http2/hpack: fix memory leak in headerFieldTable lookup maps
An earlier performance change, https://golang.org/cl/37406,
made headerFieldTable lookups O(1). The entries in the maps used to perform
these lookups were not evicted along with the original field elements, however
causing a gradual memory leak. This is most apparent when the headers have
highly variable content such as request IDs or timings.
Fixes golang/go#19756
Change-Id: Icdb51527eb671925216350ada15f2a1336ea3158
Reviewed-on: https://go-review.googlesource.com/38781
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Tom Bergan <tombergan@google.com>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
diff --git a/http2/hpack/tables.go b/http2/hpack/tables.go
index 8701592..31bd5a5 100644
--- a/http2/hpack/tables.go
+++ b/http2/hpack/tables.go
@@ -69,10 +69,10 @@
f := t.ents[k]
id := t.evictCount + uint64(k) + 1
if t.byName[f.Name] == id {
- t.byName[f.Name] = 0
+ delete(t.byName, f.Name)
}
if p := (pairNameValue{f.Name, f.Value}); t.byNameValue[p] == id {
- t.byNameValue[p] = 0
+ delete(t.byNameValue, p)
}
}
copy(t.ents, t.ents[n:])
diff --git a/http2/hpack/tables_test.go b/http2/hpack/tables_test.go
index 7f40d9a..d963f36 100644
--- a/http2/hpack/tables_test.go
+++ b/http2/hpack/tables_test.go
@@ -89,6 +89,32 @@
}
}
+func TestHeaderFieldTable_LookupMapEviction(t *testing.T) {
+ table := &headerFieldTable{}
+ table.init()
+ table.addEntry(pair("key1", "value1-1"))
+ table.addEntry(pair("key2", "value2-1"))
+ table.addEntry(pair("key1", "value1-2"))
+ table.addEntry(pair("key3", "value3-1"))
+ table.addEntry(pair("key4", "value4-1"))
+ table.addEntry(pair("key2", "value2-2"))
+
+ // evict all pairs
+ table.evictOldest(table.len())
+
+ if l := table.len(); l > 0 {
+ t.Errorf("table.len() = %d, want 0", l)
+ }
+
+ if l := len(table.byName); l > 0 {
+ t.Errorf("len(table.byName) = %d, want 0", l)
+ }
+
+ if l := len(table.byNameValue); l > 0 {
+ t.Errorf("len(table.byNameValue) = %d, want 0", l)
+ }
+}
+
func TestStaticTable(t *testing.T) {
fromSpec := `
+-------+-----------------------------+---------------+
