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Merge branch 'writeback-for-linus' of git://git.kernel.org/pub/scm/li…
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…nux/kernel/git/wfg/linux

* 'writeback-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/wfg/linux:
  writeback: Add a 'reason' to wb_writeback_work
  writeback: send work item to queue_io, move_expired_inodes
  writeback: trace event balance_dirty_pages
  writeback: trace event bdi_dirty_ratelimit
  writeback: fix ppc compile warnings on do_div(long long, unsigned long)
  writeback: per-bdi background threshold
  writeback: dirty position control - bdi reserve area
  writeback: control dirty pause time
  writeback: limit max dirty pause time
  writeback: IO-less balance_dirty_pages()
  writeback: per task dirty rate limit
  writeback: stabilize bdi->dirty_ratelimit
  writeback: dirty rate control
  writeback: add bg_threshold parameter to __bdi_update_bandwidth()
  writeback: dirty position control
  writeback: account per-bdi accumulated dirtied pages
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torvalds committed Nov 7, 2011
2 parents 6aad373 + 0e175a1 commit 208bca0
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Showing 15 changed files with 806 additions and 225 deletions.
3 changes: 2 additions & 1 deletion fs/btrfs/extent-tree.c
Original file line number Diff line number Diff line change
Expand Up @@ -3340,7 +3340,8 @@ static int shrink_delalloc(struct btrfs_trans_handle *trans,
smp_mb();
nr_pages = min_t(unsigned long, nr_pages,
root->fs_info->delalloc_bytes >> PAGE_CACHE_SHIFT);
writeback_inodes_sb_nr_if_idle(root->fs_info->sb, nr_pages);
writeback_inodes_sb_nr_if_idle(root->fs_info->sb, nr_pages,
WB_REASON_FS_FREE_SPACE);

spin_lock(&space_info->lock);
if (reserved > space_info->bytes_reserved)
Expand Down
2 changes: 1 addition & 1 deletion fs/buffer.c
Original file line number Diff line number Diff line change
Expand Up @@ -288,7 +288,7 @@ static void free_more_memory(void)
struct zone *zone;
int nid;

wakeup_flusher_threads(1024);
wakeup_flusher_threads(1024, WB_REASON_FREE_MORE_MEM);
yield();

for_each_online_node(nid) {
Expand Down
2 changes: 1 addition & 1 deletion fs/ext4/inode.c
Original file line number Diff line number Diff line change
Expand Up @@ -2372,7 +2372,7 @@ static int ext4_nonda_switch(struct super_block *sb)
* start pushing delalloc when 1/2 of free blocks are dirty.
*/
if (free_blocks < 2 * dirty_blocks)
writeback_inodes_sb_if_idle(sb);
writeback_inodes_sb_if_idle(sb, WB_REASON_FS_FREE_SPACE);

return 0;
}
Expand Down
84 changes: 57 additions & 27 deletions fs/fs-writeback.c
Original file line number Diff line number Diff line change
Expand Up @@ -41,11 +41,23 @@ struct wb_writeback_work {
unsigned int for_kupdate:1;
unsigned int range_cyclic:1;
unsigned int for_background:1;
enum wb_reason reason; /* why was writeback initiated? */

struct list_head list; /* pending work list */
struct completion *done; /* set if the caller waits */
};

const char *wb_reason_name[] = {
[WB_REASON_BACKGROUND] = "background",
[WB_REASON_TRY_TO_FREE_PAGES] = "try_to_free_pages",
[WB_REASON_SYNC] = "sync",
[WB_REASON_PERIODIC] = "periodic",
[WB_REASON_LAPTOP_TIMER] = "laptop_timer",
[WB_REASON_FREE_MORE_MEM] = "free_more_memory",
[WB_REASON_FS_FREE_SPACE] = "fs_free_space",
[WB_REASON_FORKER_THREAD] = "forker_thread"
};

/*
* Include the creation of the trace points after defining the
* wb_writeback_work structure so that the definition remains local to this
Expand Down Expand Up @@ -115,7 +127,7 @@ static void bdi_queue_work(struct backing_dev_info *bdi,

static void
__bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages,
bool range_cyclic)
bool range_cyclic, enum wb_reason reason)
{
struct wb_writeback_work *work;

