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From: Mel Gorman on 28 Jul 2010 06:30
From: Mostly Christoph Hellwig <hch(a)lst.de>

This is a roll-up of patches in linux-next that Wu's patches depend on. They
are included here for convenience of testing against mainline. They should
be unnecessary for testing against mmotm.

No signoff-required.
---
fs/btrfs/inode.c | 2 +-
fs/drop_caches.c | 2 +-
fs/fs-writeback.c | 90 ++++++++++++++++++----
fs/gfs2/inode.c | 2 +-
fs/inode.c | 16 ++--
fs/nilfs2/gcdat.c | 2 +-
fs/notify/inode_mark.c | 6 +-
fs/notify/inotify/inotify.c | 7 +-
fs/quota/dquot.c | 2 +-
fs/xfs/linux-2.6/xfs_iops.c | 4 +-
include/linux/backing-dev.h | 7 +-
include/linux/fs.h | 4 +-
include/trace/events/writeback.h | 155 ++++++++++++++++++++++++++++++++++++++
mm/backing-dev.c | 114 ++++++----------------------
mm/page-writeback.c | 4 +
15 files changed, 284 insertions(+), 133 deletions(-)
create mode 100644 include/trace/events/writeback.h

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 1bff92a..ecf556d 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -3858,7 +3858,7 @@ again:
p = &parent->rb_right;
else {
WARN_ON(!(entry->vfs_inode.i_state &
- (I_WILL_FREE | I_FREEING | I_CLEAR)));
+ (I_WILL_FREE | I_FREEING)));
rb_erase(parent, &root->inode_tree);
RB_CLEAR_NODE(parent);
spin_unlock(&root->inode_lock);
diff --git a/fs/drop_caches.c b/fs/drop_caches.c
index 83c4f60..2195c21 100644
--- a/fs/drop_caches.c
+++ b/fs/drop_caches.c
@@ -18,7 +18,7 @@ static void drop_pagecache_sb(struct super_block *sb, void *unused)

spin_lock(&inode_lock);
list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
- if (inode->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE|I_NEW))
+ if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW))
continue;
if (inode->i_mapping->nrpages == 0)
continue;
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index d5be169..10f939a 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -26,15 +26,9 @@
#include <linux/blkdev.h>
#include <linux/backing-dev.h>
#include <linux/buffer_head.h>
+#include <linux/tracepoint.h>
#include "internal.h"

-#define inode_to_bdi(inode) ((inode)->i_mapping->backing_dev_info)
-
-/*
- * We don't actually have pdflush, but this one is exported though /proc...
- */
-int nr_pdflush_threads;
-
/*
* Passed into wb_writeback(), essentially a subset of writeback_control
*/
@@ -50,6 +44,21 @@ struct wb_writeback_work {
struct completion *done; /* set if the caller waits */
};

+/*
+ * Include the creation of the trace points after defining the
+ * wb_writeback_work structure so that the definition remains local to this
+ * file.
+ */
+#define CREATE_TRACE_POINTS
+#include <trace/events/writeback.h>
+
+#define inode_to_bdi(inode) ((inode)->i_mapping->backing_dev_info)
+
+/*
+ * We don't actually have pdflush, but this one is exported though /proc...
+ */
+int nr_pdflush_threads;
+
/**
* writeback_in_progress - determine whether there is writeback in progress
* @bdi: the device's backing_dev_info structure.
@@ -65,6 +74,8 @@ int writeback_in_progress(struct backing_dev_info *bdi)
static void bdi_queue_work(struct backing_dev_info *bdi,
struct wb_writeback_work *work)
{
+ trace_writeback_queue(bdi, work);
+
spin_lock(&bdi->wb_lock);
list_add_tail(&work->list, &bdi->work_list);
spin_unlock(&bdi->wb_lock);
@@ -73,9 +84,10 @@ static void bdi_queue_work(struct backing_dev_info *bdi,
* If the default thread isn't there, make sure we add it. When
* it gets created and wakes up, we'll run this work.
*/
- if (unlikely(list_empty_careful(&bdi->wb_list)))
+ if (unlikely(!bdi->wb.task)) {
+ trace_writeback_nothread(bdi, work);
wake_up_process(default_backing_dev_info.wb.task);
- else {
+ } else {
struct bdi_writeback *wb = &bdi->wb;

if (wb->task)
@@ -95,8 +107,10 @@ __bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages,
*/
work = kzalloc(sizeof(*work), GFP_ATOMIC);
if (!work) {
- if (bdi->wb.task)
+ if (bdi->wb.task) {
+ trace_writeback_nowork(bdi);
wake_up_process(bdi->wb.task);
+ }
return;
}

