On Wed, Dec 14, 2016 at 5:15 AM, Jerome Glisse <jglisse@xxxxxxxxxx> wrote: > I would like to discuss un-addressable device memory in the context of > filesystem and block device. Specificaly how to handle write-back, read, > ... when a filesystem page is migrated to device memory that CPU can not > access. > > I intend to post a patchset leveraging the same idea as the existing > block bounce helper (block/bounce.c) to handle this. I believe this is > worth discussing during summit see how people feels about such plan and > if they have better ideas. > > Yes, that would be interesting. I presume all of this is for ZONE_DEVICE and HMM. I think designing such an interface requires careful thought on tracking pages to ensure we don't lose writes and also the impact on things like the writeback subsytem. >From a HMM perspective and an overall MM perspective, I worry that our accounting system is broken with the proposed mirroring and unaddressable memory that needs to be addressed as well. It would also be nice to have a discussion on migration patches currently on the list 1. THP migration 2. HMM migration 3. Async migration > I also like to join discussions on: > - Peer-to-Peer DMAs between PCIe devices > - CDM coherent device memory Yes, this needs discussion. Specifically from is all of CDM memory NORMAL or not and the special requirements we have today for CDM. > - PMEM > - overall mm discussions Balbir Singh. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>