Re: splice: move balance_dirty_pages_ratelimited() outside of splice actor

[Andrew Morton <akpm@linux-foundation.org>]

On Tue, 12 Jun 2007 14:44:50 +0200 Jens Axboe <jens.axboe@oracle.com> wrote:

> splice

btw, I'm staring in profound mystification at this:

int generic_pipe_buf_steal(struct pipe_inode_info *pipe,
			   struct pipe_buffer *buf)
{
	struct page *page = buf->page;

	if (page_count(page) == 1) {
		lock_page(page);
		return 0;
	}

	return 1;
}


afacit that `if page_count(page)' test could be replaced by
`if today_is_tuesday()'.  But then I don't have the foggiest idea
what it's trying to do.

It would be nice to get some comments in and around here.

Also, I was trying to work out the role and responsibility of the ->pin
callback, and gave up.

There isn't a lot of point in explaining this over email - one should be
able to gain an understanding of these things by reading the code.  I think
the best way of tackling this would be to comprehensively document
pipe_buf_operations and pipe_inode_info, please...