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author | dillon <dillon@FreeBSD.org> | 2001-08-20 00:41:12 +0000 |
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committer | dillon <dillon@FreeBSD.org> | 2001-08-20 00:41:12 +0000 |
commit | 05c33a209bd0403f851f4ffd54fe4d16a1a663ef (patch) | |
tree | 4f3fc469468f6ff18e20f33a23a0fca03e1113be /sys/boot/common | |
parent | 277945b1a7db16235f31ed390e6a74045bd62b5f (diff) | |
download | FreeBSD-src-05c33a209bd0403f851f4ffd54fe4d16a1a663ef.zip FreeBSD-src-05c33a209bd0403f851f4ffd54fe4d16a1a663ef.tar.gz |
Limit the amount of KVM reserved for the buffer cache and for swap-meta
information. The default limits only effect machines with > 1GB of ram
and can be overriden with two new kernel conf variables VM_SWZONE_SIZE_MAX
and VM_BCACHE_SIZE_MAX, or with loader variables kern.maxswzone and
kern.maxbcache. This has the effect of leaving more KVM available for
sizing NMBCLUSTERS and 'maxusers' and should avoid tripups where a sysad
adds memory to a machine and then sees the kernel panic on boot due to
running out of KVM.
Also change the default swap-meta auto-sizing calculation to allocate half
of what it was previously allocating. The prior defaults were way too high.
Note that we cannot afford to run out of swap-meta structures so we still
stay somewhat conservative here.
Diffstat (limited to 'sys/boot/common')
-rw-r--r-- | sys/boot/common/loader.8 | 27 |
1 files changed, 27 insertions, 0 deletions
diff --git a/sys/boot/common/loader.8 b/sys/boot/common/loader.8 index 730f925..2ee850b 100644 --- a/sys/boot/common/loader.8 +++ b/sys/boot/common/loader.8 @@ -409,6 +409,33 @@ This overrides completely the value determined when the kernel was compiled. Modifies .Va VM_KMEM_SIZE . +.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 around 70MBytes. 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 70MB allows +the kernel to support a maximum of (approximately) +14GB of configured swap. Only mess around with +this parameter if you need to greatly extend the +KVM reservation for other resources such as the +buffer cache or NMBCLUSTERS. Modifies +.Va VM_SWZONE_SIZE_MAX +.It Va kern.maxbcache +Limits the amount of KVM reserved for use by the +buffer cache, specified in bytes. The default +maximum is 200MB. This parameter is used to +prevent the buffer cache from eating to much +KVM in large-memory machine configurations. +Only mess around with this parameter if you need to +greatly extend the KVM reservation for other resources +such as the swap zone or NMBCLUSTERS. Note that +the NBUF parameter will override this limit. +Modifies +.Va VM_BCACHE_SIZE_MAX .It Va machdep.pccard.pcic_irq Overrides the IRQ normally assigned to a PCCARD controller. Typically the first available interrupt will be allocated, |