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As discussed on -current, remove the hardcoded default maxswzone.

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MFC after:	3 weeks
This commit is contained in:
Dag-Erling Smørgrav 2012-08-14 17:01:21 +00:00
parent 8684fef07d
commit e2082935f0
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=239255
3 changed files with 20 additions and 27 deletions
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8
sys/amd64/include/param.h
View File

@ -122,14 +122,6 @@
#endif
#define KSTACK_GUARD_PAGES 1 /* pages of kstack guard; 0 disables */
/*
* Ceiling on amount of swblock kva space, can be changed via
* the kern.maxswzone /boot/loader.conf variable.
*/
#ifndef VM_SWZONE_SIZE_MAX
#define VM_SWZONE_SIZE_MAX (32 * 1024 * 1024)
#endif
/*
* Mach derived conversion macros
*/

31
sys/boot/common/loader.8
View File

@ -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

8
sys/i386/include/param.h
View File

@ -122,14 +122,6 @@
#endif
#define KSTACK_GUARD_PAGES 1 /* pages of kstack guard; 0 disables */
/*
* Ceiling on amount of swblock kva space, can be changed via
* the kern.maxswzone /boot/loader.conf variable.
*/
#ifndef VM_SWZONE_SIZE_MAX
#define VM_SWZONE_SIZE_MAX (32 * 1024 * 1024)
#endif
/*
* Ceiling on size of buffer cache (really only effects write queueing,
* the VM page cache is not effected), can be changed via