在OS块缓冲区中保留一个文件 [英] Keeping a file in the OS block buffer

问题描述

我需要在操作系统块缓存中保留尽可能多的大文件，尽管它大于我可以放在内存中，而且我不断读取另一个非常大的文件。 ATM我将从系统缓存中删除大块重要的文件，当我流读取形式另一个文件。

解决方案

在一个POSIX系统如Linux或Solaris，请尝试使用posix_fadvise。

在流文件上，执行如下操作：

  posix_fadvise（fd，0，0，POSIX_FADV_SEQUENTIAL）; 
 while（bytes> 0）{
 bytes = pread（fd，buffer，64 * 1024，current_pos）; 
 current_pos + = 64 * 1024; 
 posix_fadvise（fd，0，current_pos，POSIX_FADV_DONTNEED）; 
 
 
 
 $ b $ p 
 $ b你可以将POSIX_FADV_WILLNEED应用到你的其他文件， 。
 
现在，我知道Windows Vista和Server 2008也可以做内存优先级的漂亮技巧。像XP这样的老版本也可以做更多的基本技巧。但是我不知道这些功能是否在我头上，也没有时间查看它们。
I need to keep as much as I can of large file in the operating system block cache even though it's bigger than I can fit in ram, and I'm continously reading another very very large file. ATM I'll remove large chunk of large important file from system cache when I stream read form another file.
解决方案
In a POSIX system like Linux or Solaris, try using posix_fadvise.

On the streaming file, do something like this:
posix_fadvise(fd, 0, 0, POSIX_FADV_SEQUENTIAL);
while( bytes > 0 ) {
  bytes = pread(fd, buffer, 64 * 1024, current_pos);
  current_pos += 64 * 1024;
  posix_fadvise(fd, 0, current_pos, POSIX_FADV_DONTNEED);
}
And you can apply POSIX_FADV_WILLNEED to your other file, which should raise its memory priority.

Now, I know that Windows Vista and Server 2008 can also do nifty tricks with memory priorities.  Probably older versions like XP can do more basic tricks as well.  But I don't know the functions off the top of my head and don't have time to look them up.

                        
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