@@ -352,7 +366,7 @@ writeback_single_inode(struct inode *inode, struct writeback_control *wbc)

spin_lock(&inode_lock);
inode->i_state &= ~I_SYNC;
- if (!(inode->i_state & (I_FREEING | I_CLEAR))) {
+ if (!(inode->i_state & I_FREEING)) {
if ((inode->i_state & I_DIRTY_PAGES) && wbc->for_kupdate) {
/*
* More pages get dirtied by a fast dirtier.
@@ -499,7 +513,7 @@ static int writeback_sb_inodes(struct super_block *sb, struct bdi_writeback *wb,
if (inode_dirtied_after(inode, wbc->wb_start))
return 1;

- BUG_ON(inode->i_state & (I_FREEING | I_CLEAR));
+ BUG_ON(inode->i_state & I_FREEING);
__iget(inode);
pages_skipped = wbc->pages_skipped;
writeback_single_inode(inode, wbc);
@@ -642,10 +656,14 @@ static long wb_writeback(struct bdi_writeback *wb,
wbc.more_io = 0;
wbc.nr_to_write = MAX_WRITEBACK_PAGES;
wbc.pages_skipped = 0;
+
+ trace_wbc_writeback_start(&wbc, wb->bdi);
if (work->sb)
__writeback_inodes_sb(work->sb, wb, &wbc);
else
writeback_inodes_wb(wb, &wbc);
+ trace_wbc_writeback_written(&wbc, wb->bdi);
+
work->nr_pages -= MAX_WRITEBACK_PAGES - wbc.nr_to_write;
wrote += MAX_WRITEBACK_PAGES - wbc.nr_to_write;

@@ -673,6 +691,7 @@ static long wb_writeback(struct bdi_writeback *wb,
if (!list_empty(&wb->b_more_io)) {
inode = list_entry(wb->b_more_io.prev,
struct inode, i_list);
+ trace_wbc_writeback_wait(&wbc, wb->bdi);
inode_wait_for_writeback(inode);
}
spin_unlock(&inode_lock);
@@ -751,6 +770,8 @@ long wb_do_writeback(struct bdi_writeback *wb, int force_wait)
if (force_wait)
work->sync_mode = WB_SYNC_ALL;

+ trace_writeback_exec(bdi, work);
+
wrote += wb_writeback(wb, work);

/*
@@ -775,15 +796,43 @@ long wb_do_writeback(struct bdi_writeback *wb, int force_wait)
* Handle writeback of dirty data for the device backed by this bdi. Also
* wakes up periodically and does kupdated style flushing.
*/
-int bdi_writeback_task(struct bdi_writeback *wb)
+int bdi_writeback_thread(void *data)
{
+ struct bdi_writeback *wb = data;
+ struct backing_dev_info *bdi = wb->bdi;
unsigned long last_active = jiffies;
unsigned long wait_jiffies = -1UL;
long pages_written;

+ /*
+ * Add us to the active bdi_list
+ */
+ spin_lock_bh(&bdi_lock);
+ list_add_rcu(&bdi->bdi_list, &bdi_list);
+ spin_unlock_bh(&bdi_lock);
+
+ current->flags |= PF_FLUSHER | PF_SWAPWRITE;
+ set_freezable();
+
+ /*
+ * Our parent may run at a different priority, just set us to normal
+ */
+ set_user_nice(current, 0);
+
+ /*
+ * Clear pending bit and wakeup anybody waiting to tear us down
+ */
+ clear_bit(BDI_pending, &bdi->state);
+ smp_mb__after_clear_bit();
+ wake_up_bit(&bdi->state, BDI_pending);
+
+ trace_writeback_thread_start(bdi);
+
while (!kthread_should_stop()) {
pages_written = wb_do_writeback(wb, 0);

+ trace_writeback_pages_written(pages_written);
+
if (pages_written)
last_active = jiffies;
else if (wait_jiffies != -1UL) {
@@ -813,9 +862,20 @@ int bdi_writeback_task(struct bdi_writeback *wb)
try_to_freeze();
}

+ wb->task = NULL;
+
+ /*
+ * Flush any work that raced with us exiting. No new work
+ * will be added, since this bdi isn't discoverable anymore.
+ */
+ if (!list_empty(&bdi->work_list))
+ wb_do_writeback(wb, 1);
+
+ trace_writeback_thread_stop(bdi);
return 0;
}

