__attribute_cold__
__attribute_noinline__
static int
plasma_spin_nprocs_init (void)
{
long nprocs_onln = plasma_sysconf_nprocessors_onln();
uint32_t nshift_onln;
uint32_t nshift_accum = 0;
if (nprocs_onln < 1)
nprocs_onln = 1;
nshift_onln = (uint32_t)nprocs_onln;
while ((nshift_onln >>= 1))
++nshift_accum;
nshift = nshift_accum; /* power of 2 of available CPUs (0 if only 1 CPU) */
plasma_membar_StoreStore();
return (nprocs = (uint32_t)nprocs_onln);
/* store ordering above is not critical; so our readers below do not acquire
* If there is a race between threads before nprocs is set, then if a thread
* reads nshift = 0, but nprocs != 0, then thread might be slightly slower
* acquiring the spin lock the first time. Not a big deal. Likewise, it
* is not problem if multiple threads run this routine since this routine
* stores results atomically (via int-sized natural alignment) to the
* static variables and the results of initialization are the same. */
}
__attribute_noinline__
static bool
_nss_mcdb_db_openshared(const enum nss_dbtype dbtype)
{
#ifdef _THREAD_SAFE
static pthread_mutex_t _nss_mcdb_global_mutex = PTHREAD_MUTEX_INITIALIZER;
#endif
struct mcdb_mmap * const restrict map = &_nss_mcdb_mmap_st[dbtype];
bool rc;
if (pthread_mutex_lock(&_nss_mcdb_global_mutex) != 0)
return false;
if (__builtin_expect( _nss_mcdb_mmap[dbtype] != 0, false)) {
/* init'ed by another thread while waiting for mutex */
pthread_mutex_unlock(&_nss_mcdb_global_mutex);
return true;
}
#ifdef _FORTIFY_SOURCE
{ static bool atexit_once = true;
if (atexit_once) {
atexit_once = false;
atexit(_nss_mcdb_atexit);
}
}
#endif
/* pass full path in fname instead of separate dirname and basename
* (not using openat(), fstatat() where someone might close dfd on us)
* use static storage for initial struct mcdb_mmap for each dbtype
* to avoid malloc allocation in short-lived programs, and to maintain
* a reference to maps to keep them available. */
if ((rc = (NULL != mcdb_mmap_create_h(map, NULL, _nss_dbnames[dbtype],
malloc, free)))) {
plasma_membar_StoreStore();
_nss_mcdb_mmap[dbtype] = map;
}
pthread_mutex_unlock(&_nss_mcdb_global_mutex);
return rc;
}
