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When an server process starts it issues some system calls (socket() and listen()). The system then opens the port and creates a socket file descriptor for the process to interact with. You can see this with: Find the Apache master process id: root@frisbee:~# ps -ef | grep apache | grep root root 27440 1 0 16:06 ? 00:00:00 /usr/sbin/apache2 ...


3

There is no difference betweem tmpfs and shm. tmpfs is the new name for shm. shm stands for SHaredMemory. See: Linux tmpfs. The main reason tmpfs is even used today is this comment in my /etc/fstab on my gentoo box. BTW Chromium won't build with the line missing: # glibc 2.2 and above expects tmpfs to be mounted at /dev/shm for # POSIX shared memory ...


2

Swapping only when there is no free memory is only the case if you set swappiness to 0. Otherwise, during idle time, the kernel will swap memory. In doing this the data is not removed from memory, but rather a copy is made in the swap partition. This means that, should the situation arise that memory is depleted, it does not have to write to disk then and ...


1

LUKS is a block device encryption layer which sits on top of a block device and encrypts/decrypts all accesses to that device. No unencrypted data ever touches the physical device. LUKS then provides a virtual block device which gets used by the system to access the files. It is thus transparent to applications, which have no idea that encryption is taking ...


1

There's no difference between shm and tmpfs (actually, tmpfs is only the new name of former shmfs). hugetlbfs is a tmpfs-based filesystem that allocates its space from kernel huge pages and needs some additional configuration afford (how to use this is explained in Documentation/vm/hugetlbpage.txt).


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Another way to limit this is to use Linux's control groups. This is especially useful if you want to limit a process's (or group of processes') allocation of physical memory distinctly from virtual memory. For example: $ cgcreate -g memory:/myGroup $ echo $(( 500 * 1024 * 1024 )) > /sys/fs/cgroup/memory/myGroup/memory.limit_in_bytes $ echo $(( 5000 ...



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