static void searchStackChunk (HashTable *addrs, StgPtr sp, StgPtr stack_end)
{
StgPtr p;
const StgRetInfoTable *info;
p = sp;
while (p < stack_end) {
info = get_ret_itbl((StgClosure *)p);
switch (info->i.type) {
case RET_SMALL:
case RET_BIG:
checkAddress(addrs, (void*)info);
break;
default:
break;
}
p += stack_frame_sizeW((StgClosure*)p);
}
}
void
printStackChunk( StgPtr sp, StgPtr spBottom )
{
StgWord bitmap;
const StgInfoTable *info;
ASSERT(sp <= spBottom);
for (; sp < spBottom; sp += stack_frame_sizeW((StgClosure *)sp)) {
info = get_itbl((StgClosure *)sp);
switch (info->type) {
case UPDATE_FRAME:
case CATCH_FRAME:
case UNDERFLOW_FRAME:
case STOP_FRAME:
printClosure((StgClosure*)sp);
continue;
case RET_SMALL: {
StgWord c = *sp;
if (c == (StgWord)&stg_ctoi_R1p_info) {
debugBelch("tstg_ctoi_ret_R1p_info\n" );
} else if (c == (StgWord)&stg_ctoi_R1n_info) {
debugBelch("stg_ctoi_ret_R1n_info\n" );
} else if (c == (StgWord)&stg_ctoi_F1_info) {
debugBelch("stg_ctoi_ret_F1_info\n" );
} else if (c == (StgWord)&stg_ctoi_D1_info) {
debugBelch("stg_ctoi_ret_D1_info\n" );
} else if (c == (StgWord)&stg_ctoi_V_info) {
debugBelch("stg_ctoi_ret_V_info\n" );
} else if (c == (StgWord)&stg_ap_v_info) {
debugBelch("stg_ap_v_info\n" );
} else if (c == (StgWord)&stg_ap_f_info) {
debugBelch("stg_ap_f_info\n" );
} else if (c == (StgWord)&stg_ap_d_info) {
debugBelch("stg_ap_d_info\n" );
} else if (c == (StgWord)&stg_ap_l_info) {
debugBelch("stg_ap_l_info\n" );
} else if (c == (StgWord)&stg_ap_n_info) {
debugBelch("stg_ap_n_info\n" );
} else if (c == (StgWord)&stg_ap_p_info) {
debugBelch("stg_ap_p_info\n" );
} else if (c == (StgWord)&stg_ap_pp_info) {
debugBelch("stg_ap_pp_info\n" );
} else if (c == (StgWord)&stg_ap_ppp_info) {
debugBelch("stg_ap_ppp_info\n" );
} else if (c == (StgWord)&stg_ap_pppp_info) {
debugBelch("stg_ap_pppp_info\n" );
} else if (c == (StgWord)&stg_ap_ppppp_info) {
debugBelch("stg_ap_ppppp_info\n" );
} else if (c == (StgWord)&stg_ap_pppppp_info) {
debugBelch("stg_ap_pppppp_info\n" );
#ifdef PROFILING
} else if (c == (StgWord)&stg_restore_cccs_info) {
debugBelch("stg_restore_cccs_info\n" );
fprintCCS(stderr, (CostCentreStack*)sp[1]);
debugBelch("\n" );
continue;
#endif
} else {
debugBelch("RET_SMALL (%p)\n", info);
}
bitmap = info->layout.bitmap;
printSmallBitmap(spBottom, sp+1,
BITMAP_BITS(bitmap), BITMAP_SIZE(bitmap));
continue;
}
case RET_BCO: {
StgBCO *bco;
bco = ((StgBCO *)sp[1]);
debugBelch("RET_BCO (%p)\n", sp);
printLargeBitmap(spBottom, sp+2,
BCO_BITMAP(bco), BCO_BITMAP_SIZE(bco));
continue;
}
case RET_BIG:
barf("todo");
case RET_FUN:
{
const StgFunInfoTable *fun_info;
StgRetFun *ret_fun;
ret_fun = (StgRetFun *)sp;
fun_info = get_fun_itbl(ret_fun->fun);
debugBelch("RET_FUN (%p) (type=%d)\n", ret_fun->fun, (int)fun_info->f.fun_type);
switch (fun_info->f.fun_type) {
case ARG_GEN:
printSmallBitmap(spBottom, sp+2,
BITMAP_BITS(fun_info->f.b.bitmap),
BITMAP_SIZE(fun_info->f.b.bitmap));
break;
case ARG_GEN_BIG:
printLargeBitmap(spBottom, sp+2,
GET_FUN_LARGE_BITMAP(fun_info),
