * in generation 1. - */ - if (failed_to_evac) { - failed_to_evac = rtsFalse; - p->mut_link = new_list; - new_list = p; - } else { - /* the mut_link field of an IND_STATIC is overloaded as the - * static link field too (it just so happens that we don't need - * both at the same time), so we need to NULL it out when - * removing this object from the mutable list because the static - * link fields are all assumed to be NULL before doing a major - * collection. - */ - p->mut_link = NULL; - } - continue; - - case MUT_CONS: - /* MUT_CONS is a kind of MUT_VAR, except it that we try to remove - * it from the mutable list if possible by promoting whatever it - * points to. - */ - if (scavenge_one((StgPtr)((StgMutVar *)p)->var)) { - /* didn't manage to promote everything, so put the - * MUT_CONS back on the list. - */ - p->mut_link = new_list; - new_list = p; - } - continue; + break; default: - // shouldn't have anything else on the mutables list - barf("scavenge_mut_once_list: strange object? %d", (int)(info->type)); - } - } + barf("scavenge_one: strange object %d", (int)(info->type)); + } - gen->mut_once_list = new_list; + no_luck = failed_to_evac; + failed_to_evac = rtsFalse; + return (no_luck); } +/* ----------------------------------------------------------------------------- + Scavenging mutable lists. + + We treat the mutable list of each generation > N (i.e. all the + generations older than the one being collected) as roots. We also + remove non-mutable objects from the mutable list at this point. + -------------------------------------------------------------------------- */ static void scavenge_mutable_list(generation *gen) { - const StgInfoTable *info; - StgMutClosure *p, *next; + bdescr *bd; + StgPtr p, q; - p = gen->saved_mut_list; - next = p->mut_link; + bd = gen->saved_mut_list; + + evac_gen = gen->no; + for (; bd != NULL; bd = bd->link) { + for (q = bd->start; q < bd->free; q++) { + p = (StgPtr)*q; + ASSERT(LOOKS_LIKE_CLOSURE_PTR(p)); + if (scavenge_one(p)) { + /* didn't manage to promote everything, so put the + * object back on the list. + */ + recordMutableGen((StgClosure *)p,gen); + } + } + } - evac_gen = 0; - failed_to_evac = rtsFalse; - - for (; p != END_MUT_LIST; p = next, next = p->mut_link) { - - // 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)))); - - 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: - // follow everything - p->mut_link = gen->mut_list; - gen->mut_list = p; - { - StgPtr end, q; - - end = (P_)p + mut_arr_ptrs_sizeW((StgMutArrPtrs*)p); - for (q = (P_)((StgMutArrPtrs *)p)->payload; q < end; q++) { - (StgClosure *)*q = evacuate((StgClosure *)*q); - } - continue; - } - - // Happens if a MUT_ARR_PTRS in the old generation is frozen - case MUT_ARR_PTRS_FROZEN: - { - StgPtr end, q; - - evac_gen = gen->no; - end = (P_)p + mut_arr_ptrs_sizeW((StgMutArrPtrs*)p); - for (q = (P_)((StgMutArrPtrs *)p)->payload; q < end; q++) { - (StgClosure *)*q = evacuate((StgClosure *)*q); - } - evac_gen = 0; - p->mut_link = NULL; - if (failed_to_evac) { - failed_to_evac = rtsFalse; - mkMutCons((StgClosure *)p, gen); - } - continue; - } - - case MUT_VAR: - ((StgMutVar *)p)->var = evacuate(((StgMutVar *)p)->var); - p->mut_link = gen->mut_list; - gen->mut_list = p; - continue; - - case MVAR: - { - StgMVar *mvar = (StgMVar *)p; - (StgClosure *)mvar->head = evacuate((StgClosure *)mvar->head); - (StgClosure *)mvar->tail = evacuate((StgClosure *)mvar->tail); - (StgClosure *)mvar->value = evacuate((StgClosure *)mvar->value); - p->mut_link = gen->mut_list; - gen->mut_list = p; - continue; - } - - case TSO: - { - StgTSO *tso = (StgTSO *)p; - - 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 - * above). - */ - tso->mut_link = gen->mut_list; - gen->mut_list = (StgMutClosure *)tso; - continue; - } - - case BLACKHOLE_BQ: - { - StgBlockingQueue *bh = (StgBlockingQueue *)p; - (StgClosure *)bh->blocking_queue = - evacuate((StgClosure *)bh->blocking_queue); - p->mut_link = gen->mut_list; - gen->mut_list = p; - 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_mutable_list: strange object? %d", (int)(info->type)); - } - } + // free the old mut_list + freeChain(gen->saved_mut_list); + gen->saved_mut_list = NULL; } @@ -3100,14 +3543,13 @@ scavenge_static(void) list... */ while (p != END_OF_STATIC_LIST) { + ASSERT(LOOKS_LIKE_CLOSURE_PTR(p)); 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)))); /* Take this object *off* the static_objects list, * and put it on the scavenged_static_objects list. @@ -3124,22 +3566,23 @@ scavenge_static(void) ind->indirectee = evacuate(ind->indirectee); /* might fail to evacuate it, in which case we have to pop it - * back on the mutable list (and take it off the - * scavenged_static list because the static link and mut link - * pointers are one and the same). + * back on the mutable list of the oldest generation. We + * leave it *on* the scavenged_static_objects list, though, + * in case we visit this object again. */ if (failed_to_evac) { failed_to_evac = rtsFalse; - scavenged_static_objects = IND_STATIC_LINK(p); - ((StgMutClosure *)ind)->mut_link = oldest_gen->mut_once_list; - oldest_gen->mut_once_list = (StgMutClosure *)ind; + recordMutableGen((StgClosure *)p,oldest_gen); } break; } case THUNK_STATIC: + scavenge_thunk_srt(info); + break; + case FUN_STATIC: - scavenge_srt(info); + scavenge_fun_srt(info); break; case CONSTR_STATIC: @@ -3149,7 +3592,7 @@ scavenge_static(void) next = (P_)p->payload + info->layout.payload.ptrs; // evacuate the pointers for (q = (P_)p->payload; q < next; q++) { - (StgClosure *)*q = evacuate((StgClosure *)*q); + *q = (StgWord)(StgPtr)evacuate((StgClosure *)*q); } break; } @@ -3169,200 +3612,166 @@ scavenge_static(void) } /* ----------------------------------------------------------------------------- + scavenge a chunk of memory described by a bitmap + -------------------------------------------------------------------------- */ + +static void +scavenge_large_bitmap( StgPtr p, StgLargeBitmap *large_bitmap, nat size ) +{ + nat i, b; + StgWord bitmap; + + b = 0; + bitmap = large_bitmap->bitmap[b]; + for (i = 0; i < size; ) { + if ((bitmap & 1) == 0) { + *p = (StgWord)(StgPtr)evacuate((StgClosure *)*p); + } + i++; + p++; + if (i % BITS_IN(W_) == 0) { + b++; + bitmap = large_bitmap->bitmap[b]; + } else { + bitmap = bitmap >> 1; + } + } +} + +STATIC_INLINE StgPtr +scavenge_small_bitmap (StgPtr p, nat size, StgWord bitmap) +{ + while (size > 0) { + if ((bitmap & 1) == 0) { + *p = (StgWord)(StgPtr)evacuate((StgClosure *)*p); + } + p++; + bitmap = bitmap >> 1; + size--; + } + return p; +} + +/* ----------------------------------------------------------------------------- scavenge_stack walks over a section of stack and evacuates all the objects pointed to by it. We can use the same code for walking - PAPs, since these are just sections of copied stack. + AP_STACK_UPDs, since these are just sections of copied