ib_modify_qp() is an expensive operation on some HCAs running
virtualized. This series removes two ib_modify_qp() calls from RDS.
I am sending this as a v3, even though it is the first sent to
net. This because the IB Core commit has reach v3.
Håkon Bugge (2):
IB/cma: Introduce rdma_set_min_rnr_timer()
rds: ib: Remove two ib_modify_qp() calls
drivers/infiniband/core/cma.c | 41 ++++++++++++++++++++++++++++++++++++++
drivers/infiniband/core/cma_priv.h | 2 ++
include/rdma/rdma_cm.h | 2 ++
net/rds/ib_cm.c | 35 +-------------------------------
net/rds/rdma_transport.c | 1 +
5 files changed, 47 insertions(+), 34 deletions(-)
--
1.8.3.1
For some HCAs, ib_modify_qp() is an expensive operation running
virtualized.
For both the active and passive side, the QP returned by the CM has
the state set to RTS, so no need for this excess RTS -> RTS
transition. With IB Core's ability to set the RNR Retry timer, we use
this interface to shave off another ib_modify_qp().
Fixes: ec16227e1414 ("RDS/IB: Infiniband transport")
Signed-off-by: Håkon Bugge <[email protected]>
---
net/rds/ib_cm.c | 35 +----------------------------------
net/rds/rdma_transport.c | 1 +
2 files changed, 2 insertions(+), 34 deletions(-)
diff --git a/net/rds/ib_cm.c b/net/rds/ib_cm.c
index f5cbe96..26b069e 100644
--- a/net/rds/ib_cm.c
+++ b/net/rds/ib_cm.c
@@ -68,31 +68,6 @@ static void rds_ib_set_flow_control(struct rds_connection *conn, u32 credits)
}
/*
- * Tune RNR behavior. Without flow control, we use a rather
- * low timeout, but not the absolute minimum - this should
- * be tunable.
- *
- * We already set the RNR retry count to 7 (which is the
- * smallest infinite number :-) above.
- * If flow control is off, we want to change this back to 0
- * so that we learn quickly when our credit accounting is
- * buggy.
- *
- * Caller passes in a qp_attr pointer - don't waste stack spacv
- * by allocation this twice.
- */
-static void
-rds_ib_tune_rnr(struct rds_ib_connection *ic, struct ib_qp_attr *attr)
-{
- int ret;
-
- attr->min_rnr_timer = IB_RNR_TIMER_000_32;
- ret = ib_modify_qp(ic->i_cm_id->qp, attr, IB_QP_MIN_RNR_TIMER);
- if (ret)
- printk(KERN_NOTICE "ib_modify_qp(IB_QP_MIN_RNR_TIMER): err=%d\n", -ret);
-}
-
-/*
* Connection established.
* We get here for both outgoing and incoming connection.
