#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 writeback_in_progress(struct backing_dev_info *bdi)
{
- return !list_empty(&bdi->work_list);
+ return test_bit(BDI_writeback_running, &bdi->state);
+}
+
+static inline struct backing_dev_info *inode_to_bdi(struct inode *inode)
+{
+ struct super_block *sb = inode->i_sb;
+
+ if (strcmp(sb->s_type->name, "bdev") == 0)
+ return inode->i_mapping->backing_dev_info;
+
+ return sb->s_bdi;
}
static void bdi_queue_work(struct backing_dev_info *bdi,
{
trace_writeback_queue(bdi, work);
- spin_lock(&bdi->wb_lock);
+ spin_lock_bh(&bdi->wb_lock);
list_add_tail(&work->list, &bdi->work_list);
- spin_unlock(&bdi->wb_lock);
-
- /*
- * 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(!bdi->wb.task)) {
+ if (bdi->wb.task) {
+ wake_up_process(bdi->wb.task);
+ } else {
+ /*
+ * The bdi thread isn't there, wake up the forker thread which
+ * will create and run it.
+ */
trace_writeback_nothread(bdi, work);
wake_up_process(default_backing_dev_info.wb.task);
- } else {
- struct bdi_writeback *wb = &bdi->wb;
-
- if (wb->task)
- wake_up_process(wb->task);
}
+ spin_unlock_bh(&bdi->wb_lock);
}
static void
/*
* Queue all expired dirty inodes for io, eldest first.
+ * Before
+ * newly dirtied b_dirty b_io b_more_io
+ * =============> gf edc BA
+ * After
+ * newly dirtied b_dirty b_io b_more_io
+ * =============> g fBAedc
+ * |
+ * +--> dequeue for IO
*/
static void queue_io(struct bdi_writeback *wb, unsigned long *older_than_this)
{
- list_splice_init(&wb->b_more_io, wb->b_io.prev);
+ list_splice_init(&wb->b_more_io, &wb->b_io);
move_expired_inodes(&wb->b_dirty, &wb->b_io, older_than_this);
}
spin_lock(&inode_lock);
inode->i_state &= ~I_SYNC;
- if (!(inode->i_state & (I_FREEING | I_CLEAR))) {
- if ((inode->i_state & I_DIRTY_PAGES) && wbc->for_kupdate) {
- /*
- * More pages get dirtied by a fast dirtier.
- */
- goto select_queue;
- } else if (inode->i_state & I_DIRTY) {
- /*
- * At least XFS will redirty the inode during the
- * writeback (delalloc) and on io completion (isize).
- */
- redirty_tail(inode);
- } else if (mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) {
+ if (!(inode->i_state & I_FREEING)) {
+ if (mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) {
/*
* We didn't write back all the pages. nfs_writepages()
- * sometimes bales out without doing anything. Redirty
- * the inode; Move it from b_io onto b_more_io/b_dirty.
+ * sometimes bales out without doing anything.
*/
- /*
- * akpm: if the caller was the kupdate function we put
- * this inode at the head of b_dirty so it gets first
- * consideration. Otherwise, move it to the tail, for
- * the reasons described there. I'm not really sure
- * how much sense this makes. Presumably I had a good
- * reasons for doing it this way, and I'd rather not
- * muck with it at present.
- */
- if (wbc->for_kupdate) {
+ inode->i_state |= I_DIRTY_PAGES;
+ if (wbc->nr_to_write <= 0) {
/*
- * For the kupdate function we move the inode
- * to b_more_io so it will get more writeout as
- * soon as the queue becomes uncongested.
+ * slice used up: queue for next turn
*/
- inode->i_state |= I_DIRTY_PAGES;
-select_queue:
- if (wbc->nr_to_write <= 0) {
- /*
- * slice used up: queue for next turn
- */
- requeue_io(inode);
- } else {
- /*
- * somehow blocked: retry later
- */
- redirty_tail(inode);
- }
+ requeue_io(inode);
} else {
/*
- * Otherwise fully redirty the inode so that
- * other inodes on this superblock will get some
- * writeout. Otherwise heavy writing to one
- * file would indefinitely suspend writeout of
- * all the other files.
+ * Writeback blocked by something other than
+ * congestion. Delay the inode for some time to
+ * avoid spinning on the CPU (100% iowait)
+ * retrying writeback of the dirty page/inode
+ * that cannot be performed immediately.
*/
- inode->i_state |= I_DIRTY_PAGES;
redirty_tail(inode);
}
+ } else if (inode->i_state & I_DIRTY) {
+ /*
+ * Filesystems can dirty the inode during writeback
+ * operations, such as delayed allocation during
+ * submission or metadata updates after data IO
+ * completion.
