From: Tang Junhui <tang.junhui@xxxxxxxxxx>
When there is not enough data in writeback cache, let the writeback rate
to be 0, and delay 30 seconds in read_dirty().
Signed-off-by: Tang Junhui <tang.junhui@xxxxxxxxxx>
---
drivers/md/bcache/util.c | 15 ++++++++++-----
drivers/md/bcache/writeback.c | 2 +-
2 files changed, 11 insertions(+), 6 deletions(-)
diff --git a/drivers/md/bcache/util.c b/drivers/md/bcache/util.c
index dde6172..ba40f01 100644
--- a/drivers/md/bcache/util.c
+++ b/drivers/md/bcache/util.c
@@ -209,13 +209,18 @@ uint64_t bch_next_delay(struct bch_ratelimit *d, uint64_t done)
{
uint64_t now = local_clock();
- d->next += div_u64(done * NSEC_PER_SEC, d->rate);
+ if (!d->rate) {
+ d->next += ZERO_RATE_DELAY_NS;
+ }
+ else {
+ d->next += div_u64(done * NSEC_PER_SEC, d->rate);
- if (time_before64(now + NSEC_PER_SEC, d->next))
- d->next = now + NSEC_PER_SEC;
+ if (time_before64(now + NSEC_PER_SEC, d->next))
+ d->next = now + NSEC_PER_SEC;
- if (time_after64(now - NSEC_PER_SEC * 2, d->next))
- d->next = now - NSEC_PER_SEC * 2;
+ if (time_after64(now - NSEC_PER_SEC * 2, d->next))
+ d->next = now - NSEC_PER_SEC * 2;
+ }
return time_after64(d->next, now)
? div_u64(d->next - now, NSEC_PER_SEC / HZ)
diff --git a/drivers/md/bcache/writeback.c b/drivers/md/bcache/writeback.c
index 69e1ae5..8fac280 100644
--- a/drivers/md/bcache/writeback.c
+++ b/drivers/md/bcache/writeback.c
@@ -60,7 +60,7 @@ static void __update_writeback_rate(struct cached_dev *dc)
dc->writeback_rate.rate =
clamp_t(int64_t, (int64_t) dc->writeback_rate.rate + change,
- 1, NSEC_PER_MSEC);
+ 0, NSEC_PER_MSEC);
dc->writeback_rate_proportional = proportional;
dc->writeback_rate_derivative = derivative;
--
2.8.1.windows.1
--
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