* [PATCHv2 for-next 1/4] RDMA/rtrs-clt: Add a minimum latency multipath policy
2021-04-07 10:41 [PATCHv2 for-next 0/4] New multipath policy for RTRS client Gioh Kim
@ 2021-04-07 10:42 ` Gioh Kim
2021-04-07 10:42 ` [PATCHv2 for-next 2/4] RDMA/rtrs-clt: new sysfs attribute to print the latency of each path Gioh Kim
` (2 subsequent siblings)
3 siblings, 0 replies; 5+ messages in thread
From: Gioh Kim @ 2021-04-07 10:42 UTC (permalink / raw)
To: linux-rdma
Cc: bvanassche, leon, dledford, jgg, haris.iqbal, jinpu.wang,
Gioh Kim, Gioh Kim
From: Gioh Kim <gi-oh.kim@cloud.ionos.com>
This patch adds new multipath policy: min-latency.
Client checks the latency of each path when it sends the heart-beat.
And it sends IO to the path with the minimum latency.
Signed-off-by: Gioh Kim <gi-oh.kim@ionos.com>
Signed-off-by: Jack Wang <jinpu.wang@ionos.com>
---
drivers/infiniband/ulp/rtrs/rtrs-clt-sysfs.c | 19 +++++--
drivers/infiniband/ulp/rtrs/rtrs-clt.c | 57 +++++++++++++++++++-
drivers/infiniband/ulp/rtrs/rtrs-clt.h | 1 +
drivers/infiniband/ulp/rtrs/rtrs-pri.h | 2 +
drivers/infiniband/ulp/rtrs/rtrs.c | 3 ++
5 files changed, 78 insertions(+), 4 deletions(-)
diff --git a/drivers/infiniband/ulp/rtrs/rtrs-clt-sysfs.c b/drivers/infiniband/ulp/rtrs/rtrs-clt-sysfs.c
index c502dcbae9bb..c8669d3f79f1 100644
--- a/drivers/infiniband/ulp/rtrs/rtrs-clt-sysfs.c
+++ b/drivers/infiniband/ulp/rtrs/rtrs-clt-sysfs.c
@@ -101,6 +101,9 @@ static ssize_t mpath_policy_show(struct device *dev,
case MP_POLICY_MIN_INFLIGHT:
return sysfs_emit(page, "min-inflight (MI: %d)\n",
clt->mp_policy);
+ case MP_POLICY_MIN_LATENCY:
+ return sysfs_emit(page, "min-latency (ML: %d)\n",
+ clt->mp_policy);
default:
return sysfs_emit(page, "Unknown (%d)\n", clt->mp_policy);
}
@@ -114,22 +117,32 @@ static ssize_t mpath_policy_store(struct device *dev,
struct rtrs_clt *clt;
int value;
int ret;
+ size_t len = 0;
clt = container_of(dev, struct rtrs_clt, dev);
ret = kstrtoint(buf, 10, &value);
if (!ret && (value == MP_POLICY_RR ||
- value == MP_POLICY_MIN_INFLIGHT)) {
+ value == MP_POLICY_MIN_INFLIGHT ||
+ value == MP_POLICY_MIN_LATENCY)) {
clt->mp_policy = value;
return count;
}
+ /* distinguish "mi" and "min-latency" with length */
+ len = strnlen(buf, NAME_MAX);
+ if (buf[len - 1] == '\n')
+ len--;
+
if (!strncasecmp(buf, "round-robin", 11) ||
- !strncasecmp(buf, "rr", 2))
+ (len == 2 && !strncasecmp(buf, "rr", 2)))
clt->mp_policy = MP_POLICY_RR;
else if (!strncasecmp(buf, "min-inflight", 12) ||
- !strncasecmp(buf, "mi", 2))
