diff mbox series

[1/2] migration/rdma: Try to register On-Demand Paging memory region

Message ID 20210731140332.8701-2-lizhijian@cn.fujitsu.com
State New
Headers show
Series enable fsdax rdma migration | expand

Commit Message

Li Zhijian July 31, 2021, 2:03 p.m. UTC 
Previously, for the fsdax mem-backend-file, it will register failed with
Operation not supported. In this case, we can try to register it with
On-Demand Paging[1] like what rpma_mr_reg() does on rpma[2].

[1]: https://community.mellanox.com/s/article/understanding-on-demand-paging--odp-x
[2]: http://pmem.io/rpma/manpages/v0.9.0/rpma_mr_reg.3
Signed-off-by: Li Zhijian <lizhijian@cn.fujitsu.com>
---
 migration/rdma.c       | 27 ++++++++++++++++++---------
 migration/trace-events |  1 +
 2 files changed, 19 insertions(+), 9 deletions(-)

Comments

Marcel Apfelbaum Aug. 22, 2021, 8:53 a.m. UTC | #1 
Hi

On Sat, Jul 31, 2021 at 5:00 PM Li Zhijian <lizhijian@cn.fujitsu.com> wrote:
>
> Previously, for the fsdax mem-backend-file, it will register failed with
> Operation not supported. In this case, we can try to register it with
> On-Demand Paging[1] like what rpma_mr_reg() does on rpma[2].
>
> [1]: https://community.mellanox.com/s/article/understanding-on-demand-paging--odp-x
> [2]: http://pmem.io/rpma/manpages/v0.9.0/rpma_mr_reg.3
> Signed-off-by: Li Zhijian <lizhijian@cn.fujitsu.com>
> ---
>  migration/rdma.c       | 27 ++++++++++++++++++---------
>  migration/trace-events |  1 +
>  2 files changed, 19 insertions(+), 9 deletions(-)
>
> diff --git a/migration/rdma.c b/migration/rdma.c
> index 5c2d113aa94..8784b5f22a6 100644
> --- a/migration/rdma.c
> +++ b/migration/rdma.c
> @@ -1123,15 +1123,21 @@ static int qemu_rdma_reg_whole_ram_blocks(RDMAContext *rdma)
>      RDMALocalBlocks *local = &rdma->local_ram_blocks;
>
>      for (i = 0; i < local->nb_blocks; i++) {
> +        int access = IBV_ACCESS_LOCAL_WRITE | IBV_ACCESS_REMOTE_WRITE;
> +
> +on_demand:
>          local->block[i].mr =
>              ibv_reg_mr(rdma->pd,
>                      local->block[i].local_host_addr,
> -                    local->block[i].length,
> -                    IBV_ACCESS_LOCAL_WRITE |
> -                    IBV_ACCESS_REMOTE_WRITE
> +                    local->block[i].length, access
>                      );
>          if (!local->block[i].mr) {
> -            perror("Failed to register local dest ram block!");
> +            if (!(access & IBV_ACCESS_ON_DEMAND) && errno == ENOTSUP) {
> +                access |= IBV_ACCESS_ON_DEMAND;
> +                trace_qemu_rdma_register_odp_mr(local->block[i].block_name);
> +                goto on_demand;

Wouldn't it be better to check first if the device supports ODP ?
Something like:
    ret = ibv_exp_query_device(context, &dattr);
    if (dattr.exp_device_cap_flags & IBV_EXP_DEVICE_ODP)...

Also, I  am not (personally) too fond of the "on_demand" label usage here,
however I will let the maintainer/others decide.

