Hi, I'd like to attend LSF/MM, in particular the following topics and areas: -- The get_user_pages()+DMA problem. Here, the page tracking technique seems fairly well settled. I've posted an RFC for the page tracking [1], and also posted the first two put_user_pages() patches as non-RFC [2]. However, the interactions with filesystems are still under active discussion. That is, what to do when clear_page_dirty_for_io() lands on a page that has an active get_user_pages() caller: this is still being discussed. I think there are viable solutions and we're getting there, and I *really* hope we might actually converge on an approach at this conference. Although, it's very awkward that Dave Chinner can't make it! -- Amir Goldstein proposed a "Sharing file backed pages" TOPIC, and this is very closely related to the gup/dma issues above, so I want to be there for that. And generally, get_user_pages and file system interactions are of course thing I want to be involved in lately. This next one was partially covered in Zi Yan's ATTEND request. But his focus was slightly different, so I wanted to come at it from a slightly different perspective, which is: -- THP and huge pages in general. It turns out that some high-thread-count devices (GPUs, of course, but also various AI chips and FPGA solutions) do much, much better with 2MB pages. In fact, it's so important that we've been expecting to be forced to use hugetlbfs, in order to be guaranteed those size pages. However, it would be better if the system could instead, reliably and efficiently provide huge pages, to the point that a GPU-like device could more or less always get a 2 MB page when it needs it. Also, perhaps a minor point: there don't seem to be kernel-side allocators for huge pages, but in order for device drivers to use them, it seems like that would be required. [1] https://lore.kernel.org/r/20190204052135.25784-1-jhubbard@xxxxxxxxxx [2] https://lore.kernel.org/r/20190208075649.3025-1-jhubbard@xxxxxxxxxx thanks, -- John Hubbard NVIDIA ----------------------------------------------------------------------------------- This email message is for the sole use of the intended recipient(s) and may contain confidential information. Any unauthorized review, use, disclosure or distribution is prohibited. If you are not the intended recipient, please contact the sender by reply email and destroy all copies of the original message. -----------------------------------------------------------------------------------
