I have a need for multiple local nodes in LVS. I started from the patch from 2005: http://archive.linuxvirtualserver.org/html/lvs-users/2005-06/msg00113.html I found three problems with it: 1. packet checksums were not calculated correctly 2. having stats enabled would deadlock the kernel in the stats update function (ip_vs_in_stats/ip_vs_out_stats) 3. the kernel would deadlock in the packet recieve function (ip_vs_in) For #1, I believe this was because the existing code assumes the TCP/UDP checksums are correct (which is not true for locally generated packets with hardware checksum). I just used the same code that the tcp and udp functions use. For #2 and #3, the problem was that the majority of the code runs as a bottom handler. Locally generated packets are run as a normal kernel context. If a network interrupt happens while the kernel is holding a IPVS lock for sending a local packet, it can schedule the bottom handler. The bottom handler can then try to acquire the same lock, and this is a deadlock. To prevent this from happening, I've disabled bottom handlers (local_bh_disable) in the local packet output function I created (ip_vs_out_nobh). I've tested this and it works on a RH5/CentOS5 2.6.18.92.1.17.el5 kernel: http://dan.drown.org/software/ipvs-2.6.18-92.1.17.el5-multiple-local-nodes.patch I've ported it to a stock 2.6.27.7 kernel, but I haven't had time to test it out yet: http://dan.drown.org/software/ipvs-2.6.27.7-multiple-local-nodes.patch I welcome any comments or criticism on the code. -- To unsubscribe from this list: send the line "unsubscribe lvs-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
