From 8b8edefa2fffbff97f9eec8b70e78ae23abad1a0 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Tue, 20 Jul 2010 22:09:01 +0200 Subject: fscache: convert object to use workqueue instead of slow-work Make fscache object state transition callbacks use workqueue instead of slow-work. New dedicated unbound CPU workqueue fscache_object_wq is created. get/put callbacks are renamed and modified to take @object and called directly from the enqueue wrapper and the work function. While at it, make all open coded instances of get/put to use fscache_get/put_object(). * Unbound workqueue is used. * work_busy() output is printed instead of slow-work flags in object debugging outputs. They mean basically the same thing bit-for-bit. * sysctl fscache.object_max_active added to control concurrency. The default value is nr_cpus clamped between 4 and WQ_UNBOUND_MAX_ACTIVE. * slow_work_sleep_till_thread_needed() is replaced with fscache private implementation fscache_object_sleep_till_congested() which waits on fscache_object_wq congestion. * debugfs support is dropped for now. Tracing API based debug facility is planned to be added. Signed-off-by: Tejun Heo Acked-by: David Howells --- fs/fscache/main.c | 76 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 76 insertions(+) (limited to 'fs/fscache/main.c') diff --git a/fs/fscache/main.c b/fs/fscache/main.c index add6bdb53f04..bb8d4c35c7a2 100644 --- a/fs/fscache/main.c +++ b/fs/fscache/main.c @@ -15,6 +15,7 @@ #include #include #include +#include #include "internal.h" MODULE_DESCRIPTION("FS Cache Manager"); @@ -40,22 +41,89 @@ MODULE_PARM_DESC(fscache_debug, "FS-Cache debugging mask"); struct kobject *fscache_root; +struct workqueue_struct *fscache_object_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; + +#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; +} + +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, + }, + {} +}; + +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; ret = slow_work_register_user(THIS_MODULE); if (ret < 0) goto error_slow_work; + 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; + + 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, @@ -78,8 +146,14 @@ static int __init fscache_init(void) 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_object_wq); +error_object_wq: slow_work_unregister_user(THIS_MODULE); error_slow_work: return ret; @@ -96,7 +170,9 @@ static void __exit fscache_exit(void) kobject_put(fscache_root); kmem_cache_destroy(fscache_cookie_jar); + unregister_sysctl_table(fscache_sysctl_header); fscache_proc_cleanup(); + destroy_workqueue(fscache_object_wq); slow_work_unregister_user(THIS_MODULE); printk(KERN_NOTICE "FS-Cache: Unloaded\n"); } -- cgit v1.2.3