riscv
/
musl
mirror of https://git.musl-libc.org/git/musl
1
0
Fork 0
Code Issues Projects Releases Wiki Activity
Browse Source

in pthread_mutex_timedlock, avoid repeatedly reading mutex type field 

compiler cannot cache immutable fields of the mutex object across
external calls it can't see, much less across atomics.
master
Rich Felker 8 years ago
parent
4e4a162d9a
commit
d1fa288606
1 changed files with 4 additions and 3 deletions
Whitespace
Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL
Unified View
Diff Options
Show Stats Download Patch File Download Diff File
  1. 7
      src/thread/pthread_mutex_timedlock.c

7
src/thread/pthread_mutex_timedlock.c
View File

@ -6,7 +6,8 @@ int __pthread_mutex_timedlock(pthread_mutex_t *restrict m, const struct timespec
&& !a_cas(&m->_m_lock, 0, EBUSY)) && !a_cas(&m->_m_lock, 0, EBUSY))
return 0; return 0;
int r, t, priv = (m->_m_type & 128) ^ 128; int type = m->_m_type;
int r, t, priv = (type & 128) ^ 128;
r = pthread_mutex_trylock(m); r = pthread_mutex_trylock(m);
if (r != EBUSY) return r; if (r != EBUSY) return r;
@ -15,9 +16,9 @@ int __pthread_mutex_timedlock(pthread_mutex_t *restrict m, const struct timespec
while (spins-- && m->_m_lock && !m->_m_waiters) a_spin(); while (spins-- && m->_m_lock && !m->_m_waiters) a_spin();
while ((r=pthread_mutex_trylock(m)) == EBUSY) { while ((r=pthread_mutex_trylock(m)) == EBUSY) {
if (!(r=m->_m_lock) || ((r&0x40000000) && (m->_m_type&4))) if (!(r=m->_m_lock) || ((r&0x40000000) && (type&4)))
continue; continue;
if ((m->_m_type&3) == PTHREAD_MUTEX_ERRORCHECK if ((type&3) == PTHREAD_MUTEX_ERRORCHECK
&& (r&0x7fffffff) == __pthread_self()->tid) && (r&0x7fffffff) == __pthread_self()->tid)
return EDEADLK; return EDEADLK;

Write Preview
Loading…
Cancel
Save