[PATCH v5 00/18] Replace btrfs_workers with kernel workqueue based btrfs_workqueue

[PATCH v5 00/18] Replace btrfs_workers with kernel workqueue based btrfs_workqueue

[Qu Wenruo]

Add a new btrfs_workqueue_struct which use kernel workqueue to implement
most of the original btrfs_workers, to replace btrfs_workers.

With this patchset, redundant workqueue codes are replaced with kernel
workqueue infrastructure, which not only reduces the code size but also the
effort to maintain it.

The result(somewhat outdated though) from sysbench shows minor improvement on the following server:
CPU: two-way Xeon X5660
RAM: 4G 
HDD: SAS HDD, 150G total, 100G partition for btrfs test

Test result on default mount option:
https://docs.google.com/spreadsheet/ccc?key=0AhpkL3ehzX3pdENjajJTWFg5d1BWbExnYWFpMTJxeUE&usp=sharing

Test result on "-o compress" mount option:
https://docs.google.com/spreadsheet/ccc?key=0AhpkL3ehzX3pdHdTTEJ6OW96SXJFaDR5enB1SzMzc0E&usp=sharing

Changelog:
v1->v2:
  - Fix some workqueue flags.
v2->v3:
  - Add the thresholding mechanism to simulate the old behavior
  - Convert all the btrfs_workers to btrfs_workrqueue_struct.
  - Fix some potential deadlock when executed in IRQ handler.
v3->v4:
  - Change the ordered workqueue implement to fix the performance drop in 32K
    multi thread random write.
  - Change the high priority workqueue implement to get an independent high
    workqueue without starving problem.
  - Simplify the btrfs_alloc_workqueue parameters.
  - Coding style cleanup.
  - Remove the redundant "_struct" suffix.
v4->v5:
  - Fix a multithread free-and-use bug reported by Josef and David.

Qu Wenruo (18):
  btrfs: Cleanup the unused struct async_sched.
  btrfs: Added btrfs_workqueue_struct implemented ordered execution
    based on kernel workqueue
  btrfs: Add high priority workqueue support for btrfs_workqueue_struct
  btrfs: Add threshold workqueue based on kernel workqueue
  btrfs: Replace fs_info->workers with btrfs_workqueue.
  btrfs: Replace fs_info->delalloc_workers with btrfs_workqueue
  btrfs: Replace fs_info->submit_workers with btrfs_workqueue.
  btrfs: Replace fs_info->flush_workers with btrfs_workqueue.
  btrfs: Replace fs_info->endio_* workqueue with btrfs_workqueue.
  btrfs: Replace fs_info->rmw_workers workqueue with btrfs_workqueue.
  btrfs: Replace fs_info->cache_workers workqueue with btrfs_workqueue.
  btrfs: Replace fs_info->readahead_workers workqueue with
    btrfs_workqueue.
  btrfs: Replace fs_info->fixup_workers workqueue with btrfs_workqueue.
  btrfs: Replace fs_info->delayed_workers workqueue with
    btrfs_workqueue.
  btrfs: Replace fs_info->qgroup_rescan_worker workqueue with
    btrfs_workqueue.
  btrfs: Replace fs_info->scrub_* workqueue with btrfs_workqueue.
  btrfs: Cleanup the old btrfs_worker.
  btrfs: Cleanup the "_struct" suffix in btrfs_workequeue

 fs/btrfs/async-thread.c  | 830 ++++++++++++-----------------------------------
 fs/btrfs/async-thread.h  | 119 ++-----
 fs/btrfs/ctree.h         |  39 ++-
 fs/btrfs/delayed-inode.c |   6 +-
 fs/btrfs/disk-io.c       | 212 +++++-------
 fs/btrfs/extent-tree.c   |   4 +-
 fs/btrfs/inode.c         |  38 +--
 fs/btrfs/ordered-data.c  |  11 +-
 fs/btrfs/qgroup.c        |  15 +-
 fs/btrfs/raid56.c        |  21 +-
 fs/btrfs/reada.c         |   4 +-
 fs/btrfs/scrub.c         |  70 ++--
 fs/btrfs/super.c         |  36 +-
 fs/btrfs/volumes.c       |  16 +-
 14 files changed, 446 insertions(+), 975 deletions(-)

-- 
1.9.0

[PATCH v5 01/18] btrfs: Cleanup the unused struct async_sched.

[Qu Wenruo]

The struct async_sched is not used by any codes and can be removed.

Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Reviewed-by: Josef Bacik <jbacik@fusionio.com>
Tested-by: David Sterba <dsterba@suse.cz>
---
Changelog:
v1->v2:
  None.
v2->v3:
  None.
v3->v4:
  None:
v4->v5:
  None
---
 fs/btrfs/volumes.c | 7 -------
 1 file changed, 7 deletions(-)

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 07629e9..82a63b1 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -5323,13 +5323,6 @@ static void btrfs_end_bio(struct bio *bio, int err)
 	}
 }
 
-struct async_sched {
-	struct bio *bio;
-	int rw;
-	struct btrfs_fs_info *info;
-	struct btrfs_work work;
-};
-
 /*
  * see run_scheduled_bios for a description of why bios are collected for
  * async submit.
-- 
1.9.0

[PATCH v5 02/18] btrfs: Added btrfs_workqueue_struct implemented ordered execution based on kernel workqueue

[Qu Wenruo]

Use kernel workqueue to implement a new btrfs_workqueue_struct, which
has the ordering execution feature like the btrfs_worker.

The func is executed in a concurrency way, and the
ordred_func/ordered_free is executed in the sequence them are queued
after the corresponding func is done.

The new btrfs_workqueue works much like the original one, one workqueue
for normal work and a list for ordered work.
When a work is queued, ordered work will be added to the list and helper
function will be queued into the workqueue.
The helper function will execute a normal work and then check and execute as many
ordered work as possible in the sequence they were queued.

At this patch, high priority work queue or thresholding is not added yet.
The high priority feature and thresholding will be added in the following patches.

Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Tested-by: David Sterba <dsterba@suse.cz>
---
Changelog:
v1->v2:
  None.
v2->v3:
  - Fix the potential deadlock discovered by kernel lockdep.
  - Reuse the async-thread.[ch] files.
  - Make the ordered_func optional, which makes it adaptable to
    all btrfs_workers.
v3->v4:
  - Use the old list method to implement ordered workqueue.
    Previous 3 wq implement needs extra time waiting for scheduling,
    which caused up to 40% performance drop in compress tests.
    The old list method(after executing a normal work, check the order_list
    and executing) does not need the extra scheduling things.
  - Simplify the btrfs_alloc_workqueue parameters.
    Now only one name is needed, and ordered work mechanism is determined using
    work->ordered_func.
  - Fix memory leak in btrfs_destroy_workqueue.
v4->v5:
  - Fix a multithread free-and-use bug reported by Josef and David.
---
 fs/btrfs/async-thread.c | 137 ++++++++++++++++++++++++++++++++++++++++++++++++
 fs/btrfs/async-thread.h |  27 ++++++++++
 2 files changed, 164 insertions(+)

diff --git a/fs/btrfs/async-thread.c b/fs/btrfs/async-thread.c
index 0b78bf2..905de02 100644
--- a/fs/btrfs/async-thread.c
+++ b/fs/btrfs/async-thread.c
@@ -1,5 +1,6 @@
 /*
  * Copyright (C) 2007 Oracle.  All rights reserved.
+ * Copyright (C) 2014 Fujitsu.  All rights reserved.
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public
@@ -21,6 +22,7 @@
 #include <linux/list.h>
 #include <linux/spinlock.h>
 #include <linux/freezer.h>
+#include <linux/workqueue.h>
 #include "async-thread.h"
 
 #define WORK_QUEUED_BIT 0
@@ -727,3 +729,138 @@ void btrfs_queue_worker(struct btrfs_workers *workers, struct btrfs_work *work)
 		wake_up_process(worker->task);
 	spin_unlock_irqrestore(&worker->lock, flags);
 }
+
+struct btrfs_workqueue_struct {
+	struct workqueue_struct *normal_wq;
+	/* List head pointing to ordered work list */
+	struct list_head ordered_list;
+
+	/* Spinlock for ordered_list */
+	spinlock_t list_lock;
+};
+
+struct btrfs_workqueue_struct *btrfs_alloc_workqueue(char *name,
+						     int flags,
+						     int max_active)
+{
+	struct btrfs_workqueue_struct *ret = kzalloc(sizeof(*ret), GFP_NOFS);
+
+	if (unlikely(!ret))
+		return NULL;
+
+	ret->normal_wq = alloc_workqueue("%s-%s", flags, max_active,
+					 "btrfs", name);
+	if (unlikely(!ret->normal_wq)) {
+		kfree(ret);
+		return NULL;
+	}
+
+	INIT_LIST_HEAD(&ret->ordered_list);
+	spin_lock_init(&ret->list_lock);
+	return ret;
+}
+
+static void run_ordered_work(struct btrfs_workqueue_struct *wq)
+{
+	struct list_head *list = &wq->ordered_list;
+	struct btrfs_work_struct *work;
+	spinlock_t *lock = &wq->list_lock;
+	unsigned long flags;
+
+	while (1) {
+		spin_lock_irqsave(lock, flags);
+		if (list_empty(list))
+			break;
+		work = list_entry(list->next, struct btrfs_work_struct,
+				  ordered_list);
+		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_irqrestore(lock, flags);
+		work->ordered_func(work);
+
+		/* now take the lock again and drop our item from the list */
+		spin_lock_irqsave(lock, flags);
+		list_del(&work->ordered_list);
+		spin_unlock_irqrestore(lock, flags);
+
+		/*
+		 * we don't want to call the ordered free functions
+		 * with the lock held though
+		 */
+		work->ordered_free(work);
+	}
+	spin_unlock_irqrestore(lock, flags);
+}
+
+static void normal_work_helper(struct work_struct *arg)
+{
+	struct btrfs_work_struct *work;
+	struct btrfs_workqueue_struct *wq;
+	int need_order = 0;
+
+	work = container_of(arg, struct btrfs_work_struct, normal_work);
+	/*
+	 * We should not touch things inside work in the following cases:
+	 * 1) after work->func() if it has no ordered_free
+	 *    Since the struct is freed in work->func().
+	 * 2) after setting WORK_DONE_BIT
+	 *    The work may be freed in other threads almost instantly.
+	 * So we save the needed things here.
+	 */
+	if (work->ordered_func)
+		need_order = 1;
+	wq = work->wq;
+
+	work->func(work);
+	if (need_order) {
+		set_bit(WORK_DONE_BIT, &work->flags);
+		run_ordered_work(wq);
+	}
+}
+
+void btrfs_init_work(struct btrfs_work_struct *work,
+		     void (*func)(struct btrfs_work_struct *),
+		     void (*ordered_func)(struct btrfs_work_struct *),
+		     void (*ordered_free)(struct btrfs_work_struct *))
+{
+	work->func = func;
+	work->ordered_func = ordered_func;
+	work->ordered_free = ordered_free;
+	INIT_WORK(&work->normal_work, normal_work_helper);
+	INIT_LIST_HEAD(&work->ordered_list);
+	work->flags = 0;
+}
+
+void btrfs_queue_work(struct btrfs_workqueue_struct *wq,
+		      struct btrfs_work_struct *work)
+{
+	unsigned long flags;
+
+	work->wq = wq;
+	if (work->ordered_func) {
+		spin_lock_irqsave(&wq->list_lock, flags);
+		list_add_tail(&work->ordered_list, &wq->ordered_list);
+		spin_unlock_irqrestore(&wq->list_lock, flags);
+	}
+	queue_work(wq->normal_wq, &work->normal_work);
+}
+
+void btrfs_destroy_workqueue(struct btrfs_workqueue_struct *wq)
+{
+	destroy_workqueue(wq->normal_wq);
+	kfree(wq);
+}
+
+void btrfs_workqueue_set_max(struct btrfs_workqueue_struct *wq, int max)
+{
+	workqueue_set_max_active(wq->normal_wq, max);
+}
diff --git a/fs/btrfs/async-thread.h b/fs/btrfs/async-thread.h
index 1f26792..9d8da53 100644
--- a/fs/btrfs/async-thread.h
+++ b/fs/btrfs/async-thread.h
@@ -1,5 +1,6 @@
 /*
  * Copyright (C) 2007 Oracle.  All rights reserved.
+ * Copyright (C) 2014 Fujitsu.  All rights reserved.
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public
@@ -118,4 +119,30 @@ 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);
+
+struct btrfs_workqueue_struct;
+
+struct btrfs_work_struct {
+	void (*func)(struct btrfs_work_struct *arg);
+	void (*ordered_func)(struct btrfs_work_struct *arg);
+	void (*ordered_free)(struct btrfs_work_struct *arg);
+
+	/* Don't touch things below */
+	struct work_struct normal_work;
+	struct list_head ordered_list;
+	struct btrfs_workqueue_struct *wq;
+	unsigned long flags;
+};
+
+struct btrfs_workqueue_struct *btrfs_alloc_workqueue(char *name,
+						     int flags,
+						     int max_active);
+void btrfs_init_work(struct btrfs_work_struct *work,
+		     void (*func)(struct btrfs_work_struct *),
+		     void (*ordered_func)(struct btrfs_work_struct *),
+		     void (*ordered_free)(struct btrfs_work_struct *));
+void btrfs_queue_work(struct btrfs_workqueue_struct *wq,
+		      struct btrfs_work_struct *work);
+void btrfs_destroy_workqueue(struct btrfs_workqueue_struct *wq);
+void btrfs_workqueue_set_max(struct btrfs_workqueue_struct *wq, int max);
 #endif
-- 
1.9.0

[PATCH v5 03/18] btrfs: Add high priority workqueue support for btrfs_workqueue_struct

[Qu Wenruo]

Add high priority function to btrfs_workqueue.

This is implemented by embedding a btrfs_workqueue into a
btrfs_workqueue and use some helper functions to differ the normal
priority wq and high priority wq.
So the high priority wq is completely independent from the normal
workqueue.

Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Tested-by: David Sterba <dsterba@suse.cz>
---
Changelog:
v1->v2:
  None
v2->v3:
  None
v3->v4:
  - Implement high priority workqueue independently.
    Now high priority wq is implemented as a normal btrfs_workqueue,
    with independent ordering/thresholding mechanism.
    This fixed the problem that high priority wq and normal wq shared one
    ordered wq.
v4->v5:
  None
---
 fs/btrfs/async-thread.c | 91 ++++++++++++++++++++++++++++++++++++++++++-------
 fs/btrfs/async-thread.h |  5 ++-
 2 files changed, 83 insertions(+), 13 deletions(-)

diff --git a/fs/btrfs/async-thread.c b/fs/btrfs/async-thread.c
index 905de02..193c849 100644
--- a/fs/btrfs/async-thread.c
+++ b/fs/btrfs/async-thread.c
@@ -730,7 +730,7 @@ void btrfs_queue_worker(struct btrfs_workers *workers, struct btrfs_work *work)
 	spin_unlock_irqrestore(&worker->lock, flags);
 }
 
-struct btrfs_workqueue_struct {
+struct __btrfs_workqueue_struct {
 	struct workqueue_struct *normal_wq;
 	/* List head pointing to ordered work list */
 	struct list_head ordered_list;
@@ -739,6 +739,38 @@ struct btrfs_workqueue_struct {
 	spinlock_t list_lock;
 };
 
+struct btrfs_workqueue_struct {
+	struct __btrfs_workqueue_struct *normal;
+	struct __btrfs_workqueue_struct *high;
+};
+
+static inline struct __btrfs_workqueue_struct
+*__btrfs_alloc_workqueue(char *name, int flags, int max_active)
+{
+	struct __btrfs_workqueue_struct *ret = kzalloc(sizeof(*ret), GFP_NOFS);
+
+	if (unlikely(!ret))
+		return NULL;
+
+	if (flags & WQ_HIGHPRI)
+		ret->normal_wq = alloc_workqueue("%s-%s-high", flags,
+						 max_active, "btrfs", name);
+	else
+		ret->normal_wq = alloc_workqueue("%s-%s", flags,
+						 max_active, "btrfs", name);
+	if (unlikely(!ret->normal_wq)) {
+		kfree(ret);
+		return NULL;
+	}
+
+	INIT_LIST_HEAD(&ret->ordered_list);
+	spin_lock_init(&ret->list_lock);
+	return ret;
+}
+
+static inline void
+__btrfs_destroy_workqueue(struct __btrfs_workqueue_struct *wq);
+
 struct btrfs_workqueue_struct *btrfs_alloc_workqueue(char *name,
 						     int flags,
 						     int max_active)
@@ -748,19 +780,25 @@ struct btrfs_workqueue_struct *btrfs_alloc_workqueue(char *name,
 	if (unlikely(!ret))
 		return NULL;
 
-	ret->normal_wq = alloc_workqueue("%s-%s", flags, max_active,
-					 "btrfs", name);
-	if (unlikely(!ret->normal_wq)) {
+	ret->normal = __btrfs_alloc_workqueue(name, flags & ~WQ_HIGHPRI,
+					      max_active);
+	if (unlikely(!ret->normal)) {
 		kfree(ret);
 		return NULL;
 	}
 
-	INIT_LIST_HEAD(&ret->ordered_list);
-	spin_lock_init(&ret->list_lock);
+	if (flags & WQ_HIGHPRI) {
+		ret->high = __btrfs_alloc_workqueue(name, flags, max_active);
+		if (unlikely(!ret->high)) {
+			__btrfs_destroy_workqueue(ret->normal);
+			kfree(ret);
+			return NULL;
+		}
+	}
 	return ret;
 }
 
-static void run_ordered_work(struct btrfs_workqueue_struct *wq)
+static void run_ordered_work(struct __btrfs_workqueue_struct *wq)
 {
 	struct list_head *list = &wq->ordered_list;
 	struct btrfs_work_struct *work;
@@ -804,7 +842,7 @@ static void run_ordered_work(struct btrfs_workqueue_struct *wq)
 static void normal_work_helper(struct work_struct *arg)
 {
 	struct btrfs_work_struct *work;
-	struct btrfs_workqueue_struct *wq;
+	struct __btrfs_workqueue_struct *wq;
 	int need_order = 0;
 
 	work = container_of(arg, struct btrfs_work_struct, normal_work);
@@ -840,8 +878,8 @@ void btrfs_init_work(struct btrfs_work_struct *work,
 	work->flags = 0;
 }
 
-void btrfs_queue_work(struct btrfs_workqueue_struct *wq,
-		      struct btrfs_work_struct *work)
+static inline void __btrfs_queue_work(struct __btrfs_workqueue_struct *wq,
+				      struct btrfs_work_struct *work)
 {
 	unsigned long flags;
 
@@ -854,13 +892,42 @@ void btrfs_queue_work(struct btrfs_workqueue_struct *wq,
 	queue_work(wq->normal_wq, &work->normal_work);
 }
 
-void btrfs_destroy_workqueue(struct btrfs_workqueue_struct *wq)
+void btrfs_queue_work(struct btrfs_workqueue_struct *wq,
+		      struct btrfs_work_struct *work)
+{
+	struct __btrfs_workqueue_struct *dest_wq;
+
+	if (test_bit(WORK_HIGH_PRIO_BIT, &work->flags) && wq->high)
+		dest_wq = wq->high;
+	else
+		dest_wq = wq->normal;
+	__btrfs_queue_work(dest_wq, work);
+}
+
+static inline void
+__btrfs_destroy_workqueue(struct __btrfs_workqueue_struct *wq)
 {
 	destroy_workqueue(wq->normal_wq);
 	kfree(wq);
 }
 
+void btrfs_destroy_workqueue(struct btrfs_workqueue_struct *wq)
+{
+	if (!wq)
+		return;
+	if (wq->high)
+		__btrfs_destroy_workqueue(wq->high);
+	__btrfs_destroy_workqueue(wq->normal);
+}
+
 void btrfs_workqueue_set_max(struct btrfs_workqueue_struct *wq, int max)
 {
-	workqueue_set_max_active(wq->normal_wq, max);
+	workqueue_set_max_active(wq->normal->normal_wq, max);
+	if (wq->high)
+		workqueue_set_max_active(wq->high->normal_wq, max);
+}
+
+void btrfs_set_work_high_priority(struct btrfs_work_struct *work)
+{
+	set_bit(WORK_HIGH_PRIO_BIT, &work->flags);
 }
diff --git a/fs/btrfs/async-thread.h b/fs/btrfs/async-thread.h
index 9d8da53..fce623c 100644
--- a/fs/btrfs/async-thread.h
+++ b/fs/btrfs/async-thread.h
@@ -121,6 +121,8 @@ void btrfs_requeue_work(struct btrfs_work *work);
 void btrfs_set_work_high_prio(struct btrfs_work *work);
 
 struct btrfs_workqueue_struct;
+/* Internal use only */
+struct __btrfs_workqueue_struct;
 
 struct btrfs_work_struct {
 	void (*func)(struct btrfs_work_struct *arg);
@@ -130,7 +132,7 @@ struct btrfs_work_struct {
 	/* Don't touch things below */
 	struct work_struct normal_work;
 	struct list_head ordered_list;
-	struct btrfs_workqueue_struct *wq;
+	struct __btrfs_workqueue_struct *wq;
 	unsigned long flags;
 };
 
@@ -145,4 +147,5 @@ void btrfs_queue_work(struct btrfs_workqueue_struct *wq,
 		      struct btrfs_work_struct *work);
 void btrfs_destroy_workqueue(struct btrfs_workqueue_struct *wq);
 void btrfs_workqueue_set_max(struct btrfs_workqueue_struct *wq, int max);
+void btrfs_set_work_high_priority(struct btrfs_work_struct *work);
 #endif
-- 
1.9.0

[PATCH v5 04/18] btrfs: Add threshold workqueue based on kernel workqueue

[Qu Wenruo]

The original btrfs_workers has thresholding functions to dynamically
create or destroy kthreads.

Though there is no such function in kernel workqueue because the worker
is not created manually, we can still use the workqueue_set_max_active
to simulated the behavior, mainly to achieve a better HDD performance by
setting a high threshold on submit_workers.
(Sadly, no resource can be saved)

So in this patch, extra workqueue pending counters are introduced to
dynamically change the max active of each btrfs_workqueue_struct, hoping
to restore the behavior of the original thresholding function.

Also, workqueue_set_max_active use a mutex to protect workqueue_struct,
which is not meant to be called too frequently, so a new interval
mechanism is applied, that will only call workqueue_set_max_active after
a count of work is queued. Hoping to balance both the random and
sequence performance on HDD.

Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Tested-by: David Sterba <dsterba@suse.cz>
---
Changelog:
v2->v3:
  - Add thresholding mechanism to simulate the old thresholding mechanism.
  - Will not enable thresholding when thresh is set to small value.
v3->v4:
  None
v4->v5:
  None
---
 fs/btrfs/async-thread.c | 107 ++++++++++++++++++++++++++++++++++++++++++++----
 fs/btrfs/async-thread.h |   3 +-
 2 files changed, 101 insertions(+), 9 deletions(-)

diff --git a/fs/btrfs/async-thread.c b/fs/btrfs/async-thread.c
index 193c849..977bce2 100644
--- a/fs/btrfs/async-thread.c
+++ b/fs/btrfs/async-thread.c
@@ -30,6 +30,9 @@
 #define WORK_ORDER_DONE_BIT 2
 #define WORK_HIGH_PRIO_BIT 3
 
+#define NO_THRESHOLD (-1)
+#define DFT_THRESHOLD (32)
+
 /*
  * container for the kthread task pointer and the list of pending work
  * One of these is allocated per thread.
@@ -737,6 +740,14 @@ struct __btrfs_workqueue_struct {
 
 	/* Spinlock for ordered_list */
 	spinlock_t list_lock;
+
+	/* Thresholding related variants */
+	atomic_t pending;
+	int max_active;
+	int current_max;
+	int thresh;
+	unsigned int count;
+	spinlock_t thres_lock;
 };
 
 struct btrfs_workqueue_struct {
@@ -745,19 +756,34 @@ struct btrfs_workqueue_struct {
 };
 
 static inline struct __btrfs_workqueue_struct
-*__btrfs_alloc_workqueue(char *name, int flags, int max_active)
+*__btrfs_alloc_workqueue(char *name, int flags, int max_active, int thresh)
 {
 	struct __btrfs_workqueue_struct *ret = kzalloc(sizeof(*ret), GFP_NOFS);
 
 	if (unlikely(!ret))
 		return NULL;
 
+	ret->max_active = max_active;
+	atomic_set(&ret->pending, 0);
+	if (thresh == 0)
+		thresh = DFT_THRESHOLD;
+	/* For low threshold, disabling threshold is a better choice */
+	if (thresh < DFT_THRESHOLD) {
+		ret->current_max = max_active;
+		ret->thresh = NO_THRESHOLD;
+	} else {
+		ret->current_max = 1;
+		ret->thresh = thresh;
+	}
+
 	if (flags & WQ_HIGHPRI)
 		ret->normal_wq = alloc_workqueue("%s-%s-high", flags,
-						 max_active, "btrfs", name);
+						 ret->max_active,
+						 "btrfs", name);
 	else
 		ret->normal_wq = alloc_workqueue("%s-%s", flags,
-						 max_active, "btrfs", name);
+						 ret->max_active, "btrfs",
+						 name);
 	if (unlikely(!ret->normal_wq)) {
 		kfree(ret);
 		return NULL;
@@ -765,6 +791,7 @@ static inline struct __btrfs_workqueue_struct
 
 	INIT_LIST_HEAD(&ret->ordered_list);
 	spin_lock_init(&ret->list_lock);
+	spin_lock_init(&ret->thres_lock);
 	return ret;
 }
 
@@ -773,7 +800,8 @@ __btrfs_destroy_workqueue(struct __btrfs_workqueue_struct *wq);
 
 struct btrfs_workqueue_struct *btrfs_alloc_workqueue(char *name,
 						     int flags,
-						     int max_active)
+						     int max_active,
+						     int thresh)
 {
 	struct btrfs_workqueue_struct *ret = kzalloc(sizeof(*ret), GFP_NOFS);
 
@@ -781,14 +809,15 @@ struct btrfs_workqueue_struct *btrfs_alloc_workqueue(char *name,
 		return NULL;
 
 	ret->normal = __btrfs_alloc_workqueue(name, flags & ~WQ_HIGHPRI,
-					      max_active);
+					      max_active, thresh);
 	if (unlikely(!ret->normal)) {
 		kfree(ret);
 		return NULL;
 	}
 
 	if (flags & WQ_HIGHPRI) {
-		ret->high = __btrfs_alloc_workqueue(name, flags, max_active);
+		ret->high = __btrfs_alloc_workqueue(name, flags, max_active,
+						    thresh);
 		if (unlikely(!ret->high)) {
 			__btrfs_destroy_workqueue(ret->normal);
 			kfree(ret);
@@ -798,6 +827,66 @@ struct btrfs_workqueue_struct *btrfs_alloc_workqueue(char *name,
 	return ret;
 }
 
+/*
+ * Hook for threshold which will be called in btrfs_queue_work.
+ * This hook WILL be called in IRQ handler context,
+ * so workqueue_set_max_active MUST NOT be called in this hook
+ */
+static inline void thresh_queue_hook(struct __btrfs_workqueue_struct *wq)
+{
+	if (wq->thresh == NO_THRESHOLD)
+		return;
+	atomic_inc(&wq->pending);
+}
+
+/*
+ * Hook for threshold which will be called before executing the work,
+ * This hook is called in kthread content.
+ * So workqueue_set_max_active is called here.
+ */
+static inline void thresh_exec_hook(struct __btrfs_workqueue_struct *wq)
+{
+	int new_max_active;
+	long pending;
+	int need_change = 0;
+
+	if (wq->thresh == NO_THRESHOLD)
+		return;
+
+	atomic_dec(&wq->pending);
+	spin_lock(&wq->thres_lock);
+	/*
+	 * Use wq->count to limit the calling frequency of
+	 * workqueue_set_max_active.
+	 */
+	wq->count++;
+	wq->count %= (wq->thresh / 4);
+	if (!wq->count)
+		goto  out;
+	new_max_active = wq->current_max;
+
+	/*
+	 * pending may be changed later, but it's OK since we really
+	 * don't need it so accurate to calculate new_max_active.
+	 */
+	pending = atomic_read(&wq->pending);
+	if (pending > wq->thresh)
+		new_max_active++;
+	if (pending < wq->thresh / 2)
+		new_max_active--;
+	new_max_active = clamp_val(new_max_active, 1, wq->max_active);
+	if (new_max_active != wq->current_max)  {
+		need_change = 1;
+		wq->current_max = new_max_active;
+	}
+out:
+	spin_unlock(&wq->thres_lock);
+
+	if (need_change) {
+		workqueue_set_max_active(wq->normal_wq, wq->current_max);
+	}
+}
+
 static void run_ordered_work(struct __btrfs_workqueue_struct *wq)
 {
 	struct list_head *list = &wq->ordered_list;
@@ -858,6 +947,7 @@ static void normal_work_helper(struct work_struct *arg)
 		need_order = 1;
 	wq = work->wq;
 
+	thresh_exec_hook(wq);
 	work->func(work);
 	if (need_order) {
 		set_bit(WORK_DONE_BIT, &work->flags);
@@ -884,6 +974,7 @@ static inline void __btrfs_queue_work(struct __btrfs_workqueue_struct *wq,
 	unsigned long flags;
 
 	work->wq = wq;
+	thresh_queue_hook(wq);
 	if (work->ordered_func) {
 		spin_lock_irqsave(&wq->list_lock, flags);
 		list_add_tail(&work->ordered_list, &wq->ordered_list);
@@ -922,9 +1013,9 @@ void btrfs_destroy_workqueue(struct btrfs_workqueue_struct *wq)
 
 void btrfs_workqueue_set_max(struct btrfs_workqueue_struct *wq, int max)
 {
-	workqueue_set_max_active(wq->normal->normal_wq, max);
+	wq->normal->max_active = max;
 	if (wq->high)
-		workqueue_set_max_active(wq->high->normal_wq, max);
+		wq->high->max_active = max;
 }
 
 void btrfs_set_work_high_priority(struct btrfs_work_struct *work)
diff --git a/fs/btrfs/async-thread.h b/fs/btrfs/async-thread.h
index fce623c..3129d8a 100644
--- a/fs/btrfs/async-thread.h
+++ b/fs/btrfs/async-thread.h
@@ -138,7 +138,8 @@ struct btrfs_work_struct {
 
 struct btrfs_workqueue_struct *btrfs_alloc_workqueue(char *name,
 						     int flags,
-						     int max_active);
+						     int max_active,
+						     int thresh);
 void btrfs_init_work(struct btrfs_work_struct *work,
 		     void (*func)(struct btrfs_work_struct *),
 		     void (*ordered_func)(struct btrfs_work_struct *),
-- 
1.9.0

[PATCH v5 05/18] btrfs: Replace fs_info->workers with btrfs_workqueue.

[Qu Wenruo]

Use the newly created btrfs_workqueue_struct to replace the original
fs_info->workers

Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Tested-by: David Sterba <dsterba@suse.cz>
---
Changelog:
v1->v2:
  None
v2->v3:
  None
v3->v4:
  - Use the simplified btrfs_alloc_workqueue API.
v4->v5:
  None
---
 fs/btrfs/ctree.h   |  2 +-
 fs/btrfs/disk-io.c | 41 +++++++++++++++++++++--------------------
 fs/btrfs/super.c   |  2 +-
 3 files changed, 23 insertions(+), 22 deletions(-)

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index dac6653..448df5e 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1505,7 +1505,7 @@ struct btrfs_fs_info {
 	 * two
 	 */
 	struct btrfs_workers generic_worker;
-	struct btrfs_workers workers;
+	struct btrfs_workqueue_struct *workers;
 	struct btrfs_workers delalloc_workers;
 	struct btrfs_workers flush_workers;
 	struct btrfs_workers endio_workers;
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index cc1b423..4040a43 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -108,7 +108,7 @@ struct async_submit_bio {
 	 * can't tell us where in the file the bio should go
 	 */
 	u64 bio_offset;
-	struct btrfs_work work;
+	struct btrfs_work_struct work;
 	int error;
 };
 
@@ -738,12 +738,12 @@ int btrfs_bio_wq_end_io(struct btrfs_fs_info *info, struct bio *bio,
 unsigned long btrfs_async_submit_limit(struct btrfs_fs_info *info)
 {
 	unsigned long limit = min_t(unsigned long,
-				    info->workers.max_workers,
+				    info->thread_pool_size,
 				    info->fs_devices->open_devices);
 	return 256 * limit;
 }
 
-static void run_one_async_start(struct btrfs_work *work)
+static void run_one_async_start(struct btrfs_work_struct *work)
 {
 	struct async_submit_bio *async;
 	int ret;
@@ -756,7 +756,7 @@ static void run_one_async_start(struct btrfs_work *work)
 		async->error = ret;
 }
 
-static void run_one_async_done(struct btrfs_work *work)
+static void run_one_async_done(struct btrfs_work_struct *work)
 {
 	struct btrfs_fs_info *fs_info;
 	struct async_submit_bio *async;
@@ -783,7 +783,7 @@ static void run_one_async_done(struct btrfs_work *work)
 			       async->bio_offset);
 }
 
-static void run_one_async_free(struct btrfs_work *work)
+static void run_one_async_free(struct btrfs_work_struct *work)
 {
 	struct async_submit_bio *async;
 
@@ -811,11 +811,9 @@ int btrfs_wq_submit_bio(struct btrfs_fs_info *fs_info, struct inode *inode,
 	async->submit_bio_start = submit_bio_start;
 	async->submit_bio_done = submit_bio_done;
 
-	async->work.func = run_one_async_start;
-	async->work.ordered_func = run_one_async_done;
-	async->work.ordered_free = run_one_async_free;
+	btrfs_init_work(&async->work, run_one_async_start,
+			run_one_async_done, run_one_async_free);
 
-	async->work.flags = 0;
 	async->bio_flags = bio_flags;
 	async->bio_offset = bio_offset;
 
@@ -824,9 +822,9 @@ int btrfs_wq_submit_bio(struct btrfs_fs_info *fs_info, struct inode *inode,
 	atomic_inc(&fs_info->nr_async_submits);
 
 	if (rw & REQ_SYNC)
-		btrfs_set_work_high_prio(&async->work);
+		btrfs_set_work_high_priority(&async->work);
 
-	btrfs_queue_worker(&fs_info->workers, &async->work);
+	btrfs_queue_work(fs_info->workers, &async->work);
 
 	while (atomic_read(&fs_info->async_submit_draining) &&
 	      atomic_read(&fs_info->nr_async_submits)) {
@@ -1996,7 +1994,7 @@ static void btrfs_stop_all_workers(struct btrfs_fs_info *fs_info)
 	btrfs_stop_workers(&fs_info->generic_worker);
 	btrfs_stop_workers(&fs_info->fixup_workers);
 	btrfs_stop_workers(&fs_info->delalloc_workers);
-	btrfs_stop_workers(&fs_info->workers);
+	btrfs_destroy_workqueue(fs_info->workers);
 	btrfs_stop_workers(&fs_info->endio_workers);
 	btrfs_stop_workers(&fs_info->endio_meta_workers);
 	btrfs_stop_workers(&fs_info->endio_raid56_workers);
@@ -2100,6 +2098,8 @@ int open_ctree(struct super_block *sb,
 	int err = -EINVAL;
 	int num_backups_tried = 0;
 	int backup_index = 0;
+	int max_active;
+	int flags = WQ_MEM_RECLAIM | WQ_FREEZABLE | WQ_UNBOUND;
 	bool create_uuid_tree;
 	bool check_uuid_tree;
 
@@ -2468,12 +2468,13 @@ int open_ctree(struct super_block *sb,
 		goto fail_alloc;
 	}
 
+	max_active = fs_info->thread_pool_size;
 	btrfs_init_workers(&fs_info->generic_worker,
 			   "genwork", 1, NULL);
 
-	btrfs_init_workers(&fs_info->workers, "worker",
-			   fs_info->thread_pool_size,
-			   &fs_info->generic_worker);
+	fs_info->workers =
+		btrfs_alloc_workqueue("worker", flags | WQ_HIGHPRI,
+				      max_active, 16);
 
 	btrfs_init_workers(&fs_info->delalloc_workers, "delalloc",
 			   fs_info->thread_pool_size, NULL);
@@ -2494,9 +2495,6 @@ int open_ctree(struct super_block *sb,
 	 */
 	fs_info->submit_workers.idle_thresh = 64;
 
-	fs_info->workers.idle_thresh = 16;
-	fs_info->workers.ordered = 1;
-
 	fs_info->delalloc_workers.idle_thresh = 2;
 	fs_info->delalloc_workers.ordered = 1;
 
@@ -2548,8 +2546,7 @@ 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->workers);
-	ret |= btrfs_start_workers(&fs_info->generic_worker);
+	ret = btrfs_start_workers(&fs_info->generic_worker);
 	ret |= btrfs_start_workers(&fs_info->submit_workers);
 	ret |= btrfs_start_workers(&fs_info->delalloc_workers);
 	ret |= btrfs_start_workers(&fs_info->fixup_workers);
@@ -2569,6 +2566,10 @@ int open_ctree(struct super_block *sb,
 		err = -ENOMEM;
 		goto fail_sb_buffer;
 	}
+	if (!(fs_info->workers)) {
+		err = -ENOMEM;
+		goto fail_sb_buffer;
+	}
 
 	fs_info->bdi.ra_pages *= btrfs_super_num_devices(disk_super);
 	fs_info->bdi.ra_pages = max(fs_info->bdi.ra_pages,
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 97cc241..7039d3d7 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -1317,7 +1317,7 @@ static void btrfs_resize_thread_pool(struct btrfs_fs_info *fs_info,
 	       old_pool_size, new_pool_size);
 
 	btrfs_set_max_workers(&fs_info->generic_worker, new_pool_size);
-	btrfs_set_max_workers(&fs_info->workers, new_pool_size);
+	btrfs_workqueue_set_max(fs_info->workers, new_pool_size);
 	btrfs_set_max_workers(&fs_info->delalloc_workers, new_pool_size);
 	btrfs_set_max_workers(&fs_info->submit_workers, new_pool_size);
 	btrfs_set_max_workers(&fs_info->caching_workers, new_pool_size);
-- 
1.9.0

[PATCH v5 06/18] btrfs: Replace fs_info->delalloc_workers with btrfs_workqueue

[Qu Wenruo]

Much like the fs_info->workers, replace the fs_info->delalloc_workers
use the same btrfs_workqueue.

Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Tested-by: David Sterba <dsterba@suse.cz>
---
Changelog:
v1->v2:
  None
v2->v3:
  None
v3->v4:
  - Use the simplified btrfs_alloc_workqueue API.
v4->v5:
  None
---
 fs/btrfs/ctree.h   |  2 +-
 fs/btrfs/disk-io.c | 12 ++++--------
 fs/btrfs/inode.c   | 18 ++++++++----------
 fs/btrfs/super.c   |  2 +-
 4 files changed, 14 insertions(+), 20 deletions(-)

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 448df5e..4e11f4b 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1506,7 +1506,7 @@ struct btrfs_fs_info {
 	 */
 	struct btrfs_workers generic_worker;
 	struct btrfs_workqueue_struct *workers;
-	struct btrfs_workers delalloc_workers;
+	struct btrfs_workqueue_struct *delalloc_workers;
 	struct btrfs_workers flush_workers;
 	struct btrfs_workers endio_workers;
 	struct btrfs_workers endio_meta_workers;
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 4040a43..f97bd17 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1993,7 +1993,7 @@ static void btrfs_stop_all_workers(struct btrfs_fs_info *fs_info)
 {
 	btrfs_stop_workers(&fs_info->generic_worker);
 	btrfs_stop_workers(&fs_info->fixup_workers);
-	btrfs_stop_workers(&fs_info->delalloc_workers);
+	btrfs_destroy_workqueue(fs_info->delalloc_workers);
 	btrfs_destroy_workqueue(fs_info->workers);
 	btrfs_stop_workers(&fs_info->endio_workers);
 	btrfs_stop_workers(&fs_info->endio_meta_workers);
@@ -2476,8 +2476,8 @@ int open_ctree(struct super_block *sb,
 		btrfs_alloc_workqueue("worker", flags | WQ_HIGHPRI,
 				      max_active, 16);
 
-	btrfs_init_workers(&fs_info->delalloc_workers, "delalloc",
-			   fs_info->thread_pool_size, NULL);
+	fs_info->delalloc_workers =
+		btrfs_alloc_workqueue("delalloc", flags, max_active, 2);
 
 	btrfs_init_workers(&fs_info->flush_workers, "flush_delalloc",
 			   fs_info->thread_pool_size, NULL);
@@ -2495,9 +2495,6 @@ int open_ctree(struct super_block *sb,
 	 */
 	fs_info->submit_workers.idle_thresh = 64;
 
-	fs_info->delalloc_workers.idle_thresh = 2;
-	fs_info->delalloc_workers.ordered = 1;
-
 	btrfs_init_workers(&fs_info->fixup_workers, "fixup", 1,
 			   &fs_info->generic_worker);
 	btrfs_init_workers(&fs_info->endio_workers, "endio",
@@ -2548,7 +2545,6 @@ int open_ctree(struct super_block *sb,
 	 */
 	ret = btrfs_start_workers(&fs_info->generic_worker);
 	ret |= btrfs_start_workers(&fs_info->submit_workers);
-	ret |= btrfs_start_workers(&fs_info->delalloc_workers);
 	ret |= btrfs_start_workers(&fs_info->fixup_workers);
 	ret |= btrfs_start_workers(&fs_info->endio_workers);
 	ret |= btrfs_start_workers(&fs_info->endio_meta_workers);
@@ -2566,7 +2562,7 @@ int open_ctree(struct super_block *sb,
 		err = -ENOMEM;
 		goto fail_sb_buffer;
 	}
-	if (!(fs_info->workers)) {
+	if (!(fs_info->workers && fs_info->delalloc_workers)) {
 		err = -ENOMEM;
 		goto fail_sb_buffer;
 	}
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 197edee..01cfe99 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -324,7 +324,7 @@ struct async_cow {
 	u64 start;
 	u64 end;
 	struct list_head extents;
-	struct btrfs_work work;
+	struct btrfs_work_struct work;
 };
 
 static noinline int add_async_extent(struct async_cow *cow,
@@ -1000,7 +1000,7 @@ out_unlock:
 /*
  * work queue call back to started compression on a file and pages
  */
-static noinline void async_cow_start(struct btrfs_work *work)
+static noinline void async_cow_start(struct btrfs_work_struct *work)
 {
 	struct async_cow *async_cow;
 	int num_added = 0;
@@ -1018,7 +1018,7 @@ static noinline void async_cow_start(struct btrfs_work *work)
 /*
  * work queue call back to submit previously compressed pages
  */
-static noinline void async_cow_submit(struct btrfs_work *work)
+static noinline void async_cow_submit(struct btrfs_work_struct *work)
 {
 	struct async_cow *async_cow;
 	struct btrfs_root *root;
@@ -1039,7 +1039,7 @@ static noinline void async_cow_submit(struct btrfs_work *work)
 		submit_compressed_extents(async_cow->inode, async_cow);
 }
 
-static noinline void async_cow_free(struct btrfs_work *work)
+static noinline void async_cow_free(struct btrfs_work_struct *work)
 {
 	struct async_cow *async_cow;
 	async_cow = container_of(work, struct async_cow, work);
@@ -1076,17 +1076,15 @@ static int cow_file_range_async(struct inode *inode, struct page *locked_page,
 		async_cow->end = cur_end;
 		INIT_LIST_HEAD(&async_cow->extents);
 
-		async_cow->work.func = async_cow_start;
-		async_cow->work.ordered_func = async_cow_submit;
-		async_cow->work.ordered_free = async_cow_free;
-		async_cow->work.flags = 0;
+		btrfs_init_work(&async_cow->work, async_cow_start,
+				async_cow_submit, async_cow_free);
 
 		nr_pages = (cur_end - start + PAGE_CACHE_SIZE) >>
 			PAGE_CACHE_SHIFT;
 		atomic_add(nr_pages, &root->fs_info->async_delalloc_pages);
 
-		btrfs_queue_worker(&root->fs_info->delalloc_workers,
-				   &async_cow->work);
+		btrfs_queue_work(root->fs_info->delalloc_workers,
+				 &async_cow->work);
 
 		if (atomic_read(&root->fs_info->async_delalloc_pages) > limit) {
 			wait_event(root->fs_info->async_submit_wait,
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 7039d3d7..e164d13 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -1318,7 +1318,7 @@ static void btrfs_resize_thread_pool(struct btrfs_fs_info *fs_info,
 
 	btrfs_set_max_workers(&fs_info->generic_worker, new_pool_size);
 	btrfs_workqueue_set_max(fs_info->workers, new_pool_size);
-	btrfs_set_max_workers(&fs_info->delalloc_workers, new_pool_size);
+	btrfs_workqueue_set_max(fs_info->delalloc_workers, new_pool_size);
 	btrfs_set_max_workers(&fs_info->submit_workers, new_pool_size);
 	btrfs_set_max_workers(&fs_info->caching_workers, new_pool_size);
 	btrfs_set_max_workers(&fs_info->fixup_workers, new_pool_size);
-- 
1.9.0

[PATCH v5 07/18] btrfs: Replace fs_info->submit_workers with btrfs_workqueue.

[Qu Wenruo]

Much like the fs_info->workers, replace the fs_info->submit_workers
use the same btrfs_workqueue.

Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Tested-by: David Sterba <dsterba@suse.cz>
---
Changelog:
v1->v2:
  None
v2->v3:
  None
v3->v4:
  - Use the simplified btrfs_alloc_workqueue API.
v4->v5:
  None
---
 fs/btrfs/ctree.h   |  2 +-
 fs/btrfs/disk-io.c | 17 +++++++++--------
 fs/btrfs/super.c   |  2 +-
 fs/btrfs/volumes.c | 11 ++++++-----
 fs/btrfs/volumes.h |  2 +-
 5 files changed, 18 insertions(+), 16 deletions(-)

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 4e11f4b..9af6804 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1515,7 +1515,7 @@ struct btrfs_fs_info {
 	struct btrfs_workers endio_meta_write_workers;
 	struct btrfs_workers endio_write_workers;
 	struct btrfs_workers endio_freespace_worker;
-	struct btrfs_workers submit_workers;
+	struct btrfs_workqueue_struct *submit_workers;
 	struct btrfs_workers caching_workers;
 	struct btrfs_workers readahead_workers;
 
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index f97bd17..8b118ed 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -2002,7 +2002,7 @@ static void btrfs_stop_all_workers(struct btrfs_fs_info *fs_info)
 	btrfs_stop_workers(&fs_info->endio_meta_write_workers);
 	btrfs_stop_workers(&fs_info->endio_write_workers);
 	btrfs_stop_workers(&fs_info->endio_freespace_worker);
-	btrfs_stop_workers(&fs_info->submit_workers);
+	btrfs_destroy_workqueue(fs_info->submit_workers);
 	btrfs_stop_workers(&fs_info->delayed_workers);
 	btrfs_stop_workers(&fs_info->caching_workers);
 	btrfs_stop_workers(&fs_info->readahead_workers);
@@ -2482,18 +2482,19 @@ int open_ctree(struct super_block *sb,
 	btrfs_init_workers(&fs_info->flush_workers, "flush_delalloc",
 			   fs_info->thread_pool_size, NULL);
 
-	btrfs_init_workers(&fs_info->submit_workers, "submit",
-			   min_t(u64, fs_devices->num_devices,
-			   fs_info->thread_pool_size), NULL);
 
 	btrfs_init_workers(&fs_info->caching_workers, "cache",
 			   fs_info->thread_pool_size, NULL);
 
-	/* a higher idle thresh on the submit workers makes it much more
+	/*
+	 * a higher idle thresh on the submit workers makes it much more
 	 * likely that bios will be send down in a sane order to the
 	 * devices
 	 */
-	fs_info->submit_workers.idle_thresh = 64;
+	fs_info->submit_workers =
+		btrfs_alloc_workqueue("submit", flags,
+				      min_t(u64, fs_devices->num_devices,
+					    max_active), 64);
 
 	btrfs_init_workers(&fs_info->fixup_workers, "fixup", 1,
 			   &fs_info->generic_worker);
@@ -2544,7 +2545,6 @@ int open_ctree(struct super_block *sb,
 	 * return -ENOMEM if any of these fail.
 	 */
 	ret = btrfs_start_workers(&fs_info->generic_worker);
-	ret |= btrfs_start_workers(&fs_info->submit_workers);
 	ret |= btrfs_start_workers(&fs_info->fixup_workers);
 	ret |= btrfs_start_workers(&fs_info->endio_workers);
 	ret |= btrfs_start_workers(&fs_info->endio_meta_workers);
@@ -2562,7 +2562,8 @@ int open_ctree(struct super_block *sb,
 		err = -ENOMEM;
 		goto fail_sb_buffer;
 	}
-	if (!(fs_info->workers && fs_info->delalloc_workers)) {
+	if (!(fs_info->workers && fs_info->delalloc_workers &&
+	      fs_info->submit_workers)) {
 		err = -ENOMEM;
 		goto fail_sb_buffer;
 	}
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index e164d13..2d69b6d 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -1319,7 +1319,7 @@ static void btrfs_resize_thread_pool(struct btrfs_fs_info *fs_info,
 	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);
-	btrfs_set_max_workers(&fs_info->submit_workers, new_pool_size);
+	btrfs_workqueue_set_max(fs_info->submit_workers, new_pool_size);
 	btrfs_set_max_workers(&fs_info->caching_workers, new_pool_size);
 	btrfs_set_max_workers(&fs_info->fixup_workers, new_pool_size);
 	btrfs_set_max_workers(&fs_info->endio_workers, new_pool_size);
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 82a63b1..0066cff 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -415,7 +415,8 @@ loop_lock:
 			device->running_pending = 1;
 
 			spin_unlock(&device->io_lock);
-			btrfs_requeue_work(&device->work);
+			btrfs_queue_work(fs_info->submit_workers,
+					 &device->work);
 			goto done;
 		}
 		/* unplug every 64 requests just for good measure */
@@ -439,7 +440,7 @@ done:
 	blk_finish_plug(&plug);
 }
 
-static void pending_bios_fn(struct btrfs_work *work)
+static void pending_bios_fn(struct btrfs_work_struct *work)
 {
 	struct btrfs_device *device;
 
@@ -5379,8 +5380,8 @@ static noinline void btrfs_schedule_bio(struct btrfs_root *root,
 	spin_unlock(&device->io_lock);
 
 	if (should_queue)
-		btrfs_queue_worker(&root->fs_info->submit_workers,
-				   &device->work);
+		btrfs_queue_work(root->fs_info->submit_workers,
+				 &device->work);
 }
 
 static int bio_size_ok(struct block_device *bdev, struct bio *bio,
@@ -5668,7 +5669,7 @@ struct btrfs_device *btrfs_alloc_device(struct btrfs_fs_info *fs_info,
 	else
 		generate_random_uuid(dev->uuid);
 
-	dev->work.func = pending_bios_fn;
+	btrfs_init_work(&dev->work, pending_bios_fn, NULL, NULL);
 
 	return dev;
 }
diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index 80754f9..5d9a037 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -95,7 +95,7 @@ struct btrfs_device {
 	/* per-device scrub information */
 	struct scrub_ctx *scrub_device;
 
-	struct btrfs_work work;
+	struct btrfs_work_struct work;
 	struct rcu_head rcu;
 	struct work_struct rcu_work;
 
-- 
1.9.0

[PATCH v5 08/18] btrfs: Replace fs_info->flush_workers with btrfs_workqueue.

[Qu Wenruo]

Replace the fs_info->submit_workers with the newly created
btrfs_workqueue.

Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Tested-by: David Sterba <dsterba@suse.cz>
---
Changelog:
v1->v2:
  None
v2->v3:
  - Use the btrfs_workqueue_struct to replace submit_workers.
v3->v4:
  - Use the simplified btrfs_alloc_workqueue API.
v4->v5:
  None
---
 fs/btrfs/ctree.h        |  4 ++--
 fs/btrfs/disk-io.c      | 10 ++++------
 fs/btrfs/inode.c        |  8 ++++----
 fs/btrfs/ordered-data.c | 13 +++++++------
 fs/btrfs/ordered-data.h |  2 +-
 5 files changed, 18 insertions(+), 19 deletions(-)

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 9af6804..f1377c9 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1507,7 +1507,7 @@ struct btrfs_fs_info {
 	struct btrfs_workers generic_worker;
 	struct btrfs_workqueue_struct *workers;
 	struct btrfs_workqueue_struct *delalloc_workers;
-	struct btrfs_workers flush_workers;
+	struct btrfs_workqueue_struct *flush_workers;
 	struct btrfs_workers endio_workers;
 	struct btrfs_workers endio_meta_workers;
 	struct btrfs_workers endio_raid56_workers;
@@ -3677,7 +3677,7 @@ struct btrfs_delalloc_work {
 	int delay_iput;
 	struct completion completion;
 	struct list_head list;
-	struct btrfs_work work;
+	struct btrfs_work_struct work;
 };
 
 struct btrfs_delalloc_work *btrfs_alloc_delalloc_work(struct inode *inode,
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 8b118ed..772fa39 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -2006,7 +2006,7 @@ static void btrfs_stop_all_workers(struct btrfs_fs_info *fs_info)
 	btrfs_stop_workers(&fs_info->delayed_workers);
 	btrfs_stop_workers(&fs_info->caching_workers);
 	btrfs_stop_workers(&fs_info->readahead_workers);
-	btrfs_stop_workers(&fs_info->flush_workers);
+	btrfs_destroy_workqueue(fs_info->flush_workers);
 	btrfs_stop_workers(&fs_info->qgroup_rescan_workers);
 }
 
@@ -2479,9 +2479,8 @@ int open_ctree(struct super_block *sb,
 	fs_info->delalloc_workers =
 		btrfs_alloc_workqueue("delalloc", flags, max_active, 2);
 
-	btrfs_init_workers(&fs_info->flush_workers, "flush_delalloc",
-			   fs_info->thread_pool_size, NULL);
-
+	fs_info->flush_workers =
+		btrfs_alloc_workqueue("flush_delalloc", flags, max_active, 0);
 
 	btrfs_init_workers(&fs_info->caching_workers, "cache",
 			   fs_info->thread_pool_size, NULL);
@@ -2556,14 +2555,13 @@ int open_ctree(struct super_block *sb,
 	ret |= btrfs_start_workers(&fs_info->delayed_workers);
 	ret |= btrfs_start_workers(&fs_info->caching_workers);
 	ret |= btrfs_start_workers(&fs_info->readahead_workers);
-	ret |= btrfs_start_workers(&fs_info->flush_workers);
 	ret |= btrfs_start_workers(&fs_info->qgroup_rescan_workers);
 	if (ret) {
 		err = -ENOMEM;
 		goto fail_sb_buffer;
 	}
 	if (!(fs_info->workers && fs_info->delalloc_workers &&
-	      fs_info->submit_workers)) {
+	      fs_info->submit_workers && fs_info->flush_workers)) {
 		err = -ENOMEM;
 		goto fail_sb_buffer;
 	}
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 01cfe99..7627b60 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -8372,7 +8372,7 @@ out_notrans:
 	return ret;
 }
 
-static void btrfs_run_delalloc_work(struct btrfs_work *work)
+static void btrfs_run_delalloc_work(struct btrfs_work_struct *work)
 {
 	struct btrfs_delalloc_work *delalloc_work;
 	struct inode *inode;
@@ -8410,7 +8410,7 @@ struct btrfs_delalloc_work *btrfs_alloc_delalloc_work(struct inode *inode,
 	work->inode = inode;
 	work->wait = wait;
 	work->delay_iput = delay_iput;
-	work->work.func = btrfs_run_delalloc_work;
+	btrfs_init_work(&work->work, btrfs_run_delalloc_work, NULL, NULL);
 
 	return work;
 }
@@ -8462,8 +8462,8 @@ static int __start_delalloc_inodes(struct btrfs_root *root, int delay_iput)
 			goto out;
 		}
 		list_add_tail(&work->list, &works);
-		btrfs_queue_worker(&root->fs_info->flush_workers,
-				   &work->work);
+		btrfs_queue_work(root->fs_info->flush_workers,
+				 &work->work);
 
 		cond_resched();
 		spin_lock(&root->delalloc_lock);
diff --git a/fs/btrfs/ordered-data.c b/fs/btrfs/ordered-data.c
index 138a7d7..6fa8219 100644
--- a/fs/btrfs/ordered-data.c
+++ b/fs/btrfs/ordered-data.c
@@ -576,7 +576,7 @@ void btrfs_remove_ordered_extent(struct inode *inode,
 	wake_up(&entry->wait);
 }
 
-static void btrfs_run_ordered_extent_work(struct btrfs_work *work)
+static void btrfs_run_ordered_extent_work(struct btrfs_work_struct *work)
 {
 	struct btrfs_ordered_extent *ordered;
 
@@ -609,10 +609,11 @@ int btrfs_wait_ordered_extents(struct btrfs_root *root, int nr)
 		atomic_inc(&ordered->refs);
 		spin_unlock(&root->ordered_extent_lock);
 
-		ordered->flush_work.func = btrfs_run_ordered_extent_work;
+		btrfs_init_work(&ordered->flush_work,
+				btrfs_run_ordered_extent_work, NULL, NULL);
 		list_add_tail(&ordered->work_list, &works);
-		btrfs_queue_worker(&root->fs_info->flush_workers,
-				   &ordered->flush_work);
+		btrfs_queue_work(root->fs_info->flush_workers,
+				 &ordered->flush_work);
 
 		cond_resched();
 		spin_lock(&root->ordered_extent_lock);
@@ -725,8 +726,8 @@ int btrfs_run_ordered_operations(struct btrfs_trans_handle *trans,
 			goto out;
 		}
 		list_add_tail(&work->list, &works);
-		btrfs_queue_worker(&root->fs_info->flush_workers,
-				   &work->work);
+		btrfs_queue_work(root->fs_info->flush_workers,
+				 &work->work);
 
 		cond_resched();
 		spin_lock(&root->fs_info->ordered_root_lock);
diff --git a/fs/btrfs/ordered-data.h b/fs/btrfs/ordered-data.h
index 2468970..fe9f4db 100644
--- a/fs/btrfs/ordered-data.h
+++ b/fs/btrfs/ordered-data.h
@@ -133,7 +133,7 @@ struct btrfs_ordered_extent {
 	struct btrfs_work work;
 
 	struct completion completion;
-	struct btrfs_work flush_work;
+	struct btrfs_work_struct flush_work;
 	struct list_head work_list;
 };
 
-- 
1.9.0

[PATCH v5 09/18] btrfs: Replace fs_info->endio_* workqueue with btrfs_workqueue.

[Qu Wenruo]

Replace the fs_info->endio_* workqueues with the newly created
btrfs_workqueue.

Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Tested-by: David Sterba <dsterba@suse.cz>
---
Changelog:
v1->v2:
  None
v2->v3:
  - Use the btrfs_workqueue_struct to replace submit_workers.
v3->v4:
  - Use the simplified btrfs_alloc_workqueue API.
v4->v5:
  None
---
 fs/btrfs/ctree.h        |  12 +++---
 fs/btrfs/disk-io.c      | 104 +++++++++++++++++++++---------------------------
 fs/btrfs/inode.c        |  20 +++++-----
 fs/btrfs/ordered-data.h |   2 +-
 fs/btrfs/super.c        |  11 ++---
 5 files changed, 68 insertions(+), 81 deletions(-)

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index f1377c9..3db87da 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1508,13 +1508,13 @@ struct btrfs_fs_info {
 	struct btrfs_workqueue_struct *workers;
 	struct btrfs_workqueue_struct *delalloc_workers;
 	struct btrfs_workqueue_struct *flush_workers;
-	struct btrfs_workers endio_workers;
-	struct btrfs_workers endio_meta_workers;
-	struct btrfs_workers endio_raid56_workers;
+	struct btrfs_workqueue_struct *endio_workers;
+	struct btrfs_workqueue_struct *endio_meta_workers;
+	struct btrfs_workqueue_struct *endio_raid56_workers;
 	struct btrfs_workers rmw_workers;
-	struct btrfs_workers endio_meta_write_workers;
-	struct btrfs_workers endio_write_workers;
-	struct btrfs_workers endio_freespace_worker;
+	struct btrfs_workqueue_struct *endio_meta_write_workers;
+	struct btrfs_workqueue_struct *endio_write_workers;
+	struct btrfs_workqueue_struct *endio_freespace_worker;
 	struct btrfs_workqueue_struct *submit_workers;
 	struct btrfs_workers caching_workers;
 	struct btrfs_workers readahead_workers;
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 772fa39..28b303c 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -55,7 +55,7 @@
 #endif
 
 static struct extent_io_ops btree_extent_io_ops;
-static void end_workqueue_fn(struct btrfs_work *work);
+static void end_workqueue_fn(struct btrfs_work_struct *work);
 static void free_fs_root(struct btrfs_root *root);
 static int btrfs_check_super_valid(struct btrfs_fs_info *fs_info,
 				    int read_only);
@@ -86,7 +86,7 @@ struct end_io_wq {
 	int error;
 	int metadata;
 	struct list_head list;
-	struct btrfs_work work;
+	struct btrfs_work_struct work;
 };
 
 /*
@@ -678,32 +678,31 @@ static void end_workqueue_bio(struct bio *bio, int err)
 
 	fs_info = end_io_wq->info;
 	end_io_wq->error = err;
-	end_io_wq->work.func = end_workqueue_fn;
-	end_io_wq->work.flags = 0;
+	btrfs_init_work(&end_io_wq->work, end_workqueue_fn, NULL, NULL);
 
 	if (bio->bi_rw & REQ_WRITE) {
 		if (end_io_wq->metadata == BTRFS_WQ_ENDIO_METADATA)
-			btrfs_queue_worker(&fs_info->endio_meta_write_workers,
-					   &end_io_wq->work);
+			btrfs_queue_work(fs_info->endio_meta_write_workers,
+					 &end_io_wq->work);
 		else if (end_io_wq->metadata == BTRFS_WQ_ENDIO_FREE_SPACE)
-			btrfs_queue_worker(&fs_info->endio_freespace_worker,
-					   &end_io_wq->work);
+			btrfs_queue_work(fs_info->endio_freespace_worker,
+					 &end_io_wq->work);
 		else if (end_io_wq->metadata == BTRFS_WQ_ENDIO_RAID56)
-			btrfs_queue_worker(&fs_info->endio_raid56_workers,
-					   &end_io_wq->work);
+			btrfs_queue_work(fs_info->endio_raid56_workers,
+					 &end_io_wq->work);
 		else
-			btrfs_queue_worker(&fs_info->endio_write_workers,
-					   &end_io_wq->work);
+			btrfs_queue_work(fs_info->endio_write_workers,
+					 &end_io_wq->work);
 	} else {
 		if (end_io_wq->metadata == BTRFS_WQ_ENDIO_RAID56)
-			btrfs_queue_worker(&fs_info->endio_raid56_workers,
-					   &end_io_wq->work);
+			btrfs_queue_work(fs_info->endio_raid56_workers,
+					 &end_io_wq->work);
 		else if (end_io_wq->metadata)
-			btrfs_queue_worker(&fs_info->endio_meta_workers,
-					   &end_io_wq->work);
+			btrfs_queue_work(fs_info->endio_meta_workers,
+					 &end_io_wq->work);
 		else
-			btrfs_queue_worker(&fs_info->endio_workers,
-					   &end_io_wq->work);
+			btrfs_queue_work(fs_info->endio_workers,
+					 &end_io_wq->work);
 	}
 }
 
@@ -1665,7 +1664,7 @@ static int setup_bdi(struct btrfs_fs_info *info, struct backing_dev_info *bdi)
  * called by the kthread helper functions to finally call the bio end_io
  * functions.  This is where read checksum verification actually happens
  */
-static void end_workqueue_fn(struct btrfs_work *work)
+static void end_workqueue_fn(struct btrfs_work_struct *work)
 {
 	struct bio *bio;
 	struct end_io_wq *end_io_wq;
@@ -1995,13 +1994,13 @@ static void btrfs_stop_all_workers(struct btrfs_fs_info *fs_info)
 	btrfs_stop_workers(&fs_info->fixup_workers);
 	btrfs_destroy_workqueue(fs_info->delalloc_workers);
 	btrfs_destroy_workqueue(fs_info->workers);
-	btrfs_stop_workers(&fs_info->endio_workers);
-	btrfs_stop_workers(&fs_info->endio_meta_workers);
-	btrfs_stop_workers(&fs_info->endio_raid56_workers);
+	btrfs_destroy_workqueue(fs_info->endio_workers);
+	btrfs_destroy_workqueue(fs_info->endio_meta_workers);
+	btrfs_destroy_workqueue(fs_info->endio_raid56_workers);
 	btrfs_stop_workers(&fs_info->rmw_workers);
-	btrfs_stop_workers(&fs_info->endio_meta_write_workers);
-	btrfs_stop_workers(&fs_info->endio_write_workers);
-	btrfs_stop_workers(&fs_info->endio_freespace_worker);
+	btrfs_destroy_workqueue(fs_info->endio_meta_write_workers);
+	btrfs_destroy_workqueue(fs_info->endio_write_workers);
+	btrfs_destroy_workqueue(fs_info->endio_freespace_worker);
 	btrfs_destroy_workqueue(fs_info->submit_workers);
 	btrfs_stop_workers(&fs_info->delayed_workers);
 	btrfs_stop_workers(&fs_info->caching_workers);
@@ -2497,26 +2496,26 @@ int open_ctree(struct super_block *sb,
 
 	btrfs_init_workers(&fs_info->fixup_workers, "fixup", 1,
 			   &fs_info->generic_worker);
-	btrfs_init_workers(&fs_info->endio_workers, "endio",
-			   fs_info->thread_pool_size,
-			   &fs_info->generic_worker);
-	btrfs_init_workers(&fs_info->endio_meta_workers, "endio-meta",
-			   fs_info->thread_pool_size,
-			   &fs_info->generic_worker);
-	btrfs_init_workers(&fs_info->endio_meta_write_workers,
-			   "endio-meta-write", fs_info->thread_pool_size,
-			   &fs_info->generic_worker);
-	btrfs_init_workers(&fs_info->endio_raid56_workers,
-			   "endio-raid56", fs_info->thread_pool_size,
-			   &fs_info->generic_worker);
+
+	/*
+	 * endios are largely parallel and should have a very
+	 * low idle thresh
+	 */
+	fs_info->endio_workers =
+		btrfs_alloc_workqueue("endio", flags, max_active, 4);
+	fs_info->endio_meta_workers =
+		btrfs_alloc_workqueue("endio-meta", flags, max_active, 4);
+	fs_info->endio_meta_write_workers =
+		btrfs_alloc_workqueue("endio-meta-write", flags, max_active, 2);
+	fs_info->endio_raid56_workers =
+		btrfs_alloc_workqueue("endio-raid56", flags, max_active, 4);
 	btrfs_init_workers(&fs_info->rmw_workers,
 			   "rmw", fs_info->thread_pool_size,
 			   &fs_info->generic_worker);
-	btrfs_init_workers(&fs_info->endio_write_workers, "endio-write",
-			   fs_info->thread_pool_size,
-			   &fs_info->generic_worker);
-	btrfs_init_workers(&fs_info->endio_freespace_worker, "freespace-write",
-			   1, &fs_info->generic_worker);
+	fs_info->endio_write_workers =
+		btrfs_alloc_workqueue("endio-write", flags, max_active, 2);
+	fs_info->endio_freespace_worker =
+		btrfs_alloc_workqueue("freespace-write", flags, max_active, 0);
 	btrfs_init_workers(&fs_info->delayed_workers, "delayed-meta",
 			   fs_info->thread_pool_size,
 			   &fs_info->generic_worker);
@@ -2526,17 +2525,8 @@ int open_ctree(struct super_block *sb,
 	btrfs_init_workers(&fs_info->qgroup_rescan_workers, "qgroup-rescan", 1,
 			   &fs_info->generic_worker);
 
-	/*
-	 * endios are largely parallel and should have a very
-	 * low idle thresh
-	 */
-	fs_info->endio_workers.idle_thresh = 4;
-	fs_info->endio_meta_workers.idle_thresh = 4;
-	fs_info->endio_raid56_workers.idle_thresh = 4;
 	fs_info->rmw_workers.idle_thresh = 2;
 
-	fs_info->endio_write_workers.idle_thresh = 2;
-	fs_info->endio_meta_write_workers.idle_thresh = 2;
 	fs_info->readahead_workers.idle_thresh = 2;
 
 	/*
@@ -2545,13 +2535,7 @@ int open_ctree(struct super_block *sb,
 	 */
 	ret = btrfs_start_workers(&fs_info->generic_worker);
 	ret |= btrfs_start_workers(&fs_info->fixup_workers);
-	ret |= btrfs_start_workers(&fs_info->endio_workers);
-	ret |= btrfs_start_workers(&fs_info->endio_meta_workers);
 	ret |= btrfs_start_workers(&fs_info->rmw_workers);
-	ret |= btrfs_start_workers(&fs_info->endio_raid56_workers);
-	ret |= btrfs_start_workers(&fs_info->endio_meta_write_workers);
-	ret |= btrfs_start_workers(&fs_info->endio_write_workers);
-	ret |= btrfs_start_workers(&fs_info->endio_freespace_worker);
 	ret |= btrfs_start_workers(&fs_info->delayed_workers);
 	ret |= btrfs_start_workers(&fs_info->caching_workers);
 	ret |= btrfs_start_workers(&fs_info->readahead_workers);
@@ -2561,7 +2545,11 @@ int open_ctree(struct super_block *sb,
 		goto fail_sb_buffer;
 	}
 	if (!(fs_info->workers && fs_info->delalloc_workers &&
-	      fs_info->submit_workers && fs_info->flush_workers)) {
+	      fs_info->submit_workers && fs_info->flush_workers &&
+	      fs_info->endio_workers && fs_info->endio_meta_workers &&
+	      fs_info->endio_meta_write_workers &&
+	      fs_info->endio_write_workers && fs_info->endio_raid56_workers &&
+	      fs_info->endio_freespace_worker)) {
 		err = -ENOMEM;
 		goto fail_sb_buffer;
 	}
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 7627b60..4023c90 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -2750,7 +2750,7 @@ out:
 	return ret;
 }
 
-static void finish_ordered_fn(struct btrfs_work *work)
+static void finish_ordered_fn(struct btrfs_work_struct *work)
 {
 	struct btrfs_ordered_extent *ordered_extent;
 	ordered_extent = container_of(work, struct btrfs_ordered_extent, work);
@@ -2763,7 +2763,7 @@ static int btrfs_writepage_end_io_hook(struct page *page, u64 start, u64 end,
 	struct inode *inode = page->mapping->host;
 	struct btrfs_root *root = BTRFS_I(inode)->root;
 	struct btrfs_ordered_extent *ordered_extent = NULL;
-	struct btrfs_workers *workers;
+	struct btrfs_workqueue_struct *workers;
 
 	trace_btrfs_writepage_end_io_hook(page, start, end, uptodate);
 
@@ -2772,14 +2772,13 @@ static int btrfs_writepage_end_io_hook(struct page *page, u64 start, u64 end,
 					    end - start + 1, uptodate))
 		return 0;
 
-	ordered_extent->work.func = finish_ordered_fn;
-	ordered_extent->work.flags = 0;
+	btrfs_init_work(&ordered_extent->work, finish_ordered_fn, NULL, NULL);
 
 	if (btrfs_is_free_space_inode(inode))
-		workers = &root->fs_info->endio_freespace_worker;
+		workers = root->fs_info->endio_freespace_worker;
 	else
-		workers = &root->fs_info->endio_write_workers;
-	btrfs_queue_worker(workers, &ordered_extent->work);
+		workers = root->fs_info->endio_write_workers;
+	btrfs_queue_work(workers, &ordered_extent->work);
 
 	return 0;
 }
@@ -7032,10 +7031,9 @@ again:
 	if (!ret)
 		goto out_test;
 
-	ordered->work.func = finish_ordered_fn;
-	ordered->work.flags = 0;
-	btrfs_queue_worker(&root->fs_info->endio_write_workers,
-			   &ordered->work);
+	btrfs_init_work(&ordered->work, finish_ordered_fn, NULL, NULL);
+	btrfs_queue_work(root->fs_info->endio_write_workers,
+			 &ordered->work);
 out_test:
 	/*
 	 * our bio might span multiple ordered extents.  If we haven't
diff --git a/fs/btrfs/ordered-data.h b/fs/btrfs/ordered-data.h
index fe9f4db..84bb236 100644
--- a/fs/btrfs/ordered-data.h
+++ b/fs/btrfs/ordered-data.h
@@ -130,7 +130,7 @@ struct btrfs_ordered_extent {
 	/* a per root list of all the pending ordered extents */
 	struct list_head root_extent_list;
 
-	struct btrfs_work work;
+	struct btrfs_work_struct work;
 
 	struct completion completion;
 	struct btrfs_work_struct flush_work;
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 2d69b6d..919eb36 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -1322,11 +1322,12 @@ static void btrfs_resize_thread_pool(struct btrfs_fs_info *fs_info,
 	btrfs_workqueue_set_max(fs_info->submit_workers, new_pool_size);
 	btrfs_set_max_workers(&fs_info->caching_workers, new_pool_size);
 	btrfs_set_max_workers(&fs_info->fixup_workers, new_pool_size);
-	btrfs_set_max_workers(&fs_info->endio_workers, new_pool_size);
-	btrfs_set_max_workers(&fs_info->endio_meta_workers, new_pool_size);
-	btrfs_set_max_workers(&fs_info->endio_meta_write_workers, new_pool_size);
-	btrfs_set_max_workers(&fs_info->endio_write_workers, new_pool_size);
-	btrfs_set_max_workers(&fs_info->endio_freespace_worker, new_pool_size);
+	btrfs_workqueue_set_max(fs_info->endio_workers, new_pool_size);
+	btrfs_workqueue_set_max(fs_info->endio_meta_workers, new_pool_size);
+	btrfs_workqueue_set_max(fs_info->endio_meta_write_workers,
+				new_pool_size);
+	btrfs_workqueue_set_max(fs_info->endio_write_workers, new_pool_size);
+	btrfs_workqueue_set_max(fs_info->endio_freespace_worker, new_pool_size);
 	btrfs_set_max_workers(&fs_info->delayed_workers, new_pool_size);
 	btrfs_set_max_workers(&fs_info->readahead_workers, new_pool_size);
 	btrfs_set_max_workers(&fs_info->scrub_wr_completion_workers,
-- 
1.9.0

[PATCH v5 10/18] btrfs: Replace fs_info->rmw_workers workqueue with btrfs_workqueue.

