From: Moni Shoua <monis@xxxxxxxxxxxx>
Introduce a new verb named ibv_advise_mr(), it includes:
- The application interface.
- The command interface with the kernel.
The purpose of this patch is to give an advice to the kernel
about an address range belongs to a memory region.
Performance - applications that are aware of future access patterns can
use this verb in order to leverage this knowledge to improve system or
application performance.
One example is for pre-fetching a range part of an on-demand paging MR.
On-demand-paging (ODP) is a technique to alleviate much of the
shortcomings of memory registration. The main idea is that applications
no longer pin down the underlying physical pages of the address space
and need not track the validity of the mappings. Rather, the HCA
requests the latest translations from the OS when pages are not present,
and the OS invalidates translations which are no longer valid due to
mapping changes. Pre-fetching ODP address ranges, therefore make them
present before the actual IO is conducted. This would provide a way to
reduce latency by overlapping paging-in and either compute time or IO to
other ranges.
Signed-off-by: Moni Shoua <monis@xxxxxxxxxxxx>
Signed-off-by: Aviad Yehezkel <aviadye@xxxxxxxxxxxx>
Reviewed-by: Guy Levi <guyle@xxxxxxxxxxxx>
Signed-off-by: Yishai Hadas <yishaih@xxxxxxxxxxxx>
---
libibverbs/CMakeLists.txt | 1 +
libibverbs/cmd_mr.c | 54 ++++++++++++++++
libibverbs/driver.h | 10 +++
libibverbs/dummy_ops.c | 11 ++++
libibverbs/libibverbs.map.in | 1 +
libibverbs/man/CMakeLists.txt | 1 +
libibverbs/man/ibv_advise_mr.3.md | 126 ++++++++++++++++++++++++++++++++++++++
libibverbs/verbs.h | 28 +++++++++
libibverbs/verbs_api.h | 6 ++
9 files changed, 238 insertions(+)
create mode 100644 libibverbs/cmd_mr.c
create mode 100644 libibverbs/man/ibv_advise_mr.3.md
diff --git a/libibverbs/CMakeLists.txt b/libibverbs/CMakeLists.txt
index ddf5995..2ddafd6 100644
--- a/libibverbs/CMakeLists.txt
+++ b/libibverbs/CMakeLists.txt
@@ -36,6 +36,7 @@ rdma_library(ibverbs "${CMAKE_CURRENT_BINARY_DIR}/libibverbs.map"
cmd_fallback.c
cmd_flow_action.c
cmd_ioctl.c
+ cmd_mr.c
compat-1_0.c
device.c
dummy_ops.c
diff --git a/libibverbs/cmd_mr.c b/libibverbs/cmd_mr.c
new file mode 100644
index 0000000..aee63a8
--- /dev/null
+++ b/libibverbs/cmd_mr.c
@@ -0,0 +1,54 @@
+/*
+ * Copyright (c) 2018 Mellanox Technologies, Ltd. All rights reserved.
+ *
+ * This software is available to you under a choice of one of two
+ * licenses. You may choose to be licensed under the terms of the GNU
+ * General Public License (GPL) Version 2, available from the file
+ * COPYING in the main directory of this source tree, or the
+ * OpenIB.org BSD license below:
+ *
+ * Redistribution and use in source and binary forms, with or
+ * without modification, are permitted provided that the following
+ * conditions are met:
+ *
+ * - Redistributions of source code must retain the above
+ * copyright notice, this list of conditions and the following
+ * disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following
+ * disclaimer in the documentation and/or other materials
+ * provided with the distribution.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#include <infiniband/cmd_ioctl.h>
+#include <rdma/ib_user_ioctl_cmds.h>
+#include <infiniband/driver.h>
+
+int ibv_cmd_advise_mr(struct ibv_pd *pd,
+ enum ibv_advise_mr_advice advice,
+ uint32_t flags,
+ struct ibv_sge *sg_list,
+ uint32_t num_sge)
+{
+ DECLARE_COMMAND_BUFFER(cmd, UVERBS_OBJECT_MR,
+ UVERBS_METHOD_ADVISE_MR,
+ 4);
+
+ fill_attr_in_obj(cmd, UVERBS_ATTR_ADVISE_MR_PD_HANDLE, pd->handle);
+ fill_attr_const_in(cmd, UVERBS_ATTR_ADVISE_MR_ADVICE, advice);
+ fill_attr_in_uint32(cmd, UVERBS_ATTR_ADVISE_MR_FLAGS, flags);
+ fill_attr_in_ptr_array(cmd, UVERBS_ATTR_ADVISE_MR_SGE_LIST,
+ sg_list, num_sge);
+
+ return execute_ioctl(pd->context, cmd);
+}
diff --git a/libibverbs/driver.h b/libibverbs/driver.h
index 9030dc8..b9f648c 100644
--- a/libibverbs/driver.h
+++ b/libibverbs/driver.h
@@ -218,6 +218,11 @@ struct verbs_counters {
* Keep sorted.
