From: Alexander Boyko <alexander.boyko@xxxxxxx>
Current implementation of qos allocation is called for
every statfs update. It takes lq_rw_sem for write and
recalculate penalties, even whith setting qos_threshold_rr=100.
Which means always use rr allocation. Let's skip unnecessary
locking and calculation for 100% round robin allocation.
HPE-bug-id: LUS-10388
WC-bug-id: https://jira.whamcloud.com/browse/LU-15393
Lustre-commit: 2f23140d5c1396fd0 ("LU-15393 lod: skip qos for qos_threshold_rr=100")
Signed-off-by: Alexander Boyko <alexander.boyko@xxxxxxx>
Reviewed-on: https://review.whamcloud.com/46388
Reviewed-by: Andrew Perepechko <andrew.perepechko@xxxxxxx>
Reviewed-by: Alexey Lyashkov <alexey.lyashkov@xxxxxxx>
Reviewed-by: Andreas Dilger <adilger@xxxxxxxxxxxxx>
Reviewed-by: Oleg Drokin <green@xxxxxxxxxxxxx>
Signed-off-by: James Simmons <jsimmons@xxxxxxxxxxxxx>
---
fs/lustre/include/lu_object.h | 1 +
fs/lustre/lmv/lproc_lmv.c | 5 +++--
fs/lustre/obdclass/lu_tgt_descs.c | 12 ++++++++----
3 files changed, 12 insertions(+), 6 deletions(-)
diff --git a/fs/lustre/include/lu_object.h b/fs/lustre/include/lu_object.h
index 3fb40c6..e4dd287c5 100644
--- a/fs/lustre/include/lu_object.h
+++ b/fs/lustre/include/lu_object.h
@@ -1503,6 +1503,7 @@ struct lu_tgt_desc_idx {
};
/* QoS data for LOD/LMV */
+#define QOS_THRESHOLD_MAX 256 /* should be power of two */
struct lu_qos {
struct list_head lq_svr_list; /* lu_svr_qos list */
struct rw_semaphore lq_rw_sem;
diff --git a/fs/lustre/lmv/lproc_lmv.c b/fs/lustre/lmv/lproc_lmv.c
index b9efae9..6d4e8d9 100644
--- a/fs/lustre/lmv/lproc_lmv.c
+++ b/fs/lustre/lmv/lproc_lmv.c
@@ -158,7 +158,8 @@ static ssize_t qos_threshold_rr_show(struct kobject *kobj,
obd_kset.kobj);
return scnprintf(buf, PAGE_SIZE, "%u%%\n",
- (obd->u.lmv.lmv_qos.lq_threshold_rr * 100 + 255) >> 8);
+ (obd->u.lmv.lmv_qos.lq_threshold_rr * 100 +
+ (QOS_THRESHOLD_MAX - 1)) / QOS_THRESHOLD_MAX);
}
static ssize_t qos_threshold_rr_store(struct kobject *kobj,
@@ -190,7 +191,7 @@ static ssize_t qos_threshold_rr_store(struct kobject *kobj,
if (val > 100)
return -EINVAL;
- lmv->lmv_qos.lq_threshold_rr = (val << 8) / 100;
+ lmv->lmv_qos.lq_threshold_rr = (val * QOS_THRESHOLD_MAX) / 100;
set_bit(LQ_DIRTY, &lmv->lmv_qos.lq_flags);
return count;
diff --git a/fs/lustre/obdclass/lu_tgt_descs.c b/fs/lustre/obdclass/lu_tgt_descs.c
index 935cff6..51d2e21 100644
--- a/fs/lustre/obdclass/lu_tgt_descs.c
+++ b/fs/lustre/obdclass/lu_tgt_descs.c
@@ -275,11 +275,13 @@ int lu_tgt_descs_init(struct lu_tgt_descs *ltd, bool is_mdt)
ltd->ltd_lmv_desc.ld_pattern = LMV_HASH_TYPE_DEFAULT;
ltd->ltd_qos.lq_prio_free = LMV_QOS_DEF_PRIO_FREE * 256 / 100;
ltd->ltd_qos.lq_threshold_rr =
- LMV_QOS_DEF_THRESHOLD_RR_PCT * 256 / 100;
+ LMV_QOS_DEF_THRESHOLD_RR_PCT *
+ QOS_THRESHOLD_MAX / 100;
} else {
ltd->ltd_qos.lq_prio_free = LOV_QOS_DEF_PRIO_FREE * 256 / 100;
ltd->ltd_qos.lq_threshold_rr =
- LOV_QOS_DEF_THRESHOLD_RR_PCT * 256 / 100;
+ LOV_QOS_DEF_THRESHOLD_RR_PCT *
+ QOS_THRESHOLD_MAX / 100;
}
return 0;
@@ -568,8 +570,10 @@ int ltd_qos_penalties_calc(struct lu_tgt_descs *ltd)
* creation performance
*/
clear_bit(LQ_SAME_SPACE, &qos->lq_flags);
- if ((ba_max * (256 - qos->lq_threshold_rr)) >> 8 < ba_min &&
- (ia_max * (256 - qos->lq_threshold_rr)) >> 8 < ia_min) {
+ if (((ba_max * (QOS_THRESHOLD_MAX - qos->lq_threshold_rr)) /
+ QOS_THRESHOLD_MAX) < ba_min &&
+ ((ia_max * (QOS_THRESHOLD_MAX - qos->lq_threshold_rr)) /
+ QOS_THRESHOLD_MAX) < ia_min) {
set_bit(LQ_SAME_SPACE, &qos->lq_flags);
/* Reset weights for the next time we enter qos mode */
set_bit(LQ_RESET, &qos->lq_flags);
--
1.8.3.1
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