mars/kernel/mars_bio.h

/*
 * MARS Long Distance Replication Software
 *
 * This file is part of MARS project: http://schoebel.github.io/mars/
 *
 * Copyright (C) 2010-2014 Thomas Schoebel-Theuer
 * Copyright (C) 2011-2014 1&1 Internet AG
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#ifndef MARS_BIO_H
#define MARS_BIO_H

#define BIO_RESPONSE_THREADS 4

#define BIO_SUBMIT_MAX_LATENCY    250 // 250 us
#define BIO_IO_R_MAX_LATENCY    40000 //  40 ms
#define BIO_IO_W_MAX_LATENCY   100000 // 100 ms

#ifdef CONFIG_MARS_DEBUG
#define MARS_BIO_DEBUG
extern struct mars_limiter bio_throttle_read;
extern struct mars_limiter bio_throttle_write;
#endif

extern int bio_nr_requests;
extern struct threshold bio_submit_threshold;
extern struct threshold bio_io_threshold[2];

#include <linux/blkdev.h>

struct bio_mref_aspect {
	GENERIC_ASPECT(mref);
	struct list_head io_head;
	struct bio *bio;
	struct bio_output *output;
	unsigned long long start_stamp;
	int status_code;
	int alloc_len;
	bool do_dealloc;
};

struct bio_response {
	struct list_head completed_list;
	wait_queue_head_t response_event;
	brick_thread_t *response_thread;
	struct bio_brick *brick;
};

struct bio_brick {
	MARS_BRICK(bio);
	// tunables
	int ra_pages;
	int bg_threshold;
	int bg_maxfly;
	bool do_sync;
	bool do_unplug;
	// readonly
	loff_t total_size;
	atomic_t fly_count[MARS_PRIO_NR];
	atomic_t queue_count[MARS_PRIO_NR];
	atomic_t completed_count;
	int error;
#ifdef MARS_BIO_DEBUG
	atomic_t total_completed_count[MARS_PRIO_NR];
#endif
	// private
	spinlock_t lock;
	struct list_head queue_list[MARS_PRIO_NR];
	struct list_head submitted_list[2];
	wait_queue_head_t submit_event;
	struct mapfree_info *mf;
	struct block_device *bdev;
	brick_thread_t *submit_thread;
	struct bio_response rsp[BIO_RESPONSE_THREADS];
	unsigned int rsp_nr;
	int bvec_max;
	bool submitted;
};

struct bio_input {
	MARS_INPUT(bio);
};

struct bio_output {
	MARS_OUTPUT(bio);
};

MARS_TYPES(bio);

#endif