Expand All @@ -135,6 +147,7 @@ __bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages,
work->sync_mode = WB_SYNC_NONE;
work->nr_pages = nr_pages;
work->range_cyclic = range_cyclic;
work->reason = reason;

bdi_queue_work(bdi, work);
}
Expand All @@ -150,9 +163,10 @@ __bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages,
* completion. Caller need not hold sb s_umount semaphore.
*
*/
void bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages)
void bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages,
enum wb_reason reason)
{
__bdi_start_writeback(bdi, nr_pages, true);
__bdi_start_writeback(bdi, nr_pages, true, reason);
}

/**
Expand Down Expand Up @@ -251,7 +265,7 @@ static bool inode_dirtied_after(struct inode *inode, unsigned long t)
*/
static int move_expired_inodes(struct list_head *delaying_queue,
struct list_head *dispatch_queue,
unsigned long *older_than_this)
struct wb_writeback_work *work)
{
LIST_HEAD(tmp);
struct list_head *pos, *node;
Expand All @@ -262,8 +276,8 @@ static int move_expired_inodes(struct list_head *delaying_queue,

while (!list_empty(delaying_queue)) {
inode = wb_inode(delaying_queue->prev);
if (older_than_this &&
inode_dirtied_after(inode, *older_than_this))
if (work->older_than_this &&
inode_dirtied_after(inode, *work->older_than_this))
break;
if (sb && sb != inode->i_sb)
do_sb_sort = 1;
Expand Down Expand Up @@ -302,13 +316,13 @@ static int move_expired_inodes(struct list_head *delaying_queue,
* |
* +--> dequeue for IO
*/
static void queue_io(struct bdi_writeback *wb, unsigned long *older_than_this)
static void queue_io(struct bdi_writeback *wb, struct wb_writeback_work *work)
{
int moved;
assert_spin_locked(&wb->list_lock);
list_splice_init(&wb->b_more_io, &wb->b_io);
moved = move_expired_inodes(&wb->b_dirty, &wb->b_io, older_than_this);
trace_writeback_queue_io(wb, older_than_this, moved);
moved = move_expired_inodes(&wb->b_dirty, &wb->b_io, work);
trace_writeback_queue_io(wb, work, moved);
}

static int write_inode(struct inode *inode, struct writeback_control *wbc)
Expand Down Expand Up @@ -641,31 +655,40 @@ static long __writeback_inodes_wb(struct bdi_writeback *wb,
return wrote;
}

long writeback_inodes_wb(struct bdi_writeback *wb, long nr_pages)
long writeback_inodes_wb(struct bdi_writeback *wb, long nr_pages,
enum wb_reason reason)
{
struct wb_writeback_work work = {
.nr_pages = nr_pages,
.sync_mode = WB_SYNC_NONE,
.range_cyclic = 1,
.reason = reason,
};

spin_lock(&wb->list_lock);
if (list_empty(&wb->b_io))
queue_io(wb, NULL);
queue_io(wb, &work);
__writeback_inodes_wb(wb, &work);
spin_unlock(&wb->list_lock);

return nr_pages - work.nr_pages;
}

static inline bool over_bground_thresh(void)
static bool over_bground_thresh(struct backing_dev_info *bdi)
{
unsigned long background_thresh, dirty_thresh;

global_dirty_limits(&background_thresh, &dirty_thresh);

return (global_page_state(NR_FILE_DIRTY) +
global_page_state(NR_UNSTABLE_NFS) > background_thresh);
if (global_page_state(NR_FILE_DIRTY) +
global_page_state(NR_UNSTABLE_NFS) > background_thresh)
return true;

if (bdi_stat(bdi, BDI_RECLAIMABLE) >
bdi_dirty_limit(bdi, background_thresh))
return true;

return false;
}

/*
Expand All @@ -675,7 +698,7 @@ static inline bool over_bground_thresh(void)
static void wb_update_bandwidth(struct bdi_writeback *wb,
unsigned long start_time)
{
__bdi_update_bandwidth(wb->bdi, 0, 0, 0, 0, start_time);
__bdi_update_bandwidth(wb->bdi, 0, 0, 0, 0, 0, start_time);
}