+
/*
* Start writeback of `nr_pages' pages. If `nr_pages' is zero, write back
* the whole world.
@@ -935,7 +995,7 @@ void __mark_inode_dirty(struct inode *inode, int flags)
if (hlist_unhashed(&inode->i_hash))
goto out;
}
- if (inode->i_state & (I_FREEING|I_CLEAR))
+ if (inode->i_state & I_FREEING)
goto out;

/*
@@ -1001,7 +1061,7 @@ static void wait_sb_inodes(struct super_block *sb)
list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
struct address_space *mapping;

- if (inode->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE|I_NEW))
+ if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW))
continue;
mapping = inode->i_mapping;
if (mapping->nrpages == 0)
diff --git a/fs/gfs2/inode.c b/fs/gfs2/inode.c
index f03afd9..edc30b2 100644
--- a/fs/gfs2/inode.c
+++ b/fs/gfs2/inode.c
@@ -84,7 +84,7 @@ static int iget_skip_test(struct inode *inode, void *opaque)
struct gfs2_skip_data *data = opaque;

if (ip->i_no_addr == data->no_addr) {
- if (inode->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE)){
+ if (inode->i_state & (I_FREEING|I_WILL_FREE)){
data->skipped = 1;
return 0;
}
diff --git a/fs/inode.c b/fs/inode.c
index 722860b..71fe079 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -317,7 +317,7 @@ void clear_inode(struct inode *inode)
bd_forget(inode);
if (S_ISCHR(inode->i_mode) && inode->i_cdev)
cd_forget(inode);
- inode->i_state = I_CLEAR;
+ inode->i_state = I_FREEING | I_CLEAR;
}
EXPORT_SYMBOL(clear_inode);

@@ -553,7 +553,7 @@ repeat:
continue;
if (!test(inode, data))
continue;
- if (inode->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE)) {
+ if (inode->i_state & (I_FREEING|I_WILL_FREE)) {
__wait_on_freeing_inode(inode);
goto repeat;
}
@@ -578,7 +578,7 @@ repeat:
continue;
if (inode->i_sb != sb)
continue;
- if (inode->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE)) {
+ if (inode->i_state & (I_FREEING|I_WILL_FREE)) {
__wait_on_freeing_inode(inode);
goto repeat;
}
@@ -840,7 +840,7 @@ EXPORT_SYMBOL(iunique);
struct inode *igrab(struct inode *inode)
{
spin_lock(&inode_lock);
- if (!(inode->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE)))
+ if (!(inode->i_state & (I_FREEING|I_WILL_FREE)))
__iget(inode);
else
/*
@@ -1089,7 +1089,7 @@ int insert_inode_locked(struct inode *inode)
continue;
if (old->i_sb != sb)
continue;
- if (old->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE))
+ if (old->i_state & (I_FREEING|I_WILL_FREE))
continue;
break;
}
@@ -1128,7 +1128,7 @@ int insert_inode_locked4(struct inode *inode, unsigned long hashval,
continue;
if (!test(old, data))
continue;
- if (old->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE))
+ if (old->i_state & (I_FREEING|I_WILL_FREE))
continue;
break;
}
@@ -1218,7 +1218,7 @@ void generic_delete_inode(struct inode *inode)
hlist_del_init(&inode->i_hash);
spin_unlock(&inode_lock);
wake_up_inode(inode);
- BUG_ON(inode->i_state != I_CLEAR);
+ BUG_ON(inode->i_state != (I_FREEING | I_CLEAR));
destroy_inode(inode);
}
EXPORT_SYMBOL(generic_delete_inode);
@@ -1322,7 +1322,7 @@ static inline void iput_final(struct inode *inode)
void iput(struct inode *inode)
{
if (inode) {
- BUG_ON(inode->i_state == I_CLEAR);
+ BUG_ON(inode->i_state & I_CLEAR);

if (atomic_dec_and_lock(&inode->i_count, &inode_lock))
iput_final(inode);
diff --git a/fs/nilfs2/gcdat.c b/fs/nilfs2/gcdat.c
index dd5f7e0..84a45d1 100644
--- a/fs/nilfs2/gcdat.c
+++ b/fs/nilfs2/gcdat.c
@@ -78,7 +78,7 @@ void nilfs_clear_gcdat_inode(struct the_nilfs *nilfs)
struct inode *gcdat = nilfs->ns_gc_dat;
struct nilfs_inode_info *gii = NILFS_I(gcdat);