GET_FUN_LARGE_BITMAP(fun_info)->size);
break;
default:
printSmallBitmap(spBottom, sp+2,
BITMAP_BITS(stg_arg_bitmaps[fun_info->f.fun_type]),
BITMAP_SIZE(stg_arg_bitmaps[fun_info->f.fun_type]));
break;
}
continue;
}
default:
debugBelch("unknown object %d\n", (int)info->type);
barf("printStackChunk");
}
}
}
static void
stackSqueeze(Capability *cap, StgTSO *tso, StgPtr bottom)
{
StgPtr frame;
uint32_t adjacent_update_frames;
struct stack_gap *gap;
// 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).
frame = tso->stackobj->sp;
ASSERT(frame < bottom);
adjacent_update_frames = 0;
gap = (struct stack_gap *) (frame - sizeofW(StgUpdateFrame));
while (frame <= bottom)
{
switch (get_ret_itbl((StgClosure *)frame)->i.type) {
case UPDATE_FRAME:
{
if (adjacent_update_frames > 0) {
TICK_UPD_SQUEEZED();
}
adjacent_update_frames++;
frame += sizeofW(StgUpdateFrame);
continue;
}
default:
// 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 (adjacent_update_frames > 1) {
gap = updateAdjacentFrames(cap, tso,
(StgUpdateFrame*)(frame - sizeofW(StgUpdateFrame)),
adjacent_update_frames, gap);
}
adjacent_update_frames = 0;
frame += stack_frame_sizeW((StgClosure *)frame);
continue;
}
}
if (adjacent_update_frames > 1) {
gap = updateAdjacentFrames(cap, tso,
(StgUpdateFrame*)(frame - sizeofW(StgUpdateFrame)),
adjacent_update_frames, gap);
}
// Now we have a stack with gap-structs 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
// <empty> indicates unused
//
{
StgWord8 *sp;
StgWord8 *gap_start, *next_gap_start, *gap_end;
uint32_t chunk_size;
next_gap_start = (StgWord8*)gap + sizeof(StgUpdateFrame);
sp = next_gap_start;
while ((StgPtr)gap > tso->stackobj->sp) {
// we're working in *bytes* now...
gap_start = next_gap_start;
gap_end = gap_start - gap->gap_size * sizeof(W_);
gap = gap->next_gap;
next_gap_start = (StgWord8*)gap + sizeof(StgUpdateFrame);
chunk_size = gap_end - next_gap_start;
sp -= chunk_size;
memmove(sp, next_gap_start, chunk_size);
}
tso->stackobj->sp = (StgPtr)sp;
}
}
/* -----------------------------------------------------------------------------
* Pausing a thread
*
* We have to prepare for GC - this means doing lazy black holing
* here. We also take the opportunity to do stack squeezing if it's
* turned on.
* -------------------------------------------------------------------------- */
void
threadPaused(Capability *cap, StgTSO *tso)
{
StgClosure *frame;
const StgRetInfoTable *info;
const StgInfoTable *bh_info;
const StgInfoTable *cur_bh_info USED_IF_THREADS;
StgClosure *bh;
StgPtr stack_end;
uint32_t words_to_squeeze = 0;
uint32_t weight = 0;
uint32_t weight_pending = 0;
bool prev_was_update_frame = false;
StgWord heuristic_says_squeeze;
// Check to see whether we have threads waiting to raise
// exceptions, and we're not blocking exceptions, or are blocked
// interruptibly. This is important; if a thread is running with
// TSO_BLOCKEX and becomes blocked interruptibly, this is the only
// place we ensure that the blocked_exceptions get a chance.
