// bitmap stores the pointer/scalar bitmap for the words in // this arena. See mbitmap.go for a description. Use the // heapBits type to access this. bitmap [heapArenaBitmapBytes]byte //arenas is the heap arena
x = unsafe.Pointer(c.tiny + off) c.tinyoffset = off + size c.local_tinyallocs++ releasem(mp) return x } ... } ... } ... } 当内存块中不包含空闲的内存时,下面的这段代码会先从线程缓存找到跨度类对应的内存管理单元runtime.mspan,调用runtime.nextFreeFast获取空闲的内存;当不存在空闲内存...
or// nil if there is no current tiny block./// tiny is a heap pointer. Since mcache is in non-GC'd memory,// we handle it by clearing it in releaseAll during mark// termination.///
// Not enough room in the current arena. Allocate more // arena space. This may not be contiguous with the // current arena, so we have to request the full ask. av, asize := h.sysAlloc(ask) if av == nil { print("runtime: out of memory: cannot allocate ", ask, "-byte blo...
The new build-in functionallocates memory(仅仅分配空间). The first argument is a type, not a value, and the value returned is a pointer to a newly allocated zero value of that type.内置函数new分配空间。传递给new函数的是一个类型,不是一个值。返回值是 指向这个新分配的零值的指针。
{...// Allocator cache for tiny objects w/o pointers.// See "Tiny allocator" comment in malloc.go.// tiny points to the beginning of the current tiny block, or// nil if there is no current tiny block./// tiny is a heap pointer. Since mcache is in non-GC'd memory,// we hand...
funcDijkstraWritePointer(slot*unsafe.Pointer,ptr unsafe.Pointer)shade(ptr)//先将新下游对象 ptr 标记为灰色 *slot = ptr}//说明:添加下游对象(当前下游对象slot, 新下游对象ptr) { //step 1 标记灰色(新下游对象ptr) //step 2 当前下游对象slot = 新下游对象ptr }//场景:A.添加下游对象(nil, B) /...
// growslice allocates new backing store for a slice./// arguments:/// oldPtr = pointer to the slice's backing array// newLen = new length (= oldLen + num)// oldCap = original slice's capacity.// num = number of elements being added// et = element type/// return ...
使用span机制来减少内存碎片,每个span至少为一个页(go中的一个page为8KB),且大小为页的整数倍,每一种span用于一个范围的内存分配需求. 比如16-32byte使用...
// the garbage collector could follow a pointer to x, // but see uninitialized memory or stale heap bits. publicationBarrier() // 如果当前在GC中, 需要立刻标记分配后的对象为"黑色", 防止它被回收 // Allocate black during GC. // All slots hold nil so no scanning is needed. ...