[8/9] btrfs: Cleanup the old btrfs workqueue
diff mbox

Message ID 1378889558-21514-9-git-send-email-quwenruo@cn.fujitsu.com
State New, archived
Headers show

Commit Message

Qu Wenruo Sept. 11, 2013, 8:52 a.m. UTC
Since the patches before implemented the new kernel workqueue based
btrfs_worqueue_struct, the old btrfs workqueue(btrfs_worker) can be
removed without any problem.

Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
---
 fs/btrfs/Makefile       |   2 +-
 fs/btrfs/async-thread.c | 714 ------------------------------------------------
 fs/btrfs/async-thread.h | 119 --------
 fs/btrfs/ctree.h        |   3 -
 fs/btrfs/dev-replace.c  |   1 -
 fs/btrfs/disk-io.c      |  24 +-
 fs/btrfs/raid56.c       |   1 -
 fs/btrfs/relocation.c   |   1 -
 fs/btrfs/super.c        |   8 -
 fs/btrfs/volumes.c      |   1 -
 fs/btrfs/volumes.h      |   1 -
 11 files changed, 10 insertions(+), 865 deletions(-)
 delete mode 100644 fs/btrfs/async-thread.c
 delete mode 100644 fs/btrfs/async-thread.h

Comments

Zach Brown Sept. 11, 2013, 5:39 p.m. UTC | #1
On Wed, Sep 11, 2013 at 04:52:37PM +0800, Qu Wenruo wrote:
> Since the patches before implemented the new kernel workqueue based
> btrfs_worqueue_struct, the old btrfs workqueue(btrfs_worker) can be
> removed without any problem.
> 
> Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
> ---
>  fs/btrfs/Makefile       |   2 +-
>  fs/btrfs/async-thread.c | 714 ------------------------------------------------
>  fs/btrfs/async-thread.h | 119 --------
>  fs/btrfs/ctree.h        |   3 -
>  fs/btrfs/dev-replace.c  |   1 -
>  fs/btrfs/disk-io.c      |  24 +-
>  fs/btrfs/raid56.c       |   1 -
>  fs/btrfs/relocation.c   |   1 -
>  fs/btrfs/super.c        |   8 -
>  fs/btrfs/volumes.c      |   1 -
>  fs/btrfs/volumes.h      |   1 -
>  11 files changed, 10 insertions(+), 865 deletions(-)
>  delete mode 100644 fs/btrfs/async-thread.c
>  delete mode 100644 fs/btrfs/async-thread.h

This is exciting.  I'm excited.

> -	worker->task = kthread_run(worker_loop, worker,
> -				   "btrfs-%s-%d", workers->name,
> -				   workers->num_workers + 1);

I bet this simply removes the possibility of the silly problem Eric once
saw where you can have threads with the same name.  (naming things based
on the number of things gives duplicate names if the things are
destroyed and recreated out of order.)

