Damien Le Moal <damien.lemoal@xxxxxxxxxxxxxxxxxx> writes: > On 2/22/22 04:59, Gabriel Krisman Bertazi wrote: >> I'd like to discuss an interface to implement user space block devices, >> while avoiding local network NBD solutions. There has been reiterated >> interest in the topic, both from researchers [1] and from the community, >> including a proposed session in LSFMM2018 [2] (though I don't think it >> happened). >> >> I've been working on top of the Google iblock implementation to find >> something upstreamable and would like to present my design and gather >> feedback on some points, in particular zero-copy and overall user space >> interface. >> >> The design I'm pending towards uses special fds opened by the driver to >> transfer data to/from the block driver, preferably through direct >> splicing as much as possible, to keep data only in kernel space. This >> is because, in my use case, the driver usually only manipulates >> metadata, while data is forwarded directly through the network, or >> similar. It would be neat if we can leverage the existing >> splice/copy_file_range syscalls such that we don't ever need to bring >> disk data to user space, if we can avoid it. I've also experimented >> with regular pipes, But I found no way around keeping a lot of pipes >> opened, one for each possible command 'slot'. >> >> [1] https://dl.acm.org/doi/10.1145/3456727.3463768 > > This is $15 for non ACM members... Any public download available ? Hi Damien, Yes. Sorry for the ACM link. yuck. One of the authors published the paper here: https://rgmacedo.github.io/files/2021/systor21-bdus/bdus-paper.pdf > >> [2] https://www.spinics.net/lists/linux-fsdevel/msg120674.html >> -- Gabriel Krisman Bertazi
