I've got meaning of shrinker::count_objects() wrong: it should return
number of potentially freeable objects, which is not necessary correlate
with freeable memory.
Returning 256 per THP in queue is not reasonable:
shrinker::scan_objects() never called with nr_to_scan > 128 in my setup.
Let's return 1 per THP and correct scan_object accordingly.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
---
mm/huge_memory.c | 9 ++-------
1 file changed, 2 insertions(+), 7 deletions(-)
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 769ea8db5771..36f98459f854 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -3465,12 +3465,7 @@ static unsigned long deferred_split_count(struct shrinker *shrink,
struct shrink_control *sc)
{
struct pglist_data *pgdata = NODE_DATA(sc->nid);
- /*
- * Split a page from split_queue will free up at least one page,
- * at most HPAGE_PMD_NR - 1. We don't track exact number.
- * Let's use HPAGE_PMD_NR / 2 as ballpark.
- */
- return ACCESS_ONCE(pgdata->split_queue_len) * HPAGE_PMD_NR / 2;
+ return ACCESS_ONCE(pgdata->split_queue_len);
}
static unsigned long deferred_split_scan(struct shrinker *shrink,
@@ -3511,7 +3506,7 @@ static unsigned long deferred_split_scan(struct shrinker *shrink,
list_splice_tail(&list, &pgdata->split_queue);
spin_unlock_irqrestore(&pgdata->split_queue_lock, flags);
- return split * HPAGE_PMD_NR / 2;
+ return split;
}
static struct shrinker deferred_split_shrinker = {
--
2.7.0.rc3
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