linux - 什么是私有(private)页面？

Question

在页面结构中，有私有(private)字段。如果我使用 page_buffers() 函数，它们会返回该字段。

还有 PrivatePage()。但我不知道它是什么。

这是什么？

Answer 1

参见 include/linux/page-flags.h:

 * Private page markings that may be used by the filesystem that owns the page
 * for its own purposes.
 * - PG_private and PG_private_2 cause releasepage() and co to be invoked

还有 Documentation/filesystems/vfs.txt:

An address_space handler may attach extra information to a page, typically using the 'private' field in the 'struct page'. If such information is attached, the PG_Private flag should be set. This will cause various VM routines to make extra calls into the address_space handler to deal with that data.

page_buffers() 适用于 private 字段包含指向 struct buffer_head 的指针的特定情况，这是一种非常常见的模式在文件系统驱动程序中。