*/
@@ -100,7 +75,6 @@ void rds_ib_cm_connect_complete(struct rds_connection *conn, struct rdma_cm_even
{
struct rds_ib_connection *ic = conn->c_transport_data;
const union rds_ib_conn_priv *dp = NULL;
- struct ib_qp_attr qp_attr;
__be64 ack_seq = 0;
__be32 credit = 0;
u8 major = 0;
@@ -168,14 +142,6 @@ void rds_ib_cm_connect_complete(struct rds_connection *conn, struct rdma_cm_even
* the posted credit count. */
rds_ib_recv_refill(conn, 1, GFP_KERNEL);
- /* Tune RNR behavior */
- rds_ib_tune_rnr(ic, &qp_attr);
-
- qp_attr.qp_state = IB_QPS_RTS;
- err = ib_modify_qp(ic->i_cm_id->qp, &qp_attr, IB_QP_STATE);
- if (err)
- printk(KERN_NOTICE "ib_modify_qp(IB_QP_STATE, RTS): err=%d\n", err);
-
/* update ib_device with this local ipaddr */
err = rds_ib_update_ipaddr(ic->rds_ibdev, &conn->c_laddr);
if (err)
@@ -947,6 +913,7 @@ int rds_ib_cm_handle_connect(struct rdma_cm_id *cm_id,
event->param.conn.responder_resources,
event->param.conn.initiator_depth, isv6);
+ rdma_set_min_rnr_timer(cm_id, IB_RNR_TIMER_000_32);
/* rdma_accept() calls rdma_reject() internally if it fails */
if (rdma_accept(cm_id, &conn_param))
rds_ib_conn_error(conn, "rdma_accept failed\n");
diff --git a/net/rds/rdma_transport.c b/net/rds/rdma_transport.c
index 5f741e5..a9e4ff9 100644
--- a/net/rds/rdma_transport.c
+++ b/net/rds/rdma_transport.c
@@ -87,6 +87,7 @@ static int rds_rdma_cm_event_handler_cmn(struct rdma_cm_id *cm_id,
case RDMA_CM_EVENT_ADDR_RESOLVED:
rdma_set_service_type(cm_id, conn->c_tos);
+ rdma_set_min_rnr_timer(cm_id, IB_RNR_TIMER_000_32);
/* XXX do we need to clean up if this fails? */
ret = rdma_resolve_route(cm_id,
RDS_RDMA_RESOLVE_TIMEOUT_MS);
--
1.8.3.1
Introduce the ability for kernel ULPs to adjust the minimum RNR Retry
timer. The INIT -> RTR transition executed by RDMA CM will be used for
this adjustment. This avoids an additional ib_modify_qp() call.
rdma_set_min_rnr_timer() must be called before the call to
rdma_connect() on the active side and before the call to rdma_accept()
on the passive side.
The default value of RNR Retry timer is zero, which translates to 655
ms. When the receiver is not ready to accept a send messages, it
encodes the RNR Retry timer value in the NAK. The requestor will then
wait at least the specified time value before retrying the send.
The 5-bit value to be supplied to the rdma_set_min_rnr_timer() is
documented in IBTA Table 45: "Encoding for RNR NAK Timer Field".
Signed-off-by: Håkon Bugge <[email protected]>
Acked-by: Jason Gunthorpe <[email protected]>
---
drivers/infiniband/core/cma.c | 41 ++++++++++++++++++++++++++++++++++++++
drivers/infiniband/core/cma_priv.h | 2 ++
include/rdma/rdma_cm.h | 2 ++
3 files changed, 45 insertions(+)
diff --git a/drivers/infiniband/core/cma.c b/drivers/infiniband/core/cma.c
index 9409651..5ce097d 100644
--- a/drivers/infiniband/core/cma.c
+++ b/drivers/infiniband/core/cma.c
@@ -852,6 +852,7 @@ static void cma_id_put(struct rdma_id_private *id_priv)
id_priv->id.qp_type = qp_type;
id_priv->tos_set = false;
id_priv->timeout_set = false;
+ id_priv->min_rnr_timer_set = false;
id_priv->gid_type = IB_GID_TYPE_IB;
spin_lock_init(&id_priv->lock);
mutex_init(&id_priv->qp_mutex);
@@ -1141,6 +1142,9 @@ int rdma_init_qp_attr(struct rdma_cm_id *id, struct ib_qp_attr *qp_attr,
if ((*qp_attr_mask & IB_QP_TIMEOUT) && id_priv->timeout_set)
qp_attr->timeout = id_priv->timeout;
+ if ((*qp_attr_mask & IB_QP_MIN_RNR_TIMER) && id_priv->min_rnr_timer_set)
+ qp_attr->min_rnr_timer = id_priv->min_rnr_timer;
+
return ret;
}
EXPORT_SYMBOL(rdma_init_qp_attr);
@@ -2615,6 +2619,43 @@ int rdma_set_ack_timeout(struct rdma_cm_id *id, u8 timeout)
}
EXPORT_SYMBOL(rdma_set_ack_timeout);
+/**
+ * rdma_set_min_rnr_timer() - Set the minimum RNR Retry timer of the
+ * QP associated with a connection identifier.
