current_is_kswapd() && sc->priority == DEF_PRIORITY); blk_start_plug(&plug); // 如果LRU_INACTIVE_ANON、LRU_ACTIVE_FILE、LRU_INACTIVE_FILE // 中任意一个没有回收完,都会继续回收 while (nr[LRU_INACTIVE_ANON] || nr[LRU_ACTIVE_FILE] || nr[LRU_INACTIVE_FILE]) { unsigned long nr_anon...
从进程中取得文件描述符后和文件当前的操作位置后会调用vfs_read()执行具体的操作过程.它的代码如下: ssize_t vfs_read(struct file *file, char __user *buf, size_t count, loff_t *pos) { struct inode *inode = file->f_dentry->d_inode; ssize_t ret; if (!(file->f_mode & FMODE_READ)...
count)609{610returnksys_write(fd,buf,count);611}|591ssize_tksys_write(unsignedintfd,constchar__user*buf,size_tcount)592{593structfdf=fdget_pos(fd);594ssize_tret=-EBADF;595596if(f.file){597loff_tpos=file_pos_read(f.file);598ret=vfs_write(f.file,buf,count,&pos);599if(ret>=0)600...
if a read is issued for just-written data that lives in a dirty buffer and is not yet on disk, the request will be satisfied from the buffer and not cause a read from the "stale" data on disk. so the read is satisfied from an in-memory cache without having to go to disk. 延迟...
You will occasionally run into a program that requires this type of redirection, but because most Unix commands accept filenames as arguments, this isn’t very common. For example, the preceding command could have been written as head /proc/cpuinfo. ...
Linux File Permissions in Binary, Octal, String Formats In Linux, file permissions can be expressed in three different ways:Binary,Octal, or aSymbolic stringrepresentation. Here's how each works: 1. Binary Representation Each permission is represented as a bit. Read is4(100in binary), Write is...
There’s a wrinkle, though: You can’t just put old boot loader code into the ESP because that code was written for the BIOS interface. Instead, you must provide a boot loader written for UEFI. For example, when using GRUB, you have to install the UEFI version of GRUB rather than ...
This guide is being written and tested on Debian. Most things below should work on other distributions. If you find something that does not, please contact me. The main thing that separates each distribution will be its package management system. Since I use Debian, I will provide the ...
PercentUsedInodesfilesystem % used inodesPercentage of allocated (in use) inodes summed across all file systems BytesReadPerSecondfilesystem read bytes/secBytes read per second BytesWrittenPerSecondfilesystem write bytes/secBytes written per second ...
You will occasionally run into a program that requires this type of redirection, but because mostUnixcommands accept filenames as arguments, this isn’t very common. For example, the preceding command could have been written as head /proc/cpuinfo. ...