os::create_attached_thread(JavaThread* thread)

openjdk7-hotspot os.hpp
  • 引数で渡されたJavaスレッドをOSスレッドに結びつける
//Linux版(jdk7/hotspot/src/os/linux/vm/os_linux.cpp)
Bool os::create_attached_thread(JavaThread* thread) {
#Ifdef ASSERT
    thread->verify_not_published();
#endif

  // Allocate the OSThread object
  OSThread* osthread = new OSThread(NULL, NULL);

  if (osthread == NULL) {
    return false;
  }

  // Store pthread info into the OSThread
  osthread->set_thread_id(os::Linux::gettid());
  osthread->set_pthread_id(::pthread_self());

  // initialize floating point control register
  os::Linux::init_thread_fpu_state();

  // Initial thread state is RUNNABLE
  osthread->set_state(RUNNABLE);

  thread->set_osthread(osthread);

  if (UseNUMA) {
    int lgrp_id = os::numa_get_group_id();
    if (lgrp_id != -1) {
      thread->set_lgrp_id(lgrp_id);
    }
  }

  if (os::Linux::is_initial_thread()) {
    // If current thread is initial thread, its stack is mapped on demand,
    // see notes about MAP_GROWSDOWN. Here we try to force kernel to map
    // the entire stack region to avoid SEGV in stack banging.
    // It is also useful to get around the heap-stack-gap problem on SuSE
    // kernel (see 4821821 for details). We first expand stack to the top
    // of yellow zone, then enable stack yellow zone (order is significant,
    // enabling yellow zone first will crash JVM on SuSE Linux), so there
    // is no gap between the last two virtual memory regions.

    JavaThread *jt = (JavaThread *)thread;
    address addr = jt->stack_yellow_zone_base();
    assert(addr != NULL, "initialization problem?");
    assert(jt->stack_available(addr) > 0, "stack guard should not be enabled");

    osthread->set_expanding_stack();
    os::Linux::manually_expand_stack(jt, addr);
    osthread->clear_expanding_stack();
  }

  // initialize signal mask for this thread
  // and save the caller's signal mask
  os::Linux::hotspot_sigmask(thread);

  return true;
}