diff options
| author | Michael Lyle <mlyle@lyle.org> | 2017-10-13 16:35:38 -0700 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2017-10-16 09:07:26 -0600 |
| commit | e41166c5c44e30dbd620f7c77a27efe5d5cc551a (patch) | |
| tree | ac09f29e7df62553409e7a36770e158464b4b6a2 | |
| parent | ae82ddbfeb359fcffa97be5fb5bcd59165f2864f (diff) | |
bcache: writeback rate shouldn't artifically clamp
The previous code artificially limited writeback rate to 1000000
blocks/second (NSEC_PER_MSEC), which is a rate that can be met on fast
hardware. The rate limiting code works fine (though with decreased
precision) up to 3 orders of magnitude faster, so use NSEC_PER_SEC.
Additionally, ensure that uint32_t is used as a type for rate throughout
the rate management so that type checking/clamp_t can work properly.
bch_next_delay should be rewritten for increased precision and better
handling of high rates and long sleep periods, but this is adequate for
now.
Signed-off-by: Michael Lyle <mlyle@lyle.org>
Reported-by: Coly Li <colyli@suse.de>
Reviewed-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
| -rw-r--r-- | drivers/md/bcache/bcache.h | 2 | ||||
| -rw-r--r-- | drivers/md/bcache/util.h | 4 | ||||
| -rw-r--r-- | drivers/md/bcache/writeback.c | 7 |
3 files changed, 7 insertions, 6 deletions
diff --git a/drivers/md/bcache/bcache.h b/drivers/md/bcache/bcache.h index eb83be693d60..d77c4829c497 100644 --- a/drivers/md/bcache/bcache.h +++ b/drivers/md/bcache/bcache.h @@ -361,7 +361,7 @@ struct cached_dev { int64_t writeback_rate_proportional; int64_t writeback_rate_integral; int64_t writeback_rate_integral_scaled; - int64_t writeback_rate_change; + int32_t writeback_rate_change; unsigned writeback_rate_update_seconds; unsigned writeback_rate_i_term_inverse; diff --git a/drivers/md/bcache/util.h b/drivers/md/bcache/util.h index cb8d2ccbb6c6..8f509290bb02 100644 --- a/drivers/md/bcache/util.h +++ b/drivers/md/bcache/util.h @@ -441,10 +441,10 @@ struct bch_ratelimit { uint64_t next; /* - * Rate at which we want to do work, in units per nanosecond + * Rate at which we want to do work, in units per second * The units here correspond to the units passed to bch_next_delay() */ - unsigned rate; + uint32_t rate; }; static inline void bch_ratelimit_reset(struct bch_ratelimit *d) diff --git a/drivers/md/bcache/writeback.c b/drivers/md/bcache/writeback.c index 8deb721c355e..897d28050656 100644 --- a/drivers/md/bcache/writeback.c +++ b/drivers/md/bcache/writeback.c @@ -52,7 +52,8 @@ static void __update_writeback_rate(struct cached_dev *dc) int64_t error = dirty - target; int64_t proportional_scaled = div_s64(error, dc->writeback_rate_p_term_inverse); - int64_t integral_scaled, new_rate; + int64_t integral_scaled; + uint32_t new_rate; if ((error < 0 && dc->writeback_rate_integral > 0) || (error > 0 && time_before64(local_clock(), @@ -74,8 +75,8 @@ static void __update_writeback_rate(struct cached_dev *dc) integral_scaled = div_s64(dc->writeback_rate_integral, dc->writeback_rate_i_term_inverse); - new_rate = clamp_t(int64_t, (proportional_scaled + integral_scaled), - dc->writeback_rate_minimum, NSEC_PER_MSEC); + new_rate = clamp_t(int32_t, (proportional_scaled + integral_scaled), + dc->writeback_rate_minimum, NSEC_PER_SEC); dc->writeback_rate_proportional = proportional_scaled; dc->writeback_rate_integral_scaled = integral_scaled; |