[linux-2.6-block.git] / fs / fscache / main.c

/* General filesystem local caching manager
 *
 * Copyright (C) 2004-2007 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 *
 * 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.
 */

#define FSCACHE_DEBUG_LEVEL CACHE
#include <linux/module.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/completion.h>
#include <linux/slab.h>
#include <linux/seq_file.h>
#define CREATE_TRACE_POINTS
#include "internal.h"

MODULE_DESCRIPTION("FS Cache Manager");
MODULE_AUTHOR("Red Hat, Inc.");
MODULE_LICENSE("GPL");

unsigned fscache_defer_lookup = 1;
module_param_named(defer_lookup, fscache_defer_lookup, uint,
		   S_IWUSR | S_IRUGO);
MODULE_PARM_DESC(fscache_defer_lookup,
		 "Defer cookie lookup to background thread");

unsigned fscache_defer_create = 1;
module_param_named(defer_create, fscache_defer_create, uint,
		   S_IWUSR | S_IRUGO);
MODULE_PARM_DESC(fscache_defer_create,
		 "Defer cookie creation to background thread");

unsigned fscache_debug;
module_param_named(debug, fscache_debug, uint,
		   S_IWUSR | S_IRUGO);
MODULE_PARM_DESC(fscache_debug,
		 "FS-Cache debugging mask");

struct kobject *fscache_root;
struct workqueue_struct *fscache_object_wq;
struct workqueue_struct *fscache_op_wq;

DEFINE_PER_CPU(wait_queue_head_t, fscache_object_cong_wait);

/* these values serve as lower bounds, will be adjusted in fscache_init() */
static unsigned fscache_object_max_active = 4;
static unsigned fscache_op_max_active = 2;

#ifdef CONFIG_SYSCTL
static struct ctl_table_header *fscache_sysctl_header;

static int fscache_max_active_sysctl(struct ctl_table *table, int write,
				     void __user *buffer,
				     size_t *lenp, loff_t *ppos)
{
	struct workqueue_struct **wqp = table->extra1;
	unsigned int *datap = table->data;
	int ret;

	ret = proc_dointvec(table, write, buffer, lenp, ppos);
	if (ret == 0)
		workqueue_set_max_active(*wqp, *datap);
	return ret;
}

static struct ctl_table fscache_sysctls[] = {
	{
		.procname	= "object_max_active",
		.data		= &fscache_object_max_active,
		.maxlen		= sizeof(unsigned),
		.mode		= 0644,
		.proc_handler	= fscache_max_active_sysctl,
		.extra1		= &fscache_object_wq,
	},
	{
		.procname	= "operation_max_active",
		.data		= &fscache_op_max_active,
		.maxlen		= sizeof(unsigned),
		.mode		= 0644,
		.proc_handler	= fscache_max_active_sysctl,
		.extra1		= &fscache_op_wq,
	},
	{}
};

static struct ctl_table fscache_sysctls_root[] = {
	{
		.procname	= "fscache",
		.mode		= 0555,
		.child		= fscache_sysctls,
	},
	{}
};
#endif

/*
 * initialise the fs caching module
 */
static int __init fscache_init(void)
{
	unsigned int nr_cpus = num_possible_cpus();
	unsigned int cpu;
	int ret;

	fscache_object_max_active =
		clamp_val(nr_cpus,
			  fscache_object_max_active, WQ_UNBOUND_MAX_ACTIVE);

	ret = -ENOMEM;
	fscache_object_wq = alloc_workqueue("fscache_object", WQ_UNBOUND,
					    fscache_object_max_active);
	if (!fscache_object_wq)
		goto error_object_wq;

	fscache_op_max_active =
		clamp_val(fscache_object_max_active / 2,
			  fscache_op_max_active, WQ_UNBOUND_MAX_ACTIVE);

	ret = -ENOMEM;
	fscache_op_wq = alloc_workqueue("fscache_operation", WQ_UNBOUND,
					fscache_op_max_active);
	if (!fscache_op_wq)
		goto error_op_wq;

	for_each_possible_cpu(cpu)
		init_waitqueue_head(&per_cpu(fscache_object_cong_wait, cpu));

	ret = fscache_proc_init();
	if (ret < 0)
		goto error_proc;

