virtual-memory

On Mac OSX 5.8 I have a Java program that runs at 100% CPU for a very long time -- several days or more (it's a model checker analyzing a concurrent program, so that's more or less expected). However, its virtual memory size, as shown in OSX's Activity Monitor, becomes enormous after a day or so: right now it's 16GB and growing. Physical memory usage is roughly stable at 1.1GB or so. I would like to know: is the 16GB (and growing) a sign of problems that could be slowing my program? I start the program with "java -Xmx1024m -ea" java version "1.6.0_24" Java(TM) SE Runtime Environment (build 1.6

The parent process fails with errno=12(Out of memory) when it tries to fork a child. The parent process runs on Linux 3.0 kernel - SLES 11. At the point of forking the child, the parent process has already used up around 70% of the RAM(180GB/256GB). Is there any workaround for this problem? The application is written in C++, compiled with g++ 4.6.3. Maybe virtual memory over commit is prevented in your system. If it is prevented, then the virtual memory can not be bigger than sizeof physical RAM + swap. If it is allowed, then virtual memory can be bigger than RAM+swap. When your process forks,

I have the following page table of process1 : Assuming that the paging system works with 16bit addresses and page size is 4k And I want to convert the logical address 16000 to a physical address . I'm a little bit new in this topic so go easy on me : Partial solution : The address 16000 fits cell number 3 in the page table , so I guess that I need to work with that cell and its stored frame - 2 . How can I find the offset and the physical address now ? Thanks In your case process 1 currently can access upto 4 * 4k bytes of virtual memory. Generally a process can access upto 4gb of virtual

I would like to know architectures which violate the assumptions I've listed below. Also, I would like to know if any of the assumptions are false for all architectures (that is, if any of them are just completely wrong). sizeof(int *) == sizeof(char *) == sizeof(void *) == sizeof(func_ptr *) The in-memory representation of all pointers for a given architecture is the same regardless of the data type pointed to. The in-memory representation of a pointer is the same as an integer of the same bit length as the architecture. Multiplication and division of pointer data types are only forbidden by

I have a memory segment which was obtained via mmap with MAP_ANONYMOUS . How can I allocate a second memory segment of the same size which references the first one and make both copy-on write in Linux (Working Linux 2.6.36 at the moment)? I want to have exactly the same effect as fork , just without creating a new process. I want the new mapping to stay in the same process. The whole process has to be repeatable on both the origin and copy pages (as if parent and child would continue to fork ). The reason why I don't want to allocate a straight copy of the whole segment is because they are

Which addressing is used in processors x86/x86_64 for caching in the L1, L2 and L3(LLC) - physical or virtual(using PT/PTE and TLB ) and somehow does PAT(page attribute table) affect to it? And is there difference between the drivers(kernel-space) and applications(user-space) in this case? Short answer - Intel uses virtually indexed, physically tagged (VIPT) L1 caches: What will be used for data exchange between threads are executing on one Core with HT? L1 - Virtual addressing (in 8-way cache for define Set is required low 12 bits which are the same in virt & phys) L2 - Physical addressing