139 lines
4.8 KiB
C
139 lines
4.8 KiB
C
/*-
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* Copyright (c) 2009-2010 Fabio Checconi
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* Copyright (c) 2009-2010 Luigi Rizzo, Universita` di Pisa
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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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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#ifndef _G_SCHED_H_
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#define _G_SCHED_H_
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/*
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* $Id$
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* $FreeBSD$
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*
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* Header for the geom_sched class (userland library and kernel part).
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* See g_sched.c for documentation.
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* The userland code only needs the three G_SCHED_* values below.
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*/
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#define G_SCHED_CLASS_NAME "SCHED"
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#define G_SCHED_VERSION 0
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#define G_SCHED_SUFFIX ".sched."
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#ifdef _KERNEL
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#define G_SCHED_DEBUG(lvl, ...) do { \
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if (me.gs_debug >= (lvl)) { \
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printf("GEOM_SCHED"); \
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if (me.gs_debug > 0) \
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printf("[%u]", lvl); \
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printf(": "); \
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printf(__VA_ARGS__); \
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printf("\n"); \
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} \
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} while (0)
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#define G_SCHED_LOGREQ(bp, ...) do { \
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if (me.gs_debug >= 2) { \
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printf("GEOM_SCHED[2]: "); \
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printf(__VA_ARGS__); \
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printf(" "); \
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g_print_bio(bp); \
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printf("\n"); \
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} \
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} while (0)
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LIST_HEAD(g_hash, g_sched_class);
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/*
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* Descriptor of a scheduler.
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* In addition to the obvious fields, sc_flushing and sc_pending
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* support dynamic switching of scheduling algorithm.
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* Normally, sc_flushing is 0, and requests that are scheduled are
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* also added to the sc_pending queue, and removed when we receive
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* the 'done' event.
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*
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* When we are transparently inserted on an existing provider,
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* sc_proxying is set. The detach procedure is slightly different.
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*
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* When switching schedulers, sc_flushing is set so requests bypass us,
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* and at the same time we update the pointer in the pending bios
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* to ignore us when they return up.
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* XXX it would be more efficient to implement sc_pending with
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* a generation number: the softc generation is increased when
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* we change scheduling algorithm, we store the current generation
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* number in the pending bios, and when they come back we ignore
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* the done() call if the generation number do not match.
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*/
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struct g_sched_softc {
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/*
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* Generic fields used by any scheduling algorithm:
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* a mutex, the class descriptor, flags, list of pending
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* requests (used when flushing the module) and support
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* for hash tables where we store per-flow queues.
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*/
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struct mtx sc_mtx;
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struct g_gsched *sc_gsched; /* Scheduler descriptor. */
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int sc_pending; /* Pending requests. */
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int sc_flags; /* Various flags. */
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/*
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* Hash tables to store per-flow queues are generally useful
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* so we handle them in the common code.
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* sc_hash and sc_mask are parameters of the hash table,
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* the last two fields are used to periodically remove
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* expired items from the hash table.
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*/
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struct g_hash *sc_hash;
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u_long sc_mask;
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int sc_flush_ticks; /* Next tick for a flush. */
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int sc_flush_bucket; /* Next bucket to flush. */
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/*
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* Pointer to the algorithm's private data, which is the value
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* returned by sc_gsched->gs_init() . A NULL here means failure.
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* XXX intptr_t might be more appropriate.
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*/
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void *sc_data;
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};
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#define G_SCHED_PROXYING 1
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#define G_SCHED_FLUSHING 2
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/*
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* Temporary- our own version of the disksort, because the
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* version in 7.x and 8.x before march 2009 is buggy.
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*/
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void gs_bioq_init(struct bio_queue_head *);
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void gs_bioq_remove(struct bio_queue_head *, struct bio *);
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void gs_bioq_flush(struct bio_queue_head *, struct devstat *, int);
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void gs_bioq_insert_head(struct bio_queue_head *, struct bio *);
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void gs_bioq_insert_tail(struct bio_queue_head *, struct bio *);
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struct bio *gs_bioq_first(struct bio_queue_head *);
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struct bio *gs_bioq_takefirst(struct bio_queue_head *);
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void gs_bioq_disksort(struct bio_queue_head *, struct bio *);
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#endif /* _KERNEL */
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#endif /* _G_SCHED_H_ */
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