Thanks,
Marcel

> +            }
> +            perror("Failed to register local dest ram block!\n");
>              break;
>          }
>          rdma->total_registrations++;
> @@ -1215,15 +1221,18 @@ static int qemu_rdma_register_and_get_keys(RDMAContext *rdma,
>       */
>      if (!block->pmr[chunk]) {
>          uint64_t len = chunk_end - chunk_start;
> +        int access = rkey ? IBV_ACCESS_LOCAL_WRITE | IBV_ACCESS_REMOTE_WRITE : 0;
>
>          trace_qemu_rdma_register_and_get_keys(len, chunk_start);
>
> -        block->pmr[chunk] = ibv_reg_mr(rdma->pd,
> -                chunk_start, len,
> -                (rkey ? (IBV_ACCESS_LOCAL_WRITE |
> -                        IBV_ACCESS_REMOTE_WRITE) : 0));
> -
> +on_demand:
> +        block->pmr[chunk] = ibv_reg_mr(rdma->pd, chunk_start, len, access);
>          if (!block->pmr[chunk]) {
> +            if (!(access & IBV_ACCESS_ON_DEMAND) && errno == ENOTSUP) {
> +                access |= IBV_ACCESS_ON_DEMAND;
> +                trace_qemu_rdma_register_odp_mr(block->block_name);
> +                goto on_demand;
> +            }
>              perror("Failed to register chunk!");
>              fprintf(stderr, "Chunk details: block: %d chunk index %d"
>                              " start %" PRIuPTR " end %" PRIuPTR
> diff --git a/migration/trace-events b/migration/trace-events
> index a1c0f034ab8..5f6aa580def 100644
> --- a/migration/trace-events
> +++ b/migration/trace-events
> @@ -212,6 +212,7 @@ qemu_rdma_poll_write(const char *compstr, int64_t comp, int left, uint64_t block
>  qemu_rdma_poll_other(const char *compstr, int64_t comp, int left) "other completion %s (%" PRId64 ") received left %d"
>  qemu_rdma_post_send_control(const char *desc) "CONTROL: sending %s.."
>  qemu_rdma_register_and_get_keys(uint64_t len, void *start) "Registering %" PRIu64 " bytes @ %p"
> +qemu_rdma_register_odp_mr(const char *name) "Try to register On-Demand Paging memory region: %s"
>  qemu_rdma_registration_handle_compress(int64_t length, int index, int64_t offset) "Zapping zero chunk: %" PRId64 " bytes, index %d, offset %" PRId64
>  qemu_rdma_registration_handle_finished(void) ""
>  qemu_rdma_registration_handle_ram_blocks(void) ""
> --
> 2.31.1
>
>
>
>
Li Zhijian Aug. 23, 2021, 1:41 a.m. UTC | #2 
On 22/08/2021 16:53, Marcel Apfelbaum wrote:
> Hi
>
> On Sat, Jul 31, 2021 at 5:00 PM Li Zhijian <lizhijian@cn.fujitsu.com> wrote:
>> Previously, for the fsdax mem-backend-file, it will register failed with
>> Operation not supported. In this case, we can try to register it with
>> On-Demand Paging[1] like what rpma_mr_reg() does on rpma[2].
>>
>> [1]: https://community.mellanox.com/s/article/understanding-on-demand-paging--odp-x
>> [2]: http://pmem.io/rpma/manpages/v0.9.0/rpma_mr_reg.3
>> Signed-off-by: Li Zhijian <lizhijian@cn.fujitsu.com>
>> ---
>>   migration/rdma.c       | 27 ++++++++++++++++++---------
>>   migration/trace-events |  1 +
>>   2 files changed, 19 insertions(+), 9 deletions(-)
>>
>> diff --git a/migration/rdma.c b/migration/rdma.c
>> index 5c2d113aa94..8784b5f22a6 100644
>> --- a/migration/rdma.c
>> +++ b/migration/rdma.c
>> @@ -1123,15 +1123,21 @@ static int qemu_rdma_reg_whole_ram_blocks(RDMAContext *rdma)
>>       RDMALocalBlocks *local = &rdma->local_ram_blocks;
>>
>>       for (i = 0; i < local->nb_blocks; i++) {
>> +        int access = IBV_ACCESS_LOCAL_WRITE | IBV_ACCESS_REMOTE_WRITE;
>> +
>> +on_demand:
>>           local->block[i].mr =
>>               ibv_reg_mr(rdma->pd,
>>                       local->block[i].local_host_addr,
>> -                    local->block[i].length,
>> -                    IBV_ACCESS_LOCAL_WRITE |
>> -                    IBV_ACCESS_REMOTE_WRITE
>> +                    local->block[i].length, access
>>                       );
>>           if (!local->block[i].mr) {
>> -            perror("Failed to register local dest ram block!");
>> +            if (!(access & IBV_ACCESS_ON_DEMAND) && errno == ENOTSUP) {
>> +                access |= IBV_ACCESS_ON_DEMAND;
>> +                trace_qemu_rdma_register_odp_mr(local->block[i].block_name);
>> +                goto on_demand;
> Wouldn't it be better to check first if the device supports ODP ?
> Something like:
>      ret = ibv_exp_query_device(context, &dattr);
>      if (dattr.exp_device_cap_flags & IBV_EXP_DEVICE_ODP)...

