Hello.

On Maw, 2004-08-17 at 00:35, Dave Hansen wrote:

quoted

In any case, the question of the day is, does anyone have any
suggestions on how to create 2 separate pools for pages: one
representing hot-removable pages, and the other pages that may not be
removed?

How do you define the split. There are lots of circumstances where user
pages can be pinned for a long (near indefinite) period of time and used
for DMA.

Basically, kernel have to wait of completion of I/O.

Consider
- Video capture
- AGP Gart
- AGP based framebuffer (intel i8/9xx)

I didn't consider deeply about this, because usually
enterprise server doesn't need Video capture feature or AGP.
It is usually controlled from other machine.

If it is really necessary, kernel might have to wait 
I/O completion or driver modification is necessary.

- O_DIRECT I/O

I can use page remmaping method by Iwamoto-san.
(See: http://people.valinux.co.jp/~iwamoto/mh.html#remap)
I guess that many case can be saved by this.

There are also things like cluster interconnects, sendfile and the like
involved here.

In sendfile case, kernel will wait too. Sooner or later, it will be
timeout.

Thank you for your comment.
Bye.

-- 
Yasunori Goto <ygoto at us.fujitsu.com>


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