Date: Thu, 19 Jun 2003 01:49:47 -0700 From: David Schultz <das@freebsd.org> To: Peter Losher <Peter_Losher@isc.org> Cc: current@freebsd.org Subject: Re: Problems tuning kmem_map on 5.1-REL box. Message-ID: <20030619084947.GA80465@HAL9000.homeunix.com> In-Reply-To: <20030619070830.U26075@farside.isc.org> References: <20030617080628.H1802@farside.isc.org> <20030618083401.GA74409@HAL9000.homeunix.com> <20030619070830.U26075@farside.isc.org>
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On Thu, Jun 19, 2003, Peter Losher wrote: > On Wed, 18 Jun 2003, David Schultz wrote: > > > To allow the kmem_map to exceed 200 MB, you'll also need to tweak > > VM_KMEM_SIZE_MAX to (for example) '(1024 * 1024 * 1024)'. BTW, > > the formula, which I stole from vmparam.h, is: > > > > min(max(VM_KMEM_SIZE, Physical memory/VM_KMEM_SIZE_SCALE), VM_KMEM_SIZE_MAX) > > Looks like I may have found some kind of error, adding this to my kernel > config: > > # KVM > options VM_KMEM_SIZE_SCALE="4" > options VM_KMEM_SIZE_MAX="(1024 * 1024 * 1024)" > > (1024MB of KVM, 4096MB/4, 1024MB MAX KVM size) > > Cause the following warning and compile bomb: > > % config KVM_FIX > WARNING: unknown option `*' removed from ../compile/KVM_FIX/opt_vm.h This looks like a limitation of config(8). > Changing the options to: > > # KVM > options VM_KMEM_SIZE_SCALE="4" > options VM_KMEM_SIZE_MAX="(1024*1024*1024)" > > Configs and compiles cleanly, but panics when rebooting with the new > kernel: > > kmem_suballoc: bad status return of 3. > panic: kmem_suballoc That means there wasn't a large enough contiguous region for the kmem_map. I guess I forgot to tell you that you also need to adjust KVA_PAGES upwards so that the kernel has enough virtual address space to fit the map. The following should do: options KVA_PAGES=512
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