mm: remove the memory isolate notifier

Luckily, we have no users left, so we can get rid of it.  Cleanup
set_migratetype_isolate() a little bit.

Link: http://lkml.kernel.org/r/20191114131911.11783-2-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Qian Cai <cai@lca.pw>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Pingfan Liu <kernelfans@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 4 insertions, 34 deletions

diff --git a/mm/page_isolation.c b/mm/page_isolation.c
index 04ee1663cdbe..21af88b718aa 100644
--- a/mm/page_isolation.c
+++ b/mm/page_isolation.c
@@ -18,9 +18,7 @@
 static int set_migratetype_isolate(struct page *page, int migratetype, int isol_flags)
 {
 	struct zone *zone;
-	unsigned long flags, pfn;
-	struct memory_isolate_notify arg;
-	int notifier_ret;
+	unsigned long flags;
 	int ret = -EBUSY;
 
 	zone = page_zone(page);
@@ -35,41 +33,11 @@ static int set_migratetype_isolate(struct page *page, int migratetype, int isol_
 	if (is_migrate_isolate_page(page))
 		goto out;
 
-	pfn = page_to_pfn(page);
-	arg.start_pfn = pfn;
-	arg.nr_pages = pageblock_nr_pages;
-	arg.pages_found = 0;
-
-	/*
-	 * It may be possible to isolate a pageblock even if the
-	 * migratetype is not MIGRATE_MOVABLE. The memory isolation
-	 * notifier chain is used by balloon drivers to return the
-	 * number of pages in a range that are held by the balloon
-	 * driver to shrink memory. If all the pages are accounted for
-	 * by balloons, are free, or on the LRU, isolation can continue.
-	 * Later, for example, when memory hotplug notifier runs, these
-	 * pages reported as "can be isolated" should be isolated(freed)
-	 * by the balloon driver through the memory notifier chain.
-	 */
-	notifier_ret = memory_isolate_notify(MEM_ISOLATE_COUNT, &arg);
-	notifier_ret = notifier_to_errno(notifier_ret);
-	if (notifier_ret)
-		goto out;
 	/*
 	 * FIXME: Now, memory hotplug doesn't call shrink_slab() by itself.
 	 * We just check MOVABLE pages.
 	 */
-	if (!has_unmovable_pages(zone, page, arg.pages_found, migratetype,
-				 isol_flags))
-		ret = 0;
-
-	/*
-	 * immobile means "not-on-lru" pages. If immobile is larger than
-	 * removable-by-driver pages reported by notifier, we'll fail.
-	 */
-
-out:
-	if (!ret) {
+	if (!has_unmovable_pages(zone, page, 0, migratetype, isol_flags)) {
 		unsigned long nr_pages;
 		int mt = get_pageblock_migratetype(page);
 
@@ -79,8 +47,10 @@ out:
 									NULL);
 
 		__mod_zone_freepage_state(zone, -nr_pages, mt);
+		ret = 0;
 	}
 
+out:
 	spin_unlock_irqrestore(&zone->lock, flags);
 	if (!ret)
 		drain_all_pages(zone);