diff options
Diffstat (limited to 'lib/system/threads.nim')
| -rwxr-xr-x | lib/system/threads.nim | 120 |
1 files changed, 3 insertions, 117 deletions
diff --git a/lib/system/threads.nim b/lib/system/threads.nim index 39e5d3908..4ec1239a9 100755 --- a/lib/system/threads.nim +++ b/lib/system/threads.nim @@ -21,6 +21,8 @@ ## ## .. code-block:: nimrod ## +## import locks +## ## var ## thr: array [0..4, TThread[tuple[a,b: int]]] ## L: TLock @@ -39,8 +41,6 @@ const maxRegisters = 256 # don't think there is an arch with more registers - maxLocksPerThread = 10 ## max number of locks a thread can hold - ## at the same time useStackMaskHack = false ## use the stack mask hack for better performance StackGuardSize = 4096 ThreadStackMask = 1024*256*sizeof(int)-1 @@ -251,7 +251,7 @@ when not defined(useNimRtl): type TThread* {.pure, final.}[TMsg] = object of TGcThread ## Nimrod thread. A thread is a heavy object (~14K) - ## that should not be part of a message! Use + ## that **must not** be part of a message! Use ## a ``TThreadId`` for that. emptyFn: proc () dataFn: proc (m: TMsg) @@ -395,120 +395,6 @@ when useStackMaskHack: createThread(mainThread, tp) joinThread(mainThread) -# --------------------------- lock handling ---------------------------------- - -type - TLock* = TSysLock ## Nimrod lock; whether this is re-entrant - ## or not is unspecified! - -const - noDeadlocks = false # compileOption("deadlockPrevention") - -when false: - var - deadlocksPrevented*: int ## counts the number of times a - ## deadlock has been prevented - locksLen {.threadvar.}: int - locks {.threadvar.}: array [0..MaxLocksPerThread-1, pointer] - - proc OrderedLocks(): bool = - for i in 0 .. locksLen-2: - if locks[i] >= locks[i+1]: return false - result = true - -proc InitLock*(lock: var TLock) {.inline.} = - ## Initializes the lock `lock`. - InitSysLock(lock) - -proc TryAcquire*(lock: var TLock): bool {.inline.} = - ## Try to acquires the lock `lock`. Returns `true` on success. - result = TryAcquireSys(lock) - when noDeadlocks: - if not result: return - # we have to add it to the ordered list. Oh, and we might fail if - # there is no space in the array left ... - if locksLen >= len(locks): - ReleaseSys(lock) - raise newException(EResourceExhausted, "cannot acquire additional lock") - # find the position to add: - var p = addr(lock) - var L = locksLen-1 - var i = 0 - while i <= L: - sysAssert locks[i] != nil - if locks[i] < p: inc(i) # in correct order - elif locks[i] == p: return # thread already holds lock - else: - # do the crazy stuff here: - while L >= i: - locks[L+1] = locks[L] - dec L - locks[i] = p - inc(locksLen) - sysAssert OrderedLocks() - return - # simply add to the end: - locks[locksLen] = p - inc(locksLen) - sysAssert OrderedLocks(g) - -proc Acquire*(lock: var TLock) = - ## Acquires the lock `lock`. - when nodeadlocks: - var p = addr(lock) - var L = locksLen-1 - var i = 0 - while i <= L: - sysAssert locks[i] != nil - if locks[i] < p: inc(i) # in correct order - elif locks[i] == p: return # thread already holds lock - else: - # do the crazy stuff here: - if locksLen >= len(locks): - raise newException(EResourceExhausted, - "cannot acquire additional lock") - while L >= i: - ReleaseSys(cast[ptr TSysLock](locks[L])[]) - locks[L+1] = locks[L] - dec L - # acquire the current lock: - AcquireSys(lock) - locks[i] = p - inc(locksLen) - # acquire old locks in proper order again: - L = locksLen-1 - inc i - while i <= L: - AcquireSys(cast[ptr TSysLock](locks[i])[]) - inc(i) - # DANGER: We can only modify this global var if we gained every lock! - # NO! We need an atomic increment. Crap. - discard system.atomicInc(deadlocksPrevented, 1) - sysAssert OrderedLocks(g) - return - - # simply add to the end: - if locksLen >= len(locks): - raise newException(EResourceExhausted, "cannot acquire additional lock") - AcquireSys(lock) - locks[locksLen] = p - inc(locksLen) - sysAssert OrderedLocks(g) - else: - AcquireSys(lock) - -proc Release*(lock: var TLock) = - ## Releases the lock `lock`. - when nodeadlocks: - var p = addr(lock) - var L = locksLen - for i in countdown(L-1, 0): - if locks[i] == p: - for j in i..L-2: locks[j] = locks[j+1] - dec locksLen - break - ReleaseSys(lock) - # ------------------------ message passing support --------------------------- proc getInBoxMem[TMsg](t: var TThread[TMsg]): pointer {.inline.} = |