+ (len == 2 && !strncasecmp(buf, "mi", 2)))
clt->mp_policy = MP_POLICY_MIN_INFLIGHT;
+ else if (!strncasecmp(buf, "min-latency", 11) ||
+ (len == 2 && !strncasecmp(buf, "ml", 2)))
+ clt->mp_policy = MP_POLICY_MIN_LATENCY;
else
return -EINVAL;
diff --git a/drivers/infiniband/ulp/rtrs/rtrs-clt.c b/drivers/infiniband/ulp/rtrs/rtrs-clt.c
index 4369e4cf13f0..f3b8151052cb 100644
--- a/drivers/infiniband/ulp/rtrs/rtrs-clt.c
+++ b/drivers/infiniband/ulp/rtrs/rtrs-clt.c
@@ -633,6 +633,8 @@ static void rtrs_clt_rdma_done(struct ib_cq *cq, struct ib_wc *wc)
} else if (imm_type == RTRS_HB_ACK_IMM) {
WARN_ON(con->c.cid);
sess->s.hb_missed_cnt = 0;
+ sess->s.hb_cur_latency =
+ ktime_sub(ktime_get(), sess->s.hb_last_sent);
if (sess->flags & RTRS_MSG_NEW_RKEY_F)
return rtrs_clt_recv_done(con, wc);
} else {
@@ -831,6 +833,57 @@ static struct rtrs_clt_sess *get_next_path_min_inflight(struct path_it *it)
return min_path;
}
+/**
+ * get_next_path_min_latency() - Returns path with minimal latency.
+ * @it: the path pointer
+ *
+ * Return: a path with the lowest latency or NULL if all paths are tried
+ *
+ * Locks:
+ * rcu_read_lock() must be hold.
+ *
+ * Related to @MP_POLICY_MIN_LATENCY
+ *
+ * This DOES skip an already-tried path.
+ * There is a skip-list to skip a path if the path has tried but failed.
+ * It will try the minimum latency path and then the second minimum latency
+ * path and so on. Finally it will return NULL if all paths are tried.
+ * Therefore the caller MUST check the returned
+ * path is NULL and trigger the IO error.
+ */
+static struct rtrs_clt_sess *get_next_path_min_latency(struct path_it *it)
+{
+ struct rtrs_clt_sess *min_path = NULL;
+ struct rtrs_clt *clt = it->clt;
+ struct rtrs_clt_sess *sess;
+ ktime_t min_latency = INT_MAX;
+ ktime_t latency;
+
+ list_for_each_entry_rcu(sess, &clt->paths_list, s.entry) {
+ if (unlikely(READ_ONCE(sess->state) != RTRS_CLT_CONNECTED))
+ continue;
+
+ if (unlikely(!list_empty(raw_cpu_ptr(sess->mp_skip_entry))))
+ continue;
+
+ latency = sess->s.hb_cur_latency;
+
+ if (latency < min_latency) {
+ min_latency = latency;
+ min_path = sess;
+ }
+ }
+
+ /*
+ * add the path to the skip list, so that next time we can get
+ * a different one
+ */
+ if (min_path)
+ list_add(raw_cpu_ptr(min_path->mp_skip_entry), &it->skip_list);
+
+ return min_path;
+}
+
static inline void path_it_init(struct path_it *it, struct rtrs_clt *clt)
{
INIT_LIST_HEAD(&it->skip_list);
@@ -839,8 +892,10 @@ static inline void path_it_init(struct path_it *it, struct rtrs_clt *clt)