*/
struct verbs_context_ops {
+ int (*advise_mr)(struct ibv_pd *pd,
+ enum ibv_advise_mr_advice advice,
+ uint32_t flags,
+ struct ibv_sge *sg_list,
+ uint32_t num_sges);
struct ibv_dm *(*alloc_dm)(struct ibv_context *context,
struct ibv_alloc_dm_attr *attr);
struct ibv_mw *(*alloc_mw)(struct ibv_pd *pd, enum ibv_mw_type type);
@@ -440,6 +445,11 @@ int ibv_cmd_rereg_mr(struct verbs_mr *vmr, uint32_t flags, void *addr,
size_t cmd_sz, struct ib_uverbs_rereg_mr_resp *resp,
size_t resp_sz);
int ibv_cmd_dereg_mr(struct verbs_mr *vmr);
+int ibv_cmd_advise_mr(struct ibv_pd *pd,
+ enum ibv_advise_mr_advice advice,
+ uint32_t flags,
+ struct ibv_sge *sg_list,
+ uint32_t num_sge);
int ibv_cmd_alloc_mw(struct ibv_pd *pd, enum ibv_mw_type type,
struct ibv_mw *mw, struct ibv_alloc_mw *cmd,
size_t cmd_size,
diff --git a/libibverbs/dummy_ops.c b/libibverbs/dummy_ops.c
index 43f8430..a5e9380 100644
--- a/libibverbs/dummy_ops.c
+++ b/libibverbs/dummy_ops.c
@@ -33,6 +33,15 @@
#include "ibverbs.h"
#include <errno.h>
+static int advise_mr(struct ibv_pd *pd,
+ enum ibv_advise_mr_advice advice,
+ uint32_t flags,
+ struct ibv_sge *sg_list,
+ uint32_t num_sges)
+{
+ return ENOSYS;
+}
+
static struct ibv_dm *alloc_dm(struct ibv_context *context,
struct ibv_alloc_dm_attr *attr)
{
@@ -436,6 +445,7 @@ static int resize_cq(struct ibv_cq *cq, int cqe)
* Keep sorted.
*/
const struct verbs_context_ops verbs_dummy_ops = {
+ advise_mr,
alloc_dm,
alloc_mw,
alloc_null_mr,
@@ -550,6 +560,7 @@ void verbs_set_ops(struct verbs_context *vctx,
} \
} while (0)
+ SET_OP(vctx, advise_mr);
SET_OP(vctx, alloc_dm);
SET_OP(ctx, alloc_mw);
SET_OP(vctx, alloc_null_mr);
diff --git a/libibverbs/libibverbs.map.in b/libibverbs/libibverbs.map.in
index c489c76..4bffb1b 100644
--- a/libibverbs/libibverbs.map.in
+++ b/libibverbs/libibverbs.map.in
@@ -120,6 +120,7 @@ IBVERBS_PRIVATE_@IBVERBS_PABI_VERSION@ {
__ioctl_final_num_attrs;
_verbs_init_and_alloc_context;
execute_ioctl;
+ ibv_cmd_advise_mr;
ibv_cmd_alloc_dm;
ibv_cmd_alloc_mw;
ibv_cmd_alloc_pd;
diff --git a/libibverbs/man/CMakeLists.txt b/libibverbs/man/CMakeLists.txt
index 6efd671..4d5abef 100644
--- a/libibverbs/man/CMakeLists.txt
+++ b/libibverbs/man/CMakeLists.txt
@@ -1,4 +1,5 @@
rdma_man_pages(
+ ibv_advise_mr.3.md
ibv_alloc_dm.3
ibv_alloc_mw.3
ibv_alloc_null_mr.3.md
diff --git a/libibverbs/man/ibv_advise_mr.3.md b/libibverbs/man/ibv_advise_mr.3.md
new file mode 100644
index 0000000..e2f51e6
--- /dev/null
+++ b/libibverbs/man/ibv_advise_mr.3.md
@@ -0,0 +1,126 @@
+---
+date: 2018-10-19
+footer: libibverbs
+header: "Libibverbs Programmer's Manual"
+layout: page
+license: 'Licensed under the OpenIB.org BSD license (FreeBSD Variant) - See COPYING.md'
+section: 3
+title: IBV_ADVISE_MR
+---
+
+# NAME
+
+ibv_advise_mr - Gives advice or directions to the kernel about an
+ address range belongs to a memory region (MR).
