diff options
Diffstat (limited to 'kernel/async.c')
| -rw-r--r-- | kernel/async.c | 141 |
1 files changed, 22 insertions, 119 deletions
diff --git a/kernel/async.c b/kernel/async.c index 15319d6..cd9dbb9 100644 --- a/kernel/async.c +++ b/kernel/async.c @@ -49,40 +49,33 @@ asynchronous and synchronous parts of the kernel. */ #include <linux/async.h> -#include <linux/bug.h> #include <linux/module.h> #include <linux/wait.h> #include <linux/sched.h> -#include <linux/init.h> -#include <linux/kthread.h> -#include <linux/delay.h> #include <linux/slab.h> +#include <linux/workqueue.h> #include <asm/atomic.h> static async_cookie_t next_cookie = 1; -#define MAX_THREADS 256 #define MAX_WORK 32768 static LIST_HEAD(async_pending); static LIST_HEAD(async_running); static DEFINE_SPINLOCK(async_lock); -static int async_enabled = 0; - struct async_entry { - struct list_head list; - async_cookie_t cookie; - async_func_ptr *func; - void *data; - struct list_head *running; + struct list_head list; + struct work_struct work; + async_cookie_t cookie; + async_func_ptr *func; + void *data; + struct list_head *running; }; static DECLARE_WAIT_QUEUE_HEAD(async_done); -static DECLARE_WAIT_QUEUE_HEAD(async_new); static atomic_t entry_count; -static atomic_t thread_count; extern int initcall_debug; @@ -117,27 +110,23 @@ static async_cookie_t lowest_in_progress(struct list_head *running) spin_unlock_irqrestore(&async_lock, flags); return ret; } + /* * pick the first pending entry and run it */ -static void run_one_entry(void) +static void async_run_entry_fn(struct work_struct *work) { + struct async_entry *entry = + container_of(work, struct async_entry, work); unsigned long flags; - struct async_entry *entry; ktime_t calltime, delta, rettime; - /* 1) pick one task from the pending queue */ - + /* 1) move self to the running queue */ spin_lock_irqsave(&async_lock, flags); - if (list_empty(&async_pending)) - goto out; - entry = list_first_entry(&async_pending, struct async_entry, list); - - /* 2) move it to the running queue */ list_move_tail(&entry->list, entry->running); spin_unlock_irqrestore(&async_lock, flags); - /* 3) run it (and print duration)*/ + /* 2) run (and print duration) */ if (initcall_debug && system_state == SYSTEM_BOOTING) { printk("calling %lli_%pF @ %i\n", (long long)entry->cookie, entry->func, task_pid_nr(current)); @@ -153,31 +142,25 @@ static void run_one_entry(void) (long long)ktime_to_ns(delta) >> 10); } - /* 4) remove it from the running queue */ + /* 3) remove self from the running queue */ spin_lock_irqsave(&async_lock, flags); list_del(&entry->list); - /* 5) free the entry */ + /* 4) free the entry */ kfree(entry); atomic_dec(&entry_count); spin_unlock_irqrestore(&async_lock, flags); - /* 6) wake up any waiters. */ + /* 5) wake up any waiters */ wake_up(&async_done); - return; - -out: - spin_unlock_irqrestore(&async_lock, flags); } - static async_cookie_t __async_schedule(async_func_ptr *ptr, void *data, struct list_head *running) { struct async_entry *entry; unsigned long flags; async_cookie_t newcookie; - /* allow irq-off callers */ entry = kzalloc(sizeof(struct async_entry), GFP_ATOMIC); @@ -186,7 +169,7 @@ static async_cookie_t __async_schedule(async_func_ptr *ptr, void *data, struct l * If we're out of memory or if there's too much work * pending already, we execute synchronously. */ - if (!async_enabled || !entry || atomic_read(&entry_count) > MAX_WORK) { + if (!entry || atomic_read(&entry_count) > MAX_WORK) { kfree(entry); spin_lock_irqsave(&async_lock, flags); newcookie = next_cookie++; @@ -196,6 +179,7 @@ static async_cookie_t __async_schedule(async_func_ptr *ptr, void *data, struct l ptr(data, newcookie); return newcookie; } + INIT_WORK(&entry->work, async_run_entry_fn); entry->func = ptr; entry->data = data; entry->running = running; @@ -205,7 +189,10 @@ static async_cookie_t __async_schedule(async_func_ptr *ptr, void *data, struct l list_add_tail(&entry->list, &async_pending); atomic_inc(&entry_count); spin_unlock_irqrestore(&async_lock, flags); - wake_up(&async_new); + + /* schedule for execution */ + queue_work(system_unbound_wq, &entry->work); + return newcookie; } @@ -312,87 +299,3 @@ void async_synchronize_cookie(async_cookie_t cookie) async_synchronize_cookie_domain(cookie, &async_running); } EXPORT_SYMBOL_GPL(async_synchronize_cookie); - - -static int async_thread(void *unused) -{ - DECLARE_WAITQUEUE(wq, current); - add_wait_queue(&async_new, &wq); - - while (!kthread_should_stop()) { - int ret = HZ; - set_current_state(TASK_INTERRUPTIBLE); - /* - * check the list head without lock.. false positives - * are dealt with inside run_one_entry() while holding - * the lock. - */ - rmb(); - if (!list_empty(&async_pending)) - run_one_entry(); - else - ret = schedule_timeout(HZ); - - if (ret == 0) { - /* - * we timed out, this means we as thread are redundant. - * we sign off and die, but we to avoid any races there - * is a last-straw check to see if work snuck in. - */ - atomic_dec(&thread_count); - wmb(); /* manager must see our departure first */ - if (list_empty(&async_pending)) - break; - /* - * woops work came in between us timing out and us - * signing off; we need to stay alive and keep working. - */ - atomic_inc(&thread_count); - } - } - remove_wait_queue(&async_new, &wq); - - return 0; -} - -static int async_manager_thread(void *unused) -{ - DECLARE_WAITQUEUE(wq, current); - add_wait_queue(&async_new, &wq); - - while (!kthread_should_stop()) { - int tc, ec; - - set_current_state(TASK_INTERRUPTIBLE); - - tc = atomic_read(&thread_count); - rmb(); - ec = atomic_read(&entry_count); - - while (tc < ec && tc < MAX_THREADS) { - if (IS_ERR(kthread_run(async_thread, NULL, "async/%i", - tc))) { - msleep(100); - continue; - } - atomic_inc(&thread_count); - tc++; - } - - schedule(); - } - remove_wait_queue(&async_new, &wq); - - return 0; -} - -static int __init async_init(void) -{ - async_enabled = - !IS_ERR(kthread_run(async_manager_thread, NULL, "async/mgr")); - - WARN_ON(!async_enabled); - return 0; -} - -core_initcall(async_init); |