if (clt->mp_policy == MP_POLICY_RR)
it->next_path = get_next_path_rr;
- else
+ else if (clt->mp_policy == MP_POLICY_MIN_INFLIGHT)
it->next_path = get_next_path_min_inflight;
+ else
+ it->next_path = get_next_path_min_latency;
}
static inline void path_it_deinit(struct path_it *it)
diff --git a/drivers/infiniband/ulp/rtrs/rtrs-clt.h b/drivers/infiniband/ulp/rtrs/rtrs-clt.h
index 59ea2ec44fe5..5c0cea8dd83e 100644
--- a/drivers/infiniband/ulp/rtrs/rtrs-clt.h
+++ b/drivers/infiniband/ulp/rtrs/rtrs-clt.h
@@ -30,6 +30,7 @@ enum rtrs_clt_state {
enum rtrs_mp_policy {
MP_POLICY_RR,
MP_POLICY_MIN_INFLIGHT,
+ MP_POLICY_MIN_LATENCY,
};
/* see Documentation/ABI/testing/sysfs-class-rtrs-client for details */
diff --git a/drivers/infiniband/ulp/rtrs/rtrs-pri.h b/drivers/infiniband/ulp/rtrs/rtrs-pri.h
index 1b31bda9ca78..bcad5e2168c5 100644
--- a/drivers/infiniband/ulp/rtrs/rtrs-pri.h
+++ b/drivers/infiniband/ulp/rtrs/rtrs-pri.h
@@ -112,6 +112,8 @@ struct rtrs_sess {
unsigned int hb_interval_ms;
unsigned int hb_missed_cnt;
unsigned int hb_missed_max;
+ ktime_t hb_last_sent;
+ ktime_t hb_cur_latency;
};
/* rtrs information unit */
diff --git a/drivers/infiniband/ulp/rtrs/rtrs.c b/drivers/infiniband/ulp/rtrs/rtrs.c
index bc08b7f6e5e2..a7847282a2eb 100644
--- a/drivers/infiniband/ulp/rtrs/rtrs.c
+++ b/drivers/infiniband/ulp/rtrs/rtrs.c
@@ -337,6 +337,9 @@ static void hb_work(struct work_struct *work)
schedule_hb(sess);
return;
}
+
+ sess->hb_last_sent = ktime_get();
+
imm = rtrs_to_imm(RTRS_HB_MSG_IMM, 0);
err = rtrs_post_rdma_write_imm_empty(usr_con, sess->hb_cqe, imm,
0, NULL);
--
2.25.1
^ permalink raw reply related [flat|nested] 5+ messages in thread* [PATCHv2 for-next 2/4] RDMA/rtrs-clt: new sysfs attribute to print the latency of each path
2021-04-07 10:41 [PATCHv2 for-next 0/4] New multipath policy for RTRS client Gioh Kim
2021-04-07 10:42 ` [PATCHv2 for-next 1/4] RDMA/rtrs-clt: Add a minimum latency multipath policy Gioh Kim
@ 2021-04-07 10:42 ` Gioh Kim
2021-04-07 10:42 ` [PATCHv2 for-next 3/4] RDMA/rtrs-clt: Check state of the rtrs_clt_sess before reading its stats Gioh Kim
2021-04-07 10:42 ` [PATCHv2 for-next 4/4] Documentation/ABI/rtrs-clt: Add descriptions for min-latency policy Gioh Kim
3 siblings, 0 replies; 5+ messages in thread
From: Gioh Kim @ 2021-04-07 10:42 UTC (permalink / raw)
To: linux-rdma
Cc: bvanassche, leon, dledford, jgg, haris.iqbal, jinpu.wang,
Gioh Kim, Gioh Kim
From: Gioh Kim <gi-oh.kim@cloud.ionos.com>
It shows the latest latency that the client checked when sending
the heart-beat.
