On Mon, 9 Dec 2013, Joonsoo Kim wrote: > First, we don't use error number in fail case. Call-path related to > new_page_node() is shown in the following. > > do_move_page_to_node_array() -> migrate_pages() -> unmap_and_move() > -> new_page_node() > > If unmap_and_move() failed, migrate_pages() also returns err, and then > do_move_page_to_node_array() skips to set page's status to user buffer. > So we don't need to set error number to each pages on failure case. I dont get this. new_page_node() sets the error condition in the page_to_node array before this patch. There is no post processing in do_move_page_to_node_array(). The function simply returns and relies on new_page_node() to have set the page status. do_move_pages() then returns the page status back to userspace. How does the change preserve these diagnostics? > Next, we don't need to set node id of the new page in unmap_and_move(), > since it cannot be different with pm->node. In new_page_node(), we always > try to allocate the page in exact node by referencing pm->node. So it is > sufficient to set node id of the new page in new_page_node(), instead of > unmap_and_move(). Thats a good thought. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>