91 lines
3.4 KiB
C
91 lines
3.4 KiB
C
/* $NetBSD: uvm_pglist.h,v 1.11 2020/04/13 15:16:14 ad Exp $ */
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/*-
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* Copyright (c) 2000, 2001, 2008, 2019 The NetBSD Foundation, Inc.
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* All rights reserved.
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*
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* This code is derived from software contributed to The NetBSD Foundation
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* by Jason R. Thorpe, and by Andrew Doran.
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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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*
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* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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#ifndef _UVM_UVM_PGLIST_H_
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#define _UVM_UVM_PGLIST_H_
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#include <sys/param.h>
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/*
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* This defines the type of a page queue, e.g. active list, inactive
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* list, etc.
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*/
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struct vm_page;
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TAILQ_HEAD(pglist, vm_page);
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LIST_HEAD(pgflist, vm_page);
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/*
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* The global uvm.page_free list (uvm_page.c, uvm_pglist.c). Free pages are
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* stored according to freelist, bucket, and cache colour.
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*
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* pglist = &uvm.page_free[freelist].pgfl_buckets[bucket].pgb_color[color];
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*
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* Freelists provide a priority ordering of pages for allocation, based upon
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* how valuable they are for special uses (e.g. device driver DMA). MD
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* code decides the number and structure of these. They are always arranged
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* in descending order of allocation priority.
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*
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* Pages are then grouped in buckets according to some common factor, for
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* example L2/L3 cache locality. Each bucket has its own lock, and the
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* locks are shared among freelists for the same numbered buckets.
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*
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* Inside each bucket, pages are further distributed by cache color.
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*
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* We want these data structures to occupy as few cache lines as possible,
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* as they will be highly contended.
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*/
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struct pgflbucket {
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uintptr_t pgb_nfree; /* total # free pages, all colors */
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struct pgflist pgb_colors[1]; /* variable size array */
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};
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/*
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* 8 buckets should be enough to cover most all current x86 systems (2019),
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* given the way package/core/smt IDs are structured on x86. For systems
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* that report high package counts despite having a single physical CPU
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* package (e.g. Ampere eMAG) a little bit of sharing isn't going to hurt.
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*/
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#define PGFL_MAX_BUCKETS 8
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struct pgfreelist {
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struct pgflbucket *pgfl_buckets[PGFL_MAX_BUCKETS];
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};
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/*
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* Lock for each bucket.
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*/
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union uvm_freelist_lock {
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kmutex_t lock;
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uint8_t padding[COHERENCY_UNIT];
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};
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extern union uvm_freelist_lock uvm_freelist_locks[PGFL_MAX_BUCKETS];
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#endif /* _UVM_UVM_PGLIST_H_ */
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