mm: migrate: Fix page migration stalls for blkdev pages

Jan Kara
2018-12-11T17:21:51Z

Hello,

this patch set deals with page migration stalls that were reported by our
customer due to block device page that had buffer head that was in bh LRU
cache.

The patch set modifies page migration code so that buffer heads are completely
handled inside buffer_migrate_page() and then provides new migration helper
for pages with buffer heads that is safe to use even for block device pages
and that also deals with bh lrus.

Honza