From 0d93247359531388f88f22f85326e1142d801e85 Mon Sep 17 00:00:00 2001 From: Monty Brandenberg Date: Tue, 6 Aug 2013 18:05:34 -0400 Subject: SH-4411 Thread/mutex rework between main and worker thread Have the ::notifyLoadedMeshes() method doing correct locking and stall avoidance at the same time. This method now does lazy mutex lock acquisition (trylock()) and if it fails on either, it gives up and comes back later. Capture the maximum number of sequential failures and report this at the end of the run in the log. (So far, with big mesh regions, I've only seen 1s and 2s.) Locking/mutex requirements sorted in other locations as well. LLMutex gets trylock() method as well as new LLMutexTrylock scoped locking class. Clean up some documentation, more to do. --- indra/llcommon/llthread.h | 46 ++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 44 insertions(+), 2 deletions(-) (limited to 'indra/llcommon/llthread.h') diff --git a/indra/llcommon/llthread.h b/indra/llcommon/llthread.h index 0fb89c5613..376df398d7 100755 --- a/indra/llcommon/llthread.h +++ b/indra/llcommon/llthread.h @@ -4,7 +4,7 @@ * * $LicenseInfo:firstyear=2004&license=viewerlgpl$ * Second Life Viewer Source Code - * Copyright (C) 2010, Linden Research, Inc. + * Copyright (C) 2010-2013, Linden Research, Inc. * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public @@ -156,7 +156,8 @@ public: virtual ~LLMutex(); void lock(); // blocks - void unlock(); + bool trylock(); // non-blocking, returns true if lock held. + void unlock(); // undefined behavior when called on mutex not being held bool isLocked(); // non-blocking, but does do a lock/unlock so not free bool isSelfLocked(); //return true if locked in a same thread U32 lockingThread() const; //get ID of locking thread @@ -174,6 +175,8 @@ protected: #endif }; +//============================================================================ + // Actually a condition/mutex pair (since each condition needs to be associated with a mutex). class LL_COMMON_API LLCondition : public LLMutex { @@ -189,6 +192,8 @@ protected: apr_thread_cond_t *mAPRCondp; }; +//============================================================================ + class LLMutexLock { public: @@ -210,6 +215,43 @@ private: //============================================================================ +// Scoped locking class similar in function to LLMutexLock but uses +// the trylock() method to conditionally acquire lock without +// blocking. Caller resolves the resulting condition by calling +// the isLocked() method and either punts or continues as indicated. +// +// Mostly of interest to callers needing to avoid stalls who can +// guarantee another attempt at a later time. + +class LLMutexTrylock +{ +public: + LLMutexTrylock(LLMutex* mutex) + : mMutex(mutex), + mLocked(false) + { + if (mMutex) + mLocked = mMutex->trylock(); + } + + ~LLMutexTrylock() + { + if (mMutex && mLocked) + mMutex->unlock(); + } + + bool isLocked() const + { + return mLocked; + } + +private: + LLMutex* mMutex; + bool mLocked; +}; + +//============================================================================ + void LLThread::lockData() { mDataLock->lock(); -- cgit v1.2.3