Re: Increasing MAXPHYS

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From: Matthew Dillon
Date: Saturday, March 20, 2010 - 11:22 am

:Pardon my ignorance, but wouldn't so much KVM make small embedded
:devices like Soekris boards with 128 MB of physical RAM totally unusable
:then? On my net4801, running RELENG_8:
:
:vm.kmem_size: 40878080
:
:hw.physmem: 125272064
:hw.usermen: 84840448
:hw.realmem: 134217728

    KVM != physical memory.  On i386 by default the kernel has 1G of KVM
    and userland has 3G.  While the partition can be moved to increase
    available KVM on i386 (e.g. 2G/2G), it isn't recommended.

    So the KVM reserved for various things does not generally impact
    physical memory use.

    The number of swap buffers (nswbuf) is scaled to 1/4 nbufs with a
    maximum of 256.  Systems with small amounts of memory should not be
    impacted.

    The issue w/ regards to KVM problems on i386 is mostly restricted to
    systems with 2G+ of ram where the kernel's various internal parameters
    are scaled to their maximum values or limits.  On systems with less ram
    the kernel's internal parameters are usually scaled down sufficiently
    that there is very little chance of the kernel running out of KVM.

						-Matt

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Messages in current thread:
Increasing MAXPHYS, Alexander Motin, (Sat Mar 20, 8:20 am)
Re: Increasing MAXPHYS, Matthew Dillon, (Sat Mar 20, 10:53 am)
Re: Increasing MAXPHYS, C. P. Ghost, (Sat Mar 20, 11:13 am)
Re: Increasing MAXPHYS, Scott Long, (Sat Mar 20, 11:17 am)
Re: Increasing MAXPHYS, Matthew Dillon, (Sat Mar 20, 11:22 am)
Re: Increasing MAXPHYS, Alexander Motin, (Sat Mar 20, 12:26 pm)
Re: Increasing MAXPHYS, Alan Cox, (Sat Mar 20, 12:38 pm)
Re: Increasing MAXPHYS, Julian Elischer, (Sat Mar 20, 1:41 pm)
Re: Increasing MAXPHYS, Julian Elischer, (Sat Mar 20, 2:30 pm)
Re: Increasing MAXPHYS, Alexander Motin, (Sun Mar 21, 7:04 am)
Re: Increasing MAXPHYS, Julian Elischer, (Sun Mar 21, 8:46 am)
Re: Increasing MAXPHYS, Ulrich =?utf-8?B?U3D ..., (Sun Mar 21, 9:30 am)
Re: Increasing MAXPHYS, Scott Long, (Sun Mar 21, 9:32 am)
Re: Increasing MAXPHYS, Scott Long, (Sun Mar 21, 9:39 am)
Re: Increasing MAXPHYS, Ulrich =?utf-8?B?U3D ..., (Sun Mar 21, 9:53 am)
Re: Increasing MAXPHYS, Alexander Motin, (Sun Mar 21, 10:03 am)
Re: Increasing MAXPHYS, Scott Long, (Sun Mar 21, 10:10 am)
Re: Increasing MAXPHYS, jhell, (Sun Mar 21, 5:54 pm)
Re: Increasing MAXPHYS, jhell, (Sun Mar 21, 7:00 pm)
Re: Increasing MAXPHYS, Alexander Motin, (Sun Mar 21, 10:53 pm)
Re: Increasing MAXPHYS, Gary Jennejohn, (Mon Mar 22, 4:40 am)
Re: Increasing MAXPHYS, John Baldwin, (Mon Mar 22, 5:39 am)
Re: Increasing MAXPHYS, Alexander Leidinger, (Mon Mar 22, 5:49 am)
Re: Increasing MAXPHYS, jhell, (Mon Mar 22, 8:11 am)
Re: Increasing MAXPHYS, Alexander Sack, (Mon Mar 22, 8:52 am)
Re: Increasing MAXPHYS, Scott Long, (Mon Mar 22, 9:27 am)