Date: Fri, 17 Sep 2010 07:36:32 +0000 (UTC) From: Andriy Gapon <avg@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r212784 - head/sys/amd64/include Message-ID: <201009170736.o8H7aWno022260@svn.freebsd.org>
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Author: avg Date: Fri Sep 17 07:36:32 2010 New Revision: 212784 URL: http://svn.freebsd.org/changeset/base/212784 Log: amd64: reduce VM_KMEM_SIZE_SCALE to 1 allowing kernel to use more memory KVA space is abundant on amd64, so there is no reason to limit kernel map size to a fraction of available physical memory. In fact, it could be larger than physical memory. This should help with memory auto-tuning for ZFS and shouldn't affect other workloads. This should reduce number of circumstances for "kmem_map too small" panics, but probably won't eliminate them entirely due to potential kmem fragmentation. In fact, you might want/need to limit maximum ARC size after this commit if you need to resrve more memory for applications. This change was discussed on arch@ and nobody said "don't do it". MFC after: 6 weeks Modified: head/sys/amd64/include/vmparam.h Modified: head/sys/amd64/include/vmparam.h ============================================================================== --- head/sys/amd64/include/vmparam.h Fri Sep 17 07:34:50 2010 (r212783) +++ head/sys/amd64/include/vmparam.h Fri Sep 17 07:36:32 2010 (r212784) @@ -205,7 +205,7 @@ * is the total KVA space allocated for kmem_map. */ #ifndef VM_KMEM_SIZE_SCALE -#define VM_KMEM_SIZE_SCALE (3) +#define VM_KMEM_SIZE_SCALE (1) #endif /*
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