extstore: ext_compact_under to control compaction

had a hardcoded value of "start to compact under a slew if more than 3/4ths
of pages are used", but this allows it to be set directly.

ie; "I have 100 pages but don't want to compact util almost full, and then
drop any unread"

1 files changed, 1 insertions, 1 deletions

diff --git a/storage.c b/storage.c
index f2d4263..dfb2025 100644
--- a/storage.c
+++ b/storage.c
@@ -142,7 +142,7 @@ static int storage_compact_check(void *storage, logger *l,
         return 0;
 
     // lets pick a target "wasted" value and slew.
-    if (st.pages_free > st.page_count / 4)
+    if (st.pages_free > settings.ext_compact_under)
         return 0;
 
     // the number of free pages reduces the configured frag limit