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Optimise memory usage when calling /g_m_e (#1819)

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* Optimise memory usage when calling /g_m_e

* cache more events

* refactor handling of device list update pokes

* Sigh
This commit is contained in:
Kegsay 2021-04-08 13:50:39 +01:00 committed by GitHub
parent 5ade348d14
commit b769d5a25e
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GPG key ID: 4AEE18F83AFDEB23
2 changed files with 60 additions and 52 deletions
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44
federationapi/routing/send.go
View file

@ -620,7 +620,9 @@ func checkAllowedByState(e *gomatrixserverlib.Event, stateEvents []*gomatrixserv
return gomatrixserverlib.Allowed(e, &authUsingState)
}
func (t *txnReq) processEventWithMissingState(ctx context.Context, e *gomatrixserverlib.Event, roomVersion gomatrixserverlib.RoomVersion) error {
func (t *txnReq) processEventWithMissingState(
ctx context.Context, e *gomatrixserverlib.Event, roomVersion gomatrixserverlib.RoomVersion,
) error {
// Do this with a fresh context, so that we keep working even if the
// original request times out. With any luck, by the time the remote
// side retries, we'll have fetched the missing state.
@ -784,7 +786,7 @@ func (t *txnReq) lookupStateAfterEvent(ctx context.Context, roomVersion gomatrix
default:
return nil, false, fmt.Errorf("t.lookupEvent: %w", err)
}
t.haveEvents[h.EventID()] = h
t.cacheAndReturn(h)
if h.StateKey() != nil {
addedToState := false
for i := range respState.StateEvents {
@ -803,6 +805,14 @@ func (t *txnReq) lookupStateAfterEvent(ctx context.Context, roomVersion gomatrix
return respState, false, nil
}
func (t *txnReq) cacheAndReturn(ev *gomatrixserverlib.HeaderedEvent) *gomatrixserverlib.HeaderedEvent {
if cached, exists := t.haveEvents[ev.EventID()]; exists {
return cached
}
t.haveEvents[ev.EventID()] = ev
return ev
}
func (t *txnReq) lookupStateAfterEventLocally(ctx context.Context, roomID, eventID string) *gomatrixserverlib.RespState {
var res api.QueryStateAfterEventsResponse
err := t.rsAPI.QueryStateAfterEvents(ctx, &api.QueryStateAfterEventsRequest{
@ -810,15 +820,21 @@ func (t *txnReq) lookupStateAfterEventLocally(ctx context.Context, roomID, event
PrevEventIDs: []string{eventID},
}, &res)
if err != nil || !res.PrevEventsExist {
util.GetLogger(ctx).WithError(err).Warnf("failed to query state after %s locally", eventID)
util.GetLogger(ctx).WithField("room_id", roomID).WithError(err).Warnf("failed to query state after %s locally, prev exists=%v", eventID, res.PrevEventsExist)
return nil
}
stateEvents := make([]*gomatrixserverlib.HeaderedEvent, len(res.StateEvents))
for i, ev := range res.StateEvents {
t.haveEvents[ev.EventID()] = res.StateEvents[i]
// set the event from the haveEvents cache - this means we will share pointers with other prev_event branches for this
// processEvent request, which is better for memory.
stateEvents[i] = t.cacheAndReturn(ev)
}
// we should never access res.StateEvents again so we delete it here to make GC faster
res.StateEvents = nil
var authEvents []*gomatrixserverlib.Event
missingAuthEvents := map[string]bool{}
for _, ev := range res.StateEvents {
for _, ev := range stateEvents {
for _, ae := range ev.AuthEventIDs() {
if aev, ok := t.haveEvents[ae]; ok {
authEvents = append(authEvents, aev.Unwrap())
@ -843,14 +859,13 @@ func (t *txnReq) lookupStateAfterEventLocally(ctx context.Context, roomID, event
return nil
}
for i := range queryRes.Events {
evID := queryRes.Events[i].EventID()
t.haveEvents[evID] = queryRes.Events[i]
authEvents = append(authEvents, queryRes.Events[i].Unwrap())
authEvents = append(authEvents, t.cacheAndReturn(queryRes.Events[i]).Unwrap())
}
queryRes.Events = nil
}
return &gomatrixserverlib.RespState{
StateEvents: gomatrixserverlib.UnwrapEventHeaders(res.StateEvents),
StateEvents: gomatrixserverlib.UnwrapEventHeaders(stateEvents),
AuthEvents: authEvents,
}
}
@ -860,8 +875,6 @@ func (t *txnReq) lookupStateAfterEventLocally(ctx context.Context, roomID, event
func (t *txnReq) lookupStateBeforeEvent(ctx context.Context, roomVersion gomatrixserverlib.RoomVersion, roomID, eventID string) (
*gomatrixserverlib.RespState, error) {
util.GetLogger(ctx).Infof("lookupStateBeforeEvent %s", eventID)
// Attempt to fetch the missing state using /state_ids and /events
return t.lookupMissingStateViaStateIDs(ctx, roomID, eventID, roomVersion)
}
@ -992,7 +1005,6 @@ Event:
}
}
// we processed everything!
return newEvents, nil
}
@ -1011,7 +1023,7 @@ func (t *txnReq) lookupMissingStateViaState(ctx context.Context, roomID, eventID
func (t *txnReq) lookupMissingStateViaStateIDs(ctx context.Context, roomID, eventID string, roomVersion gomatrixserverlib.RoomVersion) (
*gomatrixserverlib.RespState, error) {
util.GetLogger(ctx).Infof("lookupMissingStateViaStateIDs %s", eventID)
util.GetLogger(ctx).WithField("room_id", roomID).Infof("lookupMissingStateViaStateIDs %s", eventID)
// fetch the state event IDs at the time of the event
stateIDs, err := t.federation.LookupStateIDs(ctx, t.Origin, roomID, eventID)
if err != nil {
@ -1040,14 +1052,16 @@ func (t *txnReq) lookupMissingStateViaStateIDs(ctx context.Context, roomID, even
}
for i := range queryRes.Events {
evID := queryRes.Events[i].EventID()
t.haveEvents[evID] = queryRes.Events[i]
t.cacheAndReturn(queryRes.Events[i])
if missing[evID] {
delete(missing, evID)
}
}
queryRes.Events = nil // allow it to be GCed
concurrentRequests := 8
missingCount := len(missing)
util.GetLogger(ctx).WithField("room_id", roomID).WithField("event_id", eventID).Infof("lookupMissingStateViaStateIDs missing %d/%d events", missingCount, len(wantIDs))
// If over 50% of the auth/state events from /state_ids are missing
// then we'll just call /state instead, otherwise we'll just end up
@ -1112,7 +1126,7 @@ func (t *txnReq) lookupMissingStateViaStateIDs(ctx context.Context, roomID, even
return
}
haveEventsMutex.Lock()
t.haveEvents[h.EventID()] = h
t.cacheAndReturn(h)
haveEventsMutex.Unlock()
}