- gcdat->i_state = I_CLEAR;
+ gcdat->i_state = I_FREEING | I_CLEAR;
gii->i_flags = 0;

nilfs_palloc_clear_cache(gcdat);
diff --git a/fs/notify/inode_mark.c b/fs/notify/inode_mark.c
index 0399bcb..152b83e 100644
--- a/fs/notify/inode_mark.c
+++ b/fs/notify/inode_mark.c
@@ -369,11 +369,11 @@ void fsnotify_unmount_inodes(struct list_head *list)
struct inode *need_iput_tmp;

/*
- * We cannot __iget() an inode in state I_CLEAR, I_FREEING,
+ * We cannot __iget() an inode in state I_FREEING,
* I_WILL_FREE, or I_NEW which is fine because by that point
* the inode cannot have any associated watches.
*/
- if (inode->i_state & (I_CLEAR|I_FREEING|I_WILL_FREE|I_NEW))
+ if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW))
continue;

/*
@@ -397,7 +397,7 @@ void fsnotify_unmount_inodes(struct list_head *list)
/* In case the dropping of a reference would nuke next_i. */
if ((&next_i->i_sb_list != list) &&
atomic_read(&next_i->i_count) &&
- !(next_i->i_state & (I_CLEAR | I_FREEING | I_WILL_FREE))) {
+ !(next_i->i_state & (I_FREEING | I_WILL_FREE))) {
__iget(next_i);
need_iput = next_i;
}
diff --git a/fs/notify/inotify/inotify.c b/fs/notify/inotify/inotify.c
index 27b75eb..cf6b042 100644
--- a/fs/notify/inotify/inotify.c
+++ b/fs/notify/inotify/inotify.c
@@ -377,11 +377,11 @@ void inotify_unmount_inodes(struct list_head *list)
struct list_head *watches;

/*
- * We cannot __iget() an inode in state I_CLEAR, I_FREEING,
+ * We cannot __iget() an inode in state I_FREEING,
* I_WILL_FREE, or I_NEW which is fine because by that point
* the inode cannot have any associated watches.
*/
- if (inode->i_state & (I_CLEAR|I_FREEING|I_WILL_FREE|I_NEW))
+ if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW))
continue;

/*
@@ -403,8 +403,7 @@ void inotify_unmount_inodes(struct list_head *list)
/* In case the dropping of a reference would nuke next_i. */
if ((&next_i->i_sb_list != list) &&
atomic_read(&next_i->i_count) &&
- !(next_i->i_state & (I_CLEAR | I_FREEING |
- I_WILL_FREE))) {
+ !(next_i->i_state & (I_FREEING|I_WILL_FREE))) {
__iget(next_i);
need_iput = next_i;
}
diff --git a/fs/quota/dquot.c b/fs/quota/dquot.c
index 437d2ca..5cec3e2 100644
--- a/fs/quota/dquot.c
+++ b/fs/quota/dquot.c
@@ -885,7 +885,7 @@ static void add_dquot_ref(struct super_block *sb, int type)

spin_lock(&inode_lock);
list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
- if (inode->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE|I_NEW))
+ if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW))
continue;
#ifdef CONFIG_QUOTA_DEBUG
if (unlikely(inode_get_rsv_space(inode) > 0))
diff --git a/fs/xfs/linux-2.6/xfs_iops.c b/fs/xfs/linux-2.6/xfs_iops.c
index 44f0b2d..f4f0a41 100644
--- a/fs/xfs/linux-2.6/xfs_iops.c
+++ b/fs/xfs/linux-2.6/xfs_iops.c
@@ -88,7 +88,7 @@ xfs_mark_inode_dirty_sync(
{
struct inode *inode = VFS_I(ip);

- if (!(inode->i_state & (I_WILL_FREE|I_FREEING|I_CLEAR)))
+ if (!(inode->i_state & (I_WILL_FREE|I_FREEING)))
mark_inode_dirty_sync(inode);
}

@@ -98,7 +98,7 @@ xfs_mark_inode_dirty(
{
struct inode *inode = VFS_I(ip);

- if (!(inode->i_state & (I_WILL_FREE|I_FREEING|I_CLEAR)))
+ if (!(inode->i_state & (I_WILL_FREE|I_FREEING)))
mark_inode_dirty(inode);
}

diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h
index e9aec0d..e536f3a 100644
--- a/include/linux/backing-dev.h
+++ b/include/linux/backing-dev.h
@@ -45,8 +45,6 @@ enum bdi_stat_item {
#define BDI_STAT_BATCH (8*(1+ilog2(nr_cpu_ids)))

struct bdi_writeback {
- struct list_head list; /* hangs off the bdi */
-
struct backing_dev_info *bdi; /* our parent bdi */
unsigned int nr;

