In C there are some differences however: fork() Purpose is to create a new process, which becomes the child process of the caller Both processes will execute the next instruction following the fork() system call Two identical copies of the computer’s address space,code, and stack are created one for parent and child. Thinking of the … Read more
As of Mon 2022-09-19, the Linux kernel is typically compiled with gcc -std=gnu11, which supports the GNU dialect of the 2011 edition of the ISO C standard. Reference: https://www.kernel.org/doc/html/latest/process/programming-language.html The kernel is written in the C programming language. More precisely, the kernel is typically compiled with gcc under -std=gnu11: the GNU dialect of ISO C11. … Read more
Motivation The .config file is not simply copied from your defconfig file. The motivation for storing defconfig in such a format is next: in defconfig we can specify only options with non-default values (i.e. options we changed for our board). This way we can keep it small and clear. Every new kernel version brings a … Read more
Text from https://access.redhat.com/site/documentation/en-US/Red_Hat_Enterprise_Linux/7-Beta/html/Resource_Management_and_Linux_Containers_Guide/sec-Linux_Containers_Compared_to_KVM_Virtualization.html Copyright © 2014 Red Hat, Inc.: Linux Containers Compared to KVM Virtualization The main difference between the KVM virtualization and Linux Containers is that virtual machines require a separate kernel instance to run on, while containers can be deployed from the host operating system. This significantly reduces the complexity of container creation … Read more
Device trees do not need to be compiled with “architecture-aware” tools. The dtc compiler on your ubuntu machine is probably current enough to compile your device tree. Or you can download the latest source and compile it yourself. The dtc compiler can be found here: https://git.kernel.org/pub/scm/utils/dtc/dtc.git There are some good documents in that package that … Read more
Pretty much correct. To me, “linux” is just the kernel. But it is pretty common to refer to entire distributions as linux. That is what annoys RMS so much. He maintains it should be called GNU/Linux, as he sees distributions as the linux kernel plus the additional software from the GNU project. This makes sense … Read more
Not all virtual (linear) addresses must be mapped to anything. If the code accesses unmapped page, the page fault is risen. The physical page can be mapped to several virtual addresses simultaneously. In the 4 GB virtual memory there are 2 sections: 0x0… 0xbfffffff – is process virtual memory and 0xc0000000 .. 0xffffffff is a … Read more
So what stops the scehduler from putting interrupt context to sleep and taking next schedulable process and passing it the control? The problem is that the interrupt context is not a process, and therefore cannot be put to sleep. When an interrupt occurs, the processor saves the registers onto the stack and jumps to the … Read more
More specifically, from the Redis FAQ Redis background saving schema relies on the copy-on-write semantic of fork in modern operating systems: Redis forks (creates a child process) that is an exact copy of the parent. The child process dumps the DB on disk and finally exits. In theory the child should use as much memory … Read more
From the kernel’s perspective, see /usr/src/linux/Documentation/firmware_class/README: kernel(driver): calls request_firmware(&fw_entry, $FIRMWARE, device) userspace: – /sys/class/firmware/xxx/{loading,data} appear. – hotplug gets called with a firmware identifier in $FIRMWARE and the usual hotplug environment. – hotplug: echo 1 > /sys/class/firmware/xxx/loading kernel: Discard any previous partial load. userspace: – hotplug: cat appropriate_firmware_image > \ /sys/class/firmware/xxx/data kernel: grows a buffer in … Read more