[Qu Wenruo]

Replace the fs_info->rmw_workers with the newly created
btrfs_workqueue.

Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Tested-by: David Sterba <dsterba@suse.cz>
---
Changelog:
v1->v2:
  None
v2->v3:
  - Use the btrfs_workqueue_struct to replace submit_workers.
v3->v4:
  - Use the simplified btrfs_alloc_workqueue API.
v4->v5:
  None
---
 fs/btrfs/ctree.h   |  2 +-
 fs/btrfs/disk-io.c | 12 ++++--------
 fs/btrfs/raid56.c  | 35 ++++++++++++++++-------------------
 3 files changed, 21 insertions(+), 28 deletions(-)

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 3db87da..a7b0bdd 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1511,7 +1511,7 @@ struct btrfs_fs_info {
 	struct btrfs_workqueue_struct *endio_workers;
 	struct btrfs_workqueue_struct *endio_meta_workers;
 	struct btrfs_workqueue_struct *endio_raid56_workers;
-	struct btrfs_workers rmw_workers;
+	struct btrfs_workqueue_struct *rmw_workers;
 	struct btrfs_workqueue_struct *endio_meta_write_workers;
 	struct btrfs_workqueue_struct *endio_write_workers;
 	struct btrfs_workqueue_struct *endio_freespace_worker;
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 28b303c..12586b1 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1997,7 +1997,7 @@ static void btrfs_stop_all_workers(struct btrfs_fs_info *fs_info)
 	btrfs_destroy_workqueue(fs_info->endio_workers);
 	btrfs_destroy_workqueue(fs_info->endio_meta_workers);
 	btrfs_destroy_workqueue(fs_info->endio_raid56_workers);
-	btrfs_stop_workers(&fs_info->rmw_workers);
+	btrfs_destroy_workqueue(fs_info->rmw_workers);
 	btrfs_destroy_workqueue(fs_info->endio_meta_write_workers);
 	btrfs_destroy_workqueue(fs_info->endio_write_workers);
 	btrfs_destroy_workqueue(fs_info->endio_freespace_worker);
@@ -2509,9 +2509,8 @@ int open_ctree(struct super_block *sb,
 		btrfs_alloc_workqueue("endio-meta-write", flags, max_active, 2);
 	fs_info->endio_raid56_workers =
 		btrfs_alloc_workqueue("endio-raid56", flags, max_active, 4);
-	btrfs_init_workers(&fs_info->rmw_workers,
-			   "rmw", fs_info->thread_pool_size,
-			   &fs_info->generic_worker);
+	fs_info->rmw_workers =
+		btrfs_alloc_workqueue("rmw", flags, max_active, 2);
 	fs_info->endio_write_workers =
 		btrfs_alloc_workqueue("endio-write", flags, max_active, 2);
 	fs_info->endio_freespace_worker =
@@ -2525,8 +2524,6 @@ int open_ctree(struct super_block *sb,
 	btrfs_init_workers(&fs_info->qgroup_rescan_workers, "qgroup-rescan", 1,
 			   &fs_info->generic_worker);
 
-	fs_info->rmw_workers.idle_thresh = 2;
-
 	fs_info->readahead_workers.idle_thresh = 2;
 
 	/*
@@ -2535,7 +2532,6 @@ int open_ctree(struct super_block *sb,
 	 */
 	ret = btrfs_start_workers(&fs_info->generic_worker);
 	ret |= btrfs_start_workers(&fs_info->fixup_workers);
-	ret |= btrfs_start_workers(&fs_info->rmw_workers);
 	ret |= btrfs_start_workers(&fs_info->delayed_workers);
 	ret |= btrfs_start_workers(&fs_info->caching_workers);
 	ret |= btrfs_start_workers(&fs_info->readahead_workers);
@@ -2549,7 +2545,7 @@ int open_ctree(struct super_block *sb,
 	      fs_info->endio_workers && fs_info->endio_meta_workers &&
 	      fs_info->endio_meta_write_workers &&
 	      fs_info->endio_write_workers && fs_info->endio_raid56_workers &&
-	      fs_info->endio_freespace_worker)) {
+	      fs_info->endio_freespace_worker && fs_info->rmw_workers)) {
 		err = -ENOMEM;
 		goto fail_sb_buffer;
 	}
diff --git a/fs/btrfs/raid56.c b/fs/btrfs/raid56.c
index 24ac218..5afa564 100644
--- a/fs/btrfs/raid56.c
+++ b/fs/btrfs/raid56.c
@@ -87,7 +87,7 @@ struct btrfs_raid_bio {
 	/*
 	 * for scheduling work in the helper threads
 	 */
-	struct btrfs_work work;
+	struct btrfs_work_struct work;
 
 	/*
 	 * bio list and bio_list_lock are used
@@ -166,8 +166,8 @@ struct btrfs_raid_bio {
 
 static int __raid56_parity_recover(struct btrfs_raid_bio *rbio);
 static noinline void finish_rmw(struct btrfs_raid_bio *rbio);
-static void rmw_work(struct btrfs_work *work);
-static void read_rebuild_work(struct btrfs_work *work);
+static void rmw_work(struct btrfs_work_struct *work);
+static void read_rebuild_work(struct btrfs_work_struct *work);
 static void async_rmw_stripe(struct btrfs_raid_bio *rbio);
 static void async_read_rebuild(struct btrfs_raid_bio *rbio);
 static int fail_bio_stripe(struct btrfs_raid_bio *rbio, struct bio *bio);
@@ -1416,20 +1416,18 @@ cleanup:
 
 static void async_rmw_stripe(struct btrfs_raid_bio *rbio)
 {
-	rbio->work.flags = 0;
-	rbio->work.func = rmw_work;
+	btrfs_init_work(&rbio->work, rmw_work, NULL, NULL);
 
-	btrfs_queue_worker(&rbio->fs_info->rmw_workers,
-			   &rbio->work);
+	btrfs_queue_work(rbio->fs_info->rmw_workers,
+			 &rbio->work);
 }
 
 static void async_read_rebuild(struct btrfs_raid_bio *rbio)
 {
-	rbio->work.flags = 0;
-	rbio->work.func = read_rebuild_work;
+	btrfs_init_work(&rbio->work, read_rebuild_work, NULL, NULL);
 
-	btrfs_queue_worker(&rbio->fs_info->rmw_workers,
-			   &rbio->work);
+	btrfs_queue_work(rbio->fs_info->rmw_workers,
+			 &rbio->work);
 }
 
 /*
@@ -1590,7 +1588,7 @@ struct btrfs_plug_cb {
 	struct blk_plug_cb cb;
 	struct btrfs_fs_info *info;
 	struct list_head rbio_list;
-	struct btrfs_work work;
+	struct btrfs_work_struct work;
 };
 
 /*
@@ -1654,7 +1652,7 @@ static void run_plug(struct btrfs_plug_cb *plug)
  * if the unplug comes from schedule, we have to push the
  * work off to a helper thread
  */
-static void unplug_work(struct btrfs_work *work)
+static void unplug_work(struct btrfs_work_struct *work)
 {
 	struct btrfs_plug_cb *plug;
 	plug = container_of(work, struct btrfs_plug_cb, work);
@@ -1667,10 +1665,9 @@ static void btrfs_raid_unplug(struct blk_plug_cb *cb, bool from_schedule)
 	plug = container_of(cb, struct btrfs_plug_cb, cb);
 
 	if (from_schedule) {
-		plug->work.flags = 0;
-		plug->work.func = unplug_work;
-		btrfs_queue_worker(&plug->info->rmw_workers,
-				   &plug->work);
+		btrfs_init_work(&plug->work, unplug_work, NULL, NULL);
+		btrfs_queue_work(plug->info->rmw_workers,
+				 &plug->work);
 		return;
 	}
 	run_plug(plug);
@@ -2082,7 +2079,7 @@ int raid56_parity_recover(struct btrfs_root *root, struct bio *bio,
 
 }
 
-static void rmw_work(struct btrfs_work *work)
+static void rmw_work(struct btrfs_work_struct *work)
 {
 	struct btrfs_raid_bio *rbio;
 
@@ -2090,7 +2087,7 @@ static void rmw_work(struct btrfs_work *work)
 	raid56_rmw_stripe(rbio);
 }
 
-static void read_rebuild_work(struct btrfs_work *work)
+static void read_rebuild_work(struct btrfs_work_struct *work)
 {
 	struct btrfs_raid_bio *rbio;
 
-- 
1.9.0

[PATCH v5 11/18] btrfs: Replace fs_info->cache_workers workqueue with btrfs_workqueue.

[Qu Wenruo]

Replace the fs_info->cache_workers with the newly created
btrfs_workqueue.

Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Tested-by: David Sterba <dsterba@suse.cz>
---
Changelog:
v1->v2:
  None
v2->v3:
  - Use the btrfs_workqueue_struct to replace submit_workers.
v3->v4:
  - Use the simplified btrfs_alloc_workqueue API.
v4->v5:
  None
---
 fs/btrfs/ctree.h       |  4 ++--
 fs/btrfs/disk-io.c     | 10 +++++-----
 fs/btrfs/extent-tree.c |  6 +++---
 fs/btrfs/super.c       |  2 +-
 4 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index a7b0bdd..06a64fb 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1221,7 +1221,7 @@ struct btrfs_caching_control {
 	struct list_head list;
 	struct mutex mutex;
 	wait_queue_head_t wait;
-	struct btrfs_work work;
+	struct btrfs_work_struct work;
 	struct btrfs_block_group_cache *block_group;
 	u64 progress;
 	atomic_t count;
@@ -1516,7 +1516,7 @@ struct btrfs_fs_info {
 	struct btrfs_workqueue_struct *endio_write_workers;
 	struct btrfs_workqueue_struct *endio_freespace_worker;
 	struct btrfs_workqueue_struct *submit_workers;
-	struct btrfs_workers caching_workers;
+	struct btrfs_workqueue_struct *caching_workers;
 	struct btrfs_workers readahead_workers;
 
 	/*
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 12586b1..391cadf 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -2003,7 +2003,7 @@ static void btrfs_stop_all_workers(struct btrfs_fs_info *fs_info)
 	btrfs_destroy_workqueue(fs_info->endio_freespace_worker);
 	btrfs_destroy_workqueue(fs_info->submit_workers);
 	btrfs_stop_workers(&fs_info->delayed_workers);
-	btrfs_stop_workers(&fs_info->caching_workers);
+	btrfs_destroy_workqueue(fs_info->caching_workers);
 	btrfs_stop_workers(&fs_info->readahead_workers);
 	btrfs_destroy_workqueue(fs_info->flush_workers);
 	btrfs_stop_workers(&fs_info->qgroup_rescan_workers);
@@ -2481,8 +2481,8 @@ int open_ctree(struct super_block *sb,
 	fs_info->flush_workers =
 		btrfs_alloc_workqueue("flush_delalloc", flags, max_active, 0);
 
-	btrfs_init_workers(&fs_info->caching_workers, "cache",
-			   fs_info->thread_pool_size, NULL);
+	fs_info->caching_workers =
+		btrfs_alloc_workqueue("cache", flags, max_active, 0);
 
 	/*
 	 * a higher idle thresh on the submit workers makes it much more
@@ -2533,7 +2533,6 @@ int open_ctree(struct super_block *sb,
 	ret = btrfs_start_workers(&fs_info->generic_worker);
 	ret |= btrfs_start_workers(&fs_info->fixup_workers);
 	ret |= btrfs_start_workers(&fs_info->delayed_workers);
-	ret |= btrfs_start_workers(&fs_info->caching_workers);
 	ret |= btrfs_start_workers(&fs_info->readahead_workers);
 	ret |= btrfs_start_workers(&fs_info->qgroup_rescan_workers);
 	if (ret) {
@@ -2545,7 +2544,8 @@ int open_ctree(struct super_block *sb,
 	      fs_info->endio_workers && fs_info->endio_meta_workers &&
 	      fs_info->endio_meta_write_workers &&
 	      fs_info->endio_write_workers && fs_info->endio_raid56_workers &&
-	      fs_info->endio_freespace_worker && fs_info->rmw_workers)) {
+	      fs_info->endio_freespace_worker && fs_info->rmw_workers &&
+	      fs_info->caching_workers)) {
 		err = -ENOMEM;
 		goto fail_sb_buffer;
 	}
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 32312e0..bb58082 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -378,7 +378,7 @@ static u64 add_new_free_space(struct btrfs_block_group_cache *block_group,
 	return total_added;
 }
 
-static noinline void caching_thread(struct btrfs_work *work)
+static noinline void caching_thread(struct btrfs_work_struct *work)
 {
 	struct btrfs_block_group_cache *block_group;
 	struct btrfs_fs_info *fs_info;
@@ -549,7 +549,7 @@ static int cache_block_group(struct btrfs_block_group_cache *cache,
 	caching_ctl->block_group = cache;
 	caching_ctl->progress = cache->key.objectid;
 	atomic_set(&caching_ctl->count, 1);
-	caching_ctl->work.func = caching_thread;
+	btrfs_init_work(&caching_ctl->work, caching_thread, NULL, NULL);
 
 	spin_lock(&cache->lock);
 	/*
@@ -640,7 +640,7 @@ static int cache_block_group(struct btrfs_block_group_cache *cache,
 
 	btrfs_get_block_group(cache);
 
-	btrfs_queue_worker(&fs_info->caching_workers, &caching_ctl->work);
+	btrfs_queue_work(fs_info->caching_workers, &caching_ctl->work);
 
 	return ret;
 }
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 919eb36..cd52e20 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -1320,7 +1320,7 @@ static void btrfs_resize_thread_pool(struct btrfs_fs_info *fs_info,
 	btrfs_workqueue_set_max(fs_info->workers, new_pool_size);
 	btrfs_workqueue_set_max(fs_info->delalloc_workers, new_pool_size);
 	btrfs_workqueue_set_max(fs_info->submit_workers, new_pool_size);
-	btrfs_set_max_workers(&fs_info->caching_workers, new_pool_size);
+	btrfs_workqueue_set_max(fs_info->caching_workers, new_pool_size);
 	btrfs_set_max_workers(&fs_info->fixup_workers, new_pool_size);
 	btrfs_workqueue_set_max(fs_info->endio_workers, new_pool_size);
 	btrfs_workqueue_set_max(fs_info->endio_meta_workers, new_pool_size);
-- 
1.9.0

[PATCH v5 12/18] btrfs: Replace fs_info->readahead_workers workqueue with btrfs_workqueue.

[Qu Wenruo]

Replace the fs_info->readahead_workers with the newly created
btrfs_workqueue.

Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Tested-by: David Sterba <dsterba@suse.cz>
---
Changelog:
v1->v2:
  None
v2->v3:
  - Use the btrfs_workqueue_struct to replace submit_workers.
v3->v4:
  - Use the simplified btrfs_alloc_workqueue API.
v4->v5:
  None
---
 fs/btrfs/ctree.h   |  2 +-
 fs/btrfs/disk-io.c | 12 ++++--------
 fs/btrfs/reada.c   |  9 +++++----
 fs/btrfs/super.c   |  2 +-
 4 files changed, 11 insertions(+), 14 deletions(-)

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 06a64fb..3d6f490 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1517,7 +1517,7 @@ struct btrfs_fs_info {
 	struct btrfs_workqueue_struct *endio_freespace_worker;
 	struct btrfs_workqueue_struct *submit_workers;
 	struct btrfs_workqueue_struct *caching_workers;
-	struct btrfs_workers readahead_workers;
+	struct btrfs_workqueue_struct *readahead_workers;
 
 	/*
 	 * fixup workers take dirty pages that didn't properly go through
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 391cadf..ca6d0cf 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -2004,7 +2004,7 @@ static void btrfs_stop_all_workers(struct btrfs_fs_info *fs_info)
 	btrfs_destroy_workqueue(fs_info->submit_workers);
 	btrfs_stop_workers(&fs_info->delayed_workers);
 	btrfs_destroy_workqueue(fs_info->caching_workers);
-	btrfs_stop_workers(&fs_info->readahead_workers);
+	btrfs_destroy_workqueue(fs_info->readahead_workers);
 	btrfs_destroy_workqueue(fs_info->flush_workers);
 	btrfs_stop_workers(&fs_info->qgroup_rescan_workers);
 }
@@ -2518,14 +2518,11 @@ int open_ctree(struct super_block *sb,
 	btrfs_init_workers(&fs_info->delayed_workers, "delayed-meta",
 			   fs_info->thread_pool_size,
 			   &fs_info->generic_worker);
-	btrfs_init_workers(&fs_info->readahead_workers, "readahead",
-			   fs_info->thread_pool_size,
-			   &fs_info->generic_worker);
+	fs_info->readahead_workers =
+		btrfs_alloc_workqueue("readahead", flags, max_active, 2);
 	btrfs_init_workers(&fs_info->qgroup_rescan_workers, "qgroup-rescan", 1,
 			   &fs_info->generic_worker);
 
-	fs_info->readahead_workers.idle_thresh = 2;
-
 	/*
 	 * btrfs_start_workers can really only fail because of ENOMEM so just
 	 * return -ENOMEM if any of these fail.
@@ -2533,7 +2530,6 @@ int open_ctree(struct super_block *sb,
 	ret = btrfs_start_workers(&fs_info->generic_worker);
 	ret |= btrfs_start_workers(&fs_info->fixup_workers);
 	ret |= btrfs_start_workers(&fs_info->delayed_workers);
-	ret |= btrfs_start_workers(&fs_info->readahead_workers);
 	ret |= btrfs_start_workers(&fs_info->qgroup_rescan_workers);
 	if (ret) {
 		err = -ENOMEM;
@@ -2545,7 +2541,7 @@ int open_ctree(struct super_block *sb,
 	      fs_info->endio_meta_write_workers &&
 	      fs_info->endio_write_workers && fs_info->endio_raid56_workers &&
 	      fs_info->endio_freespace_worker && fs_info->rmw_workers &&
-	      fs_info->caching_workers)) {
+	      fs_info->caching_workers && fs_info->readahead_workers)) {
 		err = -ENOMEM;
 		goto fail_sb_buffer;
 	}
diff --git a/fs/btrfs/reada.c b/fs/btrfs/reada.c
index 31c797c..9e01d36 100644
--- a/fs/btrfs/reada.c
+++ b/fs/btrfs/reada.c
@@ -91,7 +91,8 @@ struct reada_zone {
 };
 
 struct reada_machine_work {
-	struct btrfs_work	work;
+	struct btrfs_work_struct
+				work;
 	struct btrfs_fs_info	*fs_info;
 };
 
@@ -733,7 +734,7 @@ static int reada_start_machine_dev(struct btrfs_fs_info *fs_info,
 
 }
 
-static void reada_start_machine_worker(struct btrfs_work *work)
+static void reada_start_machine_worker(struct btrfs_work_struct *work)
 {
 	struct reada_machine_work *rmw;
 	struct btrfs_fs_info *fs_info;
@@ -793,10 +794,10 @@ static void reada_start_machine(struct btrfs_fs_info *fs_info)
 		/* FIXME we cannot handle this properly right now */
 		BUG();
 	}
-	rmw->work.func = reada_start_machine_worker;
+	btrfs_init_work(&rmw->work, reada_start_machine_worker, NULL, NULL);
 	rmw->fs_info = fs_info;
 
-	btrfs_queue_worker(&fs_info->readahead_workers, &rmw->work);
+	btrfs_queue_work(fs_info->readahead_workers, &rmw->work);
 }
 
 #ifdef DEBUG
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index cd52e20..56c5533 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -1329,7 +1329,7 @@ static void btrfs_resize_thread_pool(struct btrfs_fs_info *fs_info,
 	btrfs_workqueue_set_max(fs_info->endio_write_workers, new_pool_size);
 	btrfs_workqueue_set_max(fs_info->endio_freespace_worker, new_pool_size);
 	btrfs_set_max_workers(&fs_info->delayed_workers, new_pool_size);
-	btrfs_set_max_workers(&fs_info->readahead_workers, new_pool_size);
+	btrfs_workqueue_set_max(fs_info->readahead_workers, new_pool_size);
 	btrfs_set_max_workers(&fs_info->scrub_wr_completion_workers,
 			      new_pool_size);
 }
-- 
1.9.0

[PATCH v5 13/18] btrfs: Replace fs_info->fixup_workers workqueue with btrfs_workqueue.

[Qu Wenruo]

Replace the fs_info->fixup_workers with the newly created
btrfs_workqueue.

Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Tested-by: David Sterba <dsterba@suse.cz>
---
Changelog:
v1->v2:
  None
v2->v3:
  - Use the btrfs_workqueue_struct to replace submit_workers.
v3->v4:
  - Use the simplified btrfs_alloc_workqueue API.
v4->v5:
  None
---
 fs/btrfs/ctree.h   |  2 +-
 fs/btrfs/disk-io.c | 10 +++++-----
 fs/btrfs/inode.c   |  8 ++++----
 fs/btrfs/super.c   |  1 -
 4 files changed, 10 insertions(+), 11 deletions(-)

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 3d6f490..95a1e66 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1524,7 +1524,7 @@ struct btrfs_fs_info {
 	 * the cow mechanism and make them safe to write.  It happens
 	 * for the sys_munmap function call path
 	 */
-	struct btrfs_workers fixup_workers;
+	struct btrfs_workqueue_struct *fixup_workers;
 	struct btrfs_workers delayed_workers;
 	struct task_struct *transaction_kthread;
 	struct task_struct *cleaner_kthread;
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index ca6d0cf..4da34df 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1991,7 +1991,7 @@ static noinline int next_root_backup(struct btrfs_fs_info *info,
 static void btrfs_stop_all_workers(struct btrfs_fs_info *fs_info)
 {
 	btrfs_stop_workers(&fs_info->generic_worker);
-	btrfs_stop_workers(&fs_info->fixup_workers);
+	btrfs_destroy_workqueue(fs_info->fixup_workers);
 	btrfs_destroy_workqueue(fs_info->delalloc_workers);
 	btrfs_destroy_workqueue(fs_info->workers);
 	btrfs_destroy_workqueue(fs_info->endio_workers);
@@ -2494,8 +2494,8 @@ int open_ctree(struct super_block *sb,
 				      min_t(u64, fs_devices->num_devices,
 					    max_active), 64);
 
-	btrfs_init_workers(&fs_info->fixup_workers, "fixup", 1,
-			   &fs_info->generic_worker);
+	fs_info->fixup_workers =
+		btrfs_alloc_workqueue("fixup", flags, 1, 0);
 
 	/*
 	 * endios are largely parallel and should have a very
@@ -2528,7 +2528,6 @@ int open_ctree(struct super_block *sb,
 	 * return -ENOMEM if any of these fail.
 	 */
 	ret = btrfs_start_workers(&fs_info->generic_worker);
-	ret |= btrfs_start_workers(&fs_info->fixup_workers);
 	ret |= btrfs_start_workers(&fs_info->delayed_workers);
 	ret |= btrfs_start_workers(&fs_info->qgroup_rescan_workers);
 	if (ret) {
@@ -2541,7 +2540,8 @@ int open_ctree(struct super_block *sb,
 	      fs_info->endio_meta_write_workers &&
 	      fs_info->endio_write_workers && fs_info->endio_raid56_workers &&
 	      fs_info->endio_freespace_worker && fs_info->rmw_workers &&
-	      fs_info->caching_workers && fs_info->readahead_workers)) {
+	      fs_info->caching_workers && fs_info->readahead_workers &&
+	      fs_info->fixup_workers)) {
 		err = -ENOMEM;
 		goto fail_sb_buffer;
 	}
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 4023c90..81395d6 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -1748,10 +1748,10 @@ int btrfs_set_extent_delalloc(struct inode *inode, u64 start, u64 end,
 /* see btrfs_writepage_start_hook for details on why this is required */
 struct btrfs_writepage_fixup {
 	struct page *page;
-	struct btrfs_work work;
+	struct btrfs_work_struct work;
 };
 
-static void btrfs_writepage_fixup_worker(struct btrfs_work *work)
+static void btrfs_writepage_fixup_worker(struct btrfs_work_struct *work)
 {
 	struct btrfs_writepage_fixup *fixup;
 	struct btrfs_ordered_extent *ordered;
@@ -1842,9 +1842,9 @@ static int btrfs_writepage_start_hook(struct page *page, u64 start, u64 end)
 
 	SetPageChecked(page);
 	page_cache_get(page);
-	fixup->work.func = btrfs_writepage_fixup_worker;
+	btrfs_init_work(&fixup->work, btrfs_writepage_fixup_worker, NULL, NULL);
 	fixup->page = page;
-	btrfs_queue_worker(&root->fs_info->fixup_workers, &fixup->work);
+	btrfs_queue_work(root->fs_info->fixup_workers, &fixup->work);
 	return -EBUSY;
 }
 
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 56c5533..3614053 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -1321,7 +1321,6 @@ static void btrfs_resize_thread_pool(struct btrfs_fs_info *fs_info,
 	btrfs_workqueue_set_max(fs_info->delalloc_workers, new_pool_size);
 	btrfs_workqueue_set_max(fs_info->submit_workers, new_pool_size);
 	btrfs_workqueue_set_max(fs_info->caching_workers, new_pool_size);
-	btrfs_set_max_workers(&fs_info->fixup_workers, new_pool_size);
 	btrfs_workqueue_set_max(fs_info->endio_workers, new_pool_size);
 	btrfs_workqueue_set_max(fs_info->endio_meta_workers, new_pool_size);
 	btrfs_workqueue_set_max(fs_info->endio_meta_write_workers,
-- 
1.9.0

[PATCH v5 14/18] btrfs: Replace fs_info->delayed_workers workqueue with btrfs_workqueue.

[Qu Wenruo]

Replace the fs_info->delayed_workers with the newly created
btrfs_workqueue.

Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Tested-by: David Sterba <dsterba@suse.cz>
---
Changelog:
v1->v2:
  None
v2->v3:
  - Use the btrfs_workqueue_struct to replace submit_workers.
v3->v4:
  - Use the simplified btrfs_alloc_workqueue API.
v4->v5:
  None
---
 fs/btrfs/ctree.h         |  2 +-
 fs/btrfs/delayed-inode.c | 10 +++++-----
 fs/btrfs/disk-io.c       | 10 ++++------
 fs/btrfs/super.c         |  2 +-
 4 files changed, 11 insertions(+), 13 deletions(-)

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 95a1e66..07b563d 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1525,7 +1525,7 @@ struct btrfs_fs_info {
 	 * for the sys_munmap function call path
 	 */
 	struct btrfs_workqueue_struct *fixup_workers;
-	struct btrfs_workers delayed_workers;
+	struct btrfs_workqueue_struct *delayed_workers;
 	struct task_struct *transaction_kthread;
 	struct task_struct *cleaner_kthread;
 	int thread_pool_size;
diff --git a/fs/btrfs/delayed-inode.c b/fs/btrfs/delayed-inode.c
index 451b00c..76e85d6 100644
--- a/fs/btrfs/delayed-inode.c
+++ b/fs/btrfs/delayed-inode.c
@@ -1318,10 +1318,10 @@ void btrfs_remove_delayed_node(struct inode *inode)
 struct btrfs_async_delayed_work {
 	struct btrfs_delayed_root *delayed_root;
 	int nr;
-	struct btrfs_work work;
+	struct btrfs_work_struct work;
 };
 
-static void btrfs_async_run_delayed_root(struct btrfs_work *work)
+static void btrfs_async_run_delayed_root(struct btrfs_work_struct *work)
 {
 	struct btrfs_async_delayed_work *async_work;
 	struct btrfs_delayed_root *delayed_root;
@@ -1392,11 +1392,11 @@ static int btrfs_wq_run_delayed_node(struct btrfs_delayed_root *delayed_root,
 		return -ENOMEM;
 
 	async_work->delayed_root = delayed_root;
-	async_work->work.func = btrfs_async_run_delayed_root;
-	async_work->work.flags = 0;
+	btrfs_init_work(&async_work->work, btrfs_async_run_delayed_root,
+			NULL, NULL);
 	async_work->nr = nr;
 
-	btrfs_queue_worker(&root->fs_info->delayed_workers, &async_work->work);
+	btrfs_queue_work(root->fs_info->delayed_workers, &async_work->work);
 	return 0;
 }
 
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 4da34df..ac8e9c2 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -2002,7 +2002,7 @@ static void btrfs_stop_all_workers(struct btrfs_fs_info *fs_info)
 	btrfs_destroy_workqueue(fs_info->endio_write_workers);
 	btrfs_destroy_workqueue(fs_info->endio_freespace_worker);
 	btrfs_destroy_workqueue(fs_info->submit_workers);
-	btrfs_stop_workers(&fs_info->delayed_workers);
+	btrfs_destroy_workqueue(fs_info->delayed_workers);
 	btrfs_destroy_workqueue(fs_info->caching_workers);
 	btrfs_destroy_workqueue(fs_info->readahead_workers);
 	btrfs_destroy_workqueue(fs_info->flush_workers);
@@ -2515,9 +2515,8 @@ int open_ctree(struct super_block *sb,
 		btrfs_alloc_workqueue("endio-write", flags, max_active, 2);
 	fs_info->endio_freespace_worker =
 		btrfs_alloc_workqueue("freespace-write", flags, max_active, 0);
-	btrfs_init_workers(&fs_info->delayed_workers, "delayed-meta",
-			   fs_info->thread_pool_size,
-			   &fs_info->generic_worker);
+	fs_info->delayed_workers =
+		btrfs_alloc_workqueue("delayed-meta", flags, max_active, 0);
 	fs_info->readahead_workers =
 		btrfs_alloc_workqueue("readahead", flags, max_active, 2);
 	btrfs_init_workers(&fs_info->qgroup_rescan_workers, "qgroup-rescan", 1,
@@ -2528,7 +2527,6 @@ int open_ctree(struct super_block *sb,
 	 * return -ENOMEM if any of these fail.
 	 */
 	ret = btrfs_start_workers(&fs_info->generic_worker);
-	ret |= btrfs_start_workers(&fs_info->delayed_workers);
 	ret |= btrfs_start_workers(&fs_info->qgroup_rescan_workers);
 	if (ret) {
 		err = -ENOMEM;
@@ -2541,7 +2539,7 @@ int open_ctree(struct super_block *sb,
 	      fs_info->endio_write_workers && fs_info->endio_raid56_workers &&
 	      fs_info->endio_freespace_worker && fs_info->rmw_workers &&
 	      fs_info->caching_workers && fs_info->readahead_workers &&
-	      fs_info->fixup_workers)) {
+	      fs_info->fixup_workers && fs_info->delayed_workers)) {
 		err = -ENOMEM;
 		goto fail_sb_buffer;
 	}
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 3614053..5a355c4 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -1327,7 +1327,7 @@ static void btrfs_resize_thread_pool(struct btrfs_fs_info *fs_info,
 				new_pool_size);
 	btrfs_workqueue_set_max(fs_info->endio_write_workers, new_pool_size);
 	btrfs_workqueue_set_max(fs_info->endio_freespace_worker, new_pool_size);
-	btrfs_set_max_workers(&fs_info->delayed_workers, new_pool_size);
+	btrfs_workqueue_set_max(fs_info->delayed_workers, new_pool_size);
 	btrfs_workqueue_set_max(fs_info->readahead_workers, new_pool_size);
 	btrfs_set_max_workers(&fs_info->scrub_wr_completion_workers,
 			      new_pool_size);
-- 
1.9.0

[PATCH v5 15/18] btrfs: Replace fs_info->qgroup_rescan_worker workqueue with btrfs_workqueue.

[Qu Wenruo]

Replace the fs_info->qgroup_rescan_worker with the newly created
btrfs_workqueue.

Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Tested-by: David Sterba <dsterba@suse.cz>
---
Changelog:
v1->v2:
  None
v2->v3:
  - Use the btrfs_workqueue_struct to replace submit_workers.
v3->v4:
  - Use the simplified btrfs_alloc_workqueue API.
v4->v5:
  None
---
 fs/btrfs/ctree.h   |  4 ++--
 fs/btrfs/disk-io.c | 10 +++++-----
 fs/btrfs/qgroup.c  | 17 +++++++++--------
 3 files changed, 16 insertions(+), 15 deletions(-)

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 07b563d..f8f62d0 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1648,9 +1648,9 @@ struct btrfs_fs_info {
 	/* qgroup rescan items */
 	struct mutex qgroup_rescan_lock; /* protects the progress item */
 	struct btrfs_key qgroup_rescan_progress;
-	struct btrfs_workers qgroup_rescan_workers;
+	struct btrfs_workqueue_struct *qgroup_rescan_workers;
 	struct completion qgroup_rescan_completion;
-	struct btrfs_work qgroup_rescan_work;
+	struct btrfs_work_struct qgroup_rescan_work;
 
 	/* filesystem state */
 	unsigned long fs_state;
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index ac8e9c2..e3507c5 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -2006,7 +2006,7 @@ static void btrfs_stop_all_workers(struct btrfs_fs_info *fs_info)
 	btrfs_destroy_workqueue(fs_info->caching_workers);
 	btrfs_destroy_workqueue(fs_info->readahead_workers);
 	btrfs_destroy_workqueue(fs_info->flush_workers);
-	btrfs_stop_workers(&fs_info->qgroup_rescan_workers);
+	btrfs_destroy_workqueue(fs_info->qgroup_rescan_workers);
 }
 
 static void free_root_extent_buffers(struct btrfs_root *root)
@@ -2519,15 +2519,14 @@ int open_ctree(struct super_block *sb,
 		btrfs_alloc_workqueue("delayed-meta", flags, max_active, 0);
 	fs_info->readahead_workers =
 		btrfs_alloc_workqueue("readahead", flags, max_active, 2);
-	btrfs_init_workers(&fs_info->qgroup_rescan_workers, "qgroup-rescan", 1,
-			   &fs_info->generic_worker);
+	fs_info->qgroup_rescan_workers =
+		btrfs_alloc_workqueue("qgroup-rescan", flags, 1, 0);
 
 	/*
 	 * 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);
-	ret |= btrfs_start_workers(&fs_info->qgroup_rescan_workers);
 	if (ret) {
 		err = -ENOMEM;
 		goto fail_sb_buffer;
@@ -2539,7 +2538,8 @@ int open_ctree(struct super_block *sb,
 	      fs_info->endio_write_workers && fs_info->endio_raid56_workers &&
 	      fs_info->endio_freespace_worker && fs_info->rmw_workers &&
 	      fs_info->caching_workers && fs_info->readahead_workers &&
-	      fs_info->fixup_workers && fs_info->delayed_workers)) {
+	      fs_info->fixup_workers && fs_info->delayed_workers &&
+	      fs_info->qgroup_rescan_workers)) {
 		err = -ENOMEM;
 		goto fail_sb_buffer;
 	}
diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
index 472302a..38617cc 100644
--- a/fs/btrfs/qgroup.c
+++ b/fs/btrfs/qgroup.c
@@ -1509,8 +1509,8 @@ int btrfs_run_qgroups(struct btrfs_trans_handle *trans,
 		ret = qgroup_rescan_init(fs_info, 0, 1);
 		if (!ret) {
 			qgroup_rescan_zero_tracking(fs_info);
-			btrfs_queue_worker(&fs_info->qgroup_rescan_workers,
-					   &fs_info->qgroup_rescan_work);
+			btrfs_queue_work(fs_info->qgroup_rescan_workers,
+					 &fs_info->qgroup_rescan_work);
 		}
 		ret = 0;
 	}
@@ -1984,7 +1984,7 @@ out:
 	return ret;
 }
 
-static void btrfs_qgroup_rescan_worker(struct btrfs_work *work)
+static void btrfs_qgroup_rescan_worker(struct btrfs_work_struct *work)
 {
 	struct btrfs_fs_info *fs_info = container_of(work, struct btrfs_fs_info,
 						     qgroup_rescan_work);
@@ -2095,7 +2095,8 @@ qgroup_rescan_init(struct btrfs_fs_info *fs_info, u64 progress_objectid,
 
 	memset(&fs_info->qgroup_rescan_work, 0,
 	       sizeof(fs_info->qgroup_rescan_work));
-	fs_info->qgroup_rescan_work.func = btrfs_qgroup_rescan_worker;
+	btrfs_init_work(&fs_info->qgroup_rescan_work,
+			btrfs_qgroup_rescan_worker, NULL, NULL);
 
 	if (ret) {
 err:
@@ -2158,8 +2159,8 @@ btrfs_qgroup_rescan(struct btrfs_fs_info *fs_info)
 
 	qgroup_rescan_zero_tracking(fs_info);
 
-	btrfs_queue_worker(&fs_info->qgroup_rescan_workers,
-			   &fs_info->qgroup_rescan_work);
+	btrfs_queue_work(fs_info->qgroup_rescan_workers,
+			 &fs_info->qgroup_rescan_work);
 
 	return 0;
 }
@@ -2190,6 +2191,6 @@ void
 btrfs_qgroup_rescan_resume(struct btrfs_fs_info *fs_info)
 {
 	if (fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_RESCAN)
-		btrfs_queue_worker(&fs_info->qgroup_rescan_workers,
-				   &fs_info->qgroup_rescan_work);
+		btrfs_queue_work(fs_info->qgroup_rescan_workers,
+				 &fs_info->qgroup_rescan_work);
 }
-- 
1.9.0

[PATCH v5 16/18] btrfs: Replace fs_info->scrub_* workqueue with btrfs_workqueue.

[Qu Wenruo]

Replace the fs_info->scrub_* with the newly created
btrfs_workqueue.

Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Tested-by: David Sterba <dsterba@suse.cz>
---
Changelog:
v1->v2:
  None
v2->v3:
  - Use the btrfs_workqueue_struct to replace submit_workers.
v3->v4:
  - Use the simplified btrfs_alloc_workqueue API.
v4->v5:
  None
---
 fs/btrfs/ctree.h |  6 ++--
 fs/btrfs/scrub.c | 93 ++++++++++++++++++++++++++++++--------------------------
 fs/btrfs/super.c |  4 +--
 3 files changed, 55 insertions(+), 48 deletions(-)

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index f8f62d0..9aece57 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1605,9 +1605,9 @@ struct btrfs_fs_info {
 	atomic_t scrub_cancel_req;
 	wait_queue_head_t scrub_pause_wait;
 	int scrub_workers_refcnt;
-	struct btrfs_workers scrub_workers;
-	struct btrfs_workers scrub_wr_completion_workers;
-	struct btrfs_workers scrub_nocow_workers;
+	struct btrfs_workqueue_struct *scrub_workers;
+	struct btrfs_workqueue_struct *scrub_wr_completion_workers;
+	struct btrfs_workqueue_struct *scrub_nocow_workers;
 
 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
 	u32 check_integrity_print_mask;
diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
index 51c342b..9223b7b 100644
--- a/fs/btrfs/scrub.c
+++ b/fs/btrfs/scrub.c
@@ -96,7 +96,8 @@ struct scrub_bio {
 #endif
 	int			page_count;
 	int			next_free;
-	struct btrfs_work	work;
+	struct btrfs_work_struct
+				work;
 };
 
 struct scrub_block {
@@ -154,7 +155,8 @@ struct scrub_fixup_nodatasum {
 	struct btrfs_device	*dev;
 	u64			logical;
 	struct btrfs_root	*root;
-	struct btrfs_work	work;
+	struct btrfs_work_struct
+				work;
 	int			mirror_num;
 };
 
@@ -172,7 +174,8 @@ struct scrub_copy_nocow_ctx {
 	int			mirror_num;
 	u64			physical_for_dev_replace;
 	struct list_head	inodes;
-	struct btrfs_work	work;
+	struct btrfs_work_struct
+				work;
 };
 
 struct scrub_warning {
@@ -231,7 +234,7 @@ static int scrub_pages(struct scrub_ctx *sctx, u64 logical, u64 len,
 		       u64 gen, int mirror_num, u8 *csum, int force,
 		       u64 physical_for_dev_replace);
 static void scrub_bio_end_io(struct bio *bio, int err);
-static void scrub_bio_end_io_worker(struct btrfs_work *work);
+static void scrub_bio_end_io_worker(struct btrfs_work_struct *work);
 static void scrub_block_complete(struct scrub_block *sblock);
 static void scrub_remap_extent(struct btrfs_fs_info *fs_info,
 			       u64 extent_logical, u64 extent_len,
@@ -248,14 +251,14 @@ static int scrub_add_page_to_wr_bio(struct scrub_ctx *sctx,
 				    struct scrub_page *spage);
 static void scrub_wr_submit(struct scrub_ctx *sctx);
 static void scrub_wr_bio_end_io(struct bio *bio, int err);
-static void scrub_wr_bio_end_io_worker(struct btrfs_work *work);
+static void scrub_wr_bio_end_io_worker(struct btrfs_work_struct *work);
 static int write_page_nocow(struct scrub_ctx *sctx,
 			    u64 physical_for_dev_replace, struct page *page);
 static int copy_nocow_pages_for_inode(u64 inum, u64 offset, u64 root,
 				      struct scrub_copy_nocow_ctx *ctx);
 static int copy_nocow_pages(struct scrub_ctx *sctx, u64 logical, u64 len,
 			    int mirror_num, u64 physical_for_dev_replace);
-static void copy_nocow_pages_worker(struct btrfs_work *work);
+static void copy_nocow_pages_worker(struct btrfs_work_struct *work);
 static void __scrub_blocked_if_needed(struct btrfs_fs_info *fs_info);
 static void scrub_blocked_if_needed(struct btrfs_fs_info *fs_info);
 
@@ -418,7 +421,8 @@ struct scrub_ctx *scrub_setup_ctx(struct btrfs_device *dev, int is_dev_replace)
 		sbio->index = i;
 		sbio->sctx = sctx;
 		sbio->page_count = 0;
-		sbio->work.func = scrub_bio_end_io_worker;
+		btrfs_init_work(&sbio->work, scrub_bio_end_io_worker,
+				NULL, NULL);
 
 		if (i != SCRUB_BIOS_PER_SCTX - 1)
 			sctx->bios[i]->next_free = i + 1;
@@ -723,7 +727,7 @@ out:
 	return -EIO;
 }
 
-static void scrub_fixup_nodatasum(struct btrfs_work *work)
+static void scrub_fixup_nodatasum(struct btrfs_work_struct *work)
 {
 	int ret;
 	struct scrub_fixup_nodatasum *fixup;
@@ -987,9 +991,10 @@ nodatasum_case:
 		fixup_nodatasum->root = fs_info->extent_root;
 		fixup_nodatasum->mirror_num = failed_mirror_index + 1;
 		scrub_pending_trans_workers_inc(sctx);
-		fixup_nodatasum->work.func = scrub_fixup_nodatasum;
-		btrfs_queue_worker(&fs_info->scrub_workers,
-				   &fixup_nodatasum->work);
+		btrfs_init_work(&fixup_nodatasum->work, scrub_fixup_nodatasum,
+				NULL, NULL);
+		btrfs_queue_work(fs_info->scrub_workers,
+				 &fixup_nodatasum->work);
 		goto out;
 	}
 
@@ -1603,11 +1608,11 @@ static void scrub_wr_bio_end_io(struct bio *bio, int err)
 	sbio->err = err;
 	sbio->bio = bio;
 
-	sbio->work.func = scrub_wr_bio_end_io_worker;
-	btrfs_queue_worker(&fs_info->scrub_wr_completion_workers, &sbio->work);
+	btrfs_init_work(&sbio->work, scrub_wr_bio_end_io_worker, NULL, NULL);
+	btrfs_queue_work(fs_info->scrub_wr_completion_workers, &sbio->work);
 }
 
-static void scrub_wr_bio_end_io_worker(struct btrfs_work *work)
+static void scrub_wr_bio_end_io_worker(struct btrfs_work_struct *work)
 {
 	struct scrub_bio *sbio = container_of(work, struct scrub_bio, work);
 	struct scrub_ctx *sctx = sbio->sctx;
@@ -2072,10 +2077,10 @@ static void scrub_bio_end_io(struct bio *bio, int err)
 	sbio->err = err;
 	sbio->bio = bio;
 
-	btrfs_queue_worker(&fs_info->scrub_workers, &sbio->work);
+	btrfs_queue_work(fs_info->scrub_workers, &sbio->work);
 }
 
-static void scrub_bio_end_io_worker(struct btrfs_work *work)
+static void scrub_bio_end_io_worker(struct btrfs_work_struct *work)
 {
 	struct scrub_bio *sbio = container_of(work, struct scrub_bio, work);
 	struct scrub_ctx *sctx = sbio->sctx;
@@ -2757,33 +2762,35 @@ static noinline_for_stack int scrub_workers_get(struct btrfs_fs_info *fs_info,
 						int is_dev_replace)
 {
 	int ret = 0;
+	int flags = WQ_FREEZABLE | WQ_UNBOUND;
+	int max_active = fs_info->thread_pool_size;
 
 	if (fs_info->scrub_workers_refcnt == 0) {
 		if (is_dev_replace)
-			btrfs_init_workers(&fs_info->scrub_workers, "scrub", 1,
-					&fs_info->generic_worker);
+			fs_info->scrub_workers =
+				btrfs_alloc_workqueue("btrfs-scrub", flags,
+						      1, 4);
 		else
-			btrfs_init_workers(&fs_info->scrub_workers, "scrub",
-					fs_info->thread_pool_size,
-					&fs_info->generic_worker);
-		fs_info->scrub_workers.idle_thresh = 4;
-		ret = btrfs_start_workers(&fs_info->scrub_workers);
-		if (ret)
+			fs_info->scrub_workers =
+				btrfs_alloc_workqueue("btrfs-scrub", flags,
+						      max_active, 4);
+		if (!fs_info->scrub_workers) {
+			ret = -ENOMEM;
 			goto out;
-		btrfs_init_workers(&fs_info->scrub_wr_completion_workers,
-				   "scrubwrc",
-				   fs_info->thread_pool_size,
-				   &fs_info->generic_worker);
-		fs_info->scrub_wr_completion_workers.idle_thresh = 2;
-		ret = btrfs_start_workers(
-				&fs_info->scrub_wr_completion_workers);
-		if (ret)
+		}
+		fs_info->scrub_wr_completion_workers =
+			btrfs_alloc_workqueue("btrfs-scrubwrc", flags,
+					      max_active, 2);
+		if (!fs_info->scrub_wr_completion_workers) {
+			ret = -ENOMEM;
 			goto out;
-		btrfs_init_workers(&fs_info->scrub_nocow_workers, "scrubnc", 1,
-				   &fs_info->generic_worker);
-		ret = btrfs_start_workers(&fs_info->scrub_nocow_workers);
-		if (ret)
+		}
+		fs_info->scrub_nocow_workers =
+			btrfs_alloc_workqueue("btrfs-scrubnc", flags, 1, 0);
+		if (!fs_info->scrub_nocow_workers) {
+			ret = -ENOMEM;
 			goto out;
+		}
 	}
 	++fs_info->scrub_workers_refcnt;
 out:
@@ -2793,9 +2800,9 @@ out:
 static noinline_for_stack void scrub_workers_put(struct btrfs_fs_info *fs_info)
 {
 	if (--fs_info->scrub_workers_refcnt == 0) {
-		btrfs_stop_workers(&fs_info->scrub_workers);
-		btrfs_stop_workers(&fs_info->scrub_wr_completion_workers);
-		btrfs_stop_workers(&fs_info->scrub_nocow_workers);
+		btrfs_destroy_workqueue(fs_info->scrub_workers);
+		btrfs_destroy_workqueue(fs_info->scrub_wr_completion_workers);
+		btrfs_destroy_workqueue(fs_info->scrub_nocow_workers);
 	}
 	WARN_ON(fs_info->scrub_workers_refcnt < 0);
 }
@@ -3106,10 +3113,10 @@ static int copy_nocow_pages(struct scrub_ctx *sctx, u64 logical, u64 len,
 	nocow_ctx->len = len;
 	nocow_ctx->mirror_num = mirror_num;
 	nocow_ctx->physical_for_dev_replace = physical_for_dev_replace;
-	nocow_ctx->work.func = copy_nocow_pages_worker;
+	btrfs_init_work(&nocow_ctx->work, copy_nocow_pages_worker, NULL, NULL);
 	INIT_LIST_HEAD(&nocow_ctx->inodes);
-	btrfs_queue_worker(&fs_info->scrub_nocow_workers,
-			   &nocow_ctx->work);
+	btrfs_queue_work(fs_info->scrub_nocow_workers,
+			 &nocow_ctx->work);
 
 	return 0;
 }
@@ -3131,7 +3138,7 @@ static int record_inode_for_nocow(u64 inum, u64 offset, u64 root, void *ctx)
 
 #define COPY_COMPLETE 1
 
-static void copy_nocow_pages_worker(struct btrfs_work *work)
+static void copy_nocow_pages_worker(struct btrfs_work_struct *work)
 {
 	struct scrub_copy_nocow_ctx *nocow_ctx =
 		container_of(work, struct scrub_copy_nocow_ctx, work);
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 5a355c4..655d62e 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -1329,8 +1329,8 @@ static void btrfs_resize_thread_pool(struct btrfs_fs_info *fs_info,
 	btrfs_workqueue_set_max(fs_info->endio_freespace_worker, new_pool_size);
 	btrfs_workqueue_set_max(fs_info->delayed_workers, new_pool_size);
 	btrfs_workqueue_set_max(fs_info->readahead_workers, new_pool_size);
-	btrfs_set_max_workers(&fs_info->scrub_wr_completion_workers,
-			      new_pool_size);
+	btrfs_workqueue_set_max(fs_info->scrub_wr_completion_workers,
+				new_pool_size);
 }
 
 static inline void btrfs_remount_prepare(struct btrfs_fs_info *fs_info)
-- 
1.9.0

[PATCH v5 17/18] btrfs: Cleanup the old btrfs_worker.

