Re: page_launder() bug

Marcelo Tosatti
2001-05-08T20:32:21Z

On Tue, 8 May 2001, Linus Torvalds wrote:

>
> On Mon, 7 May 2001, David S. Miller wrote:
> >
> > The only downside would be that the formerly "quick case" in the loop
> > of dealing with referenced pages would now need to go inside the page
> > lock. It's probably a non-issue...
>
> It might easily be an issue. That function will touch pretty much every
> single page that we ever want to free, and it might be worthwhile to know
> what the pressure is.
>
> However, the point is probably moot. I found a problem with my approach:
> using writepage() to try to get rid of swap cache pages early on (ie not
> doing the "if it is accessed, put it back on the list" thing early)
> doesn't work all that well: it doesn't handle the case of _clean_
> swap-cache pages at all. And those can be quite common, although usually
> not in the simple benchmarks which just dirty as quickly as they can.
>
> [ The way to get a clean swap-cache page is to dirty it early in the
> process lifetime, and then use the page read-only later on over
> time. Maybe it's not common enough to worry about. ]

What about swapin readahead ?