commit 47431c12bc54ff9717f15228767d0f6d469fc786
author Elie Kheirallah <khei@google.com> Thu Apr 21 23:46:17 2022 +0000
committer Elie Kheirallah <khei@google.com> Thu May 19 16:00:31 2022 +0000
tree 012eaacdea3e325d1f8802afbfbfb002485548a5
parent 7863bb5118f2289d59c205f621bb437a66740c4f

Tracking number of threads in threadpools.
Added tests for max total thread count.

Renamed getThreadPoolMaxThreadCount to getThreadPoolMaxTotalThreadCount
which takes into account user joined threads and polling threads.
Test added to check that the current available threads update properly
and do not lock.
Added second test that simulates a deadlock and confirms the deadlock.

Bug: 188834514
Test: binderLibTest
Change-Id: Ia99d95544a38596ec9fc316e623e523b64337bc7

libs/binder/IPCThreadState.cpp

diff --git a/libs/binder/IPCThreadState.cpp b/libs/binder/IPCThreadState.cpp
index d453ac7..d536219 100644
--- a/libs/binder/IPCThreadState.cpp
+++ b/libs/binder/IPCThreadState.cpp
@@ -638,7 +638,9 @@
 void IPCThreadState::joinThreadPool(bool isMain)
 {
     LOG_THREADPOOL("**** THREAD %p (PID %d) IS JOINING THE THREAD POOL\n", (void*)pthread_self(), getpid());
-
+    pthread_mutex_lock(&mProcess->mThreadCountLock);
+    mProcess->mCurrentThreads++;
+    pthread_mutex_unlock(&mProcess->mThreadCountLock);
     mOut.writeInt32(isMain ? BC_ENTER_LOOPER : BC_REGISTER_LOOPER);
 
     mIsLooper = true;
@@ -666,6 +668,13 @@
     mOut.writeInt32(BC_EXIT_LOOPER);
     mIsLooper = false;
     talkWithDriver(false);
+    pthread_mutex_lock(&mProcess->mThreadCountLock);
+    LOG_ALWAYS_FATAL_IF(mProcess->mCurrentThreads == 0,
+                        "Threadpool thread count = 0. Thread cannot exist and exit in empty "
+                        "threadpool\n"
+                        "Misconfiguration. Increase threadpool max threads configuration\n");
+    mProcess->mCurrentThreads--;
+    pthread_mutex_unlock(&mProcess->mThreadCountLock);
 }
 
 status_t IPCThreadState::setupPolling(int* fd)
@@ -677,6 +686,9 @@
     mOut.writeInt32(BC_ENTER_LOOPER);
     flushCommands();
     *fd = mProcess->mDriverFD;
+    pthread_mutex_lock(&mProcess->mThreadCountLock);
+    mProcess->mCurrentThreads++;
+    pthread_mutex_unlock(&mProcess->mThreadCountLock);
     return 0;
 }