- z
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Patch
diff mbox

diff --git a/fs/btrfs/Makefile b/fs/btrfs/Makefile
index d7439df..e2162af 100644
--- a/fs/btrfs/Makefile
+++ b/fs/btrfs/Makefile
@@ -5,7 +5,7 @@  btrfs-y += super.o ctree.o extent-tree.o print-tree.o root-tree.o dir-item.o \
 	   file-item.o inode-item.o inode-map.o disk-io.o \
 	   transaction.o inode.o file.o tree-defrag.o \
 	   extent_map.o sysfs.o struct-funcs.o xattr.o ordered-data.o \
-	   extent_io.o volumes.o async-thread.o ioctl.o locking.o orphan.o \
+	   extent_io.o volumes.o ioctl.o locking.o orphan.o \
 	   export.o tree-log.o free-space-cache.o zlib.o lzo.o \
 	   compression.o delayed-ref.o relocation.o delayed-inode.o scrub.o \
 	   reada.o backref.o ulist.o qgroup.o send.o dev-replace.o raid56.o \
diff --git a/fs/btrfs/async-thread.c b/fs/btrfs/async-thread.c
deleted file mode 100644
index 58b7d14..0000000
--- a/fs/btrfs/async-thread.c
+++ /dev/null
@@ -1,714 +0,0 @@ 
-/*
- * Copyright (C) 2007 Oracle.  All rights reserved.
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public
- * License v2 as published by the Free Software Foundation.
- *
- * 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., 59 Temple Place - Suite 330,
- * Boston, MA 021110-1307, USA.
- */
-
-#include <linux/kthread.h>
-#include <linux/slab.h>
-#include <linux/list.h>
-#include <linux/spinlock.h>
-#include <linux/freezer.h>
-#include "async-thread.h"
-
-#define WORK_QUEUED_BIT 0
-#define WORK_DONE_BIT 1
-#define WORK_ORDER_DONE_BIT 2
-#define WORK_HIGH_PRIO_BIT 3
-
-/*
- * container for the kthread task pointer and the list of pending work
- * One of these is allocated per thread.
- */
-struct btrfs_worker_thread {
-	/* pool we belong to */
-	struct btrfs_workers *workers;
-
-	/* list of struct btrfs_work that are waiting for service */
-	struct list_head pending;
-	struct list_head prio_pending;
-
-	/* list of worker threads from struct btrfs_workers */
-	struct list_head worker_list;
-
-	/* kthread */
-	struct task_struct *task;
-
-	/* number of things on the pending list */
-	atomic_t num_pending;
-
-	/* reference counter for this struct */
-	atomic_t refs;
-
-	unsigned long sequence;
-
-	/* protects the pending list. */
-	spinlock_t lock;
-
-	/* set to non-zero when this thread is already awake and kicking */
-	int working;
-
-	/* are we currently idle */
-	int idle;
-};
-
-static int __btrfs_start_workers(struct btrfs_workers *workers);
-
-/*
- * btrfs_start_workers uses kthread_run, which can block waiting for memory
- * for a very long time.  It will actually throttle on page writeback,
- * and so it may not make progress until after our btrfs worker threads
- * process all of the pending work structs in their queue
- *
- * This means we can't use btrfs_start_workers from inside a btrfs worker
- * thread that is used as part of cleaning dirty memory, which pretty much
- * involves all of the worker threads.
- *
- * Instead we have a helper queue who never has more than one thread
- * where we scheduler thread start operations.  This worker_start struct
- * is used to contain the work and hold a pointer to the queue that needs
- * another worker.
- */
-struct worker_start {
-	struct btrfs_work work;
-	struct btrfs_workers *queue;
-};
-
-static void start_new_worker_func(struct btrfs_work *work)
-{
-	struct worker_start *start;
-	start = container_of(work, struct worker_start, work);
-	__btrfs_start_workers(start->queue);
-	kfree(start);
-}
-
-/*
- * helper function to move a thread onto the idle list after it
- * has finished some requests.
- */
-static void check_idle_worker(struct btrfs_worker_thread *worker)
-{
-	if (!worker->idle && atomic_read(&worker->num_pending) <
-	    worker->workers->idle_thresh / 2) {
-		unsigned long flags;
-		spin_lock_irqsave(&worker->workers->lock, flags);
-		worker->idle = 1;
-
-		/* the list may be empty if the worker is just starting */
-		if (!list_empty(&worker->worker_list)) {
-			list_move(&worker->worker_list,
-				 &worker->workers->idle_list);
-		}
-		spin_unlock_irqrestore(&worker->workers->lock, flags);
-	}
-}
-
-/*
- * helper function to move a thread off the idle list after new
- * pending work is added.
- */
-static void check_busy_worker(struct btrfs_worker_thread *worker)
-{
-	if (worker->idle && atomic_read(&worker->num_pending) >=
-	    worker->workers->idle_thresh) {
-		unsigned long flags;
-		spin_lock_irqsave(&worker->workers->lock, flags);
-		worker->idle = 0;
-
-		if (!list_empty(&worker->worker_list)) {
-			list_move_tail(&worker->worker_list,
-				      &worker->workers->worker_list);
-		}
-		spin_unlock_irqrestore(&worker->workers->lock, flags);
-	}
-}
-
-static void check_pending_worker_creates(struct btrfs_worker_thread *worker)
-{
-	struct btrfs_workers *workers = worker->workers;
-	struct worker_start *start;
-	unsigned long flags;
-
-	rmb();
-	if (!workers->atomic_start_pending)
-		return;
-
-	start = kzalloc(sizeof(*start), GFP_NOFS);
-	if (!start)
-		return;
-
-	start->work.func = start_new_worker_func;
-	start->queue = workers;
-
-	spin_lock_irqsave(&workers->lock, flags);
-	if (!workers->atomic_start_pending)
-		goto out;
-
-	workers->atomic_start_pending = 0;
-	if (workers->num_workers + workers->num_workers_starting >=
-	    workers->max_workers)
-		goto out;
-
-	workers->num_workers_starting += 1;
-	spin_unlock_irqrestore(&workers->lock, flags);
-	btrfs_queue_worker(workers->atomic_worker_start, &start->work);
-	return;
-
-out:
-	kfree(start);
-	spin_unlock_irqrestore(&workers->lock, flags);
-}
-
-static noinline void run_ordered_completions(struct btrfs_workers *workers,
-					    struct btrfs_work *work)
-{
-	if (!workers->ordered)
-		return;
-
-	set_bit(WORK_DONE_BIT, &work->flags);
-
-	spin_lock(&workers->order_lock);
-
-	while (1) {
-		if (!list_empty(&workers->prio_order_list)) {
-			work = list_entry(workers->prio_order_list.next,
