rate limit outstanding-disk performance warnings. don't throttle reading form peers because of disk congestion if the peer isn't downloading payload. Don't time out peers that are not waiting on the network

include/libtorrent/aux_/session_impl.hpp

@@ -730,6 +730,8 @@ namespace libtorrent
 
 			ptime m_last_tick;
 			ptime m_last_second_tick;
+			// used to limit how often disk warnings are generated
+			ptime m_last_disk_performance_warning;
 
 			// the last time we went through the peers
 			// to decide which ones to choke/unchoke

src/peer_connection.cpp

@@ -2402,8 +2402,10 @@ namespace libtorrent
 
 		if (t->filesystem().queued_bytes() >= m_ses.settings().max_queued_disk_bytes
 			&& m_ses.settings().max_queued_disk_bytes
-			&& t->alerts().should_post<performance_alert>())
+			&& t->alerts().should_post<performance_alert>()
+			&& (now - m_ses.m_last_disk_performance_warning) > seconds(10))
 		{
+			m_ses.m_last_disk_performance_warning = now;
 			t->alerts().post_alert(performance_alert(t->get_handle()
 				, performance_alert::outstanding_disk_buffer_limit_reached));
 		}
@@ -3857,11 +3859,12 @@ namespace libtorrent
 		// time, it is considered to have timed out
 		time_duration d;
 		d = now - m_last_receive;
+
 		// if we can't read, it means we're blocked on the rate-limiter
 		// or the disk, not the peer itself. In this case, don't blame
 		// the peer and disconnect it
-		bool may_timeout = can_read()
-;
+		bool may_timeout = (m_channel_state[download_channel] == peer_info::bw_network);
+
 		if (may_timeout && d > seconds(m_timeout) && !m_connecting)
 		{
 #if defined TORRENT_VERBOSE_LOGGING || defined TORRENT_ERROR_LOGGING
@@ -4995,7 +4998,10 @@ namespace libtorrent
 
 		bool disk = m_ses.settings().max_queued_disk_bytes == 0
 			|| !t || t->get_storage() == 0
-			|| t->filesystem().queued_bytes() < m_ses.settings().max_queued_disk_bytes;
+			|| t->filesystem().queued_bytes() < m_ses.settings().max_queued_disk_bytes
+			// don't block this peer because of disk saturation
+			// if we're not downloading any pieces from it
+			|| m_outstanding_bytes == 0;
 
 		if (!disk)
 		{

src/session_impl.cpp

@@ -499,6 +499,7 @@ namespace aux {
 		, m_created(time_now_hires())
 		, m_last_tick(m_created)
 		, m_last_second_tick(m_created - milliseconds(900))
+		, m_last_disk_performance_warning(min_time())
 		, m_last_choke(m_created)
 		, m_next_rss_update(min_time())
 #ifndef TORRENT_DISABLE_DHT