Re: [Qemu-devel] [PATCH 1/2] migration: update index field when delete or qsort RDMALocalBlock

[858585 jemmy]

On Wed, May 9, 2018 at 1:19 AM, Dr. David Alan Gilbert
<address@hidden> wrote:
> * Lidong Chen (address@hidden) wrote:
>> rdma_delete_block function deletes RDMALocalBlock base on index field,
>> but not update the index field. So when next time invoke rdma_delete_block,
>> it will not work correctly.
>>
>> If start and cancel migration repeatedly, some RDMALocalBlock not invoke
>> ibv_dereg_mr to decrease kernel mm_struct vmpin. When vmpin is large than
>> max locked memory limitation, ibv_reg_mr will failed, and migration can not
>> start successfully again.
>>
>> Signed-off-by: Lidong Chen <address@hidden>
>> ---
>>  migration/rdma.c | 7 +++++++
>>  1 file changed, 7 insertions(+)
>>
>> diff --git a/migration/rdma.c b/migration/rdma.c
>> index ed9cfb1..0dd4033 100644
>> --- a/migration/rdma.c
>> +++ b/migration/rdma.c
>> @@ -713,6 +713,9 @@ static int rdma_delete_block(RDMAContext *rdma, 
>> RDMALocalBlock *block)
>>              memcpy(local->block + block->index, old + (block->index + 1),
>>                  sizeof(RDMALocalBlock) *
>>                      (local->nb_blocks - (block->index + 1)));
>> +            for (x = block->index; x < local->nb_blocks - 1; x++) {
>> +                local->block[x].index--;
>> +            }
>
> Yes; is that equivalent to   local->blocks[x].index = x;   ?

yes, it's equivalent.

>
>>          }
>>      } else {
>>          assert(block == local->block);
>> @@ -3398,6 +3401,10 @@ static int qemu_rdma_registration_handle(QEMUFile *f, 
>> void *opaque)
>>              qsort(rdma->local_ram_blocks.block,
>>                    rdma->local_ram_blocks.nb_blocks,
>>                    sizeof(RDMALocalBlock), dest_ram_sort_func);
>> +            for (i = 0; i < local->nb_blocks; i++) {
>> +                local->block[i].index = i;
>> +            }
>> +
>
> Which is basically the way that one does it;
>
> OK, it's a while since I looked at this but I think it fixes my 3 year
> old 03fcab38617 patch, so
>
>
>
> Reviewed-by: Dr. David Alan Gilbert <address@hidden>
>
>>              if (rdma->pin_all) {
>>                  ret = qemu_rdma_reg_whole_ram_blocks(rdma);
>>                  if (ret) {
>> --
>> 1.8.3.1
>>
> --
> Dr. David Alan Gilbert / address@hidden / Manchester, UK