Messages in this thread | | | Date | Thu, 22 Apr 2010 08:59:43 +0900 | From | KAMEZAWA Hiroyuki <> | Subject | Re: [PATCH 04/14] mm,migration: Allow the migration of PageSwapCache pages |
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On Wed, 21 Apr 2010 09:30:20 -0500 (CDT) Christoph Lameter <cl@linux-foundation.org> 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@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ >
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