#ifdef CONFIG_SYSCTL
	ret = -ENOMEM;
	fscache_sysctl_header = register_sysctl_table(fscache_sysctls_root);
	if (!fscache_sysctl_header)
		goto error_sysctl;
#endif

	fscache_cookie_jar = kmem_cache_create("fscache_cookie_jar",
					       sizeof(struct fscache_cookie),
					       0,
					       0,
					       fscache_cookie_init_once);
	if (!fscache_cookie_jar) {
		pr_notice("Failed to allocate a cookie jar\n");
		ret = -ENOMEM;
		goto error_cookie_jar;
	}

	fscache_root = kobject_create_and_add("fscache", kernel_kobj);
	if (!fscache_root)
		goto error_kobj;

	pr_notice("Loaded\n");
	return 0;

error_kobj:
	kmem_cache_destroy(fscache_cookie_jar);
error_cookie_jar:
#ifdef CONFIG_SYSCTL
	unregister_sysctl_table(fscache_sysctl_header);
error_sysctl:
#endif
	fscache_proc_cleanup();
error_proc:
	destroy_workqueue(fscache_op_wq);
error_op_wq:
	destroy_workqueue(fscache_object_wq);
error_object_wq:
	return ret;
}

fs_initcall(fscache_init);

/*
 * clean up on module removal
 */
static void __exit fscache_exit(void)
{
	_enter("");

	kobject_put(fscache_root);
	kmem_cache_destroy(fscache_cookie_jar);
#ifdef CONFIG_SYSCTL
	unregister_sysctl_table(fscache_sysctl_header);
#endif
	fscache_proc_cleanup();
	destroy_workqueue(fscache_op_wq);
	destroy_workqueue(fscache_object_wq);
	pr_notice("Unloaded\n");
}

