From: Vladimír Čunát <vladimir.cunat@nic.cz>
Date: Tue, 2 Jul 2019 09:22:04 +0000 (+0200)
Subject: gc: better approximation of the space to free
X-Git-Tag: v4.1.0^2~4
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a6beba003ad9189951d2aa365764e8e2fa65248e;p=thirdparty%2Fknot-resolver.git

gc: better approximation of the space to free
---

diff --git a/utils/cache_gc/kr_cache_gc.c b/utils/cache_gc/kr_cache_gc.c
index 01b01a160..e240b2920 100644
--- a/utils/cache_gc/kr_cache_gc.c
+++ b/utils/cache_gc/kr_cache_gc.c
@@ -180,7 +180,16 @@ int kr_cache_gc(kr_cache_gc_cfg_t *cfg)
 		return ret;
 	}
 
-	ssize_t amount_tofree = knot_db_lmdb_get_mapsize(db) * cfg->cache_to_be_freed / 100;
+	//ssize_t amount_tofree = knot_db_lmdb_get_mapsize(db) * cfg->cache_to_be_freed / 100;
+	// Mixing ^^ page usage and entry sizes (key+value lengths) didn't work
+	// too well, probably due to internal fragmentation after some GC cycles.
+	// Therefore let's scale this by the ratio of these two sums.
+	ssize_t cats_sumsize = 0;
+	for (int i = 0; i < CATEGORIES; ++i) {
+		cats_sumsize += cats.categories_sizes[i];
+	}
+	ssize_t amount_tofree = knot_db_lmdb_get_mapsize(db) * cfg->cache_to_be_freed
+		* cats_sumsize / (100 * knot_db_lmdb_get_usage(db));
 
 #ifdef DEBUG
 	printf("tofree: %zd\n", amount_tofree);