Date: Fri, 1 Feb 2002 21:15:11 -0600 From: "Mike Meyer" <mwm-dated-1013051711.4d56c3@mired.org> To: Mathieu Arnold <ma@absolight.fr> Cc: questions@freebsd.org Subject: Re: the LINT file Message-ID: <15451.22975.341409.741888@guru.mired.org> In-Reply-To: <4125715@toto.iv>
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Mathieu Arnold <ma@absolight.fr> types: > Mathieu Arnold wrote: > > I'm actually upgrading one of my test box from 4_4 to 4_5, and I > > stumbled on this : > > > > # Tune the kernel malloc area parameters. VM_KMEM_SIZE represents the > > # minimum, in bytes, and is typically (12*1024*1024) (12MB). > > # VM_KMEM_SIZE_MAX represents the maximum, typically 200 megabytes. > > # VM_KMEM_SIZE_SCALE can be set to adjust the auto-tuning factor, which > > # typically defaults to 4 (kernel malloc area size is physical memory > > # divided by the scale factor). > > # > > options VM_KMEM_SIZE="(10*1024*1024)" > > options VM_KMEM_SIZE_MAX="(100*1024*1024)" > > options VM_KMEM_SIZE_SCALE="4" > > > > the comment says that VM_KMEM_SIZE is set to 12MB but it's set to 10, > > and that _MAX is set to 200 but it's set to 100... > > I heard once that if the comment and the code differed, they were both > > wrong :) Note that, for each variable, the comment says that it is "typically" set to those values. LINT isn't your typical kernel config. > > so, what should be the default values ? Check GENERIC, that's the kernel that's installed on FreeBSD by default. > # Tune the buffer cache maximum KVA reservation, in bytes. The maximum > is > # usually capped at 200 MB, effecting machines with > 1GB of ram. Note > # that the buffer cache only really governs write buffering and disk > block > # translations. The VM page cache is our primary disk cache and is not > # effected by the size of the buffer cache. > # > options VM_BCACHE_SIZE_MAX="(100*1024*1024)" > > it says 200M in the comment, but 100 in the code It also says "usually" in the comment. > # Tune the swap zone KVA reservation, in bytes. The default is > typically > # 70 MB, giving the system the ability to manage a maximum of 28GB worth > # of swapped out data. > # > options VM_SWZONE_SIZE_MAX="(50*1024*1024)" > > 70 -> 50... And again, it says "typically". You apparently didn't read the first part of LINT: # LINT -- config file for checking all the sources, tries to pull in # as much of the source tree as it can. I.e. - it's a file for checking the sources. Changing parameters from their default values is part of that checking. A little further down, you find: # NB: You probably don't want to try running a kernel built from this # file. Instead, you should start from GENERIC, and add options from # this file as required. Start with GENERIC. Read LINT to find more options, or to find out more about the options in GENERIC. <mike -- Mike Meyer <mwm@mired.org> http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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