/*
Expand Down Expand Up @@ -727,7 +750,7 @@ static long wb_writeback(struct bdi_writeback *wb,
* For background writeout, stop when we are below the
* background dirty threshold
*/
if (work->for_background && !over_bground_thresh())
if (work->for_background && !over_bground_thresh(wb->bdi))
break;

if (work->for_kupdate) {
Expand All @@ -738,7 +761,7 @@ static long wb_writeback(struct bdi_writeback *wb,

trace_writeback_start(wb->bdi, work);
if (list_empty(&wb->b_io))
queue_io(wb, work->older_than_this);
queue_io(wb, work);
if (work->sb)
progress = writeback_sb_inodes(work->sb, wb, work);
else
Expand Down Expand Up @@ -811,13 +834,14 @@ static unsigned long get_nr_dirty_pages(void)

static long wb_check_background_flush(struct bdi_writeback *wb)
{
if (over_bground_thresh()) {
if (over_bground_thresh(wb->bdi)) {

struct wb_writeback_work work = {
.nr_pages = LONG_MAX,
.sync_mode = WB_SYNC_NONE,
.for_background = 1,
.range_cyclic = 1,
.reason = WB_REASON_BACKGROUND,
};

return wb_writeback(wb, &work);
Expand Down Expand Up @@ -851,6 +875,7 @@ static long wb_check_old_data_flush(struct bdi_writeback *wb)
.sync_mode = WB_SYNC_NONE,
.for_kupdate = 1,
.range_cyclic = 1,
.reason = WB_REASON_PERIODIC,
};

return wb_writeback(wb, &work);
Expand Down Expand Up @@ -969,7 +994,7 @@ int bdi_writeback_thread(void *data)
* Start writeback of `nr_pages' pages. If `nr_pages' is zero, write back
* the whole world.
*/
void wakeup_flusher_threads(long nr_pages)
void wakeup_flusher_threads(long nr_pages, enum wb_reason reason)
{
struct backing_dev_info *bdi;

Expand All @@ -982,7 +1007,7 @@ void wakeup_flusher_threads(long nr_pages)
list_for_each_entry_rcu(bdi, &bdi_list, bdi_list) {
if (!bdi_has_dirty_io(bdi))
continue;
__bdi_start_writeback(bdi, nr_pages, false);
__bdi_start_writeback(bdi, nr_pages, false, reason);
}
rcu_read_unlock();
}
Expand Down Expand Up @@ -1203,7 +1228,9 @@ static void wait_sb_inodes(struct super_block *sb)
* on how many (if any) will be written, and this function does not wait
* for IO completion of submitted IO.
*/
void writeback_inodes_sb_nr(struct super_block *sb, unsigned long nr)
void writeback_inodes_sb_nr(struct super_block *sb,
unsigned long nr,
enum wb_reason reason)
{
DECLARE_COMPLETION_ONSTACK(done);
struct wb_writeback_work work = {
Expand All @@ -1212,6 +1239,7 @@ void writeback_inodes_sb_nr(struct super_block *sb, unsigned long nr)
.tagged_writepages = 1,
.done = &done,
.nr_pages = nr,
.reason = reason,
};

WARN_ON(!rwsem_is_locked(&sb->s_umount));
Expand All @@ -1228,9 +1256,9 @@ EXPORT_SYMBOL(writeback_inodes_sb_nr);
* on how many (if any) will be written, and this function does not wait
* for IO completion of submitted IO.
*/
void writeback_inodes_sb(struct super_block *sb)
void writeback_inodes_sb(struct super_block *sb, enum wb_reason reason)
{
return writeback_inodes_sb_nr(sb, get_nr_dirty_pages());
return writeback_inodes_sb_nr(sb, get_nr_dirty_pages(), reason);
}
EXPORT_SYMBOL(writeback_inodes_sb);

Expand All @@ -1241,11 +1269,11 @@ EXPORT_SYMBOL(writeback_inodes_sb);
* Invoke writeback_inodes_sb if no writeback is currently underway.
* Returns 1 if writeback was started, 0 if not.
*/
int writeback_inodes_sb_if_idle(struct super_block *sb)
int writeback_inodes_sb_if_idle(struct super_block *sb, enum wb_reason reason)
{
if (!writeback_in_progress(sb->s_bdi)) {
down_read(&sb->s_umount);
writeback_inodes_sb(sb);
writeback_inodes_sb(sb, reason);
up_read(&sb->s_umount);
return 1;
} else
Expand All @@ -1262,11 +1290,12 @@ EXPORT_SYMBOL(writeback_inodes_sb_if_idle);
* Returns 1 if writeback was started, 0 if not.
*/
int writeback_inodes_sb_nr_if_idle(struct super_block *sb,
unsigned long nr)
unsigned long nr,
enum wb_reason reason)
{
if (!writeback_in_progress(sb->s_bdi)) {
down_read(&sb->s_umount);
writeback_inodes_sb_nr(sb, nr);
writeback_inodes_sb_nr(sb, nr, reason);
up_read(&sb->s_umount);
return 1;
} else
Expand All @@ -1290,6 +1319,7 @@ void sync_inodes_sb(struct super_block *sb)
.nr_pages = LONG_MAX,
.range_cyclic = 0,
.done = &done,
.reason = WB_REASON_SYNC,
};

