int32
runtime·semasleep(int64 ns)
{
Timespec ts;
int64 secs;
// spin-mutex lock
while(runtime·xchg(&m->waitsemalock, 1))
runtime·osyield();
for(;;) {
// lock held
if(m->waitsemacount == 0) {
// sleep until semaphore != 0 or timeout.
// thrsleep unlocks m->waitsemalock.
if(ns < 0)
runtime·thrsleep(&m->waitsemacount, 0, nil, &m->waitsemalock, nil);
else {
ns += runtime·nanotime();
secs = ns/1000000000LL;
// Avoid overflow
if(secs >= 1LL<<31)
secs = (1LL<<31) - 1;
ts.tv_sec = secs;
ts.tv_nsec = ns%1000000000LL;
runtime·thrsleep(&m->waitsemacount, CLOCK_REALTIME, &ts, &m->waitsemalock, nil);
}
// reacquire lock
while(runtime·xchg(&m->waitsemalock, 1))
runtime·osyield();
}
// lock held (again)
if(m->waitsemacount != 0) {
// semaphore is available.
m->waitsemacount--;
// spin-mutex unlock
runtime·atomicstore(&m->waitsemalock, 0);
return 0; // semaphore acquired
}
// semaphore not available.
// if there is a timeout, stop now.
// otherwise keep trying.
if(ns >= 0)
break;
}
// lock held but giving up
// spin-mutex unlock
runtime·atomicstore(&m->waitsemalock, 0);
return -1;
}
int32
runtime·semasleep(int64 ns)
{
Timespec ts;
// spin-mutex lock
while(runtime·xchg(&m->waitsemalock, 1))
runtime·osyield();
for(;;) {
// lock held
if(m->waitsemacount == 0) {
// sleep until semaphore != 0 or timeout.
// thrsleep unlocks m->waitsemalock.
if(ns < 0)
runtime·thrsleep(&m->waitsemacount, 0, nil, &m->waitsemalock, nil);
else {
ns += runtime·nanotime();
// NOTE: tv_nsec is int64 on amd64, so this assumes a little-endian system.
ts.tv_nsec = 0;
ts.tv_sec = runtime·timediv(ns, 1000000000, (int32*)&ts.tv_nsec);
runtime·thrsleep(&m->waitsemacount, CLOCK_MONOTONIC, &ts, &m->waitsemalock, nil);
}
// reacquire lock
while(runtime·xchg(&m->waitsemalock, 1))
runtime·osyield();
}
// lock held (again)
if(m->waitsemacount != 0) {
// semaphore is available.
m->waitsemacount--;
// spin-mutex unlock
runtime·atomicstore(&m->waitsemalock, 0);
return 0; // semaphore acquired
}
// semaphore not available.
// if there is a timeout, stop now.
// otherwise keep trying.
if(ns >= 0)
break;
}
// lock held but giving up
// spin-mutex unlock
runtime·atomicstore(&m->waitsemalock, 0);
return -1;
}
// Free n objects from a span s back into the central free list c.
// Called during sweep.
// Returns true if the span was returned to heap. Sets sweepgen to
// the latest generation.
bool
runtime·MCentral_FreeSpan(MCentral *c, MSpan *s, int32 n, MLink *start, MLink *end)
{
if(s->incache)
runtime·throw("freespan into cached span");
runtime·lock(c);
// Move to nonempty if necessary.
if(s->freelist == nil) {
runtime·MSpanList_Remove(s);
runtime·MSpanList_Insert(&c->nonempty, s);
}
// Add the objects back to s's free list.
end->next = s->freelist;
s->freelist = start;
s->ref -= n;
c->nfree += n;
// delay updating sweepgen until here. This is the signal that
// the span may be used in an MCache, so it must come after the
// linked list operations above (actually, just after the
// lock of c above.)
runtime·atomicstore(&s->sweepgen, runtime·mheap.sweepgen);
if(s->ref != 0) {
runtime·unlock(c);
return false;
}
// s is completely freed, return it to the heap.
MCentral_ReturnToHeap(c, s); // unlocks c
return true;
}
void
runtime·resetcpuprofiler(int32 hz)
{
static Lock lock;
void *timer, *thread;
int32 ms;
int64 due;
runtime·lock(&lock);
if(profiletimer == nil) {
timer = runtime·stdcall(runtime·CreateWaitableTimer, 3, nil, nil, nil);
runtime·atomicstorep(&profiletimer, timer);
thread = runtime·stdcall(runtime·CreateThread, 6,
nil, nil, runtime·profileloop, nil, nil, nil);
runtime·stdcall(runtime·CloseHandle, 1, thread);
}
runtime·unlock(&lock);
ms = 0;
due = 1LL<<63;
if(hz > 0) {
ms = 1000 / hz;
if(ms == 0)
ms = 1;
due = ms * -10000;
}
runtime·stdcall(runtime·SetWaitableTimer, 6,
profiletimer, &due, (uintptr)ms, nil, nil, nil);
runtime·atomicstore((uint32*)&m->profilehz, hz);
}
runtime·findfunc(uintptr addr)
{
Func *f;
int32 nf, n;
// Use atomic double-checked locking,
// because when called from pprof signal
// handler, findfunc must run without
// grabbing any locks.
// (Before enabling the signal handler,
// SetCPUProfileRate calls findfunc to trigger
// the initialization outside the handler.)
