[PATCH 1/3] mm/page-writeback.c: Rename BANDWIDTH_INTERVAL to UPDATE_INTERVAL

From: Tang Yizhou
Date: Wed Oct 02 2024 - 08:26:58 EST


From: Tang Yizhou <yizhou.tang@xxxxxxxxxx>

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 UPDATE_INTERVAL to make things clear.

This patche doesn't introduce any behavioral changes.

Signed-off-by: Tang Yizhou <yizhou.tang@xxxxxxxxxx>
---
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..a848e7f0719d 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 UPDATE_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 + UPDATE_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 + UPDATE_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))
+ UPDATE_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))
+ UPDATE_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 UPDATE_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, UPDATE_INTERVAL);
spin_unlock_irqrestore(&wb->work_lock, flags);
}

--
2.25.1