diff --git a/src/shrpx.cc b/src/shrpx.cc
index a9f34b4..d6ec702 100644
--- a/src/shrpx.cc
+++ b/src/shrpx.cc
@@ -105,10 +105,12 @@ int cache_downstream_host_address()
   rv = getnameinfo(res->ai_addr, res->ai_addrlen, host, sizeof(host),
                   0, 0, NI_NUMERICHOST);
   if(rv == 0) {
-    LOG(INFO) << "Using first returned address for downstream "
-              << host
-              << ", port "
-              << get_config()->downstream_port;
+    if(LOG_ENABLED(INFO)) {
+      LOG(INFO) << "Using first returned address for downstream "
+                << host
+                << ", port "
+                << get_config()->downstream_port;
+    }
   } else {
     LOG(FATAL) << gai_strerror(rv);
     DIE();
@@ -147,9 +149,11 @@ evconnlistener* create_evlistener(ListenHandler *handler, int family)
   addrinfo *res, *rp;
   r = getaddrinfo(get_config()->host, service, &hints, &res);
   if(r != 0) {
-    LOG(INFO) << "Unable to get IPv" << (family == AF_INET ? "4" : "6")
-              << " address for " << get_config()->host << ": "
-               << gai_strerror(r);
+    if(LOG_ENABLED(INFO)) {
+      LOG(INFO) << "Unable to get IPv" << (family == AF_INET ? "4" : "6")
+                << " address for " << get_config()->host << ": "
+                << gai_strerror(r);
+    }
     return NULL;
   }
   for(rp = res; rp; rp = rp->ai_next) {
@@ -183,7 +187,10 @@ evconnlistener* create_evlistener(ListenHandler *handler, int family)
     r = getnameinfo(rp->ai_addr, rp->ai_addrlen, host, sizeof(host),
                         0, 0, NI_NUMERICHOST);
     if(r == 0) {
-      LOG(INFO) << "Listening on " << host << ", port " << get_config()->port;
+      if(LOG_ENABLED(INFO)) {
+        LOG(INFO) << "Listening on " << host << ", port "
+                  << get_config()->port;
+      }
     } else {
       LOG(FATAL) << gai_strerror(r);
       DIE();
@@ -191,7 +198,7 @@ evconnlistener* create_evlistener(ListenHandler *handler, int family)
   }
   freeaddrinfo(res);
   if(rp == 0) {
-    if(ENABLE_LOG) {
+    if(LOG_ENABLED(INFO)) {
       LOG(INFO) << "Listening " << (family == AF_INET ? "IPv4" : "IPv6")
                 << " socket failed";
     }
@@ -263,7 +270,7 @@ int event_loop()
     listener_handler->create_spdy_session();
   }
 
-  if(ENABLE_LOG) {
+  if(LOG_ENABLED(INFO)) {
     LOG(INFO) << "Entering event loop";
   }
   event_base_loop(evbase, 0);
diff --git a/src/shrpx_client_handler.cc b/src/shrpx_client_handler.cc
index 48620c4..fa5ae7a 100644
--- a/src/shrpx_client_handler.cc
+++ b/src/shrpx_client_handler.cc
@@ -76,13 +76,13 @@ void upstream_eventcb(bufferevent *bev, short events, void *arg)
   ClientHandler *handler = reinterpret_cast<ClientHandler*>(arg);
   bool finish = false;
   if(events & BEV_EVENT_EOF) {
-    if(ENABLE_LOG) {
+    if(LOG_ENABLED(INFO)) {
       CLOG(INFO, handler) << "EOF";
     }
     finish = true;
   }
   if(events & BEV_EVENT_ERROR) {
-    if(ENABLE_LOG) {
+    if(LOG_ENABLED(INFO)) {
       CLOG(INFO, handler) << "Network error: "
                           << evutil_socket_error_to_string
         (EVUTIL_SOCKET_ERROR());
@@ -90,7 +90,7 @@ void upstream_eventcb(bufferevent *bev, short events, void *arg)
     finish = true;
   }
   if(events & BEV_EVENT_TIMEOUT) {
-    if(ENABLE_LOG) {
+    if(LOG_ENABLED(INFO)) {
       CLOG(INFO, handler) << "Time out";
     }
     finish = true;
@@ -99,12 +99,12 @@ void upstream_eventcb(bufferevent *bev, short events, void *arg)
     delete handler;
   } else {
     if(events & BEV_EVENT_CONNECTED) {
-      if(ENABLE_LOG) {
+      if(LOG_ENABLED(INFO)) {
         CLOG(INFO, handler) << "SSL/TLS handleshake completed";
       }
       handler->set_bev_cb(upstream_readcb, upstream_writecb, upstream_eventcb);
       handler->validate_next_proto();
-      if(ENABLE_LOG) {
+      if(LOG_ENABLED(INFO)) {
         if(SSL_session_reused(handler->get_ssl())) {
           CLOG(INFO, handler) << "SSL/TLS session reused";
         }
@@ -143,7 +143,7 @@ ClientHandler::ClientHandler(bufferevent *bev, int fd, SSL *ssl,
 
