On Sun, Feb 23, 2003 at 12:49:31AM -0800, Terry Lambert wrote: > I've been unable to find any documentation on get_user_pages(), > and you didn't provide a link to any. > > But looking at the source code, the reason for doing this is to > permit DMA directly into user pages. > > I don't understand what you mean by "pin", in this context.
get_user_pages() does the following: (1) force all pages into physical memory if they weren't before (2) increment the usage count on the to avoid paging them out The latter is usually called page pinning. > You are aware that FreeBSD has a unified VM and buffer cache, and > all user pages for the current process are automatically visible > in th kernel address space, with no need to call something like > get_user_pages() to establish a mapping, right? get_user_pages() does not establish a mapping, in Linux you don't need a kernel mapping to perform DMA on memory. To Unsubscribe: send mail to [EMAIL PROTECTED] with "unsubscribe freebsd-hackers" in the body of the message
