Hi, restarting an old topic, 05/01/2017 16:52, Tan, Jianfeng: > On 1/5/2017 5:34 AM, Walker, Benjamin wrote: > >>> Note that this > >>> probably means that using uio on recent kernels is subtly > >>> broken and cannot be supported going forward because there > >>> is no uio mechanism to pin the memory. > >>> > >>> The first open question I have is whether DPDK should allow > >>> uio at all on recent (4.x) kernels. My current understanding > >>> is that there is no way to pin memory and hugepages can now > >>> be moved around, so uio would be unsafe. What does the > >>> community think here? > > Back to this question, removing uio support in DPDK seems a little > overkill to me. Can we just document it down? Like, firstly warn users > do not invoke migrate_pages() or move_pages() to a DPDK process; as for > the kcompactd daemon and some more cases (like compaction could be > triggered by alloc_pages()), could we just recommend to disable > CONFIG_COMPACTION?
We really need to better document the limitations of UIO. May we have some suggestions here? > Another side, how does vfio pin those memory? Through memlock (from code > in vfio_pin_pages())? So why not just mlock those hugepages? Good question. Why not mlock the hugepages?