 ClientHandler::~ClientHandler()
 {
-  if(ENABLE_LOG) {
+  if(LOG_ENABLED(INFO)) {
     CLOG(INFO, this) << "Deleting";
   }
   if(ssl_) {
@@ -161,7 +161,7 @@ ClientHandler::~ClientHandler()
       i != dconn_pool_.end(); ++i) {
     delete *i;
   }
-  if(ENABLE_LOG) {
+  if(LOG_ENABLED(INFO)) {
     CLOG(INFO, this) << "Deleted";
   }
 }
@@ -200,7 +200,7 @@ int ClientHandler::validate_next_proto()
   unsigned int next_proto_len;
   SSL_get0_next_proto_negotiated(ssl_, &next_proto, &next_proto_len);
   if(next_proto) {
-    if(ENABLE_LOG) {
+    if(LOG_ENABLED(INFO)) {
       std::string proto(next_proto, next_proto+next_proto_len);
       CLOG(INFO, this) << "The negotiated next protocol: " << proto;
     }
@@ -211,11 +211,11 @@ int ClientHandler::validate_next_proto()
       return 0;
     }
   } else {
-    if(ENABLE_LOG) {
+    if(LOG_ENABLED(INFO)) {
       CLOG(INFO, this) << "No proto negotiated.";
     }
   }
-  if(ENABLE_LOG) {
+  if(LOG_ENABLED(INFO)) {
     CLOG(INFO, this) << "Use HTTP/1.1";
   }
   HttpsUpstream *https_upstream = new HttpsUpstream(this);
@@ -250,7 +250,7 @@ void ClientHandler::set_should_close_after_write(bool f)
 
 void ClientHandler::pool_downstream_connection(DownstreamConnection *dconn)
 {
-  if(ENABLE_LOG) {
+  if(LOG_ENABLED(INFO)) {
     CLOG(INFO, this) << "Pooling downstream connection DCONN:" << dconn;
   }
   dconn_pool_.insert(dconn);
@@ -258,7 +258,7 @@ void ClientHandler::pool_downstream_connection(DownstreamConnection *dconn)
 
 void ClientHandler::remove_downstream_connection(DownstreamConnection *dconn)
 {
-  if(ENABLE_LOG) {
+  if(LOG_ENABLED(INFO)) {
     CLOG(INFO, this) << "Removing downstream connection DCONN:" << dconn
                      << " from pool";
   }
@@ -268,7 +268,7 @@ void ClientHandler::remove_downstream_connection(DownstreamConnection *dconn)
 DownstreamConnection* ClientHandler::get_downstream_connection()
 {
   if(dconn_pool_.empty()) {
-    if(ENABLE_LOG) {
+    if(LOG_ENABLED(INFO)) {
       CLOG(INFO, this) << "Downstream connection pool is empty."
                        << " Create new one";
     }
@@ -280,7 +280,7 @@ DownstreamConnection* ClientHandler::get_downstream_connection()
   } else {
     DownstreamConnection *dconn = *dconn_pool_.begin();
     dconn_pool_.erase(dconn);
-    if(ENABLE_LOG) {
+    if(LOG_ENABLED(INFO)) {
       CLOG(INFO, this) << "Reuse downstream connection DCONN:" << dconn
                        << " from pool";
     }
diff --git a/src/shrpx_downstream.cc b/src/shrpx_downstream.cc
index 1d89579..930b9f9 100644
--- a/src/shrpx_downstream.cc
+++ b/src/shrpx_downstream.cc
@@ -63,7 +63,7 @@ Downstream::Downstream(Upstream *upstream, int stream_id, int priority)
 
 Downstream::~Downstream()
 {
-  if(ENABLE_LOG) {
+  if(LOG_ENABLED(INFO)) {
     DLOG(INFO, this) << "Deleting";
   }
   if(response_body_buf_) {
@@ -73,7 +73,7 @@ Downstream::~Downstream()
   if(dconn_) {
     delete dconn_;
   }
-  if(ENABLE_LOG) {
+  if(LOG_ENABLED(INFO)) {
     DLOG(INFO, this) << "Deleted";
   }
 }
diff --git a/src/shrpx_http_downstream_connection.cc b/src/shrpx_http_downstream_connection.cc
index 09cbce3..de93b9c 100644
--- a/src/shrpx_http_downstream_connection.cc
+++ b/src/shrpx_http_downstream_connection.cc
@@ -66,7 +66,7 @@ HttpDownstreamConnection::~HttpDownstreamConnection()
 
