diff options
Diffstat (limited to 'indra/llcommon/llcoros.cpp')
| -rw-r--r-- | indra/llcommon/llcoros.cpp | 297 |
1 files changed, 88 insertions, 209 deletions
diff --git a/indra/llcommon/llcoros.cpp b/indra/llcommon/llcoros.cpp index cc775775bf..f5ffd96cec 100644 --- a/indra/llcommon/llcoros.cpp +++ b/indra/llcommon/llcoros.cpp @@ -34,6 +34,17 @@ // std headers // external library headers #include <boost/bind.hpp> +#include <boost/fiber/fiber.hpp> +#ifndef BOOST_DISABLE_ASSERTS +#define UNDO_BOOST_DISABLE_ASSERTS +// with Boost 1.65.1, needed for Mac with this specific header +#define BOOST_DISABLE_ASSERTS +#endif +#include <boost/fiber/protected_fixedsize_stack.hpp> +#ifdef UNDO_BOOST_DISABLE_ASSERTS +#undef UNDO_BOOST_DISABLE_ASSERTS +#undef BOOST_DISABLE_ASSERTS +#endif // other Linden headers #include "lltimer.h" #include "llevents.h" @@ -45,176 +56,69 @@ #include <excpt.h> #endif -namespace { -void no_op() {} -} // anonymous namespace -// Do nothing, when we need nothing done. This is a static member of LLCoros -// because CoroData is a private nested class. -void LLCoros::no_cleanup(CoroData*) {} - -// CoroData for the currently-running coroutine. Use a thread_specific_ptr -// because each thread potentially has its own distinct pool of coroutines. -LLCoros::Current::Current() +const LLCoros::CoroData& LLCoros::get_CoroData(const std::string& caller) const { - // Use a function-static instance so this thread_specific_ptr is - // instantiated on demand. Since we happen to know it's consumed by - // LLSingleton, this is likely to happen before the runtime has finished - // initializing module-static data. For the same reason, we can't package - // this pointer in an LLSingleton. - - // This thread_specific_ptr does NOT own the CoroData object! That's owned - // by LLCoros::mCoros. It merely identifies it. For this reason we - // instantiate it with a no-op cleanup function. - static boost::thread_specific_ptr<LLCoros::CoroData> sCurrent(LLCoros::no_cleanup); - - // If this is the first time we're accessing sCurrent for the running - // thread, its get() will be NULL. This could be a problem, in that - // llcoro::get_id() would return the same (NULL) token value for the "main - // coroutine" in every thread, whereas what we really want is a distinct - // value for every distinct stack in the process. So if get() is NULL, - // give it a heap CoroData: this ensures that llcoro::get_id() will return - // distinct values. - // This tactic is "leaky": sCurrent explicitly does not destroy any - // CoroData to which it points, and we do NOT enter these "main coroutine" - // CoroData instances in the LLCoros::mCoros map. They are dummy entries, - // and they will leak at process shutdown: one CoroData per thread. - if (! sCurrent.get()) + CoroData* current = mCurrent.get(); + // For the main() coroutine, the one NOT explicitly launched by launch(), + // we never explicitly set mCurrent. Use a static CoroData instance with + // canonical values. + if (! current) { // It's tempting to provide a distinct name for each thread's "main // coroutine." But as getName() has always returned the empty string - // to mean "not in a coroutine," empty string should suffice here -- - // and truthfully the additional (thread-safe!) machinery to ensure - // uniqueness just doesn't feel worth the trouble. - // We use a no-op callable and a minimal stack size because, although - // CoroData's constructor in fact initializes its mCoro with a - // coroutine with that stack size, no one ever actually enters it by - // calling mCoro(). - sCurrent.reset(new CoroData(0, // no prev - "", // not a named coroutine - no_op, // no-op callable - 1024)); // stacksize moot + // to mean "not in a coroutine," empty string should suffice here. + static CoroData sMain(""); + // We need not reset() the local_ptr to this read-only data: reuse the + // same instance for every thread's main coroutine. + current = &sMain; } - - mCurrent = &sCurrent; + return *current; } -//static LLCoros::CoroData& LLCoros::get_CoroData(const std::string& caller) { - CoroData* current = Current(); - // With the dummy CoroData set in LLCoros::Current::Current(), this - // pointer should never be NULL. - llassert_always(current); - return *current; + // reuse const implementation, just cast away const-ness of result + return const_cast<CoroData&>(const_cast<const LLCoros*>(this)->get_CoroData(caller)); } //static -LLCoros::coro::self& LLCoros::get_self() +LLCoros::coro::id LLCoros::get_self() { - CoroData& current = get_CoroData("get_self()"); - if (! current.mSelf) - { - LL_ERRS("LLCoros") << "Calling get_self() from non-coroutine context!" << LL_ENDL; - } - return *current.mSelf; + return boost::this_fiber::get_id(); } //static void LLCoros::set_consuming(bool consuming) { - get_CoroData("set_consuming()").mConsuming = consuming; + CoroData& data(LLCoros::instance().get_CoroData("set_consuming()")); + // DO NOT call this on the