+ * @id: Communication identifier to associated with service type.
+ * @min_rnr_timer: 5-bit value encoded as Table 45: "Encoding for RNR NAK
+ * Timer Field" in the IBTA specification.
+ *
+ * This function should be called before rdma_connect() on active
+ * side, and on passive side before rdma_accept(). The timer value
+ * will be associated with the local QP. When it receives a send it is
+ * not read to handle, typically if the receive queue is empty, an RNR
+ * Retry NAK is returned to the requester with the min_rnr_timer
+ * encoded. The requester will then wait at least the time specified
+ * in the NAK before retrying. The default is zero, which translates
+ * to a minimum RNR Timer value of 655 ms.
+ *
+ * Return: 0 for success
+ */
+int rdma_set_min_rnr_timer(struct rdma_cm_id *id, u8 min_rnr_timer)
+{
+ struct rdma_id_private *id_priv;
+
+ /* It is a five-bit value */
+ if (min_rnr_timer & 0xe0)
+ return -EINVAL;
+
+ if (id->qp_type != IB_QPT_RC && id->qp_type != IB_QPT_XRC_TGT)
+ return -EINVAL;
+
+ id_priv = container_of(id, struct rdma_id_private, id);
+ id_priv->min_rnr_timer = min_rnr_timer;
+ id_priv->min_rnr_timer_set = true;
+
+ return 0;
+}
+EXPORT_SYMBOL(rdma_set_min_rnr_timer);
+
static void cma_query_handler(int status, struct sa_path_rec *path_rec,
void *context)
{
diff --git a/drivers/infiniband/core/cma_priv.h b/drivers/infiniband/core/cma_priv.h
index caece96..bf83d32 100644
--- a/drivers/infiniband/core/cma_priv.h
+++ b/drivers/infiniband/core/cma_priv.h
@@ -86,9 +86,11 @@ struct rdma_id_private {
u8 tos;
u8 tos_set:1;
u8 timeout_set:1;
+ u8 min_rnr_timer_set:1;
u8 reuseaddr;
u8 afonly;
u8 timeout;
+ u8 min_rnr_timer;
enum ib_gid_type gid_type;
/*
diff --git a/include/rdma/rdma_cm.h b/include/rdma/rdma_cm.h
index 32a67af..8b0f66e 100644
--- a/include/rdma/rdma_cm.h
+++ b/include/rdma/rdma_cm.h
@@ -331,6 +331,8 @@ int rdma_join_multicast(struct rdma_cm_id *id, struct sockaddr *addr,
int rdma_set_afonly(struct rdma_cm_id *id, int afonly);
int rdma_set_ack_timeout(struct rdma_cm_id *id, u8 timeout);
+
+int rdma_set_min_rnr_timer(struct rdma_cm_id *id, u8 min_rnr_timer);
/**
* rdma_get_service_id - Return the IB service ID for a specified address.
* @id: Communication identifier associated with the address.
--
1.8.3.1
[...]
Thanks Haakon. Patchset looks fine by me.
Acked-by: Santosh Shilimkar <[email protected]>
On Wed, Mar 31, 2021 at 08:43:13PM +0200, H?kon Bugge wrote:
> Introduce the ability for kernel ULPs to adjust the minimum RNR Retry
> timer. The INIT -> RTR transition executed by RDMA CM will be used for
> this adjustment. This avoids an additional ib_modify_qp() call.
>
> rdma_set_min_rnr_timer() must be called before the call to
> rdma_connect() on the active side and before the call to rdma_accept()
> on the passive side.
>
> The default value of RNR Retry timer is zero, which translates to 655
> ms. When the receiver is not ready to accept a send messages, it
> encodes the RNR Retry timer value in the NAK. The requestor will then
> wait at least the specified time value before retrying the send.
>
> The 5-bit value to be supplied to the rdma_set_min_rnr_timer() is
> documented in IBTA Table 45: "Encoding for RNR NAK Timer Field".
>
> Signed-off-by: H?kon Bugge <[email protected]>
> Acked-by: Jason Gunthorpe <[email protected]>
> ---
> drivers/infiniband/core/cma.c | 41 ++++++++++++++++++++++++++++++++++++++
> drivers/infiniband/core/cma_priv.h | 2 ++
> include/rdma/rdma_cm.h | 2 ++
> 3 files changed, 45 insertions(+)
>
> diff --git a/drivers/infiniband/core/cma.c b/drivers/infiniband/core/cma.c
> index 9409651..5ce097d 100644
> --- a/drivers/infiniband/core/cma.c
> +++ b/drivers/infiniband/core/cma.c
> @@ -852,6 +852,7 @@ static void cma_id_put(struct rdma_id_private *id_priv)
> id_priv->id.qp_type = qp_type;
> id_priv->tos_set = false;
> id_priv->timeout_set = false;
> + id_priv->min_rnr_timer_set = false;
> id_priv->gid_type = IB_GID_TYPE_IB;
> spin_lock_init(&id_priv->lock);
> mutex_init(&id_priv->qp_mutex);
> @@ -1141,6 +1142,9 @@ int rdma_init_qp_attr(struct rdma_cm_id *id, struct ib_qp_attr *qp_attr,
> if ((*qp_attr_mask & IB_QP_TIMEOUT) && id_priv->timeout_set)
> qp_attr->timeout = id_priv->timeout;
>
> + if ((*qp_attr_mask & IB_QP_MIN_RNR_TIMER) && id_priv->min_rnr_timer_set)
> + qp_attr->min_rnr_timer = id_priv->min_rnr_timer;
> +
> return ret;
> }
> EXPORT_SYMBOL(rdma_init_qp_attr);
> @@ -2615,6 +2619,43 @@ int rdma_set_ack_timeout(struct rdma_cm_id *id, u8 timeout)
> }
> EXPORT_SYMBOL(rdma_set_ack_timeout);
>
> +/**
> + * rdma_set_min_rnr_timer() - Set the minimum RNR Retry timer of the
> + * QP associated with a connection identifier.
> + * @id: Communication identifier to associated with service type.
> + * @min_rnr_timer: 5-bit value encoded as Table 45: "Encoding for RNR NAK
> + * Timer Field" in the IBTA specification.
> + *
> + * This function should be called before rdma_connect() on active
> + * side, and on passive side before rdma_accept(). The timer value
> + * will be associated with the local QP. When it receives a send it is
> + * not read to handle, typically if the receive queue is empty, an RNR
> + * Retry NAK is returned to the requester with the min_rnr_timer
> + * encoded. The requester will then wait at least the time specified
> + * in the NAK before retrying. The default is zero, which translates
> + * to a minimum RNR Timer value of 655 ms.
> + *
> + * Return: 0 for success
> + */
> +int rdma_set_min_rnr_timer(struct rdma_cm_id *id, u8 min_rnr_timer)
> +{
> + struct rdma_id_private *id_priv;
> +
> + /* It is a five-bit value */
> + if (min_rnr_timer & 0xe0)
> + return -EINVAL;
> +
> + if (id->qp_type != IB_QPT_RC && id->qp_type != IB_QPT_XRC_TGT)
> + return -EINVAL;
This is in-kernel API and safe to use WARN_ON() instead of returning
error which RDS is not checking anyway.
Thanks
On Wed, Mar 31, 2021 at 07:54:17PM +0000, Santosh Shilimkar wrote:
> [...]
>
> Thanks Haakon. Patchset looks fine by me.
> Acked-by: Santosh Shilimkar <[email protected]>
Jakub/Dave are you OK if I take this RDS patch rdma to rdma's tree?