@@ -80,8 +78,7 @@ struct backing_dev_info {
unsigned int max_ratio, max_prop_frac;

struct bdi_writeback wb; /* default writeback info for this bdi */
- spinlock_t wb_lock; /* protects update side of wb_list */
- struct list_head wb_list; /* the flusher threads hanging off this bdi */
+ spinlock_t wb_lock; /* protects work_list */

struct list_head work_list;

@@ -105,7 +102,7 @@ void bdi_unregister(struct backing_dev_info *bdi);
int bdi_setup_and_register(struct backing_dev_info *, char *, unsigned int);
void bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages);
void bdi_start_background_writeback(struct backing_dev_info *bdi);
-int bdi_writeback_task(struct bdi_writeback *wb);
+int bdi_writeback_thread(void *data);
int bdi_has_dirty_io(struct backing_dev_info *bdi);
void bdi_arm_supers_timer(void);

diff --git a/include/linux/fs.h b/include/linux/fs.h
index 68ca1b0..e29f0ed 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1615,8 +1615,8 @@ struct super_operations {
* I_FREEING Set when inode is about to be freed but still has dirty
* pages or buffers attached or the inode itself is still
* dirty.
- * I_CLEAR Set by clear_inode(). In this state the inode is clean
- * and can be destroyed.
+ * I_CLEAR Added by clear_inode(). In this state the inode is clean
+ * and can be destroyed. Inode keeps I_FREEING.
*
* Inodes that are I_WILL_FREE, I_FREEING or I_CLEAR are
* prohibited for many purposes. iget() must wait for
diff --git a/include/trace/events/writeback.h b/include/trace/events/writeback.h
new file mode 100644
index 0000000..0be26ac
--- /dev/null
+++ b/include/trace/events/writeback.h
@@ -0,0 +1,155 @@
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM writeback
+
+#if !defined(_TRACE_WRITEBACK_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_WRITEBACK_H
+
+#include <linux/backing-dev.h>
+#include <linux/writeback.h>
+
+struct wb_writeback_work;
+
+DECLARE_EVENT_CLASS(writeback_work_class,
+ TP_PROTO(struct backing_dev_info *bdi, struct wb_writeback_work *work),
+ TP_ARGS(bdi, work),
+ TP_STRUCT__entry(
+ __array(char, name, 32)
+ __field(long, nr_pages)
+ __field(dev_t, sb_dev)
+ __field(int, sync_mode)
+ __field(int, for_kupdate)
+ __field(int, range_cyclic)
+ __field(int, for_background)
+ ),
+ TP_fast_assign(
+ strncpy(__entry->name, dev_name(bdi->dev), 32);
+ __entry->nr_pages = work->nr_pages;
+ __entry->sb_dev = work->sb ? work->sb->s_dev : 0;
+ __entry->sync_mode = work->sync_mode;
+ __entry->for_kupdate = work->for_kupdate;
+ __entry->range_cyclic = work->range_cyclic;
+ __entry->for_background = work->for_background;
+ ),
+ TP_printk("bdi %s: sb_dev %d:%d nr_pages=%ld sync_mode=%d "
+ "kupdate=%d range_cyclic=%d background=%d",
+ __entry->name,
+ MAJOR(__entry->sb_dev), MINOR(__entry->sb_dev),
+ __entry->nr_pages,
+ __entry->sync_mode,
+ __entry->for_kupdate,
+ __entry->range_cyclic,
+ __entry->for_background
+ )
+);
+#define DEFINE_WRITEBACK_WORK_EVENT(name) \
+DEFINE_EVENT(writeback_work_class, name, \
+ TP_PROTO(struct backing_dev_info *bdi, struct wb_writeback_work *work), \
+ TP_ARGS(bdi, work))
+DEFINE_WRITEBACK_WORK_EVENT(writeback_nothread);
+DEFINE_WRITEBACK_WORK_EVENT(writeback_queue);
+DEFINE_WRITEBACK_WORK_EVENT(writeback_exec);
+
+TRACE_EVENT(writeback_pages_written,
