1/*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright (c) 2009-2010 Fabio Checconi 5 * Copyright (c) 2009-2010 Luigi Rizzo, Universita` di Pisa 6 * All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 */ 29 30#ifndef _G_SCHED_H_ 31#define _G_SCHED_H_ 32 33/* 34 * $Id$ 35 * $FreeBSD$ 36 * 37 * Header for the geom_sched class (userland library and kernel part). 38 * See g_sched.c for documentation. 39 * The userland code only needs the three G_SCHED_* values below. 40 */ 41 42#define G_SCHED_CLASS_NAME "SCHED" 43#define G_SCHED_VERSION 0 44#define G_SCHED_SUFFIX ".sched." 45 46#ifdef _KERNEL 47#define G_SCHED_DEBUG(lvl, ...) do { \ 48 if (me.gs_debug >= (lvl)) { \ 49 printf("GEOM_SCHED"); \ 50 if (me.gs_debug > 0) \ 51 printf("[%u]", lvl); \ 52 printf(": "); \ 53 printf(__VA_ARGS__); \ 54 printf("\n"); \ 55 } \ 56} while (0) 57 58#define G_SCHED_LOGREQ(bp, ...) do { \ 59 if (me.gs_debug >= 2) { \ 60 printf("GEOM_SCHED[2]: "); \ 61 printf(__VA_ARGS__); \ 62 printf(" "); \ 63 g_print_bio(bp); \ 64 printf("\n"); \ 65 } \ 66} while (0) 67 68LIST_HEAD(g_hash, g_sched_class); 69 70/* 71 * Descriptor of a scheduler. 72 * In addition to the obvious fields, sc_flushing and sc_pending 73 * support dynamic switching of scheduling algorithm. 74 * Normally, sc_flushing is 0, and requests that are scheduled are 75 * also added to the sc_pending queue, and removed when we receive 76 * the 'done' event. 77 * 78 * When we are transparently inserted on an existing provider, 79 * sc_proxying is set. The detach procedure is slightly different. 80 * 81 * When switching schedulers, sc_flushing is set so requests bypass us, 82 * and at the same time we update the pointer in the pending bios 83 * to ignore us when they return up. 84 * XXX it would be more efficient to implement sc_pending with 85 * a generation number: the softc generation is increased when 86 * we change scheduling algorithm, we store the current generation 87 * number in the pending bios, and when they come back we ignore 88 * the done() call if the generation number do not match. 89 */ 90struct g_sched_softc { 91 /* 92 * Generic fields used by any scheduling algorithm: 93 * a mutex, the class descriptor, flags, list of pending 94 * requests (used when flushing the module) and support 95 * for hash tables where we store per-flow queues. 96 */ 97 struct mtx sc_mtx; 98 struct g_gsched *sc_gsched; /* Scheduler descriptor. */ 99 int sc_pending; /* Pending requests. */ 100 int sc_flags; /* Various flags. */ 101 102 /* 103 * Hash tables to store per-flow queues are generally useful 104 * so we handle them in the common code. 105 * sc_hash and sc_mask are parameters of the hash table, 106 * the last two fields are used to periodically remove 107 * expired items from the hash table. 108 */ 109 struct g_hash *sc_hash; 110 u_long sc_mask; 111 int sc_flush_ticks; /* Next tick for a flush. */ 112 int sc_flush_bucket; /* Next bucket to flush. */ 113 114 /* 115 * Pointer to the algorithm's private data, which is the value 116 * returned by sc_gsched->gs_init() . A NULL here means failure. 117 * XXX intptr_t might be more appropriate. 118 */ 119 void *sc_data; 120}; 121 122#define G_SCHED_PROXYING 1 123#define G_SCHED_FLUSHING 2 124 125#endif /* _KERNEL */ 126 127#endif /* _G_SCHED_H_ */ 128