-					  struct btrfs_work, order_list);
-		} else if (!list_empty(&workers->order_list)) {
-			work = list_entry(workers->order_list.next,
-					  struct btrfs_work, order_list);
-		} else {
-			break;
-		}
-		if (!test_bit(WORK_DONE_BIT, &work->flags))
-			break;
-
-		/* we are going to call the ordered done function, but
-		 * we leave the work item on the list as a barrier so
-		 * that later work items that are done don't have their
-		 * functions called before this one returns
-		 */
-		if (test_and_set_bit(WORK_ORDER_DONE_BIT, &work->flags))
-			break;
-
-		spin_unlock(&workers->order_lock);
-
-		work->ordered_func(work);
-
-		/* now take the lock again and drop our item from the list */
-		spin_lock(&workers->order_lock);
-		list_del(&work->order_list);
-		spin_unlock(&workers->order_lock);
-
-		/*
-		 * we don't want to call the ordered free functions
-		 * with the lock held though
-		 */
-		work->ordered_free(work);
-		spin_lock(&workers->order_lock);
-	}
-
-	spin_unlock(&workers->order_lock);
-}
-
-static void put_worker(struct btrfs_worker_thread *worker)
-{
-	if (atomic_dec_and_test(&worker->refs))
-		kfree(worker);
-}
-
-static int try_worker_shutdown(struct btrfs_worker_thread *worker)
-{
-	int freeit = 0;
-
-	spin_lock_irq(&worker->lock);
-	spin_lock(&worker->workers->lock);
-	if (worker->workers->num_workers > 1 &&
-	    worker->idle &&
-	    !worker->working &&
-	    !list_empty(&worker->worker_list) &&
-	    list_empty(&worker->prio_pending) &&
-	    list_empty(&worker->pending) &&
-	    atomic_read(&worker->num_pending) == 0) {
-		freeit = 1;
-		list_del_init(&worker->worker_list);
-		worker->workers->num_workers--;
-	}
-	spin_unlock(&worker->workers->lock);
-	spin_unlock_irq(&worker->lock);
-
-	if (freeit)
-		put_worker(worker);
-	return freeit;
-}
-
-static struct btrfs_work *get_next_work(struct btrfs_worker_thread *worker,
-					struct list_head *prio_head,
-					struct list_head *head)
-{
-	struct btrfs_work *work = NULL;
-	struct list_head *cur = NULL;
-
-	if(!list_empty(prio_head))
-		cur = prio_head->next;
-
-	smp_mb();
-	if (!list_empty(&worker->prio_pending))
-		goto refill;
-
-	if (!list_empty(head))
-		cur = head->next;
-
-	if (cur)
-		goto out;
-
-refill:
-	spin_lock_irq(&worker->lock);
-	list_splice_tail_init(&worker->prio_pending, prio_head);
-	list_splice_tail_init(&worker->pending, head);
-
-	if (!list_empty(prio_head))
-		cur = prio_head->next;
-	else if (!list_empty(head))
-		cur = head->next;
-	spin_unlock_irq(&worker->lock);
-
-	if (!cur)
-		goto out_fail;
-
-out:
-	work = list_entry(cur, struct btrfs_work, list);
-
-out_fail:
-	return work;
-}
-
-/*
- * main loop for servicing work items
- */
-static int worker_loop(void *arg)
-{
-	struct btrfs_worker_thread *worker = arg;
-	struct list_head head;
-	struct list_head prio_head;
-	struct btrfs_work *work;
-
-	INIT_LIST_HEAD(&head);
-	INIT_LIST_HEAD(&prio_head);
-
-	do {
-again:
-		while (1) {
-
-
-			work = get_next_work(worker, &prio_head, &head);
-			if (!work)
-				break;
-
-			list_del(&work->list);
-			clear_bit(WORK_QUEUED_BIT, &work->flags);
-
-			work->worker = worker;
-
-			work->func(work);
-
-			atomic_dec(&worker->num_pending);
-			/*
-			 * unless this is an ordered work queue,
-			 * 'work' was probably freed by func above.
-			 */
-			run_ordered_completions(worker->workers, work);
-
-			check_pending_worker_creates(worker);
-			cond_resched();
-		}
-
-		spin_lock_irq(&worker->lock);
-		check_idle_worker(worker);
-
-		if (freezing(current)) {
-			worker->working = 0;
-			spin_unlock_irq(&worker->lock);
-			try_to_freeze();
-		} else {
-			spin_unlock_irq(&worker->lock);
-			if (!kthread_should_stop()) {
-				cpu_relax();
-				/*
-				 * we've dropped the lock, did someone else
-				 * jump_in?
-				 */
-				smp_mb();
-				if (!list_empty(&worker->pending) ||
-				    !list_empty(&worker->prio_pending))
-					continue;
-
-				/*
-				 * this short schedule allows more work to
-				 * come in without the queue functions
-				 * needing to go through wake_up_process()
-				 *
-				 * worker->working is still 1, so nobody
-				 * is going to try and wake us up
-				 */
-				schedule_timeout(1);
-				smp_mb();
-				if (!list_empty(&worker->pending) ||
-				    !list_empty(&worker->prio_pending))
-					continue;
-
-				if (kthread_should_stop())
-					break;
-
-				/* still no more work?, sleep for real */
-				spin_lock_irq(&worker->lock);
-				set_current_state(TASK_INTERRUPTIBLE);
-				if (!list_empty(&worker->pending) ||
-				    !list_empty(&worker->prio_pending)) {
-					spin_unlock_irq(&worker->lock);
-					set_current_state(TASK_RUNNING);
-					goto again;
-				}
-
-				/*
-				 * this makes sure we get a wakeup when someone
-				 * adds something new to the queue
-				 */
-				worker->working = 0;
-				spin_unlock_irq(&worker->lock);
-
-				if (!kthread_should_stop()) {
-					schedule_timeout(HZ * 120);
-					if (!worker->working &&
-					    try_worker_shutdown(worker)) {
-						return 0;
-					}
-				}
-			}
-			__set_current_state(TASK_RUNNING);
-		}
-	} while (!kthread_should_stop());
-	return 0;
-}
-
-/*
- * this will wait for all the worker threads to shutdown
- */
-void btrfs_stop_workers(struct btrfs_workers *workers)
-{
-	struct list_head *cur;
-	struct btrfs_worker_thread *worker;
-	int can_stop;
-
-	spin_lock_irq(&workers->lock);
-	list_splice_init(&workers->idle_list, &workers->worker_list);
-	while (!list_empty(&workers->worker_list)) {
-		cur = workers->worker_list.next;
-		worker = list_entry(cur, struct btrfs_worker_thread,
-				    worker_list);
-
-		atomic_inc(&worker->refs);
-		workers->num_workers -= 1;
-		if (!list_empty(&worker->worker_list)) {
-			list_del_init(&worker->worker_list);
-			put_worker(worker);
-			can_stop = 1;
-		} else
-			can_stop = 0;
-		spin_unlock_irq(&workers->lock);
-		if (can_stop)
-			kthread_stop(worker->task);
-		spin_lock_irq(&workers->lock);
-		put_worker(worker);