module_exit(fscache_exit);
Commit	Line	Data
06b3db1b DH	1	/* General filesystem local caching manager
	2	*
	3	* Copyright (C) 2004-2007 Red Hat, Inc. All Rights Reserved.
	4	* Written by David Howells (dhowells@redhat.com)
	5	*
	6	* This program is free software; you can redistribute it and/or
	7	* modify it under the terms of the GNU General Public License
	8	* as published by the Free Software Foundation; either version
	9	* 2 of the License, or (at your option) any later version.
	10	*/
	11
	12	#define FSCACHE_DEBUG_LEVEL CACHE
	13	#include <linux/module.h>
	14	#include <linux/init.h>
	15	#include <linux/sched.h>
	16	#include <linux/completion.h>
	17	#include <linux/slab.h>
8b8edefa	18	#include <linux/seq_file.h>
a18feb55	19	#define CREATE_TRACE_POINTS
06b3db1b DH	20	#include "internal.h"
	21
	22	MODULE_DESCRIPTION("FS Cache Manager");
	23	MODULE_AUTHOR("Red Hat, Inc.");
	24	MODULE_LICENSE("GPL");
	25
	26	unsigned fscache_defer_lookup = 1;
	27	module_param_named(defer_lookup, fscache_defer_lookup, uint,
	28	S_IWUSR \| S_IRUGO);
	29	MODULE_PARM_DESC(fscache_defer_lookup,
	30	"Defer cookie lookup to background thread");
	31
	32	unsigned fscache_defer_create = 1;
	33	module_param_named(defer_create, fscache_defer_create, uint,
	34	S_IWUSR \| S_IRUGO);
	35	MODULE_PARM_DESC(fscache_defer_create,
	36	"Defer cookie creation to background thread");
	37
	38	unsigned fscache_debug;
	39	module_param_named(debug, fscache_debug, uint,
	40	S_IWUSR \| S_IRUGO);
	41	MODULE_PARM_DESC(fscache_debug,
	42	"FS-Cache debugging mask");
	43
	44	struct kobject *fscache_root;
8b8edefa	45	struct workqueue_struct *fscache_object_wq;
8af7c124	46	struct workqueue_struct *fscache_op_wq;
8b8edefa TH	47
	48	DEFINE_PER_CPU(wait_queue_head_t, fscache_object_cong_wait);
	49
	50	/* these values serve as lower bounds, will be adjusted in fscache_init() */
	51	static unsigned fscache_object_max_active = 4;
8af7c124	52	static unsigned fscache_op_max_active = 2;
8b8edefa TH	53
	54	#ifdef CONFIG_SYSCTL
	55	static struct ctl_table_header *fscache_sysctl_header;
	56
	57	static int fscache_max_active_sysctl(struct ctl_table *table, int write,
	58	void __user *buffer,
	59	size_t lenp, loff_t ppos)
	60	{
	61	struct workqueue_struct **wqp = table->extra1;
	62	unsigned int *datap = table->data;
	63	int ret;
	64
	65	ret = proc_dointvec(table, write, buffer, lenp, ppos);
	66	if (ret == 0)
	67	workqueue_set_max_active(wqp, datap);
	68	return ret;
	69	}
	70
3e584064	71	static struct ctl_table fscache_sysctls[] = {
8b8edefa TH	72	{
	73	.procname = "object_max_active",
	74	.data = &fscache_object_max_active,
	75	.maxlen = sizeof(unsigned),
	76	.mode = 0644,
	77	.proc_handler = fscache_max_active_sysctl,
	78	.extra1 = &fscache_object_wq,
	79	},
8af7c124 TH	80	{
	81	.procname = "operation_max_active",
	82	.data = &fscache_op_max_active,
	83	.maxlen = sizeof(unsigned),
	84	.mode = 0644,
	85	.proc_handler = fscache_max_active_sysctl,
	86	.extra1 = &fscache_op_wq,
	87	},
8b8edefa TH	88	{}
	89	};
	90
3e584064	91	static struct ctl_table fscache_sysctls_root[] = {
8b8edefa TH	92	{
	93	.procname = "fscache",
	94	.mode = 0555,
	95	.child = fscache_sysctls,
	96	},
	97	{}
	98	};
	99	#endif
06b3db1b DH	100
	101	/*
	102	* initialise the fs caching module
	103	*/
	104	static int __init fscache_init(void)
	105	{
8b8edefa TH	106	unsigned int nr_cpus = num_possible_cpus();
8b8edefa TH	107	unsigned int cpu;
06b3db1b DH	108	int ret;
06b3db1b DH	109
8b8edefa TH	110	fscache_object_max_active =
	111	clamp_val(nr_cpus,
	112	fscache_object_max_active, WQ_UNBOUND_MAX_ACTIVE);
	113
	114	ret = -ENOMEM;
	115	fscache_object_wq = alloc_workqueue("fscache_object", WQ_UNBOUND,
	116	fscache_object_max_active);
	117	if (!fscache_object_wq)
	118	goto error_object_wq;
	119
8af7c124 TH	120	fscache_op_max_active =
	121	clamp_val(fscache_object_max_active / 2,
	122	fscache_op_max_active, WQ_UNBOUND_MAX_ACTIVE);
	123
	124	ret = -ENOMEM;
	125	fscache_op_wq = alloc_workqueue("fscache_operation", WQ_UNBOUND,
	126	fscache_op_max_active);
	127	if (!fscache_op_wq)
	128	goto error_op_wq;
	129
8b8edefa TH	130	for_each_possible_cpu(cpu)
	131	init_waitqueue_head(&per_cpu(fscache_object_cong_wait, cpu));
	132
7394daa8 DH	133	ret = fscache_proc_init();
	134	if (ret < 0)
	135	goto error_proc;
	136
8b8edefa TH	137	#ifdef CONFIG_SYSCTL
	138	ret = -ENOMEM;
	139	fscache_sysctl_header = register_sysctl_table(fscache_sysctls_root);
	140	if (!fscache_sysctl_header)
	141	goto error_sysctl;
	142	#endif
	143
955d0091 DH	144	fscache_cookie_jar = kmem_cache_create("fscache_cookie_jar",
	145	sizeof(struct fscache_cookie),
	146	0,
	147	0,
	148	fscache_cookie_init_once);
	149	if (!fscache_cookie_jar) {
36dfd116	150	pr_notice("Failed to allocate a cookie jar\n");
955d0091 DH	151	ret = -ENOMEM;
	152	goto error_cookie_jar;
	153	}
	154
4c515dd4 DH	155	fscache_root = kobject_create_and_add("fscache", kernel_kobj);
	156	if (!fscache_root)
	157	goto error_kobj;
	158
36dfd116	159	pr_notice("Loaded\n");
06b3db1b DH	160	return 0;
06b3db1b DH	161
4c515dd4	162	error_kobj:
955d0091 DH	163	kmem_cache_destroy(fscache_cookie_jar);
955d0091 DH	164	error_cookie_jar:
8b8edefa TH	165	#ifdef CONFIG_SYSCTL
	166	unregister_sysctl_table(fscache_sysctl_header);
	167	error_sysctl:
	168	#endif
4c515dd4	169	fscache_proc_cleanup();
7394daa8	170	error_proc:
8af7c124 TH	171	destroy_workqueue(fscache_op_wq);
8af7c124 TH	172	error_op_wq:
8b8edefa TH	173	destroy_workqueue(fscache_object_wq);
8b8edefa TH	174	error_object_wq:
06b3db1b DH	175	return ret;
	176	}
	177
	178	fs_initcall(fscache_init);
	179
	180	/*
	181	* clean up on module removal
	182	*/
	183	static void __exit fscache_exit(void)
	184	{
	185	_enter("");
	186
4c515dd4	187	kobject_put(fscache_root);
955d0091	188	kmem_cache_destroy(fscache_cookie_jar);
40f2b6ff	189	#ifdef CONFIG_SYSCTL
8b8edefa	190	unregister_sysctl_table(fscache_sysctl_header);
40f2b6ff	191	#endif
7394daa8	192	fscache_proc_cleanup();
8af7c124	193	destroy_workqueue(fscache_op_wq);
8b8edefa	194	destroy_workqueue(fscache_object_wq);
36dfd116	195	pr_notice("Unloaded\n");
06b3db1b DH	196	}
	197
	198	module_exit(fscache_exit);