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Commit ffad7d1f authored by Dianne Hackborn's avatar Dianne Hackborn
Browse files

Add new Looper API to check whether the looper is idle. 

This is just to support the watchdog to give it a faster
way to determine if a thread is deadlocked without having
to post a message to it.

Change-Id: I068dc8b9387caf94fe5811fb4aeb0f9b57b1a080
parent 77943437

include/utils/Looper.h

+11 −0
Original line number Diff line number Diff line
@@ -296,6 +296,13 @@ public: 
     */

    void removeMessages(const sp<MessageHandler>& handler, int what);



    /**

     * Return whether this looper's thread is currently idling -- that is, whether it

     * stopped waiting for more work to do.  Note that this is intrinsically racy, since

     * its state can change before you get the result back.

     */

    bool isIdling() const;



    /**

     * Prepares a looper associated with the calling thread, and returns it.

     * If the thread already has a looper, it is returned.  Otherwise, a new
@@ -353,6 +360,10 @@ private: 
    Vector<MessageEnvelope> mMessageEnvelopes; // guarded by mLock

    bool mSendingMessage; // guarded by mLock



    // Whether we are currently waiting for work.  Not protected by a lock,

    // any use of it is racy anyway.

    volatile bool mIdling;



    int mEpollFd; // immutable



    // Locked list of file descriptor monitoring requests.

libs/utils/Looper.cpp

+12 −0
Original line number Diff line number Diff line
@@ -84,6 +84,8 @@ Looper::Looper(bool allowNonCallbacks) : 
    LOG_ALWAYS_FATAL_IF(result != 0, "Could not make wake write pipe non-blocking.  errno=%d",

            errno);



    mIdling = false;



    // Allocate the epoll instance and register the wake pipe.

    mEpollFd = epoll_create(EPOLL_SIZE_HINT);

    LOG_ALWAYS_FATAL_IF(mEpollFd < 0, "Could not create epoll instance.  errno=%d", errno);
@@ -214,9 +216,15 @@ int Looper::pollInner(int timeoutMillis) { 
    mResponses.clear();

    mResponseIndex = 0;



    // We are about to idle.

    mIdling = true;



    struct epoll_event eventItems[EPOLL_MAX_EVENTS];

    int eventCount = epoll_wait(mEpollFd, eventItems, EPOLL_MAX_EVENTS, timeoutMillis);



    // No longer idling.

    mIdling = false;



    // Acquire lock.

    mLock.lock();
@@ -558,4 +566,8 @@ void Looper::removeMessages(const sp<MessageHandler>& handler, int what) { 
    } // release lock

}



bool Looper::isIdling() const {

    return mIdling;

}



} // namespace android