Thanks,
Jason
> On 1 Apr 2021, at 19:51, Jason Gunthorpe <[email protected]> wrote:
>
> On Wed, Mar 31, 2021 at 07:54:17PM +0000, Santosh Shilimkar wrote:
>> [...]
>>
>> Thanks Haakon. Patchset looks fine by me.
>> Acked-by: Santosh Shilimkar <[email protected]>
>
> Jakub/Dave are you OK if I take this RDS patch rdma to rdma's tree?
Let me know if this is lingering due to Leon's comment about using WARN_ON() instead of error returns.
Håkon
On Wed, Mar 31, 2021 at 08:43:12PM +0200, Håkon Bugge wrote:
> ib_modify_qp() is an expensive operation on some HCAs running
> virtualized. This series removes two ib_modify_qp() calls from RDS.
>
> I am sending this as a v3, even though it is the first sent to
> net. This because the IB Core commit has reach v3.
>
> Håkon Bugge (2):
> IB/cma: Introduce rdma_set_min_rnr_timer()
> rds: ib: Remove two ib_modify_qp() calls
Applied to rdma for-next, thanks
Jason
On Mon, Apr 12, 2021 at 07:58:47PM -0300, Jason Gunthorpe wrote:
> On Wed, Mar 31, 2021 at 08:43:12PM +0200, H?kon Bugge wrote:
> > ib_modify_qp() is an expensive operation on some HCAs running
> > virtualized. This series removes two ib_modify_qp() calls from RDS.
> >
> > I am sending this as a v3, even though it is the first sent to
> > net. This because the IB Core commit has reach v3.
> >
> > H?kon Bugge (2):
> > IB/cma: Introduce rdma_set_min_rnr_timer()
> > rds: ib: Remove two ib_modify_qp() calls
>
> Applied to rdma for-next, thanks
Jason,
It should be
+ WARN_ON(id->qp_type != IB_QPT_RC && id->qp_type != IB_QPT_XRC_TGT);
and not
+ if (WARN_ON(id->qp_type != IB_QPT_RC && id->qp_type != IB_QPT_XRC_TGT))
+ return -EINVAL;
Thanks
>
> Jason
> On 7 Apr 2021, at 18:41, Haakon Bugge <[email protected]> wrote:
>
>
>
>> On 1 Apr 2021, at 19:51, Jason Gunthorpe <[email protected]> wrote:
>>
>> On Wed, Mar 31, 2021 at 07:54:17PM +0000, Santosh Shilimkar wrote:
>>> [...]
>>>
>>> Thanks Haakon. Patchset looks fine by me.
>>> Acked-by: Santosh Shilimkar <[email protected]>
>>
>> Jakub/Dave are you OK if I take this RDS patch rdma to rdma's tree?
>
> Let me know if this is lingering due to Leon's comment about using WARN_ON() instead of error returns.
A gentle ping.
Håkon
On Mon, Apr 12, 2021 at 06:35:35PM +0000, Haakon Bugge wrote:
>
>
> > On 7 Apr 2021, at 18:41, Haakon Bugge <[email protected]> wrote:
> >
> >
> >
> >> On 1 Apr 2021, at 19:51, Jason Gunthorpe <[email protected]> wrote:
> >>
> >> On Wed, Mar 31, 2021 at 07:54:17PM +0000, Santosh Shilimkar wrote:
> >>> [...]
> >>>
> >>> Thanks Haakon. Patchset looks fine by me.
> >>> Acked-by: Santosh Shilimkar <[email protected]>
> >>
> >> Jakub/Dave are you OK if I take this RDS patch rdma to rdma's tree?
> >
> > Let me know if this is lingering due to Leon's comment about using WARN_ON() instead of error returns.
>
> A gentle ping.
I will take it with Santos' ack.
Jason
On Tue, Apr 13, 2021 at 09:29:41AM +0300, Leon Romanovsky wrote:
> On Mon, Apr 12, 2021 at 07:58:47PM -0300, Jason Gunthorpe wrote:
> > On Wed, Mar 31, 2021 at 08:43:12PM +0200, Håkon Bugge wrote:
> > > ib_modify_qp() is an expensive operation on some HCAs running
> > > virtualized. This series removes two ib_modify_qp() calls from RDS.
