Messages in this thread | | | Date | Fri, 14 Apr 2006 11:48:09 -0700 (PDT) | From | Christoph Lameter <> | Subject | Re: Implement lookup_swap_cache for migration entries |
| |
On Fri, 14 Apr 2006, Andrew Morton wrote:
> > @@ -305,6 +306,12 @@ struct page * lookup_swap_cache(swp_entr > > { > > struct page *page; > > > > + if (is_migration_entry(entry)) { > > + page = migration_entry_to_page(entry); > > + get_page(page); > > + return page; > > + } > > What locking ensures that the state of `entry' remains unaltered across the > is_migration_entry() and migration_entry_to_page() calls?
entry is a variable passed by value to the function.
> > +/* > > + * Must use a macro for lookup_swap_cache since the functions > > + * used are only available in certain contexts. > > + */ > > +#define lookup_swap_cache(__swp) \ > > +({ struct page *p = NULL; \ > > + if (is_migration_entry(__swp)) { \ > > + p = migration_entry_to_page(__swp); \ > > + get_page(p); \ > > + } \ > > + p; \ > > +}) > > hm. Can nommu do any of this?
If page migration is off (methinks nommu may not support numa) then the fallback functions are used.
Fallback is
is_migration_entry() == 0
therefore
#define lookup_swap_cache(__swp) NULL
like before.
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |