xenpaging: implement stack of free slots in pagefile

Scanning the slot_to_gfn[] array for a free slot is expensive because
evict_pages() always needs to scan the whole array. Remember the last
slots freed during page-in requests and reuse them in evict_pages().

Signed-off-by: Olaf Hering <olaf@aepfle.de>
Committed-by: Ian Jackson <ian.jackson.citrix.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/tools/xenpaging/xenpaging.h b/tools/xenpaging/xenpaging.h
index 746556b1a0..e348db63c5 100644
--- a/tools/xenpaging/xenpaging.h
+++ b/tools/xenpaging/xenpaging.h
@@ -60,6 +60,8 @@ struct xenpaging {
     int policy_mru_size;
     int use_poll_timeout;
     int debug;
+    int stack_count;
+    int *free_slot_stack;
     unsigned long pagein_queue[XENPAGING_PAGEIN_QUEUE_SIZE];
 };