Per-thread allocation counters and limits

This tracks the amount of memory allocation by each thread in a
counter stored in the TSO.  Optionally, when the counter drops below
zero (it counts down), the thread can be sent an asynchronous
exception: AllocationLimitExceeded.  When this happens, given a small
additional limit so that it can handle the exception.  See
documentation in GHC.Conc for more details.

Allocation limits are similar to timeouts, but

  - timeouts use real time, not CPU time.  Allocation limits do not
    count anything while the thread is blocked or in foreign code.

  - timeouts don't re-trigger if the thread catches the exception,
    allocation limits do.

  - timeouts can catch non-allocating loops, if you use
    -fno-omit-yields.  This doesn't work for allocation limits.

I couldn't measure any impact on benchmarks with these changes, even
for nofib/smp.

1 files changed, 1 insertions, 0 deletions

diff --git a/rts/RtsStartup.c b/rts/RtsStartup.c
index aa7306f88a..640811ff17 100644
--- a/rts/RtsStartup.c
+++ b/rts/RtsStartup.c
@@ -208,6 +208,7 @@ hs_init_ghc(int *argc, char **argv[], RtsConfig rts_config)
     getStablePtr((StgPtr)blockedIndefinitelyOnMVar_closure);
     getStablePtr((StgPtr)nonTermination_closure);
     getStablePtr((StgPtr)blockedIndefinitelyOnSTM_closure);
+    getStablePtr((StgPtr)allocationLimitExceeded_closure);
     getStablePtr((StgPtr)nestedAtomically_closure);
 
     getStablePtr((StgPtr)runSparks_closure);