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>

diff --git a/include/linux/migrate.h b/include/linux/migrate.h
index ce42847ed35fd0f0f54bc5a4f480f58cbde03727..0b5865c61efdf704d3e0768fa0fa4910bf7a4308 100644 (file)
--- a/include/linux/migrate.h
+++ b/include/linux/migrate.h
@@ -27,6 +27,7 @@ typedef struct page *new_page_t(struct page *, unsigned long private, int **);
 #ifdef CONFIG_MIGRATION
 
 extern void putback_lru_pages(struct list_head *l);
+extern void putback_movable_pages(struct list_head *l);
 extern int migrate_page(struct address_space *,
                        struct page *, struct page *, enum migrate_mode);
 extern int migrate_pages(struct list_head *l, new_page_t x,
@@ -50,6 +51,7 @@ extern int migrate_huge_page_move_mapping(struct address_space *mapping,
 #else
 
 static inline void putback_lru_pages(struct list_head *l) {}
+static inline void putback_movable_pages(struct list_head *l) {}
 static inline int migrate_pages(struct list_head *l, new_page_t x,
                unsigned long private, bool offlining,
                enum migrate_mode mode) { return -ENOSYS; }

diff --git a/mm/compaction.c b/mm/compaction.c
index 470474c03b6123aa57876b1aac7006964aca9028..d24dd2d7bad407140c4b0e6fe514a0cb187bbcc8 100644 (file)
--- 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 427343c0c29620bc2d0c34499a799eea645263f0..3f675ca08279f27af98b4a046413be029cf082b8 100644 (file)
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -76,6 +76,26 @@ void putback_lru_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));
+                       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 +

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 5a7b7611d4e4bad1ba81d2a0541020a77063d3fd..d9fbac1b5030bd6c1333c042446e8a3260551b4f 100644 (file)
--- 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;
 }