__count_immobile_pages naming is rather awkward.
This patch clean up the function and add comment.
Cc: Mel Gorman <mgorman@xxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxx>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
Signed-off-by: Minchan Kim <minchan@xxxxxxxxxx>
---
mm/page_alloc.c | 33 +++++++++++++++++----------------
1 file changed, 17 insertions(+), 16 deletions(-)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 019c4fe..2c71ac9 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -5467,26 +5467,27 @@ void set_pageblock_flags_group(struct page *page, unsigned long flags,
}
/*
- * This is designed as sub function...plz see page_isolation.c also.
- * set/clear page block's type to be ISOLATE.
- * page allocater never alloc memory from ISOLATE block.
+ * This function checks whether pageblock includes unmovable pages or not.
+ * If @count is not zero, it is okay to include less @count unmovable pages
+ *
+ * This function can race in PageLRU and MIGRATE_MOVABLE can have unmovable
+ * pages so that it might be not exact.
*/
-
-static int
-__count_immobile_pages(struct zone *zone, struct page *page, int count)
+static bool
+__has_unmovable_pages(struct zone *zone, struct page *page, int count)
{
unsigned long pfn, iter, found;
int mt;
/*
* For avoiding noise data, lru_add_drain_all() should be called
- * If ZONE_MOVABLE, the zone never contains immobile pages
+ * If ZONE_MOVABLE, the zone never contains unmovable pages
*/
if (zone_idx(zone) == ZONE_MOVABLE)
- return true;
+ return false;
mt = get_pageblock_migratetype(page);
if (mt == MIGRATE_MOVABLE || is_migrate_cma(mt))
- return true;
+ return false;
pfn = page_to_pfn(page);
for (found = 0, iter = 0; iter < pageblock_nr_pages; iter++) {
@@ -5521,9 +5522,9 @@ __count_immobile_pages(struct zone *zone, struct page *page, int count)
* page at boot.
*/
if (found > count)
- return false;
+ return true;
}
- return true;
+ return false;
}
bool is_pageblock_removable_nolock(struct page *page)
@@ -5547,7 +5548,7 @@ bool is_pageblock_removable_nolock(struct page *page)
zone->zone_start_pfn + zone->spanned_pages <= pfn)
return false;
- return __count_immobile_pages(zone, page, 0);
+ return !__has_unmovable_pages(zone, page, 0);
}
int set_migratetype_isolate(struct page *page)
@@ -5586,12 +5587,12 @@ int set_migratetype_isolate(struct page *page)
* FIXME: Now, memory hotplug doesn't call shrink_slab() by itself.
* We just check MOVABLE pages.
*/
- if (__count_immobile_pages(zone, page, arg.pages_found))
+ if (!__has_unmovable_pages(zone, page, arg.pages_found))
ret = 0;
-
/*
- * immobile means "not-on-lru" paes. If immobile is larger than
- * removable-by-driver pages reported by notifier, we'll fail.
+ * Unmovable means "not-on-lru" pages. If Unmovable pages are
+ * larger than removable-by-driver pages reported by notifier,
+ * we'll fail.
*/
out:
--
1.7.9.5
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