Signed-off-by: Gioh Kim <gi-oh.kim@ionos.com>
Signed-off-by: Jack Wang <jinpu.wang@ionos.com>
---
drivers/infiniband/ulp/rtrs/rtrs-clt-sysfs.c | 16 ++++++++++++++++
1 file changed, 16 insertions(+)
diff --git a/drivers/infiniband/ulp/rtrs/rtrs-clt-sysfs.c b/drivers/infiniband/ulp/rtrs/rtrs-clt-sysfs.c
index c8669d3f79f1..e2673a17b6a3 100644
--- a/drivers/infiniband/ulp/rtrs/rtrs-clt-sysfs.c
+++ b/drivers/infiniband/ulp/rtrs/rtrs-clt-sysfs.c
@@ -355,6 +355,21 @@ static ssize_t rtrs_clt_hca_name_show(struct kobject *kobj,
static struct kobj_attribute rtrs_clt_hca_name_attr =
__ATTR(hca_name, 0444, rtrs_clt_hca_name_show, NULL);
+static ssize_t rtrs_clt_cur_latency_show(struct kobject *kobj,
+ struct kobj_attribute *attr,
+ char *page)
+{
+ struct rtrs_clt_sess *sess;
+
+ sess = container_of(kobj, struct rtrs_clt_sess, kobj);
+
+ return scnprintf(page, PAGE_SIZE, "%lld ns\n",
+ ktime_to_ns(sess->s.hb_cur_latency));
+}
+
+static struct kobj_attribute rtrs_clt_cur_latency_attr =
+ __ATTR(cur_latency, 0444, rtrs_clt_cur_latency_show, NULL);
+
static ssize_t rtrs_clt_src_addr_show(struct kobject *kobj,
struct kobj_attribute *attr,
char *page)
@@ -398,6 +413,7 @@ static struct attribute *rtrs_clt_sess_attrs[] = {
&rtrs_clt_reconnect_attr.attr,
&rtrs_clt_disconnect_attr.attr,
&rtrs_clt_remove_path_attr.attr,
+ &rtrs_clt_cur_latency_attr.attr,
NULL,
};
--
2.25.1
^ permalink raw reply related [flat|nested] 5+ messages in thread* [PATCHv2 for-next 3/4] RDMA/rtrs-clt: Check state of the rtrs_clt_sess before reading its stats
2021-04-07 10:41 [PATCHv2 for-next 0/4] New multipath policy for RTRS client Gioh Kim
2021-04-07 10:42 ` [PATCHv2 for-next 1/4] RDMA/rtrs-clt: Add a minimum latency multipath policy Gioh Kim
2021-04-07 10:42 ` [PATCHv2 for-next 2/4] RDMA/rtrs-clt: new sysfs attribute to print the latency of each path Gioh Kim
@ 2021-04-07 10:42 ` Gioh Kim
2021-04-07 10:42 ` [PATCHv2 for-next 4/4] Documentation/ABI/rtrs-clt: Add descriptions for min-latency policy Gioh Kim
3 siblings, 0 replies; 5+ messages in thread
From: Gioh Kim @ 2021-04-07 10:42 UTC (permalink / raw)
To: linux-rdma
Cc: bvanassche, leon, dledford, jgg, haris.iqbal, jinpu.wang,
Md Haris Iqbal, Gioh Kim
From: Md Haris Iqbal <haris.iqbal@cloud.ionos.com>
KASAN detected the following BUG:
[ 230.436512] ==================================================================
[ 230.437182] BUG: KASAN: use-after-free in get_next_path_min_inflight+0x95/0x150 [rtrs_client]
[ 230.437632] Read of size 4 at addr ffff88a796b4bb50 by task fio/4130
[ 230.438069] CPU: 32 PID: 4130 Comm: fio Tainted: G O 5.4.84-pserver #5.4.84-1+feature+linux+5.4.y+dbg+20201216.1319+b6b887b~deb10
[ 230.438079] Hardware name: Supermicro H8QG6/H8QG6, BIOS 3.00 09/04/2012
[ 230.438088] Call Trace:
[ 230.438111] dump_stack+0x96/0xe0
[ 230.438136] print_address_description.constprop.4+0x1f/0x300
[ 230.438150] ? irq_work_claim+0x2e/0x50
[ 230.438172] __kasan_report.cold.8+0x78/0x92
[ 230.438203] ? get_next_path_min_inflight+0x95/0x150 [rtrs_client]
[ 230.438234] kasan_report+0x10/0x20
[ 230.438249] check_memory_region+0x144/0x1c0