-	}
-	spin_unlock_irq(&workers->lock);
-}
-
-/*
- * simple init on struct btrfs_workers
- */
-void btrfs_init_workers(struct btrfs_workers *workers, char *name, int max,
-			struct btrfs_workers *async_helper)
-{
-	workers->num_workers = 0;
-	workers->num_workers_starting = 0;
-	INIT_LIST_HEAD(&workers->worker_list);
-	INIT_LIST_HEAD(&workers->idle_list);
-	INIT_LIST_HEAD(&workers->order_list);
-	INIT_LIST_HEAD(&workers->prio_order_list);
-	spin_lock_init(&workers->lock);
-	spin_lock_init(&workers->order_lock);
-	workers->max_workers = max;
-	workers->idle_thresh = 32;
-	workers->name = name;
-	workers->ordered = 0;
-	workers->atomic_start_pending = 0;
-	workers->atomic_worker_start = async_helper;
-}
-
-/*
- * starts new worker threads.  This does not enforce the max worker
- * count in case you need to temporarily go past it.
- */
-static int __btrfs_start_workers(struct btrfs_workers *workers)
-{
-	struct btrfs_worker_thread *worker;
-	int ret = 0;
-
-	worker = kzalloc(sizeof(*worker), GFP_NOFS);
-	if (!worker) {
-		ret = -ENOMEM;
-		goto fail;
-	}
-
-	INIT_LIST_HEAD(&worker->pending);
-	INIT_LIST_HEAD(&worker->prio_pending);
-	INIT_LIST_HEAD(&worker->worker_list);
-	spin_lock_init(&worker->lock);
-
-	atomic_set(&worker->num_pending, 0);
-	atomic_set(&worker->refs, 1);
-	worker->workers = workers;
-	worker->task = kthread_run(worker_loop, worker,
-				   "btrfs-%s-%d", workers->name,
-				   workers->num_workers + 1);
-	if (IS_ERR(worker->task)) {
-		ret = PTR_ERR(worker->task);
-		kfree(worker);
-		goto fail;
-	}
-	spin_lock_irq(&workers->lock);
-	list_add_tail(&worker->worker_list, &workers->idle_list);
-	worker->idle = 1;
-	workers->num_workers++;
-	workers->num_workers_starting--;
-	WARN_ON(workers->num_workers_starting < 0);
-	spin_unlock_irq(&workers->lock);
-
-	return 0;
-fail:
-	spin_lock_irq(&workers->lock);
-	workers->num_workers_starting--;
-	spin_unlock_irq(&workers->lock);
-	return ret;
-}
-
-int btrfs_start_workers(struct btrfs_workers *workers)
-{
-	spin_lock_irq(&workers->lock);
-	workers->num_workers_starting++;
-	spin_unlock_irq(&workers->lock);
-	return __btrfs_start_workers(workers);
-}
-
-/*
- * run through the list and find a worker thread that doesn't have a lot
- * to do right now.  This can return null if we aren't yet at the thread
- * count limit and all of the threads are busy.
- */
-static struct btrfs_worker_thread *next_worker(struct btrfs_workers *workers)
-{
-	struct btrfs_worker_thread *worker;
-	struct list_head *next;
-	int enforce_min;
-
-	enforce_min = (workers->num_workers + workers->num_workers_starting) <
-		workers->max_workers;
-
-	/*
-	 * if we find an idle thread, don't move it to the end of the
-	 * idle list.  This improves the chance that the next submission
-	 * will reuse the same thread, and maybe catch it while it is still
-	 * working
-	 */
-	if (!list_empty(&workers->idle_list)) {
-		next = workers->idle_list.next;
-		worker = list_entry(next, struct btrfs_worker_thread,
-				    worker_list);
-		return worker;
-	}
-	if (enforce_min || list_empty(&workers->worker_list))
-		return NULL;
-
-	/*
-	 * if we pick a busy task, move the task to the end of the list.
-	 * hopefully this will keep things somewhat evenly balanced.
-	 * Do the move in batches based on the sequence number.  This groups
-	 * requests submitted at roughly the same time onto the same worker.
-	 */
-	next = workers->worker_list.next;
-	worker = list_entry(next, struct btrfs_worker_thread, worker_list);
-	worker->sequence++;
-
-	if (worker->sequence % workers->idle_thresh == 0)
-		list_move_tail(next, &workers->worker_list);
-	return worker;
-}
-
-/*
- * selects a worker thread to take the next job.  This will either find
- * an idle worker, start a new worker up to the max count, or just return
- * one of the existing busy workers.
- */
-static struct btrfs_worker_thread *find_worker(struct btrfs_workers *workers)
-{
-	struct btrfs_worker_thread *worker;
-	unsigned long flags;
-	struct list_head *fallback;
-	int ret;
-
-	spin_lock_irqsave(&workers->lock, flags);
-again:
-	worker = next_worker(workers);
-
-	if (!worker) {
-		if (workers->num_workers + workers->num_workers_starting >=
-		    workers->max_workers) {
-			goto fallback;
-		} else if (workers->atomic_worker_start) {
-			workers->atomic_start_pending = 1;
-			goto fallback;
-		} else {
-			workers->num_workers_starting++;
-			spin_unlock_irqrestore(&workers->lock, flags);
-			/* we're below the limit, start another worker */
-			ret = __btrfs_start_workers(workers);
-			spin_lock_irqsave(&workers->lock, flags);
-			if (ret)
-				goto fallback;
-			goto again;
-		}
-	}
-	goto found;
-
-fallback:
-	fallback = NULL;
-	/*
-	 * we have failed to find any workers, just
-	 * return the first one we can find.
-	 */
-	if (!list_empty(&workers->worker_list))
-		fallback = workers->worker_list.next;
-	if (!list_empty(&workers->idle_list))
-		fallback = workers->idle_list.next;
-	BUG_ON(!fallback);
-	worker = list_entry(fallback,
-		  struct btrfs_worker_thread, worker_list);
-found:
-	/*
-	 * this makes sure the worker doesn't exit before it is placed
-	 * onto a busy/idle list
-	 */
-	atomic_inc(&worker->num_pending);
-	spin_unlock_irqrestore(&workers->lock, flags);
-	return worker;
-}
-
-/*
- * btrfs_requeue_work just puts the work item back on the tail of the list
- * it was taken from.  It is intended for use with long running work functions
- * that make some progress and want to give the cpu up for others.
- */
-void btrfs_requeue_work(struct btrfs_work *work)
-{
-	struct btrfs_worker_thread *worker = work->worker;
-	unsigned long flags;
-	int wake = 0;
-
-	if (test_and_set_bit(WORK_QUEUED_BIT, &work->flags))
-		return;
-
-	spin_lock_irqsave(&worker->lock, flags);
-	if (test_bit(WORK_HIGH_PRIO_BIT, &work->flags))
-		list_add_tail(&work->list, &worker->prio_pending);
-	else
-		list_add_tail(&work->list, &worker->pending);
