zsmalloc: partial page ordering within a fullness_list
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@kernel.org: code adjustments]
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.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/mm/zsmalloc.c b/mm/zsmalloc.c
index 27b9661..615b9b9 100644
--- a/mm/zsmalloc.c
+++ b/mm/zsmalloc.c
@@ -643,13 +643,22 @@
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;
}
/*