2012/7/28 Christoph Lameter [off-list ref]:

On Sat, 28 Jul 2012, Joonsoo Kim wrote:

quoted

move_pages() syscall may return success in case that
do_move_page_to_node_array return positive value which means migration failed.

Nope. It only means that the migration for some pages has failed. This may
still be considered successful for the app if it moves 10000 pages and one
failed.

This patch would break the move_pages() syscall because an error code
return from do_move_pages_to_node_array() will cause the status byte for
each page move to not be updated anymore. Application will not be able to
tell anymore which pages were successfully moved and which are not.

In case of returning non-zero, valid status is not required according
to man page.
So, this patch would not break the move_pages() syscall.
But, I agree that returning positive value only means that the
migration for some pages has failed.
This is my mistake, so please drop this patch.
Thanks for review.

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