This patch introduces per-cgroup tcp buffers limitation. This allows sysadmins to specify a maximum amount of kernel memory that tcp connections can use at any point in time. TCP is the main interest in this work, but extending it to other protocols would be easy. For this to work, I am hooking it into memcg, after the introdution of an extension for tracking and controlling objects in kernel memory. Since they are usually not found in page granularity, and are fundamentally different from userspace memory (not swappable, can't overcommit), they need their special place inside the Memory Controller. Right now, the kmem extension is quite basic, and just lays down the basic infrastucture for the ongoing work. Although it does not account kernel memory allocated - I preferred to keep this series simple and leave accounting to the slab allocations when they arrive. What it does is to piggyback in the memory control mechanism already present in /proc/sys/net/ipv4/tcp_mem. There is a soft limit, and a hard limit, that will suppress allocation when reached. For each cgroup, however, the file kmem.tcp_maxmem will be used to cap those values. The usage I have in mind here is containers. Each container will define its own values for soft and hard limits, but none of them will be possibly bigger than the value the box' sysadmin specified from the outside. To test for any performance impacts of this patch, I used netperf's TCP_RR benchmark on localhost, so we can have both recv and snd in action. Command line used was ./src/netperf -t TCP_RR -H localhost, and the results: Without the patch ================= Socket Size Request Resp. Elapsed Trans. Send Recv Size Size Time Rate bytes Bytes bytes bytes secs. per sec 16384 87380 1 1 10.00 26996.35 16384 87380 With the patch =============== Local /Remote Socket Size Request Resp. Elapsed Trans. Send Recv Size Size Time Rate bytes Bytes bytes bytes secs. per sec 16384 87380 1 1 10.00 27291.86 16384 87380 The difference is within a one-percent range. Nesting cgroups doesn't seem to be the dominating factor as well, with nestings up to 10 levels not showing a significant performance difference. Glauber Costa (7): Basic kernel memory functionality for the Memory Controller socket: initial cgroup code. foundations of per-cgroup memory pressure controlling. per-cgroup tcp buffers control per-netns ipv4 sysctl_tcp_mem tcp buffer limitation: per-cgroup limit Display current tcp memory allocation in kmem cgroup Documentation/cgroups/memory.txt | 31 +++- crypto/af_alg.c | 7 +- include/linux/memcontrol.h | 84 +++++++++ include/net/netns/ipv4.h | 1 + include/net/sock.h | 126 +++++++++++++- include/net/tcp.h | 14 +- include/net/udp.h | 3 +- include/trace/events/sock.h | 10 +- init/Kconfig | 11 ++ mm/memcontrol.c | 354 +++++++++++++++++++++++++++++++++++++- net/core/sock.c | 93 +++++++--- net/decnet/af_decnet.c | 21 ++- net/ipv4/proc.c | 7 +- net/ipv4/sysctl_net_ipv4.c | 71 +++++++- net/ipv4/tcp.c | 58 ++++--- net/ipv4/tcp_input.c | 12 +- net/ipv4/tcp_ipv4.c | 18 ++- net/ipv4/tcp_output.c | 2 +- net/ipv4/tcp_timer.c | 2 +- net/ipv4/udp.c | 20 ++- net/ipv6/tcp_ipv6.c | 16 +- net/ipv6/udp.c | 4 +- net/sctp/socket.c | 35 +++- 23 files changed, 876 insertions(+), 124 deletions(-) -- 1.7.6 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>