 int HttpDownstreamConnection::attach_downstream(Downstream *downstream)
 {
-  if(ENABLE_LOG) {
+  if(LOG_ENABLED(INFO)) {
     DCLOG(INFO, this) << "Attaching to DOWNSTREAM:" << downstream;
   }
   Upstream *upstream = downstream->get_upstream();
@@ -85,7 +85,7 @@ int HttpDownstreamConnection::attach_downstream(Downstream *downstream)
       bev_ = 0;
       return SHRPX_ERR_NETWORK;
     }
-    if(ENABLE_LOG) {
+    if(LOG_ENABLED(INFO)) {
       DCLOG(INFO, this) << "Connecting to downstream server";
     }
   }
@@ -184,7 +184,7 @@ int HttpDownstreamConnection::push_request_headers()
   }
 
   hdrs += "\r\n";
-  if(ENABLE_LOG) {
+  if(LOG_ENABLED(INFO)) {
     const char *hdrp;
     std::string nhdrs;
     if(get_config()->tty) {
@@ -272,21 +272,21 @@ void idle_eventcb(bufferevent *bev, short events, void *arg)
   if(events & BEV_EVENT_CONNECTED) {
     // Downstream was detached before connection established?
     // This may be safe to be left.
-    if(ENABLE_LOG) {
+    if(LOG_ENABLED(INFO)) {
       DCLOG(INFO, dconn) << "Idle connection connected?";
     }
     return;
   }
   if(events & BEV_EVENT_EOF) {
-    if(ENABLE_LOG) {
+    if(LOG_ENABLED(INFO)) {
       DCLOG(INFO, dconn) << "Idle connection EOF";
     }
   } else if(events & BEV_EVENT_TIMEOUT) {
-    if(ENABLE_LOG) {
+    if(LOG_ENABLED(INFO)) {
       DCLOG(INFO, dconn) << "Idle connection timeout";
     }
   } else if(events & BEV_EVENT_ERROR) {
-    if(ENABLE_LOG) {
+    if(LOG_ENABLED(INFO)) {
       DCLOG(INFO, dconn) << "Idle connection network error";
     }
   }
@@ -298,7 +298,7 @@ void idle_eventcb(bufferevent *bev, short events, void *arg)
 
 void HttpDownstreamConnection::detach_downstream(Downstream *downstream)
 {
-  if(ENABLE_LOG) {
+  if(LOG_ENABLED(INFO)) {
     DCLOG(INFO, this) << "Detaching from DOWNSTREAM:" << downstream;
   }
   downstream->set_downstream_connection(0);
@@ -443,7 +443,7 @@ int HttpDownstreamConnection::on_read()
   if(htperr == HPE_OK) {
     return 0;
   } else {
-    if(ENABLE_LOG) {
+    if(LOG_ENABLED(INFO)) {
       DCLOG(INFO, this) << "HTTP parser failure: "
                         << "(" << http_errno_name(htperr) << ") "
                         << http_errno_description(htperr);
diff --git a/src/shrpx_https_upstream.cc b/src/shrpx_https_upstream.cc
index a5bb6ec..868eb5c 100644
--- a/src/shrpx_https_upstream.cc
+++ b/src/shrpx_https_upstream.cc
@@ -74,7 +74,7 @@ int htp_msg_begin(http_parser *htp)
 {
   HttpsUpstream *upstream;
   upstream = reinterpret_cast<HttpsUpstream*>(htp->data);
-  if(ENABLE_LOG) {
+  if(LOG_ENABLED(INFO)) {
     ULOG(INFO, upstream) << "HTTP request started";
   }
   upstream->reset_current_header_length();
@@ -131,7 +131,7 @@ int htp_hdrs_completecb(http_parser *htp)
   int rv;
   HttpsUpstream *upstream;
   upstream = reinterpret_cast<HttpsUpstream*>(htp->data);
-  if(ENABLE_LOG) {
+  if(LOG_ENABLED(INFO)) {
     ULOG(INFO, upstream) << "HTTP request headers completed";
   }
   Downstream *downstream = upstream->get_downstream();
@@ -142,7 +142,7 @@ int htp_hdrs_completecb(http_parser *htp)
 
   downstream->set_request_connection_close(!http_should_keep_alive(htp));
 
