understanding linux kernel 4th edition

structure starts from the 0x015fa000 address, and the process Kernel stack starts from the ox015fc000 address, the ESP register points to the top of the current stack whose address is 0x015ff878. The kernel uses alloc_thread_info and free_thrad_info macros to allocate and release the thread_info structure and the memory zone of the kernel stack. 5. Two-way linke

Soft Interrupt, tasklet, and working queue are not a mechanism that has always existed in the Linux kernel, but evolved from the "bottom half" (bottom half) of earlier kernel versions. There are actually five mechanisms in the lower half, but in the kernel of version 2.6, the lower half and the functions of the task qu

Deep understanding of the key data structures of Linux kernel network technology-skbuff1, skb- gt; users and skb- gt; dataref differences skb- gt; users: when the number of references increases, this value and skb- gt; dataref both increase skb- gt; dataref: when skb is cloned, only sk... deep understanding of the key

programmingThe local APIC timer sends interrupts only to its own processor, and the pit generates a global outage that any CPU can handle.The APIC timer is based on the clock signal, and the pit is based on internal clock oscillation.High Accuracy Event Timer (HPET):Linux time-of-mind architecture:The kernel periodically performs timing-related operations:1, updated since the system started the time elapse

Deep understanding of Linux kernel -- skbuff1, skb- gt; users and skb- gt; dataref differences skb- gt; users: when the number of references increases, this value and skb- gt; dataref will both add skb- gt; dataref: when skb is cloned, only skb- gt; dataref will be added, and clon... deep understanding of

Understanding of the upper half and lower half of the Linux kernel-general Linux technology-Linux programming and kernel information. The following is a detailed description. The activities of the operating system core during runn

A deep understanding of the Linux kernel Chinese Version 2 (pdf)-Linux general technology-Linux programming and kernel information. The following is a detailed description. I sent a message last summer. Today, I accidentally en

Access mode of the file:1. Standard mode:2. Synchronous mode:3. Memory Mapping Mode:4. Direct i\o mode5. Asynchronous mode:Memory-Mapped mode:1. Shared type: Any write operation on the linear Zone page modifies the files on the disk, and this modification is visible to all processes that map the same file.2, Private type: process to create read-only files when used, more efficient. Write to it does not alter the disk file and is not visible to other processes.3, the creation of the memory map is

with segments, Linux prefers paging, This is because memory management becomes easier when all processes use the same segment register value. one of the Linux design goals is to be transplanted to most processor platforms, while Limited support. Linux mainly uses four segments: user segments, user segments, kernel se

first checks the TI field of the segment selection operator to determine the storage location of the segment descriptor (GDT or LDT). If it is GDT, the segment unit starts from the gdtr register.To obtain the linear base address of GDT. If it is an active LDT, the segment Unit obtains the linear base address of LDT from the ldtr register. Then, the segment descriptor address of the index field is selected from the segment, setThis address is added to the offset field value in the logical addres

buffer into the request queue. 5. memory allocation and processingMemory processing This block is designed to be more personalized, allowing memory allocations to be customized and custom functions placed in a struct called v4l2_alloc_ctx. Its purpose is to provide videobuf with operational functions and to store some private data. Private data can be embedded in a larger number of structures. Struct Vb2_alloc_ctx {const struct VB2_MEM_OPS *mem_ops;}struct VB2_FOO_ALLOC_CONF {STRUCDT Vb2_

Are you an application of Linux? Do you know about Linux kernel? This article introduces you to the Linux kernel. Share with you. The Linux kernel consists of five subsystems: process s

-mapped I/O ports and peripheral memory as "I/O memory" resources.In general, when the system is running, the physical address of the peripheral I/O memory resources is known and determined by the hardware design. However, CPUs typically do not have predefined virtual address ranges for the physical addresses of these known peripheral I/O memory resources. Instead of accessing the I/O memory resources directly through physical addresses, the drivers must map them to the core virtual address spac

kernel uses three different mechanisms to solve this problem: 1. The copy-on-write technology allows the Parent and Child processes to read the same physical page. 2. Lightweight processes allow Parent and Child processes to share many data structures in the kernel, such as page tables, open file tables, and process signals. 3. The process created by the vfork () system call can share the memory address of

kernel uses three different mechanisms to solve this problem: 1. The copy-on-write technology allows the Parent and Child processes to read the same physical page. 2. Lightweight processes allow Parent and Child processes to share many data structures in the kernel, such as page tables, open file tables, and process signals. 3. The process created by the vfork () system call can share the memory address of

regard memory ing I/O Ports and peripheral memory as "I/O memory" resources. Generally, when the system is running, the physical address of the peripheral I/O memory resources is known and determined by the hardware design. However, the CPU generally does not pre-define the virtual address range for the physical addresses of these known peripheral I/O memory resources, and the driver cannot directly access the I/O memory resources through the physical address, instead, you must map them to the

In-depth understanding of the Linux kernel, there are three chapters on memory management, this is a chapter, and the eighth chapter discusses how the kernel assigns itself main memory, and the Nineth chapter, considering how to assign a linear address to a process. Memory Address--(P40) The following thr

passed inProcess 0:swapper process, idle process; in multiprocessor systems, each CPU has a process 0Process 1: The kernel process, which shares data with process 0, also known as the Init process, creates and monitors all process activity performed on the outer layer of the operating system.4. Revocation of the processExit (): System call to terminate a processExit_group (): System call, terminating the entire thread groupZombie Process: One reason

Kernel options during boot Linux users pass the Kernel configuration options to the Boot Record, The Boot Record, and then the options to the kernel, and then fine-tune the kernel through the boot configuration parameters. During system boot, parse_args is called to parse th

()#define Raw_local_irq_restore (flags) Arch_local_irq_restore (Flags)The following is an example of the implementation of the functions of Arch_local_irq_save () and Arch_local_irq_restore () x86.3. Arch_local_irq_save () and Arch_local_irq_restore () the implementation of these two functions on the x86/*linux-4.14.12/arch/x86/include/asm/irqflags.h#70*/ - StaticInline Notrace unsignedLongArch_local_save_flags (void) in { the returnNative_