[ 230.438274] get_next_path_min_inflight+0x95/0x150 [rtrs_client]
[ 230.438312] rtrs_clt_request+0x1fe/0x700 [rtrs_client]
[ 230.438364] ? rtrs_clt_close_work+0x40/0x40 [rtrs_client]
[ 230.438395] ? rtrs_clt_change_state_get_old+0x70/0x70 [rtrs_client]
[ 230.438417] ? blk_mq_start_request+0x1a4/0x2c0
[ 230.438430] ? blk_rq_map_sg+0x3d5/0xaa0
[ 230.438468] ? round_jiffies_up+0x60/0x90
[ 230.438511] rnbd_queue_rq+0x3e2/0x870 [rnbd_client]
[ 230.438567] ? rnbd_softirq_done_fn+0x90/0x90 [rnbd_client]
[ 230.438587] ? rnbd_get_permit+0x50/0x50 [rnbd_client]
[ 230.438601] ? __lock_acquire+0x68e/0x23a0
[ 230.438635] ? blk_mq_get_driver_tag+0xbe/0x250
[ 230.438652] ? blk_mq_dequeue_from_ctx+0x4d0/0x4d0
[ 230.438663] ? lock_acquire+0xf3/0x210
[ 230.438726] __blk_mq_try_issue_directly+0x272/0x390
[ 230.438752] ? blk_mq_get_driver_tag+0x250/0x250
[ 230.438785] ? rcu_is_watching+0x34/0x50
[ 230.438816] blk_mq_request_issue_directly+0xa8/0xf0
[ 230.438833] ? blk_mq_flush_plug_list+0x690/0x690
[ 230.438859] ? lock_downgrade+0x390/0x390
[ 230.438892] ? lock_acquire+0xf3/0x210
[ 230.438920] blk_mq_try_issue_list_directly+0xa1/0x160
[ 230.438952] blk_mq_sched_insert_requests+0x23c/0x390
[ 230.438992] blk_mq_flush_plug_list+0x361/0x690
[ 230.439037] ? blk_mq_insert_requests+0x300/0x300
[ 230.439058] ? current_time+0x8c/0xe0
[ 230.439074] ? timestamp_truncate+0x180/0x180
[ 230.439101] ? file_remove_privs+0xb4/0x1f0
[ 230.439139] blk_flush_plug_list+0x1d1/0x210
[ 230.439167] ? blk_insert_cloned_request+0x1e0/0x1e0
[ 230.439220] blk_finish_plug+0x3c/0x54
[ 230.439243] blkdev_write_iter+0x173/0x260
[ 230.439272] ? bd_finish_claiming+0xe0/0xe0
[ 230.439298] ? 0xffffffff9a000000
[ 230.439330] ? rw_verify_area+0xd9/0x130
[ 230.439359] aio_write+0x1d3/0x300
[ 230.439387] ? aio_read+0x260/0x260
[ 230.439477] ? lock_downgrade+0x390/0x390
[ 230.439497] ? lock_acquire+0xf3/0x210
[ 230.439512] ? __might_fault+0x7d/0xe0
[ 230.439570] io_submit_one+0xccc/0x1920
[ 230.439633] ? aio_poll_complete_work+0x850/0x850
[ 230.439735] ? __x64_sys_io_submit+0x118/0x380
[ 230.439748] __x64_sys_io_submit+0x118/0x380
[ 230.439777] ? __ia32_compat_sys_io_submit+0x360/0x360
[ 230.439793] ? __x64_sys_io_getevents+0xd7/0x150
[ 230.439807] ? mark_held_locks+0x29/0xa0
[ 230.439827] ? entry_SYSCALL_64_after_hwframe+0x3e/0xbe
[ 230.439840] ? trace_hardirqs_off_caller+0x15/0x110
[ 230.439857] ? mark_held_locks+0x29/0xa0
[ 230.439893] ? do_syscall_64+0x68/0x270
[ 230.439903] do_syscall_64+0x68/0x270
[ 230.439924] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[ 230.439936] RIP: 0033:0x7f8f10233f59
[ 230.439948] Code: 00 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 07 6f 0c 00 f7 d8 64 89 01 48
[ 230.439958] RSP: 002b:00007fff1df1d238 EFLAGS: 00000246 ORIG_RAX: 00000000000000d1
[ 230.439970] RAX: ffffffffffffffda RBX: 00007f8f104ec360 RCX: 00007f8f10233f59
[ 230.439980] RDX: 0000555c4c1f9440 RSI: 0000000000000001 RDI: 00007f8f04730000
[ 230.439989] RBP: 00007f8f04730000 R08: 0000555c4c1c97f0 R09: 00000000000001e0
[ 230.439998] R10: 0000555c4c1f9670 R11: 0000000000000246 R12: 0000000000000001
