From 1cadeb40df15c1eaef3410064f9a2b8e4489082d Mon Sep 17 00:00:00 2001
From: Nat Goodspeed <nat@lindenlab.com>
Date: Tue, 6 Sep 2016 21:25:57 -0400
Subject: [PATCH] MAINT-5232: Prevent runaway LLSingletonBase::MasterList
growth.
Until we reimplement LLCoros on Boost.Fiber, we must hand-implement
coroutine-local data. That presently takes the form of a map keyed on
llcoro::id, whose values are the stacks of currently-initializing LLSingleton
instances.
But since the viewer launches an open-ended number of coroutines, we could end
up with an open-ended number of map entries unless we intentionally prune the
map. So every time we pop the stack to empty, remove that map entry.
This could result in thrashing, a given coroutine's 'initializing' stack being
created and deleted for almost every LLSingleton instantiated by that
coroutine -- but the number of different LLSingletons is necessarily static,
and the lifespan of each is the entire rest of the process. Even a couple
dozen LLSingletons won't thrash that badly.
---
indra/llcommon/llsingleton.cpp | 22 +++++++++++++++++++++-
1 file changed, 21 insertions(+), 1 deletion(-)
diff --git a/indra/llcommon/llsingleton.cpp b/indra/llcommon/llsingleton.cpp
index 3f65820f2ed..24ccc8ddb42 100644
--- a/indra/llcommon/llsingleton.cpp
+++ b/indra/llcommon/llsingleton.cpp
@@ -94,6 +94,15 @@ class LLSingletonBase::MasterList:
// here. It returns a reference to the selected mapped_type instance.
return mInitializing[llcoro::get_id()];
}
+
+ void cleanup_initializing_()
+ {
+ InitializingMap::iterator found = mInitializing.find(llcoro::get_id());
+ if (found != mInitializing.end())
+ {
+ mInitializing.erase(found);
+ }
+ }
};
//static
@@ -129,7 +138,7 @@ LLSingletonBase::list_t& LLSingletonBase::get_initializing()
//static
LLSingletonBase::list_t& LLSingletonBase::get_initializing_from(MasterList* master)
{
- return master->get_initializing_();;
+ return master->get_initializing_();
}
LLSingletonBase::~LLSingletonBase() {}
@@ -156,6 +165,17 @@ void LLSingletonBase::pop_initializing()
// and pop it
list.pop_back();
+ // The viewer launches an open-ended number of coroutines. While we don't
+ // expect most of them to initialize LLSingleton instances, our present
+ // get_initializing() logic could lead to an open-ended number of map
+ // entries. So every time we pop the stack back to empty, delete the entry
+ // entirely.
+ if (list.empty())
+ {
+ MasterList::instance().cleanup_initializing_();
+ }
+
+ // Now validate the newly-popped LLSingleton.
if (back != this)
{
logerrs("Push/pop mismatch in stack of currently-initializing LLSingletons: ",
--
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