Good idea !



>
> Also, I  am not (personally) too fond of the "on_demand" label usage here,
> however I will let the maintainer/others decide.
Indeed, how just repeating the ibv_reg_mr() instead of a 'go to'

Thanks
Zhijian



>
> Thanks,
> Marcel
>
>> +            }
>> +            perror("Failed to register local dest ram block!\n");
>>               break;
>>           }
>>           rdma->total_registrations++;
>> @@ -1215,15 +1221,18 @@ static int qemu_rdma_register_and_get_keys(RDMAContext *rdma,
>>        */
>>       if (!block->pmr[chunk]) {
>>           uint64_t len = chunk_end - chunk_start;
>> +        int access = rkey ? IBV_ACCESS_LOCAL_WRITE | IBV_ACCESS_REMOTE_WRITE : 0;
>>
>>           trace_qemu_rdma_register_and_get_keys(len, chunk_start);
>>
>> -        block->pmr[chunk] = ibv_reg_mr(rdma->pd,
>> -                chunk_start, len,
>> -                (rkey ? (IBV_ACCESS_LOCAL_WRITE |
>> -                        IBV_ACCESS_REMOTE_WRITE) : 0));
>> -
>> +on_demand:
>> +        block->pmr[chunk] = ibv_reg_mr(rdma->pd, chunk_start, len, access);
>>           if (!block->pmr[chunk]) {
>> +            if (!(access & IBV_ACCESS_ON_DEMAND) && errno == ENOTSUP) {
>> +                access |= IBV_ACCESS_ON_DEMAND;
>> +                trace_qemu_rdma_register_odp_mr(block->block_name);
>> +                goto on_demand;
>> +            }
>>               perror("Failed to register chunk!");
>>               fprintf(stderr, "Chunk details: block: %d chunk index %d"
>>                               " start %" PRIuPTR " end %" PRIuPTR
>> diff --git a/migration/trace-events b/migration/trace-events
>> index a1c0f034ab8..5f6aa580def 100644
>> --- a/migration/trace-events
>> +++ b/migration/trace-events
>> @@ -212,6 +212,7 @@ qemu_rdma_poll_write(const char *compstr, int64_t comp, int left, uint64_t block
>>   qemu_rdma_poll_other(const char *compstr, int64_t comp, int left) "other completion %s (%" PRId64 ") received left %d"
>>   qemu_rdma_post_send_control(const char *desc) "CONTROL: sending %s.."
>>   qemu_rdma_register_and_get_keys(uint64_t len, void *start) "Registering %" PRIu64 " bytes @ %p"
>> +qemu_rdma_register_odp_mr(const char *name) "Try to register On-Demand Paging memory region: %s"
>>   qemu_rdma_registration_handle_compress(int64_t length, int index, int64_t offset) "Zapping zero chunk: %" PRId64 " bytes, index %d, offset %" PRId64
>>   qemu_rdma_registration_handle_finished(void) ""
>>   qemu_rdma_registration_handle_ram_blocks(void) ""
>> --
>> 2.31.1
>>
>>
>>
>>
>
Marcel Apfelbaum Aug. 23, 2021, 7:03 a.m. UTC | #3 
Hi Zhijian,