stack. -------------------------------------------------------------------------- */ + static void scavenge_stack(StgPtr p, StgPtr stack_end) { - StgPtr q; - const StgInfoTable* info; + const StgRetInfoTable* info; StgWord bitmap; + nat size; - //IF_DEBUG(sanity, belch(" scavenging stack between %p and %p", p, stack_end)); + //IF_DEBUG(sanity, debugBelch(" scavenging stack between %p and %p", p, stack_end)); /* * Each time around this loop, we are looking at a chunk of stack - * that starts with either a pending argument section or an - * activation record. + * that starts with an activation record. */ while (p < stack_end) { - q = *(P_ *)p; - - // If we've got a tag, skip over that many words on the stack - 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) ) { -#ifdef DEBUG - 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); - p++; - continue; - } - - /* - * Otherwise, q must be the info pointer of an activation - * record. All activation records have 'bitmap' style layout - * info. - */ - info = get_itbl((StgClosure *)p); + info = get_ret_itbl((StgClosure *)p); - switch (info->type) { + switch (info->i.type) { - // Dynamic bitmap: the mask is stored on the stack - case RET_DYN: - 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: - { -#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, - * or BLACKHOLE_BQ, so just inline the code to evacuate it here. - */ case UPDATE_FRAME: - { - StgUpdateFrame *frame = (StgUpdateFrame *)p; - + ((StgUpdateFrame *)p)->updatee + = evacuate(((StgUpdateFrame *)p)->updatee); p += sizeofW(StgUpdateFrame); - -#ifndef not_yet - frame->updatee = evacuate(frame->updatee); continue; -#else // specialised code for update frames, not sure if it's worth it. - StgClosure *to; - nat type = get_itbl(frame->updatee)->type; - - if (type == EVACUATED) { - frame->updatee = evacuate(frame->updatee); - continue; - } else { - bdescr *bd = Bdescr((P_)frame->updatee); - step *stp; - if (bd->gen_no > N) { - if (bd->gen_no < evac_gen) { - failed_to_evac = rtsTrue; - } - continue; - } - - // 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), stp); - frame->updatee = to; - continue; - case BLACKHOLE_BQ: - 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"); - } - } -#endif - } // small bitmap (< 32 entries, or 64 on a 64-bit machine) + case CATCH_STM_FRAME: + case CATCH_RETRY_FRAME: + case ATOMICALLY_FRAME: 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) { - (StgClosure *)*p = evacuate((StgClosure *)*p); - } + bitmap = BITMAP_BITS(info->i.layout.bitmap); + size = BITMAP_SIZE(info->i.layout.bitmap); + // NOTE: the payload starts immediately after the info-ptr, we + // don't have an StgHeader in the same sense as a heap closure. p++; - bitmap = bitmap >> 1; - } - + p = scavenge_small_bitmap(p, size, bitmap); + follow_srt: - scavenge_srt(info); - continue; + scavenge_srt((StgClosure **)GET_SRT(info), info->i.srt_bitmap); + continue; + + case RET_BCO: { + StgBCO *bco; + nat size; + + p++; + *p = (StgWord)(StgPtr)evacuate((StgClosure *)*p); + bco = (StgBCO *)*p; + p++; + size = BCO_BITMAP_SIZE(bco); + scavenge_large_bitmap(p, BCO_BITMAP(bco), size); + p += size; + continue; + } // large bitmap (> 32 entries, or > 64 on a 64-bit machine) case RET_BIG: case RET_VEC_BIG: - { - StgPtr q; - StgLargeBitmap *large_bitmap; - nat i; + { + nat size; - large_bitmap = info->layout.large_bitmap; + size = GET_LARGE_BITMAP(&info->i)->size; p++; + scavenge_large_bitmap(p, GET_LARGE_BITMAP(&info->i), size); + p += size; + // and don't forget to follow the SRT + goto follow_srt; + } - for (i=0; isize; i++) { - bitmap = large_bitmap->bitmap[i]; - q = p + BITS_IN(W_); - while (bitmap != 0) { - if ((bitmap & 1) == 0) { - (StgClosure *)*p = evacuate((StgClosure *)*p); - } + // Dynamic bitmap: the mask is stored on the stack, and + // there are a number of non-pointers followed by a number + // of pointers above the bitmapped area. (see StgMacros.h, + // HEAP_CHK_GEN). + case RET_DYN: + { + StgWord dyn; + dyn = ((StgRetDyn *)p)->liveness; + + // traverse the bitmap first + bitmap = RET_DYN_LIVENESS(dyn); + p = (P_)&((StgRetDyn *)p)->payload[0]; + size = RET_DYN_BITMAP_SIZE; + p = scavenge_small_bitmap(p, size, bitmap); + + // skip over the non-ptr words + p += RET_DYN_NONPTRS(dyn) + RET_DYN_NONPTR_REGS_SIZE; + + // follow the ptr words + for (size = RET_DYN_PTRS(dyn); size > 0; size--) { + *p = (StgWord)(StgPtr)evacuate((StgClosure *)*p); p++; - bitmap = bitmap >> 1; - } - if (i+1 < large_bitmap->size) { - while (p < q) { - (StgClosure *)*p = evacuate((StgClosure *)*p); - p++; - } - } } + continue; + } - // and don't forget to follow the SRT + case RET_FUN: + { + StgRetFun *ret_fun = (StgRetFun *)p; + StgFunInfoTable *fun_info; + + ret_fun->fun = evacuate(ret_fun->fun); + fun_info = get_fun_itbl(ret_fun->fun); + p = scavenge_arg_block(fun_info, ret_fun->payload); goto follow_srt; - } + } default: - barf("scavenge_stack: weird activation record found on stack: %d", (int)(info->type)); + barf("scavenge_stack: weird activation record found on stack: %d", (int)(info->i.type)); } - } + } } /*----------------------------------------------------------------------------- @@ -3397,7 +3806,7 @@ scavenge_large(step *stp) p = bd->start; if (scavenge_one(p)) { - mkMutCons((StgClosure *)p, stp->gen); + recordMutableGen((StgClosure *)p, stp->gen); } } } @@ -3420,26 +3829,6 @@ zero_static_object_list(StgClosure* first_static) } } -/* This function is only needed because we share the mutable link - * field with the static link field in an IND_STATIC, so we have to - * zero the mut_link field before doing a major GC, which needs the - * static link field. - * - * It doesn't do any harm to zero all the mutable link fields on the - * mutable list. - */ - -static void -zero_mutable_list( StgMutClosure *first ) -{ - StgMutClosure *next, *c; - - for (c = first; c != END_MUT_LIST; c = next) { - next = c->mut_link; - c->mut_link = NULL; - } -} - /* ----------------------------------------------------------------------------- Reverting CAFs -------------------------------------------------------------------------- */ @@ -3452,7 +3841,7 @@ revertCAFs( void ) for (c = (StgIndStatic *)caf_list; c != NULL; c = (StgIndStatic *)c->static_link) { - c->header.info = c->saved_info; + SET_INFO(c, c->saved_info); c->saved_info = NULL; // could, but not necessary: c->static_link = NULL; } @@ -3460,15 +3849,14 @@ revertCAFs( void ) } void -scavengeCAFs( void ) +markCAFs( evac_fn evac ) { StgIndStatic *c; - evac_gen = 0; for (c = (StgIndStatic *)caf_list; c != NULL; c = (StgIndStatic *)c->static_link) { - c->indirectee = evacuate(c->indirectee); + evac(&c->indirectee); } } @@ -3505,7 +3893,7 @@ gcCAFs(void) ASSERT(info->type == IND_STATIC); if (STATIC_LINK(info,p) == NULL) { - IF_DEBUG(gccafs, belch("CAF gc'd at 0x%04lx", (long)p)); + IF_DEBUG(gccafs, debugBelch("CAF gc'd at 0x%04lx", (long)p)); // black hole it