I have VMWare install CentOS 5.5 and deploy some java application. I want to know how much memory remain, As I use command below, All memory is use. But when I check with top command, all process use “0.0%” of memory. So I want to know what happen? What really memory usage on this VM? Regards, Sathit Answer i think
Tag: memory
C++ Sockets – Client gives segmentation fault (linux)
I created a server/client connection. The server and client both are compiling correctly but when I run the client, it gives me a Segmentation Fault (core dumped) I don’t know what I am doing wrong with my memory allocations. The program is not dangling or anything. I think my program is writing to a read-only portion of the memory, or
How to trap memory reads and writes using sigsegv?
How do I trick linux into thinking a memory read/write was successful? I am writing a C++ library such that all reads/writes are redirected and handled transparently to the end user. Anytime a variable is written or read from, the library will need to catch that request and shoot it off to a hardware simulation which will handle the data
BASH: check for amount of memory installed on a system as sanity check
As part of a bash install script, I’d like the script to do a sanity check that the target machine has at least a given amount of memory installed. Note that I’m NOT specifically worried about how much memory is currently used or allocated or available – for my purposes the existance of more than XXX GB of RAM in
What is the best practice for kdump disk size
We have a redhat 6 servers and memory is around 64GB, we are planing to configure kdump and I am confused about disk size I should set. Redhat suggest it would be memory + 2% more (that means around ~66GB Disk space). I need your suggestion what would be the best size I should define for kdump. Answer First, don’t
High mem in arm Architecture
High memory (highmem) is used when the size of physical memory approaches or exceeds the maximum size of virtual memory. The traditional split for architectures using this approach is 3:1, 3GiB for userspace and the top 1GiB for kernel space. This means kernel can at most map 1 GiB of physical memory. In mobile devices average physical memory present is
Setting limit to total physical memory available in Linux
I know that I am supposed to set mem=MEMORY_LIMIT. But I do not know where to go, during runtime, or during boot time, in order to set a limit to the total physical memory that the OS has control of. I am running I/O benchmarks, and I would like to limit the amount of overall physical memory that is available.
How to access physical addresses from user space in Linux?
On a ARM based system running Linux, I have a device that’s memory mapped to a physical address. From a user space program where all addresses are virtual, how can I read content from this address? Answer You can map a device file to a user process memory using mmap(2) system call. Usually, device files are mappings of physical memory
32-bit process’s address space on 64-bit linux
In this answer author states: With the 64-bit x86_64 kernel, a 32-bit process can use the entire 4GB address space, except for a couple pages (8KB) at the end of the 4GB address space which are managed by the kernel. What is the purpose of this kernel-managed memory? Shouldn’t it be in the kernel space, to prevent accidental corruption by
Increasing the caching capability of MySQL
My mysql only caters read requests. I thought, it will be a good idea to make use of the cache completely. I am running MySQL in a VM and that is the only application running inside the VM. I am allocating 2GB memory for that VM. I am using a 64 bit centos on the VM. If you think already