On Wednesday, March 22, 2017 at 4:33:21 PM UTC+8, Dave Cheney wrote: > > > > 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. >
except globals and stack objects, are there any other roots? > > >> >> > -- 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.