SET_INFO(p,&stg_BLACKHOLE_info); p = STATIC_LINK2(info,p); @@ -3519,7 +3907,7 @@ gcCAFs(void) } - // belch("%d CAFs live", i); + // debugBelch("%d CAFs live", i); } #endif @@ -3535,55 +3923,61 @@ gcCAFs(void) static void threadLazyBlackHole(StgTSO *tso) { - StgUpdateFrame *update_frame; - StgBlockingQueue *bh; - StgPtr stack_end; - - stack_end = &tso->stack[tso->stack_size]; - update_frame = tso->su; - - while (1) { - switch (get_itbl(update_frame)->type) { - - case CATCH_FRAME: - update_frame = ((StgCatchFrame *)update_frame)->link; - break; - - case UPDATE_FRAME: - bh = (StgBlockingQueue *)update_frame->updatee; - - /* if the thunk is already blackholed, it means we've also - * already blackholed the rest of the thunks on this stack, - * so we can stop early. - * - * The blackhole made for a CAF is a CAF_BLACKHOLE, so they - * don't interfere with this optimisation. - */ - if (bh->header.info == &stg_BLACKHOLE_info) { - return; - } + StgClosure *frame; + StgRetInfoTable *info; + StgBlockingQueue *bh; + StgPtr stack_end; + + stack_end = &tso->stack[tso->stack_size]; + + frame = (StgClosure *)tso->sp; - if (bh->header.info != &stg_BLACKHOLE_BQ_info && - bh->header.info != &stg_CAF_BLACKHOLE_info) { + while (1) { + info = get_ret_itbl(frame); + + switch (info->i.type) { + + case UPDATE_FRAME: + bh = (StgBlockingQueue *)((StgUpdateFrame *)frame)->updatee; + + /* if the thunk is already blackholed, it means we've also + * already blackholed the rest of the thunks on this stack, + * so we can stop early. + * + * The blackhole made for a CAF is a CAF_BLACKHOLE, so they + * don't interfere with this optimisation. + */ + if (bh->header.info == &stg_BLACKHOLE_info) { + return; + } + + if (bh->header.info != &stg_BLACKHOLE_BQ_info && + bh->header.info != &stg_CAF_BLACKHOLE_info) { #if (!defined(LAZY_BLACKHOLING)) && defined(DEBUG) - belch("Unexpected lazy BHing required at 0x%04x",(int)bh); + debugBelch("Unexpected lazy BHing required at 0x%04x",(int)bh); #endif - SET_INFO(bh,&stg_BLACKHOLE_info); - } - - update_frame = update_frame->link; - break; - - case SEQ_FRAME: - update_frame = ((StgSeqFrame *)update_frame)->link; - break; +#ifdef PROFILING + // @LDV profiling + // We pretend that bh is now dead. + LDV_recordDead_FILL_SLOP_DYNAMIC((StgClosure *)bh); +#endif + SET_INFO(bh,&stg_BLACKHOLE_info); - case STOP_FRAME: - return; - default: - barf("threadPaused"); + // We pretend that bh has just been created. + LDV_RECORD_CREATE(bh); + } + + frame = (StgClosure *) ((StgUpdateFrame *)frame + 1); + break; + + case STOP_FRAME: + return; + + // normal stack frames; do nothing except advance the pointer + default: + frame = (StgClosure *)((StgPtr)frame + stack_frame_sizeW(frame)); + } } - } } @@ -3595,264 +3989,203 @@ threadLazyBlackHole(StgTSO *tso) * * -------------------------------------------------------------------------- */ +struct stack_gap { StgWord gap_size; struct stack_gap *next_gap; }; + static void threadSqueezeStack(StgTSO *tso) { - lnat displacement = 0; - StgUpdateFrame *frame; - StgUpdateFrame *next_frame; // Temporally next - 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 + StgPtr frame; + rtsBool prev_was_update_frame; + StgClosure *updatee = NULL; + StgPtr bottom; + StgRetInfoTable *info; + StgWord current_gap_size; + struct stack_gap *gap; - top_frame = tso->su; -#endif - - bottom = &(tso->stack[tso->stack_size]); - frame = tso->su; + // Stage 1: + // Traverse the stack upwards, replacing