LU-15216 lmv: improve MDT QOS space balance

[fs/lustre-release.git] / lustre / lmv / lmv_obd.c

diff --git a/lustre/lmv/lmv_obd.c b/lustre/lmv/lmv_obd.c
index 38a2c97..1a1e699 100644 (file)
--- a/lustre/lmv/lmv_obd.c
+++ b/lustre/lmv/lmv_obd.c
@@ -1501,10 +1501,11 @@ static struct lu_tgt_desc *lmv_locate_tgt_qos(struct lmv_obd *lmv, __u32 mdt,
 
        /* if current MDT has above-average space, within range of the QOS
         * threshold, stay on the same MDT to avoid creating needless remote
-        * MDT directories. It's more likely for low level directories.
+        * MDT directories. It's more likely for low level directories
+        * "16 / (dir_depth + 10)" is the factor to make it more unlikely for
+        * top level directories, while more likely for low levels.
         */
-       rand = total_avail * (256 - lmv->lmv_qos.lq_threshold_rr) /
-              (total_usable * 256 * (1 + dir_depth / 4));
+       rand = total_avail * 16 / (total_usable * (dir_depth + 10));
        if (cur && cur->ltd_qos.ltq_avail >= rand) {
                tgt = cur;
                GOTO(unlock, tgt);