On Thu, Dec 11, 2014 at 01:23:11PM -0800, Maxim Patlasov wrote: > Hello, > > I would like to have a discussion about current state of kernel AIO - an > interface that lets kernel callers submit aio iocbs without going through > the user space syscalls. The patches implementing the feature were developed > and sent to mailing lists many times by Zach Brown and Dave Kleikamp long > while ago. Then, after LSF/MM 2014, Alexander Viro made significant progress > wiring ITER_BVEC into VFS call paths. His efforts made adding support of > kernel AIO much easier as was recently demonstrated by Ming Lei's patches > converting loop driver to blk-mq, but for some reasons the feature is still > out of tree. An interesting aspect of the problem to be discussed is > blocking/nonblocking behavior of aio_kernel_submit: even if it blocks only > in rare cases, the caller (e.g. loop driver) must always use a separate > thread for processing - extra overhead that can be avoided. > > Thanks, > Maxim > Just to chime in, there's also discussion of bringing in kernel AIO for generic swapfile support (introduced for swap-over-NFS, in development for BTRFS), so the feature has at least a couple of use cases already. -- Omar -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
