Date: Thu, 5 Dec 2002 14:43:07 +0000 (GMT) From: Jan Grant <Jan.Grant@bristol.ac.uk> To: Varshavchick Alexander <alex@metrocom.ru> Cc: Terry Lambert <tlambert2@mindspring.com>, freebsd-questions <freebsd-questions@FreeBSD.ORG>, freebsd-hackers <freebsd-hackers@FreeBSD.ORG> Subject: Re: maxusers and random system freezes Message-ID: <Pine.GSO.4.44.0212051439440.12073-100000@mail.ilrt.bris.ac.uk> In-Reply-To: <Pine.GSO.4.33.0212051552400.7912-100000@apache.metrocom.ru>
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On Thu, 5 Dec 2002, Varshavchick Alexander wrote: > On Thu, 5 Dec 2002, Terry Lambert wrote: > > > IMO, KVA need to be more than half of physical memory. But I tend > > to use a lot of mbufs and mbuf clusters in products I work on lately > > (mostly networking stuff). If you don't tune kernel memory usage up, > > then you may be able to get away with 2G. > > A question arises. The value 256 (1G KVA space) acts as a default for any > system installation, not depending of real phisical memory size. So for > any server with RAM less than 2G (which is a majority I presume) the KVA > space occupies more than half of physical memory. It can even be more than > TOTAL phisical memory for servers with RAM less than 1G. Isn't it bad for > a system? It seems that it is not. Then why cannot the KVA space always be > made as some big value? If it is important for servers with large RAM, why > it is not or a smaller servers? > > Can anybody besides Terry which seems to be unavailable now help? It controls the split between virtual address space, not allocation of physical memory. If KVA is turned up to 3GB (say) then userland virtual address space for all processes is limited to 1GB (each). For Terry's stuff (networking, mostly, and probably mostly in the kernel anyway) this is beneficial. For (to pick an example at random) anyone running java* or other large userland processes, having only 1GB of elbow-space (physical or virtual) is often not sufficient. jan * "You've plenty of resources" and "an infinite number of threads are bound to make fair progress" seem to be a summation of "the java way" :-) -- jan grant, ILRT, University of Bristol. http://www.ilrt.bris.ac.uk/ Tel +44(0)117 9287088 Fax +44 (0)117 9287112 http://ioctl.org/jan/ Work #90: As many pseudo-intellectual sycophants as necessary to make one inarticulate scotsman think he's a genius in command of The Profound. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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