diff options
| -rw-r--r-- | includes/rts/storage/ClosureMacros.h | 31 |
1 files changed, 26 insertions, 5 deletions
diff --git a/includes/rts/storage/ClosureMacros.h b/includes/rts/storage/ClosureMacros.h index 15146c0592..0043145c3f 100644 --- a/includes/rts/storage/ClosureMacros.h +++ b/includes/rts/storage/ClosureMacros.h @@ -532,10 +532,11 @@ zeroSlop ( StgClosure *p, uint32_t offset, /*< offset to start zeroing at, in words */ uint32_t size, /*< total closure size, in words */ + bool known_mutable /*< is this a closure who's slop we can always zero? */ ); EXTERN_INLINE void -zeroSlop (StgClosure *p, uint32_t offset, uint32_t size) +zeroSlop (StgClosure *p, uint32_t offset, uint32_t size, bool known_mutable) { // see Note [zeroing slop when overwriting closures], also #8402 @@ -555,7 +556,27 @@ zeroSlop (StgClosure *p, uint32_t offset, uint32_t size) const bool zero_slop_immutable = want_to_zero_immutable_slop && can_zero_immutable_slop; - if(!zero_slop_immutable) + const bool zero_slop_mutable = +#if defined(PROFILING) + // Always zero mutable closure slop when profiling. We do this to cover + // the case of shrinking mutable arrays in pinned blocks for the heap + // profiler, see Note [skipping slop in the heap profiler] + // + // TODO: We could make this check more specific and only zero if the + // object is in a BF_PINNED bdescr here. Update Note [slop on the heap] + // and [zeroing slop when overwriting closures] if you change this. + true +#else + zero_slop_immutable +#endif + ; + + const bool zero_slop = + // If we're not sure this is a mutable closure treat it like an + // immutable one. + known_mutable ? zero_slop_mutable : zero_slop_immutable; + + if(!zero_slop) return; for (uint32_t i = offset; i < size; i++) { @@ -571,7 +592,7 @@ EXTERN_INLINE void overwritingClosure (StgClosure *p) if(era > 0 && !isInherentlyUsed(get_itbl(p)->type)) LDV_recordDead(p, size); #endif - zeroSlop(p, sizeofW(StgThunkHeader), size); + zeroSlop(p, sizeofW(StgThunkHeader), size, /*known_mutable=*/false); } // Version of 'overwritingClosure' which overwrites only a suffix of a @@ -595,7 +616,7 @@ overwritingMutableClosureOfs (StgClosure *p, uint32_t offset) #if defined(PROFILING) ASSERT(isInherentlyUsed(get_itbl(p)->type) == true); #endif - zeroSlop(p, offset, closure_sizeW(p)); + zeroSlop(p, offset, closure_sizeW(p), /*known_mutable=*/true); } // Version of 'overwritingClosure' which takes closure size as argument. @@ -609,5 +630,5 @@ EXTERN_INLINE void overwritingClosureSize (StgClosure *p, uint32_t size) if(era > 0) LDV_recordDead(p, size); #endif - zeroSlop(p, sizeofW(StgThunkHeader), size); + zeroSlop(p, sizeofW(StgThunkHeader), size, /*known_mutable=*/false); } |