Date: Fri, 6 Sep 2002 15:47:49 +0300 From: Giorgos Keramidas <keramida@ceid.upatras.gr> To: Wahyu Hidayat <wahyuhid@yahoo.com> Cc: freebsd-questions@FreeBSD.org Subject: Re: running out of mbuf Message-ID: <20020906124749.GD2168@hades.hell.gr> In-Reply-To: <20020906022036.90263.qmail@web40013.mail.yahoo.com> References: <20020905184835.P1069@seven.alameda.net> <20020906022036.90263.qmail@web40013.mail.yahoo.com>
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[-- Removed freebsd-stable from the Cc: header. ------] [-- Please do not cross post to more than one list. --] On 2002-09-05 19:20 +0000, Wahyu Hidayat wrote: > Thanks for all your immediate reply. > > Sure I have raised NMBCLUSTERS (in my netstat shows to > 20480). > > What is the explanation for my previous post about max > mbufs has not reached, but it already shows about mbuf > allocation failed ? What if I increase nmbclusters but > this problems still occurs ? Mbufs are internal kernel structures used for buffering network data. When an mbuf needs to hold a lot of data, an `mbuf cluster' is attached to it as extra space. You have a lot of free mbufs to use, but your clusters are running out. This way when someone requests that an mbuf is allocated to hold a large amount of data the allocation that has two stages (first allocate an mbuf, then a cluster to attach to it) fails during the second stage--the mbuf cluster allocation. Looking at the netstat -m output you have posted: > 22070/22544/81920 mbufs in use (current/peak/max): > 20490 mbufs allocated to data > 1580 mbufs allocated to packet headers > 20462/20480/20480 mbuf clusters in use (current/peak/max) > 46596 Kbytes allocated to network (7% of mb_map in use) > 87932 requests for memory denied > 274 requests for memory delayed > 0 calls to protocol drain routines you can easily see that the peak use of mbuf clusters is 100%. When all of your mbuf clusters have been used, an allocation that will request more clusters will fail. This is what happens, when you are getting those messages. - Giorgos To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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