disable SWIFT on private trackers, because they are typically ratio-based sites where you *want* to upload as much as possible to deadbeats

libtransmission/internal.h

@@ -43,6 +43,8 @@ typedef enum { TR_NET_OK, TR_NET_ERROR, TR_NET_WAIT } tr_tristate_t;
 #define FALSE 0
 #endif
 
+int tr_torrentIsPrivate( const tr_torrent * );
+
 void tr_torrentRecheckCompleteness( tr_torrent * );
 
 int tr_trackerInfoInit( struct tr_tracker_info  * info,

libtransmission/peer-msgs.c

@@ -1442,12 +1442,23 @@ sendKeepalive( tr_peermsgs * msgs )
 ***
 **/
 
+static int
+isSwiftEnabled( const tr_peermsgs * msgs )
+{
+    /* rationale: SWIFT is good for getting rid of deadbeats, but most
+     * private trackers have ratios where you _want_ to feed deadbeats
+     * as much as possible.  So we disable SWIFT on private torrents */
+    return SWIFT_ENABLED
+        && !tr_torrentIsSeed( msgs->torrent )
+        && !tr_torrentIsPrivate( msgs->torrent );
+}
+
 static size_t
 getUploadMax( const tr_peermsgs * msgs )
 {
     static const size_t maxval = ~0;
     const tr_torrent * tor = msgs->torrent;
-    const int useSwift = SWIFT_ENABLED && !tr_torrentIsSeed( msgs->torrent );
+    const int useSwift = isSwiftEnabled( msgs );
     const size_t swiftLeft = msgs->info->credit;
     size_t speedLeft;
     size_t bufLeft;

libtransmission/torrent.c

@@ -641,10 +641,19 @@ tr_torrentChangeMyPort( tr_torrent * tor )
         tr_trackerChangeMyPort( tor->tracker );
 }
 
+int
+tr_torrentIsPrivate( const tr_torrent * tor )
+{
+    return tor
+        && tor->info.isPrivate;
+}
+
 int
 tr_torrentIsPexEnabled( const tr_torrent * tor )
 {
-    return !tor->info.isPrivate && !tor->pexDisabled;
+    return tor
+        && !tr_torrentIsPrivate( tor )
+        && !tor->pexDisabled;
 }
 
 void