-  if(ENABLE_LOG) {
+  if(LOG_ENABLED(INFO)) {
     std::stringstream ss;
     ss << downstream->get_request_method() << " "
        << downstream->get_request_path() << " "
@@ -222,7 +222,7 @@ int htp_msg_completecb(http_parser *htp)
   int rv;
   HttpsUpstream *upstream;
   upstream = reinterpret_cast<HttpsUpstream*>(htp->data);
-  if(ENABLE_LOG) {
+  if(LOG_ENABLED(INFO)) {
     ULOG(INFO, upstream) << "HTTP request completed";
   }
   Downstream *downstream = upstream->get_downstream();
@@ -306,14 +306,14 @@ int HttpsUpstream::on_read()
           return -1;
         }
       } else if(downstream->get_output_buffer_full()) {
-        if(ENABLE_LOG) {
+        if(LOG_ENABLED(INFO)) {
           ULOG(INFO, this) << "Downstream output buffer is full";
         }
         pause_read(SHRPX_NO_BUFFER);
       }
     }
   } else {
-    if(ENABLE_LOG) {
+    if(LOG_ENABLED(INFO)) {
       ULOG(INFO, this) << "HTTP parse failure: "
                        << "(" << http_errno_name(htperr) << ") "
                        << http_errno_description(htperr);
@@ -454,16 +454,16 @@ void https_downstream_eventcb(bufferevent *bev, short events, void *ptr)
   HttpsUpstream *upstream;
   upstream = static_cast<HttpsUpstream*>(downstream->get_upstream());
   if(events & BEV_EVENT_CONNECTED) {
-    if(ENABLE_LOG) {
+    if(LOG_ENABLED(INFO)) {
       DCLOG(INFO, dconn) << "Connection established";
     }
   } else if(events & BEV_EVENT_EOF) {
-    if(ENABLE_LOG) {
+    if(LOG_ENABLED(INFO)) {
       DCLOG(INFO, dconn) << "EOF";
     }
     if(downstream->get_response_state() == Downstream::HEADER_COMPLETE) {
       // Server may indicate the end of the request by EOF
-      if(ENABLE_LOG) {
+      if(LOG_ENABLED(INFO)) {
         DCLOG(INFO, dconn) << "The end of the response body was indicated by "
                            << "EOF";
       }
@@ -483,7 +483,7 @@ void https_downstream_eventcb(bufferevent *bev, short events, void *ptr)
       // Nothing to do
     } else {
       // error
-      if(ENABLE_LOG) {
+      if(LOG_ENABLED(INFO)) {
         DCLOG(INFO, dconn) << "Treated as error";
       }
       if(upstream->error_reply(502) != 0) {
@@ -496,7 +496,7 @@ void https_downstream_eventcb(bufferevent *bev, short events, void *ptr)
       upstream->resume_read(SHRPX_MSG_BLOCK);
     }
   } else if(events & (BEV_EVENT_ERROR | BEV_EVENT_TIMEOUT)) {
-    if(ENABLE_LOG) {
+    if(LOG_ENABLED(INFO)) {
       if(events & BEV_EVENT_ERROR) {
         DCLOG(INFO, dconn) << "Network error";
       } else {
@@ -590,7 +590,7 @@ Downstream* HttpsUpstream::get_downstream() const
 
 int HttpsUpstream::on_downstream_header_complete(Downstream *downstream)
 {
-  if(ENABLE_LOG) {
+  if(LOG_ENABLED(INFO)) {
     DLOG(INFO, downstream) << "HTTP response header completed";
   }
   std::string via_value;
@@ -643,7 +643,7 @@ int HttpsUpstream::on_downstream_header_complete(Downstream *downstream)
   }
 
   hdrs += "\r\n";
-  if(ENABLE_LOG) {
+  if(LOG_ENABLED(INFO)) {
     const char *hdrp;
     std::string nhdrs;
     if(get_config()->tty) {
@@ -696,7 +696,7 @@ int HttpsUpstream::on_downstream_body_complete(Downstream *downstream)
       return -1;
     }
   }
-  if(ENABLE_LOG) {
+  if(LOG_ENABLED(INFO)) {
     DLOG(INFO, downstream) << "HTTP response completed";
   }
   if(downstream->get_request_connection_close() ||
diff --git a/src/shrpx_listen_handler.cc b/src/shrpx_listen_handler.cc
index 8cbfc53..3b9aa5a 100644
--- a/src/shrpx_listen_handler.cc
+++ b/src/shrpx_listen_handler.cc
@@ -81,7 +81,7 @@ void ListenHandler::create_worker_thread(size_t num)
     bufferevent *bev = bufferevent_socket_new(evbase_, info->sv[0],
                                               BEV_OPT_DEFER_CALLBACKS);
     info->bev = bev;
-    if(ENABLE_LOG) {
+    if(LOG_ENABLED(INFO)) {
       LLOG(INFO, this) << "Created thread #" << num_worker_;
     }
     ++num_worker_;
@@ -91,7 +91,7 @@ void ListenHandler::create_worker_thread(size_t num)
 int ListenHandler::accept_connection(evutil_socket_t fd,
                                      sockaddr *addr, int addrlen)
 {
-  if(ENABLE_LOG) {
+  if(LOG_ENABLED(INFO)) {
     LLOG(INFO, this) << "Accepted connection. fd=" << fd;
   }
   if(num_worker_ == 0) {
diff --git a/src/shrpx_log.cc b/src/shrpx_log.cc
index b9961fc..2f9bb8b 100644
--- a/src/shrpx_log.cc
+++ b/src/shrpx_log.cc
@@ -90,7 +90,7 @@ Log::Log(int severity, const char *filename, int linenum)
 