> > >
> > > I am sending this as a v3, even though it is the first sent to
> > > net. This because the IB Core commit has reach v3.
> > >
> > > Håkon Bugge (2):
> > > IB/cma: Introduce rdma_set_min_rnr_timer()
> > > rds: ib: Remove two ib_modify_qp() calls
> >
> > Applied to rdma for-next, thanks
>
> Jason,
>
> It should be
> + WARN_ON(id->qp_type != IB_QPT_RC && id->qp_type != IB_QPT_XRC_TGT);
>
> and not
> + if (WARN_ON(id->qp_type != IB_QPT_RC && id->qp_type != IB_QPT_XRC_TGT))
> + return -EINVAL;
Unless we can completely remove the return code the if statement is a
reasonable way to use the WARN_ON here
Jason
> On 13 Apr 2021, at 08:29, Leon Romanovsky <[email protected]> wrote:
>
> On Mon, Apr 12, 2021 at 07:58:47PM -0300, Jason Gunthorpe wrote:
>> On Wed, Mar 31, 2021 at 08:43:12PM +0200, Håkon Bugge wrote:
>>> ib_modify_qp() is an expensive operation on some HCAs running
>>> virtualized. This series removes two ib_modify_qp() calls from RDS.
>>>
>>> I am sending this as a v3, even though it is the first sent to
>>> net. This because the IB Core commit has reach v3.
>>>
>>> Håkon Bugge (2):
>>> IB/cma: Introduce rdma_set_min_rnr_timer()
>>> rds: ib: Remove two ib_modify_qp() calls
>>
>> Applied to rdma for-next, thanks
>
> Jason,
>
> It should be
> + WARN_ON(id->qp_type != IB_QPT_RC && id->qp_type != IB_QPT_XRC_TGT);
With no return you will arm the setting of the timer and subsequently get an error from the modify_qp later.
Håkon
>
> and not
> + if (WARN_ON(id->qp_type != IB_QPT_RC && id->qp_type != IB_QPT_XRC_TGT))
> + return -EINVAL;
>
> Thanks
>
>>
>> Jason
On Tue, Apr 13, 2021 at 11:13:38AM +0000, Haakon Bugge wrote:
>
>
> > On 13 Apr 2021, at 08:29, Leon Romanovsky <[email protected]> wrote:
> >
> > On Mon, Apr 12, 2021 at 07:58:47PM -0300, Jason Gunthorpe wrote:
> >> On Wed, Mar 31, 2021 at 08:43:12PM +0200, H?kon Bugge wrote:
> >>> ib_modify_qp() is an expensive operation on some HCAs running
> >>> virtualized. This series removes two ib_modify_qp() calls from RDS.
> >>>
> >>> I am sending this as a v3, even though it is the first sent to
> >>> net. This because the IB Core commit has reach v3.
> >>>
> >>> H?kon Bugge (2):
> >>> IB/cma: Introduce rdma_set_min_rnr_timer()
> >>> rds: ib: Remove two ib_modify_qp() calls
> >>
> >> Applied to rdma for-next, thanks
> >
> > Jason,
> >
> > It should be
> > + WARN_ON(id->qp_type != IB_QPT_RC && id->qp_type != IB_QPT_XRC_TGT);
>
> With no return you will arm the setting of the timer and subsequently get an error from the modify_qp later.
The addition of WARN_ON() means that this is programmer error to get
such input. Historically, in-kernel API doesn't need to have protection
from other kernel developers.
Thanks
>
>
> H?kon
>
> >
> > and not
> > + if (WARN_ON(id->qp_type != IB_QPT_RC && id->qp_type != IB_QPT_XRC_TGT))
> > + return -EINVAL;
> >
> > Thanks
> >
> >>
> >> Jason
>