[ 230.440007] R13: 0000000000000000 R14: 0000555c4c1f9440 R15: 00007f8ee30b5210
[ 230.440257] Allocated by task 3440:
[ 230.440471] save_stack+0x19/0x80
[ 230.440482] __kasan_kmalloc.constprop.9+0xc1/0xd0
[ 230.440492] kmem_cache_alloc_trace+0x15b/0x350
[ 230.440508] alloc_sess+0xf4/0x570 [rtrs_client]
[ 230.440524] rtrs_clt_open+0x3b4/0x780 [rtrs_client]
[ 230.440538] find_and_get_or_create_sess+0x649/0x9d0 [rnbd_client]
[ 230.440551] rnbd_clt_map_device+0xd7/0xf50 [rnbd_client]
[ 230.440565] rnbd_clt_map_device_store+0x4ee/0x970 [rnbd_client]
[ 230.440577] kernfs_fop_write+0x141/0x240
[ 230.440587] vfs_write+0xf3/0x280
[ 230.440598] ksys_write+0xba/0x150
[ 230.440608] do_syscall_64+0x68/0x270
[ 230.440619] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[ 230.440806] Freed by task 4148:
[ 230.441013] save_stack+0x19/0x80
[ 230.441024] __kasan_slab_free+0x125/0x170
[ 230.441034] kfree+0xe7/0x3f0
[ 230.441045] kobject_put+0xd3/0x240
[ 230.441061] rtrs_clt_destroy_sess_files+0x3f/0x60 [rtrs_client]
[ 230.441076] rtrs_clt_remove_path_from_sysfs+0x95/0xe0 [rtrs_client]
[ 230.441092] rtrs_clt_remove_path_store+0x3e/0xa0 [rtrs_client]
[ 230.441103] kernfs_fop_write+0x141/0x240
[ 230.441113] vfs_write+0xf3/0x280
[ 230.441123] ksys_write+0xba/0x150
[ 230.441133] do_syscall_64+0x68/0x270
[ 230.441145] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[ 230.441333] The buggy address belongs to the object at ffff88a796b4bb00
which belongs to the cache kmalloc-96 of size 96
[ 230.441705] The buggy address is located 80 bytes inside of
96-byte region [ffff88a796b4bb00, ffff88a796b4bb60)
[ 230.442063] The buggy address belongs to the page:
[ 230.442294] page:ffffea009e5ad2c0 refcount:1 mapcount:0 mapping:ffff8887c6016e00 index:0x0
[ 230.442305] flags: 0x12ffff8000000200(slab)
[ 230.442320] raw: 12ffff8000000200 dead000000000100 dead000000000122 ffff8887c6016e00
[ 230.442332] raw: 0000000000000000 0000000000200020 00000001ffffffff 0000000000000000
[ 230.442340] page dumped because: kasan: bad access detected
[ 230.442525] Memory state around the buggy address:
[ 230.442756] ffff88a796b4ba00: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
[ 230.443059] ffff88a796b4ba80: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
[ 230.443359] >ffff88a796b4bb00: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
[ 230.443681] ^
[ 230.443935] ffff88a796b4bb80: 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc
[ 230.444233] ffff88a796b4bc00: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
[ 230.444529] ==================================================================
When get_next_path_min_inflight is called to select the next path, it
iterates over the list of available rtrs_clt_sess (paths). It then reads
the number of inflight IOs for that path to select one which has the least
But it may so happen that that rtrs_clt_sess (path) is no longer in the
connected state, and like in the above BUG its resources have also been
freed.
So, check the state of the rtrs_clt_sess (path) before going ahead to read
its inflight stats.
