Re: migratepage failures on reiserfs

[Chris Mason <chris.mason@oracle.com>]

On Mon, 5 Nov 2007 10:23:35 +0000
mel@skynet.ie (Mel Gorman) wrote:

> On (01/11/07 10:10), Badari Pulavarty didst pronounce:
>
> > > Hmpf, my first reply had a paragraph about the block device inode
> > > pages, I noticed the phrase file data pages and deleted it ;)
> > > 
> > > But, for the metadata buffers there's not much we can do.  They
> > > are included in a bunch of different lists and the patch would
> > > be non-trivial.
> > 
> > Unfortunately, these buffer pages are spread all around making
> > those sections of memory non-removable. Of course, one can use
> > ZONE_MOVABLE to make sure to guarantee the remove. But I am
> > hoping we could easily group all these allocations and minimize
> > spreading them around. Mel ?
> 
> The grow_dev_page() pages should be reclaimable even though migration
> is not supported for those pages? They were marked movable as it was
> useful for lumpy reclaim taking back pages for hugepage allocations
> and the like. Would it make sense for memory unremove to attempt
> migration first and reclaim second?
> 

In this case, reiserfs has the page pinned while it is doing journal
magic.  Not sure if ext3 has the same issues.

-chris