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

["Dr. David Alan Gilbert" <dgilbert@redhat.com>]

* Lidong Chen (jemmy858585@gmail.com) 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 <lidongchen@tencent.com>
> ---
>  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;   ?

>          }
>      } 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 <dgilbert@redhat.com>

>              if (rdma->pin_all) {
>                  ret = qemu_rdma_reg_whole_ram_blocks(rdma);
>                  if (ret) {
> -- 
> 1.8.3.1
> 
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK