Hi Maxime, > > Hi, > > > > I'm trying to make a vhost-user initiator built upon DPDK work with > > 2MB hugepages. In the initiator we have to share all memory with the host > process, so it can perform DMA. DPDK currently enforces having one descriptor > per hugepage and there's an artificial limit of shared descriptors in DPDK > vhost-user implementation (currently 8). Because of that, all DPDK vhost-user > initiators are practically limited to 1GB hugepages at the moment. We can > always increase the artificial descriptor limit, but then we're limited by > sendmsg() itself, which on Linux accepts no more than 253 descriptors. > However, could we increase the vhost-user implementation limit to - say - 128, > and bring back "single file segments" [1]? > > If you do something like this, you'll have first to update the vhost-user > spec, > which should I think include a new protocol feature bit.
Do I? I can't see any memory region limitation in the vhost-user spec [1]. If a 128-region initiator tries to connect to an 8-region rte_vhost, the recvmsg() would simply fail - rte_vhost rejects `truncated` messages. > > Also, you will have to consider improving the translation functions with a > better > search algorithm, else you'll have very poor performance. That's right, I got that sorted out already. Regards, D. [1] https://github.com/qemu/qemu/blob/master/docs/interop/vhost-user.txt
