由于地图功能导致的内存泄漏 [英] Thunk memory leak as a result of map function

问题描述

我正在编写一个多线程程序，它非常适用于mvars;在这种情况下，我有一个线程周期性地改变mvar中的列表。不幸的是，有一个thunk内存泄漏。似乎有一个问题，'地图id'（在真正的程序中，我使用的是别的东西而不是id）函数泄漏。我无法找到如何避免这种情况的方法 - 我在玩'seq'而没有结果。什么是正确的方法来解决泄漏？

  upgraderThread :: MVar [ChannelInfo]  - > IO（）
 upgraderThread chanMVar = forever job 
其中
 job = do 
 threadDelay 1000 
 vlist<  -  takeMVar chanMVar 
 let reslist = map id vlist 
 putMVar chanMVar reslist 
  

解决方案

尝试，这似乎工作：

pre $ upgraderThread chanMVar =永远工作
其中
工作=做
threadDelay 1000
vlist< - takeMVar chanMVar
let！reslist = strictList $ map id vlist
putMVar chanMVar reslist
$ b $ strictList xs =如果所有p xs那么xs else []
其中px = x`seq` True


I am writing a multi-threaded program that makes quite a use of mvars; in this case I have a thread that periodically changes list inside an mvar. Unfortunately, there is a thunk memory leak. There seems to be aproblem that the 'map id' (in real program I use something else than id) function leaks. I just cannot find a way how to avoid that - I was playing with 'seq' with no result. What is the right way to fix the leak?

upgraderThread :: MVar [ChannelInfo] -> IO ()
upgraderThread chanMVar = forever job
    where
        job = do
            threadDelay 1000
            vlist <- takeMVar chanMVar
            let reslist = map id vlist
            putMVar chanMVar reslist

解决方案

After a few more tries, this one seems to work:

upgraderThread chanMVar = forever job
    where
        job = do
            threadDelay 1000
            vlist <- takeMVar chanMVar
            let !reslist = strictList $ map id vlist
            putMVar chanMVar reslist

        strictList xs = if all p xs then xs else []
            where p x = x `seq` True        

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