+ TP_PROTO(long pages_written),
+ TP_ARGS(pages_written),
+ TP_STRUCT__entry(
+ __field(long, pages)
+ ),
+ TP_fast_assign(
+ __entry->pages = pages_written;
+ ),
+ TP_printk("%ld", __entry->pages)
+);
+
+DECLARE_EVENT_CLASS(writeback_class,
+ TP_PROTO(struct backing_dev_info *bdi),
+ TP_ARGS(bdi),
+ TP_STRUCT__entry(
+ __array(char, name, 32)
+ ),
+ TP_fast_assign(
+ strncpy(__entry->name, dev_name(bdi->dev), 32);
+ ),
+ TP_printk("bdi %s",
+ __entry->name
+ )
+);
+#define DEFINE_WRITEBACK_EVENT(name) \
+DEFINE_EVENT(writeback_class, name, \
+ TP_PROTO(struct backing_dev_info *bdi), \
+ TP_ARGS(bdi))
+
+DEFINE_WRITEBACK_EVENT(writeback_nowork);
+DEFINE_WRITEBACK_EVENT(writeback_bdi_register);
+DEFINE_WRITEBACK_EVENT(writeback_bdi_unregister);
+DEFINE_WRITEBACK_EVENT(writeback_thread_start);
+DEFINE_WRITEBACK_EVENT(writeback_thread_stop);
+
+DECLARE_EVENT_CLASS(wbc_class,
+ TP_PROTO(struct writeback_control *wbc, struct backing_dev_info *bdi),
+ TP_ARGS(wbc, bdi),
+ TP_STRUCT__entry(
+ __array(char, name, 32)
+ __field(long, nr_to_write)
+ __field(long, pages_skipped)
+ __field(int, sync_mode)
+ __field(int, nonblocking)
+ __field(int, encountered_congestion)
+ __field(int, for_kupdate)
+ __field(int, for_background)
+ __field(int, for_reclaim)
+ __field(int, range_cyclic)
+ __field(int, more_io)
+ __field(unsigned long, older_than_this)
+ __field(long, range_start)
+ __field(long, range_end)
+ ),
+
+ TP_fast_assign(
+ strncpy(__entry->name, dev_name(bdi->dev), 32);
+ __entry->nr_to_write = wbc->nr_to_write;
+ __entry->pages_skipped = wbc->pages_skipped;
+ __entry->sync_mode = wbc->sync_mode;
+ __entry->for_kupdate = wbc->for_kupdate;
+ __entry->for_background = wbc->for_background;
+ __entry->for_reclaim = wbc->for_reclaim;
+ __entry->range_cyclic = wbc->range_cyclic;
+ __entry->more_io = wbc->more_io;
+ __entry->older_than_this = wbc->older_than_this ?
+ *wbc->older_than_this : 0;
+ __entry->range_start = (long)wbc->range_start;
+ __entry->range_end = (long)wbc->range_end;
+ ),
+
+ TP_printk("bdi %s: towrt=%ld skip=%ld mode=%d kupd=%d "
+ "bgrd=%d reclm=%d cyclic=%d more=%d older=0x%lx "
+ "start=0x%lx end=0x%lx",
+ __entry->name,
+ __entry->nr_to_write,
+ __entry->pages_skipped,
+ __entry->sync_mode,
+ __entry->for_kupdate,
+ __entry->for_background,
+ __entry->for_reclaim,
+ __entry->range_cyclic,
+ __entry->more_io,
+ __entry->older_than_this,
+ __entry->range_start,
+ __entry->range_end)
+)
+
+#define DEFINE_WBC_EVENT(name) \
+DEFINE_EVENT(wbc_class, name, \
+ TP_PROTO(struct writeback_control *wbc, struct backing_dev_info *bdi), \
+ TP_ARGS(wbc, bdi))
+DEFINE_WBC_EVENT(wbc_writeback_start);
+DEFINE_WBC_EVENT(wbc_writeback_written);
+DEFINE_WBC_EVENT(wbc_writeback_wait);
+DEFINE_WBC_EVENT(wbc_balance_dirty_start);
+DEFINE_WBC_EVENT(wbc_balance_dirty_written);
+DEFINE_WBC_EVENT(wbc_balance_dirty_wait);
+
+#endif /* _TRACE_WRITEBACK_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>
diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index 123bcef..ac78a33 100644
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -10,6 +10,7 @@
#include <linux/module.h>
#include <linux/writeback.h>
#include <linux/device.h>
+#include <trace/events/writeback.h>

static atomic_long_t bdi_seq = ATOMIC_LONG_INIT(0);