On Mon, Aug 23, 2021 at 4:41 AM lizhijian@fujitsu.com
<lizhijian@fujitsu.com> wrote:
>
>
>
> On 22/08/2021 16:53, Marcel Apfelbaum wrote:
> > Hi
> >
> > On Sat, Jul 31, 2021 at 5:00 PM Li Zhijian <lizhijian@cn.fujitsu.com> wrote:
> >> Previously, for the fsdax mem-backend-file, it will register failed with
> >> Operation not supported. In this case, we can try to register it with
> >> On-Demand Paging[1] like what rpma_mr_reg() does on rpma[2].
> >>
> >> [1]: https://community.mellanox.com/s/article/understanding-on-demand-paging--odp-x
> >> [2]: http://pmem.io/rpma/manpages/v0.9.0/rpma_mr_reg.3
> >> Signed-off-by: Li Zhijian <lizhijian@cn.fujitsu.com>
> >> ---
> >>   migration/rdma.c       | 27 ++++++++++++++++++---------
> >>   migration/trace-events |  1 +
> >>   2 files changed, 19 insertions(+), 9 deletions(-)
> >>
> >> diff --git a/migration/rdma.c b/migration/rdma.c
> >> index 5c2d113aa94..8784b5f22a6 100644
> >> --- a/migration/rdma.c
> >> +++ b/migration/rdma.c
> >> @@ -1123,15 +1123,21 @@ static int qemu_rdma_reg_whole_ram_blocks(RDMAContext *rdma)
> >>       RDMALocalBlocks *local = &rdma->local_ram_blocks;
> >>
> >>       for (i = 0; i < local->nb_blocks; i++) {
> >> +        int access = IBV_ACCESS_LOCAL_WRITE | IBV_ACCESS_REMOTE_WRITE;
> >> +
> >> +on_demand:
> >>           local->block[i].mr =
> >>               ibv_reg_mr(rdma->pd,
> >>                       local->block[i].local_host_addr,
> >> -                    local->block[i].length,
> >> -                    IBV_ACCESS_LOCAL_WRITE |
> >> -                    IBV_ACCESS_REMOTE_WRITE
> >> +                    local->block[i].length, access
> >>                       );
> >>           if (!local->block[i].mr) {
> >> -            perror("Failed to register local dest ram block!");
> >> +            if (!(access & IBV_ACCESS_ON_DEMAND) && errno == ENOTSUP) {
> >> +                access |= IBV_ACCESS_ON_DEMAND;
> >> +                trace_qemu_rdma_register_odp_mr(local->block[i].block_name);
> >> +                goto on_demand;
> > Wouldn't it be better to check first if the device supports ODP ?
> > Something like:
> >      ret = ibv_exp_query_device(context, &dattr);
> >      if (dattr.exp_device_cap_flags & IBV_EXP_DEVICE_ODP)...
>
> Good idea !
>
>
>
> >
> > Also, I  am not (personally) too fond of the "on_demand" label usage here,
> > however I will let the maintainer/others decide.
> Indeed, how just repeating the ibv_reg_mr() instead of a 'go to'
>

Any "boring"/standard approach would do.

Thanks,
Marcel

> Thanks
> Zhijian
>
>
>
> >
> > Thanks,
> > Marcel
> >
> >> +            }
> >> +            perror("Failed to register local dest ram block!\n");
> >>               break;
> >>           }
> >>           rdma->total_registrations++;
> >> @@ -1215,15 +1221,18 @@ static int qemu_rdma_register_and_get_keys(RDMAContext *rdma,
> >>        */
> >>       if (!block->pmr[chunk]) {
> >>           uint64_t len = chunk_end - chunk_start;
> >> +        int access = rkey ? IBV_ACCESS_LOCAL_WRITE | IBV_ACCESS_REMOTE_WRITE : 0;
> >>
> >>           trace_qemu_rdma_register_and_get_keys(len, chunk_start);
> >>
> >> -        block->pmr[chunk] = ibv_reg_mr(rdma->pd,
> >> -                chunk_start, len,
> >> -                (rkey ? (IBV_ACCESS_LOCAL_WRITE |
> >> -                        IBV_ACCESS_REMOTE_WRITE) : 0));
> >> -
> >> +on_demand:
> >> +        block->pmr[chunk] = ibv_reg_mr(rdma->pd, chunk_start, len, access);
> >>           if (!block->pmr[chunk]) {
> >> +            if (!(access & IBV_ACCESS_ON_DEMAND) && errno == ENOTSUP) {
> >> +                access |= IBV_ACCESS_ON_DEMAND;
> >> +                trace_qemu_rdma_register_odp_mr(block->block_name);
> >> +                goto on_demand;
> >> +            }
> >>               perror("Failed to register chunk!");
> >>               fprintf(stderr, "Chunk details: block: %d chunk index %d"
> >>                               " start %" PRIuPTR " end %" PRIuPTR
> >> diff --git a/migration/trace-events b/migration/trace-events
> >> index a1c0f034ab8..5f6aa580def 100644
> >> --- a/migration/trace-events
> >> +++ b/migration/trace-events
> >> @@ -212,6 +212,7 @@ qemu_rdma_poll_write(const char *compstr, int64_t comp, int left, uint64_t block
> >>   qemu_rdma_poll_other(const char *compstr, int64_t comp, int left) "other completion %s (%" PRId64 ") received left %d"
> >>   qemu_rdma_post_send_control(const char *desc) "CONTROL: sending %s.."
> >>   qemu_rdma_register_and_get_keys(uint64_t len, void *start) "Registering %" PRIu64 " bytes @ %p"
> >> +qemu_rdma_register_odp_mr(const char *name) "Try to register On-Demand Paging memory region: %s"
> >>   qemu_rdma_registration_handle_compress(int64_t length, int index, int64_t offset) "Zapping zero chunk: %" PRId64 " bytes, index %d, offset %" PRId64
> >>   qemu_rdma_registration_handle_finished(void) ""
> >>   qemu_rdma_registration_handle_ram_blocks(void) ""
> >> --
> >> 2.31.1
> >>
> >>
> >>
> >>
> >
diff mbox series