main() coroutine. + llassert_always(! data.mName.empty()); + data.mConsuming = consuming; } //static bool LLCoros::get_consuming() { - return get_CoroData("get_consuming()").mConsuming; -} - -llcoro::Suspending::Suspending() -{ - LLCoros::Current current; - // Remember currently-running coroutine: we're about to suspend it. - mSuspended = current; - // Revert Current to the value it had at the moment we last switched - // into this coroutine. - current.reset(mSuspended->mPrev); -} - -llcoro::Suspending::~Suspending() -{ - LLCoros::Current current; - // Okay, we're back, update our mPrev - mSuspended->mPrev = current; - // and reinstate our Current. - current.reset(mSuspended); + return LLCoros::instance().get_CoroData("get_consuming()").mConsuming; } LLCoros::LLCoros(): // MAINT-2724: default coroutine stack size too small on Windows. // Previously we used // boost::context::guarded_stack_allocator::default_stacksize(); - // empirically this is 64KB on Windows and Linux. Try quadrupling. + // empirically this is insufficient. #if ADDRESS_SIZE == 64 mStackSize(512*1024) #else mStackSize(256*1024) #endif { - // Register our cleanup() method for "mainloop" ticks - LLEventPumps::instance().obtain("mainloop").listen( - "LLCoros", boost::bind(&LLCoros::cleanup, this, _1)); -} - -bool LLCoros::cleanup(const LLSD&) -{ - static std::string previousName; - static int previousCount = 0; - // Walk the mCoros map, checking and removing completed coroutines. - for (CoroMap::iterator mi(mCoros.begin()), mend(mCoros.end()); mi != mend; ) - { - // Has this coroutine exited (normal return, exception, exit() call) - // since last tick? - if (mi->second->mCoro.exited()) - { - if (previousName != mi->first) - { - previousName = mi->first; - previousCount = 1; - } - else - { - ++previousCount; - } - - if ((previousCount < 5) || !(previousCount % 50)) - { - if (previousCount < 5) - LL_DEBUGS("LLCoros") << "LLCoros: cleaning up coroutine " << mi->first << LL_ENDL; - else - LL_DEBUGS("LLCoros") << "LLCoros: cleaning up coroutine " << mi->first << "("<< previousCount << ")" << LL_ENDL; - - } - // The erase() call will invalidate its passed iterator value -- - // so increment mi FIRST -- but pass its original value to - // erase(). This is what postincrement is all about. - mCoros.erase(mi++); - } - else - { - // Still live, just skip this entry as if incrementing at the top - // of the loop as usual. - ++mi; - } - } - return false; } std::string LLCoros::generateDistinctName(const std::string& prefix) const { - static std::string previousName; - static int previousCount = 0; + static int unique = 0; // Allowing empty name would make getName()'s not-found return ambiguous. if (prefix.empty()) @@ -225,37 +129,15 @@ std::string LLCoros::generateDistinctName(const std::string& prefix) const // If the specified name isn't already in the map, just use that. std::string name(prefix); - // Find the lowest numeric suffix that doesn't collide with an existing - // entry. Start with 2 just to make it more intuitive for any interested - // parties: e.g. "joe", "joe2", "joe3"... - for (int i = 2; ; name = STRINGIZE(prefix << i++)) + // Until we find an unused name, append a numeric suffix for uniqueness. + while (mCoros.find(name) != mCoros.end()) { - if (mCoros.find(name) == mCoros.end()) - { - if (previousName != name) - { - previousName = name; - previousCount = 1; - } - else - { - ++previousCount; - } - - if ((previousCount < 5) || !(previousCount % 50)) - { - if (previousCount < 5) - LL_DEBUGS("LLCoros") << "LLCoros: launching coroutine " << name << LL_ENDL; - else - LL_DEBUGS("LLCoros") << "LLCoros: launching coroutine " << name << "(" << previousCount << ")" << LL_ENDL; - - } - - return name; - } + name = STRINGIZE(prefix << unique++); } + return name; } +/*==========================================================================*| bool LLCoros::kill(const std::string& name) { CoroMap::iterator found = mCoros.find(name); @@ -269,10 +151,11 @@ bool LLCoros::kill(const std::string& name) mCoros.erase(found); return true; } +|*==========================================================================*/ std::string LLCoros::getName() const { - return Current()->mName; + return get_CoroData("getName()").mName; } void LLCoros::setStackSize(S32 stacksize) @@ -300,6 +183,27 @@ void LLCoros::printActiveCoroutines() } } +std::string LLCoros::launch(const std::string& prefix, const callable_t& callable) +{ + std::string name(generateDistinctName(prefix)); + // 'dispatch' means: enter the new fiber immediately, returning here only + // when the fiber yields for whatever reason. + // std::allocator_arg is a flag to indicate that the following argument is + // a StackAllocator. + // protected_fixedsize_stack sets a guard page past the end of the new + // stack so that stack underflow will result in an access violation + // instead of weird, subtle, possibly undiagnosed memory stomps. + boost::fibers::fiber