Repository : ssh://darcs.haskell.org//srv/darcs/ghc On branch : ghc-7.6
http://hackage.haskell.org/trac/ghc/changeset/4709d3e1c493536e6e3058ae15de0d86c01e417a >--------------------------------------------------------------- commit 4709d3e1c493536e6e3058ae15de0d86c01e417a Author: Simon Marlow <[email protected]> Date: Mon Aug 20 13:52:07 2012 +0100 Retain ordering of finalizers during GC (#7160) This came up since the addition of C finalizers, since Haskell finalizers are already stored in an explicit list. C finalizers on the other hand get a WEAK object each, so in order to run them in the right order we have to make sure that list stays in the correct order. I hate adding new invariants, but this is the quickest way to fix the bug for now. A better way to fix it would be to have a single WEAK object with a list of finaliers attached to it, and a primop for adding finalizers to the list. MERGED from commit cec899d9fb668d4adccf731a63902e5be49f0660 >--------------------------------------------------------------- rts/sm/MarkWeak.c | 19 ++++++++++++++----- 1 files changed, 14 insertions(+), 5 deletions(-) diff --git a/rts/sm/MarkWeak.c b/rts/sm/MarkWeak.c index f9275ec..b7d6226 100644 --- a/rts/sm/MarkWeak.c +++ b/rts/sm/MarkWeak.c @@ -78,6 +78,7 @@ static WeakStage weak_stage; /* Weak pointers */ StgWeak *old_weak_ptr_list; // also pending finaliser list +StgWeak *weak_ptr_list_tail; // List of threads found to be unreachable StgTSO *resurrected_threads; @@ -90,6 +91,7 @@ initWeakForGC(void) { old_weak_ptr_list = weak_ptr_list; weak_ptr_list = NULL; + weak_ptr_list_tail = NULL; weak_stage = WeakPtrs; resurrected_threads = END_TSO_QUEUE; } @@ -139,11 +141,18 @@ traverseWeakPtrList(void) evacuate(&w->finalizer); // remove this weak ptr from the old_weak_ptr list *last_w = w->link; - // and put it on the new weak ptr list - next_w = w->link; - w->link = weak_ptr_list; - weak_ptr_list = w; - flag = rtsTrue; + next_w = w->link; + + // and put it on the new weak ptr list. + // NB. we must retain the order of the weak_ptr_list (#7160) + if (weak_ptr_list == NULL) { + weak_ptr_list = w; + } else { + weak_ptr_list_tail->link = w; + } + weak_ptr_list_tail = w; + w->link = NULL; + flag = rtsTrue; debugTrace(DEBUG_weak, "weak pointer still alive at %p -> %p", _______________________________________________ Cvs-ghc mailing list [email protected] http://www.haskell.org/mailman/listinfo/cvs-ghc
