package time import ( "strings" "unsafe" "fmt" "gvisor.dev/gvisor/pkg/syncutil" "reflect" ) // SeqAtomicLoad returns a copy of *ptr, ensuring that the read does not race // with any writer critical sections in sc. func SeqAtomicLoadParameters(sc *syncutil.SeqCount, ptr *Parameters) Parameters { // This function doesn't use SeqAtomicTryLoad because doing so is // measurably, significantly (~20%) slower; Go is awful at inlining. var val Parameters for { epoch := sc.BeginRead() if syncutil.RaceEnabled { syncutil.Memmove(unsafe.Pointer(&val), unsafe.Pointer(ptr), unsafe.Sizeof(val)) } else { val = *ptr } if sc.ReadOk(epoch) { break } } return val } // SeqAtomicTryLoad returns a copy of *ptr while in a reader critical section // in sc initiated by a call to sc.BeginRead() that returned epoch. If the read // would race with a writer critical section, SeqAtomicTryLoad returns // (unspecified, false). func SeqAtomicTryLoadParameters(sc *syncutil.SeqCount, epoch syncutil.SeqCountEpoch, ptr *Parameters) (Parameters, bool) { var val Parameters if syncutil.RaceEnabled { syncutil.Memmove(unsafe.Pointer(&val), unsafe.Pointer(ptr), unsafe.Sizeof(val)) } else { val = *ptr } return val, sc.ReadOk(epoch) } func initParameters() { var val Parameters typ := reflect.TypeOf(val) name := typ.Name() if ptrs := syncutil.PointersInType(typ, name); len(ptrs) != 0 { panic(fmt.Sprintf("SeqAtomicLoad<%s> is invalid since values %s of type %s contain pointers:\n%s", typ, name, typ, strings.Join(ptrs, "\n"))) } }