maybePerformBlockedException (cap, tso);
if (tso->what_next == ThreadKilled) { return; }
// NB. Updatable thunks *must* be blackholed, either by eager blackholing or
// lazy blackholing. See Note [upd-black-hole] in sm/Scav.c.
stack_end = tso->stackobj->stack + tso->stackobj->stack_size;
frame = (StgClosure *)tso->stackobj->sp;
while ((P_)frame < stack_end) {
info = get_ret_itbl(frame);
switch (info->i.type) {
case UPDATE_FRAME:
// If we've already marked this frame, then stop here.
if (frame->header.info == (StgInfoTable *)&stg_marked_upd_frame_info) {
if (prev_was_update_frame) {
words_to_squeeze += sizeofW(StgUpdateFrame);
weight += weight_pending;
weight_pending = 0;
}
goto end;
}
SET_INFO(frame, (StgInfoTable *)&stg_marked_upd_frame_info);
bh = ((StgUpdateFrame *)frame)->updatee;
bh_info = bh->header.info;
#if defined(THREADED_RTS)
retry:
#endif
// Note [suspend duplicate work]
//
// If the info table is a WHITEHOLE or a BLACKHOLE, then
// another thread has claimed it (via the SET_INFO()
// below), or is in the process of doing so. In that case
// we want to suspend the work that the current thread has
// done on this thunk and wait until the other thread has
// finished.
//
// If eager blackholing is taking place, it could be the
// case that the blackhole points to the current
// TSO. e.g.:
//
// this thread other thread
// --------------------------------------------------------
// c->indirectee = other_tso;
// c->header.info = EAGER_BH
// threadPaused():
// c->header.info = WHITEHOLE
// c->indirectee = other_tso
// c->indirectee = this_tso;
// c->header.info = EAGER_BH
// c->header.info = BLACKHOLE
// threadPaused()
// *** c->header.info is now BLACKHOLE,
// c->indirectee points to this_tso
//
// So in this case do *not* suspend the work of the
// current thread, because the current thread will become
// deadlocked on itself. See #5226 for an instance of
// this bug.
//
// Note that great care is required when entering computations
// suspended by this mechanism. See Note [AP_STACKs must be eagerly
// blackholed] for details.
if (((bh_info == &stg_BLACKHOLE_info)
&& ((StgInd*)bh)->indirectee != (StgClosure*)tso)
|| (bh_info == &stg_WHITEHOLE_info))
{
debugTrace(DEBUG_squeeze,
"suspending duplicate work: %ld words of stack",
(long)((StgPtr)frame - tso->stackobj->sp));
// If this closure is already an indirection, then
// suspend the computation up to this point.
// NB. check raiseAsync() to see what happens when
// we're in a loop (#2783).
suspendComputation(cap,tso,(StgUpdateFrame*)frame);
// Now drop the update frame, and arrange to return
// the value to the frame underneath:
tso->stackobj->sp = (StgPtr)frame + sizeofW(StgUpdateFrame) - 2;
tso->stackobj->sp[1] = (StgWord)bh;
ASSERT(bh->header.info != &stg_TSO_info);
tso->stackobj->sp[0] = (W_)&stg_enter_info;
// And continue with threadPaused; there might be
// yet more computation to suspend.
frame = (StgClosure *)(tso->stackobj->sp + 2);
prev_was_update_frame = false;
continue;
}
// We should never have made it here in the event of blackholes that
// we already own; they should have been marked when we blackholed
// them and consequently we should have stopped our stack walk
// above.
ASSERT(!((bh_info == &stg_BLACKHOLE_info)
&& (((StgInd*)bh)->indirectee == (StgClosure*)tso)));
// zero out the slop so that the sanity checker can tell
// where the next closure is.
OVERWRITING_CLOSURE(bh);
// an EAGER_BLACKHOLE or CAF_BLACKHOLE gets turned into a
// BLACKHOLE here.
