freebsd-nq/sys/geom/sched/g_sched.h
Conrad Meyer ac03832ef3 GEOM: Reduce unnecessary log interleaving with sbufs
Similar to what was done for device_printfs in r347229.

Convert g_print_bio() to a thin shim around g_format_bio(), which acts on an
sbuf; documented in g_bio.9.

Reviewed by:	markj
Discussed with:	rlibby
Sponsored by:	Dell EMC Isilon
Differential Revision:	https://reviews.freebsd.org/D21165
2019-08-07 19:28:35 +00:00

112 lines
4.0 KiB
C

/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 2009-2010 Fabio Checconi
* Copyright (c) 2009-2010 Luigi Rizzo, Universita` di Pisa
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#ifndef _G_SCHED_H_
#define _G_SCHED_H_
/*
* $Id$
* $FreeBSD$
*
* Header for the geom_sched class (userland library and kernel part).
* See g_sched.c for documentation.
* The userland code only needs the three G_SCHED_* values below.
*/
#define G_SCHED_CLASS_NAME "SCHED"
#define G_SCHED_VERSION 0
#define G_SCHED_SUFFIX ".sched."
#ifdef _KERNEL
#define G_SCHED_DEBUG(lvl, ...) \
_GEOM_DEBUG("GEOM_SCHED", me.gs_debug, (lvl), NULL, __VA_ARGS__)
#define G_SCHED_LOGREQ(bp, ...) \
_GEOM_DEBUG("GEOM_SCHED", me.gs_debug, 2, (bp), __VA_ARGS__)
LIST_HEAD(g_hash, g_sched_class);
/*
* Descriptor of a scheduler.
* In addition to the obvious fields, sc_flushing and sc_pending
* support dynamic switching of scheduling algorithm.
* Normally, sc_flushing is 0, and requests that are scheduled are
* also added to the sc_pending queue, and removed when we receive
* the 'done' event.
*
* When we are transparently inserted on an existing provider,
* sc_proxying is set. The detach procedure is slightly different.
*
* When switching schedulers, sc_flushing is set so requests bypass us,
* and at the same time we update the pointer in the pending bios
* to ignore us when they return up.
* XXX it would be more efficient to implement sc_pending with
* a generation number: the softc generation is increased when
* we change scheduling algorithm, we store the current generation
* number in the pending bios, and when they come back we ignore
* the done() call if the generation number do not match.
*/
struct g_sched_softc {
/*
* Generic fields used by any scheduling algorithm:
* a mutex, the class descriptor, flags, list of pending
* requests (used when flushing the module) and support
* for hash tables where we store per-flow queues.
*/
struct mtx sc_mtx;
struct g_gsched *sc_gsched; /* Scheduler descriptor. */
int sc_pending; /* Pending requests. */
int sc_flags; /* Various flags. */
/*
* Hash tables to store per-flow queues are generally useful
* so we handle them in the common code.
* sc_hash and sc_mask are parameters of the hash table,
* the last two fields are used to periodically remove
* expired items from the hash table.
*/
struct g_hash *sc_hash;
u_long sc_mask;
int sc_flush_ticks; /* Next tick for a flush. */
int sc_flush_bucket; /* Next bucket to flush. */
/*
* Pointer to the algorithm's private data, which is the value
* returned by sc_gsched->gs_init() . A NULL here means failure.
* XXX intptr_t might be more appropriate.
*/
void *sc_data;
};
#define G_SCHED_PROXYING 1
#define G_SCHED_FLUSHING 2
#endif /* _KERNEL */
#endif /* _G_SCHED_H_ */