On Wed, 21 Apr 2010 09:30:20 -0500 (CDT)
Christoph Lameter <cl@xxxxxxxxxxxxxxxxxxxx> wrote:
> On Tue, 20 Apr 2010, Mel Gorman wrote:
>
> > @@ -520,10 +521,12 @@ static int move_to_new_page(struct page *newpage, struct page *page)
> > else
> > rc = fallback_migrate_page(mapping, newpage, page);
> >
> > - if (!rc)
> > - remove_migration_ptes(page, newpage);
> > - else
> > + if (rc) {
> > newpage->mapping = NULL;
> > + } else {
> > + if (remap_swapcache)
> > + remove_migration_ptes(page, newpage);
> > + }
>
> You are going to keep the migration ptes after the page has been unlocked?
> Or is remap_swapcache true if its not a swapcache page?
>
> Maybe you meant
>
> if (!remap_swapcache)
>
Ah....Can I confirm my understanding ?
remap_swapcache == true only when
The old page was ANON && it is not mapped. && it is SwapCache.
We do above check under lock_page(). So, this SwapCache is never mapped until
we release lock_page() on the old page. So, we don't use migration_pte in
this case because try_to_unmap() do nothing and don't need to call
remove_migration_pte().
If migration_pte is used somewhere...I think it's bug.
-Kame
> ?
>
> > unlock_page(newpage);
> >
>
> >
> > skip_unmap:
> > if (!page_mapped(page))
> > - rc = move_to_new_page(newpage, page);
> > + rc = move_to_new_page(newpage, page, remap_swapcache);
> >
> > - if (rc)
> > + if (rc && remap_swapcache)
> > remove_migration_ptes(page, page);
> > rcu_unlock:
> >
>
> Looks like you meant !remap_swapcache
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@xxxxxxxxxxxxxxx
> More majordomo info at http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at http://www.tux.org/lkml/
>
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@xxxxxxxxxx For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>