[Qu Wenruo]

Since all the btrfs_worker is replaced with the newly created
btrfs_workqueue, the old codes can be easily remove.

Signed-off-by: Quwenruo <quwenruo@cn.fujitsu.com>
Tested-by: David Sterba <dsterba@suse.cz>
---
Changelog:
v1->v2:
  None
v2->v3:
  - Reuse the old async-thred.[ch] files.
v3->v4:
  - Reuse the old WORK_* bits.
v4->v5:
  None
---
 fs/btrfs/async-thread.c | 707 +-----------------------------------------------
 fs/btrfs/async-thread.h | 100 -------
 fs/btrfs/ctree.h        |   1 -
 fs/btrfs/disk-io.c      |  12 -
 fs/btrfs/super.c        |   8 -
 5 files changed, 3 insertions(+), 825 deletions(-)

diff --git a/fs/btrfs/async-thread.c b/fs/btrfs/async-thread.c
index 977bce2..2a5f383 100644
--- a/fs/btrfs/async-thread.c
+++ b/fs/btrfs/async-thread.c
@@ -25,714 +25,13 @@
 #include <linux/workqueue.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
+#define WORK_DONE_BIT 0
+#define WORK_ORDER_DONE_BIT 1
+#define WORK_HIGH_PRIO_BIT 2
 
 #define NO_THRESHOLD (-1)
 #define DFT_THRESHOLD (32)
 
-/*
- * 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) &&
-		    !worker->workers->stopping) {
-			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) &&
-		    !worker->workers->stopping) {
-			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;
-		goto out;
-	}
-
-	smp_mb();
-	if (!list_empty(&worker->prio_pending))
-		goto refill;
-
-	if (!list_empty(head)) {
-		cur = head->next;
-		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);
-	workers->stopping = 1;
-	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;
-	workers->stopping = 0;
-}
-
-/*
- * 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_create(worker_loop, worker,
-				      "btrfs-%s-%d", workers->name,
-				      workers->num_workers + 1);
-	if (IS_ERR(worker->task)) {
-		ret = PTR_ERR(worker->task);
-		goto fail;
-	}
-
-	spin_lock_irq(&workers->lock);
-	if (workers->stopping) {
-		spin_unlock_irq(&workers->lock);
-		ret = -EINVAL;
-		goto fail_kthread;
-	}
-	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);
-
-	wake_up_process(worker->task);
-	return 0;
-
-fail_kthread:
-	kthread_stop(worker->task);
-fail:
-	kfree(worker);
-	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);
-}
-
 struct __btrfs_workqueue_struct {
 	struct workqueue_struct *normal_wq;
 	/* List head pointing to ordered work list */
diff --git a/fs/btrfs/async-thread.h b/fs/btrfs/async-thread.h
index 3129d8a..ab05904 100644
--- a/fs/btrfs/async-thread.h
+++ b/fs/btrfs/async-thread.h
@@ -20,106 +20,6 @@
 #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;
-
-	int stopping;
-};
-
-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);
-
 struct btrfs_workqueue_struct;
 /* Internal use only */
 struct __btrfs_workqueue_struct;
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 9aece57..71bcad0 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1504,7 +1504,6 @@ 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 btrfs_workqueue_struct *flush_workers;
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index e3507c5..9225474 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1990,7 +1990,6 @@ 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->fixup_workers);
 	btrfs_destroy_workqueue(fs_info->delalloc_workers);
 	btrfs_destroy_workqueue(fs_info->workers);
@@ -2468,8 +2467,6 @@ 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", flags | WQ_HIGHPRI,
@@ -2522,15 +2519,6 @@ int open_ctree(struct super_block *sb,
 	fs_info->qgroup_rescan_workers =
 		btrfs_alloc_workqueue("qgroup-rescan", flags, 1, 0);
 
-	/*
-	 * 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) {
-		err = -ENOMEM;
-		goto fail_sb_buffer;
-	}
 	if (!(fs_info->workers && fs_info->delalloc_workers &&
 	      fs_info->submit_workers && fs_info->flush_workers &&
 	      fs_info->endio_workers && fs_info->endio_meta_workers &&
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 655d62e..a3d5776 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -1298,13 +1298,6 @@ 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)
 {
@@ -1316,7 +1309,6 @@ static void btrfs_resize_thread_pool(struct btrfs_fs_info *fs_info,
 	btrfs_info(fs_info, "resize thread pool %d -> %d",
 	       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);
 	btrfs_workqueue_set_max(fs_info->submit_workers, new_pool_size);
-- 
1.9.0

[PATCH v5 18/18] btrfs: Cleanup the "_struct" suffix in btrfs_workequeue

[Qu Wenruo]

Since the "_struct" suffix is mainly used for distinguish the differnt
btrfs_work between the original and the newly created one,
there is no need using the suffix since all btrfs_workers are changed
into btrfs_workqueue.

Also this patch fixed some codes whose code style is changed due to the
too long "_struct" suffix.

Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Tested-by: David Sterba <dsterba@suse.cz>
---
Changelog:
v3->v4:
  - Remove the "_struct" suffix.
v4->v5:
  None
---
 fs/btrfs/async-thread.c  | 66 ++++++++++++++++++++++++------------------------
 fs/btrfs/async-thread.h  | 34 ++++++++++++-------------
 fs/btrfs/ctree.h         | 44 ++++++++++++++++----------------
 fs/btrfs/delayed-inode.c |  4 +--
 fs/btrfs/disk-io.c       | 14 +++++-----
 fs/btrfs/extent-tree.c   |  2 +-
 fs/btrfs/inode.c         | 18 ++++++-------
 fs/btrfs/ordered-data.c  |  2 +-
 fs/btrfs/ordered-data.h  |  4 +--
 fs/btrfs/qgroup.c        |  2 +-
 fs/btrfs/raid56.c        | 14 +++++-----
 fs/btrfs/reada.c         |  5 ++--
 fs/btrfs/scrub.c         | 23 ++++++++---------
 fs/btrfs/volumes.c       |  2 +-
 fs/btrfs/volumes.h       |  2 +-
 15 files changed, 116 insertions(+), 120 deletions(-)

diff --git a/fs/btrfs/async-thread.c b/fs/btrfs/async-thread.c
index 2a5f383..a709585 100644
--- a/fs/btrfs/async-thread.c
+++ b/fs/btrfs/async-thread.c
@@ -32,7 +32,7 @@
 #define NO_THRESHOLD (-1)
 #define DFT_THRESHOLD (32)
 
-struct __btrfs_workqueue_struct {
+struct __btrfs_workqueue {
 	struct workqueue_struct *normal_wq;
 	/* List head pointing to ordered work list */
 	struct list_head ordered_list;
@@ -49,15 +49,15 @@ struct __btrfs_workqueue_struct {
 	spinlock_t thres_lock;
 };
 
-struct btrfs_workqueue_struct {
-	struct __btrfs_workqueue_struct *normal;
-	struct __btrfs_workqueue_struct *high;
+struct btrfs_workqueue {
+	struct __btrfs_workqueue *normal;
+	struct __btrfs_workqueue *high;
 };
 
-static inline struct __btrfs_workqueue_struct
+static inline struct __btrfs_workqueue
 *__btrfs_alloc_workqueue(char *name, int flags, int max_active, int thresh)
 {
-	struct __btrfs_workqueue_struct *ret = kzalloc(sizeof(*ret), GFP_NOFS);
+	struct __btrfs_workqueue *ret = kzalloc(sizeof(*ret), GFP_NOFS);
 
 	if (unlikely(!ret))
 		return NULL;
@@ -95,14 +95,14 @@ static inline struct __btrfs_workqueue_struct
 }
 
 static inline void
-__btrfs_destroy_workqueue(struct __btrfs_workqueue_struct *wq);
+__btrfs_destroy_workqueue(struct __btrfs_workqueue *wq);
 
-struct btrfs_workqueue_struct *btrfs_alloc_workqueue(char *name,
-						     int flags,
-						     int max_active,
-						     int thresh)
+struct btrfs_workqueue *btrfs_alloc_workqueue(char *name,
+					      int flags,
+					      int max_active,
+					      int thresh)
 {
-	struct btrfs_workqueue_struct *ret = kzalloc(sizeof(*ret), GFP_NOFS);
+	struct btrfs_workqueue *ret = kzalloc(sizeof(*ret), GFP_NOFS);
 
 	if (unlikely(!ret))
 		return NULL;
@@ -131,7 +131,7 @@ struct btrfs_workqueue_struct *btrfs_alloc_workqueue(char *name,
  * This hook WILL be called in IRQ handler context,
  * so workqueue_set_max_active MUST NOT be called in this hook
  */
-static inline void thresh_queue_hook(struct __btrfs_workqueue_struct *wq)
+static inline void thresh_queue_hook(struct __btrfs_workqueue *wq)
 {
 	if (wq->thresh == NO_THRESHOLD)
 		return;
@@ -143,7 +143,7 @@ static inline void thresh_queue_hook(struct __btrfs_workqueue_struct *wq)
  * This hook is called in kthread content.
  * So workqueue_set_max_active is called here.
  */
-static inline void thresh_exec_hook(struct __btrfs_workqueue_struct *wq)
+static inline void thresh_exec_hook(struct __btrfs_workqueue *wq)
 {
 	int new_max_active;
 	long pending;
@@ -186,10 +186,10 @@ out:
 	}
 }
 
-static void run_ordered_work(struct __btrfs_workqueue_struct *wq)
+static void run_ordered_work(struct __btrfs_workqueue *wq)
 {
 	struct list_head *list = &wq->ordered_list;
-	struct btrfs_work_struct *work;
+	struct btrfs_work *work;
 	spinlock_t *lock = &wq->list_lock;
 	unsigned long flags;
 
@@ -197,7 +197,7 @@ static void run_ordered_work(struct __btrfs_workqueue_struct *wq)
 		spin_lock_irqsave(lock, flags);
 		if (list_empty(list))
 			break;
-		work = list_entry(list->next, struct btrfs_work_struct,
+		work = list_entry(list->next, struct btrfs_work,
 				  ordered_list);
 		if (!test_bit(WORK_DONE_BIT, &work->flags))
 			break;
@@ -229,11 +229,11 @@ static void run_ordered_work(struct __btrfs_workqueue_struct *wq)
 
 static void normal_work_helper(struct work_struct *arg)
 {
-	struct btrfs_work_struct *work;
-	struct __btrfs_workqueue_struct *wq;
+	struct btrfs_work *work;
+	struct __btrfs_workqueue *wq;
 	int need_order = 0;
 
-	work = container_of(arg, struct btrfs_work_struct, normal_work);
+	work = container_of(arg, struct btrfs_work, normal_work);
 	/*
 	 * We should not touch things inside work in the following cases:
 	 * 1) after work->func() if it has no ordered_free
@@ -254,10 +254,10 @@ static void normal_work_helper(struct work_struct *arg)
 	}
 }
 
-void btrfs_init_work(struct btrfs_work_struct *work,
-		     void (*func)(struct btrfs_work_struct *),
-		     void (*ordered_func)(struct btrfs_work_struct *),
-		     void (*ordered_free)(struct btrfs_work_struct *))
+void btrfs_init_work(struct btrfs_work *work,
+		     void (*func)(struct btrfs_work *),
+		     void (*ordered_func)(struct btrfs_work *),
+		     void (*ordered_free)(struct btrfs_work *))
 {
 	work->func = func;
 	work->ordered_func = ordered_func;
@@ -267,8 +267,8 @@ void btrfs_init_work(struct btrfs_work_struct *work,
 	work->flags = 0;
 }
 
-static inline void __btrfs_queue_work(struct __btrfs_workqueue_struct *wq,
-				      struct btrfs_work_struct *work)
+static inline void __btrfs_queue_work(struct __btrfs_workqueue *wq,
+				      struct btrfs_work *work)
 {
 	unsigned long flags;
 
@@ -282,10 +282,10 @@ static inline void __btrfs_queue_work(struct __btrfs_workqueue_struct *wq,
 	queue_work(wq->normal_wq, &work->normal_work);
 }
 
-void btrfs_queue_work(struct btrfs_workqueue_struct *wq,
-		      struct btrfs_work_struct *work)
+void btrfs_queue_work(struct btrfs_workqueue *wq,
+		      struct btrfs_work *work)
 {
-	struct __btrfs_workqueue_struct *dest_wq;
+	struct __btrfs_workqueue *dest_wq;
 
 	if (test_bit(WORK_HIGH_PRIO_BIT, &work->flags) && wq->high)
 		dest_wq = wq->high;
@@ -295,13 +295,13 @@ void btrfs_queue_work(struct btrfs_workqueue_struct *wq,
 }
 
 static inline void
-__btrfs_destroy_workqueue(struct __btrfs_workqueue_struct *wq)
+__btrfs_destroy_workqueue(struct __btrfs_workqueue *wq)
 {
 	destroy_workqueue(wq->normal_wq);
 	kfree(wq);
 }
 
-void btrfs_destroy_workqueue(struct btrfs_workqueue_struct *wq)
+void btrfs_destroy_workqueue(struct btrfs_workqueue *wq)
 {
 	if (!wq)
 		return;
@@ -310,14 +310,14 @@ void btrfs_destroy_workqueue(struct btrfs_workqueue_struct *wq)
 	__btrfs_destroy_workqueue(wq->normal);
 }
 
-void btrfs_workqueue_set_max(struct btrfs_workqueue_struct *wq, int max)
+void btrfs_workqueue_set_max(struct btrfs_workqueue *wq, int max)
 {
 	wq->normal->max_active = max;
 	if (wq->high)
 		wq->high->max_active = max;
 }
 
-void btrfs_set_work_high_priority(struct btrfs_work_struct *work)
+void btrfs_set_work_high_priority(struct btrfs_work *work)
 {
 	set_bit(WORK_HIGH_PRIO_BIT, &work->flags);
 }
diff --git a/fs/btrfs/async-thread.h b/fs/btrfs/async-thread.h
index ab05904..08d7174 100644
--- a/fs/btrfs/async-thread.h
+++ b/fs/btrfs/async-thread.h
@@ -20,33 +20,33 @@
 #ifndef __BTRFS_ASYNC_THREAD_
 #define __BTRFS_ASYNC_THREAD_
 
-struct btrfs_workqueue_struct;
+struct btrfs_workqueue;
 /* Internal use only */
-struct __btrfs_workqueue_struct;
+struct __btrfs_workqueue;
 
-struct btrfs_work_struct {
-	void (*func)(struct btrfs_work_struct *arg);
-	void (*ordered_func)(struct btrfs_work_struct *arg);
-	void (*ordered_free)(struct btrfs_work_struct *arg);
+struct btrfs_work {
+	void (*func)(struct btrfs_work *arg);
+	void (*ordered_func)(struct btrfs_work *arg);
+	void (*ordered_free)(struct btrfs_work *arg);
 
 	/* Don't touch things below */
 	struct work_struct normal_work;
 	struct list_head ordered_list;
-	struct __btrfs_workqueue_struct *wq;
+	struct __btrfs_workqueue *wq;
 	unsigned long flags;
 };
 
-struct btrfs_workqueue_struct *btrfs_alloc_workqueue(char *name,
+struct btrfs_workqueue *btrfs_alloc_workqueue(char *name,
 						     int flags,
 						     int max_active,
 						     int thresh);
-void btrfs_init_work(struct btrfs_work_struct *work,
-		     void (*func)(struct btrfs_work_struct *),
-		     void (*ordered_func)(struct btrfs_work_struct *),
-		     void (*ordered_free)(struct btrfs_work_struct *));
-void btrfs_queue_work(struct btrfs_workqueue_struct *wq,
-		      struct btrfs_work_struct *work);
-void btrfs_destroy_workqueue(struct btrfs_workqueue_struct *wq);
-void btrfs_workqueue_set_max(struct btrfs_workqueue_struct *wq, int max);
-void btrfs_set_work_high_priority(struct btrfs_work_struct *work);
+void btrfs_init_work(struct btrfs_work *work,
+		     void (*func)(struct btrfs_work *),
+		     void (*ordered_func)(struct btrfs_work *),
+		     void (*ordered_free)(struct btrfs_work *));
+void btrfs_queue_work(struct btrfs_workqueue *wq,
+		      struct btrfs_work *work);
+void btrfs_destroy_workqueue(struct btrfs_workqueue *wq);
+void btrfs_workqueue_set_max(struct btrfs_workqueue *wq, int max);
+void btrfs_set_work_high_priority(struct btrfs_work *work);
 #endif
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 71bcad0..03f7196 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1221,7 +1221,7 @@ struct btrfs_caching_control {
 	struct list_head list;
 	struct mutex mutex;
 	wait_queue_head_t wait;
-	struct btrfs_work_struct work;
+	struct btrfs_work work;
 	struct btrfs_block_group_cache *block_group;
 	u64 progress;
 	atomic_t count;
@@ -1504,27 +1504,27 @@ struct btrfs_fs_info {
 	 * A third pool does submit_bio to avoid deadlocking with the other
 	 * two
 	 */
-	struct btrfs_workqueue_struct *workers;
-	struct btrfs_workqueue_struct *delalloc_workers;
-	struct btrfs_workqueue_struct *flush_workers;
-	struct btrfs_workqueue_struct *endio_workers;
-	struct btrfs_workqueue_struct *endio_meta_workers;
-	struct btrfs_workqueue_struct *endio_raid56_workers;
-	struct btrfs_workqueue_struct *rmw_workers;
-	struct btrfs_workqueue_struct *endio_meta_write_workers;
-	struct btrfs_workqueue_struct *endio_write_workers;
-	struct btrfs_workqueue_struct *endio_freespace_worker;
-	struct btrfs_workqueue_struct *submit_workers;
-	struct btrfs_workqueue_struct *caching_workers;
-	struct btrfs_workqueue_struct *readahead_workers;
+	struct btrfs_workqueue *workers;
+	struct btrfs_workqueue *delalloc_workers;
+	struct btrfs_workqueue *flush_workers;
+	struct btrfs_workqueue *endio_workers;
+	struct btrfs_workqueue *endio_meta_workers;
+	struct btrfs_workqueue *endio_raid56_workers;
+	struct btrfs_workqueue *rmw_workers;
+	struct btrfs_workqueue *endio_meta_write_workers;
+	struct btrfs_workqueue *endio_write_workers;
+	struct btrfs_workqueue *endio_freespace_worker;
+	struct btrfs_workqueue *submit_workers;
+	struct btrfs_workqueue *caching_workers;
+	struct btrfs_workqueue *readahead_workers;
 
 	/*
 	 * fixup workers take dirty pages that didn't properly go through
 	 * the cow mechanism and make them safe to write.  It happens
 	 * for the sys_munmap function call path
 	 */
-	struct btrfs_workqueue_struct *fixup_workers;
-	struct btrfs_workqueue_struct *delayed_workers;
+	struct btrfs_workqueue *fixup_workers;
+	struct btrfs_workqueue *delayed_workers;
 	struct task_struct *transaction_kthread;
 	struct task_struct *cleaner_kthread;
 	int thread_pool_size;
@@ -1604,9 +1604,9 @@ struct btrfs_fs_info {
 	atomic_t scrub_cancel_req;
 	wait_queue_head_t scrub_pause_wait;
 	int scrub_workers_refcnt;
-	struct btrfs_workqueue_struct *scrub_workers;
-	struct btrfs_workqueue_struct *scrub_wr_completion_workers;
-	struct btrfs_workqueue_struct *scrub_nocow_workers;
+	struct btrfs_workqueue *scrub_workers;
+	struct btrfs_workqueue *scrub_wr_completion_workers;
+	struct btrfs_workqueue *scrub_nocow_workers;
 
 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
 	u32 check_integrity_print_mask;
@@ -1647,9 +1647,9 @@ struct btrfs_fs_info {
 	/* qgroup rescan items */
 	struct mutex qgroup_rescan_lock; /* protects the progress item */
 	struct btrfs_key qgroup_rescan_progress;
-	struct btrfs_workqueue_struct *qgroup_rescan_workers;
+	struct btrfs_workqueue *qgroup_rescan_workers;
 	struct completion qgroup_rescan_completion;
-	struct btrfs_work_struct qgroup_rescan_work;
+	struct btrfs_work qgroup_rescan_work;
 
 	/* filesystem state */
 	unsigned long fs_state;
@@ -3676,7 +3676,7 @@ struct btrfs_delalloc_work {
 	int delay_iput;
 	struct completion completion;
 	struct list_head list;
-	struct btrfs_work_struct work;
+	struct btrfs_work work;
 };
 
 struct btrfs_delalloc_work *btrfs_alloc_delalloc_work(struct inode *inode,
diff --git a/fs/btrfs/delayed-inode.c b/fs/btrfs/delayed-inode.c
index 76e85d6..33e561a 100644
--- a/fs/btrfs/delayed-inode.c
+++ b/fs/btrfs/delayed-inode.c
@@ -1318,10 +1318,10 @@ void btrfs_remove_delayed_node(struct inode *inode)
 struct btrfs_async_delayed_work {
 	struct btrfs_delayed_root *delayed_root;
 	int nr;
-	struct btrfs_work_struct work;
+	struct btrfs_work work;
 };
 
