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Allow maxusers to scale on machines with large address space.

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Some hooks are added to clamp down maxusers and nmbclusters for
small address space systems.

VM_MAX_AUTOTUNE_MAXUSERS - the max maxusers that will be autotuned based on
physical memory.
VM_MAX_AUTOTUNE_NMBCLUSTERS - max nmbclusters based on physical memory.

These are set to the old values on i386 to preserve the clamping that was
being done to all arches.

Another macro VM_AUTOTUNE_NMBCLUSTERS is provided to allow an override
for the calculation on a MD basis.  Currently no arch defines this.

Reviewed by: peter
MFC after: 2 weeks
This commit is contained in:
Alfred Perlstein 2012-11-10 02:08:40 +00:00
parent a9b09a3f3c
commit 79f62ed690
3 changed files with 30 additions and 12 deletions
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9
sys/i386/include/vmparam.h
View File

@ -202,4 +202,13 @@
#define ZERO_REGION_SIZE (64 * 1024) /* 64KB */
#ifndef VM_MAX_AUTOTUNE_MAXUSERS
#define VM_MAX_AUTOTUNE_MAXUSERS 384
#endif
#ifndef VM_MAX_AUTOTUNE_NMBCLUSTERS
/* old maxusers max value. */
#define VM_MAX_AUTOTUNE_NMBCLUSTERS (1024 + VM_MAX_AUTOTUNE_MAXUSERS * 64)
#endif
#endif /* _MACHINE_VMPARAM_H_ */

11
sys/kern/kern_mbuf.c
View File

@ -113,8 +113,17 @@ tunable_mbinit(void *dummy)
/* This has to be done before VM init. */
TUNABLE_INT_FETCH("kern.ipc.nmbclusters", &nmbclusters);
if (nmbclusters == 0)
if (nmbclusters == 0) {
#ifdef VM_AUTOTUNE_NMBCLUSTERS
nmbclusters = VM_AUTOTUNE_NMBCLUSTERS;
#else
nmbclusters = 1024 + maxusers * 64;
#endif
#ifdef VM_MAX_AUTOTUNE_NMBCLUSTERS
if (nmbclusters > VM_MAX_AUTOTUNE_NMBCLUSTERS)
nmbclusters = VM_MAX_AUTOTUNE_NMBCLUSTERS;
#endif
}
TUNABLE_INT_FETCH("kern.ipc.nmbjumbop", &nmbjumbop);
if (nmbjumbop == 0)

22
sys/kern/subr_param.c
View File

@ -278,17 +278,17 @@ init_param2(long physpages)
maxusers = physpages / (2 * 1024 * 1024 / PAGE_SIZE);
if (maxusers < 32)
maxusers = 32;
/*
* Clips maxusers to 384 on machines with <= 4GB RAM or 32bit.
* Scales it down 6x for large memory machines.
*/
if (maxusers > 384) {
if (sizeof(void *) <= 4)
maxusers = 384;
else
maxusers = 384 + ((maxusers - 384) / 6);
}
}
#ifdef VM_MAX_AUTOTUNE_MAXUSERS
if (maxusers > VM_MAX_AUTOTUNE_MAXUSERS)
maxusers = VM_MAX_AUTOTUNE_MAXUSERS;
#endif
/*
* Scales down the function in which maxusers grows once
* we hit 384.
*/
if (maxusers > 384)
maxusers = 384 + ((maxusers - 384) / 8);
}
/*
* The following can be overridden after boot via sysctl. Note: