Date: Mon, 21 Apr 2008 17:16:28 +0900 From: gnn@freebsd.org To: gnn@freebsd.org Cc: Robert Watson <rwatson@freebsd.org>, net@freebsd.org Subject: Re: zonelimit issues... Message-ID: <m2mynn4o83.wl%gnn@neville-neil.com> In-Reply-To: <m2od834pmv.wl%gnn@neville-neil.com> References: <m2hcdztsx2.wl%gnn@neville-neil.com> <20080420102827.U67663@fledge.watson.org> <m2od834pmv.wl%gnn@neville-neil.com>
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At Mon, 21 Apr 2008 16:46:00 +0900, gnn@freebsd.org wrote: > > At Sun, 20 Apr 2008 10:32:25 +0100 (BST), > rwatson wrote: > > > > > > On Fri, 18 Apr 2008, gnn@freebsd.org wrote: > > > > > I am wondering why this patch was never committed? > > > > > > http://people.freebsd.org/~delphij/misc/patch-zonelimit-workaround > > > > > > It does seem to address an issue I'm seeing where processes get into the > > > zonelimit state through the use of mbufs (a high speed UDP packet receiver) > > > but even after network pressure is reduced/removed the process never gets > > > out of that state again. Applying the patch fixed the issue, but I'd like > > > to have some discussion as to the general merits of the approach. > > > > > > Unfortunately the test that currently causes this is tied very tightly to > > > code at work that I can't share, but I will hopefully be improving mctest to > > > try to exhibit this behavior. > > > > When you take all load off the system, do mbufs and clusters get properly > > freed back to UMA (as visible in netstat -m)? If not, continuing to bump up > > against the zonelimit would suggest an mbuf/cluster leak, in which case we > > need to track that bug. > > > > This is unclear as the process that creates the issue opens 50 UDP > multicast sockets with very large socket buffers. I am investigating > this aspect some more. > OK, yes, the clusters etc. go back to normal when the incoming pressure is released. I do not believe we have a cluster/mbuf leak. Best, George
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