-static void btrfs_async_run_delayed_root(struct btrfs_work_struct *work)
+static void btrfs_async_run_delayed_root(struct btrfs_work *work)
 {
 	struct btrfs_async_delayed_work *async_work;
 	struct btrfs_delayed_root *delayed_root;
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 9225474..63dc934 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -55,7 +55,7 @@
 #endif
 
 static struct extent_io_ops btree_extent_io_ops;
-static void end_workqueue_fn(struct btrfs_work_struct *work);
+static void end_workqueue_fn(struct btrfs_work *work);
 static void free_fs_root(struct btrfs_root *root);
 static int btrfs_check_super_valid(struct btrfs_fs_info *fs_info,
 				    int read_only);
@@ -86,7 +86,7 @@ struct end_io_wq {
 	int error;
 	int metadata;
 	struct list_head list;
-	struct btrfs_work_struct work;
+	struct btrfs_work work;
 };
 
 /*
@@ -108,7 +108,7 @@ struct async_submit_bio {
 	 * can't tell us where in the file the bio should go
 	 */
 	u64 bio_offset;
-	struct btrfs_work_struct work;
+	struct btrfs_work work;
 	int error;
 };
 
@@ -742,7 +742,7 @@ unsigned long btrfs_async_submit_limit(struct btrfs_fs_info *info)
 	return 256 * limit;
 }
 
-static void run_one_async_start(struct btrfs_work_struct *work)
+static void run_one_async_start(struct btrfs_work *work)
 {
 	struct async_submit_bio *async;
 	int ret;
@@ -755,7 +755,7 @@ static void run_one_async_start(struct btrfs_work_struct *work)
 		async->error = ret;
 }
 
-static void run_one_async_done(struct btrfs_work_struct *work)
+static void run_one_async_done(struct btrfs_work *work)
 {
 	struct btrfs_fs_info *fs_info;
 	struct async_submit_bio *async;
@@ -782,7 +782,7 @@ static void run_one_async_done(struct btrfs_work_struct *work)
 			       async->bio_offset);
 }
 
-static void run_one_async_free(struct btrfs_work_struct *work)
+static void run_one_async_free(struct btrfs_work *work)
 {
 	struct async_submit_bio *async;
 
@@ -1664,7 +1664,7 @@ static int setup_bdi(struct btrfs_fs_info *info, struct backing_dev_info *bdi)
  * called by the kthread helper functions to finally call the bio end_io
  * functions.  This is where read checksum verification actually happens
  */
-static void end_workqueue_fn(struct btrfs_work_struct *work)
+static void end_workqueue_fn(struct btrfs_work *work)
 {
 	struct bio *bio;
 	struct end_io_wq *end_io_wq;
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index bb58082..19ea8ad 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -378,7 +378,7 @@ static u64 add_new_free_space(struct btrfs_block_group_cache *block_group,
 	return total_added;
 }
 
-static noinline void caching_thread(struct btrfs_work_struct *work)
+static noinline void caching_thread(struct btrfs_work *work)
 {
 	struct btrfs_block_group_cache *block_group;
 	struct btrfs_fs_info *fs_info;
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 81395d6..f14512b 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -324,7 +324,7 @@ struct async_cow {
 	u64 start;
 	u64 end;
 	struct list_head extents;
-	struct btrfs_work_struct work;
+	struct btrfs_work work;
 };
 
 static noinline int add_async_extent(struct async_cow *cow,
@@ -1000,7 +1000,7 @@ out_unlock:
 /*
  * work queue call back to started compression on a file and pages
  */
-static noinline void async_cow_start(struct btrfs_work_struct *work)
+static noinline void async_cow_start(struct btrfs_work *work)
 {
 	struct async_cow *async_cow;
 	int num_added = 0;
@@ -1018,7 +1018,7 @@ static noinline void async_cow_start(struct btrfs_work_struct *work)
 /*
  * work queue call back to submit previously compressed pages
  */
-static noinline void async_cow_submit(struct btrfs_work_struct *work)
+static noinline void async_cow_submit(struct btrfs_work *work)
 {
 	struct async_cow *async_cow;
 	struct btrfs_root *root;
@@ -1039,7 +1039,7 @@ static noinline void async_cow_submit(struct btrfs_work_struct *work)
 		submit_compressed_extents(async_cow->inode, async_cow);
 }
 
-static noinline void async_cow_free(struct btrfs_work_struct *work)
+static noinline void async_cow_free(struct btrfs_work *work)
 {
 	struct async_cow *async_cow;
 	async_cow = container_of(work, struct async_cow, work);
@@ -1748,10 +1748,10 @@ int btrfs_set_extent_delalloc(struct inode *inode, u64 start, u64 end,
 /* see btrfs_writepage_start_hook for details on why this is required */
 struct btrfs_writepage_fixup {
 	struct page *page;
-	struct btrfs_work_struct work;
+	struct btrfs_work work;
 };
 
-static void btrfs_writepage_fixup_worker(struct btrfs_work_struct *work)
+static void btrfs_writepage_fixup_worker(struct btrfs_work *work)
 {
 	struct btrfs_writepage_fixup *fixup;
 	struct btrfs_ordered_extent *ordered;
@@ -2750,7 +2750,7 @@ out:
 	return ret;
 }
 
-static void finish_ordered_fn(struct btrfs_work_struct *work)
+static void finish_ordered_fn(struct btrfs_work *work)
 {
 	struct btrfs_ordered_extent *ordered_extent;
 	ordered_extent = container_of(work, struct btrfs_ordered_extent, work);
@@ -2763,7 +2763,7 @@ static int btrfs_writepage_end_io_hook(struct page *page, u64 start, u64 end,
 	struct inode *inode = page->mapping->host;
 	struct btrfs_root *root = BTRFS_I(inode)->root;
 	struct btrfs_ordered_extent *ordered_extent = NULL;
-	struct btrfs_workqueue_struct *workers;
+	struct btrfs_workqueue *workers;
 
 	trace_btrfs_writepage_end_io_hook(page, start, end, uptodate);
 
@@ -8370,7 +8370,7 @@ out_notrans:
 	return ret;
 }
 
-static void btrfs_run_delalloc_work(struct btrfs_work_struct *work)
+static void btrfs_run_delalloc_work(struct btrfs_work *work)
 {
 	struct btrfs_delalloc_work *delalloc_work;
 	struct inode *inode;
diff --git a/fs/btrfs/ordered-data.c b/fs/btrfs/ordered-data.c
index 6fa8219..751ee38 100644
--- a/fs/btrfs/ordered-data.c
+++ b/fs/btrfs/ordered-data.c
@@ -576,7 +576,7 @@ void btrfs_remove_ordered_extent(struct inode *inode,
 	wake_up(&entry->wait);
 }
 
-static void btrfs_run_ordered_extent_work(struct btrfs_work_struct *work)
+static void btrfs_run_ordered_extent_work(struct btrfs_work *work)
 {
 	struct btrfs_ordered_extent *ordered;
 
diff --git a/fs/btrfs/ordered-data.h b/fs/btrfs/ordered-data.h
index 84bb236..2468970 100644
--- a/fs/btrfs/ordered-data.h
+++ b/fs/btrfs/ordered-data.h
@@ -130,10 +130,10 @@ struct btrfs_ordered_extent {
 	/* a per root list of all the pending ordered extents */
 	struct list_head root_extent_list;
 
-	struct btrfs_work_struct work;
+	struct btrfs_work work;
 
 	struct completion completion;
-	struct btrfs_work_struct flush_work;
+	struct btrfs_work flush_work;
 	struct list_head work_list;
 };
 
diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
index 38617cc..2cf9058 100644
--- a/fs/btrfs/qgroup.c
+++ b/fs/btrfs/qgroup.c
@@ -1984,7 +1984,7 @@ out:
 	return ret;
 }
 
-static void btrfs_qgroup_rescan_worker(struct btrfs_work_struct *work)
+static void btrfs_qgroup_rescan_worker(struct btrfs_work *work)
 {
 	struct btrfs_fs_info *fs_info = container_of(work, struct btrfs_fs_info,
 						     qgroup_rescan_work);
diff --git a/fs/btrfs/raid56.c b/fs/btrfs/raid56.c
index 5afa564..1269fc3 100644
--- a/fs/btrfs/raid56.c
+++ b/fs/btrfs/raid56.c
@@ -87,7 +87,7 @@ struct btrfs_raid_bio {
 	/*
 	 * for scheduling work in the helper threads
 	 */
-	struct btrfs_work_struct work;
+	struct btrfs_work work;
 
 	/*
 	 * bio list and bio_list_lock are used
@@ -166,8 +166,8 @@ struct btrfs_raid_bio {
 
 static int __raid56_parity_recover(struct btrfs_raid_bio *rbio);
 static noinline void finish_rmw(struct btrfs_raid_bio *rbio);
-static void rmw_work(struct btrfs_work_struct *work);
-static void read_rebuild_work(struct btrfs_work_struct *work);
+static void rmw_work(struct btrfs_work *work);
+static void read_rebuild_work(struct btrfs_work *work);
 static void async_rmw_stripe(struct btrfs_raid_bio *rbio);
 static void async_read_rebuild(struct btrfs_raid_bio *rbio);
 static int fail_bio_stripe(struct btrfs_raid_bio *rbio, struct bio *bio);
@@ -1588,7 +1588,7 @@ struct btrfs_plug_cb {
 	struct blk_plug_cb cb;
 	struct btrfs_fs_info *info;
 	struct list_head rbio_list;
-	struct btrfs_work_struct work;
+	struct btrfs_work work;
 };
 
 /*
@@ -1652,7 +1652,7 @@ static void run_plug(struct btrfs_plug_cb *plug)
  * if the unplug comes from schedule, we have to push the
  * work off to a helper thread
  */
-static void unplug_work(struct btrfs_work_struct *work)
+static void unplug_work(struct btrfs_work *work)
 {
 	struct btrfs_plug_cb *plug;
 	plug = container_of(work, struct btrfs_plug_cb, work);
@@ -2079,7 +2079,7 @@ int raid56_parity_recover(struct btrfs_root *root, struct bio *bio,
 
 }
 
-static void rmw_work(struct btrfs_work_struct *work)
+static void rmw_work(struct btrfs_work *work)
 {
 	struct btrfs_raid_bio *rbio;
 
@@ -2087,7 +2087,7 @@ static void rmw_work(struct btrfs_work_struct *work)
 	raid56_rmw_stripe(rbio);
 }
 
-static void read_rebuild_work(struct btrfs_work_struct *work)
+static void read_rebuild_work(struct btrfs_work *work)
 {
 	struct btrfs_raid_bio *rbio;
 
diff --git a/fs/btrfs/reada.c b/fs/btrfs/reada.c
index 9e01d36..30947f9 100644
--- a/fs/btrfs/reada.c
+++ b/fs/btrfs/reada.c
@@ -91,8 +91,7 @@ struct reada_zone {
 };
 
 struct reada_machine_work {
-	struct btrfs_work_struct
-				work;
+	struct btrfs_work	work;
 	struct btrfs_fs_info	*fs_info;
 };
 
@@ -734,7 +733,7 @@ static int reada_start_machine_dev(struct btrfs_fs_info *fs_info,
 
 }
 
-static void reada_start_machine_worker(struct btrfs_work_struct *work)
+static void reada_start_machine_worker(struct btrfs_work *work)
 {
 	struct reada_machine_work *rmw;
 	struct btrfs_fs_info *fs_info;
diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
index 9223b7b..002e5b8 100644
--- a/fs/btrfs/scrub.c
+++ b/fs/btrfs/scrub.c
@@ -96,8 +96,7 @@ struct scrub_bio {
 #endif
 	int			page_count;
 	int			next_free;
-	struct btrfs_work_struct
-				work;
+	struct btrfs_work	work;
 };
 
 struct scrub_block {
@@ -155,8 +154,7 @@ struct scrub_fixup_nodatasum {
 	struct btrfs_device	*dev;
 	u64			logical;
 	struct btrfs_root	*root;
-	struct btrfs_work_struct
-				work;
+	struct btrfs_work	work;
 	int			mirror_num;
 };
 
@@ -174,8 +172,7 @@ struct scrub_copy_nocow_ctx {
 	int			mirror_num;
 	u64			physical_for_dev_replace;
 	struct list_head	inodes;
-	struct btrfs_work_struct
-				work;
+	struct btrfs_work	work;
 };
 
 struct scrub_warning {
@@ -234,7 +231,7 @@ static int scrub_pages(struct scrub_ctx *sctx, u64 logical, u64 len,
 		       u64 gen, int mirror_num, u8 *csum, int force,
 		       u64 physical_for_dev_replace);
 static void scrub_bio_end_io(struct bio *bio, int err);
-static void scrub_bio_end_io_worker(struct btrfs_work_struct *work);
+static void scrub_bio_end_io_worker(struct btrfs_work *work);
 static void scrub_block_complete(struct scrub_block *sblock);
 static void scrub_remap_extent(struct btrfs_fs_info *fs_info,
 			       u64 extent_logical, u64 extent_len,
@@ -251,14 +248,14 @@ static int scrub_add_page_to_wr_bio(struct scrub_ctx *sctx,
 				    struct scrub_page *spage);
 static void scrub_wr_submit(struct scrub_ctx *sctx);
 static void scrub_wr_bio_end_io(struct bio *bio, int err);
-static void scrub_wr_bio_end_io_worker(struct btrfs_work_struct *work);
+static void scrub_wr_bio_end_io_worker(struct btrfs_work *work);
 static int write_page_nocow(struct scrub_ctx *sctx,
 			    u64 physical_for_dev_replace, struct page *page);
 static int copy_nocow_pages_for_inode(u64 inum, u64 offset, u64 root,
 				      struct scrub_copy_nocow_ctx *ctx);
 static int copy_nocow_pages(struct scrub_ctx *sctx, u64 logical, u64 len,
 			    int mirror_num, u64 physical_for_dev_replace);
-static void copy_nocow_pages_worker(struct btrfs_work_struct *work);
+static void copy_nocow_pages_worker(struct btrfs_work *work);
 static void __scrub_blocked_if_needed(struct btrfs_fs_info *fs_info);
 static void scrub_blocked_if_needed(struct btrfs_fs_info *fs_info);
 
@@ -727,7 +724,7 @@ out:
 	return -EIO;
 }
 
-static void scrub_fixup_nodatasum(struct btrfs_work_struct *work)
+static void scrub_fixup_nodatasum(struct btrfs_work *work)
 {
 	int ret;
 	struct scrub_fixup_nodatasum *fixup;
@@ -1612,7 +1609,7 @@ static void scrub_wr_bio_end_io(struct bio *bio, int err)
 	btrfs_queue_work(fs_info->scrub_wr_completion_workers, &sbio->work);
 }
 
-static void scrub_wr_bio_end_io_worker(struct btrfs_work_struct *work)
+static void scrub_wr_bio_end_io_worker(struct btrfs_work *work)
 {
 	struct scrub_bio *sbio = container_of(work, struct scrub_bio, work);
 	struct scrub_ctx *sctx = sbio->sctx;
@@ -2080,7 +2077,7 @@ static void scrub_bio_end_io(struct bio *bio, int err)
 	btrfs_queue_work(fs_info->scrub_workers, &sbio->work);
 }
 
-static void scrub_bio_end_io_worker(struct btrfs_work_struct *work)
+static void scrub_bio_end_io_worker(struct btrfs_work *work)
 {
 	struct scrub_bio *sbio = container_of(work, struct scrub_bio, work);
 	struct scrub_ctx *sctx = sbio->sctx;
@@ -3138,7 +3135,7 @@ static int record_inode_for_nocow(u64 inum, u64 offset, u64 root, void *ctx)
 
 #define COPY_COMPLETE 1
 
-static void copy_nocow_pages_worker(struct btrfs_work_struct *work)
+static void copy_nocow_pages_worker(struct btrfs_work *work)
 {
 	struct scrub_copy_nocow_ctx *nocow_ctx =
 		container_of(work, struct scrub_copy_nocow_ctx, work);
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 0066cff..b4660c4 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -440,7 +440,7 @@ done:
 	blk_finish_plug(&plug);
 }
 
-static void pending_bios_fn(struct btrfs_work_struct *work)
+static void pending_bios_fn(struct btrfs_work *work)
 {
 	struct btrfs_device *device;
 
diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index 5d9a037..80754f9 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -95,7 +95,7 @@ struct btrfs_device {
 	/* per-device scrub information */
 	struct scrub_ctx *scrub_device;
 
-	struct btrfs_work_struct work;
+	struct btrfs_work work;
 	struct rcu_head rcu;
 	struct work_struct rcu_work;
 
-- 
1.9.0

Re: [PATCH v5 00/18] Replace btrfs_workers with kernel workqueue based btrfs_workqueue

[Filipe David Manana]

On Fri, Feb 28, 2014 at 2:46 AM, Qu Wenruo <quwenruo@cn.fujitsu.com> wrote:
> Add a new btrfs_workqueue_struct which use kernel workqueue to implement
> most of the original btrfs_workers, to replace btrfs_workers.
>
> With this patchset, redundant workqueue codes are replaced with kernel
> workqueue infrastructure, which not only reduces the code size but also the
> effort to maintain it.
>
> The result(somewhat outdated though) from sysbench shows minor improvement on the following server:
> CPU: two-way Xeon X5660
> RAM: 4G
> HDD: SAS HDD, 150G total, 100G partition for btrfs test
>
> Test result on default mount option:
> https://docs.google.com/spreadsheet/ccc?key=0AhpkL3ehzX3pdENjajJTWFg5d1BWbExnYWFpMTJxeUE&usp=sharing
>
> Test result on "-o compress" mount option:
> https://docs.google.com/spreadsheet/ccc?key=0AhpkL3ehzX3pdHdTTEJ6OW96SXJFaDR5enB1SzMzc0E&usp=sharing
>
> Changelog:
> v1->v2:
>   - Fix some workqueue flags.
> v2->v3:
>   - Add the thresholding mechanism to simulate the old behavior
>   - Convert all the btrfs_workers to btrfs_workrqueue_struct.
>   - Fix some potential deadlock when executed in IRQ handler.
> v3->v4:
>   - Change the ordered workqueue implement to fix the performance drop in 32K
>     multi thread random write.
>   - Change the high priority workqueue implement to get an independent high
>     workqueue without starving problem.
>   - Simplify the btrfs_alloc_workqueue parameters.
>   - Coding style cleanup.
>   - Remove the redundant "_struct" suffix.
> v4->v5:
>   - Fix a multithread free-and-use bug reported by Josef and David.
>
> Qu Wenruo (18):
>   btrfs: Cleanup the unused struct async_sched.
>   btrfs: Added btrfs_workqueue_struct implemented ordered execution
>     based on kernel workqueue
>   btrfs: Add high priority workqueue support for btrfs_workqueue_struct
>   btrfs: Add threshold workqueue based on kernel workqueue
>   btrfs: Replace fs_info->workers with btrfs_workqueue.
>   btrfs: Replace fs_info->delalloc_workers with btrfs_workqueue
>   btrfs: Replace fs_info->submit_workers with btrfs_workqueue.
>   btrfs: Replace fs_info->flush_workers with btrfs_workqueue.
>   btrfs: Replace fs_info->endio_* workqueue with btrfs_workqueue.
>   btrfs: Replace fs_info->rmw_workers workqueue with btrfs_workqueue.
>   btrfs: Replace fs_info->cache_workers workqueue with btrfs_workqueue.
>   btrfs: Replace fs_info->readahead_workers workqueue with
>     btrfs_workqueue.
>   btrfs: Replace fs_info->fixup_workers workqueue with btrfs_workqueue.
>   btrfs: Replace fs_info->delayed_workers workqueue with
>     btrfs_workqueue.
>   btrfs: Replace fs_info->qgroup_rescan_worker workqueue with
>     btrfs_workqueue.
>   btrfs: Replace fs_info->scrub_* workqueue with btrfs_workqueue.
>   btrfs: Cleanup the old btrfs_worker.
>   btrfs: Cleanup the "_struct" suffix in btrfs_workequeue
>
>  fs/btrfs/async-thread.c  | 830 ++++++++++++-----------------------------------
>  fs/btrfs/async-thread.h  | 119 ++-----
>  fs/btrfs/ctree.h         |  39 ++-
>  fs/btrfs/delayed-inode.c |   6 +-
>  fs/btrfs/disk-io.c       | 212 +++++-------
>  fs/btrfs/extent-tree.c   |   4 +-
>  fs/btrfs/inode.c         |  38 +--
>  fs/btrfs/ordered-data.c  |  11 +-
>  fs/btrfs/qgroup.c        |  15 +-
>  fs/btrfs/raid56.c        |  21 +-
>  fs/btrfs/reada.c         |   4 +-
>  fs/btrfs/scrub.c         |  70 ++--
>  fs/btrfs/super.c         |  36 +-
>  fs/btrfs/volumes.c       |  16 +-
>  14 files changed, 446 insertions(+), 975 deletions(-)
>
> --
> 1.9.0

Hi Qu,

On latest btrfs-next/master, which includes these patches, kmemleak is
reporting many leaks that seems related to the work queues.
I can reliably reproduce it by running the xfstests.

Dmesg:

[ 1308.359146] kmemleak: 1308 new suspected memory leaks (see
/sys/kernel/debug/kmemleak)

Sample of kmemleak stack traces:

unreferenced object 0xffff8800d3f84408 (size 16):
comm "mount", pid 4214, jiffies 4294927007 (age 1198.824s)
hex dump (first 16 bytes):
30 4c 6b d4 00 88 ff ff 78 5e 6b d4 00 88 ff ff 0Lk.....x^k.....
backtrace:
[<ffffffff816e5b46>] kmemleak_alloc+0x26/0x50
[<ffffffff8118ec1d>] kmem_cache_alloc_trace+0x11d/0x1e0
[<ffffffffa029ce84>] btrfs_alloc_workqueue+0x44/0x2a0 [btrfs]
[<ffffffffa026ac15>] open_ctree+0xff5/0x20a0 [btrfs]
[<ffffffffa0240eac>] btrfs_mount+0x6ec/0x8d0 [btrfs]
[<ffffffff811a4d53>] mount_fs+0x43/0x1b0
[<ffffffff811c2403>] vfs_kern_mount+0x73/0x160
[<ffffffff811c4d49>] do_mount+0x259/0xb70
[<ffffffff811c594e>] SyS_mount+0x8e/0xe0
[<ffffffff81703212>] system_call_fastpath+0x16/0x1b
[<ffffffffffffffff>] 0xffffffffffffffff
unreferenced object 0xffff8800d3f85830 (size 16):
comm "mount", pid 4214, jiffies 4294927008 (age 1198.820s)
hex dump (first 16 bytes):
58 16 0f f5 01 88 ff ff 00 00 00 00 00 00 00 00 X...............
backtrace:
[<ffffffff816e5b46>] kmemleak_alloc+0x26/0x50
[<ffffffff8118ec1d>] kmem_cache_alloc_trace+0x11d/0x1e0
[<ffffffffa029ce84>] btrfs_alloc_workqueue+0x44/0x2a0 [btrfs]
[<ffffffffa026ac35>] open_ctree+0x1015/0x20a0 [btrfs]
[<ffffffffa0240eac>] btrfs_mount+0x6ec/0x8d0 [btrfs]
[<ffffffff811a4d53>] mount_fs+0x43/0x1b0
[<ffffffff811c2403>] vfs_kern_mount+0x73/0x160
[<ffffffff811c4d49>] do_mount+0x259/0xb70
[<ffffffff811c594e>] SyS_mount+0x8e/0xe0
[<ffffffff81703212>] system_call_fastpath+0x16/0x1b
[<ffffffffffffffff>] 0xffffffffffffffff
unreferenced object 0xffff8800d3f84560 (size 16):
comm "mount", pid 4214, jiffies 4294927008 (age 1198.820s)
hex dump (first 16 bytes):
00 40 93 fc 01 88 ff ff 00 00 00 00 00 00 00 00 .@..............
backtrace:
[<ffffffff816e5b46>] kmemleak_alloc+0x26/0x50
[<ffffffff8118ec1d>] kmem_cache_alloc_trace+0x11d/0x1e0
[<ffffffffa029ce84>] btrfs_alloc_workqueue+0x44/0x2a0 [btrfs]
[<ffffffffa026ac52>] open_ctree+0x1032/0x20a0 [btrfs]
[<ffffffffa0240eac>] btrfs_mount+0x6ec/0x8d0 [btrfs]
[<ffffffff811a4d53>] mount_fs+0x43/0x1b0
[<ffffffff811c2403>] vfs_kern_mount+0x73/0x160
[<ffffffff811c4d49>] do_mount+0x259/0xb70
[<ffffffff811c594e>] SyS_mount+0x8e/0xe0
[<ffffffff81703212>] system_call_fastpath+0x16/0x1b
[<ffffffffffffffff>] 0xffffffffffffffff
unreferenced object 0xffff8800d3f856d8 (size 16):
comm "mount", pid 4214, jiffies 4294927008 (age 1198.820s)
hex dump (first 16 bytes):
f0 7c 93 fc 01 88 ff ff 00 00 00 00 00 00 00 00 .|..............
backtrace:
[<ffffffff816e5b46>] kmemleak_alloc+0x26/0x50
[<ffffffff8118ec1d>] kmem_cache_alloc_trace+0x11d/0x1e0
[<ffffffffa029ce84>] btrfs_alloc_workqueue+0x44/0x2a0 [btrfs]
[<ffffffffa026ac6f>] open_ctree+0x104f/0x20a0 [btrfs]
[<ffffffffa0240eac>] btrfs_mount+0x6ec/0x8d0 [btrfs]
[<ffffffff811a4d53>] mount_fs+0x43/0x1b0
[<ffffffff811c2403>] vfs_kern_mount+0x73/0x160
[<ffffffff811c4d49>] do_mount+0x259/0xb70
[<ffffffff811c594e>] SyS_mount+0x8e/0xe0
[<ffffffff81703212>] system_call_fastpath+0x16/0x1b
[<ffffffffffffffff>] 0xffffffffffffffff
unreferenced object 0xffff8800d3f846b8 (size 16):

(....)

