writeback: make congestion functions per bdi_writeback
Currently, all congestion functions take bdi (backing_dev_info) and
always operate on the root wb (bdi->wb) and the congestion state from
the block layer is propagated only for the root blkcg. This patch
introduces {set|clear}_wb_congested() and wb_congested() which take a
bdi_writeback_congested and bdi_writeback respectively. The bdi
counteparts are now wrappers invoking the wb based functions on
@bdi->wb.
While converting clear_bdi_congested() to clear_wb_congested(), the
local variable declaration order between @wqh and @bit is swapped for
cosmetic reason.
This patch just adds the new wb based functions. The following
patches will apply them.
v2: Updated for bdi_writeback_congested.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index 4c9386c..5029c4a 100644
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -896,31 +896,31 @@
__WAIT_QUEUE_HEAD_INITIALIZER(congestion_wqh[0]),
__WAIT_QUEUE_HEAD_INITIALIZER(congestion_wqh[1])
};
-static atomic_t nr_bdi_congested[2];
+static atomic_t nr_wb_congested[2];
-void clear_bdi_congested(struct backing_dev_info *bdi, int sync)
+void clear_wb_congested(struct bdi_writeback_congested *congested, int sync)
{
- enum wb_state bit;
wait_queue_head_t *wqh = &congestion_wqh[sync];
+ enum wb_state bit;
bit = sync ? WB_sync_congested : WB_async_congested;
- if (test_and_clear_bit(bit, &bdi->wb.congested->state))
- atomic_dec(&nr_bdi_congested[sync]);
+ if (test_and_clear_bit(bit, &congested->state))
+ atomic_dec(&nr_wb_congested[sync]);
smp_mb__after_atomic();
if (waitqueue_active(wqh))
wake_up(wqh);
}
-EXPORT_SYMBOL(clear_bdi_congested);
+EXPORT_SYMBOL(clear_wb_congested);
-void set_bdi_congested(struct backing_dev_info *bdi, int sync)
+void set_wb_congested(struct bdi_writeback_congested *congested, int sync)
{
enum wb_state bit;
bit = sync ? WB_sync_congested : WB_async_congested;
- if (!test_and_set_bit(bit, &bdi->wb.congested->state))
- atomic_inc(&nr_bdi_congested[sync]);
+ if (!test_and_set_bit(bit, &congested->state))
+ atomic_inc(&nr_wb_congested[sync]);
}
-EXPORT_SYMBOL(set_bdi_congested);
+EXPORT_SYMBOL(set_wb_congested);
/**
* congestion_wait - wait for a backing_dev to become uncongested
@@ -979,7 +979,7 @@
* encountered in the current zone, yield if necessary instead
* of sleeping on the congestion queue
*/
- if (atomic_read(&nr_bdi_congested[sync]) == 0 ||
+ if (atomic_read(&nr_wb_congested[sync]) == 0 ||
!test_bit(ZONE_CONGESTED, &zone->flags)) {
cond_resched();