mmap mindmap

differences between these two sets of caching systems, you can understand exactly what they can be used to do.What is page cachePage cache is used primarily as a cache of file data on the file system, especially when the process has read/write operations on the file. If you think about it, as a system call that can map files to memory: Mmap is it natural that you should also use page cache? In the current system implementation, the page cache is also

functionality. That is, before the first process finishes writing on shared memory, there is no automatic function to prevent the second process from starting to read it. The problem of access synchronization for shared memory must be the responsibility of the programmer. Optional synchronization methods include mutual exclusion lock, conditional variable, read-write lock, record lock, Semaphore. Second, mmap We'll introduce the following functions

/debug/gpioYou can see that the system has occupied the following IO ports:The first GPIO17 is PA17, which is configured as output mode by default and is set to low level. Here need to explain the system in the GPIO port numbering method, the system is in accordance with PA~PL a total of 12 groups, each group of 32 pins to the IO port unified number, such as, GPIO-0~GPIO-31 for PA port io,gpio-32~gpio-63 for PB port Io, And so on So the last line GPIO-362 is actually the PL10 pin, which is the g

This article focuses on the frame capture method and transfers the focus from video4linux to the network. In terms of instant transfer of network images, RTP is also the standard used by major manufacturers. In this phase, we will be able to learn how to use jrtplib To add network functions. Video4linux frame capture method In the last issue of xawtv, we saw the image capture function of xawtv, Among them, the most important part is to use video4linux for image retrieval. As long as you can writ

The "abstract" kernel-to-user-space address mapping in Linux allows the user-level application to directly access the kernel address, which is the Mmap method. The application can directly access the device's I/O storage or DMA buffers through memory mapping. A Memory map associates a segment of the user space with the device's memory, and the program reads or writes within the mapped address range, which is actually access to the device.struct file_o

of sizeof (struct rte_mem_config) in the/var/run/. rte_config file MMAP. Rte_config.mem_config =/var/run/. rte_config the first address of the MMAP file; 1 struct rte_config {2 uint32_t master_lcore; /** The data structure of struct rte_mem_config is as follows: 1 struct rte_mem_config { 2 volatile uint32_t magic; /** 2.3 rte_eal_hugepage_init () Rte_eal_hugepage_init () is mainly used to

; while(ILast ) { if(Num[i] Num[j]) {Mmap[index+ +] = num[i++]; } Else{Mmap[index+ +] = num[j++]; } } while(imid) {Mmap[index+ +] = num[i++]; } while(J Last ) {Mmap[index+ +] = num[j++]; } for(intm=0; m) {Num[first++] =Mmap[m]; }}voidMergeSort (

Linux inter-process communication (IPC) programming practices (8) use of shared memory-POSIX shared memory (API) 1. Posix provides two methods to share memory areas between unrelated processes: (1) memory ing file: open the function first, and then call the mmap function to map the obtained descriptor to a file in the current process address space (this is used in the previous blog ). (2) shared memory area object: First open a Posix IPC name (or a pa

, but a library function. SBRK (+/-n) means to increase/decrease N bytes for the current fetch limit.void *mmap (void *addr, size_t len, int prot, int flags, int fildes, off_t off);int Munmap (void *addr, size_t len);The use of Mmap:mmap () is more flexible and more versatile than BRK (). The virtual memory address can be mapped to a file, shared memory, etc., so that users read and write files in a way to complete interprocess communication. Of cours

Virtual Turn Physical Address Virt_to_phys (*ADDR);Physical to Virtual address phys_to_virt (*ADDR);Such as: Long Pprotectva; phys_addr_t protectpa; = Pprotectva; = Virt_to_phys ((void *) pprotectva);-------------------------------------------------The/dev/mem driver provided in the Linux kernel provides a channel for us to read and write memory physical addresses. Here are 2 ways to use MEM device files to read and write physical addresses, one is device-driven, the other is the m

?Page cache is used primarily as a cache of file data on the file system, especially when the process has read/write operations on the file.If you think about it, as a system call that can map files to memory: Mmap is it natural that you should also use page cache? In the current system implementation, the page cache is also used as a caching device for other file types, so in fact page cache is responsible for most of the block device file c

cache?Page cache is used primarily as a cache of file data on the file system, especially when the process has read/write operations on the file.If you think about it, as a system call that can map files to memory: Mmap is it natural that you should also use page cache?In the current system implementation, the page cache is also used as a caching device for other file types, so in fact page cache is responsible for most of the block device file cachi

Heap heap allocation at the user level: malloc function for heap memory allocationvoid malloc (size_t size); Virtual memory address layout for the process:For users, the primary focus is on user space. After you enlarge the user space, you can see that it is mainly divided into the following sections: Code: This is the lowest address part of the entire user space, which is the instruction (the executable machine code compiled by the program) Data: The initialized global v

; Struct iovec iov; Struct page * pages [5]; Uid = getuid (); Gid = getgid (); Setresuid (uid, uid, uid ); Setresgid (gid, gid, gid ); Printf ("----------------------------------- \ n "); Printf ("Linux vmsplice Local Root Exploit \ n "); Printf ("By qaaz \ n "); Printf ("----------------------------------- \ n ");

I have always been vague about the concept of memory ing files. I don't know what is the difference between it and virtual memory, and the word ing is also confusing. I finally figured it out today... Next, I will explain my understanding of the ing term first, and then distinguish between several confusing concepts. Then, it will be clear what memory ing is. Principle First of all, the word "ing" means a one-to-one ing with the math, that is, establishing a one-to-one ing relationship. HereFi

Required ProgramHttp://pvpgn.cyfxstudios.com/main.htmlPvpgn-1.6.5.tar.bz2Pvpgn support files 1.0 (nix)Battlenet gateway Editor (PC)W3l.exeInstallation instructionsHttp://pvpgn.ez15loan.com/Http://www.lostcity.cn/bbs/index.php? Showforum = 12Http://www.soarchin.com/Chroot pvpgnThe installation path is/home/pvpgn.Create the directory required by chrootMkdir-P/chroot/{home, bin, sbin, Dev, etc, TMP, usr/lib, usr/libexec, var/run, var/log}Chmod 1777 TMPTruss/hoem/pvpgn/sbin/bnetdKid # truss/home/pvp