Denys Fedoryshchenko a écrit :

Here is output from dmesg with patch you supplied.

Kup /config # rtstat -i60 -c60
rt_cache|rt_cache|rt_cache|rt_cache|rt_cache|rt_cache|rt_cache|rt_cache|
rt_cache|rt_cache|rt_cache|rt_cache|rt_cache|rt_cache|rt_cache|rt_cache|
rt_cache|
 entries|  in_hit|in_slow_|in_slow_|in_no_ro|  in_brd|in_marti|in_marti| 
out_hit|out_slow|out_slow|gc_total|gc_ignor|gc_goal_|gc_dst_o|in_hlist|
out_hlis|
        |        |     tot|      mc|     ute|        |  an_dst|  
an_src|        |    _tot|     _mc|        |      ed|    miss| verflow| 
_search|t_search|
  103266|   69986|   11574|       0|      54|       0|       0|       0|    
1982|     634|       0|   10984|   10980|       0|       0|  191808|    5254|
  124787|   45125|    6019|       0|      28|       0|       0|       0|     
807|     230|       0|    6277|    6274|       0|       0|  128922|    2518|
  120270|   45588|    6288|       0|      30|       0|       0|       0|     
883|     214|       0|    6532|    6529|       0|       0|  125651|    2743|
  122253|   46522|    6582|       0|      27|       0|       0|       0|     
897|     213|       0|    6822|    6819|       0|       0|  124927|    2761|

[  102.534363] dst_total: 120397 delayed: 12 work_perf: 0 expires: 27999 
elapsed: 1 us
[  130.530240] dst_total: 124277 delayed: 12 work_perf: 0 expires: 32998 
elapsed: 2 us
[  163.523240] dst_total: 110006 delayed: 12 work_perf: 0 expires: 39000 
elapsed: 1 us
[  202.519402] dst_total: 130453 delayed: 12 work_perf: 0 expires: 45998 
elapsed: 1 us
[  248.511220] dst_total: 110637 delayed: 12 work_perf: 0 expires: 52600 
elapsed: 2 us
[  301.102445] dst_total: 129366 delayed: 12 work_perf: 0 expires: 60696 
elapsed: 6 us

After while

Kup /config # rtstat -i300 -c60
rt_cache|rt_cache|rt_cache|rt_cache|rt_cache|rt_cache|rt_cache|rt_cache|
rt_cache|rt_cache|rt_cache|rt_cache|rt_cache|rt_cache|rt_cache|rt_cache|
rt_cache|
 entries|  in_hit|in_slow_|in_slow_|in_no_ro|  in_brd|in_marti|in_marti| 
out_hit|out_slow|out_slow|gc_total|gc_ignor|gc_goal_|gc_dst_o|in_hlist|
out_hlis|
        |        |     tot|      mc|     ute|        |  an_dst|  
an_src|        |    _tot|     _mc|        |      ed|    miss| verflow| 
_search|t_search|
  129138|   64166|    9864|       0|      46|       0|       0|       0|    
1334|     358|       0|   10012|   10008|       0|       0|  173006|    3985|
  130125|   43971|   10829|       0|      70|       0|       0|       0|     
907|     195|       0|   11093|   11090|       0|       0|  100601|    2848|
  144857|   32041|   22233|       0|     234|       0|       0|       0|     
738|     261|       0|   22727|   22724|       2|       0|   42769|     811|

[  687.740779] dst_total: 129365 delayed: 12 work_perf: 0 expires: 104999 
elapsed: 1 us
[  792.736043] dst_total: 127247 delayed: 101589 work_perf: 0 expires: 600 
elapsed: 11274 us
[  793.347127] dst_total: 122440 delayed: 101589 work_perf: 0 expires: 1600 
elapsed: 11150 us
[  794.957419] dst_total: 123780 delayed: 101589 work_perf: 0 expires: 3100 
elapsed: 10896 us
[  798.068614] dst_total: 121992 delayed: 101589 work_perf: 0 expires: 5655 
elapsed: 11561 us
[  803.734450] dst_total: 120552 delayed: 101589 work_perf: 0 expires: 7988 
elapsed: 12254 us
[  811.733227] dst_total: 121105 delayed: 101589 work_perf: 0 expires: 10988 
elapsed: 12209 us
[  822.733196] dst_total: 120142 delayed: 101589 work_perf: 0 expires: 13987 
elapsed: 12039 us
[  836.730637] dst_total: 120823 delayed: 101589 work_perf: 0 expires: 17987 
elapsed: 12448 us
[  854.726913] dst_total: 127478 delayed: 101589 work_perf: 0 expires: 22988 
elapsed: 11435 us
[  877.724827] dst_total: 127497 delayed: 101589 work_perf: 0 expires: 27987 
elapsed: 12833 us
[  905.719818] dst_total: 126693 delayed: 101589 work_perf: 0 expires: 32987 
elapsed: 12068 us
[  938.714595] dst_total: 130740 delayed: 101589 work_perf: 0 expires: 38988 
elapsed: 11970 us
[  977.707568] dst_total: 135449 delayed: 101589 work_perf: 0 expires: 45989 
elapsed: 11747 us
[ 1023.701554] dst_total: 141181 delayed: 101589 work_perf: 0 expires: 52988 
elapsed: 12653 us
[ 1076.694012] dst_total: 147895 delayed: 101588 work_perf: 1 expires: 59987 
elapsed: 12217 us
[ 1136.684805] dst_total: 154798 delayed: 101588 work_perf: 0 expires: 67987 
elapsed: 12026 us
[ 1204.673424] dst_total: 163376 delayed: 101588 work_perf: 0 expires: 76988 
elapsed: 11151 us

and after 30 minutes more

Kup /config # rtstat -i300 -c60
rt_cache|rt_cache|rt_cache|rt_cache|rt_cache|rt_cache|rt_cache|rt_cache|
rt_cache|rt_cache|rt_cache|rt_cache|rt_cache|rt_cache|rt_cache|rt_cache|
rt_cache|
 entries|  in_hit|in_slow_|in_slow_|in_no_ro|  in_brd|in_marti|in_marti| 
out_hit|out_slow|out_slow|gc_total|gc_ignor|gc_goal_|gc_dst_o|in_hlist|
out_hlis|
        |        |     tot|      mc|     ute|        |  an_dst|  
an_src|        |    _tot|     _mc|        |      ed|    miss| verflow| 
_search|t_search|
  194841|  176962|   77964|       0|     684|       1|       0|       0|    
3939|    1143|       0|   79531|   79516|       7|       0|  401258|    9455|
  223224|   28262|   26499|       0|     236|       0|       0|       0|     
661|     216|       0|   26951|   26947|       3|       0|   93059|    1946|
  248425|   28257|   26784|       0|     226|       0|       0|       0|     
678|     202|       0|   27211|   27208|       3|       0|  115593|    2412|
  272823|   28943|   26728|       0|     246|       0|       0|       0|     
695|     200|       0|   27174|   27171|       3|       0|  135256|    2942|
  295087|   28835|   26701|       0|     252|       0|       0|       0|     
687|     194|       0|   27146|   27143|       3|       0|  154269|    3312|


[ 2043.547879] dst_total: 242922 delayed: 101588 work_perf: 0 expires: 119987 
elapsed: 12519 us
[ 2163.529997] dst_total: 252951 delayed: 101588 work_perf: 0 expires: 119987 
elapsed: 13930 us
[ 2283.512215] dst_total: 262678 delayed: 101588 work_perf: 0 expires: 119986 
elapsed: 14330 us
[ 2403.508447] dst_total: 271930 delayed: 101588 work_perf: 0 expires: 119972 
elapsed: 15230 us
[ 2523.476844] dst_total: 288046 delayed: 101588 work_perf: 0 expires: 119985 
elapsed: 15018 us
[ 2643.456996] dst_total: 296475 delayed: 101588 work_perf: 0 expires: 119987 
elapsed: 13654 us
[ 2763.438267] dst_total: 305033 delayed: 101588 work_perf: 0 expires: 119987 
elapsed: 13137 us

  

Very interesting... you can see 101588 dst are *delayed* in dst_garbage, 
but apparently never freed.

Something is wrong, but the count seems stable. Must be some kind of 
event, admin driven or something...
might be the "ip route flush cache" that is schedlued around 600 seconds 
of machine alive, then secret_interval seconds later...

Typically, when a "ip route flush cache" is done (manually or triggered 
by secret_interval timer), refcounted>0 entries are put into dst_garbage.

Then when some trafic occurs on the flows involved, IP stack should 
decrement refcount so that next dst_garbage round can free the deleted 
entries. Normal TCP connections are doing this correctly. On your 
machine, nothing.

Possibly idle tcp sessions ?

Maybe some netfilter problem ?

Please tell us more about your machine ;)