mm: introduce putback_movable_pages()

The PATCH "mm: introduce compaction and migration for virtio ballooned pages"
hacks around putback_lru_pages() in order to allow ballooned pages to be
re-inserted on balloon page list as if a ballooned page was like a LRU page.

As ballooned pages are not legitimate LRU pages, this patch introduces
putback_movable_pages() to properly cope with cases where the isolated
pageset contains ballooned pages and LRU pages, thus fixing the mentioned
inelegant hack around putback_lru_pages().

Signed-off-by: Rafael Aquini <aquini@redhat.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

3 files changed, 24 insertions, 4 deletions

diff --git a/mm/compaction.c b/mm/compaction.c
index 470474c03b61..d24dd2d7bad4 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -1003,7 +1003,7 @@ static int compact_zone(struct zone *zone, struct compact_control *cc)
                 switch (isolate_migratepages(zone, cc)) {
                 case ISOLATE_ABORT:
                         ret = COMPACT_PARTIAL;
-                        putback_lru_pages(&cc->migratepages);
+                        putback_movable_pages(&cc->migratepages);
                         cc->nr_migratepages = 0;
                         goto out;
                 case ISOLATE_NONE:
@@ -1026,9 +1026,9 @@ static int compact_zone(struct zone *zone, struct compact_control *cc)
                 trace_mm_compaction_migratepages(nr_migrate - nr_remaining,
                                                 nr_remaining);
 
-                /* Release LRU pages not migrated */
+                /* Release isolated pages not migrated */
                 if (err) {
-                        putback_lru_pages(&cc->migratepages);
+                        putback_movable_pages(&cc->migratepages);
                         cc->nr_migratepages = 0;
                         if (err == -ENOMEM) {
                                 ret = COMPACT_PARTIAL;
diff --git a/mm/migrate.c b/mm/migrate.c
index 427343c0c296..3f675ca08279 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -80,6 +80,26 @@ void putback_lru_pages(struct list_head *l)
                 list_del(&page->lru);
                 dec_zone_page_state(page, NR_ISOLATED_ANON +
                                 page_is_file_cache(page));
+                        putback_lru_page(page);
+        }
+}
+
+/*
+ * Put previously isolated pages back onto the appropriate lists
+ * from where they were once taken off for compaction/migration.
+ *
+ * This function shall be used instead of putback_lru_pages(),
+ * whenever the isolated pageset has been built by isolate_migratepages_range()
+ */
+void putback_movable_pages(struct list_head *l)
+{
+        struct page *page;
+        struct page *page2;
+
+        list_for_each_entry_safe(page, page2, l, lru) {
+                list_del(&page->lru);
+                dec_zone_page_state(page, NR_ISOLATED_ANON +
+                                page_is_file_cache(page));
                 if (unlikely(balloon_page_movable(page)))
                         balloon_page_putback(page);
                 else
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 5a7b7611d4e4..d9fbac1b5030 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -5761,7 +5761,7 @@ static int __alloc_contig_migrate_range(struct compact_control *cc,
                                     0, false, MIGRATE_SYNC);
         }
 
-        putback_lru_pages(&cc->migratepages);
+        putback_movable_pages(&cc->migratepages);
         return ret > 0 ? 0 : ret;
 }