+ */
+ redirty_tail(inode);
} else if (atomic_read(&inode->i_count)) {
/*
* The inode is clean, inuse
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);
{
int ret = 0;
- wbc->wb_start = jiffies; /* livelock avoidance */
+ if (!wbc->wb_start)
+ wbc->wb_start = jiffies; /* livelock avoidance */
spin_lock(&inode_lock);
if (!wbc->for_kupdate || list_empty(&wb->b_io))
queue_io(wb, wbc->older_than_this);
{
WARN_ON(!rwsem_is_locked(&sb->s_umount));
- wbc->wb_start = jiffies; /* livelock avoidance */
spin_lock(&inode_lock);
if (!wbc->for_kupdate || list_empty(&wb->b_io))
queue_io(wb, wbc->older_than_this);
{
unsigned long background_thresh, dirty_thresh;
- get_dirty_limits(&background_thresh, &dirty_thresh, NULL, NULL);
+ global_dirty_limits(&background_thresh, &dirty_thresh);
return (global_page_state(NR_FILE_DIRTY) +
global_page_state(NR_UNSTABLE_NFS) >= background_thresh);
wbc.range_end = LLONG_MAX;
}
+ wbc.wb_start = jiffies; /* livelock avoidance */
for (;;) {
/*
* Stop writeback when nr_pages has been consumed
{
struct wb_writeback_work *work = NULL;
- spin_lock(&bdi->wb_lock);
+ spin_lock_bh(&bdi->wb_lock);
if (!list_empty(&bdi->work_list)) {
work = list_entry(bdi->work_list.next,
struct wb_writeback_work, list);
list_del_init(&work->list);
}
- spin_unlock(&bdi->wb_lock);
+ spin_unlock_bh(&bdi->wb_lock);
return work;
}
struct wb_writeback_work *work;
long wrote = 0;
+ set_bit(BDI_writeback_running, &wb->bdi->state);
while ((work = get_next_work_item(bdi)) != NULL) {
/*
* Override sync mode, in case we must wait for completion
* Check for periodic writeback, kupdated() style
*/
wrote += wb_check_old_data_flush(wb);
+ clear_bit(BDI_writeback_running, &wb->bdi->state);
return wrote;
}
{
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;
current->flags |= PF_FLUSHER | PF_SWAPWRITE;
set_freezable();
+ wb->last_active = jiffies;
/*
* 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()) {
+ /*
+ * Remove own delayed wake-up timer, since we are already awake
+ * and we'll take care of the preriodic write-back.
+ */
+ del_timer(&wb->wakeup_timer);
+
pages_written = wb_do_writeback(wb, 0);
trace_writeback_pages_written(pages_written);
if (pages_written)
- last_active = jiffies;
- else if (wait_jiffies != -1UL) {
- unsigned long max_idle;
-
- /*
- * Longest period of inactivity that we tolerate. If we
- * see dirty data again later, the thread will get
- * recreated automatically.
- */
- max_idle = max(5UL * 60 * HZ, wait_jiffies);
- if (time_after(jiffies, max_idle + last_active))
- break;
- }
+ wb->last_active = jiffies;
set_current_state(TASK_INTERRUPTIBLE);
- if (!list_empty(&bdi->work_list)) {
+ if (!list_empty(&bdi->work_list) || kthread_should_stop()) {
__set_current_state(TASK_RUNNING);
continue;
}
- if (dirty_writeback_interval) {
- wait_jiffies = msecs_to_jiffies(dirty_writeback_interval * 10);
- schedule_timeout(wait_jiffies);
- } else
+ if (wb_has_dirty_io(wb) && dirty_writeback_interval)
+ schedule_timeout(msecs_to_jiffies(dirty_writeback_interval * 10));
+ else {
+ /*
+ * We have nothing to do, so can go sleep without any
+ * timeout and save power. When a work is queued or
+ * something is made dirty - we will be woken up.
+ */
schedule();
+ }
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.
- */
+ /* Flush any work that raced with us exiting */
if (!list_empty(&bdi->work_list))
wb_do_writeback(wb, 1);
void __mark_inode_dirty(struct inode *inode, int flags)
{
struct super_block *sb = inode->i_sb;
+ struct backing_dev_info *bdi = NULL;
+ bool wakeup_bdi = false;
/*
* Don't do this for I_DIRTY_PAGES - that doesn't actually
if (hlist_unhashed(&inode->i_hash))
goto out;
}
- if (inode->i_state & (I_FREEING|I_CLEAR))
+ if (inode->i_state & I_FREEING)
goto out;
/*
* reposition it (that would break b_dirty time-ordering).
*/
if (!was_dirty) {
- struct bdi_writeback *wb = &inode_to_bdi(inode)->wb;
- struct backing_dev_info *bdi = wb->bdi;
-
- if (bdi_cap_writeback_dirty(bdi) &&
- !test_bit(BDI_registered, &bdi->state)) {
- WARN_ON(1);
- printk(KERN_ERR "bdi-%s not registered\n",
- bdi->name);
+ bdi = inode_to_bdi(inode);
+
+ if (bdi_cap_writeback_dirty(bdi)) {
+ WARN(!test_bit(BDI_registered, &bdi->state),
+ "bdi-%s not registered\n", bdi->name);
+
+ /*
+ * If this is the first dirty inode for this
+ * bdi, we have to wake-up the corresponding
+ * bdi thread to make sure background
+ * write-back happens later.
+ */
+ if (!wb_has_dirty_io(&bdi->wb))
+ wakeup_bdi = true;
}
inode->dirtied_when = jiffies;
- list_move(&inode->i_list, &wb->b_dirty);
+ list_move(&inode->i_list, &bdi->wb.b_dirty);
}
}
out:
spin_unlock(&inode_lock);
+
+ if (wakeup_bdi)
+ bdi_wakeup_thread_delayed(bdi);
}
EXPORT_SYMBOL(__mark_inode_dirty);
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)