1 /*- 2 * Copyright (c) 2009-2010 Fabio Checconi 3 * Copyright (c) 2009-2010 Luigi Rizzo, Universita` di Pisa 4 * All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND 16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE 19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25 * SUCH DAMAGE. 26 */ 27 28 #ifndef _G_SCHED_H_ 29 #define _G_SCHED_H_ 30 31 /* 32 * $Id$ 33 * $FreeBSD$ 34 * 35 * Header for the geom_sched class (userland library and kernel part). 36 * See g_sched.c for documentation. 37 * The userland code only needs the three G_SCHED_* values below. 38 */ 39 40 #define G_SCHED_CLASS_NAME "SCHED" 41 #define G_SCHED_VERSION 0 42 #define G_SCHED_SUFFIX ".sched." 43 44 #ifdef _KERNEL 45 #define G_SCHED_DEBUG(lvl, ...) do { \ 46 if (me.gs_debug >= (lvl)) { \ 47 printf("GEOM_SCHED"); \ 48 if (me.gs_debug > 0) \ 49 printf("[%u]", lvl); \ 50 printf(": "); \ 51 printf(__VA_ARGS__); \ 52 printf("\n"); \ 53 } \ 54 } while (0) 55 56 #define G_SCHED_LOGREQ(bp, ...) do { \ 57 if (me.gs_debug >= 2) { \ 58 printf("GEOM_SCHED[2]: "); \ 59 printf(__VA_ARGS__); \ 60 printf(" "); \ 61 g_print_bio(bp); \ 62 printf("\n"); \ 63 } \ 64 } while (0) 65 66 LIST_HEAD(g_hash, g_sched_class); 67 68 /* 69 * Descriptor of a scheduler. 70 * In addition to the obvious fields, sc_flushing and sc_pending 71 * support dynamic switching of scheduling algorithm. 72 * Normally, sc_flushing is 0, and requests that are scheduled are 73 * also added to the sc_pending queue, and removed when we receive 74 * the 'done' event. 75 * 76 * When we are transparently inserted on an existing provider, 77 * sc_proxying is set. The detach procedure is slightly different. 78 * 79 * When switching schedulers, sc_flushing is set so requests bypass us, 80 * and at the same time we update the pointer in the pending bios 81 * to ignore us when they return up. 82 * XXX it would be more efficient to implement sc_pending with 83 * a generation number: the softc generation is increased when 84 * we change scheduling algorithm, we store the current generation 85 * number in the pending bios, and when they come back we ignore 86 * the done() call if the generation number do not match. 87 */ 88 struct g_sched_softc { 89 /* 90 * Generic fields used by any scheduling algorithm: 91 * a mutex, the class descriptor, flags, list of pending 92 * requests (used when flushing the module) and support 93 * for hash tables where we store per-flow queues. 94 */ 95 struct mtx sc_mtx; 96 struct g_gsched *sc_gsched; /* Scheduler descriptor. */ 97 int sc_pending; /* Pending requests. */ 98 int sc_flags; /* Various flags. */ 99 100 /* 101 * Hash tables to store per-flow queues are generally useful 102 * so we handle them in the common code. 103 * sc_hash and sc_mask are parameters of the hash table, 104 * the last two fields are used to periodically remove 105 * expired items from the hash table. 106 */ 107 struct g_hash *sc_hash; 108 u_long sc_mask; 109 int sc_flush_ticks; /* Next tick for a flush. */ 110 int sc_flush_bucket; /* Next bucket to flush. */ 111 112 /* 113 * Pointer to the algorithm's private data, which is the value 114 * returned by sc_gsched->gs_init() . A NULL here means failure. 115 * XXX intptr_t might be more appropriate. 116 */ 117 void *sc_data; 118 }; 119 120 #define G_SCHED_PROXYING 1 121 #define G_SCHED_FLUSHING 2 122 123 /* 124 * Temporary- our own version of the disksort, because the 125 * version in 7.x and 8.x before march 2009 is buggy. 126 */ 127 void gs_bioq_init(struct bio_queue_head *); 128 void gs_bioq_remove(struct bio_queue_head *, struct bio *); 129 void gs_bioq_flush(struct bio_queue_head *, struct devstat *, int); 130 void gs_bioq_insert_head(struct bio_queue_head *, struct bio *); 131 void gs_bioq_insert_tail(struct bio_queue_head *, struct bio *); 132 struct bio *gs_bioq_first(struct bio_queue_head *); 133 struct bio *gs_bioq_takefirst(struct bio_queue_head *); 134 void gs_bioq_disksort(struct bio_queue_head *, struct bio *); 135 136 #endif /* _KERNEL */ 137 138 #endif /* _G_SCHED_H_ */ 139