 Log::~Log()
 {
-  if(severity_ >= severity_thres_) {
+  if(log_enabled(severity_)) {
     fprintf(stderr, "[%s%s%s] %s\n       %s(%s:%d)%s\n",
             get_config()->tty ? SEVERITY_COLOR[severity_] : "",
             SEVERITY_STR[severity_],
diff --git a/src/shrpx_log.h b/src/shrpx_log.h
index b8943ef..cb1abf9 100644
--- a/src/shrpx_log.h
+++ b/src/shrpx_log.h
@@ -33,6 +33,8 @@ namespace shrpx {
 
 #define ENABLE_LOG 1
 
+#define LOG_ENABLED(SEVERITY) (ENABLE_LOG && Log::log_enabled(SEVERITY))
+
 #define LOG(SEVERITY) Log(SEVERITY, __FILE__, __LINE__)
 
 // Listener log
@@ -81,6 +83,10 @@ public:
   }
   static void set_severity_level(int severity);
   static int set_severity_level_by_name(const char *name);
+  static bool log_enabled(int severity)
+  {
+    return severity >= severity_thres_;
+  }
 private:
   int severity_;
   const char *filename_;
diff --git a/src/shrpx_spdy_downstream_connection.cc b/src/shrpx_spdy_downstream_connection.cc
index 4f400c5..22aa1c6 100644
--- a/src/shrpx_spdy_downstream_connection.cc
+++ b/src/shrpx_spdy_downstream_connection.cc
@@ -89,7 +89,7 @@ int SpdyDownstreamConnection::init_request_body_buf()
 
 int SpdyDownstreamConnection::attach_downstream(Downstream *downstream)
 {
-  if(ENABLE_LOG) {
+  if(LOG_ENABLED(INFO)) {
     DCLOG(INFO, this) << "Attaching to DOWNSTREAM:" << downstream;
   }
   if(init_request_body_buf() == -1) {
@@ -107,7 +107,7 @@ int SpdyDownstreamConnection::attach_downstream(Downstream *downstream)
 
 void SpdyDownstreamConnection::detach_downstream(Downstream *downstream)
 {
-  if(ENABLE_LOG) {
+  if(LOG_ENABLED(INFO)) {
     DCLOG(INFO, this) << "Detaching from DOWNSTREAM:" << downstream;
   }
   downstream->set_downstream_connection(0);
@@ -293,7 +293,7 @@ int SpdyDownstreamConnection::push_request_headers()
     nv[hdidx++] = via_value.c_str();
   }
   nv[hdidx++] = 0;
-  if(ENABLE_LOG) {
+  if(LOG_ENABLED(INFO)) {
     std::stringstream ss;
     for(size_t i = 0; nv[i]; i += 2) {
       ss << TTY_HTTP_HD << nv[i] << TTY_RST << ": " << nv[i+1] << "\n";
diff --git a/src/shrpx_spdy_session.cc b/src/shrpx_spdy_session.cc
index 3c78379..f177d86 100644
--- a/src/shrpx_spdy_session.cc
+++ b/src/shrpx_spdy_session.cc
@@ -65,7 +65,7 @@ SpdySession::~SpdySession()
 
 int SpdySession::disconnect()
 {
-  if(ENABLE_LOG) {
+  if(LOG_ENABLED(INFO)) {
     SSLOG(INFO, this) << "Disconnecting";
   }
   spdylay_session_del(session_);
@@ -217,7 +217,7 @@ void eventcb(bufferevent *bev, short events, void *ptr)
 {
   SpdySession *spdy = reinterpret_cast<SpdySession*>(ptr);
   if(events & BEV_EVENT_CONNECTED) {
-    if(ENABLE_LOG) {
+    if(LOG_ENABLED(INFO)) {
       SSLOG(INFO, spdy) << "Connection established";
     }
     spdy->connected();
@@ -231,12 +231,12 @@ void eventcb(bufferevent *bev, short events, void *ptr)
     setsockopt(fd, IPPROTO_TCP, TCP_NODELAY,
                reinterpret_cast<char *>(&val), sizeof(val));
   } else if(events & BEV_EVENT_EOF) {
-    if(ENABLE_LOG) {
+    if(LOG_ENABLED(INFO)) {
       SSLOG(INFO, spdy) << "EOF";
     }
     spdy->disconnect();
   } else if(events & (BEV_EVENT_ERROR | BEV_EVENT_TIMEOUT)) {
-    if(ENABLE_LOG) {
+    if(LOG_ENABLED(INFO)) {
       if(events & BEV_EVENT_ERROR) {
         SSLOG(INFO, spdy) << "Network error";
       } else {
@@ -257,7 +257,7 @@ int SpdySession::initiate_connection()
 {
   int rv;
   assert(state_ == DISCONNECTED);
-  if(ENABLE_LOG) {
+  if(LOG_ENABLED(INFO)) {
     SSLOG(INFO, this) << "Connecting to downstream server";
   }
 
