page migraton: handle orphaned pages

Orphaned page might have fs-private metadata, the page is truncated.  As
the page hasn't mapping, page migration refuse to migrate the page.  It
appears the page is only freed in page reclaim and if zone watermark is
low, the page is never freed, as a result migration always fail.  I thought
we could free the metadata so such page can be freed in migration and make
migration more reliable.

[akpm@linux-foundation.org: go direct to try_to_free_buffers()]
Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Acked-by: Nick Piggin <npiggin@suse.de>
Acked-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Shaohua Li
2008-02-04 22:29:33 -08:00
committed by Linus Torvalds
parent 7786fa9ac5
commit 62e1c55300
2 changed files with 25 additions and 7 deletions

View File

@@ -84,7 +84,7 @@ EXPORT_SYMBOL(cancel_dirty_page);
/*
* If truncate cannot remove the fs-private metadata from the page, the page
* becomes anonymous. It will be left on the LRU and may even be mapped into
* becomes orphaned. It will be left on the LRU and may even be mapped into
* user pagetables if we're racing with filemap_fault().
*
* We need to bale out if page->mapping is no longer equal to the original