Date: Fri, 20 Sep 2002 11:20:14 -0700 (PDT) From: Robert Watson <rwatson@FreeBSD.ORG> To: freebsd-bugs@FreeBSD.org Subject: Re: kern/42937: panic when ARP cache uses up all mbufs Message-ID: <200209201820.g8KIKEMn035687@freefall.freebsd.org>
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The following reply was made to PR kern/42937; it has been noted by GNATS. From: Robert Watson <rwatson@FreeBSD.ORG> To: "George V. Neville-Neil" <gnn@waits.engr.nominum.com> Cc: FreeBSD-gnats-submit@FreeBSD.ORG Subject: Re: kern/42937: panic when ARP cache uses up all mbufs Date: Fri, 20 Sep 2002 14:18:09 -0400 (EDT) A potential fix for this problem would be to place a bound on the number (total size?) of mbufs permitted to be allocated for holding onto packets pending an arp resolution. Since interfaces are potentially lossy anyway due to queuing issues, protocols should recover. Such a "solution" would be easy to implement in that it would be a constant (possibly scaled based on some or another configuration parameter) in addition to an outstanding count for the number of saved packets. If adding a packet to the saved packet set would exceed the limit, then don't. Another possibly strategy is to have two seperate timeouts: the current long timeout for an arp query to expire, but a second shorter timeout for dropping data that is waiting on the arp. I.e., if arp doesn't complete in thirty seconds, drop the packet that caused the arp, but allow the arp process to continue the full give minutes. Robert N M Watson FreeBSD Core Team, TrustedBSD Projects robert@fledge.watson.org Network Associates Laboratories To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-bugs" in the body of the message
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