@@ -65,28 +66,21 @@ static void bdi_debug_init(void)
static int bdi_debug_stats_show(struct seq_file *m, void *v)
{
struct backing_dev_info *bdi = m->private;
- struct bdi_writeback *wb;
+ struct bdi_writeback *wb = &bdi->wb;
unsigned long background_thresh;
unsigned long dirty_thresh;
unsigned long bdi_thresh;
unsigned long nr_dirty, nr_io, nr_more_io, nr_wb;
struct inode *inode;

- /*
- * inode lock is enough here, the bdi->wb_list is protected by
- * RCU on the reader side
- */
nr_wb = nr_dirty = nr_io = nr_more_io = 0;
spin_lock(&inode_lock);
- list_for_each_entry(wb, &bdi->wb_list, list) {
- nr_wb++;
- list_for_each_entry(inode, &wb->b_dirty, i_list)
- nr_dirty++;
- list_for_each_entry(inode, &wb->b_io, i_list)
- nr_io++;
- list_for_each_entry(inode, &wb->b_more_io, i_list)
- nr_more_io++;
- }
+ list_for_each_entry(inode, &wb->b_dirty, i_list)
+ nr_dirty++;
+ list_for_each_entry(inode, &wb->b_io, i_list)
+ nr_io++;
+ list_for_each_entry(inode, &wb->b_more_io, i_list)
+ nr_more_io++;
spin_unlock(&inode_lock);

get_dirty_limits(&background_thresh, &dirty_thresh, &bdi_thresh, bdi);
@@ -98,19 +92,16 @@ static int bdi_debug_stats_show(struct seq_file *m, void *v)
"BdiDirtyThresh: %8lu kB\n"
"DirtyThresh: %8lu kB\n"
"BackgroundThresh: %8lu kB\n"
- "WritebackThreads: %8lu\n"
"b_dirty: %8lu\n"
"b_io: %8lu\n"
"b_more_io: %8lu\n"
"bdi_list: %8u\n"
- "state: %8lx\n"
- "wb_list: %8u\n",
+ "state: %8lx\n",
(unsigned long) K(bdi_stat(bdi, BDI_WRITEBACK)),
(unsigned long) K(bdi_stat(bdi, BDI_RECLAIMABLE)),
K(bdi_thresh), K(dirty_thresh),
- K(background_thresh), nr_wb, nr_dirty, nr_io, nr_more_io,
- !list_empty(&bdi->bdi_list), bdi->state,
- !list_empty(&bdi->wb_list));
+ K(background_thresh), nr_dirty, nr_io, nr_more_io,
+ !list_empty(&bdi->bdi_list), bdi->state);
#undef K

return 0;
@@ -270,66 +261,6 @@ static void bdi_wb_init(struct bdi_writeback *wb, struct backing_dev_info *bdi)
INIT_LIST_HEAD(&wb->b_more_io);
}

-static void bdi_task_init(struct backing_dev_info *bdi,
- struct bdi_writeback *wb)
-{
- struct task_struct *tsk = current;
-
- spin_lock(&bdi->wb_lock);
- list_add_tail_rcu(&wb->list, &bdi->wb_list);
- spin_unlock(&bdi->wb_lock);
-
- tsk->flags |= PF_FLUSHER | PF_SWAPWRITE;
- set_freezable();
-
- /*
- * Our parent may run at a different priority, just set us to normal
- */
- set_user_nice(tsk, 0);
-}
-
-static int bdi_start_fn(void *ptr)
-{
- struct bdi_writeback *wb = ptr;
- struct backing_dev_info *bdi = wb->bdi;
- int ret;
-
- /*
- * Add us to the active bdi_list
- */
- spin_lock_bh(&bdi_lock);
- list_add_rcu(&bdi->bdi_list, &bdi_list);
- spin_unlock_bh(&bdi_lock);
-
- bdi_task_init(bdi, wb);
-
- /*
- * Clear pending bit and wakeup anybody waiting to tear us down
- */
- clear_bit(BDI_pending, &bdi->state);
- smp_mb__after_clear_bit();
- wake_up_bit(&bdi->state, BDI_pending);
-
- ret = bdi_writeback_task(wb);
-
- /*
- * Remove us from the list
- */
- spin_lock(&bdi->wb_lock);
- list_del_rcu(&wb->list);
- spin_unlock(&bdi->wb_lock);
-
- /*
- * Flush any work that raced with us exiting. No new work
- * will be added, since this bdi isn't discoverable anymore.
- */
- if (!list_empty(&bdi->work_list))
- wb_do_writeback(wb, 1);
-
- wb->task = NULL;
- return ret;
-}
-
int bdi_has_dirty_io(struct backing_dev_info *bdi)
{
return wb_has_dirty_io(&bdi->wb);
@@ -391,7 +322,13 @@ static int bdi_forker_task(void *ptr)
{
struct bdi_writeback *me = ptr;

