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Subject[PATCH v2 3/3] md/bitmap: Convert daemon_work to proper timer
Date
It was observed that with certain high I/O workloads that the daemon
work may never run, preventing the bitmap from fully flushing. Ensure
the bitmap fully flushes by converting the daemon worker to a proper
timer.

Signed-off-by: Jonathan Derrick <jonathan.derrick@linux.dev>
---
drivers/md/md-bitmap.c | 30 +++++++++++++-----------------
drivers/md/md-bitmap.h | 3 +--
drivers/md/md.c | 9 +++++++--
drivers/md/md.h | 1 +
4 files changed, 22 insertions(+), 21 deletions(-)

diff --git a/drivers/md/md-bitmap.c b/drivers/md/md-bitmap.c
index cd8250368860..34feb906243f 100644
--- a/drivers/md/md-bitmap.c
+++ b/drivers/md/md-bitmap.c
@@ -1250,8 +1250,9 @@ static bitmap_counter_t *md_bitmap_get_counter(struct bitmap_counts *bitmap,
* out to disk
*/

-void md_bitmap_daemon_work(struct mddev *mddev)
+void md_bitmap_daemon_work(struct timer_list *t)
{
+ struct mddev *mddev = from_timer(mddev, t, daemon_timer);
struct bitmap *bitmap;
unsigned long j;
unsigned long nextpage;
@@ -1267,11 +1268,7 @@ void md_bitmap_daemon_work(struct mddev *mddev)
mutex_unlock(&mddev->bitmap_info.mutex);
return;
}
- if (time_before(jiffies, bitmap->daemon_lastrun
- + mddev->bitmap_info.daemon_sleep))
- goto done;

- bitmap->daemon_lastrun = jiffies;
if (bitmap->allclean) {
mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
goto done;
@@ -1372,6 +1369,7 @@ void md_bitmap_daemon_work(struct mddev *mddev)
if (bitmap->allclean == 0)
mddev->thread->timeout =
mddev->bitmap_info.daemon_sleep;
+ mod_timer(&mddev->daemon_timer, jiffies + mddev->bitmap_info.daemon_sleep);
mutex_unlock(&mddev->bitmap_info.mutex);
}

@@ -1735,21 +1733,16 @@ void md_bitmap_dirty_bits(struct bitmap *bitmap, unsigned long s, unsigned long
void md_bitmap_flush(struct mddev *mddev)
{
struct bitmap *bitmap = mddev->bitmap;
- long sleep;

if (!bitmap) /* there was no bitmap */
return;

/* run the daemon_work three time to ensure everything is flushed
- * that can be
- */
- sleep = mddev->bitmap_info.daemon_sleep * 2;
- bitmap->daemon_lastrun -= sleep;
- md_bitmap_daemon_work(mddev);
- bitmap->daemon_lastrun -= sleep;
- md_bitmap_daemon_work(mddev);
- bitmap->daemon_lastrun -= sleep;
- md_bitmap_daemon_work(mddev);
+ * that can be
+ */
+ md_bitmap_daemon_work(&mddev->daemon_timer);
+ md_bitmap_daemon_work(&mddev->daemon_timer);
+ md_bitmap_daemon_work(&mddev->daemon_timer);
if (mddev->bitmap_info.external)
md_super_wait(mddev);
md_bitmap_update_sb(bitmap);
@@ -1826,7 +1819,7 @@ void md_bitmap_destroy(struct mddev *mddev)
mutex_unlock(&mddev->bitmap_info.mutex);
if (mddev->thread)
mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
-
+ del_timer_sync(&mddev->daemon_timer);
md_bitmap_free(bitmap);
}

@@ -1904,7 +1897,10 @@ struct bitmap *md_bitmap_create(struct mddev *mddev, int slot)
if (err)
goto error;

- bitmap->daemon_lastrun = jiffies;
+ timer_setup(&mddev->daemon_timer, md_bitmap_daemon_work, 0);
+ mddev->daemon_timer.expires = jiffies + mddev->bitmap_info.daemon_sleep;
+ add_timer(&mddev->daemon_timer);
+
err = md_bitmap_resize(bitmap, blocks, mddev->bitmap_info.chunksize, 1);
if (err)
goto error;
diff --git a/drivers/md/md-bitmap.h b/drivers/md/md-bitmap.h
index 49a93d8ff307..b7e8f2266bf2 100644
--- a/drivers/md/md-bitmap.h
+++ b/drivers/md/md-bitmap.h
@@ -220,7 +220,6 @@ struct bitmap {
* the bitmap daemon - periodically wakes up and sweeps the bitmap
* file, cleaning up bits and flushing out pages to disk as necessary
*/
- unsigned long daemon_lastrun; /* jiffies of last run */
unsigned long last_end_sync; /* when we lasted called end_sync to
* update bitmap with resync progress */
unsigned long unplugged_count; /* last dirty count from md_bitmap_unplug */
@@ -265,7 +264,7 @@ void md_bitmap_sync_with_cluster(struct mddev *mddev,
sector_t new_lo, sector_t new_hi);

void md_bitmap_unplug(struct bitmap *bitmap);
-void md_bitmap_daemon_work(struct mddev *mddev);
+void md_bitmap_daemon_work(struct timer_list *t);

int md_bitmap_resize(struct bitmap *bitmap, sector_t blocks,
int chunksize, int init);
diff --git a/drivers/md/md.c b/drivers/md/md.c
index afaf36b2f6ab..9f8a9f62b3db 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -9265,8 +9265,13 @@ void md_check_recovery(struct mddev *mddev)
if (mddev->suspended)
return;

- if (mddev->bitmap)
- md_bitmap_daemon_work(mddev);
+ if (mddev->bitmap) {
+ spin_lock(&pers_lock);
+ if (mddev->bitmap->allclean == 0)
+ mddev->thread->timeout =
+ mddev->bitmap_info.daemon_sleep;
+ spin_unlock(&pers_lock);
+ }

if (signal_pending(current)) {
if (mddev->pers->sync_request && !mddev->external) {
diff --git a/drivers/md/md.h b/drivers/md/md.h
index 1a558cb18bd4..578cc496c325 100644
--- a/drivers/md/md.h
+++ b/drivers/md/md.h
@@ -503,6 +503,7 @@ struct mddev {
char cluster_name[64]; /* Name of the cluster */
unsigned int flush_threshold; /* how many dirty chunks between updates */
} bitmap_info;
+ struct timer_list daemon_timer;

atomic_t max_corr_read_errors; /* max read retries */
struct list_head all_mddevs;
--
2.31.1
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