@@ -461,7 +461,7 @@ void on_stream_close_callback
 {
   int rv;
   SpdySession *spdy = reinterpret_cast<SpdySession*>(user_data);
-  if(ENABLE_LOG) {
+  if(LOG_ENABLED(INFO)) {
     SSLOG(INFO, spdy) << "Stream stream_id=" << stream_id
                       << " is being closed";
   }
@@ -507,7 +507,7 @@ void on_ctrl_recv_callback
   Downstream *downstream;
   switch(type) {
   case SPDYLAY_SYN_STREAM:
-    if(ENABLE_LOG) {
+    if(LOG_ENABLED(INFO)) {
       SSLOG(INFO, spdy) << "Received upstream SYN_STREAM stream_id="
                         << frame->syn_stream.stream_id;
     }
@@ -594,7 +594,7 @@ void on_ctrl_recv_callback
       }
     }
 
-    if(ENABLE_LOG) {
+    if(LOG_ENABLED(INFO)) {
       std::stringstream ss;
       for(size_t i = 0; nv[i]; i += 2) {
         ss << TTY_HTTP_HD << nv[i] << TTY_RST << ": " << nv[i+1] << "\n";
@@ -645,7 +645,7 @@ void on_data_chunk_recv_callback(spdylay_session *session,
   if(spdy->get_flow_control()) {
     sd->dconn->inc_recv_window_size(len);
     if(sd->dconn->get_recv_window_size() > spdy->get_initial_window_size()) {
-      if(ENABLE_LOG) {
+      if(LOG_ENABLED(INFO)) {
         SSLOG(INFO, spdy) << "Flow control error: recv_window_size="
                           << sd->dconn->get_recv_window_size()
                           << ", initial_window_size="
@@ -740,7 +740,7 @@ void on_ctrl_recv_parse_error_callback(spdylay_session *session,
                                        void *user_data)
 {
   SpdySession *spdy = reinterpret_cast<SpdySession*>(user_data);
-  if(ENABLE_LOG) {
+  if(LOG_ENABLED(INFO)) {
     SSLOG(INFO, spdy) << "Failed to parse received control frame. type="
                       << type
                       << ", error_code=" << error_code << ":"
@@ -756,7 +756,7 @@ void on_unknown_ctrl_recv_callback(spdylay_session *session,
                                    void *user_data)
 {
   SpdySession *spdy = reinterpret_cast<SpdySession*>(user_data);
-  if(ENABLE_LOG) {
+  if(LOG_ENABLED(INFO)) {
     SSLOG(INFO, spdy) << "Received unknown control frame";
   }
 }
@@ -769,7 +769,7 @@ int SpdySession::on_connect()
   unsigned int next_proto_len;
   SSL_get0_next_proto_negotiated(ssl_, &next_proto, &next_proto_len);
 
-  if(ENABLE_LOG) {
+  if(LOG_ENABLED(INFO)) {
     std::string proto(next_proto, next_proto+next_proto_len);
     SSLOG(INFO, this) << "Negotiated next protocol: " << proto;
   }
@@ -851,7 +851,7 @@ int SpdySession::on_read()
   if(rv == 0) {
     if(spdylay_session_want_read(session_) == 0 &&
        spdylay_session_want_write(session_) == 0) {
-      if(ENABLE_LOG) {
+      if(LOG_ENABLED(INFO)) {
         SSLOG(INFO, this) << "No more read/write for this session";
       }
       rv = -1;
@@ -875,7 +875,7 @@ int SpdySession::send()
   if(rv == 0) {
     if(spdylay_session_want_read(session_) == 0 &&
        spdylay_session_want_write(session_) == 0) {
-      if(ENABLE_LOG) {
+      if(LOG_ENABLED(INFO)) {
         SSLOG(INFO, this) << "No more read/write for this session";
       }
       rv = -1;
diff --git a/src/shrpx_spdy_upstream.cc b/src/shrpx_spdy_upstream.cc
index 6be82f0..85608ef 100644
--- a/src/shrpx_spdy_upstream.cc
+++ b/src/shrpx_spdy_upstream.cc
@@ -95,7 +95,7 @@ void on_stream_close_callback
  void *user_data)
 {
   SpdyUpstream *upstream = reinterpret_cast<SpdyUpstream*>(user_data);
-  if(ENABLE_LOG) {
+  if(LOG_ENABLED(INFO)) {
     ULOG(INFO, upstream) << "Stream stream_id=" << stream_id
                          << " is being closed";
   }
@@ -143,7 +143,7 @@ void on_ctrl_recv_callback
   SpdyUpstream *upstream = reinterpret_cast<SpdyUpstream*>(user_data);
   switch(type) {
   case SPDYLAY_SYN_STREAM: {
-    if(ENABLE_LOG) {
+    if(LOG_ENABLED(INFO)) {
       ULOG(INFO, upstream) << "Received upstream SYN_STREAM stream_id="
                            << frame->syn_stream.stream_id;
     }
@@ -192,7 +192,7 @@ void on_ctrl_recv_callback
       downstream->add_request_header("X-Forwarded-Spdy", "true");
     }
 
