diff options
Diffstat (limited to 'rts/PrimOps.cmm')
| -rw-r--r-- | rts/PrimOps.cmm | 79 |
1 files changed, 76 insertions, 3 deletions
diff --git a/rts/PrimOps.cmm b/rts/PrimOps.cmm index a227e776a7..63babd04f2 100644 --- a/rts/PrimOps.cmm +++ b/rts/PrimOps.cmm @@ -1433,7 +1433,7 @@ loop: goto loop; } - // There are takeMVar(s) waiting: wake up the first one + // There are atomicReadMVar/takeMVar(s) waiting: wake up the first one tso = StgMVarTSOQueue_tso(q); StgMVar_head(mvar) = StgMVarTSOQueue_link(q); @@ -1441,8 +1441,11 @@ loop: StgMVar_tail(mvar) = stg_END_TSO_QUEUE_closure; } - ASSERT(StgTSO_why_blocked(tso) == BlockedOnMVar::I16); ASSERT(StgTSO_block_info(tso) == mvar); + // save why_blocked here, because waking up the thread destroys + // this information + W_ why_blocked; + why_blocked = TO_W_(StgTSO_why_blocked(tso)); // actually perform the takeMVar W_ stack; @@ -1458,6 +1461,15 @@ loop: ccall tryWakeupThread(MyCapability() "ptr", tso); + // If it was an atomicReadMVar, then we can still do work, + // so loop back. (XXX: This could take a while) + if (why_blocked == BlockedOnMVarRead) { + q = StgMVarTSOQueue_link(q); + goto loop; + } + + ASSERT(why_blocked == BlockedOnMVar); + unlockClosure(mvar, info); return (); } @@ -1512,8 +1524,11 @@ loop: StgMVar_tail(mvar) = stg_END_TSO_QUEUE_closure; } - ASSERT(StgTSO_why_blocked(tso) == BlockedOnMVar::I16); ASSERT(StgTSO_block_info(tso) == mvar); + // save why_blocked here, because waking up the thread destroys + // this information + W_ why_blocked; + why_blocked = TO_W_(StgTSO_why_blocked(tso)); // actually perform the takeMVar W_ stack; @@ -1529,10 +1544,68 @@ loop: ccall tryWakeupThread(MyCapability() "ptr", tso); + // If it was an atomicReadMVar, then we can still do work, + // so loop back. (XXX: This could take a while) + if (why_blocked == BlockedOnMVarRead) { + q = StgMVarTSOQueue_link(q); + goto loop; + } + + ASSERT(why_blocked == BlockedOnMVar); + unlockClosure(mvar, info); return (1); } +stg_atomicReadMVarzh ( P_ mvar, /* :: MVar a */ ) +{ + W_ val, info, tso, q; + +#if defined(THREADED_RTS) + ("ptr" info) = ccall lockClosure(mvar "ptr"); +#else + info = GET_INFO(mvar); +#endif + + if (info == stg_MVAR_CLEAN_info) { + ccall dirty_MVAR(BaseReg "ptr", mvar "ptr"); + } + + /* If the MVar is empty, put ourselves on the blocked readers + * list and wait until we're woken up. + */ + if (StgMVar_value(mvar) == stg_END_TSO_QUEUE_closure) { + + ALLOC_PRIM_WITH_CUSTOM_FAILURE + (SIZEOF_StgMVarTSOQueue, + unlockClosure(mvar, stg_MVAR_DIRTY_info); + GC_PRIM_P(stg_atomicReadMVarzh, mvar)); + + q = Hp - SIZEOF_StgMVarTSOQueue + WDS(1); + + // readMVars are pushed to the front of the queue, so + // they get handled immediately + SET_HDR(q, stg_MVAR_TSO_QUEUE_info, CCS_SYSTEM); + StgMVarTSOQueue_link(q) = StgMVar_head(mvar); + StgMVarTSOQueue_tso(q) = CurrentTSO; + + StgTSO__link(CurrentTSO) = q; + StgTSO_block_info(CurrentTSO) = mvar; + StgTSO_why_blocked(CurrentTSO) = BlockedOnMVarRead::I16; + StgMVar_head(mvar) = q; + + if (StgMVar_tail(mvar) == stg_END_TSO_QUEUE_closure) { + StgMVar_tail(mvar) = q; + } + + jump stg_block_atomicreadmvar(mvar); + } + + val = StgMVar_value(mvar); + + unlockClosure(mvar, stg_MVAR_DIRTY_info); + return (val); +} /* ----------------------------------------------------------------------------- Stable pointer primitives |