adjacent update frames + // with a single update frame and a "stack gap". A stack gap + // contains two values: the size of the gap, and the distance + // to the next gap (or the stack top). - /* There must be at least one frame, namely the STOP_FRAME. - */ - ASSERT((P_)frame < bottom); + bottom = &(tso->stack[tso->stack_size]); - /* Walk down the stack, reversing the links between frames so that - * we can walk back up as we squeeze from the bottom. Note that - * next_frame and prev_frame refer to next and previous as they were - * added to the stack, rather than the way we see them in this - * walk. (It makes the next loop less confusing.) - * - * Stop if we find an update frame pointing to a black hole - * (see comment in threadLazyBlackHole()). - */ - - next_frame = NULL; - // 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 == &stg_BLACKHOLE_info) { - break; - } - } + frame = tso->sp; - /* Now, we're at the bottom. Frame points to the lowest update - * frame on the stack, and its link actually points to the frame - * above. We have to walk back up the stack, squeezing out empty - * update frames and turning the pointers back around on the way - * back up. - * - * The bottom-most frame (the STOP_FRAME) has not been altered, and - * we never want to eliminate it anyway. Just walk one step up - * before starting to squeeze. When you get to the topmost frame, - * remember that there are still some words above it that might have - * to be moved. - */ - - prev_frame = frame; - frame = next_frame; + ASSERT(frame < bottom); + + prev_was_update_frame = rtsFalse; + current_gap_size = 0; + gap = (struct stack_gap *) (tso->sp - sizeofW(StgUpdateFrame)); - prev_was_update_frame = (get_itbl(prev_frame)->type == UPDATE_FRAME); + while (frame < bottom) { + + info = get_ret_itbl((StgClosure *)frame); + switch (info->i.type) { - /* - * Loop through all of the frames (everything except the very - * bottom). Things are complicated by the fact that we have - * CATCH_FRAMEs and SEQ_FRAMEs interspersed with the update frames. - * We can only squeeze when there are two consecutive UPDATE_FRAMEs. - */ - while (frame != NULL) { - StgPtr sp; - StgPtr frame_bottom = (P_)frame + sizeofW(StgUpdateFrame); - rtsBool is_update_frame; - - next_frame = frame->link; - is_update_frame = (get_itbl(frame)->type == UPDATE_FRAME); + case UPDATE_FRAME: + { + StgUpdateFrame *upd = (StgUpdateFrame *)frame; - /* Check to see if - * 1. both the previous and current frame are update frames - * 2. the current frame is empty - */ - if (prev_was_update_frame && is_update_frame && - (P_)prev_frame == frame_bottom + displacement) { - - // Now squeeze out the current frame - StgClosure *updatee_keep = prev_frame->updatee; - StgClosure *updatee_bypass = frame->updatee; - -#if DEBUG - IF_DEBUG(gc, belch("@@ squeezing frame at %p", frame)); - squeezes++; -#endif + if (upd->updatee->header.info == &stg_BLACKHOLE_info) { - /* Deal with blocking queues. If both updatees have blocked - * threads, then we should merge the queues into the update - * frame that we're keeping. - * - * Alternatively, we could just wake them up: they'll just go - * straight to sleep on the proper blackhole! This is less code - * and probably less bug prone, although it's probably much - * slower --SDM - */ -#if 0 // do it properly... -# 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) == stg_BLACKHOLE_BQ_info) { - // Urgh. Two queues. Merge them. - P_ keep_tso = ((StgBlockingQueue *)updatee_keep)->blocking_queue; - - while (keep_tso->link != END_TSO_QUEUE) { - keep_tso = keep_tso->link; - } - keep_tso->link = ((StgBlockingQueue *)updatee_bypass)->blocking_queue; + // found a BLACKHOLE'd update frame; we've been here + // before, in a previous GC, so just break out. - } else { - // For simplicity, just swap the BQ for the BH - P_ temp = updatee_keep; - - updatee_keep = updatee_bypass; - updatee_bypass = temp; - - // Record the swap in the kept frame (below) - prev_frame->updatee = updatee_keep; - } - } -#endif + // Mark the end of the gap, if we're in one. + if (current_gap_size != 0) { + gap = (struct stack_gap *)(frame-sizeofW(StgUpdateFrame)); + } + + frame += sizeofW(StgUpdateFrame); + goto done_traversing; + } - TICK_UPD_SQUEEZED(); - /* 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); - - } else { - // No squeeze for this frame - sp = frame_bottom - 1; // Keep the current frame - - /* Do lazy black-holing. - */ - if (is_update_frame) { - StgBlockingQueue *bh = (StgBlockingQueue *)frame->updatee; - if (bh->header.info != &stg_BLACKHOLE_info && - bh->header.info != &stg_BLACKHOLE_BQ_info && - bh->header.info != &stg_CAF_BLACKHOLE_info) { + if (prev_was_update_frame) { + + TICK_UPD_SQUEEZED(); + /* 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 (upd->updatee != updatee && !closure_IND(upd->updatee)) { + // this wakes the threads up + UPD_IND_NOLOCK(upd->updatee, updatee); + } + + // now mark this update frame as a stack gap. The gap + // marker resides in the bottom-most update frame of + // the series of adjacent frames, and covers all the + // frames in this series. + current_gap_size += sizeofW(StgUpdateFrame); + ((struct stack_gap *)frame)->gap_size = current_gap_size; + ((struct stack_gap *)frame)->next_gap = gap; + + frame += sizeofW(StgUpdateFrame); + continue; + } + + // single update frame, or the topmost update frame in a series + else { + StgBlockingQueue *bh = (StgBlockingQueue *)upd->updatee; + + // Do lazy black-holing + 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) - belch("Unexpected lazy BHing required at 0x%04x",(int)bh); + debugBelch("Unexpected lazy BHing required at 0x%04x",(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 its 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; - } - } - } + /* zero out the slop so that the sanity checker can tell + * where the next closure is. + */ + { + StgInfoTable *bh_info = get_itbl(bh); + nat np = bh_info->layout.payload.ptrs, + nw = bh_info->layout.payload.nptrs, i; + /* don't zero out slop for a THUNK_SELECTOR, + * because its layout info is used for a + * different purpose, and it's exactly the + * same size as a BLACKHOLE in any case. + */ + if (bh_info->type != THUNK_SELECTOR) { + for (i = 0; i < np + nw; i++) { + ((StgClosure *)bh)->payload[i] = INVALID_OBJECT; + } + } + } +#endif +#ifdef PROFILING + // We pretend that bh is now dead. + LDV_recordDead_FILL_SLOP_DYNAMIC((StgClosure *)bh); #endif - SET_INFO(bh,&stg_BLACKHOLE_info); + // Todo: maybe use SET_HDR() and remove LDV_RECORD_CREATE()? + SET_INFO(bh,&stg_BLACKHOLE_info); + + // We pretend that bh has just been created. + LDV_RECORD_CREATE(bh); + } + + prev_was_update_frame = rtsTrue; + updatee = upd->updatee; + frame += sizeofW(StgUpdateFrame); + continue; + } } - } + + default: + prev_was_update_frame = rtsFalse; - // Fix the link in the current frame (should point to the frame