+
+# SYNOPSIS
+
+```c
+#include <infiniband/verbs.h>
+
+int ibv_advise_mr(struct ibv_pd *pd,
+ enum ibv_advise_mr_advice advice,
+ uint32_t flags,
+ struct ibv_sge *sg_list,
+ uint32_t num_sge)
+```
+
+# DESCRIPTION
+
+**ibv_advise_mr()** Give advice or directions to the kernel about an
+address range belonging to a memory region (MR).
+Applications that are aware of future access patterns can use this verb
+in order to leverage this knowledge to improve system or
+application performance.
+
+**Conventional advice values**
+
+*IBV_ADVISE_MR_ADVICE_PREFETCH*
+: Pre-fetch a range of an on-demand paging MR.
+ Make pages present with read-only permission before the actual IO is conducted.
+ This would provide a way to reduce latency by overlapping paging-in
+ and either compute time or IO to other ranges.
+
+*IBV_ADVISE_MR_ADVICE_PREFETCH_WRITE*
+: Like IBV_ADVISE_MR_ADVICE_PREFETCH but with read-access
+ and write-access permission to the fetched memory.
+
+# ARGUMENTS
+*pd*
+: The protection domain (PD) associated with the MR.
+
+*advice*
+: The requested advise value (as listed above).
+
+*flags*
+: Describes the properties of the advise operation
+ **Conventional advice values**
+ *IBV_ADVISE_MR_FLAG_FLUSH*
+ : Request to be a synchronized operation. Return to the caller
+ after the operation is completed.
+
+*sg_list*
+: Pointer to the s/g array
+ When using IBV_ADVISE_OP_PREFETCH advise value, all the lkeys of all
+ the scatter gather elements (SGEs) must be associated with ODP MRs
+ (MRs that were registered with IBV_ACCESS_ON_DEMAND).
+
+*num_sge*
+: Number of elements in the s/g array
+
+# RETURN VALUE
+
+**ibv_advise_mr()** returns 0 when the call was successful, or the value
+ of errno on failure (which indicates the failure reason).
+
+*ENOSYS*
+: libibverbs or provider driver doesn't support the ibv_advise_mr() verb.
+
+*ENOTSUP*
+: The advise operation isn't supported.
+
+*EFAULT*
+: In one of the following:
+ o When the range requested is out of the MR bounds, or when parts of
+ it are not part of the process address space.
+ o One of the lkeys provided in the scatter gather list is invalid or
+ with wrong write access.
+
+*EINVAL*
+: In one of the following:
+ o The PD is invalid.
+ o The flags are invalid.
+
+# NOTES
+
+An application may pre-fetch any address range within an ODP MR when using the
+**IBV_ADVISE_MR_ADVICE_PREFETCH** or **IBV_ADVISE_MR_ADVICE_PREFETCH_WRITE** advice.
+Semantically, this operation is best-effort. That means the kernel does not
+guarantee that underlying pages are updated in the HCA or the pre-fetched pages
+would remain resident.