Can you confirm if it's related to any of these changes or something else?
Thanks.

>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html



-- 
Filipe David Manana,

"Reasonable men adapt themselves to the world.
 Unreasonable men adapt the world to themselves.
 That's why all progress depends on unreasonable men."

Re: [PATCH v5 04/18] btrfs: Add threshold workqueue based on kernel workqueue

[Alex Lyakas]

Hi Qu,


On Fri, Feb 28, 2014 at 4:46 AM, Qu Wenruo <quwenruo@cn.fujitsu.com> wrote:
> The original btrfs_workers has thresholding functions to dynamically
> create or destroy kthreads.
>
> Though there is no such function in kernel workqueue because the worker
> is not created manually, we can still use the workqueue_set_max_active
> to simulated the behavior, mainly to achieve a better HDD performance by
> setting a high threshold on submit_workers.
> (Sadly, no resource can be saved)
>
> So in this patch, extra workqueue pending counters are introduced to
> dynamically change the max active of each btrfs_workqueue_struct, hoping
> to restore the behavior of the original thresholding function.
>
> Also, workqueue_set_max_active use a mutex to protect workqueue_struct,
> which is not meant to be called too frequently, so a new interval
> mechanism is applied, that will only call workqueue_set_max_active after
> a count of work is queued. Hoping to balance both the random and
> sequence performance on HDD.
>
> Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
> Tested-by: David Sterba <dsterba@suse.cz>
> ---
> Changelog:
> v2->v3:
>   - Add thresholding mechanism to simulate the old thresholding mechanism.
>   - Will not enable thresholding when thresh is set to small value.
> v3->v4:
>   None
> v4->v5:
>   None
> ---
>  fs/btrfs/async-thread.c | 107 ++++++++++++++++++++++++++++++++++++++++++++----
>  fs/btrfs/async-thread.h |   3 +-
>  2 files changed, 101 insertions(+), 9 deletions(-)
>
> diff --git a/fs/btrfs/async-thread.c b/fs/btrfs/async-thread.c
> index 193c849..977bce2 100644
> --- a/fs/btrfs/async-thread.c
> +++ b/fs/btrfs/async-thread.c
> @@ -30,6 +30,9 @@
>  #define WORK_ORDER_DONE_BIT 2
>  #define WORK_HIGH_PRIO_BIT 3
>
> +#define NO_THRESHOLD (-1)
> +#define DFT_THRESHOLD (32)
> +
>  /*
>   * container for the kthread task pointer and the list of pending work
>   * One of these is allocated per thread.
> @@ -737,6 +740,14 @@ struct __btrfs_workqueue_struct {
>
>         /* Spinlock for ordered_list */
>         spinlock_t list_lock;
> +
> +       /* Thresholding related variants */
> +       atomic_t pending;
> +       int max_active;
> +       int current_max;
> +       int thresh;
> +       unsigned int count;
> +       spinlock_t thres_lock;
>  };
>
>  struct btrfs_workqueue_struct {
> @@ -745,19 +756,34 @@ struct btrfs_workqueue_struct {
>  };
>
>  static inline struct __btrfs_workqueue_struct
> -*__btrfs_alloc_workqueue(char *name, int flags, int max_active)
> +*__btrfs_alloc_workqueue(char *name, int flags, int max_active, int thresh)
>  {
>         struct __btrfs_workqueue_struct *ret = kzalloc(sizeof(*ret), GFP_NOFS);
>
>         if (unlikely(!ret))
>                 return NULL;
>
> +       ret->max_active = max_active;
> +       atomic_set(&ret->pending, 0);
> +       if (thresh == 0)
> +               thresh = DFT_THRESHOLD;
> +       /* For low threshold, disabling threshold is a better choice */
> +       if (thresh < DFT_THRESHOLD) {
> +               ret->current_max = max_active;
> +               ret->thresh = NO_THRESHOLD;
> +       } else {
> +               ret->current_max = 1;
> +               ret->thresh = thresh;
> +       }
> +
>         if (flags & WQ_HIGHPRI)
>                 ret->normal_wq = alloc_workqueue("%s-%s-high", flags,
> -                                                max_active, "btrfs", name);
> +                                                ret->max_active,
> +                                                "btrfs", name);
>         else
>                 ret->normal_wq = alloc_workqueue("%s-%s", flags,
> -                                                max_active, "btrfs", name);
> +                                                ret->max_active, "btrfs",
> +                                                name);
Shouldn't we use ret->current_max instead of ret->max_active (in both calls)?
According to the rest of the code, "max_active" is the absolute
maximum beyond which the "normal_wq" cannot go (you use clamp_value to
ensure that). And "current_max" is the current value of "max_active"
of the "normal_wq". But here, you set the "normal_wq" to "max_active"
immediately. Is this intentional?


>         if (unlikely(!ret->normal_wq)) {
>                 kfree(ret);
>                 return NULL;
> @@ -765,6 +791,7 @@ static inline struct __btrfs_workqueue_struct
>
>         INIT_LIST_HEAD(&ret->ordered_list);
>         spin_lock_init(&ret->list_lock);
> +       spin_lock_init(&ret->thres_lock);
>         return ret;
>  }
>
> @@ -773,7 +800,8 @@ __btrfs_destroy_workqueue(struct __btrfs_workqueue_struct *wq);
>
>  struct btrfs_workqueue_struct *btrfs_alloc_workqueue(char *name,
>                                                      int flags,
> -                                                    int max_active)
> +                                                    int max_active,
> +                                                    int thresh)
>  {
>         struct btrfs_workqueue_struct *ret = kzalloc(sizeof(*ret), GFP_NOFS);
>
> @@ -781,14 +809,15 @@ struct btrfs_workqueue_struct *btrfs_alloc_workqueue(char *name,
>                 return NULL;
>
>         ret->normal = __btrfs_alloc_workqueue(name, flags & ~WQ_HIGHPRI,
> -                                             max_active);
> +                                             max_active, thresh);
>         if (unlikely(!ret->normal)) {
>                 kfree(ret);
>                 return NULL;
>         }
>
>         if (flags & WQ_HIGHPRI) {
> -               ret->high = __btrfs_alloc_workqueue(name, flags, max_active);
> +               ret->high = __btrfs_alloc_workqueue(name, flags, max_active,
> +                                                   thresh);
>                 if (unlikely(!ret->high)) {
>                         __btrfs_destroy_workqueue(ret->normal);
>                         kfree(ret);
> @@ -798,6 +827,66 @@ struct btrfs_workqueue_struct *btrfs_alloc_workqueue(char *name,
>         return ret;
>  }
>
> +/*
> + * Hook for threshold which will be called in btrfs_queue_work.
> + * This hook WILL be called in IRQ handler context,
> + * so workqueue_set_max_active MUST NOT be called in this hook
> + */
> +static inline void thresh_queue_hook(struct __btrfs_workqueue_struct *wq)
> +{
> +       if (wq->thresh == NO_THRESHOLD)
> +               return;
> +       atomic_inc(&wq->pending);
> +}
> +
> +/*
> + * Hook for threshold which will be called before executing the work,
> + * This hook is called in kthread content.
> + * So workqueue_set_max_active is called here.
> + */
> +static inline void thresh_exec_hook(struct __btrfs_workqueue_struct *wq)
> +{
> +       int new_max_active;
> +       long pending;
> +       int need_change = 0;
> +
> +       if (wq->thresh == NO_THRESHOLD)
> +               return;
> +
> +       atomic_dec(&wq->pending);
> +       spin_lock(&wq->thres_lock);
> +       /*
> +        * Use wq->count to limit the calling frequency of
> +        * workqueue_set_max_active.
> +        */
> +       wq->count++;
> +       wq->count %= (wq->thresh / 4);
> +       if (!wq->count)
> +               goto  out;
> +       new_max_active = wq->current_max;
> +
> +       /*
> +        * pending may be changed later, but it's OK since we really
> +        * don't need it so accurate to calculate new_max_active.
> +        */
> +       pending = atomic_read(&wq->pending);
> +       if (pending > wq->thresh)
> +               new_max_active++;
> +       if (pending < wq->thresh / 2)
> +               new_max_active--;
> +       new_max_active = clamp_val(new_max_active, 1, wq->max_active);
> +       if (new_max_active != wq->current_max)  {
> +               need_change = 1;
> +               wq->current_max = new_max_active;
> +       }
> +out:
> +       spin_unlock(&wq->thres_lock);
> +
> +       if (need_change) {
> +               workqueue_set_max_active(wq->normal_wq, wq->current_max);
Here you se the "normal_wq" max_active to "current_max", but not when
the normal workqueue has been created initially.
> +       }
> +}
> +
>  static void run_ordered_work(struct __btrfs_workqueue_struct *wq)
>  {
>         struct list_head *list = &wq->ordered_list;
> @@ -858,6 +947,7 @@ static void normal_work_helper(struct work_struct *arg)
>                 need_order = 1;
>         wq = work->wq;
>
> +       thresh_exec_hook(wq);
>         work->func(work);
>         if (need_order) {
>                 set_bit(WORK_DONE_BIT, &work->flags);
> @@ -884,6 +974,7 @@ static inline void __btrfs_queue_work(struct __btrfs_workqueue_struct *wq,
>         unsigned long flags;
>
>         work->wq = wq;
> +       thresh_queue_hook(wq);
>         if (work->ordered_func) {
>                 spin_lock_irqsave(&wq->list_lock, flags);
>                 list_add_tail(&work->ordered_list, &wq->ordered_list);
> @@ -922,9 +1013,9 @@ void btrfs_destroy_workqueue(struct btrfs_workqueue_struct *wq)
>
>  void btrfs_workqueue_set_max(struct btrfs_workqueue_struct *wq, int max)
>  {
> -       workqueue_set_max_active(wq->normal->normal_wq, max);
> +       wq->normal->max_active = max;
>         if (wq->high)
> -               workqueue_set_max_active(wq->high->normal_wq, max);
> +               wq->high->max_active = max;
>  }
>
>  void btrfs_set_work_high_priority(struct btrfs_work_struct *work)
> diff --git a/fs/btrfs/async-thread.h b/fs/btrfs/async-thread.h
> index fce623c..3129d8a 100644
> --- a/fs/btrfs/async-thread.h
> +++ b/fs/btrfs/async-thread.h
> @@ -138,7 +138,8 @@ struct btrfs_work_struct {
>
>  struct btrfs_workqueue_struct *btrfs_alloc_workqueue(char *name,
>                                                      int flags,
> -                                                    int max_active);
> +                                                    int max_active,
> +                                                    int thresh);
>  void btrfs_init_work(struct btrfs_work_struct *work,
>                      void (*func)(struct btrfs_work_struct *),
>                      void (*ordered_func)(struct btrfs_work_struct *),
> --
> 1.9.0
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

Thanks,
Alex.

Re: [PATCH v5 04/18] btrfs: Add threshold workqueue based on kernel workqueue

[Qu Wenruo]

Hi Alex.

Thanks for the review.
Comment inlined below.

Alex Lyakas wrote on 2015/08/19 18:46 +0200:
> Hi Qu,
>
>
> On Fri, Feb 28, 2014 at 4:46 AM, Qu Wenruo <quwenruo@cn.fujitsu.com> wrote:
>> The original btrfs_workers has thresholding functions to dynamically
>> create or destroy kthreads.
>>
>> Though there is no such function in kernel workqueue because the worker
>> is not created manually, we can still use the workqueue_set_max_active
>> to simulated the behavior, mainly to achieve a better HDD performance by
>> setting a high threshold on submit_workers.
>> (Sadly, no resource can be saved)
>>
>> So in this patch, extra workqueue pending counters are introduced to
>> dynamically change the max active of each btrfs_workqueue_struct, hoping
>> to restore the behavior of the original thresholding function.
>>
>> Also, workqueue_set_max_active use a mutex to protect workqueue_struct,
>> which is not meant to be called too frequently, so a new interval
>> mechanism is applied, that will only call workqueue_set_max_active after
>> a count of work is queued. Hoping to balance both the random and
>> sequence performance on HDD.
>>
>> Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
>> Tested-by: David Sterba <dsterba@suse.cz>
>> ---
>> Changelog:
>> v2->v3:
>>    - Add thresholding mechanism to simulate the old thresholding mechanism.
>>    - Will not enable thresholding when thresh is set to small value.
>> v3->v4:
>>    None
>> v4->v5:
>>    None
>> ---
>>   fs/btrfs/async-thread.c | 107 ++++++++++++++++++++++++++++++++++++++++++++----
>>   fs/btrfs/async-thread.h |   3 +-
>>   2 files changed, 101 insertions(+), 9 deletions(-)
>>
>> diff --git a/fs/btrfs/async-thread.c b/fs/btrfs/async-thread.c
>> index 193c849..977bce2 100644
>> --- a/fs/btrfs/async-thread.c
>> +++ b/fs/btrfs/async-thread.c
>> @@ -30,6 +30,9 @@
>>   #define WORK_ORDER_DONE_BIT 2
>>   #define WORK_HIGH_PRIO_BIT 3
>>
>> +#define NO_THRESHOLD (-1)
>> +#define DFT_THRESHOLD (32)
>> +
>>   /*
>>    * container for the kthread task pointer and the list of pending work
>>    * One of these is allocated per thread.
>> @@ -737,6 +740,14 @@ struct __btrfs_workqueue_struct {
>>
>>          /* Spinlock for ordered_list */
>>          spinlock_t list_lock;
>> +
>> +       /* Thresholding related variants */
>> +       atomic_t pending;
>> +       int max_active;
>> +       int current_max;
>> +       int thresh;
>> +       unsigned int count;
>> +       spinlock_t thres_lock;
>>   };
>>
>>   struct btrfs_workqueue_struct {
>> @@ -745,19 +756,34 @@ struct btrfs_workqueue_struct {
>>   };
>>
>>   static inline struct __btrfs_workqueue_struct
>> -*__btrfs_alloc_workqueue(char *name, int flags, int max_active)
>> +*__btrfs_alloc_workqueue(char *name, int flags, int max_active, int thresh)
>>   {
>>          struct __btrfs_workqueue_struct *ret = kzalloc(sizeof(*ret), GFP_NOFS);
>>
>>          if (unlikely(!ret))
>>                  return NULL;
>>
>> +       ret->max_active = max_active;
>> +       atomic_set(&ret->pending, 0);
>> +       if (thresh == 0)
>> +               thresh = DFT_THRESHOLD;
>> +       /* For low threshold, disabling threshold is a better choice */
>> +       if (thresh < DFT_THRESHOLD) {
>> +               ret->current_max = max_active;
>> +               ret->thresh = NO_THRESHOLD;
>> +       } else {
>> +               ret->current_max = 1;
>> +               ret->thresh = thresh;
>> +       }
>> +
>>          if (flags & WQ_HIGHPRI)
>>                  ret->normal_wq = alloc_workqueue("%s-%s-high", flags,
>> -                                                max_active, "btrfs", name);
>> +                                                ret->max_active,
>> +                                                "btrfs", name);
>>          else
>>                  ret->normal_wq = alloc_workqueue("%s-%s", flags,
>> -                                                max_active, "btrfs", name);
>> +                                                ret->max_active, "btrfs",
>> +                                                name);
> Shouldn't we use ret->current_max instead of ret->max_active (in both calls)?
> According to the rest of the code, "max_active" is the absolute
> maximum beyond which the "normal_wq" cannot go (you use clamp_value to
> ensure that). And "current_max" is the current value of "max_active"
> of the "normal_wq". But here, you set the "normal_wq" to "max_active"
> immediately. Is this intentional?
Yes, as you mentioned max_active is the up limit of the concurrency, and 
current_max is the current value of concurrency.

And, yes, it should be ret->current_max.
It doesn't match with previous 'ret->current_max = 1' line, as the 
policy is set max_active to minimal and let it grow if needed, to save 
some resource.

If rec->current_max is also set to max_active, then I may have an excuse 
to say alloc as many workqueues as possible at beginning to improve 
performance.

Nice catch.

Thanks,
Qu
>
>
>>          if (unlikely(!ret->normal_wq)) {
>>                  kfree(ret);
>>                  return NULL;
>> @@ -765,6 +791,7 @@ static inline struct __btrfs_workqueue_struct
>>
>>          INIT_LIST_HEAD(&ret->ordered_list);
>>          spin_lock_init(&ret->list_lock);
>> +       spin_lock_init(&ret->thres_lock);
>>          return ret;
>>   }
>>
>> @@ -773,7 +800,8 @@ __btrfs_destroy_workqueue(struct __btrfs_workqueue_struct *wq);
>>
>>   struct btrfs_workqueue_struct *btrfs_alloc_workqueue(char *name,
>>                                                       int flags,
>> -                                                    int max_active)
>> +                                                    int max_active,
>> +                                                    int thresh)
>>   {
>>          struct btrfs_workqueue_struct *ret = kzalloc(sizeof(*ret), GFP_NOFS);
>>
>> @@ -781,14 +809,15 @@ struct btrfs_workqueue_struct *btrfs_alloc_workqueue(char *name,
>>                  return NULL;
>>
>>          ret->normal = __btrfs_alloc_workqueue(name, flags & ~WQ_HIGHPRI,
>> -                                             max_active);
>> +                                             max_active, thresh);
>>          if (unlikely(!ret->normal)) {
>>                  kfree(ret);
>>                  return NULL;
>>          }
>>
>>          if (flags & WQ_HIGHPRI) {
>> -               ret->high = __btrfs_alloc_workqueue(name, flags, max_active);
>> +               ret->high = __btrfs_alloc_workqueue(name, flags, max_active,
>> +                                                   thresh);
>>                  if (unlikely(!ret->high)) {
>>                          __btrfs_destroy_workqueue(ret->normal);
>>                          kfree(ret);
>> @@ -798,6 +827,66 @@ struct btrfs_workqueue_struct *btrfs_alloc_workqueue(char *name,
>>          return ret;
>>   }
>>
>> +/*
>> + * Hook for threshold which will be called in btrfs_queue_work.
>> + * This hook WILL be called in IRQ handler context,
>> + * so workqueue_set_max_active MUST NOT be called in this hook
>> + */
>> +static inline void thresh_queue_hook(struct __btrfs_workqueue_struct *wq)
>> +{
>> +       if (wq->thresh == NO_THRESHOLD)
>> +               return;
>> +       atomic_inc(&wq->pending);
>> +}
>> +
>> +/*
>> + * Hook for threshold which will be called before executing the work,
>> + * This hook is called in kthread content.
>> + * So workqueue_set_max_active is called here.
>> + */
>> +static inline void thresh_exec_hook(struct __btrfs_workqueue_struct *wq)
>> +{
>> +       int new_max_active;
>> +       long pending;
>> +       int need_change = 0;
>> +
>> +       if (wq->thresh == NO_THRESHOLD)
>> +               return;
>> +
>> +       atomic_dec(&wq->pending);
>> +       spin_lock(&wq->thres_lock);
>> +       /*
>> +        * Use wq->count to limit the calling frequency of
>> +        * workqueue_set_max_active.
>> +        */
>> +       wq->count++;
>> +       wq->count %= (wq->thresh / 4);
>> +       if (!wq->count)
>> +               goto  out;
>> +       new_max_active = wq->current_max;
>> +
>> +       /*
>> +        * pending may be changed later, but it's OK since we really
>> +        * don't need it so accurate to calculate new_max_active.
>> +        */
>> +       pending = atomic_read(&wq->pending);
>> +       if (pending > wq->thresh)
>> +               new_max_active++;
>> +       if (pending < wq->thresh / 2)
>> +               new_max_active--;
>> +       new_max_active = clamp_val(new_max_active, 1, wq->max_active);
>> +       if (new_max_active != wq->current_max)  {
>> +               need_change = 1;
>> +               wq->current_max = new_max_active;
>> +       }
>> +out:
>> +       spin_unlock(&wq->thres_lock);
>> +
>> +       if (need_change) {
>> +               workqueue_set_max_active(wq->normal_wq, wq->current_max);
> Here you se the "normal_wq" max_active to "current_max", but not when
> the normal workqueue has been created initially.
>> +       }
>> +}
>> +
>>   static void run_ordered_work(struct __btrfs_workqueue_struct *wq)
>>   {
>>          struct list_head *list = &wq->ordered_list;
>> @@ -858,6 +947,7 @@ static void normal_work_helper(struct work_struct *arg)
>>                  need_order = 1;
>>          wq = work->wq;
>>
>> +       thresh_exec_hook(wq);
>>          work->func(work);
>>          if (need_order) {
>>                  set_bit(WORK_DONE_BIT, &work->flags);
>> @@ -884,6 +974,7 @@ static inline void __btrfs_queue_work(struct __btrfs_workqueue_struct *wq,
>>          unsigned long flags;
>>
>>          work->wq = wq;
>> +       thresh_queue_hook(wq);
>>          if (work->ordered_func) {
>>                  spin_lock_irqsave(&wq->list_lock, flags);
>>                  list_add_tail(&work->ordered_list, &wq->ordered_list);
>> @@ -922,9 +1013,9 @@ void btrfs_destroy_workqueue(struct btrfs_workqueue_struct *wq)
>>
>>   void btrfs_workqueue_set_max(struct btrfs_workqueue_struct *wq, int max)
>>   {
>> -       workqueue_set_max_active(wq->normal->normal_wq, max);
>> +       wq->normal->max_active = max;
>>          if (wq->high)
>> -               workqueue_set_max_active(wq->high->normal_wq, max);
>> +               wq->high->max_active = max;
>>   }
>>
>>   void btrfs_set_work_high_priority(struct btrfs_work_struct *work)
>> diff --git a/fs/btrfs/async-thread.h b/fs/btrfs/async-thread.h
>> index fce623c..3129d8a 100644
>> --- a/fs/btrfs/async-thread.h
>> +++ b/fs/btrfs/async-thread.h
>> @@ -138,7 +138,8 @@ struct btrfs_work_struct {
>>
>>   struct btrfs_workqueue_struct *btrfs_alloc_workqueue(char *name,
>>                                                       int flags,
>> -                                                    int max_active);
>> +                                                    int max_active,
>> +                                                    int thresh);
>>   void btrfs_init_work(struct btrfs_work_struct *work,
>>                       void (*func)(struct btrfs_work_struct *),
>>                       void (*ordered_func)(struct btrfs_work_struct *),
>> --
>> 1.9.0
>>
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>
> Thanks,
> Alex.
>