bcache: update bucket_in_use in real time
bucket_in_use is updated in gc thread which triggered by invalidating or
writing sectors_to_gc dirty data, It's a long interval. Therefore, when we
use it to compare with the threshold, it is often not timely, which leads
to inaccurate judgment and often results in bucket depletion.
We have send a patch before, by the means of updating bucket_in_use
periodically In gc thread, which Coly thought that would lead high
latency, In this patch, we add avail_nbuckets to record the count of
available buckets, and we calculate bucket_in_use when alloc or free
bucket in real time.
[edited by ML: eliminated some whitespace errors]
Signed-off-by: Tang Junhui <[email protected]>
Signed-off-by: Michael Lyle <[email protected]>
Reviewed-by: Michael Lyle <[email protected]>
Reviewed-by: Coly Li <[email protected]>
Signed-off-by: Jens Axboe <[email protected]>
diff --git a/drivers/md/bcache/bcache.h b/drivers/md/bcache/bcache.h
index 363ea62..e274082 100644
--- a/drivers/md/bcache/bcache.h
+++ b/drivers/md/bcache/bcache.h
@@ -581,6 +581,7 @@ struct cache_set {
uint8_t need_gc;
struct gc_stat gc_stats;
size_t nbuckets;
+ size_t avail_nbuckets;
struct task_struct *gc_thread;
/* Where in the btree gc currently is */