-    if(ENABLE_LOG) {
+    if(LOG_ENABLED(INFO)) {
       std::stringstream ss;
       for(size_t i = 0; nv[i]; i += 2) {
         ss << TTY_HTTP_HD << nv[i] << TTY_RST << ": " << nv[i+1] << "\n";
@@ -245,7 +245,7 @@ void on_data_chunk_recv_callback(spdylay_session *session,
       downstream->inc_recv_window_size(len);
       if(downstream->get_recv_window_size() >
          upstream->get_initial_window_size()) {
-        if(ENABLE_LOG) {
+        if(LOG_ENABLED(INFO)) {
           ULOG(INFO, upstream) << "Flow control error: recv_window_size="
                                << downstream->get_recv_window_size()
                                << ", initial_window_size="
@@ -292,7 +292,7 @@ void on_ctrl_recv_parse_error_callback(spdylay_session *session,
                                        void *user_data)
 {
   SpdyUpstream *upstream = reinterpret_cast<SpdyUpstream*>(user_data);
-  if(ENABLE_LOG) {
+  if(LOG_ENABLED(INFO)) {
     ULOG(INFO, upstream) << "Failed to parse received control frame. type="
                          << type
                          << ", error_code=" << error_code << ":"
@@ -308,7 +308,7 @@ void on_unknown_ctrl_recv_callback(spdylay_session *session,
                                    void *user_data)
 {
   SpdyUpstream *upstream = reinterpret_cast<SpdyUpstream*>(user_data);
-  if(ENABLE_LOG) {
+  if(LOG_ENABLED(INFO)) {
     ULOG(INFO, upstream) << "Received unknown control frame.";
   }
 }
@@ -388,7 +388,7 @@ int SpdyUpstream::on_read()
   if(rv == 0) {
     if(spdylay_session_want_read(session_) == 0 &&
        spdylay_session_want_write(session_) == 0) {
-      if(ENABLE_LOG) {
+      if(LOG_ENABLED(INFO)) {
         ULOG(INFO, this) << "No more read/write for this SPDY session";
       }
       rv = -1;
@@ -413,7 +413,7 @@ int SpdyUpstream::send()
   if(rv == 0) {
     if(spdylay_session_want_read(session_) == 0 &&
        spdylay_session_want_write(session_) == 0) {
-      if(ENABLE_LOG) {
+      if(LOG_ENABLED(INFO)) {
         ULOG(INFO, this) << "No more read/write for this SPDY session";
       }
       rv = -1;
@@ -449,7 +449,7 @@ void spdy_downstream_readcb(bufferevent *bev, void *ptr)
   }
   int rv = downstream->on_read();
   if(rv != 0) {
-    if(ENABLE_LOG) {
+    if(LOG_ENABLED(INFO)) {
       DCLOG(INFO, dconn) << "HTTP parser failure";
     }
     if(downstream->get_response_state() == Downstream::HEADER_COMPLETE) {
@@ -502,7 +502,7 @@ void spdy_downstream_eventcb(bufferevent *bev, short events, void *ptr)
   SpdyUpstream *upstream;
   upstream = static_cast<SpdyUpstream*>(downstream->get_upstream());
   if(events & BEV_EVENT_CONNECTED) {
-    if(ENABLE_LOG) {
+    if(LOG_ENABLED(INFO)) {
       DCLOG(INFO, dconn) << "Connection established. stream_id="
                          << downstream->get_stream_id();
     }
@@ -511,7 +511,7 @@ void spdy_downstream_eventcb(bufferevent *bev, short events, void *ptr)
     setsockopt(fd, IPPROTO_TCP, TCP_NODELAY,
                reinterpret_cast<char *>(&val), sizeof(val));
   } else if(events & BEV_EVENT_EOF) {
-    if(ENABLE_LOG) {
+    if(LOG_ENABLED(INFO)) {
       DCLOG(INFO, dconn) << "EOF. stream_id=" << downstream->get_stream_id();
     }
     if(downstream->get_request_state() == Downstream::STREAM_CLOSED) {
@@ -528,7 +528,7 @@ void spdy_downstream_eventcb(bufferevent *bev, short events, void *ptr)
       // downstream wil be deleted in on_stream_close_callback.
       if(downstream->get_response_state() == Downstream::HEADER_COMPLETE) {
         // Server may indicate the end of the request by EOF
-        if(ENABLE_LOG) {
+        if(LOG_ENABLED(INFO)) {
           ULOG(INFO, upstream) << "Downstream body was ended by EOF";
         }
         downstream->set_response_state(Downstream::MSG_COMPLETE);
@@ -556,7 +556,7 @@ void spdy_downstream_eventcb(bufferevent *bev, short events, void *ptr)
       // At this point, downstream may be deleted.
     }
   } else if(events & (BEV_EVENT_ERROR | BEV_EVENT_TIMEOUT)) {
-    if(ENABLE_LOG) {
+    if(LOG_ENABLED(INFO)) {
       if(events & BEV_EVENT_ERROR) {
         DCLOG(INFO, dconn) << "Downstream network error: "
                            << evutil_socket_error_to_string
@@ -609,7 +609,7 @@ void spdy_downstream_eventcb(bufferevent *bev, short events, void *ptr)
 
