From: Vladimír Čunát <vladimir.cunat@nic.cz>
Date: Thu, 20 Jun 2019 12:57:52 +0000 (+0200)
Subject: utils/cache_gc: adapt for faster checking of usage
X-Git-Tag: v4.1.0^2~18
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=59a68322b32cf3436fd28d17ca296c8ab4c24922;p=thirdparty%2Fknot-resolver.git

utils/cache_gc: adapt for faster checking of usage

- don't print a line in every checking cycle
- don't exit when cache isn't found
- reduce recommended interval to 10s (compromise)
- don't increase cache size (but keep the code for now)
---

diff --git a/daemon/README.rst b/daemon/README.rst
index 8fbb5dbc5..47bb5146f 100644
--- a/daemon/README.rst
+++ b/daemon/README.rst
@@ -630,7 +630,7 @@ and configure it to run every minute, use:
 
 .. code-block:: bash
 
-   $ kres_cache_gc -c /var/cache/knot-resolver -d 60000
+   $ kres_cache_gc -c /var/cache/knot-resolver -d 10000
 
 It's also possible to run this under systemd. However, a dedicated systemd unit
 is not currently part of the upstream package. See `message#167`_ on our
diff --git a/utils/cache_gc/db.c b/utils/cache_gc/db.c
index 16f287b81..40fba149f 100644
--- a/utils/cache_gc/db.c
+++ b/utils/cache_gc/db.c
@@ -35,7 +35,7 @@ static knot_db_t *knot_db_t_kres2libknot(const knot_db_t *db)
 	return libknot_db;
 }
 
-int kr_gc_cache_open(const char *cache_path, struct kr_cache *kres_db, knot_db_t **libknot_db, double *usage)
+int kr_gc_cache_open(const char *cache_path, struct kr_cache *kres_db, knot_db_t **libknot_db)
 {
 	char cache_data[strlen(cache_path) + 10];
 	snprintf(cache_data, sizeof(cache_data), "%s/data.mdb", cache_path);
@@ -64,19 +64,6 @@ open_kr_cache:
 		return -ENOMEM;
 	}
 
-	size_t real_size = knot_db_lmdb_get_mapsize(*libknot_db), usageb = knot_db_lmdb_get_usage(*libknot_db);
-	*usage = (double)usageb / real_size * 100.0;
-	printf("Cache size: %zu, Usage: %zu (%.2lf%%)\n", real_size, usageb, *usage);
-
-#if 1
-	if (*usage > 90.0) {
-		free(*libknot_db);
-		kr_cache_close(kres_db);
-		cache_size += cache_size / 10;
-		opts.maxsize = cache_size;
-		goto open_kr_cache;
-	}
-# endif
 	return 0;
 }
 
diff --git a/utils/cache_gc/db.h b/utils/cache_gc/db.h
index 12e01ec7f..52a7ee36e 100644
--- a/utils/cache_gc/db.h
+++ b/utils/cache_gc/db.h
@@ -5,7 +5,7 @@
 
 #include "kr_cache_gc.h"
 
-int kr_gc_cache_open(const char *cache_path, struct kr_cache *kres_db, knot_db_t **libknot_db, double *usage);
+int kr_gc_cache_open(const char *cache_path, struct kr_cache *kres_db, knot_db_t **libknot_db);
 
 void kr_gc_cache_close(struct kr_cache *kres_db, knot_db_t *knot_db);
 
diff --git a/utils/cache_gc/kr_cache_gc.c b/utils/cache_gc/kr_cache_gc.c
index 9c6886b34..26a0226cc 100644
--- a/utils/cache_gc/kr_cache_gc.c
+++ b/utils/cache_gc/kr_cache_gc.c
@@ -143,14 +143,29 @@ int kr_cache_gc(kr_cache_gc_cfg_t *cfg)
 {
 	struct kr_cache kres_db = { 0 };
 	knot_db_t *db = NULL;
-	double db_usage;
 
-	int ret = kr_gc_cache_open(cfg->cache_path, &kres_db, &db, &db_usage);
+	int ret = kr_gc_cache_open(cfg->cache_path, &kres_db, &db);
 	if (ret) {
 		return ret;
 	}
 
-	if (cfg->dry_run || db_usage < cfg->cache_max_usage) {
+	const size_t db_size = knot_db_lmdb_get_mapsize(db);
+	const size_t db_usage_abs = knot_db_lmdb_get_usage(db);
+	const double db_usage = (double)db_usage_abs / db_size * 100.0;
+#if 0 // Probably not worth it, better reduce the risk by checking more often.
+	if (db_usage > 90.0) {
+		free(*libknot_db);
+		kr_cache_close(kres_db);
+		cache_size += cache_size / 10;
+		opts.maxsize = cache_size;
+		goto open_kr_cache;
+	}
+# endif
+	const bool large_usage = db_usage >= cfg->cache_max_usage;
+	if (cfg->dry_run || large_usage) { // don't print this on every size check
+		printf("Usage: %.2lf%% (%zu / %zu)\n", db_usage, db_usage_abs, db_size);
+	}
+	if (cfg->dry_run || !large_usage) {
 		kr_gc_cache_close(&kres_db, db);
 		return KNOT_EOK;
 	}
diff --git a/utils/cache_gc/main.c b/utils/cache_gc/main.c
index de5da04c3..ad249dba0 100644
--- a/utils/cache_gc/main.c
+++ b/utils/cache_gc/main.c
@@ -116,7 +116,8 @@ int main(int argc, char *argv[])
 
 	do {
 		int ret = kr_cache_gc(&cfg);
-		if (ret) {
+		// ENOENT: kresd may not be started yet or cleared the cache now
+		if (ret && ret != -ENOENT) {
 			printf("Error (%s)\n", kr_strerror(ret));
 			return 10;
 		}