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writeback: move backing_dev_info->state into bdi_writeback

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Currently, a bdi (backing_dev_info) embeds single wb (bdi_writeback)
and the role of the separation is unclear.  For cgroup support for
writeback IOs, a bdi will be updated to host multiple wb's where each
wb serves writeback IOs of a different cgroup on the bdi.  To achieve
that, a wb should carry all states necessary for servicing writeback
IOs for a cgroup independently.

This patch moves bdi->state into wb.

* enum bdi_state is renamed to wb_state and the prefix of all enums is
  changed from BDI_ to WB_.

* Explicit zeroing of bdi->state is removed without adding zeoring of
  wb->state as the whole data structure is zeroed on init anyway.

* As there's still only one bdi_writeback per backing_dev_info, all
  uses of bdi->state are mechanically replaced with bdi->wb.state
  introducing no behavior changes.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: drbd-dev@lists.linbit.com
Cc: Neil Brown <neilb@suse.de>
Cc: Alasdair Kergon <agk@redhat.com>
Cc: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
This commit is contained in:
Tejun Heo
2015-05-22 17:13:26 -04:00
committed by Jens Axboe
parent ad7fa852d3
commit 4452226ea2
8 changed files with 38 additions and 39 deletions
Download Patch File Download Diff File Expand all files Collapse all files

20
mm/backing-dev.c
View File

@@ -96,7 +96,7 @@ static int bdi_debug_stats_show(struct seq_file *m, void *v)
nr_io,
nr_more_io,
nr_dirty_time,
!list_empty(&bdi->bdi_list), bdi->state);
!list_empty(&bdi->bdi_list), bdi->wb.state);
#undef K
return 0;
@@ -280,7 +280,7 @@ void bdi_wakeup_thread_delayed(struct backing_dev_info *bdi)
timeout = msecs_to_jiffies(dirty_writeback_interval * 10);
spin_lock_bh(&bdi->wb_lock);
if (test_bit(BDI_registered, &bdi->state))
if (test_bit(WB_registered, &bdi->wb.state))
queue_delayed_work(bdi_wq, &bdi->wb.dwork, timeout);
spin_unlock_bh(&bdi->wb_lock);
}
@@ -315,7 +315,7 @@ int bdi_register(struct backing_dev_info *bdi, struct device *parent,
bdi->dev = dev;
bdi_debug_register(bdi, dev_name(dev));
set_bit(BDI_registered, &bdi->state);
set_bit(WB_registered, &bdi->wb.state);
spin_lock_bh(&bdi_lock);
list_add_tail_rcu(&bdi->bdi_list, &bdi_list);
@@ -339,7 +339,7 @@ static void bdi_wb_shutdown(struct backing_dev_info *bdi)
{
/* Make sure nobody queues further work */
spin_lock_bh(&bdi->wb_lock);
if (!test_and_clear_bit(BDI_registered, &bdi->state)) {
if (!test_and_clear_bit(WB_registered, &bdi->wb.state)) {
spin_unlock_bh(&bdi->wb_lock);
return;
}
@@ -492,11 +492,11 @@ static atomic_t nr_bdi_congested[2];
void clear_bdi_congested(struct backing_dev_info *bdi, int sync)
{
enum bdi_state bit;
enum wb_state bit;
wait_queue_head_t *wqh = &congestion_wqh[sync];
bit = sync ? BDI_sync_congested : BDI_async_congested;
if (test_and_clear_bit(bit, &bdi->state))
bit = sync ? WB_sync_congested : WB_async_congested;
if (test_and_clear_bit(bit, &bdi->wb.state))
atomic_dec(&nr_bdi_congested[sync]);
smp_mb__after_atomic();
if (waitqueue_active(wqh))
@@ -506,10 +506,10 @@ EXPORT_SYMBOL(clear_bdi_congested);
void set_bdi_congested(struct backing_dev_info *bdi, int sync)
{
enum bdi_state bit;
enum wb_state bit;
bit = sync ? BDI_sync_congested : BDI_async_congested;
if (!test_and_set_bit(bit, &bdi->state))
bit = sync ? WB_sync_congested : WB_async_congested;
if (!test_and_set_bit(bit, &bdi->wb.state))
atomic_inc(&nr_bdi_congested[sync]);
}
EXPORT_SYMBOL(set_bdi_congested);