 int SpdyUpstream::rst_stream(Downstream *downstream, int status_code)
 {
-  if(ENABLE_LOG) {
+  if(LOG_ENABLED(INFO)) {
     ULOG(INFO, this) << "RST_STREAM stream_id="
                      << downstream->get_stream_id();
   }
@@ -744,7 +744,7 @@ spdylay_session* SpdyUpstream::get_spdy_session()
 // spdylay_session_recv. These calls may delete downstream.
 int SpdyUpstream::on_downstream_header_complete(Downstream *downstream)
 {
-  if(ENABLE_LOG) {
+  if(LOG_ENABLED(INFO)) {
     DLOG(INFO, downstream) << "HTTP response header completed";
   }
   size_t nheader = downstream->get_response_headers().size();
@@ -781,7 +781,7 @@ int SpdyUpstream::on_downstream_header_complete(Downstream *downstream)
     nv[hdidx++] = via_value.c_str();
   }
   nv[hdidx++] = 0;
-  if(ENABLE_LOG) {
+  if(LOG_ENABLED(INFO)) {
     std::stringstream ss;
     for(size_t i = 0; nv[i]; i += 2) {
       ss << TTY_HTTP_HD << nv[i] << TTY_RST << ": " << nv[i+1] << "\n";
@@ -835,7 +835,7 @@ int SpdyUpstream::on_downstream_body(Downstream *downstream,
 // spdylay_session_recv. These calls may delete downstream.
 int SpdyUpstream::on_downstream_body_complete(Downstream *downstream)
 {
-  if(ENABLE_LOG) {
+  if(LOG_ENABLED(INFO)) {
     DLOG(INFO, downstream) << "HTTP response completed";
   }
   spdylay_session_resume_data(session_, downstream->get_stream_id());
diff --git a/src/shrpx_thread_event_receiver.cc b/src/shrpx_thread_event_receiver.cc
index 0603e03..3192f6e 100644
--- a/src/shrpx_thread_event_receiver.cc
+++ b/src/shrpx_thread_event_receiver.cc
@@ -47,7 +47,7 @@ void ThreadEventReceiver::on_read(bufferevent *bev)
   while(evbuffer_get_length(input) >= sizeof(WorkerEvent)) {
     WorkerEvent wev;
     evbuffer_remove(input, &wev, sizeof(WorkerEvent));
-    if(ENABLE_LOG) {
+    if(LOG_ENABLED(INFO)) {
       TLOG(INFO, this) << "WorkerEvent: client_fd=" << wev.client_fd
                        << ", addrlen=" << wev.client_addrlen;
     }
@@ -59,11 +59,11 @@ void ThreadEventReceiver::on_read(bufferevent *bev)
                                                 wev.client_addrlen);
     if(client_handler) {
       client_handler->set_spdy_session(spdy_);
-      if(ENABLE_LOG) {
+      if(LOG_ENABLED(INFO)) {
         TLOG(INFO, this) << "CLIENT_HANDLER:" << client_handler << " created";
       }
     } else {
-      if(ENABLE_LOG) {
+      if(LOG_ENABLED(INFO)) {
         TLOG(ERROR, this) << "ClientHandler creation failed";
       }
       close(wev.client_fd);