问JIT去优化，reason=“约束”。为什么JIT去优化方法？

EN

@SynchronizationRequired
public class Worker implements Runnable
{
    private static final byte NOT_RUNNING = 0, RUNNING = 1, SHUTDOWN = 2, FORCE_SHUTDOWN = 3;
    private static final AtomicIntegerFieldUpdater<Worker> isRunningFieldUpdater =
            AtomicIntegerFieldUpdater.newUpdater(Worker.class, "isRunning");

    private volatile int isRunning = NOT_RUNNING;

    private final Queue<FunkovConnection> tasks = new SpscUnboundedArrayQueue<>(512);

    /**
     * Executing tasks from queue until closed.
     */
    @Override
    public void run()
    {
        if (isRunning())
        {
            return;
        }

        while (notClosed())
        {
            FunkovConnection connection = tasks.poll();
            if (null != connection)
            {
                connection.run();
            }
        }

        if (forceShutdown())
        {
            setNonRunning();
            return;
        }

        FunkovConnection connection;
        while ((connection = tasks.poll()) != null)
        {
            connection.run();
        }

        setNonRunning();
    }

    public void submit(FunkovConnection connection)
    {
        tasks.add(connection);
    }


    /**
     * Shutdowns worker after it finish processing all pending tasks on its queue
     */
    public void shutdown()
    {
        isRunningFieldUpdater.compareAndSet(this, RUNNING, SHUTDOWN);
    }

    /**
     * Shutdowns worker after it finish currently processing task. Pending tasks on queue are not handled
     */
    public void shutdownForce()
    {
        isRunningFieldUpdater.compareAndSet(this, RUNNING, FORCE_SHUTDOWN);
    }

    private void setNonRunning()
    {
        isRunningFieldUpdater.set(this, NOT_RUNNING);
    }

    private boolean forceShutdown()
    {
        return isRunningFieldUpdater.get(this) == FORCE_SHUTDOWN;
    }

    private boolean isRunning()
    {
        return isRunningFieldUpdater.getAndSet(this, RUNNING) == RUNNING;
    }

    public boolean notClosed()
    {
        return isRunningFieldUpdater.get(this) == RUNNING;
    }
}

 1. <task_queued compile_id='535' compile_kind='osr' method='Worker run ()V' bytes='81' count='1' backedge_count='60416' iicount='1' osr_bci='8' level='3' stamp='0,145' comment='tiered' hot_count='60416'/>
 2. <nmethod compile_id='535' compile_kind='osr' compiler='c1' level='3' entry='0x00007fabf5514ee0' size='5592' address='0x00007fabf5514c10' relocation_offset='344' insts_offset='720' stub_offset='4432' scopes_data_offset='4704' scopes_pcs_offset='5040' dependencies_offset='5552' nul_chk_table_offset='5560' oops_offset='4624' metadata_offset='4640' method='Worker run ()V' bytes='81' count='1' backedge_count='65742' iicount='1' stamp='0,146'/>
 3. <deoptimized thread='132773' reason='constraint' pc='0x00007fabf5515c24' compile_id='535' compile_kind='osr' compiler='c1' level='3'>
<jvms bci='37' method='Worker run ()V' bytes='81' count='1' backedge_count='68801' iicount='1'/>
</deoptimized>
4. <deoptimized thread='132773' reason='constraint' pc='0x00007fabf5515c24' compile_id='535' compile_kind='osr' compiler='c1' level='3'>
<jvms bci='37' method='Worker run ()V' bytes='81' count='1' backedge_count='76993' iicount='1'/>
</deoptimized>
5.<deoptimized thread='132773' reason='constraint' pc='0x00007fabf5515c24' compile_id='535' compile_kind='osr' compiler='c1' level='3'>
<jvms bci='37' method='Worker run ()V' bytes='81' count='1' backedge_count='85185' iicount='1'/>
</deoptimized>
6. <deoptimized thread='132773' reason='constraint' pc='0x00007fabf5515c24' compile_id='535' compile_kind='osr' compiler='c1' level='3'>
<jvms bci='37' method='Worker run ()V' bytes='81' count='1' backedge_count='93377' iicount='1'/>
</deoptimized>