2446e4f02c
This allocator uses a binary buddy system with a twist. First and foremost, this allocator is required to support the implementation of superpages. As a side effect, it enables a more robust implementation of contigmalloc(9). Moreover, this reimplementation of contigmalloc(9) eliminates the acquisition of Giant by contigmalloc(..., M_NOWAIT, ...). The twist is that this allocator tries to reduce the number of TLB misses incurred by accesses through a direct map to small, UMA-managed objects and page table pages. Roughly speaking, the physical pages that are allocated for such purposes are clustered together in the physical address space. The performance benefits vary. In the most extreme case, a uniprocessor kernel running on an Opteron, I measured an 18% reduction in system time during a buildworld. This allocator does not implement page coloring. The reason is that superpages have much the same effect. The contiguous physical memory allocation necessary for a superpage is inherently colored. Finally, the one caveat is that this allocator does not effectively support prezeroed pages. I hope this is temporary. On i386, this is a slight pessimization. However, on amd64, the beneficial effects of the direct-map optimization outweigh the ill effects. I speculate that this is true in general of machines with a direct map. Approved by: re
146 lines
4.3 KiB
C
146 lines
4.3 KiB
C
/*-
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* Copyright (C) 1995, 1996 Wolfgang Solfrank.
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* Copyright (C) 1995, 1996 TooLs GmbH.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by TooLs GmbH.
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* 4. The name of TooLs GmbH may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
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* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
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* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
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* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* $NetBSD: vmparam.h,v 1.11 2000/02/11 19:25:16 thorpej Exp $
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* $FreeBSD$
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*/
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#ifndef _MACHINE_VMPARAM_H_
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#define _MACHINE_VMPARAM_H_
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#define USRSTACK VM_MAXUSER_ADDRESS
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#ifndef MAXTSIZ
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#define MAXTSIZ (16*1024*1024) /* max text size */
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#endif
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#ifndef DFLDSIZ
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#define DFLDSIZ (32*1024*1024) /* default data size */
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#endif
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#ifndef MAXDSIZ
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#define MAXDSIZ (512*1024*1024) /* max data size */
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#endif
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#ifndef DFLSSIZ
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#define DFLSSIZ (1*1024*1024) /* default stack size */
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#endif
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#ifndef MAXSSIZ
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#define MAXSSIZ (32*1024*1024) /* max stack size */
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#endif
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/*
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* Size of shared memory map
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*/
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#ifndef SHMMAXPGS
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#define SHMMAXPGS 1024
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#endif
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/*
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* The time for a process to be blocked before being very swappable.
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* This is a number of seconds which the system takes as being a non-trivial
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* amount of real time. You probably shouldn't change this;
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* it is used in subtle ways (fractions and multiples of it are, that is, like
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* half of a ``long time'', almost a long time, etc.)
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* It is related to human patience and other factors which don't really
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* change over time.
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*/
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#define MAXSLP 20
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/*
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* Use the direct-mapped BAT registers for UMA small allocs. This
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* takes pressure off the small amount of available KVA.
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*/
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#define UMA_MD_SMALL_ALLOC
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/*
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* Would like to have MAX addresses = 0, but this doesn't (currently) work
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*/
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#define VM_MIN_ADDRESS ((vm_offset_t)0)
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#define VM_MAXUSER_ADDRESS ((vm_offset_t)0x7ffff000)
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#define VM_MAX_ADDRESS VM_MAXUSER_ADDRESS
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#define VM_MIN_KERNEL_ADDRESS ((vm_offset_t)(KERNEL_SR << ADDR_SR_SHFT))
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#define VM_MAX_KERNEL_ADDRESS (VM_MIN_KERNEL_ADDRESS + 2*SEGMENT_LENGTH - 1)
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#define KERNBASE 0x100000 /* start of kernel virtual */
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/* XXX max. amount of KVM to be used by buffers. */
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#ifndef VM_MAX_KERNEL_BUF
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#define VM_MAX_KERNEL_BUF (SEGMENT_LENGTH * 7 / 10)
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#endif
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struct pmap_physseg {
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struct pv_entry *pvent;
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char *attrs;
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};
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#define VM_PHYSSEG_MAX 16 /* 1? */
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/*
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* The physical address space is densely populated.
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*/
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#define VM_PHYSSEG_DENSE
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/*
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* Create two free page pools: VM_FREEPOOL_DEFAULT is the default pool
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* from which physical pages are allocated and VM_FREEPOOL_DIRECT is
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* the pool from which physical pages for small UMA objects are
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* allocated.
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*/
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#define VM_NFREEPOOL 2
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#define VM_FREEPOOL_DEFAULT 0
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#define VM_FREEPOOL_DIRECT 1
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/*
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* Create one free page list.
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*/
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#define VM_NFREELIST 1
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#define VM_FREELIST_DEFAULT 0
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/*
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* The largest allocation size is 4MB.
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*/
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#define VM_NFREEORDER 11
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#ifndef VM_INITIAL_PAGEIN
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#define VM_INITIAL_PAGEIN 16
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#endif
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#ifndef SGROWSIZ
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#define SGROWSIZ (128UL*1024) /* amount to grow stack */
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#endif
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#ifndef VM_KMEM_SIZE
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#define VM_KMEM_SIZE (12 * 1024 * 1024)
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#endif
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#endif /* _MACHINE_VMPARAM_H_ */
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