Signed-off-by: Md Haris Iqbal <haris.iqbal@ionos.com>
Reviewed-by: Gioh Kim <gi-oh.kim@ionos.com>
Signed-off-by: Jack Wang <jinpu.wang@ionos.com>
---
drivers/infiniband/ulp/rtrs/rtrs-clt.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/infiniband/ulp/rtrs/rtrs-clt.c b/drivers/infiniband/ulp/rtrs/rtrs-clt.c
index f3b8151052cb..96029d4ec26f 100644
--- a/drivers/infiniband/ulp/rtrs/rtrs-clt.c
+++ b/drivers/infiniband/ulp/rtrs/rtrs-clt.c
@@ -812,6 +812,9 @@ static struct rtrs_clt_sess *get_next_path_min_inflight(struct path_it *it)
int inflight;
list_for_each_entry_rcu(sess, &clt->paths_list, s.entry) {
+ if (unlikely(READ_ONCE(sess->state) != RTRS_CLT_CONNECTED))
+ continue;
+
if (unlikely(!list_empty(raw_cpu_ptr(sess->mp_skip_entry))))
continue;
--
2.25.1
^ permalink raw reply related [flat|nested] 5+ messages in thread* [PATCHv2 for-next 4/4] Documentation/ABI/rtrs-clt: Add descriptions for min-latency policy
2021-04-07 10:41 [PATCHv2 for-next 0/4] New multipath policy for RTRS client Gioh Kim
` (2 preceding siblings ...)
2021-04-07 10:42 ` [PATCHv2 for-next 3/4] RDMA/rtrs-clt: Check state of the rtrs_clt_sess before reading its stats Gioh Kim
@ 2021-04-07 10:42 ` Gioh Kim
3 siblings, 0 replies; 5+ messages in thread
From: Gioh Kim @ 2021-04-07 10:42 UTC (permalink / raw)
To: linux-rdma
Cc: bvanassche, leon, dledford, jgg, haris.iqbal, jinpu.wang, Gioh Kim
describe new multipath policy min-latency of the RTRS client.
Signed-off-by: Gioh Kim <gi-oh.kim@ionos.com>
Signed-off-by: Jack Wang <jinpu.wang@ionos.com>
---
Documentation/ABI/testing/sysfs-class-rtrs-client | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/Documentation/ABI/testing/sysfs-class-rtrs-client b/Documentation/ABI/testing/sysfs-class-rtrs-client
index 0f7165aab251..49a4157c7bf1 100644
--- a/Documentation/ABI/testing/sysfs-class-rtrs-client
+++ b/Documentation/ABI/testing/sysfs-class-rtrs-client
@@ -34,6 +34,9 @@ Description: Multipath policy specifies which path should be selected on each IO
min-inflight (1):
select path with minimum inflights.
+ min-latency (2):
+ select path with minimum latency.
+
What: /sys/class/rtrs-client/<session-name>/paths/
Date: Feb 2020
KernelVersion: 5.7
@@ -95,6 +98,15 @@ KernelVersion: 5.7
Contact: Jack Wang <jinpu.wang@cloud.ionos.com> Danil Kipnis <danil.kipnis@cloud.ionos.com>
Description: RO, Contains the destination address of the path
+What: /sys/class/rtrs-client/<session-name>/paths/<src@dst>/cur_latency
+Date: Feb 2020
+KernelVersion: 5.7
+Contact: Jack Wang <jinpu.wang@cloud.ionos.com> Danil Kipnis <danil.kipnis@cloud.ionos.com>
+Description: RO, Contains the latency time calculated by the heart-beat messages.
+ Whenever the client sends heart-beat message, it checks the time gap
+ between sending the heart-beat message and receiving the ACK.
+ This value can be changed regularly.
+
What: /sys/class/rtrs-client/<session-name>/paths/<src@dst>/stats/reset_all
Date: Feb 2020
KernelVersion: 5.7
--
2.25.1
^ permalink raw reply related [flat|nested] 5+ messages in thread