-	atomic_inc(&worker->num_pending);
-
-	/* by definition we're busy, take ourselves off the idle
-	 * list
-	 */
-	if (worker->idle) {
-		spin_lock(&worker->workers->lock);
-		worker->idle = 0;
-		list_move_tail(&worker->worker_list,
-			      &worker->workers->worker_list);
-		spin_unlock(&worker->workers->lock);
-	}
-	if (!worker->working) {
-		wake = 1;
-		worker->working = 1;
-	}
-
-	if (wake)
-		wake_up_process(worker->task);
-	spin_unlock_irqrestore(&worker->lock, flags);
-}
-
-void btrfs_set_work_high_prio(struct btrfs_work *work)
-{
-	set_bit(WORK_HIGH_PRIO_BIT, &work->flags);
-}
-
-/*
- * places a struct btrfs_work into the pending queue of one of the kthreads
- */
-void btrfs_queue_worker(struct btrfs_workers *workers, struct btrfs_work *work)
-{
-	struct btrfs_worker_thread *worker;
-	unsigned long flags;
-	int wake = 0;
-
-	/* don't requeue something already on a list */
-	if (test_and_set_bit(WORK_QUEUED_BIT, &work->flags))
-		return;
-
-	worker = find_worker(workers);
-	if (workers->ordered) {
-		/*
-		 * you're not allowed to do ordered queues from an
-		 * interrupt handler
-		 */
-		spin_lock(&workers->order_lock);
-		if (test_bit(WORK_HIGH_PRIO_BIT, &work->flags)) {
-			list_add_tail(&work->order_list,
-				      &workers->prio_order_list);
-		} else {
-			list_add_tail(&work->order_list, &workers->order_list);
-		}
-		spin_unlock(&workers->order_lock);
-	} else {
-		INIT_LIST_HEAD(&work->order_list);
-	}
-
-	spin_lock_irqsave(&worker->lock, flags);
-
-	if (test_bit(WORK_HIGH_PRIO_BIT, &work->flags))
-		list_add_tail(&work->list, &worker->prio_pending);
-	else
-		list_add_tail(&work->list, &worker->pending);
-	check_busy_worker(worker);
-
-	/*
-	 * avoid calling into wake_up_process if this thread has already
-	 * been kicked
-	 */
-	if (!worker->working)
-		wake = 1;
-	worker->working = 1;
-
-	if (wake)
-		wake_up_process(worker->task);
-	spin_unlock_irqrestore(&worker->lock, flags);
-}
diff --git a/fs/btrfs/async-thread.h b/fs/btrfs/async-thread.h
deleted file mode 100644
index 063698b..0000000
--- a/fs/btrfs/async-thread.h
+++ /dev/null
@@ -1,119 +0,0 @@ 
-/*
- * Copyright (C) 2007 Oracle.  All rights reserved.
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public
- * License v2 as published by the Free Software Foundation.
- *
- * 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., 59 Temple Place - Suite 330,
- * Boston, MA 021110-1307, USA.
- */
-
-#ifndef __BTRFS_ASYNC_THREAD_
-#define __BTRFS_ASYNC_THREAD_
-
-struct btrfs_worker_thread;
-
-/*
- * This is similar to a workqueue, but it is meant to spread the operations
- * across all available cpus instead of just the CPU that was used to
- * queue the work.  There is also some batching introduced to try and
- * cut down on context switches.
- *
- * By default threads are added on demand up to 2 * the number of cpus.
- * Changing struct btrfs_workers->max_workers is one way to prevent
- * demand creation of kthreads.
- *
- * the basic model of these worker threads is to embed a btrfs_work
- * structure in your own data struct, and use container_of in a
- * work function to get back to your data struct.
- */
-struct btrfs_work {
-	/*
-	 * func should be set to the function you want called
-	 * your work struct is passed as the only arg
-	 *
-	 * ordered_func must be set for work sent to an ordered work queue,
-	 * and it is called to complete a given work item in the same
-	 * order they were sent to the queue.
-	 */
-	void (*func)(struct btrfs_work *work);
-	void (*ordered_func)(struct btrfs_work *work);
-	void (*ordered_free)(struct btrfs_work *work);
-
-	/*
-	 * flags should be set to zero.  It is used to make sure the
-	 * struct is only inserted once into the list.
-	 */
-	unsigned long flags;
-
-	/* don't touch these */
-	struct btrfs_worker_thread *worker;
-	struct list_head list;
-	struct list_head order_list;
-};
-
-struct btrfs_workers {
-	/* current number of running workers */
-	int num_workers;
-
-	int num_workers_starting;
-
-	/* max number of workers allowed.  changed by btrfs_start_workers */
-	int max_workers;
-
-	/* once a worker has this many requests or fewer, it is idle */
-	int idle_thresh;
-
-	/* force completions in the order they were queued */
-	int ordered;
-
-	/* more workers required, but in an interrupt handler */
-	int atomic_start_pending;
-
-	/*
-	 * are we allowed to sleep while starting workers or are we required
-	 * to start them at a later time?  If we can't sleep, this indicates
-	 * which queue we need to use to schedule thread creation.
-	 */
-	struct btrfs_workers *atomic_worker_start;
-
-	/* list with all the work threads.  The workers on the idle thread
-	 * may be actively servicing jobs, but they haven't yet hit the
-	 * idle thresh limit above.
-	 */
-	struct list_head worker_list;
-	struct list_head idle_list;
-
-	/*
-	 * when operating in ordered mode, this maintains the list
-	 * of work items waiting for completion
-	 */
-	struct list_head order_list;
-	struct list_head prio_order_list;
-
-	/* lock for finding the next worker thread to queue on */
-	spinlock_t lock;
-
-	/* lock for the ordered lists */
-	spinlock_t order_lock;
-
-	/* extra name for this worker, used for current->name */
-	char *name;
-};
-
-void btrfs_queue_worker(struct btrfs_workers *workers, struct btrfs_work *work);
-int btrfs_start_workers(struct btrfs_workers *workers);
-void btrfs_stop_workers(struct btrfs_workers *workers);
-void btrfs_init_workers(struct btrfs_workers *workers, char *name, int max,
-			struct btrfs_workers *async_starter);
-void btrfs_requeue_work(struct btrfs_work *work);
-void btrfs_set_work_high_prio(struct btrfs_work *work);
-#endif
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 0cf4320..399e85b 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -34,7 +34,6 @@ 
 #include <linux/btrfs.h>
 #include "extent_io.h"
 #include "extent_map.h"
-#include "async-thread.h"
 
