mmap mindmap

BaseExpandableListAdapter {private LinkedHashMap > MMap; private Context mContext; private CategoryExpandGridAdapter categoryExpandGridAdapter; public CategoryExpandAdapter (Context context, LinkedHashMap > Map) {this. mContext = context; this. mMap = map;} @ Override public int getGroupCount () {Set KeySet = mMap. keySet (); return keySet.

); } Return 0; } Int v4l_get_capability (v4ldevice * vd) { If (ioctl (vd-> fd, VIDIOCGCAP, (vd-> capability) { Perror ("v4l_get_capability :"); Return-1; } Return 0; } Int v4l_get_picture (v4ldevice * vd) { If (ioctl (vd-> fd, VIDIOCGPICT, (vd-> p

shared resources protected by the read/write semaphores when the writer maintains the read/write semaphores, for those who do not need to write access under the current conditions, the downgrading will enable the readers waiting for access to access immediately, thus increasing concurrency and improving efficiency. 　　 The read/write semaphores are suitable for reading and writing less data. in the Linux kernel, the read/write semaphores are used to protect access to the memory image description

register in bulk, set the colour table */Int (*fb_setcmap) (struct fb_cmap *cmap, struct fb_info *info); 　　 /* Show Blank */Int (*fb_blank) (int blank, struct fb_info *info);/* Pan Display */Int (*fb_pan_display) (struct fb_var_screeninfo *var, struct fb_info *info); 　 /* Rectangle Fill */Int (*fb_fillract) (struct fb_info *info, const struct fb_fillrect *rect);/* Data replication */void (*fb_copyarea) (struct fb_info *info, const struct Fb_copyarea *region);/* Graphics Fill */void (*fb_imagebl

operating system perspective, the process allocates memory in two ways, with two system invocations:BRK and mmap (regardless of shared memory). 1, BRK is the data segment (. data) The highest address pointer _edata to the high address of the push;2, Mmap is in the virtual address space of the process (heap and the middle of the stack, called the file map area ) to find a piece of free virtual memory .Both

Rookie Nginx Source analysis data Structure (11) shared memory ngx_shm_t Author:echo Chen (Chenbin) Email:[email protected] blog:blog.csdn.net/chen19870707 Date:nov 14th, 20141. Shared memory Shared memory is the most basic process communication method provided under Linux, which creates a contiguous linear address space in memory through MMAP or shmget system calls, and frees the memory through Munmap or SHMDT system calls. The b

This is a creation in Article, where the information may have evolved or changed. the memory between the different processes is independent of each other, there is no way to directly manipulate each other's data, while the shared memory is provided by the operating system memory mapping mechanism, so that the different processes of a single address space mapped to the same virtual memory area, so that different processes can operate to a common block of memory. Shared memory is the most efficien

[Switch] php accelerates PHPAPC analysis PHPAPC provides two caching functions: cache Opcode (target file), which we call apc_compiler_cache. It also provides some interfaces for PHP developers to resident user data in the memory, which is called apc_user_cache. Here we mainly discuss the configuration of php-apc. Install PHPAPC as the Test environment. here we use Cent [to] php acceleration php apc analysis Php apc provides two caching functions: cache Opcode (target file), which is called apc_

This is a creation in Article, where the information may have evolved or changed. The memory between the different processes is independent of each other, there is no way to directly manipulate each other's data, while the shared memory is provided by the operating system memory mapping mechanism, so that the different processes of a single address space mapped to the same virtual memory area, so that different processes can operate to a common block of memory. Shared memory is the most efficien

leak 64M memory every time so coincidence, in order to prove my point of view, first of all, I used valgrind. 1:valgrind--leak-check=full--track-fds=yes--log-file=./authserver.vlog Then start the test and run to memory no longer, and sure enough valgrind show no memory leaks. Repeated trials many times, the result is this. After using valgrind many times, I began to wonder if the program was using MMAP and other calls, and then

http://blog.csdn.net/woshi250hua/article/details/7824773#include #includestring>#include#include#include#include#include#include#include#include#include#include#includeSet>#include#includeusing namespacestd;#defineMem (A, B) memset (A,b,sizeof (a))#definePF printf#defineSF scanf#defineSPF sprintf#definePB Push_back#defineDebug printf ("!\n")#defineMAXN 1010#defineMAX (A, b) a>b?a:b#defineBlank pf ("\ n")#defineLL Long Long#defineAll (x) X.begin (), X.end ()#defineINS (x) Inserter (X,x.begin ())#

efficiency. The read/write semaphores are suitable for reading and writing less data. In the Linux kernel, the read/write semaphores are used to protect access to the memory image description structure of processes. In Linux, each process is described by a structure of task_t or struct task_struct. The field mm of the Structure of struct mm_struct describes the memory image of the process, in particular, the mmap field in the mm_struct structure main

is the Linux kernel space, shared by all the processes and kernels of the system. By accessing the relevant files in/proc/{pid}/, you can understand the usage of virtual memory space of each thread and how much memory is consumed by each thread. Because our products are implemented in multi-thread mode, multiple threads share the user-state virtual address space of a process. The virtual address space contains several areas, mainly including the following areas: 1. The code segment of the curre

Memory ing and DMA, memory ing DMA 1. the implementation process of mmap system calling. The system calling directly maps the device memory to the address space of the user process. 2. How to map the user space memory to the kernel (get_user_pages ). 3. Direct Memory Access (DMA), which enables peripherals to directly access the system memory. Address type in linux: User Virtual Address, kernel virtual address, kernel logical address (linear relation

parameters of Virt, res and SHR in the top command; The last part introduces you to the format of the Smaps file, By analyzing the Smaps file we can learn more about the usage of the process's physical memory, such as how much space the Mmap file occupies, how much space is consumed by dynamic memory, how much space is consumed by the function call stack, and so on.two concepts about memoryTo understand the output of the top command with regard to me

There are two main tasks for a device driver:1. Accessing the device's memory2. Interruption of processing equipmentFor the first task. The UIO core implements the Mmap () capable of handling physical memory (physical memory), logical (logicalVirtual memory. The UiO drive is written without the need to consider these tedious details.For the second task, the answer to the device interrupt must be in kernel space. So there's a small piece of code in the

There are two main tasks for a device driver:1. Accessing the device's memory2. Interruption of processing equipmentFor the first task, the UIO core implements the Mmap () to handle the physical memory (physical memory), the logical RAM (logical memories),Virtual memory. UiO driver Writing is no need to consider these cumbersome details.For the second task, the answer to the device interrupt must be in kernel space. So there's a small piece of code in

Simple Introduction Many types of driver programming require knowledge of how some virtual memory subsystems work When it comes to more complex, performance-demanding subsystems, the content discussed in this chapter will sooner or later be used The contents of this chapter are divided into three parts Describe the implementation process for MMAP system calls Describes how to access the memory pages of use

struct variable to the image format supported by the video device, so in program design, after all the video formats are set, to get the actual video format, re-read struct V4l2_format struct-body variable.4. Control command VIDIOC_REQBUFS//I don't ask, you ask yourself.Function: Request V4L2 driver to allocate video buffer (request V4L2 video Drive allocated memory), V4L2 is the driving layer of video device, located in kernel space, so the memory requested by VIDIOC_REQBUFS Control command Wo

This article analyzes the way of shared memory reading and writing in Go language. Share to everyone for your reference. The specific analysis is as follows: The previous analysis of the Go language pointer operation and embedded C code method, do a go language shared memory reading and writing experiment. Let's talk about what is shared memory. We know that the memory that the different processes see is independent of each other, there is no way to directly manipulate each other's data, while