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| author | Simon Marlow <smarlow@fb.com> | 2016-10-28 08:30:14 -0700 |
|---|---|---|
| committer | Simon Marlow <marlowsd@gmail.com> | 2016-10-29 19:33:52 +0100 |
| commit | 4e088b497edd83f361898fa9d2d62ff310b08945 (patch) | |
| tree | f0ef3a8f2443cec7dcdce15493fd8ad92e197997 /rts/sm/GCThread.h | |
| parent | 4b300a32257c3ed272747f7e75709a26dd2d8407 (diff) | |
| download | haskell-4e088b497edd83f361898fa9d2d62ff310b08945.tar.gz | |
Fix a bug in parallel GC synchronisation
Summary:
The problem boils down to global variables: in particular gc_threads[],
which was being modified by a subsequent GC before the previous GC had
finished with it. The fix is to not use global variables.
This was causing setnumcapabilities001 to fail (again!). It's an old
bug though.
Test Plan:
Ran setnumcapabilities001 in a loop for a couple of hours. Before this
patch it had been failing after a few minutes. Not a very scientific
test, but it's the best I have.
Reviewers: bgamari, austin, fryguybob, niteria, erikd
Subscribers: thomie
Differential Revision: https://phabricator.haskell.org/D2654
Diffstat (limited to 'rts/sm/GCThread.h')
| -rw-r--r-- | rts/sm/GCThread.h | 10 |
1 files changed, 4 insertions, 6 deletions
diff --git a/rts/sm/GCThread.h b/rts/sm/GCThread.h index b728315554..f940263665 100644 --- a/rts/sm/GCThread.h +++ b/rts/sm/GCThread.h @@ -6,7 +6,7 @@ * * Documentation on the architecture of the Garbage Collector can be * found in the online commentary: - * + * * http://ghc.haskell.org/trac/ghc/wiki/Commentary/Rts/Storage/GC * * ---------------------------------------------------------------------------*/ @@ -21,7 +21,7 @@ /* ----------------------------------------------------------------------------- General scheme - + ToDo: move this to the wiki when the implementation is done. We're only going to try to parallelise the copying GC for now. The @@ -67,13 +67,13 @@ /* ----------------------------------------------------------------------------- Generation Workspace - + A generation workspace exists for each generation for each GC thread. The GC thread takes a block from the todos list of the generation into the scanbd and then scans it. Objects referred to by those in the scan block are copied into the todo or scavd blocks of the relevant generation. - + ------------------------------------------------------------------------- */ typedef struct gen_workspace_ { @@ -127,7 +127,6 @@ typedef struct gc_thread_ { volatile StgWord wakeup; // NB not StgWord8; only StgWord is guaranteed atomic #endif uint32_t thread_index; // a zero based index identifying the thread - rtsBool idle; // sitting out of this GC cycle bdescr * free_blocks; // a buffer of free blocks for this thread // during GC without accessing the block @@ -211,4 +210,3 @@ extern ThreadLocalKey gctKey; #include "EndPrivate.h" #endif // SM_GCTHREAD_H - |