below) - frame->link = prev_frame; - prev_was_update_frame = is_update_frame; - } - - // Now slide all words from sp up to the next frame - - if (displacement > 0) { - P_ next_frame_bottom; + // we're not in a gap... check whether this is the end of a gap + // (an update frame can't be the end of a gap). + if (current_gap_size != 0) { + gap = (struct stack_gap *) (frame - sizeofW(StgUpdateFrame)); + } + current_gap_size = 0; - if (next_frame != NULL) - next_frame_bottom = (P_)next_frame + sizeofW(StgUpdateFrame); - else - next_frame_bottom = tso->sp - 1; - -#if 0 - IF_DEBUG(gc, - belch("sliding [%p, %p] by %ld", sp, next_frame_bottom, - displacement)) -#endif - - while (sp >= next_frame_bottom) { - sp[displacement] = *sp; - sp -= 1; - } + frame += stack_frame_sizeW((StgClosure *)frame); + continue; + } } - (P_)prev_frame = (P_)frame + displacement; - frame = next_frame; - } - tso->sp += displacement; - tso->su = prev_frame; -#if 0 - IF_DEBUG(gc, - belch("@@ threadSqueezeStack: squeezed %d update-frames; found %d BHs; found %d update-, %d stop-, %d catch, %d seq-frames", - squeezes, bhs, upd_frames, stop_frames, catch_frames, seq_frames)) -#endif -} +done_traversing: + + // Now we have a stack with gaps in it, and we have to walk down + // shoving the stack up to fill in the gaps. A diagram might + // help: + // + // +| ********* | + // | ********* | <- sp + // | | + // | | <- gap_start + // | ......... | | + // | stack_gap | <- gap | chunk_size + // | ......... | | + // | ......... | <- gap_end v + // | ********* | + // | ********* | + // | ********* | + // -| ********* | + // + // 'sp' points the the current top-of-stack + // 'gap' points to the stack_gap structure inside the gap + // ***** indicates real stack data + // ..... indicates gap + // indicates unused + // + { + void *sp; + void *gap_start, *next_gap_start, *gap_end; + nat chunk_size; + + next_gap_start = (void *)((unsigned char*)gap + sizeof(StgUpdateFrame)); + sp = next_gap_start; + + while ((StgPtr)gap > tso->sp) { + // we're working in *bytes* now... + gap_start = next_gap_start; + gap_end = (void*) ((unsigned char*)gap_start - gap->gap_size * sizeof(W_)); + + gap = gap->next_gap; + next_gap_start = (void *)((unsigned char*)gap + sizeof(StgUpdateFrame)); + + chunk_size = (unsigned char*)gap_end - (unsigned char*)next_gap_start; + sp -= chunk_size; + memmove(sp, next_gap_start, chunk_size); + } + + tso->sp = (StgPtr)sp; + } +} /* ----------------------------------------------------------------------------- * Pausing a thread @@ -3876,38 +4209,22 @@ threadPaused(StgTSO *tso) #if DEBUG 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); -} - -void printMutableList(generation *gen) { - StgMutClosure *p, *next; + bdescr *bd; + StgPtr p; - p = gen->mut_list; - next = p->mut_link; + debugBelch("@@ Mutable list %p: ", gen->mut_list); - 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); + for (bd = gen->mut_list; bd != NULL; bd = bd->link) { + for (p = bd->start; p < bd->free; p++) { + debugBelch("%p (%s), ", (void *)*p, info_type((StgClosure *)*p)); + } + } + debugBelch("\n"); } -static inline rtsBool +STATIC_INLINE rtsBool maybeLarge(StgClosure *closure) { StgInfoTable *info = get_itbl(closure); @@ -3916,6 +4233,7 @@ maybeLarge(StgClosure *closure) see scavenge_large */ return (info->type == MUT_ARR_PTRS || info->type == MUT_ARR_PTRS_FROZEN || + info->type == MUT_ARR_PTRS_FROZEN0 || info->type == TSO || info->type == ARR_WORDS); }