Commit a1e3066e authored by Simon Marlow's avatar Simon Marlow
Browse files

THREADED_RTS: use cas() when claiming thunks

I guess I forgot to do this the first time around; the upshot is that
there could be some uncaught duplication of work on a multiprocessor
(but unlikely).
parent d5b20065
......@@ -178,6 +178,8 @@ threadPaused(Capability *cap, StgTSO *tso)
{
StgClosure *frame;
StgRetInfoTable *info;
const StgInfoTable *bh_info;
const StgInfoTable *cur_bh_info USED_IF_THREADS;
StgClosure *bh;
StgPtr stack_end;
nat words_to_squeeze = 0;
......@@ -212,8 +214,13 @@ threadPaused(Capability *cap, StgTSO *tso)
SET_INFO(frame, (StgInfoTable *)&stg_marked_upd_frame_info);
bh = ((StgUpdateFrame *)frame)->updatee;
bh_info = bh->header.info;
if (closure_IND(bh) || bh->header.info == &stg_BLACKHOLE_info) {
#ifdef THREADED_RTS
retry:
#endif
if (closure_flags[INFO_PTR_TO_STRUCT(bh_info)->type] & _IND
|| bh_info == &stg_BLACKHOLE_info) {
debugTrace(DEBUG_squeeze,
"suspending duplicate work: %ld words of stack",
(long)((StgPtr)frame - tso->sp));
......@@ -246,7 +253,20 @@ threadPaused(Capability *cap, StgTSO *tso)
// We pretend that bh is now dead.
LDV_recordDead_FILL_SLOP_DYNAMIC((StgClosure *)bh);
#endif
#ifdef THREADED_RTS
cur_bh_info = (const StgInfoTable *)
cas((StgVolatilePtr)&bh->header.info,
(StgWord)bh_info,
(StgWord)&stg_BLACKHOLE_info);
if (cur_bh_info != bh_info) {
bh_info = cur_bh_info;
goto retry;
}
#else
SET_INFO(bh,&stg_BLACKHOLE_info);
#endif
// We pretend that bh has just been created.
LDV_RECORD_CREATE(bh);
......
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