newCoro(boost::fibers::launch::dispatch, + std::allocator_arg, + boost::fibers::protected_fixedsize_stack(mStackSize), + [this, &name, &callable](){ toplevel(name, callable); }); + // You have two choices with a fiber instance: you can join() it or you + // can detach() it. If you try to destroy the instance before doing + // either, the program silently terminates. We don't need this handle. + newCoro.detach(); + return name; +} + #if LL_WINDOWS static const U32 STATUS_MSC_EXCEPTION = 0xE06D7363; // compiler specific @@ -340,10 +244,14 @@ void LLCoros::winlevel(const callable_t& callable) // Top-level wrapper around caller's coroutine callable. This function accepts // the coroutine library's implicit coro::self& parameter and saves it, but // does not pass it down to the caller's callable. -void LLCoros::toplevel(coro::self& self, CoroData* data, const callable_t& callable) +void LLCoros::toplevel(const std::string& name, const callable_t& callable) { - // capture the 'self' param in CoroData - data->mSelf = &self; + CoroData* corodata = new CoroData(name); + // Store it in our pointer map. Oddly, must cast away const-ness of key. + mCoros.insert(const_cast<std::string&>(name), corodata); + // also set it as current + mCurrent.reset(corodata); + // run the code the caller actually wants in the coroutine try { @@ -358,70 +266,41 @@ void LLCoros::toplevel(coro::self& self, CoroData* data, const callable_t& calla // Any uncaught exception derived from LLContinueError will be caught // here and logged. This coroutine will terminate but the rest of the // viewer will carry on. - LOG_UNHANDLED_EXCEPTION(STRINGIZE("coroutine " << data->mName)); + LOG_UNHANDLED_EXCEPTION(STRINGIZE("coroutine " << corodata->mName)); } catch (...) { // Any OTHER kind of uncaught exception will cause the viewer to // crash, hopefully informatively. - CRASH_ON_UNHANDLED_EXCEPTION(STRINGIZE("coroutine " << data->mName)); + CRASH_ON_UNHANDLED_EXCEPTION(STRINGIZE("coroutine " << corodata->mName)); } - // This cleanup isn't perfectly symmetrical with the way we initially set - // data->mPrev, but this is our last chance to reset Current. - Current().reset(data->mPrev); } -/***************************************************************************** -* MUST BE LAST -*****************************************************************************/ -// Turn off MSVC optimizations for just LLCoros::launch() -- see -// DEV-32777. But MSVC doesn't support push/pop for optimization flags as it -// does for warning suppression, and we really don't want to force -// optimization ON for other code even in Debug or RelWithDebInfo builds. - -#if LL_MSVC -// work around broken optimizations -#pragma warning(disable: 4748) -#pragma warning(disable: 4355) // 'this' used in initializer list: yes, intentionally -#pragma optimize("", off) -#endif // LL_MSVC - -LLCoros::CoroData::CoroData(CoroData* prev, const std::string& name, - const callable_t& callable, S32 stacksize): - mPrev(prev), +LLCoros::CoroData::CoroData(const std::string& name): mName(name), - // Wrap the caller's callable in our toplevel() function so we can manage - // Current appropriately at startup and shutdown of each coroutine. - mCoro(boost::bind(toplevel, _1, this, callable), stacksize), // don't consume events unless specifically directed mConsuming(false), - mSelf(0), mCreationTime(LLTimer::getTotalSeconds()) { } -std::string LLCoros::launch(const std::string& prefix, const callable_t& callable) +void LLCoros::delete_CoroData(CoroData* cdptr) { - std::string name(generateDistinctName(prefix)); - Current current; - // pass the current value of Current as previous context - CoroData* newCoro = new(std::nothrow) CoroData(current, name, callable, mStackSize); - if (newCoro == NULL) + // This custom cleanup function is necessarily static. Find and bind the + // LLCoros instance. + LLCoros& self(LLCoros::instance()); + // We set mCurrent on entry to a new fiber, expecting that the + // corresponding entry has already been stored in mCoros. It is an + // error if we do not find that entry. + CoroMap::iterator found = self.mCoros.find(cdptr->mName); + if (found == self.mCoros.end()) { - // Out of memory? - printActiveCoroutines(); - LL_ERRS("LLCoros") << "Failed to start coroutine: " << name << " Stacksize: " << mStackSize << " Total coroutines: " << mCoros.size() << LL_ENDL; + LL_ERRS("LLCoros") << "Coroutine '" << cdptr->mName << "' terminated " + << "without being stored in LLCoros::mCoros" + << LL_ENDL; } - // Store it in our pointer map - mCoros.insert(name, newCoro); - // also set it as current - current.reset(newCoro); - /* Run the coroutine until its first wait, then return here */ - (newCoro->mCoro)(std::nothrow); - return name; -} -#if LL_MSVC -// reenable optimizations -#pragma optimize("", on) -#endif // LL_MSVC + // Oh good, we found the mCoros entry. Erase it. Because it's a ptr_map, + // that will implicitly delete this CoroData. + self.mCoros.erase(found); +} |