+
+When using **IBV_ADVISE_MR_ADVICE_PREFETCH** or **IBV_ADVISE_MR_ADVICE_PREFETCH_WRITE**
+advice, the operation will be done in the following stages:
+ o Page in the user pages to memory (pages aren't pinned).
+ o Get the dma mapping of these user pages.
+ o Post the underlying page translations to the HCA.
+
+If **IBV_ADVISE_MR_FLAG_FLUSH** is specified then the underlying pages are
+guaranteed to be updated in the HCA before returning SUCCESS.
+Otherwise the driver can choose to postpone the posting of the new translations
+to the HCA.
+When performing a local RDMA access operation it is recommended to use
+IBV_ADVISE_MR_FLAG_FLUSH flag with one of the pre-fetch advices to
+increase probability that the pages translations are valid in the HCA
+and avoid future page faults.
+
+# SEE ALSO
+
+**ibv_reg_mr**(3),
+**ibv_rereg_mr**(3),
+**ibv_dereg_mr**(3)
+
+# AUTHOR
+
+Aviad Yehezkel <aviadye@xxxxxxxxxxxx>
+
diff --git a/libibverbs/verbs.h b/libibverbs/verbs.h
index 62c6922..caf78f4 100644
--- a/libibverbs/verbs.h
+++ b/libibverbs/verbs.h
@@ -1786,6 +1786,11 @@ struct ibv_values_ex {
struct verbs_context {
/* "grows up" - new fields go here */
+ int (*advise_mr)(struct ibv_pd *pd,
+ enum ibv_advise_mr_advice advice,
+ uint32_t flags,
+ struct ibv_sge *sg_list,
+ uint32_t num_sges);
struct ibv_mr *(*alloc_null_mr)(struct ibv_pd *pd);
int (*read_counters)(struct ibv_counters *counters,
uint64_t *counters_value,
@@ -2210,6 +2215,29 @@ struct ibv_comp_channel *ibv_create_comp_channel(struct ibv_context *context);
int ibv_destroy_comp_channel(struct ibv_comp_channel *channel);
/**
+ * ibv_advise_mr - Gives advice about an address range in MRs
+ * @pd - protection domain of all MRs for which the advice is for
+ * @advice - type of advice
+ * @flags - advice modifiers
+ * @sg_list - an array of memory ranges
+ * @num_sge - number of elements in the array
+ */
+static inline int ibv_advise_mr(struct ibv_pd *pd,
+ enum ibv_advise_mr_advice advice,
+ uint32_t flags,
+ struct ibv_sge *sg_list,
+ uint32_t num_sge)
+{
+ struct verbs_context *vctx;
+
+ vctx = verbs_get_ctx_op(pd->context, advise_mr);
+ if (!vctx)
+ return ENOSYS;
+
+ return vctx->advise_mr(pd, advice, flags, sg_list, num_sge);
+}
+
+/**
* ibv_alloc_dm - Allocate device memory
* @context - Context DM will be attached to
* @attr - Attributes to allocate the DM with
diff --git a/libibverbs/verbs_api.h b/libibverbs/verbs_api.h
index 4ac1335..bdfd677 100644
--- a/libibverbs/verbs_api.h
+++ b/libibverbs/verbs_api.h
@@ -85,6 +85,12 @@
#define ibv_flow_action_esp_encap ib_uverbs_flow_action_esp_encap
#define ibv_flow_action_esp ib_uverbs_flow_action_esp
+#define ibv_advise_mr_advice ib_uverbs_advise_mr_advice
+#define IBV_ADVISE_MR_ADVICE_PREFETCH IB_UVERBS_ADVISE_MR_ADVICE_PREFETCH
+#define IBV_ADVISE_MR_ADVICE_PREFETCH_WRITE IB_UVERBS_ADVISE_MR_ADVICE_PREFETCH_WRITE
+
+#define IBV_ADVISE_MR_FLAG_FLUSH IB_UVERBS_ADVISE_MR_FLAG_FLUSH
+
#define IBV_QPF_GRH_REQUIRED IB_UVERBS_QPF_GRH_REQUIRED
#endif
--
1.8.3.1
