This got addressed in https://github.com/grpc/grpc/pull/12353, thanks!

On Wednesday, August 30, 2017 at 10:22:02 PM UTC-7, [email protected] wrote:
>
> Hello,
>
> I found this by code inspection when debugging a (potential) memory leak 
> (or at least a huge increase in memory usage) under load.
>
> This section of tcp_do_read() sets up the iovecs for the recvmsg() system 
> call:
>
>   for (i = 0; i < tcp->incoming_buffer->count; i++) {
>     iov[i].iov_base = 
> GRPC_SLICE_START_PTR(tcp->incoming_buffer->slices[i]);
>     iov[i].iov_len = GRPC_SLICE_LENGTH(tcp->incoming_buffer->slices[i]);
>   }
>
>   msg.msg_name = NULL;
>   msg.msg_namelen = 0;
>   msg.msg_iov = iov;
>   *msg.msg_iovlen = tcp->iov_size;*
>   msg.msg_control = NULL;
>   msg.msg_controllen = 0;
>   msg.msg_flags = 0;
>
>
> We create one iovec for each of the slices in tcp->incoming_buffer, but 
> then we tell recvmsg() that the number of slices is tcp->iov_size (instead 
> of tcp->incoming_buffer->count). tcp->iov_size is always 1 (it is assigned 
> only once, in grpc_tcp_create()).
>
> This means that we only use the first slice to read into, even though we 
> meant to use all (up to) 4; the other slices end up being saved until the 
> next call in tcp->last_read_buffer.
>
> I don't fully understand the memory allocation consequences of this; at 
> the very least, this messes with the target_length estimates.
>
> Thanks,
> -Tudor.
>

-- 
You received this message because you are subscribed to the Google Groups 
"grpc.io" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to [email protected].
To post to this group, send email to [email protected].
Visit this group at https://groups.google.com/group/grpc-io.
To view this discussion on the web visit 
https://groups.google.com/d/msgid/grpc-io/6ecdf47c-df39-4539-ae45-d128addece24%40googlegroups.com.
For more options, visit https://groups.google.com/d/optout.

Reply via email to