WARN_ON(!rwsem_is_locked(&sb->s_umount));
Expand Down
2 changes: 1 addition & 1 deletion fs/quota/quota.c
Original file line number Diff line number Diff line change
Expand Up @@ -286,7 +286,7 @@ static int do_quotactl(struct super_block *sb, int type, int cmd, qid_t id,
/* caller already holds s_umount */
if (sb->s_flags & MS_RDONLY)
return -EROFS;
writeback_inodes_sb(sb);
writeback_inodes_sb(sb, WB_REASON_SYNC);
return 0;
default:
return -EINVAL;
Expand Down
4 changes: 2 additions & 2 deletions fs/sync.c
Original file line number Diff line number Diff line change
Expand Up @@ -43,7 +43,7 @@ static int __sync_filesystem(struct super_block *sb, int wait)
if (wait)
sync_inodes_sb(sb);
else
writeback_inodes_sb(sb);
writeback_inodes_sb(sb, WB_REASON_SYNC);

if (sb->s_op->sync_fs)
sb->s_op->sync_fs(sb, wait);
Expand Down Expand Up @@ -98,7 +98,7 @@ static void sync_filesystems(int wait)
*/
SYSCALL_DEFINE0(sync)
{
wakeup_flusher_threads(0);
wakeup_flusher_threads(0, WB_REASON_SYNC);
sync_filesystems(0);
sync_filesystems(1);
if (unlikely(laptop_mode))
Expand Down
2 changes: 1 addition & 1 deletion fs/ubifs/budget.c
Original file line number Diff line number Diff line change
Expand Up @@ -63,7 +63,7 @@
static void shrink_liability(struct ubifs_info *c, int nr_to_write)
{
down_read(&c->vfs_sb->s_umount);
writeback_inodes_sb(c->vfs_sb);
writeback_inodes_sb(c->vfs_sb, WB_REASON_FS_FREE_SPACE);
up_read(&c->vfs_sb->s_umount);
}

Expand Down
14 changes: 13 additions & 1 deletion include/linux/backing-dev.h
Original file line number Diff line number Diff line change
Expand Up @@ -40,6 +40,7 @@ typedef int (congested_fn)(void *, int);
enum bdi_stat_item {
BDI_RECLAIMABLE,
BDI_WRITEBACK,
BDI_DIRTIED,
BDI_WRITTEN,
NR_BDI_STAT_ITEMS
};
Expand Down Expand Up @@ -74,10 +75,20 @@ struct backing_dev_info {
struct percpu_counter bdi_stat[NR_BDI_STAT_ITEMS];

unsigned long bw_time_stamp; /* last time write bw is updated */
unsigned long dirtied_stamp;
unsigned long written_stamp; /* pages written at bw_time_stamp */
unsigned long write_bandwidth; /* the estimated write bandwidth */
unsigned long avg_write_bandwidth; /* further smoothed write bw */

/*
* The base dirty throttle rate, re-calculated on every 200ms.
* All the bdi tasks' dirty rate will be curbed under it.
* @dirty_ratelimit tracks the estimated @balanced_dirty_ratelimit
* in small steps and is much more smooth/stable than the latter.
*/
unsigned long dirty_ratelimit;
unsigned long balanced_dirty_ratelimit;

struct prop_local_percpu completions;
int dirty_exceeded;

Expand Down Expand Up @@ -107,7 +118,8 @@ int bdi_register(struct backing_dev_info *bdi, struct device *parent,
int bdi_register_dev(struct backing_dev_info *bdi, dev_t dev);
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_writeback(struct backing_dev_info *bdi, long nr_pages,
enum wb_reason reason);
void bdi_start_background_writeback(struct backing_dev_info *bdi);
int bdi_writeback_thread(void *data);
int bdi_has_dirty_io(struct backing_dev_info *bdi);
Expand Down
7 changes: 7 additions & 0 deletions include/linux/sched.h
Original file line number Diff line number Diff line change
Expand Up @@ -1522,6 +1522,13 @@ struct task_struct {
int make_it_fail;
#endif
struct prop_local_single dirties;
/*
* when (nr_dirtied >= nr_dirtied_pause), it's time to call
* balance_dirty_pages() for some dirty throttling pause
*/
int nr_dirtied;
int nr_dirtied_pause;

#ifdef CONFIG_LATENCYTOP
int latency_record_count;
struct latency_record latency_record[LT_SAVECOUNT];
Expand Down
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