@@ -231,10 +231,14 @@ function spawn_or_use_existing(app_root): count++ active++ else: - # There are no apps for this app root. - wait until - (active < max) and - (max_per_app == 0 or app_instance_count[app_root] < max_per_app) + # There are no apps for this app root. Wait until there's at + # least 1 idle instance, or until there's an empty slot in the + # pool, then restart this function. Restarting is necessary, + # because after waiting and reacquiring the lack, some other + # thread might already have spawned instances for this app root. + if (active >= max): + wait until _active_ has changed + goto beginning of function # FIXME: there's a possible concurrency issue here. After # waiting and having reacquired the lock, the state might have # been completely changed, and there may now exist an instance doc/ApplicationPool algorithm.txt @@ -449,11 +449,9 @@ private: activeOrMaxChanged.notify_all(); } } else { - while (!( - active < max && - (maxPerApp == 0 || appInstanceCount[appRoot] < maxPerApp) - )) { + if (active >= max) { activeOrMaxChanged.wait(l); + goto beginning_of_function; } if (count == max) { container = inactiveApps.front(); @@ -654,6 +652,7 @@ public: appInstanceCount.clear(); count = 0; active = 0; + activeOrMaxChanged.notify_all(); } virtual void setMaxIdleTime(unsigned int seconds) { ext/apache2/StandardApplicationPool.h 375f188a0410ef392f853fc6855b08d87f03d513 Hongli Lai (Phusion) hongli@phusion.nl http://github.com/FooBarWidget/passenger/commit/1ad9d7930b4a91895c550579306f2369495e78b3 1ad9d7930b4a91895c550579306f2369495e78b3 2008-12-05T02:10:33-08:00 2008-12-05T02:10:33-08:00 Backport an ApplicationPool race condition and invariant violation fix. Some people reported that 'count' can go over 'max'. This is the cause, I suspect. 234662eb6a489f368d2c12cf1cd5521023141a15 Hongli Lai (Phusion) hongli@phusion.nl