1 /* $NetBSD: uvm_pglist.h,v 1.11 2020/04/13 15:16:14 ad Exp $ */ 2 3 /*- 4 * Copyright (c) 2000, 2001, 2008, 2019 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Jason R. Thorpe, and by Andrew Doran. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 #ifndef _UVM_UVM_PGLIST_H_ 33 #define _UVM_UVM_PGLIST_H_ 34 35 #include <sys/param.h> 36 37 /* 38 * This defines the type of a page queue, e.g. active list, inactive 39 * list, etc. 40 */ 41 struct vm_page; 42 TAILQ_HEAD(pglist, vm_page); 43 LIST_HEAD(pgflist, vm_page); 44 45 /* 46 * The global uvm.page_free list (uvm_page.c, uvm_pglist.c). Free pages are 47 * stored according to freelist, bucket, and cache colour. 48 * 49 * pglist = &uvm.page_free[freelist].pgfl_buckets[bucket].pgb_color[color]; 50 * 51 * Freelists provide a priority ordering of pages for allocation, based upon 52 * how valuable they are for special uses (e.g. device driver DMA). MD 53 * code decides the number and structure of these. They are always arranged 54 * in descending order of allocation priority. 55 * 56 * Pages are then grouped in buckets according to some common factor, for 57 * example L2/L3 cache locality. Each bucket has its own lock, and the 58 * locks are shared among freelists for the same numbered buckets. 59 * 60 * Inside each bucket, pages are further distributed by cache color. 61 * 62 * We want these data structures to occupy as few cache lines as possible, 63 * as they will be highly contended. 64 */ 65 struct pgflbucket { 66 uintptr_t pgb_nfree; /* total # free pages, all colors */ 67 struct pgflist pgb_colors[1]; /* variable size array */ 68 }; 69 70 /* 71 * 8 buckets should be enough to cover most all current x86 systems (2019), 72 * given the way package/core/smt IDs are structured on x86. For systems 73 * that report high package counts despite having a single physical CPU 74 * package (e.g. Ampere eMAG) a little bit of sharing isn't going to hurt. 75 */ 76 #define PGFL_MAX_BUCKETS 8 77 struct pgfreelist { 78 struct pgflbucket *pgfl_buckets[PGFL_MAX_BUCKETS]; 79 }; 80 81 /* 82 * Lock for each bucket. 83 */ 84 union uvm_freelist_lock { 85 kmutex_t lock; 86 uint8_t padding[COHERENCY_UNIT]; 87 }; 88 extern union uvm_freelist_lock uvm_freelist_locks[PGFL_MAX_BUCKETS]; 89 90 #endif /* _UVM_UVM_PGLIST_H_ */ 91