On Wed, 18 Dec 2013 17:23:03 +0800 Wanpeng Li <liwanp@xxxxxxxxxxxxxxxxxx> wrote:
> >>diff --git a/mm/rmap.c b/mm/rmap.c
> >>index 55c8b8d..1e24813 100644
> >>--- a/mm/rmap.c
> >>+++ b/mm/rmap.c
> >>@@ -1347,6 +1347,7 @@ static int try_to_unmap_cluster(unsigned long cursor, unsigned int *mapcount,
> >> unsigned long end;
> >> int ret = SWAP_AGAIN;
> >> int locked_vma = 0;
> >>+ int we_locked = 0;
> >>
> >> address = (vma->vm_start + cursor) & CLUSTER_MASK;
> >> end = address + CLUSTER_SIZE;
> >>@@ -1385,9 +1386,15 @@ static int try_to_unmap_cluster(unsigned long cursor, unsigned int *mapcount,
> >> BUG_ON(!page || PageAnon(page));
> >>
> >> if (locked_vma) {
> >>- mlock_vma_page(page); /* no-op if already mlocked */
> >>- if (page == check_page)
> >>+ if (page != check_page) {
> >>+ we_locked = trylock_page(page);
> >
> >If it's not us who has the page already locked, but somebody else, he
> >might unlock it at this point and then the BUG_ON in mlock_vma_page()
> >will trigger again.
yes, this patch is pretty weak.
> Any better idea is appreciated. ;-)
Remove the BUG_ON() from mlock_vma_page()? Why was it added?
isolate_lru_page() and putback_lru_page() and *might* require
the page be locked, but I don't immediately see issues?
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