Re: Memory leak in ip_dst_cache
flat view
From: Kumar S <hidden>
Date: 2011-09-09 20:54:52
Hi Eric, I did not flush those routes explicitly. They are flushed out automatically by calling "rt_run_flush". It inturn calls rt_free(), but __cache_free() never gets called after that. Basically, I have 512 MBytes of memory on board. I want to restrict the cache to around 64k, with max_size. But if I do that due to this leak, TCP/IP communication stops working when it reaches 64k. Thanks psk ----- Original Message ----- From: Eric Dumazet <redacted> To: Kumar S <redacted> Cc: Sent: Friday, September 9, 2011 12:33 PM Subject: Re: Memory leak in ip_dst_cache Le vendredi 09 septembre 2011 à 11:39 -0700, Kumar S a écrit :
Hi Eric, Thanks for the response. Here is the output of the commands you mentioned.
Hmm, you should have included netdev in this message.
After injecting around11k routes: -sh-2.05b# -sh-2.05b# ip route ls cache | wc 23256 162772 1166903 -sh-2.05b# After route flush out: -sh-2.05b# -sh-2.05b# ip route ls cache | wc 14 88 710 -sh-2.05b# -sh-2.05b# -sh-2.05b# -sh-2.05b# cat /proc/slabinfo | grep ip_dst ip_dst_cache 11673 11685 256 15 1 : tunables 120 60 0 : slabdata 779 779 0
Thats OK : Each tcp session has a pointer to a dst. When you "ip route flush cache", busy dst are all invalidated. "ip route ls cache" doesnt output invalidated dsts. As soon as tcp session will try to send a packet, it will notice the dst is obsolete and 'free' it.
-sh-2.05b# -sh-2.05b# grep . /proc/sys/net/ipv4/route/* /proc/sys/net/ipv4/route/error_burst:1250 /proc/sys/net/ipv4/route/error_cost:250 grep: /proc/sys/net/ipv4/route/flush: Permission denied /proc/sys/net/ipv4/route/gc_elasticity:8 /proc/sys/net/ipv4/route/gc_interval:60 /proc/sys/net/ipv4/route/gc_min_interval:0 /proc/sys/net/ipv4/route/gc_min_interval_ms:500 /proc/sys/net/ipv4/route/gc_thresh:16384 /proc/sys/net/ipv4/route/gc_timeout:300 /proc/sys/net/ipv4/route/max_delay:10 /proc/sys/net/ipv4/route/max_size:2097152 /proc/sys/net/ipv4/route/min_adv_mss:256 /proc/sys/net/ipv4/route/min_delay:2 /proc/sys/net/ipv4/route/min_pmtu:552 /proc/sys/net/ipv4/route/mtu_expires:600 /proc/sys/net/ipv4/route/redirect_load:5 /proc/sys/net/ipv4/route/redirect_number:9 /proc/sys/net/ipv4/route/redirect_silence:5120 /proc/sys/net/ipv4/route/secret_interval:600 -sh-2.05b# rtstat -c10 -i1 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| 11675| 27700| 101014| 0| 0| 130| 0| 0| 36284| 23436| 0| 0| 0| 0| 0| 9658| 23140| 11675| 6| 18| 0| 0| 0| 0| 0| 2| 0| 0| 0| 0| 0| 0| 0| 0| 11675| 2| 10| 0| 0| 0| 0| 0| 2| 0| 0| 0| 0| 0| 0| 0| 0| 11675| 8| 18| 0| 0| 0| 0| 0| 2| 0| 0| 0| 0| 0| 0| 0| 0| 11675| 6| 18| 0| 0| 0| 0| 0| 2| 0| 0| 0| 0| 0| 0| 0| 0| 11675| 4| 16| 0| 0| 0| 0| 0| 4| 0| 0| 0| 0| 0| 0| 0| 0| 11675| 8| 12| 0| 0| 0| 0| 0| 2| 0| 0| 0| 0| 0| 0| 0| 0| 11675| 6| 10| 0| 0| 0| 0| 0| 2| 0| 0| 0| 0| 0| 0| 0| 0| 11675| 2| 14| 0| 0| 0| 0| 0| 2| 0| 0| 0| 0| 0| 0| 0| 0| 11675| 8| 12| 0| 0| 0| 0| 0| 2| 0| 0| 0| 0| 0| 0| 0| 0| -sh-2.05b#
Thats pretty low ip route usage, you dont need to tweak your tunables. Thanks