Patch

diff --git a/migration/rdma.c b/migration/rdma.c
index 5c2d113aa94..8784b5f22a6 100644
--- a/migration/rdma.c
+++ b/migration/rdma.c
@@ -1123,15 +1123,21 @@  static int qemu_rdma_reg_whole_ram_blocks(RDMAContext *rdma)
     RDMALocalBlocks *local = &rdma->local_ram_blocks;
 
     for (i = 0; i < local->nb_blocks; i++) {
+        int access = IBV_ACCESS_LOCAL_WRITE | IBV_ACCESS_REMOTE_WRITE;
+
+on_demand:
         local->block[i].mr =
             ibv_reg_mr(rdma->pd,
                     local->block[i].local_host_addr,
-                    local->block[i].length,
-                    IBV_ACCESS_LOCAL_WRITE |
-                    IBV_ACCESS_REMOTE_WRITE
+                    local->block[i].length, access
                     );
         if (!local->block[i].mr) {
-            perror("Failed to register local dest ram block!");
+            if (!(access & IBV_ACCESS_ON_DEMAND) && errno == ENOTSUP) {
+                access |= IBV_ACCESS_ON_DEMAND;
+                trace_qemu_rdma_register_odp_mr(local->block[i].block_name);
+                goto on_demand;
+            }
+            perror("Failed to register local dest ram block!\n");
             break;
         }
         rdma->total_registrations++;
@@ -1215,15 +1221,18 @@  static int qemu_rdma_register_and_get_keys(RDMAContext *rdma,
      */
     if (!block->pmr[chunk]) {
         uint64_t len = chunk_end - chunk_start;
+        int access = rkey ? IBV_ACCESS_LOCAL_WRITE | IBV_ACCESS_REMOTE_WRITE : 0;
 
         trace_qemu_rdma_register_and_get_keys(len, chunk_start);
 
-        block->pmr[chunk] = ibv_reg_mr(rdma->pd,
-                chunk_start, len,
-                (rkey ? (IBV_ACCESS_LOCAL_WRITE |
-                        IBV_ACCESS_REMOTE_WRITE) : 0));
-
+on_demand:
+        block->pmr[chunk] = ibv_reg_mr(rdma->pd, chunk_start, len, access);
         if (!block->pmr[chunk]) {
+            if (!(access & IBV_ACCESS_ON_DEMAND) && errno == ENOTSUP) {
+                access |= IBV_ACCESS_ON_DEMAND;
+                trace_qemu_rdma_register_odp_mr(block->block_name);
+                goto on_demand;
+            }
             perror("Failed to register chunk!");
             fprintf(stderr, "Chunk details: block: %d chunk index %d"
                             " start %" PRIuPTR " end %" PRIuPTR
diff --git a/migration/trace-events b/migration/trace-events
index a1c0f034ab8..5f6aa580def 100644
--- a/migration/trace-events
+++ b/migration/trace-events
@@ -212,6 +212,7 @@  qemu_rdma_poll_write(const char *compstr, int64_t comp, int left, uint64_t block
 qemu_rdma_poll_other(const char *compstr, int64_t comp, int left) "other completion %s (%" PRId64 ") received left %d"
 qemu_rdma_post_send_control(const char *desc) "CONTROL: sending %s.."
 qemu_rdma_register_and_get_keys(uint64_t len, void *start) "Registering %" PRIu64 " bytes @ %p"
+qemu_rdma_register_odp_mr(const char *name) "Try to register On-Demand Paging memory region: %s"
 qemu_rdma_registration_handle_compress(int64_t length, int index, int64_t offset) "Zapping zero chunk: %" PRId64 " bytes, index %d, offset %" PRId64
 qemu_rdma_registration_handle_finished(void) ""
 qemu_rdma_registration_handle_ram_blocks(void) ""