From: Tony Finch <fanf@isc.org>
Date: Fri, 3 Mar 2023 12:05:51 +0000 (+0000)
Subject: Compact more in dns_qp_compact(DNS_QPGC_ALL)
X-Git-Tag: v9.19.12~10^2~2
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=39f38754e22d048275e0cadf2ce480408c70cab7;p=thirdparty%2Fbind9.git

Compact more in dns_qp_compact(DNS_QPGC_ALL)

Commit 0858514ae8 enriched dns_qp_compact() to give callers more
control over how thoroughly the trie should be compacted.

In the DNS_QPGC_ALL case, if the trie is small it might be compacted
to a new position in the same memory chunk. In this situation it will
still be holding references to old leaf objects which have been
removed from the trie but will not be completely detached until the
chunk containing the references is freed.

This change resets the qp-trie allocator to a fresh chunk before a
DNS_QPGC_ALL compaction, so all the old memory chunks will be
evacuated and old leaf objects can be detached sooner.
---

diff --git a/lib/dns/qp.c b/lib/dns/qp.c
index bec2ef84850..881b68ec9a5 100644
--- a/lib/dns/qp.c
+++ b/lib/dns/qp.c
@@ -903,6 +903,7 @@ dns_qp_compact(dns_qp_t *qp, dns_qpgc_t mode) {
 		return;
 	}
 	if (mode == DNS_QPGC_ALL) {
+		alloc_reset(qp);
 		qp->compact_all = true;
 	}
 	compact(qp);
diff --git a/tests/bench/load-names.c b/tests/bench/load-names.c
index a1473d8694e..f7d5aa79d24 100644
--- a/tests/bench/load-names.c
+++ b/tests/bench/load-names.c
@@ -164,7 +164,7 @@ add_qp(void *qp, size_t count) {
 
 static void
 sqz_qp(void *qp) {
-	dns_qp_compact(qp, true);
+	dns_qp_compact(qp, DNS_QPGC_ALL);
 }
 
 static isc_result_t
diff --git a/tests/bench/qp-dump.c b/tests/bench/qp-dump.c
index 515048ea97f..9cf72c16616 100644
--- a/tests/bench/qp-dump.c
+++ b/tests/bench/qp-dump.c
@@ -224,7 +224,7 @@ main(int argc, char *argv[]) {
 		labels += name->labels;
 		names += 1;
 	}
-	dns_qp_compact(qp, true);
+	dns_qp_compact(qp, DNS_QPGC_ALL);
 
 	size_t smallbytes = wirebytes + labels + names * sizeof(isc_refcount_t);
 	dns_qp_memusage_t memusage = dns_qp_memusage(qp);
diff --git a/tests/bench/qpmulti.c b/tests/bench/qpmulti.c
index 59c9a11a3ef..f6150024a92 100644
--- a/tests/bench/qpmulti.c
+++ b/tests/bench/qpmulti.c
@@ -323,8 +323,12 @@ mutate_transactions(uv_idle_t *idle) {
 				args->absent++;
 			}
 		}
+		/*
+		 * We would normally use DNS_QPGC_MAYBE, but here we do the
+		 * fragmented check ourself so we can count compactions
+		 */
 		if (dns_qp_memusage(qp).fragmented) {
-			dns_qp_compact(qp, false);
+			dns_qp_compact(qp, DNS_QPGC_NOW);
 			args->compactions++;
 		}
 		dns_qpmulti_commit(args->multi, &qp);
@@ -392,7 +396,7 @@ load_multi(struct bench_state *bctx) {
 		item[i].present = true;
 		count++;
 	}
-	dns_qp_compact(qp, true);
+	dns_qp_compact(qp, DNS_QPGC_ALL);
 	dns_qpmulti_commit(bctx->multi, &qp);
 
 	bctx->load_time = isc_time_monotonic() - start;