From: Tang Yizhou <yizhou.tang@shopee.com>

The name of the BANDWIDTH_INTERVAL macro is misleading, as it is not
only used in the bandwidth update functions wb_update_bandwidth() and
__wb_update_bandwidth(), but also in the dirty limit update function
domain_update_dirty_limit().

Rename BANDWIDTH_INTERVAL to BW_DIRTYLIMIT_INTERVAL to make things clear.

This patche doesn't introduce any behavioral changes.

v2: Rename UPDATE_INTERVAL to BW_DIRTYLIMIT_INTERVAL.

Signed-off-by: Tang Yizhou <yizhou.tang@shopee.com>
---
 mm/page-writeback.c | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index fcd4c1439cb9..3af7bc078dc0 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -54,9 +54,9 @@
 #define DIRTY_POLL_THRESH	(128 >> (PAGE_SHIFT - 10))
 
 /*
- * Estimate write bandwidth at 200ms intervals.
+ * Estimate write bandwidth or update dirty limit at 200ms intervals.
  */
-#define BANDWIDTH_INTERVAL	max(HZ/5, 1)
+#define BW_DIRTYLIMIT_INTERVAL	max(HZ/5, 1)
 
 #define RATELIMIT_CALC_SHIFT	10
 
@@ -1331,11 +1331,11 @@ static void domain_update_dirty_limit(struct dirty_throttle_control *dtc,
 	/*
 	 * check locklessly first to optimize away locking for the most time
 	 */
-	if (time_before(now, dom->dirty_limit_tstamp + BANDWIDTH_INTERVAL))
+	if (time_before(now, dom->dirty_limit_tstamp + BW_DIRTYLIMIT_INTERVAL))
 		return;
 
 	spin_lock(&dom->lock);
-	if (time_after_eq(now, dom->dirty_limit_tstamp + BANDWIDTH_INTERVAL)) {
+	if (time_after_eq(now, dom->dirty_limit_tstamp + BW_DIRTYLIMIT_INTERVAL)) {
 		update_dirty_limit(dtc);
 		dom->dirty_limit_tstamp = now;
 	}
@@ -1928,7 +1928,7 @@ static int balance_dirty_pages(struct bdi_writeback *wb,
 		wb->dirty_exceeded = gdtc->dirty_exceeded ||
 				     (mdtc && mdtc->dirty_exceeded);
 		if (time_is_before_jiffies(READ_ONCE(wb->bw_time_stamp) +
-					   BANDWIDTH_INTERVAL))
+					   BW_DIRTYLIMIT_INTERVAL))
 			__wb_update_bandwidth(gdtc, mdtc, true);
 
 		/* throttle according to the chosen dtc */
@@ -2705,7 +2705,7 @@ int do_writepages(struct address_space *mapping, struct writeback_control *wbc)
 	 * writeback bandwidth is updated once in a while.
 	 */
 	if (time_is_before_jiffies(READ_ONCE(wb->bw_time_stamp) +
-				   BANDWIDTH_INTERVAL))
+				   BW_DIRTYLIMIT_INTERVAL))
 		wb_update_bandwidth(wb);
 	return ret;
 }
@@ -3057,14 +3057,14 @@ static void wb_inode_writeback_end(struct bdi_writeback *wb)
 	atomic_dec(&wb->writeback_inodes);
 	/*
 	 * Make sure estimate of writeback throughput gets updated after
-	 * writeback completed. We delay the update by BANDWIDTH_INTERVAL
+	 * writeback completed. We delay the update by BW_DIRTYLIMIT_INTERVAL
 	 * (which is the interval other bandwidth updates use for batching) so
 	 * that if multiple inodes end writeback at a similar time, they get
 	 * batched into one bandwidth update.
 	 */
 	spin_lock_irqsave(&wb->work_lock, flags);
 	if (test_bit(WB_registered, &wb->state))
-		queue_delayed_work(bdi_wq, &wb->bw_dwork, BANDWIDTH_INTERVAL);
+		queue_delayed_work(bdi_wq, &wb->bw_dwork, BW_DIRTYLIMIT_INTERVAL);
 	spin_unlock_irqrestore(&wb->work_lock, flags);
 }
 
-- 
2.25.1