#if defined(THREADED_RTS)
// first we turn it into a WHITEHOLE to claim it, and if
// successful we write our TSO and then the BLACKHOLE info pointer.
cur_bh_info = (const StgInfoTable *)
cas((StgVolatilePtr)&bh->header.info,
(StgWord)bh_info,
(StgWord)&stg_WHITEHOLE_info);
if (cur_bh_info != bh_info) {
bh_info = cur_bh_info;
goto retry;
}
#endif
// The payload of the BLACKHOLE points to the TSO
((StgInd *)bh)->indirectee = (StgClosure *)tso;
write_barrier();
SET_INFO(bh,&stg_BLACKHOLE_info);
// .. and we need a write barrier, since we just mutated the closure:
recordClosureMutated(cap,bh);
// We pretend that bh has just been created.
LDV_RECORD_CREATE(bh);
frame = (StgClosure *) ((StgUpdateFrame *)frame + 1);
if (prev_was_update_frame) {
words_to_squeeze += sizeofW(StgUpdateFrame);
weight += weight_pending;
weight_pending = 0;
}
prev_was_update_frame = true;
break;
case UNDERFLOW_FRAME:
case STOP_FRAME:
goto end;
// normal stack frames; do nothing except advance the pointer
default:
{
uint32_t frame_size = stack_frame_sizeW(frame);
weight_pending += frame_size;
frame = (StgClosure *)((StgPtr)frame + frame_size);
prev_was_update_frame = false;
}
}
}
end:
// Should we squeeze or not? Arbitrary heuristic: we squeeze if
// the number of words we have to shift down is less than the
// number of stack words we squeeze away by doing so.
// The threshold was bumped from 5 to 8 as a result of #2797
heuristic_says_squeeze = ((weight <= 8 && words_to_squeeze > 0)
|| weight < words_to_squeeze);
debugTrace(DEBUG_squeeze,
"words_to_squeeze: %d, weight: %d, squeeze: %s",
words_to_squeeze, weight,
heuristic_says_squeeze ? "YES" : "NO");
if (RtsFlags.GcFlags.squeezeUpdFrames == true &&
heuristic_says_squeeze) {
stackSqueeze(cap, tso, (StgPtr)frame);
tso->flags |= TSO_SQUEEZED;
// This flag tells threadStackOverflow() that the stack was
// squeezed, because it may not need to be expanded.
} else {
tso->flags &= ~TSO_SQUEEZED;
}
}
void
printStackChunk( StgPtr sp, StgPtr spBottom )
{
StgWord bitmap;
const StgInfoTable *info;
ASSERT(sp <= spBottom);
for (; sp < spBottom; sp += stack_frame_sizeW((StgClosure *)sp)) {
info = get_itbl((StgClosure *)sp);
switch (info->type) {
case UPDATE_FRAME:
case CATCH_FRAME:
case UNDERFLOW_FRAME:
case STOP_FRAME:
printObj((StgClosure*)sp);
continue;
case RET_DYN:
{
StgRetDyn* r;
StgPtr p;
StgWord dyn;
nat size;
r = (StgRetDyn *)sp;
dyn = r->liveness;
debugBelch("RET_DYN (%p)\n", r);
p = (P_)(r->payload);
printSmallBitmap(spBottom, sp,
RET_DYN_LIVENESS(r->liveness),
RET_DYN_BITMAP_SIZE);
p += RET_DYN_BITMAP_SIZE + RET_DYN_NONPTR_REGS_SIZE;
for (size = RET_DYN_NONPTRS(dyn); size > 0; size--) {
debugBelch(" stk[%ld] (%p) = ", (long)(spBottom-p), p);
debugBelch("Word# %ld\n", (long)*p);
p++;
