mmap mindmap

addresses to user Spaces Generally, the user space cannot or should not directly access the device. However, the mmap () function can be implemented in the device driver. This function allows the user space to directly access the physical address of the device, mmap () associates a memory segment of the user space with the device memory. When the user accesses the user space, the address segment is actuall

have 16 m and 64Mswap. Everyone is satisfied with this optimistic approach. The kernel has corresponding parameters to adjust the overcommitment. There are two types of pages: anonymous pages and file pages. When you create an mmap () file on the disk, the file page is generated. The anonymous page is from malloc (). They are not related to files. When the memory is insufficient, the inner core switches anonymous pages out and clears the file pag

file. 3. a heap that stores global variables and dynamically generated data. 4. stack for saving local variables and implementing function calls. 5. use mmap to map memory segments in the virtual address space Therefore, you only need to view the user-State virtual address space allocation of any thread to know the total memory occupied by all threads of the same process. You can view the/proc/{pid}/maps file to obtain the relevant virtual address sp

(system administrators often use some hacking techniques to protect their systems ). 　　 So how should we continue? 　　 　　 2.2.1 discovering interesting system calls (strace method) 　　 Suppose you already know the program used by a system administrator to check the system (this can be obtained through some other methods, such as TTY hijacking (see 2.9/appendix 　　 A) now the only problem is that you need to keep your gift away from the system administrator program .....). 　　 Well, run this program

INB () Outb (), and then release the I/O port range when the device is closed or the drive is unloadedAnother way is to map the I/O port to memory for access, to request the I/O Port region and map to memory using Ioport_map () when the device is open or the driver module is loaded, and then use the I/O memory function for port access. Finally, release I/O and use the mapping when the device shuts down or the drive is unloadedc) How I/O memory is accessedFirst use Request_mem_region () to reque

B.liunxFirst step: Download and installwget http://pecl.php.net/get/APC-3.1.8.tgzTAR-ZXVF apc-3.1.8.tgz CD APC-3.1.8/usr/local/php/bin/phpize./configure--ENABLE-APC--enable-mmap--enable-apc-spinlocks--disable-apc-pthreadmutex--with-php-config=/usr/ Local/php/bin/php-configMakesudo make installStep Two: Configure APCAdd the following configuration items to/usr/local/php/etc/php.ini: Copy Code code as follows: Extension = "apc.so"; ; A

Shared Memory Based mapping file#include #include #include #include typedef struct {Char name[4];int age;} people;int main (int argc, char **argv){int FD, I;People *p_map;char temp;FD = open (argv[1], o_creat | O_rdwr | O_trunc, 00777);Lseek (FD, sizeof (people) * 5-1, Seek_set);Write (FD, "", 1);P_map = (people*) mmap (NULL, sizeof (People) *, Prot_read | Prot_write,map_shared, FD, 0);Close (FD);temp = ' a ';for (i = 0; i {temp + = 1;memcpy ((* (P_ma

border.However, the virtual memory is now exclusive, how to manage the physical memory has been stripped out, so there is no need to use the original way.Note that there is no problem with internal and external fragments, because in the age of protection mode, a much larger, exclusive address space can be used to efficiently avoid both fragments with a well-designed memory management algorithm. And in prehistoric times. Minimal shared memory is insufficient to accommodate the complex memory man

: Mode 1 and Mode 2 each called several copy constructors. why. } Refer to the "self-cultivation of the programmer" P305 4. memory-Mapped segment: here, the kernel maps the contents of hard disk files directly to memory, and any program can request this mapping via Linux mmap system calls. Memory mapping is a convenient and efficient way of file i/0, so it is used to load dynamic shared libraries. Users can also create an anonymous memory map, whic

) 8564 KB:com.baidu.input (PID 2999) 5298 Kb:c Om.android.phone (PID 959) 4443 KB:com.apical.dreamthemetime (PID 4448) 4203 kB:com.csr.csrservices (PID 982) 4130 KB:com.apical.apicalradio (PID 4518) Total PSS by OOM adjustment:16094 Kb:system 16094 kb:syste M (PID 782) 21110 kb:persistent 11609 kB:com.android.systemui (PID 851) 5298 KB:com.and Roid.phone (PID 959) 4203 kB:com.csr.csrservices (PID 982) 36924 Kb:foreground 36924 KB: Com.android.launcher (PID 2683) 85759 kb:perceptible 41743 k

implemented differently, but its basic form is:struct stat{Mode St_mode; /* File type and mode (license number) * *Ino st_ino;/* I-node number (serial number) * *Dev st_dev;/* Equipment Number (file system) */Dev st_rdev;/* device number for special file * *Nlink st_nlink;/* Connection Number * *UID st_uid;/* owner's user id*/GID st_gid;/* Group id*/Off st_size;/* byte length of normal file * *Time st_atime;/* Last access times * *Time st_mtime;/* last modified access times * *Time st_ctime;/*

or the system cache, the general process is similar, the steps are as follows:Position the current key in the slots array by finding the remainder operation: cache->slots[key.h% cache->num_slots];After locating the position in the slots array, iterate through the slot list of the current key, clearing the current slot if there is a key in the slot and a key match to write or the slot expires.Insert a new slot after the last slot.Second, APC module installationInstalling APC under A.windowsFirst

"], [/* 50 vars */]) = 0 BRK (0) = 0x1033000 Access ("/etc/lD. So. nohwcap", f_ OK) =-1 enoent (no such file or directory) MMAP (null, 8192, prot_read | prot_write, map_private | map_anonymous,-1, 0) = 0x7f64fa550000 Access ("/etc/lD. So. preload", r_ OK) =-1 enoent (no such file or directory) Open ("/etc/lD. So. cache", o_rdonly | o_cloexec) = 3 Fstat (3, {st_mode = s_ifreg | 0644, st_size = 77020,...}) = 0 MMAP