We want to see more ZS_FULL pages and less ZS_ALMOST_{FULL, EMPTY}
pages. Put a page with higher ->inuse count first within its
->fullness_list, which will give us better chances to fill up this
page with new objects (find_get_zspage() return ->fullness_list head
for new object allocation), so some zspages will become
ZS_ALMOST_FULL/ZS_FULL quicker.
It performs a trivial and cheap ->inuse compare which does not
slow down zsmalloc and in the worst case keeps the list pages in
no particular order.
A more expensive solution could sort fullness_list by ->inuse count.
[Minchan Kim: code adjustments]
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@xxxxxxxxx>
---
mm/zsmalloc.c | 19 ++++++++++++++-----
1 file changed, 14 insertions(+), 5 deletions(-)
diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
index 0a7f81a..3538b8c 100644
--- a/mm/zsmalloc.c
+++ b/mm/zsmalloc.c
@@ -658,13 +658,22 @@ static void insert_zspage(struct page *page, struct size_class *class,
if (fullness >= _ZS_NR_FULLNESS_GROUPS)
return;
- head = &class->fullness_list[fullness];
- if (*head)
- list_add_tail(&page->lru, &(*head)->lru);
-
- *head = page;
zs_stat_inc(class, fullness == ZS_ALMOST_EMPTY ?
CLASS_ALMOST_EMPTY : CLASS_ALMOST_FULL, 1);
+
+ head = &class->fullness_list[fullness];
+ if (!*head) {
+ *head = page;
+ return;
+ }
+
+ /*
+ * We want to see more ZS_FULL pages and less almost
+ * empty/full. Put pages with higher ->inuse first.
+ */
+ list_add_tail(&page->lru, &(*head)->lru);
+ if (page->inuse >= (*head)->inuse)
+ *head = page;
}
/*
--
2.5.0.rc0.3.g912bd49
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