Re: [PATCH v6 12/14] mm/gup: longterm pin migration cleaup

From: Jason Gunthorpe
Date: Wed Jan 20 2021 - 08:28:57 EST

On Tue, Jan 19, 2021 at 08:43:31PM -0500, Pavel Tatashin wrote:
> When pages are longterm pinned, we must migrated them out of movable zone.
> The function that migrates them has a hidden loop with goto. The loop is
> to retry on isolation failures, and after successful migration.
> Make this code better by moving this loop to the caller.
> Signed-off-by: Pavel Tatashin <pasha.tatashin@xxxxxxxxxx>
> mm/gup.c | 88 +++++++++++++++++++++++---------------------------------
> 1 file changed, 36 insertions(+), 52 deletions(-)

This looks OK, it is better

Reviewed-by: Jason Gunthorpe <jgg@xxxxxxxxxx>

I really dislike we always have to go over the page list twice in pin

The is_pinnable_page() and LRU isolation should really be done inside
__get_user_pages_locked() as each page is added to the output list

But that is more of a larger issue than this series