 struct btrfs_trans_handle;
 struct btrfs_transaction;
@@ -1476,8 +1475,6 @@  struct btrfs_fs_info {
 	 * A third pool does submit_bio to avoid deadlocking with the other
 	 * two
 	 */
-	struct btrfs_workers generic_worker;
-
 	struct btrfs_workqueue_struct *workers;
 	struct btrfs_workqueue_struct *delalloc_workers;
 	struct workqueue_struct *submit_workers;
diff --git a/fs/btrfs/dev-replace.c b/fs/btrfs/dev-replace.c
index 4253ad5..9323126 100644
--- a/fs/btrfs/dev-replace.c
+++ b/fs/btrfs/dev-replace.c
@@ -33,7 +33,6 @@ 
 #include "transaction.h"
 #include "print-tree.h"
 #include "volumes.h"
-#include "async-thread.h"
 #include "check-integrity.h"
 #include "rcu-string.h"
 #include "dev-replace.h"
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 97df233..a61e1fe 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -39,7 +39,6 @@ 
 #include "btrfs_inode.h"
 #include "volumes.h"
 #include "print-tree.h"
-#include "async-thread.h"
 #include "locking.h"
 #include "tree-log.h"
 #include "free-space-cache.h"
@@ -1984,7 +1983,6 @@  static noinline int next_root_backup(struct btrfs_fs_info *info,
 /* helper to cleanup workers */
 static void btrfs_stop_all_workers(struct btrfs_fs_info *fs_info)
 {
-	btrfs_stop_workers(&fs_info->generic_worker);
 	btrfs_destroy_workqueue(fs_info->delalloc_workers);
 	btrfs_destroy_workqueue(fs_info->workers);
 	destroy_workqueue(fs_info->submit_workers);
@@ -2458,8 +2456,6 @@  int open_ctree(struct super_block *sb,
 	}
 