- bdi_task_init(me->bdi, me);
+ current->flags |= PF_FLUSHER | PF_SWAPWRITE;
+ set_freezable();
+
+ /*
+ * Our parent may run at a different priority, just set us to normal
+ */
+ set_user_nice(current, 0);

for (;;) {
struct backing_dev_info *bdi, *tmp;
@@ -447,7 +384,7 @@ static int bdi_forker_task(void *ptr)
spin_unlock_bh(&bdi_lock);

wb = &bdi->wb;
- wb->task = kthread_run(bdi_start_fn, wb, "flush-%s",
+ wb->task = kthread_run(bdi_writeback_thread, wb, "flush-%s",
dev_name(bdi->dev));
/*
* If task creation fails, then readd the bdi to
@@ -582,6 +519,7 @@ int bdi_register(struct backing_dev_info *bdi, struct device *parent,

bdi_debug_register(bdi, dev_name(dev));
set_bit(BDI_registered, &bdi->state);
+ trace_writeback_bdi_register(bdi);
exit:
return ret;
}
@@ -598,8 +536,6 @@ EXPORT_SYMBOL(bdi_register_dev);
*/
static void bdi_wb_shutdown(struct backing_dev_info *bdi)
{
- struct bdi_writeback *wb;
-
if (!bdi_cap_writeback_dirty(bdi))
return;

@@ -615,14 +551,14 @@ static void bdi_wb_shutdown(struct backing_dev_info *bdi)
bdi_remove_from_list(bdi);

/*
- * Finally, kill the kernel threads. We don't need to be RCU
+ * Finally, kill the kernel thread. We don't need to be RCU
* safe anymore, since the bdi is gone from visibility. Force
* unfreeze of the thread before calling kthread_stop(), otherwise
* it would never exet if it is currently stuck in the refrigerator.
*/
- list_for_each_entry(wb, &bdi->wb_list, list) {
- thaw_process(wb->task);
- kthread_stop(wb->task);
+ if (bdi->wb.task) {
+ thaw_process(bdi->wb.task);
+ kthread_stop(bdi->wb.task);
}
}

@@ -644,6 +580,7 @@ static void bdi_prune_sb(struct backing_dev_info *bdi)
void bdi_unregister(struct backing_dev_info *bdi)
{
if (bdi->dev) {
+ trace_writeback_bdi_unregister(bdi);
bdi_prune_sb(bdi);

if (!bdi_cap_flush_forker(bdi))
@@ -667,7 +604,6 @@ int bdi_init(struct backing_dev_info *bdi)
spin_lock_init(&bdi->wb_lock);
INIT_RCU_HEAD(&bdi->rcu_head);
INIT_LIST_HEAD(&bdi->bdi_list);
- INIT_LIST_HEAD(&bdi->wb_list);
INIT_LIST_HEAD(&bdi->work_list);

bdi_wb_init(&bdi->wb, bdi);
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 37498ef..d556cd8 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -34,6 +34,7 @@
#include <linux/syscalls.h>
#include <linux/buffer_head.h>
#include <linux/pagevec.h>
+#include <trace/events/writeback.h>

/*
* After a CPU has dirtied this many pages, balance_dirty_pages_ratelimited
@@ -535,11 +536,13 @@ static void balance_dirty_pages(struct address_space *mapping,
* threshold otherwise wait until the disk writes catch
* up.
*/
+ trace_wbc_balance_dirty_start(&wbc, bdi);
if (bdi_nr_reclaimable > bdi_thresh) {
writeback_inodes_wb(&bdi->wb, &wbc);
pages_written += write_chunk - wbc.nr_to_write;
get_dirty_limits(&background_thresh, &dirty_thresh,
&bdi_thresh, bdi);
+ trace_wbc_balance_dirty_written(&wbc, bdi);
}

/*
@@ -565,6 +568,7 @@ static void balance_dirty_pages(struct address_space *mapping,
if (pages_written >= write_chunk)
break; /* We've done our duty */

+ trace_wbc_balance_dirty_wait(&wbc, bdi);
__set_current_state(TASK_INTERRUPTIBLE);
io_schedule_timeout(pause);

--
1.7.1

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