diff options
Diffstat (limited to 'block/blk-wbt.h')
| -rw-r--r-- | block/blk-wbt.h | 20 |
1 files changed, 16 insertions, 4 deletions
diff --git a/block/blk-wbt.h b/block/blk-wbt.h index e7c086374e20..a6470175ac9e 100644 --- a/block/blk-wbt.h +++ b/block/blk-wbt.h @@ -9,16 +9,28 @@ #include "blk-stat.h" +/* + * First bit is tracked or not, next two bits is a value shifted up + */ enum wbt_flags { WBT_TRACKED = 1, /* write, tracked for throttling */ - WBT_READ = 2, /* read */ - WBT_KSWAPD = 4, /* write, from kswapd */ + WBT_KSWAPD = 2, + WBT_ODIRECT = 4, WBT_NR_BITS = 3, /* number of bits */ }; +/* + * We have three buckets for accounting and waiting - one for buffered + * IO, one for kswapd, and one for O_DIRECT writes. This helps us ensure + * fairness between different types of writes, without starving one of + * them unnecessarily. + */ enum { - WBT_NUM_RWQ = 2, + WBT_RWQ_BUFFERED = 0, + WBT_RWQ_KSWAPD, + WBT_RWQ_ODIRECT, + WBT_NUM_RWQ, }; /* @@ -52,7 +64,7 @@ static inline bool wbt_is_tracked(struct blk_issue_stat *stat) static inline bool wbt_is_read(struct blk_issue_stat *stat) { - return (stat->stat >> BLK_STAT_RES_SHIFT) & WBT_READ; + return (stat->stat >> BLK_STAT_RES_SHIFT) == 0; } struct rq_wait { |