}
for (size = RET_DYN_PTRS(dyn); size > 0; size--) {
debugBelch(" stk[%ld] (%p) = ", (long)(spBottom-p), p);
printPtr(p);
p++;
}
continue;
}
case RET_SMALL:
debugBelch("RET_SMALL (%p)\n", info);
bitmap = info->layout.bitmap;
printSmallBitmap(spBottom, sp+1,
BITMAP_BITS(bitmap), BITMAP_SIZE(bitmap));
continue;
case RET_BCO: {
StgBCO *bco;
bco = ((StgBCO *)sp[1]);
debugBelch("RET_BCO (%p)\n", sp);
printLargeBitmap(spBottom, sp+2,
BCO_BITMAP(bco), BCO_BITMAP_SIZE(bco));
continue;
}
case RET_BIG:
barf("todo");
case RET_FUN:
{
StgFunInfoTable *fun_info;
StgRetFun *ret_fun;
ret_fun = (StgRetFun *)sp;
fun_info = get_fun_itbl(ret_fun->fun);
debugBelch("RET_FUN (%p) (type=%d)\n", ret_fun->fun, (int)fun_info->f.fun_type);
switch (fun_info->f.fun_type) {
case ARG_GEN:
printSmallBitmap(spBottom, sp+2,
BITMAP_BITS(fun_info->f.b.bitmap),
BITMAP_SIZE(fun_info->f.b.bitmap));
break;
case ARG_GEN_BIG:
printLargeBitmap(spBottom, sp+2,
GET_FUN_LARGE_BITMAP(fun_info),
GET_FUN_LARGE_BITMAP(fun_info)->size);
break;
default:
printSmallBitmap(spBottom, sp+2,
BITMAP_BITS(stg_arg_bitmaps[fun_info->f.fun_type]),
BITMAP_SIZE(stg_arg_bitmaps[fun_info->f.fun_type]));
break;
}
continue;
}
default:
debugBelch("unknown object %d\n", (int)info->type);
barf("printStackChunk");
}
}
}
void
printStackChunk( StgPtr sp, StgPtr spBottom )
{
StgWord bitmap;
const StgInfoTable *info;
ASSERT(sp <= spBottom);
for (; sp < spBottom; sp += stack_frame_sizeW((StgClosure *)sp)) {
info = get_itbl((StgClosure *)sp);
switch (info->type) {
case UPDATE_FRAME:
case CATCH_FRAME:
case UNDERFLOW_FRAME:
case STOP_FRAME:
printObj((StgClosure*)sp);
continue;
case RET_SMALL:
debugBelch("RET_SMALL (%p)\n", info);
bitmap = info->layout.bitmap;
printSmallBitmap(spBottom, sp+1,
BITMAP_BITS(bitmap), BITMAP_SIZE(bitmap));
continue;
case RET_BCO: {
StgBCO *bco;
bco = ((StgBCO *)sp[1]);
debugBelch("RET_BCO (%p)\n", sp);
printLargeBitmap(spBottom, sp+2,
BCO_BITMAP(bco), BCO_BITMAP_SIZE(bco));
continue;
}
case RET_BIG:
barf("todo");
case RET_FUN:
{
StgFunInfoTable *fun_info;
StgRetFun *ret_fun;
ret_fun = (StgRetFun *)sp;
fun_info = get_fun_itbl(ret_fun->fun);
debugBelch("RET_FUN (%p) (type=%d)\n", ret_fun->fun, (int)fun_info->f.fun_type);
switch (fun_info->f.fun_type) {
case ARG_GEN:
printSmallBitmap(spBottom, sp+2,
BITMAP_BITS(fun_info->f.b.bitmap),
BITMAP_SIZE(fun_info->f.b.bitmap));
break;
case ARG_GEN_BIG:
printLargeBitmap(spBottom, sp+2,
GET_FUN_LARGE_BITMAP(fun_info),
GET_FUN_LARGE_BITMAP(fun_info)->size);
break;
default:
printSmallBitmap(spBottom, sp+2,
BITMAP_BITS(stg_arg_bitmaps[fun_info->f.fun_type]),
BITMAP_SIZE(stg_arg_bitmaps[fun_info->f.fun_type]));
break;
}
continue;
}
default:
debugBelch("unknown object %d\n", (int)info->type);
barf("printStackChunk");
}
}
}