 	max_active = fs_info->thread_pool_size;
-	btrfs_init_workers(&fs_info->generic_worker,
-			   "genwork", 1, NULL);
 
 	fs_info->workers = btrfs_alloc_workqueue("worker", "worker-ordered",
 						 "worker-high", max_active);
@@ -2497,17 +2493,15 @@  int open_ctree(struct super_block *sb,
 	 * btrfs_start_workers can really only fail because of ENOMEM so just
 	 * return -ENOMEM if any of these fail.
 	 */
-	ret = btrfs_start_workers(&fs_info->generic_worker);
-
-	if (ret || !(fs_info->flush_workers && fs_info->endio_workers &&
-		     fs_info->endio_meta_workers && fs_info->workers &&
-		     fs_info->submit_workers &&
-		     fs_info->endio_raid56_workers &&
-		     fs_info->rmw_workers && fs_info->delalloc_workers &&
-		     fs_info->endio_meta_write_workers &&
-		     fs_info->endio_write_workers &&
-		     fs_info->caching_workers && fs_info->readahead_workers &&
-		     fs_info->fixup_workers && fs_info->delayed_workers)) {
+
+	if (!(fs_info->flush_workers && fs_info->endio_workers &&
+	      fs_info->endio_meta_workers && fs_info->workers &&
+	      fs_info->submit_workers && fs_info->endio_raid56_workers &&
+	      fs_info->rmw_workers && fs_info->delalloc_workers &&
+	      fs_info->endio_meta_write_workers &&
+	      fs_info->endio_write_workers && fs_info->caching_workers &&
+	      fs_info->readahead_workers && fs_info->fixup_workers &&
+	      fs_info->delayed_workers)) {
 		err = -ENOMEM;
 		goto fail_sb_buffer;
 	}
diff --git a/fs/btrfs/raid56.c b/fs/btrfs/raid56.c
index 4b7769d..04f3d5e 100644
--- a/fs/btrfs/raid56.c
+++ b/fs/btrfs/raid56.c
@@ -41,7 +41,6 @@ 
 #include "print-tree.h"
 #include "volumes.h"
 #include "raid56.h"
-#include "async-thread.h"
 #include "check-integrity.h"
 #include "rcu-string.h"
 
diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index 1209649..16b6db0 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -28,7 +28,6 @@ 
 #include "volumes.h"
 #include "locking.h"
 #include "btrfs_inode.h"
-#include "async-thread.h"
 #include "free-space-cache.h"
 #include "inode-map.h"
 
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 402b488..63e653c 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -1156,13 +1156,6 @@  error_fs_info:
 	return ERR_PTR(error);
 }
 
-static void btrfs_set_max_workers(struct btrfs_workers *workers, int new_limit)
-{
-	spin_lock_irq(&workers->lock);
-	workers->max_workers = new_limit;
-	spin_unlock_irq(&workers->lock);
-}
-
 static void btrfs_resize_thread_pool(struct btrfs_fs_info *fs_info,
 				     int new_pool_size, int old_pool_size)
 {
@@ -1174,7 +1167,6 @@  static void btrfs_resize_thread_pool(struct btrfs_fs_info *fs_info,
 	printk(KERN_INFO "btrfs: resize thread pool %d -> %d\n",
 	       old_pool_size, new_pool_size);
 
-	btrfs_set_max_workers(&fs_info->generic_worker, new_pool_size);
 	btrfs_workqueue_set_max(fs_info->workers, new_pool_size);
 	btrfs_workqueue_set_max(fs_info->delalloc_workers, new_pool_size);
 	workqueue_set_max_active(fs_info->submit_workers, new_pool_size);
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index cb10e02..69c0661 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -35,7 +35,6 @@ 
 #include "print-tree.h"
 #include "volumes.h"
 #include "raid56.h"
-#include "async-thread.h"
 #include "check-integrity.h"
 #include "rcu-string.h"
 #include "math.h"
diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index bd849cc..0efb041 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -22,7 +22,6 @@ 
 #include <linux/bio.h>
 #include <linux/sort.h>
 #include <linux/btrfs.h>
-#include "async-thread.h"
 
 #define BTRFS_STRIPE_LEN	(64 * 1024)