diff options
Diffstat (limited to 'fs/fscache/main.c')
| -rw-r--r-- | fs/fscache/main.c | 206 |
1 files changed, 206 insertions, 0 deletions
diff --git a/fs/fscache/main.c b/fs/fscache/main.c new file mode 100644 index 000000000..b39d487cc --- /dev/null +++ b/fs/fscache/main.c @@ -0,0 +1,206 @@ +/* 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> +#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); + +/* + * wait_on_atomic_t() sleep function for uninterruptible waiting + */ +int fscache_wait_atomic_t(atomic_t *p) +{ + schedule(); + return 0; +} |