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| author | Joey Hess <joeyh@joeyh.name> | 2019-06-05 19:43:32 -0400 |
|---|---|---|
| committer | Joey Hess <joeyh@joeyh.name> | 2019-06-05 20:07:35 -0400 |
| commit | 4932972487ec89b2b257336d943b569cb9767942 (patch) | |
| tree | b56f80f0417a120e065bab7ff69b19e909dd9793 /Types/WorkerPool.hs | |
| parent | 3eac4e01a4db5a6da63b5ee61944c20c5e855010 (diff) | |
fix STM deadlock
659640e22493cc39a2351a4d0d7ac575b0ff3b7a was buggy, it had a STM
deadlock because two actions both wanted to takeTMVar the WorkerPool
and so blocked one-another.
Fixed by completely reworking how the pool is maintained. Maintenace
threads now wait for the Async actions and update the WorkerPool. This
means twice as many threads as before, but green threads so will only
use a few extra bytes ram per thread.
Diffstat (limited to 'Types/WorkerPool.hs')
| -rw-r--r-- | Types/WorkerPool.hs | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/Types/WorkerPool.hs b/Types/WorkerPool.hs index 03a95b47ba..a2b7131bf4 100644 --- a/Types/WorkerPool.hs +++ b/Types/WorkerPool.hs @@ -67,3 +67,14 @@ removeThreadIdWorkerPool tid (WorkerPool l) = go [] l go c (ActiveWorker a stage : rest) | asyncThreadId a == tid = Just ((a, stage), WorkerPool (c++rest)) go c (v : rest) = go (v:c) rest + +deactivateWorker :: WorkerPool t -> Async t -> t -> WorkerPool t +deactivateWorker UnallocatedWorkerPool _ _ = UnallocatedWorkerPool +deactivateWorker (WorkerPool l) aid t = WorkerPool $ go l + where + go [] = [] + go (w@(IdleWorker _ _) : rest) = w : go rest + go (w@(ActiveWorker a st) : rest) + | a == aid = IdleWorker t st : rest + | otherwise = w : go rest + |