On Wednesday, 22 March 2017 19:29:02 UTC+11, T L wrote: > > > > On Wednesday, March 22, 2017 at 4:08:02 PM UTC+8, Dave Cheney wrote: >> >> >> >> On Wednesday, 22 March 2017 19:04:36 UTC+11, T L wrote: >>> >>> In this article: https://blog.golang.org/go15gc , it mentions >>> >>> ..., The GC visits all *roots*, which are objects directly accessible >>>> by the application such as globals and things on the stack, and colors >>>> these grey. ... >>> >>> >>> It lists two kinds of root objects: globals and objects on stacks. >>> My question is how objects on heap will be visited? >>> >> >> By walking the heap (there are some optimisations to avoid areas of >> memory where no objects are known to be stored) >> > > Walking the heap is at collecting stage? Will the heap be walked at > analyzing stage? >
Garbage collection has two main phases; mark and sweep. The heap is walked during the marking phase. > > >> >> >>> For every object on heap, is it always been referenced by another global >>> object or another object on a stack? >>> >> >> Yes, otherwise it's garbage :) >> > > So when a memory block for a local object is allocated on heap, there will > be also a pointer, which stores the address of the memory block, recorded > on stack? > When memory is allocated on the heap, memory is allocated on the heap; that's it. The garbage collector records the details of the type of the allocation in the heap alongside the object for most* allocations. * for small allocations they go into their own areas; google slab allocator. So that the memory block on heap will be tracked from stack? > >From any gc root. The point is if there is no path from a gc root to an area of memory on the heap, that area is unreachable and therefore can be reused. > > -- You received this message because you are subscribed to the Google Groups "golang-nuts" group. To unsubscribe from this group and stop receiving emails from it, send an email to golang-nuts+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
