This answer is by no means exhaustive but it may explain it enough to make things click. In virtual memory systems, there is a disconnect between logical and physical addresses. An application can be given a virtual address space of (let’s say) 4G. This is its usable memory and it’s free to use it as …
From what I understand, although I can’t find a definitive source from Apple, unowned can be broken into two flavors, safe and unsafe. A bare unowned is unowned(safe): it is a specially wrapped reference which will throw an exception when a dealloced instance is referenced. The special case is unowned(unsafe): it is the Swift equivalent …
result = [list(someListOfElements) for _ in xrange(x)] This will make x distinct lists, each with a copy of someListOfElements list (each item in that list is by reference, but the list its in is a copy). If it makes more sense, consider using copy.deepcopy(someListOfElements) Generators and list comprehensions and things are considered quite pythonic.
There isn’t much overhead for malloc, so you are unlikely to achieve any run-time savings. There is, however, a good reason to implement an allocator on top of malloc, and that is to be able to trace memory leaks. For example, you can free all memory allocated by the program when it exits, and then …
In the search of answer, I posted the same question on Quora and Robert Love answered it: I’m assuming you are asking this from the point-of-view of the user of a system, or perhaps someone building a kernel for a particular product. As a kernel developer, you don’t care what “slab” allocator is in use; …
Relative to other managed languages like Java and C#, purely functional languages allocate like crazy. They also allocate objects of different sizes. The fastest known allocation strategy is to allocate from contiguous free space (sometimes called a “nursery”) and to reserve a hardware register to point to the next available free space. Allocation from the …
The memory you need to assign to the driver depends on the job. If the job is based purely on transformations and terminates on some distributed output action like rdd.saveAsTextFile, rdd.saveToCassandra, … then the memory needs of the driver will be very low. Few 100’s of MB will do. The driver is also responsible of …
Yes every process has its own pagetables. They might be shared with the parent process(copy on write) or with other processes(shared memory). But in general every process has its own.
In operating systems that implement a virtual memory space the programs allocate memory from an address space that may be much larger than the actual amount of RAM the system possesses. The OS is responsible for deciding which programs “memory” is in actual RAM. It needs a place to keep things while they are “out”. …