diff options
Diffstat (limited to 'drivers/md/bcache/bcache.h')
| -rw-r--r-- | drivers/md/bcache/bcache.h | 20 |
1 files changed, 19 insertions, 1 deletions
diff --git a/drivers/md/bcache/bcache.h b/drivers/md/bcache/bcache.h index b61b83bbcfff..fdf75352e16a 100644 --- a/drivers/md/bcache/bcache.h +++ b/drivers/md/bcache/bcache.h @@ -627,6 +627,20 @@ struct cache_set { struct bkey gc_done; /* + * For automatical garbage collection after writeback completed, this + * varialbe is used as bit fields, + * - 0000 0001b (BCH_ENABLE_AUTO_GC): enable gc after writeback + * - 0000 0010b (BCH_DO_AUTO_GC): do gc after writeback + * This is an optimization for following write request after writeback + * finished, but read hit rate dropped due to clean data on cache is + * discarded. Unless user explicitly sets it via sysfs, it won't be + * enabled. + */ +#define BCH_ENABLE_AUTO_GC 1 +#define BCH_DO_AUTO_GC 2 + uint8_t gc_after_writeback; + + /* * The allocation code needs gc_mark in struct bucket to be correct, but * it's not while a gc is in progress. Protected by bucket_lock. */ @@ -658,7 +672,11 @@ struct cache_set { /* * A btree node on disk could have too many bsets for an iterator to fit - * on the stack - have to dynamically allocate them + * on the stack - have to dynamically allocate them. + * bch_cache_set_alloc() will make sure the pool can allocate iterators + * equipped with enough room that can host + * (sb.bucket_size / sb.block_size) + * btree_iter_sets, which is more than static MAX_BSETS. */ mempool_t fill_iter; |