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author | des <des@FreeBSD.org> | 2012-08-14 17:01:21 +0000 |
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committer | des <des@FreeBSD.org> | 2012-08-14 17:01:21 +0000 |
commit | 0c96728586b059b0713dcf45101abcfdb8d1310a (patch) | |
tree | 7d20beffd1daa12873a58736daa1ebbb0813f21a /sys/boot/common | |
parent | 8eab28ac2fb3af91a7a0b82f1470294637b9719f (diff) | |
download | FreeBSD-src-0c96728586b059b0713dcf45101abcfdb8d1310a.zip FreeBSD-src-0c96728586b059b0713dcf45101abcfdb8d1310a.tar.gz |
As discussed on -current, remove the hardcoded default maxswzone.
MFC after: 3 weeks
Diffstat (limited to 'sys/boot/common')
-rw-r--r-- | sys/boot/common/loader.8 | 31 |
1 files changed, 20 insertions, 11 deletions
diff --git a/sys/boot/common/loader.8 b/sys/boot/common/loader.8 index 36f260c..7386f72 100644 --- a/sys/boot/common/loader.8 +++ b/sys/boot/common/loader.8 @@ -613,17 +613,26 @@ Not all architectures use such buffers; see for details. .It Va kern.maxswzone Limits the amount of KVM to be used to hold swap -meta information, which directly governs the -maximum amount of swap the system can support. -This value is specified in bytes of KVA space -and defaults to 32MBytes on i386 and amd64. -Care should be taken -to not reduce this value such that the actual -amount of configured swap exceeds 1/2 the -kernel-supported swap. -The default of 32MB allows -the kernel to support a maximum of ~7GB of swap. -Only change +metadata, which directly governs the +maximum amount of swap the system can support, +at the rate of approximately 200 MB of swap space +per 1 MB of metadata. +This value is specified in bytes of KVA space. +If no value is provided, the system allocates +enough memory to handle an amount of swap +that corresponds to eight times the amount of +physical memory present in the system. +.Pp +Note that swap metadata can be fragmented, +which means that the system can run out of +space before it reaches the theoretical limit. +Therefore, care should be taken to not configure +more swap than approximately half of the +theoretical maximum. +.Pp +Running out of space for swap metadata can leave +the system in an unrecoverable state. +Therefore, you should only change this parameter if you need to greatly extend the KVM reservation for other resources such as the buffer cache or |