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path: root/drivers/md/bcache/writeback.c
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Diffstat (limited to 'drivers/md/bcache/writeback.c')
-rw-r--r--drivers/md/bcache/writeback.c53
1 files changed, 25 insertions, 28 deletions
diff --git a/drivers/md/bcache/writeback.c b/drivers/md/bcache/writeback.c
index 99053b1251be..6c44fe059c27 100644
--- a/drivers/md/bcache/writeback.c
+++ b/drivers/md/bcache/writeback.c
@@ -30,38 +30,40 @@ static void __update_writeback_rate(struct cached_dev *dc)
/* PD controller */
- int change = 0;
- int64_t error;
int64_t dirty = bcache_dev_sectors_dirty(&dc->disk);
int64_t derivative = dirty - dc->disk.sectors_dirty_last;
+ int64_t proportional = dirty - target;
+ int64_t change;
dc->disk.sectors_dirty_last = dirty;
- derivative *= dc->writeback_rate_d_term;
- derivative = clamp(derivative, -dirty, dirty);
+ /* Scale to sectors per second */
- derivative = ewma_add(dc->disk.sectors_dirty_derivative, derivative,
- dc->writeback_rate_d_smooth, 0);
+ proportional *= dc->writeback_rate_update_seconds;
+ proportional = div_s64(proportional, dc->writeback_rate_p_term_inverse);
- /* Avoid divide by zero */
- if (!target)
- goto out;
+ derivative = div_s64(derivative, dc->writeback_rate_update_seconds);
- error = div64_s64((dirty + derivative - target) << 8, target);
+ derivative = ewma_add(dc->disk.sectors_dirty_derivative, derivative,
+ (dc->writeback_rate_d_term /
+ dc->writeback_rate_update_seconds) ?: 1, 0);
+
+ derivative *= dc->writeback_rate_d_term;
+ derivative = div_s64(derivative, dc->writeback_rate_p_term_inverse);
- change = div_s64((dc->writeback_rate.rate * error) >> 8,
- dc->writeback_rate_p_term_inverse);
+ change = proportional + derivative;
/* Don't increase writeback rate if the device isn't keeping up */
if (change > 0 &&
time_after64(local_clock(),
- dc->writeback_rate.next + 10 * NSEC_PER_MSEC))
+ dc->writeback_rate.next + NSEC_PER_MSEC))
change = 0;
dc->writeback_rate.rate =
- clamp_t(int64_t, dc->writeback_rate.rate + change,
+ clamp_t(int64_t, (int64_t) dc->writeback_rate.rate + change,
1, NSEC_PER_MSEC);
-out:
+
+ dc->writeback_rate_proportional = proportional;
dc->writeback_rate_derivative = derivative;
dc->writeback_rate_change = change;
dc->writeback_rate_target = target;
@@ -87,15 +89,11 @@ static void update_writeback_rate(struct work_struct *work)
static unsigned writeback_delay(struct cached_dev *dc, unsigned sectors)
{
- uint64_t ret;
-
if (test_bit(BCACHE_DEV_DETACHING, &dc->disk.flags) ||
!dc->writeback_percent)
return 0;
- ret = bch_next_delay(&dc->writeback_rate, sectors * 10000000ULL);
-
- return min_t(uint64_t, ret, HZ);
+ return bch_next_delay(&dc->writeback_rate, sectors);
}
struct dirty_io {
@@ -241,7 +239,7 @@ static void read_dirty(struct cached_dev *dc)
if (KEY_START(&w->key) != dc->last_read ||
jiffies_to_msecs(delay) > 50)
while (!kthread_should_stop() && delay)
- delay = schedule_timeout_interruptible(delay);
+ delay = schedule_timeout_uninterruptible(delay);
dc->last_read = KEY_OFFSET(&w->key);
@@ -438,7 +436,7 @@ static int bch_writeback_thread(void *arg)
while (delay &&
!kthread_should_stop() &&
!test_bit(BCACHE_DEV_DETACHING, &dc->disk.flags))
- delay = schedule_timeout_interruptible(delay);
+ delay = schedule_timeout_uninterruptible(delay);
}
}
@@ -476,6 +474,8 @@ void bch_sectors_dirty_init(struct cached_dev *dc)
bch_btree_map_keys(&op.op, dc->disk.c, &KEY(op.inode, 0, 0),
sectors_dirty_init_fn, 0);
+
+ dc->disk.sectors_dirty_last = bcache_dev_sectors_dirty(&dc->disk);
}
int bch_cached_dev_writeback_init(struct cached_dev *dc)
@@ -490,18 +490,15 @@ int bch_cached_dev_writeback_init(struct cached_dev *dc)
dc->writeback_delay = 30;
dc->writeback_rate.rate = 1024;
- dc->writeback_rate_update_seconds = 30;
- dc->writeback_rate_d_term = 16;
- dc->writeback_rate_p_term_inverse = 64;
- dc->writeback_rate_d_smooth = 8;
+ dc->writeback_rate_update_seconds = 5;
+ dc->writeback_rate_d_term = 30;
+ dc->writeback_rate_p_term_inverse = 6000;
dc->writeback_thread = kthread_create(bch_writeback_thread, dc,
"bcache_writeback");
if (IS_ERR(dc->writeback_thread))
return PTR_ERR(dc->writeback_thread);
- set_task_state(dc->writeback_thread, TASK_INTERRUPTIBLE);
-
INIT_DELAYED_WORK(&dc->writeback_rate_update, update_writeback_rate);
schedule_delayed_work(&dc->writeback_rate_update,
dc->writeback_rate_update_seconds * HZ);