68
keyserver/internal/device_list_update.go
View file

@ -72,10 +72,8 @@ func init() {
// we guarantee we will get around to it. Also, more users on a given server does not increase the number of requests
// (as /keys/query allows multiple users to be specified) so being stuck behind matrix.org won't materially be any worse
// than being stuck behind foo.bar
// In the event that the query fails, the worker spins up a short-lived goroutine whose sole purpose is to inject the server
// name back into the channel after a certain amount of time. If in the interim the device lists have been updated, then
// the database query will return no stale lists. Reinjection into the channel continues until success or the server terminates,
// when it will be reloaded on startup.
// In the event that the query fails, a lock is acquired and the server name along with the time to wait before retrying is
// set in a map. A restarter goroutine periodically probes this map and injects servers which are ready to be retried.
type DeviceListUpdater struct {
// A map from user_id to a mutex. Used when we are missing prev IDs so we don't make more than 1
// request to the remote server and race.
@ -297,42 +295,38 @@ func (u *DeviceListUpdater) clearChannel(userID string) {
}
func (u *DeviceListUpdater) worker(ch chan gomatrixserverlib.ServerName) {
// It's possible to get many of the same server name in the channel, so in order
// to prevent processing the same server over and over we keep track of when we
// last made a request to the server. If we get the server name during the cooloff
// period, we'll ignore the poke.
lastProcessed := make(map[gomatrixserverlib.ServerName]time.Time)
// this can't be too long else sytest will give up trying to do a test
cooloffPeriod := 500 * time.Millisecond
shouldProcess := func(srv gomatrixserverlib.ServerName) bool {
// we should process requests when now is after the last process time + cooloff
return time.Now().After(lastProcessed[srv].Add(cooloffPeriod))
}
// on failure, spin up a short-lived goroutine to inject the server name again.
scheduledRetries := make(map[gomatrixserverlib.ServerName]time.Time)
inject := func(srv gomatrixserverlib.ServerName, duration time.Duration) {
time.Sleep(duration)
ch <- srv
}
for serverName := range ch {
if !shouldProcess(serverName) {
if time.Now().Before(scheduledRetries[serverName]) {
// do not inject into the channel as we know there will be a sleeping goroutine
// which will do it after the cooloff period expires
continue
} else {
scheduledRetries[serverName] = time.Now().Add(cooloffPeriod)
go inject(serverName, cooloffPeriod)
continue
retries := make(map[gomatrixserverlib.ServerName]time.Time)
retriesMu := &sync.Mutex{}
// restarter goroutine which will inject failed servers into ch when it is time
go func() {
for {
var serversToRetry []gomatrixserverlib.ServerName
time.Sleep(time.Second)
retriesMu.Lock()
now := time.Now()
for srv, retryAt := range retries {
if now.After(retryAt) {
serversToRetry = append(serversToRetry, srv)
}
}
for _, srv := range serversToRetry {
delete(retries, srv)
}
retriesMu.Unlock()
for _, srv := range serversToRetry {
ch <- srv
}
}
lastProcessed[serverName] = time.Now()
}()
for serverName := range ch {
waitTime, shouldRetry := u.processServer(serverName)
if shouldRetry {
scheduledRetries[serverName] = time.Now().Add(waitTime)
go inject(serverName, waitTime)
retriesMu.Lock()
_, exists := retries[serverName]
if !exists {
retries[serverName] = time.Now().Add(waitTime)
}
retriesMu.Unlock()
}
}
}
@ -380,7 +374,7 @@ func (u *DeviceListUpdater) processServer(serverName gomatrixserverlib.ServerNam
}
}
if failCount > 0 {
logger.WithField("total", len(userIDs)).WithField("failed", failCount).Error("failed to query device keys for some users")
logger.WithField("total", len(userIDs)).WithField("failed", failCount).WithField("wait", waitTime).Error("failed to query device keys for some users")
}
for _, userID := range userIDs {
// always clear the channel to unblock Update calls regardless of success/failure