// Avoid deadlock on fault during malloc
// by not calling buildfuncs if we're already in malloc.
if(!m->mallocing && !m->gcing) {
if(runtime·atomicload(&funcinit) == 0) {
runtime·lock(&funclock);
if(funcinit == 0) {
buildfuncs();
runtime·atomicstore(&funcinit, 1);
}
runtime·unlock(&funclock);
}
}
if(nfunc == 0)
return nil;
if(addr < func[0].entry || addr >= func[nfunc].entry)
return nil;
// binary search to find func with entry <= addr.
f = func;
nf = nfunc;
while(nf > 0) {
n = nf/2;
if(f[n].entry <= addr && addr < f[n+1].entry)
return &f[n];
else if(addr < f[n].entry)
nf = n;
else {
f += n+1;
nf -= n+1;
}
}
// can't get here -- we already checked above
// that the address was in the table bounds.
// this can only happen if the table isn't sorted
// by address or if the binary search above is buggy.
runtime·prints("findfunc unreachable\n");
return nil;
}
void
runtime·semawakeup(M *mp)
{
uint32 ret;
// spin-mutex lock
while(runtime·xchg(&mp->waitsemalock, 1))
runtime·osyield();
mp->waitsemacount++;
ret = runtime·thrwakeup(&mp->waitsemacount, 1);
if(ret != 0 && ret != ESRCH)
runtime·printf("thrwakeup addr=%p sem=%d ret=%d\n", &mp->waitsemacount, mp->waitsemacount, ret);
// spin-mutex unlock
runtime·atomicstore(&mp->waitsemalock, 0);
}
void
runtime·semawakeup(M *mp)
{
uint32 ret;
// spin-mutex lock
while(runtime·xchg(&mp->waitsemalock, 1))
runtime·osyield();
mp->waitsemacount++;
// TODO(jsing) - potential deadlock, see semasleep() for details.
// Confirm that LWP is parked before unparking...
ret = runtime·lwp_unpark(mp->procid, &mp->waitsemacount);
if(ret != 0 && ret != ESRCH)
runtime·printf("thrwakeup addr=%p sem=%d ret=%d\n", &mp->waitsemacount, mp->waitsemacount, ret);
// spin-mutex unlock
runtime·atomicstore(&mp->waitsemalock, 0);
}
// Allocate a new span of npage pages from the heap for GC'd memory
// and record its size class in the HeapMap and HeapMapCache.
static MSpan*
mheap_alloc(MHeap *h, uintptr npage, int32 sizeclass, bool large)
{
MSpan *s;
if(g != g->m->g0)
runtime·throw("mheap_alloc not on M stack");
runtime·lock(&h->lock);
// To prevent excessive heap growth, before allocating n pages
// we need to sweep and reclaim at least n pages.
if(!h->sweepdone)
MHeap_Reclaim(h, npage);
// transfer stats from cache to global
mstats.heap_alloc += g->m->mcache->local_cachealloc;
g->m->mcache->local_cachealloc = 0;
s = MHeap_AllocSpanLocked(h, npage);
if(s != nil) {
// Record span info, because gc needs to be
// able to map interior pointer to containing span.
runtime·atomicstore(&s->sweepgen, h->sweepgen);
s->state = MSpanInUse;
s->freelist = nil;
s->ref = 0;
s->sizeclass = sizeclass;
s->elemsize = (sizeclass==0 ? s->npages<<PageShift : runtime·class_to_size[sizeclass]);
// update stats, sweep lists
if(large) {
mstats.heap_objects++;
mstats.heap_alloc += npage<<PageShift;
// Swept spans are at the end of lists.
if(s->npages < nelem(h->free))
runtime·MSpanList_InsertBack(&h->busy[s->npages], s);
else
runtime·MSpanList_InsertBack(&h->busylarge, s);
}
}
runtime·unlock(&h->lock);
return s;
}
int32
runtime·semasleep(int64 ns)
{
Timespec ts;
// spin-mutex lock
while(runtime·xchg(&m->waitsemalock, 1))
runtime·osyield();
for(;;) {
// lock held
if(m->waitsemacount == 0) {
// sleep until semaphore != 0 or timeout.
// thrsleep unlocks m->waitsemalock.
if(ns < 0) {
// TODO(jsing) - potential deadlock!
//
// There is a potential deadlock here since we
// have to release the waitsemalock mutex
// before we call lwp_park() to suspend the
// thread. This allows another thread to
// release the lock and call lwp_unpark()
// before the thread is actually suspended.
// If this occurs the current thread will end
// up sleeping indefinitely. Unfortunately
// the NetBSD kernel does not appear to provide
// a mechanism for unlocking the userspace
// mutex once the thread is actually parked.
runtime·atomicstore(&m->waitsemalock, 0);
runtime·lwp_park(nil, 0, &m->waitsemacount, nil);
} else {
ns += runtime·nanotime();
ts.tv_sec = ns/1000000000LL;
ts.tv_nsec = ns%1000000000LL;
// TODO(jsing) - potential deadlock!
// See above for details.
runtime·atomicstore(&m->waitsemalock, 0);
runtime·lwp_park(&ts, 0, &m->waitsemacount, nil);
}
// reacquire lock
while(runtime·xchg(&m->waitsemalock, 1))
runtime·osyield();
}
// lock held (again)
if(m->waitsemacount != 0) {
// semaphore is available.
m->waitsemacount--;
// spin-mutex unlock
runtime·atomicstore(&m->waitsemalock, 0);
return 0; // semaphore acquired
}
// semaphore not available.
// if there is a timeout, stop now.
// otherwise keep trying.
if(ns >= 0)
break;
}
// lock held but giving up
// spin-mutex unlock
runtime·atomicstore(&m->waitsemalock, 0);
return -1;
}
