Re: [RFC][PATCH] Convert do_no_page() to a hook to avoid DFS race

Paul E. McKenney
2003-05-31T23:38:06Z

On Fri, May 30, 2003 at 06:00:27PM -0700, Andrew Morton wrote:
> "Paul E. McKenney" <paulmck@us.ibm.com> wrote:
> > There
> > is still an inlined do_no_page() wrapper due to the fact that
> > do_anonymous_page() requires that the mm->page_table_lock be
> > held on entry, while the ->nopage callouts require that this
> > lock be dropped.
>
> I sugest you change the ->nopage definition so that page_table_lock is held
> on entry to ->nopage, and ->nopage must drop it at some point. This gives
> the nopage implementations some more flexibility and may perhaps eliminate
> that special case?

Will do!

> > This patch is untested.
>
> I don't think there's a lot of point in making changes until the code which
> requires those changes is accepted into the tree. Otherwise it may be
> pointless churn, and there's nothing in-tree to exercise the new features.

A GPLed use of these DFS features is expected Real Soon Now...

Thanx, Paul